..

Good to hear that you got it in the air and like the way it flies. Too bad about your gear. I'm going to likely go with either the Gator R/C gear or the Graph Tech Bolly gear. I have a pair of Integral gear legs, but don't really like the curved look of them for this airframe.

I'm not sure that will be enough. Well, depends on which kit version you have. From what I can tell, there may be three versions of wing structure. The earliest had a box structure around the wing socket tube, plus incorrectly installed shear webs. There was talk of the factory improving the wings with correctly installed shear webs and other changes, and then there are the latest versions available now. The latest ones don't have a box structure at all around the wing tube, plus shear webbing with the grain the wrong direction. Definitely a disaster waiting to happen. If your wings are this version, I don't think the foam will be enough.

OTOH, why not build a foam wing for the model and toss the balsa wing? Yeah, it will set you back some green backs but will greatly reduce the possibility for a failed wing. Chances are good that the end result will be lighter than the balsa stick one. This model is inexpensive enough yet flies well enough as is to where an additional couple 100 won't kill the wallet.

Could someone please tell me the size of the wing tube for the Evolution (latest version). TIA Larry

It's 25mm. I'll measure the length too, forgot to do that. I'll post that info soon.

Thanks pshark101; I'm working on a Dave Snow wing for a Lightning and it uses a 7/8'' tube..... Just my luck. I keep looking at the site and they're still on sale for $229; hard to pass up if you don't mind alittle work.

You're welcome. The length is 495mm (~19.5"), just FYI.

Yeah, I think it's really a great deal. The big thing of course is beefing up the wing structure a bit, but it wasn't bad... actually kind of fun to do. As long as you've built a couple of kits before it won't be a problem. The rest of the wing is built really solid. All of the contruction, glue joints, and covering on the plane are really nice. Seems the canopy was even changed from the original kits, it's tinted now and the plastic has an adequate amount of thickness in my opinion. Lots of complaints about it being too thin on the early examples. The only other thing to change is the landing gear, pretty simple to do too. One other minor issue, I had to trim a bit off the top of the firewall so that the cowl would slip over, took a few minutes.

I installed wing and stabilizer adjusters, installed custom landing gear and added shear webs, I am using an E-Max 5035/08 motor on 10 cells and an APC 19-10 prop. I built a custom adjustable motor mount. I set up the plane by the triangulation method. It is balanced at 27% MAC. I am very happy with this set up. This is my first pattern plane although I have been flying over 30 years with all types of sport and racing planes. This thing will do a knife edge loop with rudder only!. My problem is I don't trust the wing so I am going to take Matt's advice and build new wings. My question is does anyone have suggestions for airfoil and plan form?. Although the OE wing works good there must be something better now.
Thanks
Ray

Ray,

My favorite airfoils for Pattern planes are NACA 0010, 0011 and 0012 (10-12% thickness) root and tip. Use the same planform as the original wing. You might want to use 12% at the root and 11% at the tip (or even thinner 10%), for very spirited performance. I knew a guy here in the NE who cut incredibly accurate foam but I think the guy has passed. Try for a reputable source of cnc cut foam for best results.

If someone finds a good wing source, share it. If so, I might spring for another Evo... The plane flies good.....just was impossible to get it under 5000 grams.

Thanks for the input MTK. big-G, my plane is heavy too. By switching to 4000 ma batteries I could just make weight but I would hate to loose flying time for practice. I get 8 minutes now with average of 3000-3500 ma used. I have 2 5 cell 5000 packs 25c. It flies well enough and no one weighs them at contest around here so I am going to leave it as is. I have a lot of time and effort in set up and trimming. To change weight would mean re balance and trim. Not practical to change between contest and practice. I hope the new wings will bring it closer.

Thanks
Ray

bump

Funny you did that, I was just re-reading what others have posted about the wing, I was just about to throw them into the trash and buy new wings when I decided to tear the bottom sheeting off and look at the construction. What I noticed was worse than I thought it would be but I think it can be fixed rather cheaply.
The issue with the failure is the center line length wise of the tube moved away from the center line of the spar, in the design used by the manufacture there is nothing I could note to prevent this from happening. Every wing out there built like mine will fail eventually. The first movement of the tube center line is microscopic each following movement will be greater until catastrophic failure occurs, this could happen in straight and level flight. In better design wings the tube is locked in place in the center of the spar. (This is basically the conclusion already discussed here)

So what to do about it?
If one picture is worth a , well you know.

