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Speed,Combat,Scale,Racing => Scale Models => Topic started by: Tim Wescott on January 14, 2018, 02:40:59 PM

Title: Ercoupe Build (slow)
Post by: Tim Wescott on January 14, 2018, 02:40:59 PM
My ride for the Regionals in May, if I can get it done.  I just got the plans from the printer -- they lack detail.

Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on January 21, 2018, 07:58:05 PM
And ain't I making fast progress?  I'll be lucky to have something flyable -- I think I have too many irons in the fire.

I haven't decided yet whether I'm going to drill holes for my usual stunt jig.  I've chosen to use the original airfoil, so there's not a flat line anywhere to set on a building board.  I'll probably do this on a jig -- it just seems more sane.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on January 28, 2018, 05:07:59 PM
Nineteen ribs cut, at least nineteen more to go.  So far I've been progressing without drawing up plans, but I should maybe at least sketch out the rib layout & which ribs need to be shortened as I go into the wing tips.  Hmm.
Title: Re: Ercoupe Build (slow)
Post by: wwwarbird on January 28, 2018, 08:45:06 PM

 Just curious, what will the wingspan be?
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on January 28, 2018, 08:52:13 PM
Just curious, what will the wingspan be?

1/8 scale, 60".  I'm trying for not to big, not too small.
Title: Re: Ercoupe Build (slow)
Post by: wwwarbird on January 28, 2018, 09:29:41 PM

 That's a pretty good sized model, a nice size for scale though. A whole different ballgame, but over the years I've considered doing an Ercoupe stunt model many times. This one will be an interesting build to watch.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on February 03, 2018, 05:00:40 PM
All ribs cut.  I had originally planned on a 2" spacing, but I got to thinking and I decided that 2.5" would be OK (I'm not trying to match the original).  I have the main rib in a CAD program, so I just scaled it down to fit between the LE and TE for the two tip ribs.

20 main ribs
2 mid-tip ribs
2 end-tip ribs

I need to cut holes for lines in the ribs next, then start bending wood for the wingtips.
Title: Re: Ercoupe Build (slow)
Post by: Fred Cronenwett on February 03, 2018, 09:03:09 PM
That is a great size, big enough you can install a servo and other hardware and not be worried about wing loading. Small models can not tolerate adding the scale details and heavy items such as extra servos.

Another thing that happens with the larger models is that the wing loading per square foot can go up and still fly great. My 96" span B-29 flies with a 39 ounce per square foot wing loading, that same wing loading on a smaller model it would not get the off the ground. the 14 lb overall weight for the B-29 is a pig by stunt standards but flies just like the real B-29 so it's a good model for CL scale.

Math is on your side, if you double the size of the model from 30" to 60" you have doubled the size of the model but the wing area is 400% the area of the smaller model.

30" model would have 142.6 sq inches
60" model would have 570.4 sq inches

You can easily fly the larger model even if the model comes in at 5.5 lbs, but with the smaller 30" model you would be lucky to get airborne if the model came in at 1.25 lbs (or 20 ounces). I tend to round to the nearest 1/4 lb with the scale models instead of quoting model weight to the nearest ounce.

Fred
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on February 10, 2018, 06:25:40 PM
Small progress made on airplane - large progress made on shop.

Sunday or Monday I went into the back shop to find some wood for a tip form, and found that the last of the florescent fixtures had died.  I am sick and tired of florescents, so I've spent my evenings this week installing LED shoplights.  The good news is that it's brighter back there than it has been for years, and I still have the other half of the fixtures to install.  The better news is that it was all overhead work, and my right shoulder hasn't been bugging me for it -- so maybe in 2019 I can get back to flying stunt!

After taking a break from building to fix up my back shop where all the carpentry stuff lives, I ended up making the tip form out of cardboard, in the front shop.  I've got six 22x3/8x1/8 sticks soaking in ammonia water now; tomorrow I'll see if I can bend them.  If I can't hand bend them, I'll heat bend them.  I was going to say "I'll have to figure out how", but as I typed that a solution popped into my head.  Now that I can SEE my welding bench Igrab some pipe and make up a 4" or 6" diameter form that I can hold in my vise and heat up with a propane torch while I'm bending wood over it -- that should be both effective and gonzo, and if I'm careful, perhaps even let me finish the job before I burn down my house.

One of these days I'm going to have to try steam bending balsa.  I've had really, really good success bending wet balsa over a soldering iron for small rubber-powered airplanes.  So balsa seems to be good for heat-bending.  On the other hand, I've seen web sites that say you just cannot steam-bend kiln-dried wood.  I'm not sure if that means that other heat-bending techniques work, or that when you're working with thin sections of wood you can effectively undo the kiln drying by overnight soaking in water.
Title: Re: Ercoupe Build (slow)
Post by: Will Hinton on February 11, 2018, 10:13:39 AM
Tim, I heat bend kiln dried wood all the time, and hardwood at that when I'm building acoustic guitars.  I've bent maple, rosewood, koa, cherry, mahogany and the like.  I do soak them over night before doing it, but I can't imagine having problems heat bending balsa, even really hard balsa if it's plenty wet.
I feed the torch into one end of an aluminum tube with a baffle an inch from the opposite end to retain as much heat as possible.  I use a four inch and a two inch tubing, depending on the radius of the bend I need.
Just go slow and watch the fingers!  Good luck with it.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on February 11, 2018, 02:27:45 PM
Tim, I heat bend kiln dried wood all the time, and hardwood at that when I'm building acoustic guitars...

Thanks.  It sounds like you do the same as I do -- wet wood over a hot dry thing.  Have you even steam-bent, or does that just not fit into your process?

I'm going to try today with a heat gun, because I don't have any hunks of metal that are a nice 4" radius, other than a cookie tin.  If I get desperate I'll shove the torch into that, but I'm worried about burning up the tin.
Title: Re: Ercoupe Build (slow)
Post by: John Rist on February 11, 2018, 03:09:05 PM
Balsa wood bends if you soak it in a mixture of household ammonia and water.  I did some molded ringmaster leading edges this way.
Title: Re: Ercoupe Build (slow)
Post by: Will Hinton on February 11, 2018, 07:50:34 PM
I would like to have a steam bender, but the way I'm doing it works well enough for me to not spend the extra money on one.  The main thing I have to watch is burning the surface of this expensive exotic wood if I am too slow on my process.  The burns sand out, but at a huge cost of time.
Some of the bending machines available for luthiers are also wonderful machines, but also expensive.  If I were ever to up my output on a steady basis I would likely go that route, but for now; status quo is working well.  I just delivered two new acoustics last week and will start two new acoustic instruments in a couple of weeks.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on February 11, 2018, 08:43:23 PM
Balsa wood bends if you soak it in a mixture of household ammonia and water.  I did some molded ringmaster leading edges this way.

You can get it around a much tighter radius with heat.  I've done both.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on February 11, 2018, 08:55:20 PM
You can get it around a much tighter radius with heat.  I've done both.

I need to expand on that:

You can bend a thicker piece of wood around a tighter radius, and when you're done it'll stay there.  If you soak the wood in ammonia water (or plain water for longer, or water with a touch of soap), you can bend a piece around a form tighter than you can dry, and it won't break, and it'll take a bit of a set.  But if you bend it around a hot form you can get it much tighter, and it'll stay.

I've got a Bostonian I call the "Square Coupe" (I have this thing about Ercopes) with tips and tails bent out of 1/16" balsa over a soldering iron: the tail feathers are bent around a 5/16" radius (the radius of a penny, more or less) in places, and while that's as tight as I'd ever want to go with that sized wood, it worked great.  Basically, the vertical stabilizers were bent so that just sitting there they had the right shape on the plan.



Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on February 11, 2018, 09:42:38 PM
One wingtip bent.  I'll let it cool and dry overnight, or until I get a chance to get down to the shop again.

I ended up using a monocoat gun pointed at a round cookie tin loaded with scrap iron to hold it in place.  You let the wood heat up, it gets flexible, and then you can gently pull it around the form.  If you push it into a bend, or if you get impatient, then it buckles -- which I did, and it did, because I got impatient ("I got impatient and then screwed up" is a running theme in my building, I'm sorry to say).

If I do better tomorrow with the other wingtip, I may go for a 3rd round and see if I can make more pieces with less buckling this time.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on February 18, 2018, 05:01:17 PM
Wingtips bent, sorta kinda acceptably.  (meaning, it's good I'll be using opaque covering).

My cousin is learning guitar building; he bends moistened wood that's wrapped in foil -- I'm gonna try that next time, because I've noticed that the wood seems to bend nicely until it dries out, and then bends no more.

Oh, and wing plans done, such as they are.  Masking tape on the building board and a sharpie marker.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on February 18, 2018, 07:57:54 PM
Wing taking shape.  It's beginning to look like progress!

Note that the plan is for a very "stunt-ish" wing structure: LE sheeting, capstrips, TE sheeting, with center-section sheeting.  I'm just closing my eyes to what the actual structure of the wing may have been, or whether my particular full-scale example had a fabric- or metal-covered wing (they came both ways, fabric wings have been converted to metal, and sometimes converted back to fabric -- it's very much a question of what your particular example did).  If this were a more precision event, I'd care -- which is exactly why I chose Profile Scale.
Title: Re: Ercoupe Build (slow)
Post by: Trostle on February 19, 2018, 10:05:24 AM
That's a pretty good sized model, a nice size for scale though. A whole different ballgame, but over the years I've considered doing an Ercoupe stunt model many times. This one will be an interesting build to watch.

Just a comment here on the Ercoupe for semi-scale stunt.  Bob Palmers Mars, Model Airplane News, August 1952, sort of looks like an Ercoupe with it twin verticals, bubble canopy, and tricycle gear.   Cowled in side mounted engine with apple cheeks. (And it is OTS legal.)

Charles Lickliter's Ballerina, Flying Models, October 1959, is another that gives an impression of an Ercoupe with it twin vertical, bubble canopy, but had a conventional gear.   Cowled in inverted engine.  I-Beam construction.

Both of these models were attractive in their own ways particularly if you like twin vertical tails.

Keith


Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on February 19, 2018, 05:54:36 PM
LE and bottom half of the TE sheeting in place.  I've agonized about the order of the TE sheeting vs. getting the tip hoop & ribs in place -- I finally realized I was suffering from analysis paralysis, and just got 'er done.  Done and wrong can be fixed.  Never done can't.

TE sheeting is being held up by a 1/2" square stick that's held up by wedges cut to match the angle of the bottoms of the ribs.  The top TE sheeting will be tapered in the back, and will, well, set on top.  If you squint, you'll (maybe) be able to see that I had to block the spar up to make room for the LE to glue on.  I'm going to make all the screwups on this side, so that the inboard side will be perfect.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on February 19, 2018, 06:00:38 PM
I was just reading an Ercoupe pilot's website, and see that there's a scale maneuver unique to the Ercoupe that can best be described as "mush to landing".  Basically, if you fear overshooting the runway, you throttle way back and hold the stick back as far as you can.  The Ercoupe is stall- and spin-proof, so it'll sink pretty fast in a mushing glide.  The trick is to remember that you simply don't have enough airspeed for a flair, so you absolutely need to put the nose down at 200 feet so that you have enough airspeed for landing (and, apparently, to clean the passenger's seat of any residue if you're flying with a non-Ercoupe pilot who you failed to warn).  1/6 scale 200 feet is 33 feet -- so, probably not a maneuver for CL scale.

Note that I've never flown a scale Ercoupe -- but I've had RC planes with similar stall characteristics, and by golly I've done similar things trying to get them to spin.  It does work, sorta.
Title: Re: Ercoupe Build (slow)
Post by: wwwarbird on February 19, 2018, 06:28:31 PM
Just a comment here on the Ercoupe for semi-scale stunt.  Bob Palmers Mars, Model Airplane News, August 1952, sort of looks like an Ercoupe with it twin verticals, bubble canopy, and tricycle gear.   Cowled in side mounted engine with apple cheeks. (And it is OTS legal.)

