combatpigg

My Feedback: (3)

I've had good results making 1/2A speed planes with solid balsa sheet, so my curiosity got the better of me, and I decided to try it with a .32 powered plane. The wing is made from 3/8" balsa and it has about 280 sq inches. The planes weighs 2.5 pounds RTF before covering. Right now it has 3/4 oz cloth and water based polyU everywhere, it would be nice to just mist spray some color highlights on the top of the wing and just go with the polyU for fuel proofing, but I'm leery about polyU being fuel proof. The only controls will be elevator and ailerons, handled by HS 225 servos and a HS 55 for the throttle. The OS .32 isn't the easiest engine to pack into a cowl. This cowl is 2 piece made from fiberglass cloth and medium CA. It will get painted with K&B epoxy paint. I figure the plane will be easy to launch and fly, but with only 280 sq", it might be a brick to land.

willflyforfood

I like it!!! This is very similar to what I am building for my OPS .21 except I am using foam core sheeted wings, but thats an Idea I might could try, I think it would be a lot simpler.

willflyforfood

One of my problems is trying to find a small aluminum spinner, with the 7x6 prop I cant find one small enough.

buddude8

My Feedback: (10)

if you want a good clear cote that is fuel proof try u-pol. You can get it at any automotive paint supply. goes on easy and dries quick. it is in a orange spray can. It also works with water based paints.

combatpigg

My Feedback: (3)

BD8, thanks for the tip, I've got some great suppliers near by.

WFFF, I ran my .32 for years at 18,000+ with plastic 2" spinners, I don't think the forces on a 1.5" spinner at 22,000 would be much different. The plastic spinners I get from Great Planes have 4 locking pins and a pair of screws to hold it together. The spinner on this plane is 1.75", don't recall the brand, but it was only $7.50. Thought that was a good price.

Here's another look at the plane in progress. Not too stylish, just as simple as I could make it and have it aerodynamically clean. The cowl has as much time in it as the rest of the plane [>:]!

willflyforfood

Sure does look good though. I have the exact same design concept as yours, simple and clean, square fuse basically with nicely rounded edges, cowled engine, nifty wingtips and all that jazz. Mine is a low wing though. If I ever get mine to a point where it looks like a plane i'll get some pics up, I have lots of irons in the fire as always though...

bob27s

My Feedback: (19)

Very nice

combatpigg

My Feedback: (3)

Well, here goes another attempt to upload something bigger than a postage stamp photo of the planes' progress.

After using a few coats of WB POLY U to seal the 3/4 oz cloth, I sprayed on some TOP FLITE paint that is supposed to be fuel proof up to 15%. Then I sprayed that U POL stuff on......it sure smells powerful! That's about it, this plane cost very little to build, there's nothing "trick" about it, kind of plain looking, but all it has to be is fun and hopefully fast. That OS .32 has been a lot of fun, I just replaced the rear cover after a crash last summer and the engine felt tight. After about 30 seconds of facing the cover with a wet stone, the clearance between the crankpin and cover is where it should be now.

It is amazing how quickly the space inside the plane gets filled up with equipment, thanks to todays' mini sized gear, it is barely practical to built a speed plane out of balsa instead of fiberglass, and still be able to keep the design in the front view within the confines of the engines' outline. All that is left to do is paint some white stripes to the top of the wing and fuel proof them, then check the CG, it is within reason now, some more coats of U POL to the tail end should dial it in

Well, that does it for me, I just tried to upload 2 stamp sized photos and RCU says that the file is too large.......have a nice forum.

dieFluggeister

Hey CP, I really like your sheet wing concept for this size of plane. Could you tell us if you used your glue-spar method (once or maybe twice per wing) and how you did your airfoil?

Any thought of going with an inlayed CF spar?

combatpigg

My Feedback: (3)

Hi, DF! I don't believe in the glue joint spar, I always use a little bit of spruce or hemlock. The C/F spar isn't really needed unless the anticipated speed and wing loading is foing to be greater, at least that is my belief. This wing has a wrap of 4 oz cloth in the middle 6 inches, and the whole wing is covered with 3/4 oz cloth, so I couldn't visualize a .32 powered plane that weighs 2.5 pounds needing more. If I build a similar plane for my WEBRA .50, then C/F might get considered, or add more spruce. This plane is fun to fly, it is running a 7.2x8.6 and I would put this thing in a vertical drag race with anything that is prop driven. It isn't as impressive to watch as a DIAMOND DUST though, just looks like another plane out there. I'll get it clocked in a couple of months set up to run on high enough nitro to get the rpm close to 20,000 with the 8.6 prop.

BTW, the "airfoil" is flat bottom, the top is rounded and the high point is at the 40% chord line. The work goes quickly with a razor plane and sanding blocks set up with 80 and 120 grits. There's only so much work that I'm willing to do with a 3/8" sheet of balsa .