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Building Tips and technical articles. => Building techniques => Topic started by: Douglas Ames on October 05, 2011, 06:25:13 PM
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I started with the crutch filler block custom cut for the width of a Saito .40 and realized the limited space left for a plastic clunk tank. I eliminated the bottom 1/8" side pcs. and used 1/2" tri stock instead to tie in the 1/4" top on the crutch, also used a couple pcs. of 1/2"x3/8" beam stock for braces and did away with the crutch filler aft of the 2nd bulkhead. The reason was to open up the fuel tank compt. to the max. I will be using a Sullivan 4 oz. round tank. More on that later.
I had to push the engine all the way up to the nose ring due to the ring thickness, I also wanted to get the prop away from the large cowl for better efficiency. The nose ring is 2 pcs. in the kit but came up a little short in dimension compared to the ply N/R doubler so I shimmed it 1/8". Lots of carving, sanding and contouring!!! You'll be removing over 50% of it so don't fret on weight...yet. I split the fuse up in quarters and contoured each quarter individually, that way I kept things symmetrical. Don't forget to block your corners or you'll see daylight.
The fuse sides were pre-assembled with ply doubler, stringers and 1/4" external doubler, then book-matched & checked for dimensions. This sets the accuracy of your fuse. I didn't use a jig, just a square and glass surface. I had to use a large clamp and some moisture to get the fuse glued together along with a precisely cut tail block behind the last former to straighten everything out before the aft fuse stringer s went in. I reccomend this - "triangulation", it's worth the minimal weight, if any. I moved the cockpit aft 1" for asthetics and give it a sleeker look. A custom canopy will be needed.
I decided to build the Bud Light "Super Corsair" of the 80's. A R-4360 powered Beast built from a ex-movie prop, an A-26 cowling and P-51 spinner. 8 feet was chopped from the wings but I have no intention to duplicate that! I'll just square up the tips for that look. Maybe a 3" span change? Spinner is a Hanger 9, aluminum 2 1/2", very nice quality!
Next up is a tank mount and plumbing, tail wheel and stab install.
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More pics...
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AWESOME JOB DOUGLAS!! y1
Keep the pics coming & "Tight Lines!" H^^
Wes
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Here's the alignment block...Keeps your fuse from looking like a Banana. ;D
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Impressive CLP**
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Lookin' great so far Doug! I still have my doubts about the .40 choice though, but I guess we'll see.
Check this site and scroll down to the "Cat's and Corsair's" five view line drawing section:
http://www.taichiunlimiteddrawings.com/#Bearcats and Corsairs
You will find some excellent reference for markings for your Bud Light version. Great reference for your models outlines and proportions too. These drawings are all very accurate, unlike a lot of stuff out there. There is info here on pretty much any Warbird air racer you can think of, past or present.
Thanks and please keep the pics coming. y1
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Lookin' great so far Doug! I still have my doubts about the .40 choice though, but I guess we'll see.
The Corsair is 561 sq/in, I fly a 576 sq/in profile with a Saito 40 and it has plenty of power. The Brodak P-40 is 560 and we all know it does great with a Saito 40. The only unknown is the final weight of the Corsair, if he can keep it somewhat under 50 ounces he will be fine, 45 would be wonderful.
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If you made it E power you could reenact the real Super Corsair's harrowing final flight at the Phoenix Air Race S?P VD~
Sorry, I know that was naughty mw~
The corsair is one of my favorite planes, I'm going to enjoy watching this thread. Its awesome that Brodak kitted this version!
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I always loved the Bud Light Corsair. I have had a picture of it on my shop wall forever. I'll watch this build with interest.
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You will find some excellent reference for markings for your Bud Light version. Great reference for your models outlines and proportions too. These drawings are all very accurate, unlike a lot of stuff out there. There is info here on pretty much any Warbird air racer you can think of, past or present.
Thanks and please keep the pics coming. y1
Thanks for the ref's. That's exactly what I need.
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The only unknown is the final weight of the Corsair, if he can keep it somewhat under 50 ounces he will be fine, 45 would be wonderful.