 Thanks Keith, yeah, I've eyeballed the Mars before thinking the same thing, it could easily be bashed into an Ercoupe.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on March 29, 2018, 12:38:08 PM
I got to the point of getting that nice heat-bent wingtip installed and stalled for a while.  The upside of just starting to build is that you don't have to figure it all out ahead of time.  The downside is that you're constantly painting yourself into corners.

At any rate, here it is mocked up, showing slight progress.
Title: Re: Ercoupe Build (slow)
Post by: Avaiojet on March 29, 2018, 12:49:25 PM
I got to the point of getting that nice heat-bent wingtip installed and stalled for a while.  The upside of just starting to build is that you don't have to figure it all out ahead of time.  The downside is that you're constantly painting yourself into corners.

At any rate, here it is mocked up, showing slight progress.

Really really nice.  H^^

I looked on line. Lots of color choices.

CB
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on March 29, 2018, 02:04:10 PM
I looked on line. Lots of color choices.

It was a popular plane.  I have a walk-around set of photos, for a plane that's basic red and white.  I'm probably going to use whatever red and white comes out of Rustoleum canss, and take my lumps for not trying to match things exactly.
Title: Re: Ercoupe Build (slow)
Post by: wwwarbird on April 04, 2018, 08:53:01 PM

 May is right around the corner.   S?P ;D
Title: Re: Ercoupe Build (slow)
Post by: wwwarbird on May 19, 2018, 10:37:25 PM

 How's the 'Coupe coming?

Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on May 20, 2018, 08:00:47 AM
How's the 'Coupe coming?

Between Work, Life, and a design-as-you-go approach, I got stalled.  If I make the Regionals with the plane, it won't be 2018!  The big demotivator was getting my shoulder in shape for flying stunt, which suddenly meant that the Call of the Wild has me out flying.

I got stuck on making the wingtip look good and not be a construction nightmare.  As part of this, the actual bent-wood tip hoop went on with about a 1/8" gap between the end of the spar and the hoop, which stalled me.  I finally broke down and extended the spar, even though the result looks like the joinery that you'll never see in a 150-year-old barn, because the ones done that badly have all fallen down.  Once I managed to go ahead and make the joint, though, I could get work done and the wing is ready for LE sheeting.
Title: Re: Ercoupe Build (slow)
Post by: wwwarbird on May 20, 2018, 09:11:32 PM

 Hmm, looks like adding those diagonals would have been a good idea anyway. Heck, add them to the other tip too and it'll look like you knew what you were doing the whole time.  ;D
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on June 02, 2018, 06:10:42 PM
Oh, it's a good thing I'm chronicling this -- I just looked at the picture I'm posting and realized two things.  First, that I left out the holes for the leadouts.  I was planning on making holes "later" -- later came, and I was still forgetting.  This is really later -- fortunately I haven't glued anything down yet.  Second, I almost built two left wings, because I built the other wing upside down over the plans, and just started this one rightside up.  So -- off to drill holes and fit spar notches on the topside of the wing.

Oh -- and I'm making progress.  Two 1/4" square sticks stripped from my stock of 11-pound balsa (because it's for spars, and I'm trying to use up the heavy wood).
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on June 02, 2018, 06:26:01 PM
And I need to make a @#$% bellcrank.  Or finally rip apart my Nobler, which will never fly again.  But I think I'll make one.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on June 02, 2018, 07:23:37 PM
For stunt, I've been making my own bellcranks from 1/8" phenolic.  I see no reason not to here, because I'm just doing a bog standard 2-wire setup and using a radio for throttle control.  I've been making nifty bellcrank bearings from aluminum on my lathe, holding them on with nuts scavenged from potentiometers.  Just now, I realized that a potentiometer is a nifty bellcrank bearing, you just need to do some disassembly to get to the good part.

I'm not sure if the thing is zinc or aluminum -- I'd hesitate to use it for stunt without a lot of thought (and possibly testing), but I don't see this airplane getting hundreds of flights a year, so it's probably OK.  The actual bearing is the part at about 2 1/4 inches on the ruler.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on June 03, 2018, 11:15:56 PM
Right wing starting to be framed up (with leadout holes, thank goodness!).  You can see the left wing in the background with clothspins all over the inboard rib -- that's because I've been building straight wings for so long, I forgot that you want to angle the top of the inboard rib inward to accommodate it.  D'oh (or T'oh if you want to be classy and say it in French...)  So I glued another rib onto the first, and will sand things to the correct angle.

Second picture is the bellcrank, bearing courtesy of Alps electronics.  Before you ask -- yes, it'll be a floating bellcrank.  I'm pretty sure I'm going to mount it between the first two ribs of the right wing, so that the leadout position will be nice, and so that I don't have to hassle with getting the bellcrank to work correctly around the dihedral joint.  But I may change my mind -- the downside of engineering as you go is that you paint yourself into corners.  The upside is, there's no plans to disagree with when you decide to make changes.
Title: Re: Ercoupe Build (slow)
Post by: John Rist on June 06, 2018, 09:42:35 PM
Love the work bench.  Looks like mine!   LL~
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on June 08, 2018, 10:24:01 AM
Snuck in to my shop on the way to work.  Got the second wing LE installed.  Note the super high-tech clamping system.  The older I get, the less prone I am to using commercial clamping products -- weights, cloths pins, rubber bands, ACE bandages -- they all seem to do well in their place.  I do have some small C-clamps and those giant hand-clamps, because they work.
Title: Re: Ercoupe Build (slow)
Post by: john e. holliday on June 11, 2018, 09:42:42 AM
Yes, I have used that type clamp as well as masking tape. D>K
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on June 16, 2018, 12:59:34 PM
More progress -- the left tip hoop is installed, now I need to make the ribs & put them in (yes, in that order -- this is a consequence of just tossing it together instead of designing it first -- the ribs will be sorta copied from the R side, and sorta just cobbled together.  I also need to figure out the leadouts).

Note that there are FOUR splices on this thing -- there needs to be a scarf splice on the bottom spar so that it can break up to match the slope of the tip -- that part's hunky-dory.  But I didn't need to put the pre-cut piece on TOP, requiring a splice, I didn't need to put the bottom sheeting on BACKWARDS (there's a nice pointy end on the inboard side, where it'll get whacked off), and I didn't need to get all cheap and splice the little bit of bottom spar in the middle.

At some point in any project I just declare the thing a concatenation of errors and keep driving forward.  This one is happening a bit early, but it was going to happen sooner or later.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on June 25, 2018, 10:26:10 PM
Starting in on the LE sheeting.  I never like the way it worked the last time, and find some new way to make myself almost happy.  This time I'm gluing the LE of the LE sheeting to the LE (that's easy to scan!), waiting for the glue to cure, then gluing down the rest, possibly after wetting the top.

CA on the joint shown, Tite-bond on the rest.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on June 30, 2018, 09:20:29 PM
Went to put in the LE bottom sheeting and realized that it would go a lot better if I put the control system in first.  So, one control system.  The leadout guide is 1/32" aluminum, so it may be a bit wimpy -- but it's also replaceable.  It'll go on a 1/16" thick plywood plate, surrounded by 1/32" balsa so that I can finish things off nicely.  I'm going to need some sort of an internal guide at the last rib, to keep them from rubbing on balsa, but I think I can just use a section of big brass tube.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on July 02, 2018, 04:42:12 PM
Bottom LE sheeting on the inboard wing -- woo hoo!  Plus the leadout guide mounting plate.  I screwed up and made it 3/16" too short -- it fits from rib to rib instead of overlapping to match the cap strips.  So I needed a bit of extra wood.  I'll sand it down to match the mounting plate.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on July 03, 2018, 06:44:19 PM
I think I'm in love.  I always have trouble with getting the glue joints right on leading edge sheeting.  And I chose to use a scale airfoil on the Ercoupe, complete with a mild 'S' curve in the bottom of the wing that makes the bottom LE sheeting concave.

I'm using Gorilla Glue this time around, and boy am I happy so far.  It's easy to apply with a disposable glue bulb, I know from experience that it sticks well, and because it foams up you don't need much and it fills the inevitable gaps between the ribs and the sheeting -- so even though my joints still aren't perfect, they're at least full of glue and are still reasonably strong.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on July 10, 2018, 09:12:02 PM
All capstrips on, and this finishes off the sheeting on the outboard wing.  I need to sheet the inboard wing center section, and it'll be ready for joining.  Then I can make the fuselage and tail surfaces, which ought to go quick.

Sharp-eyed real scale people will note that I made no attempt to match the Ercoupe structure -- I just made a conventional model wing to the Ercoupe outline.  I'm not sure how much that'll have an effect for profile scale -- it would be interesting to know.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on July 12, 2018, 06:52:43 PM
Wings mocked up for dihedral.  Not yet glued -- I should fix that.  As yet another consequence of a process that goes conceive - build - design, the wings are definitely a bit different from side to side -- sort of like those "identify the differences between these pictures" puzzles.
Title: Re: Ercoupe Build (slow)
Post by: wwwarbird on July 12, 2018, 07:08:54 PM

 There's a wing in that picture?  Oh wait, I think I see it now...  :##
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on July 12, 2018, 09:11:26 PM
And no one pointed out that I'd left off the landing gear blocks.  Fortunately I figured it out before I glued the halves together; unfortunately the cap strips are in place.  So a delay is happening while I get the LG into the wing.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on July 13, 2018, 10:33:08 AM
OK.  Not as bad as it could be, although I'll still need to make the block supports from the inside out.
Title: Re: Ercoupe Build (slow)
Post by: john e. holliday on July 13, 2018, 10:33:43 AM
Another oops?  Wait til you start sanding fuse on built up fuse to discover you left out the tail wheel gear. HB~>
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on July 13, 2018, 10:36:30 AM
If I start sanding on this fuse and discover that I remembered the tail wheel I'll know I'm in trouble.
Title: Re: Ercoupe Build (slow)
Post by: skyshark58 on July 13, 2018, 11:11:46 PM
Ercoupe tail wheel? All the ones I worked on had nose wheels.
Title: Re: Ercoupe Build (slow)
Post by: Avaiojet on July 14, 2018, 08:07:53 AM
Ercoupe tail wheel? All the ones I worked on had nose wheels.

I flew one that had a nose wheel. Almost bought it.

It was an oldie back then, the 70's. Had no rudder pedals.  n~

I had the Berkeley kit.

I'm interested in the Build.

A great aircraft to model!

CB
Title: Re: Ercoupe Build (slow)
Post by: john e. holliday on July 14, 2018, 11:25:04 AM
The Plane I did the tail skid on was Pat Johnsons P-47. HB~>
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on July 15, 2018, 08:58:00 AM
Ercoupe tail wheel? All the ones I worked on had nose wheels.

That's why it'd be worrisome if I remembered the tail wheel!
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on August 05, 2018, 02:56:43 PM
Landing gear blocks in, landing gear wire bent.  If you look closely at the inboard wing, you'll see that there's a hole drilled on the right that's been plugged -- that's because I made that one a mirror of what it should be.  Then I discovered that it would have been a hole lot easier to just make the receiver for the wire out of 1/4" plywood and drill the hole after the fact (this probably wouldn't work as well if I didn't have a drill press - but I do).

I haven't thought through the scale gear leg dressing -- I'll do that later, or I'll just leave 'em off.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on August 05, 2018, 03:02:13 PM
I never did post a pic of my scale subject.  The documentation comes from Airborne Media (http://www.airbornemedia.com/).
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on August 11, 2018, 06:59:50 PM
It's a wing!  My god, but that's a lot of dihedral.  I could make this thing free flight just by leaving out the control system and maybe making the rudders bigger!

