My ride for the Regionals in May, if I can get it done.  I just got the plans from the printer -- they lack detail.

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.

Just curious, what will the wingspan be?

1/8 scale, 60".  I'm trying for not to big, not too small.

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.

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.

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.

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.

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.

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.

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

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.

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.

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.

 How's the 'Coupe coming?

 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. 

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.

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.

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.

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.

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.

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.

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.

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.

Another oops?  Wait til you start sanding fuse on built up fuse to discover you left out the tail wheel gear.

Ercoupe tail wheel? All the ones I worked on had nose wheels.