Exactly what I'm thinking Bob, it's going to have to be built very light for it's size. Plus the design will have more drag than a comparable profile. I know and respect your experience with these designs, but I would be going for more power on the Corsair. Don't get me wrong, I love the Saito .40, but I don't expect much, if any, reserve power in this application. Just me maybe, I haven't seen the design in the flesh to get a total "feel" for it. Maybe it doesn't present as big as I'm imagining. I just always figure it's a lot easier to back off the power a little bit than to find more that just isn't there in the first place. It will be fun to see this one done. y1
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Here's how I'm doing my Stab and Elevators. I put the hinge point (Du-Bro) in the center of the leading edge of the elevator with about a 1/32" gap. I also tapered the stab. spar and LE of the elev. from .375" to approx. .280", this keeps the surface angle constant otherwise it would wash out along it's span due to the taper in the elevator profile (different chord widths). I will also mount the stab with 1*+ incidence for good measure. Nothing spectacular but technically correct I think.
Need to continue sanding and blocking in the tail this week. It all fits good & straight so far.
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Doug that is outstanding keep up the good work.That engine will work very well did Bob do his magic already.
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Here's how I'm doing my Stab and Elevators. I put the hinge point (Du-Bro) in the center of the leading edge of the elevator with about a 1/32" gap. I also tapered the stab. spar and LE of the elev. from .375" to approx. .280", this keeps the surface angle constant otherwise it would wash out along it's span due to the taper in the elevator profile (different chord widths). I will also mount the stab with 1*+ incidence for good measure. Nothing spectacular but technically correct I think.
Need to continue sanding and blocking in the tail this week. It all fits good & straight so far.
Very nice. Man I love watching this stuff. y1
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Looking great Doug. Makes me want to get started building mine all the more. Keep posting pics please.
Rick Henry
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Here's my vertical fin ready to install.
I trimmed 1/4" from the bottom fwd and aft edges, tapering up to -0- at the top then added 1/4" on the upper trailing edge, tapering down to -0-. This gives it a little more scale profile I think.
I glued everything as one and left the outboard surface flat. The inboard surface is aero-shaped with a 1/8" trailing edge. Pat J. suggested 3/8" offset so I sprayed the fin with glass cleaner (w/ ammonia) and curled it with some jury-rigging. I think this is a more efficient way of producing the required yaw than a cocked rudder (less drag maybe)...it also looks better ::)
ps - A super trick to steam out dents is some glass cleaner (blue stuff) and your monocote iron. Evaporates quick.
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You understand that by doing the rudder this way people are going to constantly say "Hey did you know your rudder is warped?" ;D
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Yeah, I expect that, LOL. ???
I'll be mounting it tonight 1/8" left of center to fit it on the narrow tail block. It will effectively have 3/8" offset overall with a nice fillet.
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Doug,
I have the orginal profile Corsair that Pat Jonston built for the Brodak kit. It has a Satio .40 in it and flies great. You won't have a problem with power for sure. Motor has one of Pat's carb mods on it, so there is just a NVA and a nylon screw to adjust air flow. Works great. Gerald Schamp
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Gerald- That's good to know. Thanks! I'm trying hard not to build a balsa brick.
Currently finishing up the tail and tail gear. Roughed out the cockpit canopy (modified SIG teardrop) and have some idea where to go with that.
How was the wing build? Looks pretty straight forward.
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>>Looks pretty straight forward.<<
Well straight forward, but not straight.
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I've got the tail roughed out, the verticle fin installed and added the req'd. small dorsal fin. Ready for fillets and final sanding/ covering.
Cockpit is nothing extrordinary, I had to add a 1/4" shim under the 1/8 pilot to get the right height and added a pc. of 1/16" for a seat back. Couldn't find a phone book that small for him. Canopy will be a trimmed down SIG 10" teardrop. I'll be using Al Rabe's methods for cockpit detail and canopy install (strips of glass/ resin).
Tail gear is DuBro's .40-.60 tailwheel. Simply modded by installing a brass sleeve/ epoxy instead of the steering arm. Perfect fit! It's dimensionaly the same as the plans and only weighs 11 gr.
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Really nice work, the sheeting looks like it could be challanging. Like the tailwheel also. CLP**
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Looking great Doug, please make sure to post some "how to" detail pics on the canopy install.
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Hey Doug, How is the Corsair coming along? Got any new pics?
Rick Henry
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Doug,
You're doing a great job! Kudos!!
Corsair, my favorite warbird.
Couple of quick questions.
The cowling nose block, was that laser cut and how thick is it?
Elevator control horn, came with the kit? What's the distance between the bends?
Hope you don't mind.
Thanks,
Charles
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I'm embarrassed to say progress is slow due to the holidays, OT at work and a scooter accident Christmas eve. (Indian Vespa clone - totaled). I'm starting the wing and getting ready to detail the cockpit.
