First flight of new yak 54 56. Flight was going good just standard flight getting feel of plane bout 5 mins into flight ailerons started fluttering and lost control of plane. got to inspecting aileron servos the nylon gears were stripped. they were brand new jr st47 servos. thinking of going to metal gear servos and got me worried bout rudder and elevator servos as well. any suggestions?

I presume that it's a 56-powered plane? What size servos did you use? Are they standard size? I've seen some planes of your size call for mini servos, and that scares me. If you have standard sized servos (40-80 oz/in of torque and a hefty servo arm), the gears should not have stripped, even nylon gears. This presumes that your hinging and linkages are good. If you had flutter, the flutter probably caused the gears to strip, not the other way around. I'd make sure that you had a good no-slop setup with your hinges and linkages first.

Of course, metal gears are better (and a bit more expensive). But, if you have a flutter issue, even a metal-gear servo won't help.

Just my humble opinion,

Bob

yes i was using jr sport st47 servos. it was flying fine and no slop what so ever in linkages. thats good point you have made but what got me plane flew very well for 5 mins or so. The st47 servos call for up to a 90 size plane.

Yeah, the ST47 should have been good enough. Did you hear a buzzing sound while the plane was flying (i.e., flutter?). Or, have the servos been apart before? How about the hinging?

And, how was the battery? If the battery was weak, it could have contributed to the crash and the servos could have been stripped as a result of the crash.

Just trying to help narrow the possibilities down.

Bob

Thanks i need the help cause dont want to happen again.  The servos where brand new just installed on plane. battery was fully charged. the radio sysem is brand new.  It was first flight on everything. I seen nothing out of ordinary on flight it was doing great.  I flown at full throttle no problem i was at half throttle just doing standard flight when this took place.   The plane done a spin out in air and could not recover it . throttled back thats when i seen aelirons fluttering. By the way they where flopping they stripped in air.  the wing was not damaged in crash.  hinges worked great.  i done alot checks on plane before flight. But ya never know might have over looked something.  I have crashed my share of planes but never had a mechanical failure like this. Only thing i can think of aelirons on this plane are much larger than what i have flown in the past. Just wondering if standard nylon servos are not the way to go on 3d planes

I see what you mean. I looked up the plane and found a reference to it on eBay (not that that means a hill of beans). Other things that I can think of are, perhaps, the routing of the antenna. Was it near a servo or servo leads? Sometimes the digital noise of the servos can get into the rx though you said that the radio was new.

After looking at the plane, the ailerons don't look that big that they'd strip the servo gears.

Right now, after re-reading your first email, I'm thinking that the antenna might have been routed near a noisy servo, or perhaps the Rx was defective. You said that the servos were JR, so they wouldn't be likely to pick up noise the way some bargain basement servos might.

Was the engine somewhere in the range of what the plane expected (i.e., a 46 - 60 range?) or was it perhaps a .91? Other things to consider are, did Vibration get into the Rx? Or, did the Rx break loose from its mount and put a strain on the antenna wire or servo wire, breaking it?

I wonder if other people monitoring this thread might have some ideas???

Bob

Only thing that got broke in crash was tip of wing and frt of fusealge. no damage to reciever.  im running a 60 nx evo motor.  I thought bout what u mentioned bout antenna .  that was possible to me to.  but i routed it as far away as thought i could.  </p>

Hmmmm, there has to be something there... There is something that we're taking for granted that we shouldn't, something far-fetched like the wing not bolted on securely, but you would have noticed that when you disassembled the plane after the crash. Is the aileron warped? I'm really reaching for reasons here....

I'm still curious about the Rx... not that it was injured in the crash but that something might have failed, but that is also a far-fetched idea... that's not too likely to cause flutter.

And yes, to go back to your basic premis, if the plane was flying fast and asked to manuever sharply, those nylon gears could strip. But I am still of the mind that they are the result of the flutter, not the cause.

Bob

Check the aileron gap if there is ANY seal on the bottom side with clear plastic tape, and a little flutter will take out a set of gears in about 1/2 of a secound

been there done that

Cheers Bob T