SCOTT42

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I was fly yesterday afternoon, I was on my 2nd flight of the day and all of a sudden my wing comes flying off while in flight, I was at full throttle about 40 ft up when it happened. All I can say is WOW! What a lawn dart it turned into quickly. Not sure whats next think I may buy another fuse and rebuild it as the wing is in great shape still.

AA5BY

Sorry about the loss.

With both rear wing bolts losing their heads... a suspect is the leading edge of wing became unsecured. Two possible failure scenarios... the double rib leading protrusion broke or the pocket in F-2 failed. If the protrusion is still in tact on the wing, then it was a failure of F-2. If that is the case, the F-2 pocket needs added strength.

SCOTT42

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We arent certain what give? The f-2 is intact and the double rib stab that goes into it is intact, now it looks like that the double rib stab is mising just a very small peice of wood from the very tip and we are thinking thats what give. Ill try and get pics of the wing and the F-2 former later today once I get up and moveing.

kenh3497

Or tightening the bolts to much stressing the head to failure?????

Ken

AA5BY

Yeah Ken, that is a strong possibility I'd not thought of. Or... the nylon bolt heads simply gave from a high G load on the wing.

If the front of the wing came up first, there ought to be evidence of the bolt heads stressing the bolt holes in the wing.

If the bolt heads popped off, then the holes will likely show no or little sign of stress.

SCOTT42

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I really dont think thats what happened becouse I seen the leading edge lift up first, allso if you look at the pic of the wing where the wing bolts mounted thrue you can see where they pulled and left marks against the wing.

AA5BY

Yep... the pics seem to indicate that the front of the wing broke loose with the strongest evidence for that the indentations at the TE that were left when the wing rotated up.

Last Thursday, I was flying a Das Box Fly, a small biplane with a .30 Saito. The wings are held by rubber bands and I used the normal number of three at each location so twelve in all and put it up. I noted quickly some zooming with moderate elevator and reduced power and brought it down safely and added six more on the top wing.

The batch of rubber bands were not as strong as those normally used. I'd mentally noted their weaker strength when installing them but it didn't sink in that they were inadequate. I was fortunate. Ironically they were ones that I'd recently gotten at the hobby shop whereas the previous couple of packs that worked fine were from the office supply.

SCOTT42

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Shes gonna be missed, I loved this plane. Im gonna order a new fuse for it and rebuild.

SCOTT42

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What has really been bothering me is that about three weeks ago I had a very hard prop strike on the runway and it pulled my engine and firewall completlly off of the plane. I had since rebuilt it, I had epoxyed the firewall back in place, replaced the bottom sheeting and reinforced the firewall with fiberglass. I just cant help but wonder did I miss something? All was flying well when it happend. Who knows at this point!

AA5BY

The attachment to a stick is understandable. I fly an Ultra Stick Lite with a Zenoah G-20 and it is my go to plane that gets flown as much as the rest in the hanger combined. It stays on float charge so is always ready and is the plane of choice if it is windy or the time at the field is limited because of its easy quick setup.

As well, sticks are a blast to fly and as mine is gas it is very cheap to fly. I stuck it into the top of an oak tree once and a limb tore completely through the wing. I went to reorder and they were discontinued so it was rebuilt with significant effort. A short time later they were offered again and one was laid up NIB and shortly after they were discontinued again. It is my favorite plane. And... because it has crow mode, it can be flown at the grandkids farm as it needs very little runway. The old one is getting beat up a bit but it seems that just makes it more fun as there is no over concern to protect it.

Best of luck with replacing and getting your stick flying again.

cutaway

If I was a betting man, I'd take odds that the bolts flexed back some allowing the front key to pop loose. Since the blind nut plate doesn't extend up flush with the wing bottom, there's a significant length of unsupported nylon bolt that has responsibility for keeping the wing forward and in the key. All it would take is for the wing saddle to be slightly slick with oil and the wing could have shifted back just enough to pop loose. With most of the drag being in the wing, and all the forward thrust on the fuselage, the rearward pressure on that unsupported section of bolt ccould be significant.

I'm not averse to nylon bolts, but the commercial stick designs seem to want to force them into a bending stress mode they really aren't intended to resist with any gusto. With a flush mating surface, the bolt wouldn't flex back, unless the holes were so old and whupped there was a lot of slop/play.

SCOTT42

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Well I finally had the heart to go and strip the plane of all good parts, while going thru everything I discoverd I need a new engine block, os .61FX, where the carb mounts it broke at both screw holes, allso lost 2 servos. Receiver seems to be good, passed a bench test but still need to range test it. So this is not a cheap crash by no means.

AA5BY

Sorry to hear that. A recent local crash was as bad. Engine block, two servos and receiver were destroyed. Like yours, his wing popped off and like you... all he really has left is the wing.

flyingagin

I lost y .60 stick when I hit a garbage dumbster on approach. Lost the engine and all of the airplane.
They sure are a fun plane.
From .25 up I am using 2 arrow shafts that tie to the center spar and leading edge and then into holes int he bulkhead in front of the wing. I make sure that I reinforce the part of the bulkead were the shafts go into and extend the reinforcement all the way to the bottom or the top if a low wing. On some installations I epoxy a close fitting Hard wood dowl inside of the arrow shaft. Overkill? Sure is, but it sure works. And the nylon bolt blocks are always FLUSH with the wing.
I have had the same expearance as AA5BYabove. Added more rubber bands.
Now none of my planes use rubber bands. Look ugly.
Good luck on getting the bird back in the air.
Show us the pictures when she is back togeather again.