Avio- the nose block is saw cut balsa, glued behind the nose ring (2 pc. laser cut) on the top. The external fuse doublers are 1/4". It all comes together when you start carving off chunks of balsa, then shaping and sanding a uniform profile. I did mine in quarters with a midwest plane and drum sander. You can put any powerplant you want in this kit - lots of room.
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Doug,
Thanks for that info.
I also asked about the narrow elevator control horn. Looks like it was made just for the Corsair? That came with the kit?
You're a ways away from paint and finish, but I have all the Budweiser graphics, also available in paint masks.
A-Jet
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Cockpit is nothing extrordinary, I had to add a 1/4" shim under the 1/8 pilot to get the right height and added a pc. of 1/16" for a seat back. Couldn't find a phone book that small for him. Canopy will be a trimmed down SIG 10" teardrop. I'll be using Al Rabe's methods for cockpit detail and canopy install (strips of glass/ resin).
I bought an Acrylic paint set at Hobby Lobby and a brush asst. and went to town last week getting the cockpit finished. I think the little guy turned out good. Not a scale job, acceptable for stand-off scale. The helmet was the bomb in the early 70's - Easy Rider 8) Need to attach the canopy.
Think I need a landing for the fwd. edge of the canopy or just a bead of epoxy and then glass in the seam?
The rest of the edges overlap by about an 1/8".
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Thanks for the update and the pics here Doug, things are looking great. I'm really interested to see how you pull of this canopy install.
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The pilot looks great. If you browse thru SSW's on the Rabe build, you will find he lays a strip of fiber glass alog the joints of the canopy. I also think Sparky has on his builds how he does his. Of course it has been a while since Sparky has posted a build. D>K
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What's the latest Doug?
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What's the latest Doug?
I'm building the wing (outbd). Hope to post some pics this weekend. Trying to get it up to sheeting so I can take it out of the jig.
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Gotta love the Easy Rider helmet.
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Here I am plugging along on the outboard wing section. I didn't realize till after the fact that Brodak's wing jig is adjustable. The plans assume your going to use it so the ribs end up against the board when building 4 ea. sections. I went ahead and ordered a Tower Hbs. jig - big mistake. The rods are 5/16" solid steel (sag/ heavy) and the base is 2 pcs. of 1x2 particle bd. What a POS! I made it work by buying a couple F/G driveway markers (5/16") and got the tattooed punk at Lowe's to cut me a proper base from 1x6 pine.
With the rods 2" off the board you can build each wing half as one! Join the spars carefully first making sure they match the angles of the spars shown on the plans, enlarge your rib jig holes a little - Rib 4 is fragile! The L/G doublers will have to be drilled and mounted first for the jig rods. Also enlarge the cutout for the spar splices.
Flip your plans upside down and draw a ref. line 2" below the lower edge of the jig rod shown on the plans and then draw out some templates for the inbd. & outbd. ribs. (1/8" ply) Use these when you assemble the spar to the ribs. Obviously, you'll need mark the spar/ rib locations.
I did not butt splice the trailing edge but rather used a scarf joint on each side of Rib 4 - the break in the wing. This makes the transition smooth and strong.
This is just an alternative to the Brodak system, not implying it's any better but it's working out nicely so far.
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Might be a stupid question, but why is there no inverted gull bend in the wing half that appears complete?
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Looks like the wing is being built up side down. VD~
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Look at the second picture a little closer, that's the outboard wing upside down - nice build, thanks for posting. 8)
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Might be a stupid question, but why is there no inverted gull bend in the wing half that appears complete?
It's there, just not a whole lotta anhedral/ dihedral goin' on. I think Pat Johnston flattened out the gull wing for better performance.
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Looks like the wing is being built up side down. VD~
Yup, ...and right-side up when you flip it! n~
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It's there, just not a whole lotta anhedral/ dihedral goin' on. I think Pat Johnston flattened out the gull wing for better performance.
In talking with him, I think it was equal parts that he wanted the wing to be able to be built in one piece halves,, on an arrow shaft wing jig,, so thats all the dihedral you could have and still get the shafts to be within the ribs,,
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Look at the second picture a little closer, that's the outboard wing upside down - nice build, thanks for posting. 8)
DOH! ;D Didn't even think of that, I see it now.
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Some more progress...Shear webs installed on spar and T/E, weight box, and I sheeted the last bay for torsional strength. This ties in the end of the wing. By scarfing the Trailing edge sheeting on each side of Rib 4 and adding the 1/8" strip you can get a nice smooth transition on your aft edge. The chopped tip and sheeting is next, then I'll start the inbd. wing.