I didn't want to think too hard about how to brace the center section, so I just fiberglassed it.  The styrofoam blocks in the back is because I just wrapped the 'glass around the trailing edge, and it couldn't follow the sharp curve on its own -- so I took some foam scraps I had lying around, slit them, and used them as soft-ish clamps.  The epoxy's curing now, I'll find out if it worked tomorrow morning!
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on August 13, 2018, 09:51:17 PM
Wing set aside for now.  On to the fuselage.  I'm equally tempted to just make it out of two honkin' big pieces of 1/2 x 3", or built up a framework out of 1/2x1/2 sticks and laminate on some skins.  Oh, the indecision.
Title: Re: Ercoupe Build (slow)
Post by: john e. holliday on August 14, 2018, 10:39:18 AM
Does this mean you are going to put the wing in a profile ship?   Shame on you, with your talent an expertise it needs a built up fuselage. mw~
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on August 14, 2018, 10:52:44 AM
Does this mean you are going to put the wing in a profile ship?   Shame on you, with your talent an expertise it needs a built up fuselage. mw~

I spent two full months dithering over how I was going to build a full fuselage for this thing (yes, I know -- formers & planks & stop worrying).  Then I decided to just build the @#$% thing as a profile.
Title: Re: Ercoupe Build (slow)
Post by: Chris McMillin on August 17, 2018, 09:12:22 PM
Hi Tim,
I can see that. When I built the Tigercat I simply followed the plans which were elegant and easy, top and bottom keel with outer shape per the scale drawing, left and right keels with cross sectional formers, same deal with outer shape per scale drawings, then plank it with 3/16's x1/8 balsa and sand to shape. It was like building 3 fuselages though!
If you didn't have the cross sections from scale plans that could get involved. One good thing about having a profile first is that you can get a real good idea of ow it flies, how it all works, etc and then building a full fuse version would be easier.
Chris..
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on August 18, 2018, 07:05:04 PM
Don't poke at that little bitty hole in the bathroom floor, don't put a compression gauge on that '63 Suburban you just bought for $600, and don't superimpose a picture of your scale subject on the 3-view.

Sigh.
Title: Re: Ercoupe Build (slow)
Post by: eric david conley on August 18, 2018, 08:33:08 PM
     Hey Tim, when I look at your picture that you imposed the three view over I see that the picture was taken several feet (well maybe 1.5') above where middle of the fuselage is on three view. I don't think you can use a photograph that is taken eye height (standing) to get the prospective you would want to build a profile.  (maybe?)
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on August 18, 2018, 08:44:20 PM
     Hey Tim, when I look at your picture that you imposed the three view over I see that the picture was taken several feet (well maybe 1.5') above where middle of the fuselage is on three view. I don't think you can use a photograph that is taken eye height (standing) to get the prospective you would want to build a profile.  (maybe?)

I could have done a better job extracting the picture, but I was lazy.

It's really the shape of the canopy -- the 3-view has it straight in front and bubbled in the back, while the real plane has a bubble in the front and straight in the back.

Yes, you can't make too many judgement beyond that.  But isn't that enough?
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on September 22, 2018, 05:56:36 PM
Super tiny bit-o-progress -- I got the arrangement of wood in the nose figured out.  Three engine bearers (I had been thinking of going electric, but changed my mind) and the nose gear bearer.  As part of that, I figured out a nose gear arrangement that'll give me some spring without having to make anything too wacky.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on September 22, 2018, 06:01:19 PM
I'm going to steal the general idea for the nose gear from here (https://stunthanger.com/smf/building-techniques/fancherized-twister-build/msg279104/#msg279104), except that the retainer block will need to be toward the back, because the landing forces will tend to want to pull the back of the wire out, rather than the front.
Title: Re: Ercoupe Build (slow)
Post by: Chris McMillin on September 23, 2018, 10:26:47 PM
Keep at it, man!
Chris...
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on September 29, 2018, 12:45:19 PM
OK.  So this is utter insanity.  Working on the front landing gear, making a yoke for the wheel.  I'll make a steel collar for the top, then braze the music wire LG to the yoke.  The axle will go through a pair of 1/8" holes in the bottom of the yoke.

Even for all the work, it only sorta-kinda looks like the original, and will probably not look quite right from 10 feet away -- I just wanted an actual yoke holding the wheel, and hopefully it'll make a better impression than a hook bent out of music wire.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on September 29, 2018, 02:49:23 PM
I love it when a plan comes together.  Ready for brazing.  Of course, we won't know for sure how good it is until the first hard landing...
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on September 29, 2018, 05:17:50 PM
And brazed.  I need to get better at using less filler -- I think I need to ignore the directions on the can of flux, and apply flux directly to the part.  If I brazed more than once every two or three years, I'd probably be better.

The two white circles are spacers to hold the wheel centered in the yoke.  They're hand machined from solid billet cutting board.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on September 29, 2018, 07:43:13 PM
Clamp made, mounting block drilled for clamp, T-nuts in (and I need to order more 3/4" screws!)  It's ready for glue.
Title: Re: Ercoupe Build (slow)
Post by: john e. holliday on September 29, 2018, 08:16:53 PM
Looks good to me.    H^^
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on October 03, 2018, 11:41:39 AM
Fuselage framing in progress.  I'm going with an open framework for the rear fuselage, to be sheeted with 3/32" balsa, in hopes of getting the weight down.  Later on, when I complain about putting a ton of brass in the tail, you may all laugh and laugh.

Motor mounts and nose gear mount is in place.  I'm planning on fairly small 3/32" plywood braces that glue directly to the maple, with the balsa sheeting butted up to that.  Then I'll use honkin' big lite-ply doublers of more traditional extent over the top -- should be strong enough for stunt, & so strong enough for scale.

The bottom stick is some high-density (13.5 lb/ft3) that I had lying around -- I'm getting rid of it!  Too bad it's all behind the CG.  It needed to be bent -- it turns out that a 1/2 square piece of balsa fits nicely into a tall beer bottle filled with water and ammonia.  If you look closely you can see the water mark, about 1/5 of the way in from the right edge of the picture.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on October 14, 2018, 08:21:10 PM
Fuse frame mostly done (there's some shaping to be done around the dashboard).  Then it gets doublers -- which I haven't fully figured out yet, because I want it strong, but I also don't want it to weigh a ton.  Then it gets sheeted with 3/32" balsa.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on October 27, 2018, 08:58:49 PM
I was kind of unhappy about using a 40FP or 4xLA on this because the only one I have that's not mounted on a plane is one that's been modified for stunt, and I have no idea how well it'll work with a throttle on it (it's certainly down on power compared to my other similar engines).  So I was digging in my engine drawer and came up with a pair of old Fox 40's in a box.  One of them even runs.  Woohoo!  I don't have to cannibalize a plane!  And I have junker engine (the front end leaks) to use for fitting up!

They're way bigger than the OS bushed 40s.  Fortunately, I had been planning on using motor mount pads anyway, so I just made a different set of pads.  The engine fits, after a very slight trimming to the bearers, and a lot of trimming to the pads.  The best part is that if it doesn't work out, a 46LA, 40LA, 40FP or whatever will go in there with a different set of pads.

The nose is going to get doublers and triplers -- I've cut out fairly small doublers out of 3/32" plywood to tie the engine bearers and the front landing gear mount together.  I just couldn't bear to make a giant doubler out of that heavy plywood to go back to the wing, so once I sheet the fuselage I'll put 1/8" lite ply triplers over the nose back to about the high point of the wing.  That should make a strong-enough front end as long as I don't make a habit of unscheduled contact with the ground.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on October 28, 2018, 05:07:31 PM
Outside nose doubler glued & clamped with gravimetric clamp.  I used epoxy mixed with an equal volume of microballoons, to tone down the weight without (hopefully) getting weaker than the wood it's glued to.  Once this is cured I can start fitting the main fuselage sheeting (actually, I can dive into the work-week and make little progress, but that's life).
Title: Re: Ercoupe Build (slow)
Post by: Gary Dowler on October 29, 2018, 01:01:29 AM
Looking good, Tim. You going to have it at Roseburg ?  I'll be there, perhaps we can meet in person.  Hoping to have my first scaleproject ready, a PT-26. PT-19 with a canopy, and Canadian license plates.  It's progressing slow though.

Gary
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on October 29, 2018, 08:35:49 AM
Looking good, Tim. You going to have it at Roseburg ?  I'll be there, perhaps we can meet in person.  Hoping to have my first scaleproject ready, a PT-26. PT-19 with a canopy, and Canadian license plates.  It's progressing slow though.

Well, I'm not sure if it'll be ready for Roseburg in 2019, but yes, I'll have it at the regionals sometime.  Now that I'm part of the corporate machine again I don't have a lot of time to build.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on October 29, 2018, 07:14:20 PM
Here I go -- the most foolproof way I've found to make sure I'll never need tail weight.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on November 04, 2018, 02:04:38 PM
Putting the sides on the fuselage.  So far the fuselage weight isn't too bad -- if I'm doing my ciphering correctly I'm up to what it would be with 1/2" think 8-pound wood, and because it's built up it's much stiffer.  Overall thickness at the moment is 11/16" or so -- I'm allowed an inch, so I'm OK there.

If you look at the bits laid out you'll see that it's in three pieces, with a tapered piece in the middle.  That' partially because that's what I needed to do to get it to fit, but partially because I had one really heavy sheet of 3/32" balsa -- 11.8 lb/ft3.  So I whacked it into two tapered pieces to go on each side of the fuselage.  I'm hoping that'll make a nice balanced assembly, with the heavy stuff put right where its strength contributes the most to stiffness.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on November 04, 2018, 08:00:10 PM
And the triplers!  I only weighed them to torture myself.  The inside tripler (on the top) has a nice layer of Titebond on it, because I put glue on the wrong @#$% side, then scraped it off and tried again.  Oh well; hopefully the covering will stick.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on November 10, 2018, 01:43:28 PM
Fuselage assembled, edges sanded, wing cutout cut and fit to the wing.  It's almost time to start running around in the driveway making airplane noises and annoying the neighbors.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on November 11, 2018, 07:05:25 PM
Tail feathers.  All that's missing from the main structure is the canopy (which is going to be interesting because it's so big and skinny; see this thread (https://stunthanger.com/smf/building-techniques/home-brew-canopy-for-profile/))
Title: Re: Ercoupe Build (slow)
Post by: Dennis Saydak on November 16, 2018, 06:13:25 PM
Congratulations Tim on a really nice project and build. It's looking great!
Looking forward to seeing the finished model. It will be distinctive in the air.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on December 02, 2018, 02:11:34 PM
Canopy plug done.  Now I just have to figure how to wrap it in plastic.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on December 09, 2018, 01:04:45 PM
Epoxy/microballoons on the wing root.  The goobered-up side is epoxy glue + microballoons, in a cold shop.  The nicer-looking side is finishing epoxy + microballoons, except that I didn't notice until I edited the photo that there's a ridge that I didn't wipe away when I was applying the stuff -- probably because I was distracted by trying to save the goobered-up side, instead of just scraping it all down to bare wood before the glue dried, and doing it over again.

Ah well, the bottom side is at least as good as the good half of the top.  And lots of careful sanding should take care of the boogers, even on the part that's goobered up.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on January 05, 2019, 02:46:26 PM
Much sanding on the wing root later, and various distractions, I actually got a coat of dope on the wing!  In the process I noticed that I hadn't gotten around to building the surrounds around the landing gear mounts -- oops.  Oh well; easily remedied.  I got the trough between mount and LE sheeting filled, and stubs of capstrips installed, and some scraps of 1/4" square put behind.  Everything was glued in to stand proud by about 1/32", then sanded back to match.  It's not as smooth as I'd like, but I'm in the "just get it done" phase of construction, so I'll live with the inevitable divots around the gear (and try to figure out how to prevent that in the future!