R4 is the new end point for the tube R3 is factory location.
S1 is a 1/16" ply shear web extending from R3 to R5
R4 is 1/8" ply
The key is to lock down the tube tip at R$ so it cannot move off center.

questions?

I'm building this for the fun of it not competition, those days are over, power will be Dle 35RA with muffler.

yup,

My wings are the same. I have already removed covering from one of my wings to confirm. I don't know what version I have. I bought the plane NIB from a club member two years ago for 150.00 and it has been sitting since then. Just getting around to it. I like your extending the wing tube. I will do that as well as adding additional shear webs with the grain running vertical. Did you have an extra wing tube? if not were are you going to order one from?

I bought a 1 in. dia tube from Graph Tech and cut it to 32 in. long. This allows it to but to spar. No wing sheeting needs removed. The spar is not what fails, its the short unsupported wing tube. The short sleeve pieces are from my first failed wing. Don't worry about the sheer webs. I did a lot of research and found the forces on webbing is diagonal so grain direction is optional. My plane has done many snap rolls and aerobatic flying without problems after modifications. Even though I had to buy 2 airplanes and a $50 wing tube it was worth it. I did a very accurate set up and trimmed by the Triangulation Method resulting in an excellent flying airplane.
Ray

Ron did you get any experience running the DLE? It's a good engine and has ample power for this size model.

Glad you figured out the problem and fixed it. BTW- what's the rib spacing in that wing?

As an aside, I just completed the tooling for making built up wings (of my design). The panels are fairly large (470 sq inches) but exceedingly lightweight (170-175 grams per panel). My rib spacing is 2 1/4" (16 ribs per panel). My target is 12 ounce RTF with servo and linkage weight, fully painted.

Matt I did not run the DLE 35 yet, I was going to pick your brain first. The rib are spaced 3.25" apart. What is the best exhaust option for the DLE? I know you wrote it some place so I wont feel bad if you tell me to look it up LOL. I still intend to use the soft mount I got from you. Will your wings be available in some form?

Ray your fix is perfect if buying a new tube, its what I wanted to do, the rib does not need to be replaced if the tube reaches the spar. My tube cost nothing it was the remains of an old plane, it is a little to short to reach the spar but was very workable. I think between your photos and mine others have a good solution to the problem , thanks for the photos. You are correct , new shear webs with grain in any direction is a wast of time, the spar is plenty strong.

Just a point to consider, locking the tube end to the spar is not a perfect solution. The spar is strong enough for the job intended. With the tube end locked to the spar the tube end will act like a pivot point for all of the wing load. All wing load will be transferred to the root connection of the tube not the root of the spar. Hopefully this goofy setup will be strong enough for what we use it for. Just think, a little good engineering and this wing would weigh less, be easier and cheaper to make and stronger... unforgivable!

I forgot that I sent you a soft mount for the DLE. You may want to start break in when ready using 40:1 gas oil mix. I prefer and use synthetic oil. I use Bel Ray MC1, but many use Redline, Stihl Ultra, Pennzoil, etc. They are all excellent oils

I used an Xoar 19x10 laminated wood prop but anything from an 18x10 to 20x8 will work on muffler or canister. A pipe will produce extra ponies and mid range torque of course, but I didn't use a pipe of the DLE, only the can. The settings for break in were about 1 5/8ths on the HS and 1 3/8ths on the LS needle. It doesn't need to run rich during break in (not a glow engine)

The header I used was the standard MACS for the OS140. The holes were drilled out to 5mm; a convenient solution.

On the wing, not sure yet. If I can get someone to write me a laser cut routine, then making the ribs will become trivial. Right now I have to trace each rib using the tooling I created, carve every rib by hand and use the tooling to true them up. It's very time intensive. A labor of love. On the other hand, shaping each rib on the tooling builds in the correct angle of the rib edge to follow the wing panel surface angle. A minor point and it makes no difference to the flying, but what the heck, it's for me.

The wing tube sockets are built up; it's simple 1/32" balsa sheet that's been glassed on one side and cured. Then it's wetted and rolled onto the wing tube and dried, glass side in. The fit is custom of course; snug but not tight. Then the balsa is wrapped with carbon tow on bias and is doped in place. About 3 coats of nitrate dope is plenty and weighs almost nothing. Very strong and super light (about 6 grams per foot of socket, so 12 grams total for both sides). The carbon tow is not necessary if the sockets are put in foam wings, but my wings are built up so they might need a bit more strength and stiffness.

Don't mean to highjack the thread so I'll stop there

Thanks for the info Matt