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Hi Douglas!
Coming together very, very nicely! Very nice workmanship. This will be a great looking model when finished. y1
BIG Bear
RNMM/AMM
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I'm diggin' this one. y1
Thanks for the pics!
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Well I finally finished the inbd. wing half and joined them tonight. There's really no reference to index the wing halves off of except the joiners and the plans. I carefully glued the joiners on opposite sides of each wing spar then cut the spar ends back to the exact center (marked). Laid the wing half over the plans with a square clamped and aligned with the plans - spar & centerline, then marked the L/E and T/E with another square. Had to shim the T/E but it all worked out, I thought it needed some type of joiner anyway.
I put the leadout guide inbd. of rib 12 and I'll be making some stubby wing tips soon and installing the center and L/E sheeting. The shear webs end a couple bays short due to leadout clearance.
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Lookin' great! Is the fuse ready to go Doug?
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In talking with him, I think it was equal parts that he wanted the wing to be able to be built in one piece halves,, on an arrow shaft wing jig,, so thats all the dihedral you could have and still get the shafts to be within the ribs,,
The other thing is getting the LO's inside the wing and getting the LO guide at the vertical CG. Pat's got it under control!
Missed you guys at Regionals. Sinus infections aren't as much fun. H^^ Steve
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I found out embarrassingly enough they do make long pushrods threaded for 4-40, duh!
Used a DuBro HD ball link and cut the pushrod accordingly. You'll need to slide the bellcrank aft slightly to line up with the rib cutouts and trim the doublers on the gear block ribs.
I added a rub strip for the leadouts because I terminated the L/O's up-side down on the bellcrank, oops. It all worked out.
Tips are solid blocks with a 1/4" center. I wanted a little weight on the tips to possibly help in the Okla. wind, dihedral and all that.
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Is that solid wire leadouts? I quit using that for planes that did not require solid wire controls years ago. Racing was the only place that I used them when I had to. H^^
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Is that solid wire leadouts? I quit using that for planes that did not require solid wire controls years ago. Racing was the only place that I used them when I had to. H^^
Yup, .032" music wire.
I wanted to give them a whirl.
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I installed the wing and started closing up the center section. I used .75 oz. FG and old resin which is why it's yellow. The 2 pc. pushrod are a pain, it'll be a 1 pc from now on. I need to sheet the aft fuse and plan out the extended oil cooler scoops and fillet fairings.
I'm considering SIG Koverall for the wing, but no Monocote or Silkspan! Maybe Silkspan and Polycrylic for the fuse, I just can't handle the dope fumes anymore.
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Is that a Saito 40A I see in there! y1
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Nice job , Doug y1
Rob K.
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Is that a Saito 40A I see in there! y1
Yes! Great engine, which reminds me I need to get it broke in and modified by Bob Reeves. His run like a Swiss watch.
These engines have a short nose so I'm forced to install it right next to the nose ring. Hope I don't need too much tail weight.
If this pic doesn't motivate me to finish it I don't know what will! y1
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Yes! Great engine, which reminds me I need to get it broke in and modified by Bob Reeves. His run like a Swiss watch.
These engines have a short nose so I'm forced to install it right next to the nose ring. Hope I don't need too much tail weight.
If this pic doesn't motivate me to finish it I don't know what will! y1
Thanks Doug for the complement, You know Joe Gilbert won Expert profile at Brodaks this year with his T-6 running a Saito 40 with my mod to the intake. If you have the CL engine let me know and I will loan you an RC carb to use during the break in. An RC carb makes it much easier to get past the under 4k for the first 10 minutes recommendation.
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What's the latest Doug?
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Doug? ;D #^
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Please give us an update on the Corsair. Pics please.
Rick Henry
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Hello Doug,
I'd almost forgot about this one until I was looking at some Bud Light Super Corsair photos tonight. What's the latest on yours?
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Looking awesome, maybe I will see it this coming year.
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Doug,
It's been a looooooooong time, any progress on the Corsair? ???
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Hello Doug,
Did the Corsair ever get finished? ???
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Ever since I was a kid and watched the TV series Black Sheep Squadron I always wanted to build a semi-scale Corsair. This is not a Brodak Corsair but one that I designed and built from scratch that was completed near the end of 2014. Here is a YouTube video of a short test flight:
https://www.youtube.com/watch?v=TNsmYlNqlLc
Enjoy,
Dennis
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Hello? Doug? Why no response here? ???