I really ought to get the LG clamps done now, too -- I'm planning on 1/32" plywood or aluminum, screwed to the LG mounts.  That way I can paint 'em to match the rest of the model.

Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on January 11, 2019, 11:53:14 PM
Two more coats of dope!  And then I realized that I don't have a weight box in the outer wing.  Dangit.  Yes, it's scale, I should just put an ounce or two out there.  I think it'll get a weight box anyway.
Title: Re: Ercoupe Build (slow)
Post by: Will Hinton on January 20, 2019, 12:48:05 PM
I would definitely do the weight box.  A wing hanging low or riding high would drop your flight score with most judges.  I'm enjoying this thread, Tim, don't leave us hanging!
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on January 20, 2019, 04:10:25 PM
I would definitely do the weight box.  A wing hanging low or riding high would drop your flight score with most judges.  I'm enjoying this thread, Tim, don't leave us hanging!

I've been working so hard I've been forgetting to post!

I got a weight box whipped up.  I normally size my weight boxes for a single pile of standard 1/4" washers, with a screw going through the middle to hold in washers and lid.  The space I had was shallow, and I was afraid I may not have enough room.  So this one will hold two piles of those washers, with a lid that screws on in the corners.  Should be plenty heavy, if needs be.

Bottom picture is the canopy blank.  It turns out that Zirolli Scale Models will at least look at your canopy blanks and assess whether they can pull a canopy or not.  This one's deep and narrow, and I've gotten conflicting suggestions on whether it needs draft (including from my own experience in pulling fiberglass parts off of similar plugs -- I'm pretty sure I could wax that up and pull a part off of it, as long as the part was thin enough that I could flex the sides out).  Rather than trying to sand a bunch of draft into it after the fact (which would make the canopy narrower) I'm going to send it in as-is, and I'll either get a canopy and be done, or I won't and I'll work up another plug.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on January 20, 2019, 08:19:53 PM
Weight box hatch cover.  This is going to be a pain to pull out each time, so I'm gluing a 1/8" diameter by 1/16" thick neodymium magnet into the cover and the box, rigged so they push each other apart (I hope -- we'll see if I got it right when I'm done).  That way when I unscrew the cover it'll tend to pop up.

Not mentioned in my last post, or shown, is the fact that the empennage is nearly covered -- both vertical stabs and the horizontal stab are covered, the elevator is half covered.  Covering is lightweight silkspan that's been in my possession for 40 years, traveled from Oregon to Massachusetts and back, all waiting for me to finally cover another plane in silkspan.  The wing will get medium-weight, or it'll get polyspan (I should do polyspan, but I've got all this silkspan...)

Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on January 26, 2019, 02:35:11 PM
Got the top of the outer panel silkspanned.  Of course, I only realized when I started posting this that I don't have the weight box hatch cover sanded to size, so now I'm going to make an awful mess of the inside of the wing.  @#$%.  I thought I'd covered up the weight box, but I was working on the inboard wing.  Which I should have realized, but didn't because the way I did the leadout guide leaves the leadouts very nicely tucked into the wing until I need them, and then I'll pull them out with a hook.  Man, you think hard all week at work, and then on the weekend you try to relax, and look what happens!
Title: Re: Ercoupe Build (slow)
Post by: Will Hinton on January 27, 2019, 04:12:36 PM
(quote) Weight box hatch cover.  This is going to be a pain to pull out each time, so I'm gluing a 1/8" diameter by 1/16" thick neodymium magnet into the cover and the box, rigged so they push each other apart (I hope -- we'll see if I got it right when I'm done).  That way when I unscrew the cover it'll tend to pop up.
(quote)

Now THAT is darned clever thinking! H^^ H^^ y1
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on January 27, 2019, 05:38:24 PM
Now THAT is darned clever thinking! H^^ H^^ y1

I thought of it a few years ago.  Here's a video of the last one.  It's not in service yet -- my shoulder went out and I thought I wouldn't be able to fly stunt again, so I started this project.  Now my shoulder's better, but dangit, I'm going to finish this project!

Note that for it to work the thing has to be very free in it's mount -- it's made to have generous clearance all around, and I'll make sure to wax the back of it so it won't stick paint to paint.

https://www.youtube.com/watch?v=vqxhgp0j5vc
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on February 01, 2019, 08:40:54 AM
I just got word that Ziroli models was able to pull the canopy on my form!  So that's a worry that I can put to rest.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on February 01, 2019, 08:41:33 PM
Three canopies for the price of two (well, one looks very "test pull").  All the sanding scratches, dents, and other imperfections in the plug have been faithfully reproduced, so kudos to Ziroli Plans for that.  It's better than I expected, and I couldn't be happier.

I'll use the rattiest one for fitting to the fuselage, and only take the best one out of wraps when it's time to glue it on.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on February 02, 2019, 11:38:36 AM
The way-preliminary canopy test fit looks good.  It needs some trimming in front, so there'll be more overlap than is apparent here.

Unfortunately, I realized that I cut the hole in the fuselage to match the canopy profile, which works everywhere but the front -- I need to put a dashboard in there, for me if not for the class rules.

It's really kind that Ziroli sent me the reject canopy -- that is so nice for fitting up.
Title: Re: Ercoupe Build (slow)
Post by: john e. holliday on February 02, 2019, 01:43:10 PM
That is great they would do this for you.  Probably worth every penny. D>K
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on February 02, 2019, 03:05:54 PM
That is great they would do this for you.  Probably worth every penny. D>K

Oh yes.  I was seriously gathering information about doing my own vacuum forming on that scale -- the 'reject' canopy I got is probably better than what I would have done, and it would have taken me days of work.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on February 02, 2019, 06:38:51 PM
Someone forgot that airplanes usually have control panels, that are visible through canopies.  It's not really a scale outline thing (as far as I know, this'll be my first scale competition), but I wanted it.

Narrower than the fuselage on purpose, to account for the fact that on a rounder fuselage, the dash isn't hard up against the canopy.  I'll probably have some filler in there too.

Glued with Gorilla Glue, because I know the gap isn't right.  Will probably back it up with a bamboo skewer, to save me from the potential embarrassment of a part rattling around inside of a nicely finished canopy.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on February 03, 2019, 05:45:00 PM
Dashboard pegged in with two 3/16" dowels, installed through the same hole in the dash, but at different angles.  Yes, it is vast overkill.  But I always sneer at people with stuff rattling loose in their cockpits; no way am I going to commit the same error!

And a canopy fit check.  I am so, so glad that I decided to do a canopy rather than just paint one on -- even if the rules don't require it (I just double-checked) and it's adding time and expense to the build.

I'm looking at the prototype again, and I see that if the seat back is visible from outside it doesn't stick up far (the photos I have show someone's jacket tossed over the seat.  The package shelf behind the seat, however, is definitely higher.  So the thing may acquire another block-o-wood in there.
Title: Re: Ercoupe Build (slow)
Post by: Will Hinton on February 07, 2019, 07:27:56 PM
This is looking top notch!  I'm lovin' it.
Title: Re: Ercoupe Build (slow)
Post by: wwwarbird on February 07, 2019, 08:14:07 PM
I just got word that Ziroli models was able to pull the canopy on my form!  So that's a worry that I can put to rest.

 Did I miss something here? Does Ziroli do this as a service?
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on February 08, 2019, 10:05:47 AM
Did I miss something here? Does Ziroli do this as a service?

Yup
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on February 10, 2019, 05:10:50 PM
Experimenting with paint.  Got some advice to sand the outside of the canopy & apply clear dope; here's my first semi-successful results.  This is clear over a surface sanded with 600 wet, and another one with 1500 wet (I was told to use 1000, but I seem to be fresh out).

It's not quite as clear as the original stuff (on the left for comparison), but it's not color sanded or rubbed out or anything.  I think it'll do, since there's not going to be a cockpit interior anyway.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on February 18, 2019, 07:25:10 PM
After letting the dope cure for week (while I was just barely healthy enough to report to work, work, get home, and sleep), the doped-over canopy material looks pretty good.  So, I have that part covered.

I decided to 'glass the fuselage with 1/2 ounce cloth, both to get a nice easy finish, and because it makes it all-over fuel proof.  I think I'm not a fan of fiberglass cloth, but what the heck.

The two weights are before I started adding 'glass, and the weight after the cockpit and one side was done, but not the other.

It's now sitting on my bench with the epoxy slowly curing.  I need to bring it in here.  And -- oh ****!  I need to wipe down my scissors with solvent!  I forgot last time, and had to scrape the epoxy off with a knife, to the detriment of the knife, and probably the scissors, too.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on March 02, 2019, 07:28:32 PM
Been busy and under the weather, and sanding is boring.  So not much to show.

It's been sanded to a fair-thee-well.  I just painted it with nitrate, and put on putty to fill the low spots.  Yes, I'm probably committing a sin to use lacquer putty for this, but I grew up in a body shop and it just seems natural.  The long swipes of putty are because there are some long skinny low spots where the sheeting joins -- clearly I need to up my game when it comes to joining sheeting.

The plan is to fill the serious divots, then go with a couple of coats of dope + zinc stearate, then sand, then get back to covering the wing.  I want to get all the bits fairly well finished before I assemble, then I'll spray with silver (and probably exclaim in dismay), and finish up the finishing.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on March 03, 2019, 02:55:05 PM
Sand, examine, curse, fill, let dry, repeat.

The circled area is a particularly frustrating divot.  I forgot to change out the waxed paper on my bench after 'glassing the fuselage.  The divot under that filler was from pressing the thing into a dried drop of epoxy.  D'oh, d'oh, d'oh, and in French, for emphasis, t'oh.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on March 10, 2019, 05:15:40 PM
No picture, because the contrast between tissue (yes, tissue) and balsa isn't at all high.  I'm repairing the divot in the repair of the divot in the repair of the shortcoming in the original construction that left divots in the fuselage skin.

One of the low spots was bigger than I thought.  So I filled it, with some cursing and sanded it flat (dammit!).  And, sanded through the fiberglass in four spots surrounding the divot.  So I covered that with tissue, silently accepting that there would be one odd rippled spot in the finished product.  As of last night I had decided to go into full "FIFI" mode (F*** It, Fly It) -- then I noticed that I had sanded through the tissue into the balsa along the ridge where two sheets of balsa join (which joint was the cause of the first divot).  So I'm @#$% well going to fix that, and then I'm going to declare it FIFI.  Or I'm going to start collecting empty beer bottles, or something.

Grr.

Still hoping to make it to the Regionals...
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on March 13, 2019, 10:35:30 AM
No picture, because the contrast between tissue (yes, tissue) and balsa isn't at all high.  I'm repairing the divot in the repair of the divot in the repair of the shortcoming in the original construction that left divots in the fuselage skin.

Gouge out the divot, lay down a 1/2" by 3" strip of Esaki, dope, sand, putty, sand, more putty dammit, sand, and dope.

OK.  Now I'm just going to put on the filler and sand.

With my eyes closed, so I can get this plane done.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on April 27, 2019, 12:02:04 PM
Note to self: never, ever, sand a profile fuselage with an idiot board* once you've started finishing it.  The patch didn't work.  I've been distracted by paying work, but over the last week or so I scuffed up the remaining coating (probably 90 to 95% of the surface still has glass on it), and I've covered it with good ol' silkspan.  So the finish on the fuse is basically a kinda good idea at bottom, then a terrible mistake, then an attempt at a fix, and then a fix that may be adequate.

