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Curious Wing Construction - Fairchild 24, Del Gatto on Outerzone

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Curious Wing Construction - Fairchild 24, Del Gatto on Outerzone

Post  PeterJGregory on Sun Feb 14, 2016 9:56 pm

I started building the Paul Del Gatto Fairchild 24K for a build contest on another site.
This model has an interesting wing. Sheet 3/32 with no span-wise spars. Just semi-ribs to hold the shape of an airfoil as you bend the 3/32 sheet.

http://outerzone.co.uk/plan_details.asp?ID=6152

Thought I came up with a cool way of building by first tacking the semi-ribs onto Dollar Tree Foam Board DTFB.
Getting a curve in the sheet of 3/32 was fairly easy - some heat off a couple of electric burners on my stove, and some H2O via a spritz bottle.

Things worked 50/50 OK. I think I can keep moving forward with what I have.

I used Gorilla Glue brand wood glue on the ribs to top sheet.
I weighed the sheet down on the ribs with bags of rice and popcorn out of my pantry. Kind of made "sandbags" with the stuff and it conforms to the desired shape of the top sheet.

However, after a couple of hours there must have still been a fair amount of moisture in the wood because I lifted the wing, the tack strength outdid the rib to sheet strength on a few of the ribs - they remained stuck to the DTFB.

Also, there was a significant spanwise warp, downward(!) on the wing tips.

Actually, as it perhaps continue to dry it seems to maybe straightening out.

Here's some pics:






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Re: Curious Wing Construction - Fairchild 24, Del Gatto on Outerzone

Post  pkrankow on Sun Feb 14, 2016 10:12 pm

http://outerzone.co.uk/plan_details.asp?ID=358

It is pretty popular for small builds. There are a large number rubber designs that use this technique. The wing is surprisingly strong.

I like the foam board idea, but might instead be tempted to glue it straight to a glass on my desk with some dental floss under it to cut the glue out.

Warp free is paramount of importance to any wing.

Phil
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Re: Curious Wing Construction - Fairchild 24, Del Gatto on Outerzone

Post  PeterJGregory on Sun Feb 14, 2016 10:23 pm

Thanks Phil - glass sounds like a good way to go. The wing is off my "board" now so I'll see over the next few days what happens to its warp. I'll just start over if it isn't straight - didn't take much time.
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Re: Curious Wing Construction - Fairchild 24, Del Gatto on Outerzone

Post  pkrankow on Sun Feb 14, 2016 10:45 pm

I built a pageboy, and used a bunch of soft cover books to weigh the wing down to conform to the ribs. I started by gluing the straight portion of the rib on the flat wood, then after that dried gluing the curve and loading the books. It worked pretty well. It was quite a pain though.


Phil
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Re: Curious Wing Construction - Fairchild 24, Del Gatto on Outerzone

Post  JPvelo on Sun Feb 14, 2016 11:02 pm

Peter,

Can I ask what site you're building that for? Looks like fun.

Jim
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Re: Curious Wing Construction - Fairchild 24, Del Gatto on Outerzone

Post  PeterJGregory on Wed Feb 17, 2016 5:08 pm

RCGroups - http://www.rcgroups.com/forums/showthread.php?t=2515874

The YOBBO Contest - Year of Birth Build Off (!) I give away my age with this one, born 1963.

This is another design that starts telling me the builder about how great the designer is/was. We'll see how light I can keep electronics and battery. That is why I originally designed for 119.63% scale up - 19.63% increase, get it - wanted to try to increase the wing area. Hopefully increase wing area faster than weight added, to reduce wing loading as I go. Well, I'll save all those gyrations for another build of this one, in the future. Decided to go with the .020 Tee Dee. Hope to bench run the one or two I have this weekend. Certainly should be close to finishing by Mon morn.

Cheers - Poughkeepsie Pete
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Re: Curious Wing Construction - Fairchild 24, Del Gatto on Outerzone

Post  pkrankow on Wed Feb 17, 2016 7:38 pm

I noticed in the linked thread fear of dope warping. Spray polyurethane did not warp anything on my pageboy.

Phil
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Re: Curious Wing Construction - Fairchild 24, Del Gatto on Outerzone

Post  PeterJGregory on Fri Feb 26, 2016 8:59 pm

Need to finish this plane up, but going to WRAM show tomorrow. Decisions, conflicts - ugh.
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Don't Ever put a project down before you are finished(!)

Post  PeterJGregory on Sat Mar 19, 2016 10:54 pm

I got back underway today on the Fairchild 24K, and pretty happy with the progress. Everything behaved well, no "gotchas" and I am hoping another 8-10 hours to be ready to fly.

This is a very light old FF design - pretty fragile for landings without any remote control. The tailfeathers are only 3/32 balsa so I added carbon fiber rod as trailing edge to the horizontical stab and the leading edge of the elevator.

The wing called for "cloth tape" at the center joint but I went a little stronger and used fiberglass and 5-minute epoxy, most of which i intend to sand off tomorrow.

I really hoped to get some test runs of the engine(s) today but I ran out of time. I have two used but new-to-me TD .020's, neither of which I have run. If family obligations don't run at high priority, I may be able to use some of Sunday to move ahead some more.

Fiberglassed center wing joint.


Carbon fiber edges on horizontal stab and elevators. Hopefully, not too much weight added but these surfaces are fragile and vulnerable.

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Re: Curious Wing Construction - Fairchild 24, Del Gatto on Outerzone

Post  MauricioB on Sat Mar 19, 2016 11:14 pm

hi! ... how nice job !, it is a circular flight pattern or will build for radio control? Smile ..Mauricio.-
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Re: Curious Wing Construction - Fairchild 24, Del Gatto on Outerzone

Post  PeterJGregory on Sun Mar 20, 2016 4:10 am

I am converting this plane from Free Flight as it was originally designed, to Rudder-Elevator RC. At the moment, I am planning on using an OrangeRX 615x receiver, 2 x 5g servos, a small BEC, and a 500 mAh lipo.
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Re: Curious Wing Construction - Fairchild 24, Del Gatto on Outerzone

Post  getback on Sun Mar 20, 2016 9:25 am

Cool good to see you are able to get some time on the build, Look's like to be a nice easy glide flyer. Good ide on the fiber rod , was in the w-mart the other day and almost went back to see what they had but, was hurting sooo bad I just couldn't force myself to it . getback RC Plane
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Re: Curious Wing Construction - Fairchild 24, Del Gatto on Outerzone

Post  pkrankow on Sun Mar 20, 2016 11:57 am

The CF rod is likely stronger and lighter than other options. It also glues exceptionally well. Good idea.

Phil
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