This thread is strictly for existing owners and past owners to share there crash stories and what caused the crash of there E-flite Carbon-Z Yak 54.

By running threads like this, we as R/C hobby enthusiastic can let the R/C industry know that we do talk and will not put up with poor quality.

Please describe the crash, 1 good picture, witnesses, conditions, any testing, manufactures response if it applies.

Now lets talk!

I will get the thread started with a a quick post.

My E-flite Carbon-Z Yak 54 has crashed 2 times now from E-flight elevator servo failure. 1st time Horizon replaced a E-flight aileron servo and the wing at no cost, refused to replace the entire BNF.

1st flight after repair, YUP! did an entire IMAC basic pattern two times, setup for approach - straight and level - no elevator! had two veterian R/Cer's watch the whole thing, they confirmed and said they watched the plane and me at the stick. Receiver was disconnected so could not check for signal. Range tested -Ok.

I returned the entire BNF to my local hobby store, still waiting to hear if they will replace.

Now I can tell you, at my field, this is the second Carbon Z Yak 54 E-flight servo failure. Another guys, aileron servo failed -BAM! it to went in hard.

I will keep you posted of the out come.

(side note: H.S. owner was as upset as I was, they could have, at least replaced the tail servo's the first time.)

I wouldn't call it a crash, but mine was all squarrely on the elevator. I attributed it to the excessive wind. It was finally a nice day here, but windy!

But when I landed I noticed the elevator servo would not center it would go like half full up to half full down, then move around a little more after I stopped moving the sticks.

I looked online to buy a replacement and its like 36 bucks! Anyone know of a cheaper replacement? From reading this thread, it sounds like this particular servo may have some problems...

I crashed my Yak yesterday.
It was my 4th flight, the 2nd of the day.
I was flying for about 2 minutes, then pulled into a high stall and nosed her over.
At that point I had no control over anything and the plane came down nose first from about 150'. I was in total disbelief and still don't know what went wrong.

A couple of other pilots said they would disable the on-off switch on theirs, thinking it was one more thing that could go wrong.
Another pilot said he would add a remote bec. Both good ideas.

I wrote to Horizon and am waiting to hear back. I'll probably have to buy another one, modify it per above and try it again, ouch to the wallet!

No picture because a debris field is a debris field.

One was due to letting the airplane get too far away and losing orientation. The other? I zigged when I should have zagged.

Both my fault.

UPSIDE: fuses are relatively cheap.

DOWNSIDE: no more fuses available 'til May.

Glad I bought two extra fuses.

I like the idea of the "on/off" switch, but mine has already come loose from where it was glued. Think I'm just going to take it out as others have suggested.

On to the servo failures. Scary! But I thought this servo had been in Eflite's line up for a fair amount of time? Are there other reports of failures with this servo on other planes?

Don't think I should need to upgrade servos to feel safe, but will if I have to...

Think these posts regarding motor mounts is relevant here...

Originally Posted by SF Sloper

I crashed my Yak yesterday.
It was my 4th flight, the 2nd of the day.
I was flying for about 2 minutes, then pulled into a high stall and nosed her over.
At that point I had no control over anything and the plane came down nose first from about 150'. I was in total disbelief and still don't know what went wrong.

A couple of other pilots said they would disable the on-off switch on theirs, thinking it was one more thing that could go wrong.
Another pilot said he would add a remote bec. Both good ideas.

I wrote to Horizon and am waiting to hear back. I'll probably have to buy another one, modify it per above and try it again, ouch to the wallet!

Horizon wrote back to me and asked me to return the plane to them for inspection. I shipped it back to them yesterday in a much smaller box than the one it arrived in.
I would imagine they will send me a replacement under warranty...I hope.
I will provide an update as soon as I know.

Luckily my elevator snap off on a landing and not during the air. I figured there would be more reinforcements in the tail section then a fiberglass strip. I enjoy flying the plane but I don't think its as rugged as advertised, oh well. Nothing glue and tooth picks can't fix. It's a whole cheaper practicing 3d on this then my giant scale stuff so I will keep it around.

Originally Posted by Full Spool

Luckily my elevator snap off on a landing and not during the air. I figured there would be more reinforcements in the tail section then a fiberglass strip. I enjoy flying the plane but I don't think its as rugged as advertised, oh well. Nothing glue and tooth picks can't fix. It's a whole cheaper practicing 3d on this then my giant scale stuff so I will keep it around.