But, if you're at the Regionals and you see a scale plane in the circle trailing streamers of its fuselage covering -- that's me, with adhesion problems.

* At least, that's what they called flat sanding boards in my dad's body shop.  Can't imagine why...
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on April 27, 2019, 02:36:00 PM
Engine "compartment" mockup and balance mockup.  That boat anchor in the front is a Fox 40.  The big weight over the wing opening is about three ounces heavier than the current wing (nearly 10 ounces, and I only have half of it in silkspan, and roughly at the wing's CG.  The nut about halfway back is an ounce of weight to simulate finish weight.  The pen about 15% back from the wing LE is the balance point.

So it looks like I'm in the ballpark, although I suspect that in the end the weight box in the back will remain empty, and I'll be scratching for space to put weight in the front.  But I'll roll with what I get.

Too bad the AMA won't let you use metal props -- I could get one made out of brass; that'd bring the CG forward nicely!

Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on May 27, 2019, 11:38:35 AM
As a couple of you noticed, I did not have an Ercoupe at the Regionals.  Here's the servo installed.  I'm going to put all the radio equipment on the in-circle side of the nose, with the servo lead coming through a slot that goes from the servo mount.

I realized about three weeks ago that (A) I needed to enclose the radio equipment, and (B) time was short, so I came up with an ugly box to put it in.  I'm going to replace that with something nicer (but keep it as a backup, just in case).  Current thought is trending to something that looks sorta-kinda cowl like, and screws onto the left side of the nose.  That should provide easy access to the radio, and look better than the crate that I have built.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on May 27, 2019, 07:55:27 PM
Progress on the fake cowl radio box.  It's ready for planking.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on May 29, 2019, 10:53:53 AM
Oh, so that's why I don't plank.  Right.  I forgot how freaking tedious it is -- at least, when I have to watch the clock and cannot just lose myself in it.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on May 30, 2019, 10:41:23 PM
Planking proceeds, ploddingly.

A bit faster once I got around the tightly curved part and started using half inch wide strips.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on June 01, 2019, 11:17:53 AM
Oooh, this looks much nicer.  Finishing this is going to make me want to finish the plane, not throw it in a dumpster.

I will need to un-round the edges of the fuselage where the box is, though -- there's some epoxy/microballoon mix in its immediate future!
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on June 01, 2019, 02:08:21 PM
Test fit radio.  As a bonus, there's much more room than in the ugly box.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on June 01, 2019, 10:09:32 PM
First, if you guys notice me doing something stupid, like, say, building a plane that doesn't comply with the rules, then by all means speak up!  Part of doing a build thread is so that folks can point out that I'm on the wrong track.  The stunt guys have absolutely no problem with this, BTW.

Second -- I can't make the fuselage wider than 1 1/2" in profile.  Dangit.  So the radio needs a different home.  It'll fit -- barely -- into the wing, so that's where it's going to live.  My first big problem is routing the servo wire.  I have some phenolic tubing that I bought a long time ago for coil forms for radios.  I've used maybe two inches worth of it, so I can use a four inch piece for a wire guide, right?

So, one wire guide (which doesn't intersect the bellcrank which, thankfully, lives entirely in the left wing panel), and a hole drilled in the fuselage to intersect with the wire guide and the well for the servo.  Voila -- the servo wiring can be done.  There's a picture of the test fit.  As long as I don't goober that area up with glue when I assemble the wing to the fuselage, I should be fine.  I'll probably make sure to insert a pull string.

Third try at a radio box -- woo hoo!  OK.  some things go easier if you draw up detailed plans first.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on June 30, 2019, 01:31:22 PM
Here's a bit more on the radio box.  Because I didn't plan ahead, I needed to drill a hole in the already-completed fuselage.  Had I planned ahead I would have done it before the plywood doublers went on -- oh well.  Drilling the hole after the fact means that I have this hole in the very bottom of the fuselage that I need to fill.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on June 30, 2019, 01:33:38 PM
And -- I got the other half of the wing covered.  Finally.  I need to patch the silkspan over the plug for the radio wiring hole and paint the cockpit area with flat black.  Then I just need a few more coats of clear and I can start in with the sanding sealer already.
Title: Re: Ercoupe Build (slow)
Post by: Chris McMillin on June 30, 2019, 04:50:20 PM
Cool man, keep on truckin'.
Chris...
Title: Re: Ercoupe Build (slow)
Post by: Will Hinton on July 02, 2019, 09:47:48 AM
I'm lovin' it!!! H^^
Title: Re: Ercoupe Build (slow)
Post by: john e. holliday on July 02, 2019, 11:18:27 AM
Keep up the good work.  Also thanks for making the mistakes for us.  Nothing like experience. D>K
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on July 02, 2019, 11:31:28 AM
Keep up the good work.  Also thanks for making the mistakes for us.  Nothing like experience. D>K

Learning from your own mistakes is good.  Learning from someone else's is much, much better.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on July 02, 2019, 11:34:38 AM
Keep up the good work.  Also thanks for making the mistakes for us.  Nothing like experience. D>K

Overall, I'm having fun with this build.  My day job is product design, where you have to sweat every detail long before any metal is cut or bits downloaded onto processors (because when you have to do the sort of "oops, gotta throw that away and start over" mistakes it means that 1000 units have to be reworked).  So just launching into a build without thinking about every freaking step ahead of time is kinda nice, even if I've probably done enough rework to account for mild to middling crash.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on July 07, 2019, 04:11:20 PM
I'm literally papering over my errors.  I had to plug the hole in the bottom of the fuselage from drilling up to the servo box, and I had to plug the hole in the side of the fuselage from my plan to have a radio box as a cowl (which would have been illegally wide).

Both were plugged with balsa glued in with Super Fil, both have been doped, and both have been covered with paper -- Esaki in the case of the side hole, and silkspan in the case of the hole on the bottom.  Sand, paint, sand, paint...

I'm hoping that covering the small divot with Esaki is a good idea.  It does seem to be getting shinier faster than the silkspan; we'll see what the long term results are, well, in the long term!
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on July 07, 2019, 04:18:27 PM
Sand, paint, sand, paint.

I think I'm going to spray on the last few coats of clear -- it should go faster, and be smoother.

My overall strategy for this is to finish getting enough clear on, then finish out the cockpit, then install the canopy, then put on sealer, then sand as individual bits.  Once I'm happy, then I'll assemble the plane (yay!), and finish out the fillets and any bits & bobs.

Cockpit "finish" is just going to be flat black -- if I'm reading the rules for the event right I don't need any detail at all, and the way that I've cut out the interior of the cockpit should look pretty close to an empty airplane from the side.

After all that, I'll put a coat of silver on it (remember, this is my practice for doing a Stunt Finish), then I'll probably be depressed for a few days, since the silver will do such a good job of making all of the mistakes apparent.  Perhaps I'll take up skateboarding or golf.

Once I get over that and return to modeling, I'll scuff up the silver and paint it white, then put on the trim.  Easy peasy.  At the rate I'm going, maybe I'll make the next Regionals!

The pictures show the sum total of my modeling efforts for today, which was to make a mount for painting the fuselage, that uses the engine mounting bolts.  It's made out of scrap aluminum, but I've seen people use all sorts of things.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on July 14, 2019, 09:19:13 PM
The last coat of clear was shiny when it dried! I think I'm pretty much done filling the grain of the silkspan!
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on July 17, 2019, 10:52:18 AM
More random bouncing around in the build order.  Since the fuselage seems ready for the fill coat, it's time to "detail" the cockpit -- which for this plane means painting it flat black.

I wanted to have a vent to the outside, to minimize the puffed canopy effect.  I also wanted to do it without filling the cockpit with castor.  For sport planes I usually just drill a tiny hole in the back of the canopy -- this time I decided to drill another unscheduled hole in the fuselage, and vent the thing out through the wing (which will get a matching hole, and I'll have to be careful not to fill it all with glue when the wing goes in).

And because I hope to keep the balsa dust out of the canopy (insert hollow laugh here) there's a filter.  It's just a bit of Q-tip fluff glued into a section of aluminum tube, but as long as it passes air and not balsa dust, I'll be happy.

The canopy paint was a lovely collision of screw-ups that turned out right: I wanted flat black, but didn't have any.  The can of black dope that I got from a friend is dry.  But I have this 20-year-old bottle of Aerogloss, that's been thinned with regular lacquer thinner.  I'd never trust it on the outside of a plane -- but inside a canopy should be safe!

So I unlimbered my new (to me) air brush, and sprayed it on expecting shiny.  Because it's in such crappy condition, I got flat black!  If I'm lucky, it won't all flake off the first time I start up the engine.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on May 19, 2020, 08:50:12 PM
Well, it's been less than a year.

Canopy glued in.  All the previous pictures have been with the "trash" canopy.  I got the "good" canopy out of the stash, scuffed up the inner edge around the perimeter, and glued it is -- with some work.

It's glued in with epoxy that has some crushed charcoal mixed in for color, so that it doesn't show against the black of the cockpit interior (it's a boring cockpit). 

I was paranoid about smearing all that dark black glue on the inside of the canopy, so I made a scissors-action spreader by taping a stick of wood along the bottom outer edge of each side of the canopy, then taping sticks onto the canopy so I could squeeze them and spread the canopy -- and it works!  The third picture shows the canopy spread out ready for installation.

The final picture shows the canopy all glued down, clamped firmly, and waiting for the glue to dry.  I messed up the contour of the back of the canopy vs. the fuselage.  It would have been better to work over the fuselage more -- instead, I just clamped the canopy in place.  The second picture shows a clamp stop that prevents the clamp from slipping.

So tomorrow I can take the clamps and tape off, and see how much balsa dust there is inside.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on May 20, 2020, 01:08:53 PM
Tape off.  Just a few minor boo-boos.  I think I'm going to try the black glue method again at least once, but it does have the obvious (if only in hindsight to me) flaw of not having a way to rework smears & errors on the inside of the canopy.  The really bad one is an area that was going to get painted anyway; there's a smudge where I started with the canopy too low and then brought it up; for that one I'll probably just cheat the beltline of the cockpit up a bit from scale (it's not like I'm expecting to win).

There's definitely some smudges on the outside that I'm going to need to deal with -- for those, if the beltline doesn't cover it I'll probably go over the thing with fine sandpaper and polish out the resulting scratches.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on June 08, 2020, 09:02:19 PM
Various voids in the first cut of gluing have been filled, sharp edges sanded, and a layer of dope applied to the raw epoxy.  There has to be a better way to do this...

Once it's as smooth as I have patience for, I'll mask it off and paint a strip of black to define the canopy.  This violates the "darkest color on top" rule of painting -- but from the inside of the canopy, it will be the topmost coat.  Hopefully the silver will mask it (or gray, if I do this the Phil Granderson way).
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on June 09, 2020, 10:06:11 AM
This is out of order of the actual build sequence, but I realized I didn't have a picture of it.  Here's a shot of the leadout guide mount on the bottom of the wing.  The pic is a bit too close to show context, so the included shots are that context.


(https://stunthanger.com/smf/scale-models/ercoupe-build-(slow)/?action=dlattach;attach=287133;image)

(https://stunthanger.com/smf/scale-models/ercoupe-build-(slow)/?action=dlattach;attach=287246;image)
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on July 01, 2020, 05:39:37 PM
Paint, sand, paint, sand.

I'm probably doing this out of order (I said I'd do the black surround on the canopy), but I'm starting the build up on the fuselage.  I'm using someone's suggestion to put a bit of white in the clear, to give a bit of cover.  Which means that I really should do that black surround sooner than later...

It's actually looking like it may end up smooth and shiny, possibly before the 22nd century.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on July 09, 2020, 07:03:24 PM
Look!  A wing!  I've only got about a square foot sanded on the first coat, but it's coming along well.

