Rise and fall of my 40% Yak54

[TheTank]

Was the rudder wag severe enough that the rudder swung far enough over to hit the elevators and perhaps breaking them resulting in no elevator?

Sorry for the loss Love the color scheme though. My comp arf 2.6m is done in that scheme.

[Xipp]

	Quote: Originally Posted by yakwrecker
	Maybe the guy didnt like how it flew and started screwin' with it and dorked it on purpose. You never know

Ha Ha thats funny it was SEG that was flying the plane when it went down, I had just handed SEG the radio and he made a couple passes with the plane and it rolled knife edged and went in at about 3/4 throttle at about a 60 degree angle (very ugly) When i was flying the plane all was fine something came loose inside is all i can think of..BY NO MEANS WAS IT A PILOT ERROR it was a mechanical failure of some sort...Sorry for your lose Warren it was a sweet flying bird

[warren cross]

40%plane,DKippen,thanks for the input,the plane had NO control at all , like a lockout,the plane went into a knife edge on its own. The rudder cables were tight,it was on a swb self adj tray. Next Yak will have servo in rear!! We did have 5 GREAT flights before the demize.

[DKjens]

	Quote: Originally Posted by yakwrecker
	Maybe the guy didnt like how it flew and started screwin' with it and dorked it on purpose. You never know

I think that's the dumbest statement I've ever heard. As in you hand your Tx over to somebody who would screw you that way?????????

Did the plane roll to knife edge on its own or was it due to pilot input?

If the rudder had been wagging previous to this, why didn't you land the airplane and check it out before further flying?

I have seen the cable in those SWB self adjusting rudder trays get pulled out of the crimber during flight, how was it after the crash?

It was a beautifull plane, very sorry for your loss, been there myself.

[Kevin Y]

Was the rudder lead or any other leads unplugged from your reciever when you got to it? I have had a rudder come unplugged in flight and it does something very similar to what you have described.

[crhammond]

	Quote: Originally Posted by warren cross
	40%plane,DKippen,thanks for the input,the plane had NO control at all , like a lockout,the plane went into a knife edge on its own. The rudder cables were tight,it was on a swb self adj tray. Next Yak will have servo in rear!! We did have 5 GREAT flights before the demize.

Sounds like PCM lockout. What were the servos set to do in failsafe? Did the engine drop to idle?

I had a couple of PCM run aways last year. One I got back just in time - the other not. I could not find anything wrong after either. Worst way to lose an airplane IMO - I feel very bad for you (and the guy at the sticks must feel like hell too.) With my big Cap I spent 2 mins in and out of lockout trying to save it only to have it hit power lines... stuff happens.

My experience is if it locks while even a little aileron is input and holds it will roll more than you expect... and sometimes it comes back just long enough to hold and lock again ... but the rudder moving is a very wierd thing. Was the crystal loose?

Again - very sorry for the loss. I hope you find the cause - nothing worse than not knowing.

[Mark Davis]

Sorry for you loss... It was a beautiful airplane...

Out of curiousity, were you using 1 or 2 Rx's???

[Shawn Berkheimer]

How sharp was the trailing edge of the rudder? Some Comp Arfs would suffer from the rudder occillation as well, the fix was to slot a peice of CF tube and glue it over the trailing edge.

it sounds to me that the rudder went into this occillation the resultant power spike was more than the power system could handle and it went into low voltage lockout.

I feel for ya, it was a very nice airplane indeed.

Shawn

[lbkyak54]

Sorry for your lost, what a beautiful plane

[sweetpea]

I wasn't there, but heard from both SEG and Warren.....

There was no control of the plane and the rudder was moving full deflection both directions on its own.

There was not much left of the plane after the crash...I've seen pictures, so I'm not sure how detailed a post crash inspection can determine.


IMHO, I think that maybe the batts failed or the RX (very rare for both to fail) thus causing the servos to lose voltage.

The rudder moving can be explained with failed or no power to the rudder with the self adjusting tray as that is the point of it. So the servos don't fight each other (hence no match box on it).

No matter what, this plane was awesome. I saw it on the first day. And that 3W157 (even though it wasn't a CS like Mine!) pulled that plane around like no one's business.

I'm there for you Warren if you need any help on the "new" Yak you build

[bodywerks]

	Quote: Originally Posted by DKnippen
	Hey Warren, it's a bad day indeed. The only thing I can think is the first few flights is your new rudder cables will probably stretch the most. Then if your horns in the rudder are too short you wouldn't have enough leverage to keep that rudder from fluttering...Just a thought. Sorry

That's a good possibility. I also personally saw this happen with a guy that had a gyro in the rudder control system. I don't remember what it was but I think the gain control went haywire. I don't think Warren had a gyro, though.
By chance, were all of these flights on the same day? On your next plane, I would definitely only fly it once, twice at the most, and then take it home and go through it for just such a reason. I do this on my big stuff every 2 flights for the first 10. I take off the cowl, check everything under there, check for wire chaffing on the airframe, loose cables, glue joints, etc. I would rather dork in a plane than to have something on it fail that I could have possibly prevented...

[JeremyHolt]

Sorry Warren.. you will just have to make the next one even better.