Mine had a little hanger rash in the same area...I filled the rest of the gap where the spar is in with 5 min Epoxy. On both sides!

Well had two hard landings this weekend....

For the second time in two days, I split my Yak in the usual spot. Yesterday it was the 2' high water main in the pic below that got me on a landing. Today it was a hard landing (three point I think) that snapped it mostly a 1/4" away from yesterday's crack. So this time I'm going to add a little CFRP to the repair job.

There will be a short .25" dia CF tube run along the middle spar in the fuse (see pic). This should add support in all direction from pretty much the middle of the airframe. The longer spar will be run along the bottom as pictured from the landing gear/hatch door plate all the way back to where the tail becomes one piece (just past the seam line back there). The spar is a .0125" x.125" and is going to be epoxied in after the fuse is epoxied back together. This is a very thin spar, but since it is oriented vertically, it should provide a fair amount of protection from the problems I've had with the breaking fuse. It will also provide some additional horizontal support as well since it will be tightly epoxied in between the foam. I may cut a couple more of those same size spars into the side of the fuse; but might run it with these spars and see how it holds up before adding more CFRP and epoxy and weight to the tail.

On a better note, the motor seemed to run well today and I have not seen any wear on the motor mount yet (it's only got five flights on it since I replaced it due to visual stress fractures).

Thanks for this post.

I came looking specifically to see if there was an RCGroups Thread on he CZ so I could post my problem.

My issue was almost exactly the same although, I have not crashed my model at all. I was taxiing back to the pits after a 5 minute flight on a 3000 mah pack when the elevator servo suddenly went to full up.

I could not get the servo to recenter, so I disconnected the pack and turned on and off the TX. It stayed in the full up and then after about 2 minutes suddenly recentered itself without any stick movement.

I replaced the rx with a new out of the box Spectrum AR7200 and a new CC esc and motor mount as the stock cracked while doing a prop-hang.

The issue repeated next flight. Clearly I need to replace the servo and extension but the model would have been lost if it happened in flight.

BTW our Australian retailer, who I believe to be VERY good (Modelflight) aid this is the first reported isue of this type.


Maybe I should replace every servo if it is a batch problem.
J

Originally Posted by RC-Wings

I wouldn't call it a crash, but mine was all squarrely on the elevator. I attributed it to the excessive wind. It was finally a nice day here, but windy!

But when I landed I noticed the elevator servo would not center it would go like half full up to half full down, then move around a little more after I stopped moving the sticks.

I looked online to buy a replacement and its like 36 bucks! Anyone know of a cheaper replacement? From reading this thread, it sounds like this particular servo may have some problems...

I know others have had motor mount failure, today mine broke in 4 places. no crash.
Be sure to check your plane each time you fly, I dont know if it broke in all four places at once or broke and cracked over time..
Really crappy mount IMO.
Doug

Yep Doug,

Mine was also cracked at all four ends and seperated. Never a crash or hard landing. I had not been checking the mount as I did not know it was a problem but it developed an out of balance characteristic at higher RPM and then failed on a hang.

The prop was/is balanced. I have now replaced the motor and esc to a scorpion and Castle with my own motor mount solution. It is as smooth as a sewing machine now. Maybe the BL 25 is not so well balanced. Mine has no machining marks on it to show that it was.

I also replaced my offending servo and I'm thinking about doing all so I have confidence when I fly at full rates.

Well, I really did think I was going nuts. 2 crashes. e-Flite insisted there was nothing wrong.

Well - NOT TRUE!

Byron from L.H. in Phoenix went to bat for me. e-Flite gave him the same song and dance. But he came through and got me a New Plane from Horizon! Thank you very little e-Flite!

Now the good stuff.

Bryon rebuilt my crashed plane. Move the elevator servo to the rudder (just in-case a malfunction).

Sure enough the the elevator servo randomly would lock up. He said by pressing on the rudder it would reingage.

WOW! I am not crazy! Chris the service tech from Horizon was very adamant, in declaring me at fault.

Bryon diagnosed the elevator as having a bad potentiometer.

To learn more about servos, check out this link "Intro to RC Servos":
http://www.horrorseek.com/home/hallo...s.html#RCServo

Well, a good ending to a bad experience (except for the $$$ i spent on misc. things for the Yak 54).

So, my conclusion. Great flying plane! Don't trust the servos!

(thanks, Bryon!)