(In case anyone's wondering -- I purposely chose a scale subject with a shiny new paint job, because the other reason I'm doing this is to practice a Stunt Finish.  The project is just taking longer than I thought it would.)

Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on August 01, 2021, 09:08:33 AM
Paint, sand.  I got everything covered and was going great painting & sanding, then got too enthusiastic & sanded through the silkspan in spots.  That, plus a couple of puncture wounds in the wing got me so disgusted with myself that I put it up for a while.

Back to it -- it'll be a patchwork underneath, but hopefully it'll look good on top.  And I'm slowly (very slowly!) learning not to sand through the silkspan.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on August 05, 2021, 01:28:31 PM
The current project phase is "get this plane out of my shop!"

Posting a picture of one of my building surfaces -- I love doing final assembly on glass, because -- flatness.  It seems that the standard assembly/paint sequence is to get the plane all assembled earlier in the process than I have.  But I'm almost there with the assembly, and I have this fear of ripping a rudder off while sanding it. 

I'm probably going to get the rudders married to the stab and the wing in the fuse, then do a few coats more finish before putting stab & fuselage together.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on August 05, 2021, 05:28:19 PM
Gluing the fins onto the stab.  1-2-3 blocks seemed a nice way to get right angles.

I'm using SuperFil, because (A) it ought to be strong enough, and (B) the far side of the elevator pocket in the rudder is just covering material; I wanted to fill that hole up nicely without having lots of goo dribbling out of the rudder holes.

If the rudders come off in flight, I'll know it was a bad idea.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on August 06, 2021, 06:33:21 PM
Well, it's not quite ready to go fly around the shop.  In fact, the wing is freshly glued, and I shan't touch the plane until morning.

The second picture shows the wing ready for glue.  This is a technique I learned from someone here -- you glue the wing in just three places each, top & bottom, with "dots" of epoxy.  That's more than enough to hold it on, and in the unlikely event that you need to tear the plane apart, it's just those six strong points that you need to saw off.  Which I'll then defeat utterly by putting on an epoxy-microballoon fillet.

The last picture shows a good part of the wing all set up, ready for glue.  The fuselage has notches filed into it so that I can inject glue into the wing-fuselage gap.  The wing is pinned at the spar on both sides to locate it laterally in the fuselage.  The fuselage is wedged (you can see one of the wedges sort of between the back two glue stations; there's one on the other side).  The wedges keep the fuselage upright with respect to the wing (you can see the square I'm using as a reference).  Not shown are the fact that the wing is blocked up level, with styrofoam blocks about halfway out.  Also not shown are little tick marks on the wingtips, at 28 3/4" out from the fuselage -- these are my reference for measuring the wing for squareness with the fuselage, by measuring the triangles from the stabilizer platform to the tick marks.

For glue I used epoxy with just enough microballoons so that it won't dribble out of the wing joint.  I used a syringe to inject the epoxy into the holes; it looks like I have nice little pads about 1/2" in diameter on all three of the top glue points -- I'll glue the bottom tomorrow, after the top has set.

This thing is as square as I can get it, the glue is setting up, and as long as there's not an earthquake, it'll be that way in the morning, too.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on August 07, 2021, 01:18:39 PM
Fillets on Ercoupe rudders is definitely not scale -- but it needed fillets there, or I needed to bolt the fins on (which is what the original did, with a cute little bracket that shows from the outside).

I'll find out just how "too tight" these are in a year or two, when the finish either does or does not bubble up.  I have a model that I got from a friend, that has practically no fillets on the rudders and which isn't showing signs of problems.  But then, that model has too much plasticizer in the dope, so maybe it's not a good example?
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on August 08, 2021, 07:29:19 PM
More non-scale fillets.  I'm not going to try to do the trailing edge fillets that should be there (Walter, pay attention -- you can use that against me).

It's almost like some Stunt guy is attempting scale...

At any rate -- I realized part way through that I was using a skill that my dad taught me; to make a sweep out of a bit of trash sheet material and use that to make some profile.  He used it for fiberglass work on cars; I'm using it here.

Stuff's put on rough with a stick, then swept to mostly-round, then finished off with a finger dipped in denatured alcohol (I wear a rubber glove, cuz -- epoxy).  The alcohol is very compatible with epoxy, and will, hopefully, be flashed off before it has a chance to screw up the cure of the epoxy.

I probably added 10-12 grams to the structure (oh no!) -- but it's a half an ounce of curvy prettiness, so I'm not complaining.

Tomorrow it'll be back to sanding and painting, on the fuse-wing assembly and on the tail assembly (they're not yet married because the more I assemble the thing the more delecate it'll get.  Although I'm thinking that if I'm really careful with the glue joint, no fillet at all would look more scale than a tail with a fillet.  Hmm -- gotta think about that).
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on August 14, 2021, 07:17:57 PM
I've been juggling how many scars I want to finish at the last step of the game vs. how much I don't want to sand on those rudders when they're attached to the plane (the sound of "crunch -- @$#%!" is running through my head).  It's past time.

Stab's on.  Measured every which way, and installed.  Glue's on, and no doubt setting up at a sprightly pace, because it's over 90 outside, and probably above 80 in my shop.

I got to this point and realized I really didn't have a nice way to clamp it up.  Fortunately, someone (probably stunt-obsessed) decided that this scale plane needed a weight box in the tail.  Even if it never gets weights in there, it's a delightful place to put a clamp -- so, I'm happy with past me.
Title: Re: Ercoupe Build (slow)
Post by: john e. holliday on August 15, 2021, 03:39:35 PM
Haven't checked on this til today.   Like you explanations on why you do things and hope to hear the flying results as well as the finish. H^^
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on August 15, 2021, 06:43:32 PM
Fillets on the stab, too.  At least from a scale perspective, these are a bit more hidden.  Again, stunt guy building a scale plane; I wanted the paint to stick at the joint.  I could see going over the top on this with a really detailed scale plane and bolting the stab onto the fuse.  Even for a profile, if you could figure out how to do it (and you were going over the top).

Nuh uh -- ain't going to do it.  It's just a pretty Ercoupe model, lacking some of the trimming.

The three pieces under the filletted stab are cover panels for various holes (radio hatch, weight box, tail weight box) that I'd been sorta thinking "oh yes, I need to do those).  I unearthed them today with a "my gosh, those aren't nearly as done as I thought they were!".

So -- lots of dope and sanding for those.  If I feel comfortable about painting over nitro slobber, those may go to their first contest with a coat of clear over the sealer.

Oh -- and a brag shot that I sent to my cousin, since he sent me a picture of Guitar #6 in the final stages of getting put together.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on August 17, 2021, 12:25:22 PM
I got the canopy halfway masked, and then remembered that I'm planning on painting a black band on the outside to help hide the black glue that's goobered up on the inside.

I also realized how I want to do this next time, so that the glue application can be a bit uncontrolled but will still not make as much of a mess as I have.

Basically, I'll make a groove around the inside of the canopy mount to contain extra glue.  If this is coupled with glue that matches the color of the cockpit inside (and I'm going for flat black again because it hides so many sins) then -- hopefully -- the glue will be well hidden even if it's not absolutely perfectly regular.

What I really need is a way to send a pilot inside that cockpit -- then I could mask off the inside, and have the pilot peel off the tape!
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on August 24, 2021, 09:10:16 PM
I got the canopy all masked off, and went to paint it white.  And screwed up.

I'm using a bit of white in my sanding sealer as a marking coat (seems to be working so far, cross my fingers).  It turns out that sanding sealer with a bit of white in it looks just like white dope!  It just doesn't cover very well at all...

Fortunately, actual white dope covers pretty well, and now my canopy is sprayed.

I marked the jar, so I won't forget...
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on December 30, 2021, 06:56:05 PM
And, after a good long break for work and rebuilding mowers and whatnot, I've gotten some stuff done.  Tail hinged (oooh, lots of progress there).

This is getting a "stunt hinge" -- one long wire, with a stub coming out on one side of the rudder, and a big ugly gap that I'm not going to bother to fill.  I'm in git-er-done mode.  I may seal the gap with white Monocoat or if I can find a white "Scotch" tape I'll use that.

The scariest part for me is that the elevator only has about 15 degrees of "down".  If you build an Ercoupe, and it looks scale, then it's going to have restricted elevator movement, because -- Ercoupe.  Good thing I won't be trying any outside maneuvers, though.
Title: Re: Ercoupe Build (slow)
Post by: Mark wood on December 30, 2021, 09:39:11 PM
Ercoupes are cool old airplanes. I have a couple friends that have and fly them. One guy at our airport has a very nice he flies quite a bit. I haven't spoken to him about it much though. One of the other DME guys flies his in to the school occasionally when he's giving an A&P test. His is also very nice and he restored it several years ago.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on December 31, 2021, 10:11:59 AM
Ercoupes are cool old airplanes. I have a couple friends that have and fly them. One guy at our airport has a very nice he flies quite a bit. I haven't spoken to him about it much though. One of the other DME guys flies his in to the school occasionally when he's giving an A&P test. His is also very nice and he restored it several years ago.

It's one of the few airplanes that I've built more than one scale model of -- this will be three, if you count the Bostonian.

While I've been building this, oh so slowly, Chris Cox has gotten his full-sized one in the air.  I haven't seen it in person, but it does look good in pictures.
Title: Re: Ercoupe Build (slow)
Post by: Avaiojet on December 31, 2021, 01:29:28 PM
No rudder pedals.

A beautiful aircraft for it's time and a great aircraft to model.

Charles
Title: Re: Ercoupe Build (slow)
Post by: Mark wood on December 31, 2021, 01:36:39 PM
No rudder pedals.

A beautiful aircraft for it's time and a great aircraft to model.

Charles

A significant portion of the fleet have been modified to have rudder pedals. This is one airplane I have zero time in but have always had interest in flying both the original and modified versions.
Title: Re: Ercoupe Build (slow)
Post by: kevin king on January 07, 2022, 12:12:32 PM
And ain't I making fast progress?  I'll be lucky to have something flyable -- I think I have too many irons in the fire.

Tim, I find fast builds and fast paint jobs go against my "Do it right the first time" thinking. Seems like the time you save now will just be paid correcting things later.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on January 08, 2022, 04:49:31 PM
A significant portion of the fleet have been modified to have rudder pedals. This is one airplane I have zero time in but have always had interest in flying both the original and modified versions.

This one has no rudder pedals, so in that regard it's like the factory prototype.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on January 08, 2022, 04:52:58 PM
It's the weekend, it's sunny, and I really need to lay some paint on this.  I've just about used up today's sunlight, but I'm getting the little bits & bobs ready for paint.

On reflection, I decided that to paint the two hatches, I'd CA washers on the backs, then hold them to a piece of scrap iron with magnets -- which I'm doing here.  Time will tell if it works out, or if I just blow the things off the magnets and onto the dusty floor.  It feels firm enough to stand up to spray paint, though.

Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on January 22, 2022, 07:07:53 PM
All silver!  Or -- mostly all silver.  I decided it's better to have to go back for a second coat tomorrow than make runs or sags today.

And it's true what they say about painting your plane silver revealing all sorts of unexpected flaws -- for instance, I didn't realize just how long it's been since I've cleaned the cobwebs off that window until I looked at this picture!  (And the plane has some nasty divots -- I'm pretending really hard that I didn't see them, because I'm trying to be in pure FIFI mode here).

Need to find out what happens if I try to color sand a silver base coat.
Title: Re: Ercoupe Build (slow)
Post by: Mark wood on January 22, 2022, 07:33:47 PM
All silver!  Or -- mostly all silver.  I decided it's better to have to go back for a second coat tomorrow than make runs or sags today.