SCOTT42

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I will post the rebirth or rebuild or what you might want to call it. But its gonna be a while Im sure as Ive got to many other projects to finish first.

Live Wire

If the wing bolts vibrate loose the wing will slip back anough that it will pop out and up and over which will pop the head off the screws and leave the marks you have on the wing. Don't ask how I know[:@]

dignlivn

Sorry for your lost,


I first heard about this problem 3 years ago or more on the 40 size stik.
I had a 40 size then and reinforced the front Tab on the bottom side with
1/4 square hard wood about 3 inches long. I now have the 60 size with
an OS 120 4 stroke, so the first thing I did after joing the wings was to
repeat the reinforcement of the front tab. So far alls well and I ring her
out on cuban 8's and reverse cuban 8's. she's a blast to fly.

By all means rebuild yours and try the hardwood re inforcement,

Bob

Bobhend

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OK so this is a late post, but I love my Stik 60 and will take a closer look at the wing hold-down. I use those black nylon bolts by Great Planes in all my planes, The main reason is the hex head, but I trust these more than the white Nylon bolts. The white nylon bolts come from many manufacturers and I have had some of them fail when they should have held. They age, can absorb moisture, and are embrittled by cold. I would replace any that show signs of age or hardening. I also put a taper on the first few threads because some planes have difficulty getting the bolt aligned to get it started.I use a cordless screw driver with a socket and I torque the bolts down really snug.

aa2dd

Hi guys

Last tuesday i was flying my stick 60, doing touch and goes. had done several and on the last one, landed, came to stop. started throttle up, and the front of the wing came up, flew off and landed next to plane. when i brought the plane and wing back and looked things over, found that the front hold down on the leading edge of the wing broke off and let the wing fly up. how lucky can you get? i had been doing loops, rolls and touch and goes, and it decides to break on the ground!!!!!!!
going to get another wing and this time when i glue the wing together, i am going to glue some carbon fiber tape between the leading edge pieces for little extra strength!

Bruce
aa2dd

Bobhend

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Bruce,
You have to wonder about the quality of their plywood. According to Bud Nosen Models, importers of birch ply, there is only one factory left in "the world" making the thinner thicknesses of Baltic birch used in models. That begs the question, are ARF factories in Asia importing and using the Finnish aka "Russian" birch ply or do they have their own plywood manufacturing in Asia, S America, Africa or Oz ? What sort of tree is it made from ? Someone from Australia should know the answer. I suspect "the world" mentioned above is only refering to north of the equator.

By the way, all the ply from the factory in Finland is metric. Anything you buy in inch sizes will actually be metric. Generally it will be close but the "3/32" " is only 2 mm, substantially thinner.

That wing retainer is the most highly stressed plywood I can think of and maybe adding some aluminum would be better. I like the idea of using two aluminum arrows , mentioned previously.

Bob

mikeh251

Was flying a rebuilt PT20 couple weeks ago and the wing popped off way up high!!! Lawn dart to the max but the wing just kept rolling over and over as it slowly fluttered to the ground. Must have had good lateral balance as it fell 100 feet and rolled 50 times without ever changing course. Anyhow, the fuse was pretty beat up but I rebuilt it. needed firewall repair, vertical stab and a new rudder as well. The wing initially looked like it broke at the rear area where the 2 wing hold down bolts are. however, when I looked closer when repairing it, I saw that the front dowel was loose also. I really believe that the front let go before the rear. All is repaired now. Just thought I would mention a similar case where I am pretty confident that the front failed before the rear. I believe that is probably what happenened to your plane too. Sorry to hear about the excessive damage you saw with the motor and all that. Your fuse looks pretty bad too. I bashed my pt20 trainer kit quite a bit, so it is alot more like a stik than a trainer, so I know your attachment and feel your pain. Hope you can get her up and going again!!!!

aa2dd

yes i agree. i would much rather see couple of dowls holding the leading edge down than the crappy plywood. I stiil can't believe that the thing broke when i started throttling up. It twisted the rear blind nut plate out of the fuse, but their lack of glue useage prevented any fuse damage!. Luckily, no damage. Cant wait till i get the new wing. I love flying that plane. it's a blast

Bruce
aa2dd

Bobhend

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Bruce,
On my BS60 the entire servo tray came loose due to insufficent glue. Fortunately I have the R &E servos in the tail [for balance], leaving only the engine servo, at full throttle. I flew it until it ran out and landed. With a Magnum 4s 90 it balances perfectly with standard servos in tail.. On my BS40 I had a major crash and built an entire new front fuse. I shortened the fuel tank area by maybe 1 1/2", put the servos in the tail, put on K&B61 2S and again, it balances ! To hold the wing on I made two of the plywood projections and widened the slot in the fuse.Anyone starting out with a new BS40, the OS LA46 is perfect for it and results in a very light, east to fly and land aircraft. I suppose likewise an LA 65 would balance a BS60. Gads, an LA65 is now $ 129.00 !! BTW the LA series engines are great. The power of the LA65 is equal to the FX 61 [published tests], On the 46 size I am not sure, still looking for data but I think the AX 46 has the edge over the LA 46. The LA engines are substantially lighter.
BH