And it's true what they say about painting your plane silver revealing all sorts of unexpected flaws -- for instance, I didn't realize just how long it's been since I've cleaned the cobwebs off that window until I looked at this picture!  (And the plane has some nasty divots -- I'm pretending really hard that I didn't see them, because I'm trying to be in pure FIFI mode here).

Need to find out what happens if I try to color sand a silver base coat.

What are you using for silver Tim? Just sand and go forward. Real silver Ercoupes are done in just plane silver dope which has aluminum powder in it. It isn't super shade perfect by any level in real world airplanes. Don't fret the small stuff. Just make it go. It'll be badass cool...
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on January 22, 2022, 08:44:08 PM
What are you using for silver Tim? Just sand and go forward. Real silver Ercoupes are done in just plane silver dope which has aluminum powder in it. It isn't super shade perfect by any level in real world airplanes. Don't fret the small stuff. Just make it go. It'll be badass cool...

It's Sig silver, and it's just there as a blocking coat -- white is next, and hopefully it won't be sparkly.
Title: Re: Ercoupe Build (slow)
Post by: Mark wood on January 23, 2022, 06:07:44 AM
It's Sig silver, and it's just there as a blocking coat -- white is next, and hopefully it won't be sparkly.

It won't be sparkly. In that case I totally wouldn't worry about it. Of course, I wouldn't worry about it regardless.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on January 23, 2022, 03:47:31 PM
@#$%.  Just @#$%.

The picture doesn't do it justice.  It's truly horrible.  There's some sandpaper in that fin's future, for sure.

Oh well -- it's the only sag on the plane, and it's all one color now.
Title: Re: Ercoupe Build (slow)
Post by: Mark wood on January 23, 2022, 04:36:33 PM
@#$%.  Just @#$%.

The picture doesn't do it justice.  It's truly horrible.  There's some sandpaper in that fin's future, for sure.

Oh well -- it's the only sag on the plane, and it's all one color now.

Worse things could happen.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on January 23, 2022, 04:45:26 PM
Worse things could happen.

True.  I almost dropped it onto the dirty floor a couple of times, while it was still wet.  I think I need to get fancier with my plane-holding system (it currently features saw-horses, vice-grips, and a lot of juggling when you change positions).
Title: Re: Ercoupe Build (slow)
Post by: Mark wood on January 23, 2022, 04:47:25 PM
True.  I almost dropped it onto the dirty floor a couple of times, while it was still wet.  I think I need to get fancier with my plane-holding system (it currently features saw-horses, vice-grips, and a lot of juggling when you change positions).

I just recently upgrade my game on that for exactly the same reason. I made a mount that fits on the end of a microphone stand I have laying around. It was worth the hour or so it took me.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on January 23, 2022, 06:55:31 PM
I just recently upgrade my game on that for exactly the same reason. I made a mount that fits on the end of a microphone stand I have laying around. It was worth the hour or so it took me.

I'm thinking of making a mount I can clamp onto the end of a sawhorse, that'll let me tilt & whirl the plane, then clamp it down solid.

Or just screw it onto the sawhorse, since 50% of the use those sawhorses get is as painting tables.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on February 12, 2022, 03:20:10 PM
Well, it's all white now, with two coats seeming to be enough.

I did manage one run in the white -- fortunately it's on the bottom of the plane, so depending on how bad it is I may not even bother to try sanding it out.  I did try to take a picture of the run, but trying to photograph a run in white paint is not an easy thing.

I thought I'd show my backwoods painting fixture.  1/2" square aluminum, surplus from a job long ago, with a plate bolted onto it that goes into the motor mount holes -- all typical there.

The special "I live in the sticks" part is the vice grips.  The one on the aluminum square is so I can handle the plane one-handed, without touching the paint.  The one on the sawhorse actually holds things in place while I'm painting.

I can rotate the plane on it's long axis any amount I want, as long as it's increments of 90 degrees.

So far I haven't dropped a wet plane into the dirt, so, fingers crossed.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on February 12, 2022, 03:26:04 PM
Obligatory picture of a white plane.  It never ceases to amaze me how much the covering loosens then tightens up again when you spray it.
Title: Re: Ercoupe Build (slow)
Post by: gene poremba on February 23, 2022, 07:38:25 AM

 Tim, i enjoy looking at your progress on the aircoup. I dont comment much because unless i have something to contribute i just read and learn. That said, i look for ward to your build pictures and progress......Gene
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on February 23, 2022, 07:57:21 AM
Tim, i enjoy looking at your progress on the aircoup. I dont comment much because unless i have something to contribute i just read and learn. That said, i look for ward to your build pictures and progress......Gene

Thank you Gene.

At the moment my work-life balance is heavily weighted in favor of "work".  The only physical thing I've done with it is to go over it very lightly with 2000 grit paper, to take off the high spots that feel like bits of dust that stuck to the paint.

This isn't as bad as it could be, because the stage I'm at with the plane is looking over the pictures of the original and contemplating masking and spraying the red.  I need to get past "OMG I need to do that?!?!", through "OMG, I do need to do that :o" and finally to "OK, I'm going to do that."

When I get a chance to touch it again, I'll be sacrificing frisket, newsprint, and tape to the Masking Gods, and hoping I get it mostly right.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on March 06, 2022, 05:40:36 PM
So I had planned on squirting red on it today (good painting weather), but I had utterly failed to schedule for the day or two of getting it masked -- bad me.

I took the side view photo and scaled it to match the model; I'll use that for the numbers and the swoosh on the fins.  I'll probably take a first cut (as it were) with frisket; if that doesn't work I'll make up a cut file and see if I can hit someone up for some masks.

Here's my size check of the photos.  Because the side view had some distortion I had to play some photoshop games to get the fin sort of right, and it's still not right-right.  But it's close enough for a pattern for the swoosh -- or at least I'm declaring it so.

Looking at the width of the pinstripe between the red bottom and white top of the plane, I'm thinking I want to ink that -- except that it needs to color match the paint.  So I either need to just use a red Sharpie and accept that the shade won't match, or I need to figure out how to make an "inked" line with dope (lots of retarder and a good old dip pen or drafting pin?)
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on April 26, 2022, 05:22:33 PM
So I had planned on squirting red on it today (good painting weather), but I had utterly failed to schedule for the day or two of getting it masked -- bad me.

"Day or two".  Oh, yes.  Of course.

I'm not sure what happened between March 6th and the end of the month, but on the 30th I crashed my main stunt ride, and have been resurrecting it full time.  I missed the Jim Walker Memorial this past weekend (and I ended up judging every Stunt event, anyway).  Just got that done enough to hang up, look out side, say "rain, @#$%" and turn to other things.

Getting ready to cut out lettering.  Here's the template -- this will help me get matching radii on all the corners, in hopes that it won't look too too bad.

If it works nice, when it comes time to outline things in black I'll under cut it, and use it as the guide for the pen.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on April 28, 2022, 10:14:07 PM
OK, that was a dead end.  I realized that what with working with a picture that was taken at an angle of a curved fuselage, parallax lens distortion blah blah blah, taking it from a picture was not going to work.

Back to the drawing board -- or drafting program.  Did a bit of magic in Gimp (basically open-source Photoshop) to get it part way to being straight and square, then imported it to LibreCad (open source 2D CAD program).  Then drew the idealized letter outlines over the picture.

Am now cutting out the masks.  Freehand on the curves, straightedge on the straights.  I just spent an hour, I'm about 1/4 of the way through.  Should get it done over the weekend.

This would have gone faster if I'd contracted with someone to make masks -- but I'm not feeling like I have calendar time, so I'm going to spend some me-time and get this done.  It'll look fine.  From ten feet away...

Maybe I'll make the Regionals.  Maybe...
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on April 30, 2022, 04:46:51 PM
Port letters applied.  They're not going to be perfect, but I'll be happy with a "looks good from 10 feet away" sort of finish.

The top shot shows the letters still on the frisket paper backing.  I cut strips of frisket to hold the letters in place, and added masking tape "handles" to the ends.  I used those to transfer the letters to the plane.

The horizontal tape is my guideline; it's my best guess at matching the position on the plane of their letters. 

Note in the picture my cell phone, with the prototype picture on it -- the scale documentation came from Airborne Media, which basically sells you a zip file with a web site on it.  Because I'm a tech-head, I set up my shop computer as a local web server; more sensible people can probably figure out how to load this stuff onto their phone or a tablet.  At any rate, it's kind of the modern equivalent to having the scale documentation right there while you're building.

On to the other side...
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on April 30, 2022, 07:11:18 PM
Well, that went quicker than I thought.

Sometimes the second time I do something it turns into an ugly snarly mess.  Sometimes it's better.

Thankfully, this time it was better.
Title: Re: Ercoupe Build (slow)
Post by: fred cesquim on May 02, 2022, 03:58:32 AM
Well, that went quicker than I thought.

Sometimes the second time I do something it turns into an ugly snarly mess.  Sometimes it's better.

Thankfully, this time it was better.

looks good, hope to see it flying soon!
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on May 03, 2022, 10:27:58 PM
So, this is taking a bit longer than the two hours or so that I predicted (d'oh).

I'm kinda guessing on where the paint lines go -- and learning about just how many pictures I want for the next scale subject.  If you hear about a ruckus and an arrest for obstreperous trespassing at a fly-in somewhere in Oregon, that'll be me crawling around, under, and over someone's plane, taking pictures.

Bottom wing masked.  Frisket semicircles for the curvy parts (which probably are't visible, but the big fat blue tape lines do not just meet in a mess like that).  Tan vinyl curvy masking tape defining the straight parts, and blue to hold down the tan, because I've learned that it doesn't always want to stay down.

I maybe might get it painted this weekend -- I hope so, 'cuz time's a wastin'!
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on May 05, 2022, 08:47:55 PM
Ready for some clear to seal the tape edges, and then some red.

Still maybe-might on painting this weekend: it's going to be rain, rain, some rain, and then perhaps more rain.  Since my "paint booth" is the covered porch off the end of my shop, it needs to at least not be raining before I can paint.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on May 10, 2022, 04:36:29 PM
Someone has vandalized my aeroplane!  They've gone and painted it all red!

Even though it's a workday, this is the only sunny day predicted for a good long while, and I need to be at a show with that thing in 17 days.  So (thank goodness for remote work!) I snuck in a break and squirted some paint.

No runs -- that's a personal victory for me.  I think there's one sag in the entire paint job, and that's a mild one in the silver undercoat.  There's a couple of patches that are a bit thin -- I'm going to inspect them and decide what to do, but I'm leaning heavily toward just letting sleeping paint lie and squirting clear on this whole thing.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on May 11, 2022, 10:26:56 PM
After some waffling about the fact that my one heavy coat of red is light in places I decided to heck with it -- I'm going to strip off the masking.

I still need to do the swoosh on both fins, and the numbers on the other side.  But -- this thing may end up looking like a plane!

I still need to do the accent stripe along the white/red interface, and I'm pretty sure that the numbers are outlined in black -- but things are definitely coming together.
Title: Re: Ercoupe Build (slow)
Post by: fred cesquim on May 12, 2022, 10:56:02 AM
After some waffling about the fact that my one heavy coat of red is light in places I decided to heck with it -- I'm going to strip off the masking.

I still need to do the swoosh on both fins, and the numbers on the other side.  But -- this thing may end up looking like a plane!

I still need to do the accent stripe along the white/red interface, and I'm pretty sure that the numbers are outlined in black -- but things are definitely coming together.
GREAT looking bird!! sweet
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on May 12, 2022, 12:50:30 PM
GREAT looking bird!! sweet

As long as I don't let anyone get within six feet of it, they'll think it's perfect.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on May 12, 2022, 08:05:23 PM
Gear straps/covers.  Made from aluminum that I had lying around, somewhere around 16 to 18 gauge (right around 1/16", at least).

They'll get painted red -- along with that radio hatch cover that's standing out like a sore thumb (or maybe zombified -- sore kinda implies red, and that's exactly what it isn't).

I really ought to do nice Ercoupe-ish pants, but I'm just not going to go that far this time around.
Title: Re: Ercoupe Build (slow)
Post by: Chris McMillin on May 13, 2022, 03:25:43 PM
Looking good!
Oh, do Ercoupe-ish pants, especially if they are on the photos of the airplane you're modeling. They look great and this model is worth it.
Chris...
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on May 13, 2022, 06:13:39 PM
Looking good!
Oh, do Ercoupe-ish pants, especially if they are on the photos of the airplane you're modeling. They look great and this model is worth it.
Chris...

Well, the one CL scale contest in my area for the year is in exactly two weeks, so it's going to have wires sticking out of the wing for that first contest.  The original has covers over the legs, but it doesn't have those nifty Ercoupe spats -- I may have done that on purpose, to hold down on the detail work.

Somewhere toward the beginning of this thread there's a picture of the front landing gear I made, with a Real Live Yoke brazed onto the music wire.  It'll look a lot better painted, which will also happen after this year's contest.  You'll find out here if it doesn't survive it's first landing.

(https://stunthanger.com/smf/scale-models/ercoupe-build-(slow)/?action=dlattach;attach=288499;image)
(https://stunthanger.com/smf/scale-models/ercoupe-build-(slow)/?action=dlattach;attach=290613;image)
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on May 13, 2022, 06:56:42 PM
Looking good! ... and this model is worth it.

It's benefiting a lot from photography.  There's lots of little details that are proving a learning experience for me.  It's going to be a five- or six-foot finish.  If it were a stunter then even with a full fuselage it'd probably only be good for 16 or 17 points from a real stickler of a judge.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on May 15, 2022, 09:56:15 PM
More things that benefit from photography.  Control surfaces drawn on, and I've made a start on the trim lines.  I was going to try to use matching dope, then decided to just use a red sharpie -- which seems pretty close.  I'm declaring it close enough!
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on May 17, 2022, 03:20:56 PM
Perfection is not being achieved.  But the contest is in ten days, and somewhere in there I need time for dope to dry and test flights to be performed.

I hand-drew the tight curve toward the back of the swoop-te-do; I don't really like it, but perfection is the enemy of good enough.  I'll cover it in clear, make it to the contest, and it'll mock me until the end of my days...

To do better on the longer part of the swoop, I made a rule out of old, heavy, mouse-chewed balsa.  It seems to have worked well -- and by luck, the curves match on the other side, so I can reuse the same ruler.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on May 17, 2022, 05:14:56 PM
The tools are getting lower and lower tech here.

Center line is with an old metal drafting pin, the window edges are just with a brush.

On the prototype this is a pair of windows with black edging -- I'll do that with a felt pen, tomorrow, then the whole thing will be ready for clear.  Hopefully.  Maybe.  I tend to think I'm done, then find one last little thing.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on June 16, 2022, 10:34:38 PM
Well, it's been hung up under a sheet in my airplane room, because I ran out of clear.  That pint of Sig Litecoat that I was sure I had turned out to be a pint of Supercoat, and the finish is taut enough, thank you very much.

A quart of Certified clear just arrived from Aircraft Spruce -- I'm going to find out whether mixing & matching Sig and Certified is clever or stupid.

I seem to remember someone saying that Sig gets its dope from Certified.  Got my fingers crossed, because the Great Supply Chain Crisis of the 20's has hit Sig's dope supply, and I don't know when I'll be getting any really-o truly-o Sig dope.  It's on back-order, but it's not here.

So, results will be somewhere between perfectly OK, and my first official flight being accompanied by a soft "fwoop" as all the clear dope splits off the airframe and does an imitation of Wonder Woman's Invisible Airplane, spinning in the breeze as it slowly settles to the tarmac.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on February 19, 2023, 05:49:24 PM
Well, I got busy with work, and...

I did get a quart of Certified clear, it's been working well.  Back in July I put on a coat.  On the advice of one of the best finishers in my club I backed off on the retarder and put on a light coat -- I ended up with orange peel and blush.  I probably went too far with that suggestion, but Dave, I'll keep it in mind when I'm overdoing the retarder!

Just yesterday I got on another coat, and man, I'm relieved that even after six months of drying, a coat that doesn't blush will un-blush the coat underneath it.  I may have overdone the retarder but I don't care.

Posting the July paint for compare/contrast.  The shot was taken right after I painted it, so it looks a bit worse -- shooting paint on the canopy always makes it fog up inside, even if the outside paint isn't fogging.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on March 11, 2023, 01:20:07 PM
Two boo-boos. 

The first is just plain old sand through the color -- oops.  Clearly I didn't have as much clear there as I thought.  That'll get spotted in, and there'll be, well, a spot because I didn't do a good job with the original color coat.  Next time...

The second one is more interesting.  The fins are made of 1/4" balsa, with a rectangular cut-out for the stab to go into.  This means, inevitably, that there's a huge discontinuity in the wood right there -- which is going to show no matter what I do.  Even if I had gone through more iterations of clear coat and sanding (or did so now), it'd be smooth at the temperature I sanded it at, but show a ripple at other temperatures (like, in the sun at a contest).  So, next time I do this I'll laminate the part -- for something like this I'll use 3/16" and 1/16" wood, and just make the cutouts in the 3/16" part.  There will still be a discontinuity, but hopefully it won't show.

Being me, this probably means I'll make two left fins, but that's my own personal cross to bear.
Title: Re: Ercoupe Build (slow)
Post by: Gary Dowler on March 23, 2023, 10:40:56 PM
Two boo-boos. 

The first is just plain old sand through the color -- oops.  Clearly I didn't have as much clear there as I thought.  That'll get spotted in, and there'll be, well, a spot because I didn't do a good job with the original color coat.  Next time...

The second one is more interesting.  The fins are made of 1/4" balsa, with a rectangular cut-out for the stab to go into.  This means, inevitably, that there's a huge discontinuity in the wood right there -- which is going to show no matter what I do.  Even if I had gone through more iterations of clear coat and sanding (or did so now), it'd be smooth at the temperature I sanded it at, but show a ripple at other temperatures (like, in the sun at a contest).  So, next time I do this I'll laminate the part -- for something like this I'll use 3/16" and 1/16" wood, and just make the cutouts in the 3/16" part.  There will still be a discontinuity, but hopefully it won't show.

Being me, this probably means I'll make two left fins, but that's my own personal cross to bear.

I know a fix for this.  Take a fine tip brush, get some clear and just dab it into this line around the end of the stab.  All you're doing is filling this little line, not more.  Wait for that to set up some, then repeat this 3-4 times until you have it built up above the surrounding clear surface.  After it dries, wrap some 1500 grit sandpaper around a flat stick and with some water, wet sand it smooth. After that you can polish the area and it should be virtually invisible.
Gary
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on April 29, 2023, 12:13:37 PM
I realized that I haven't actually polished a dope finish before ( :o).  So I did a couple of test patches to find out that sanding with 2000 grit then rubbing it with ancient Turtle Wax rubbing compound makes things -- shiny!

So I now have the left top wing sanded, and I'm proceeding on to the rest of the plane.  Hopefully I'm not dooming my chance to make it to Roseburg this year just by saying -- maybe I'll make it to Roseburg this year!

I'm actually not sure how to proceed once I have the shiny plane in hand -- the final paint was last week; with luck it'll be assembled and ready to fly next week, just in time for the Fireballs club meeting.  What I don't know is when it's advisable to wax the thing, or spray it with fuel-proof topcoat.  I've been advised to wait 90 days before waxing -- but what to do in the mean time?  Just fly the thing?  Then degrease the @#$% out of it before topcoat after it's outgassed for a few months?
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on April 29, 2023, 01:44:00 PM
Oh @#$% I need to do documentation.  I'll just visualize points flying out the window while I'm doing it, to stay calm.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on April 30, 2023, 04:00:30 PM
Getting shiny!

I think I mentioned some time back that this project started because I'd injured my shoulder and didn't think I was going to fly stunt ever again.  Then when my shoulder got better I decided that I'd use this as a practice piece for a really-o stunt finish.

Which -- is coming out OK.  There's lots of mistakes that I've left in because of laziness (and some deviations from scale for the same reason), but at least it'll be shiny!
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on May 06, 2023, 07:57:46 PM
A good long time ago I had this all mocked up for an old Fox 40.  The longer I dinked with the engine and the more I thought about it, the less I liked it.  Mostly, I have two very old, used, engines that have obviously been through the wars.  One would barely pop, and the other wouldn't stay running on the stand.  So, today I got it changed over to run a Tower 40 -- which also means it'll run an OS 40/46/LA/FP, if the Tower 40 doesn't work out.  So I have options.

Fortunately for me, I've started building my planes with engine mounting adapters, so this was just a matter of making new adapters instead of hacking into that nice pretty nose to move the bolt holes.

Just for chuckles, I'm including a shot of the Tower 40 that I'm not going to use, for some reason.

(https://stunthanger.com/smf/scale-models/ercoupe-build-(slow)/?action=dlattach;attach=291851;image)
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on May 07, 2023, 04:11:20 PM
On its feet!

Still work to do, probably the least of which is to tweak the main gear so it's not splayed out.  That should have been expected, given the dihedral.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on May 15, 2023, 02:16:44 PM
In the process of putting the radio in, I left dents in the silkspan next to the radio hatch.

(A) next time, there will be sheeting all the way around the hatch
(B) sigh.  This is why I can't have nice things...
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on May 15, 2023, 02:20:54 PM
The radio compartment is in the wing, and as such the height is controlled by the wing thickness.  What I had wouldn't fit, because the connectors come straight up off the radio.

So -- modify the radio.  It all fits now, at the cost of some time on the electronics bench.  A better approach may have been to find a radio receiver that already has the connectors coming off an end or edge, but hindsight, 20-20, yadda yadda.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on May 21, 2023, 02:07:18 PM
Almost done -- and almost out of time.  Hopefully I can get it all put together and the engine running in the driveway today, because the NW Regionals are next weekend and I don't want to show up without having done any test flights!

I got set back a week by getting sick, then I was slow to start up -- eventually I realized it's because I need to start sticking on ugly things, like control horns and a fuel tank.  I'm over that now (and the plane is a bit uglier).

Pictures show a control horn that I was given at a factory tour of Sig back in the mid 1970's; my brother and I were traveling through on business and he graciously took a detour to Montezuma (which is as close to the middle of nowhere as you can get in Iowa).  It's finally getting used (and is making the plane uglier).

Also shown is the control rod marked out for cutting, and then getting glued in. -- I almost pulled a classical Tim move; I had put the thing into the ball link on the bellcrank just one or two turns -- that's the first mark.  The second mark is because I realized what I'd done and cranked in another 9 turns -- had I remembered afterward I'd have a short control rod, had I not remembered, there would have been one memorable flight early on.

Not shown: hinges are glued up and the fuel tank is prepped.  I'll be attaching it to the fuselage inboard of the motor.
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on May 21, 2023, 05:01:12 PM
In theory I just need glow plug, prop and lines, and I'm ready to go.

Oh -- time for a test flight.  That's a necessity  :o .
Title: Re: Ercoupe Build (slow)
Post by: john e. holliday on May 21, 2023, 05:06:20 PM
After all this time and effort, hope it flies well for you. D>K
Title: Re: Ercoupe Build (slow)
Post by: Tim Wescott on May 21, 2023, 05:48:08 PM
After all this time and effort, hope it flies well for you. D>K

Me too!