E-flite Carbon-Z Yak 54 * CRASH SITE * Report Your Crash - Page 2 - RC Groups
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Mar 03, 2011, 05:36 PM
Never fly an A model anything!
jayb1rdz's Avatar
Thank you for starting the thread Byron. I replaced my elevator servo and will do all before the next flight with Imo Lab digital MG s.

Pity you/we were inadvertantly recruited as a beta test pilots.

The motor mount and or BL-25 motor balancing remains an issue. I swapped those out too. All in all a very expensive piece of foam when the replacement of these components is not optional for safe operation. J
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Mar 03, 2011, 07:51 PM
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Originally Posted by jayb1rdz
Thank you for starting the thread Byron. J
Just for clarification. Byron was my local hobby shop owner that went to bat for me, when both e-Flite, Horizon local sale rep. and Horizon corporation refused to do ANY thing.

I am the one that started the thread, and I am just an end user like you guys.

I am glad to see people communicating. Maybe the manufactures will start paying more attention to us.
Mar 03, 2011, 09:30 PM
Never fly an A model anything!
jayb1rdz's Avatar
If you are cool with this, I will send the link to ModelFlight The distributors here in Australia. I think they are really decent and would want to know if there was product had issues.

Ciao J
Mar 06, 2011, 11:38 PM
certified crash instructor
Another report of elevator servo failure here. I was on my approach for landing when I banked at about 45' high and then lost elevator, went nose first into the ground. Still can't believe this happened, it just wouldn't pull up and or around, really had no control, just had to watch it plow into the ground. The elevator servo seems jammed, it takes a bit of force to even get it to move. I am sending it back to HH for inspection, the only thing that's left intact is the rudder, Rx, a wing, half the elevator, landing gear and charger, the rest is damaged, even the the motor, esc and lipo. Only 5 flights and this thing was in perfect condition, not a scratch, until this happened. I really was enjoying this plane too, hopefully HH will help, if not I just spent $400 for 20 minutes of fun.
Mar 07, 2011, 02:41 AM
Registered User
rcpilot23's Avatar
Originally Posted by jayb1rdz
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.
Im in Perth and Modelflight have already replaced the mount and the motor in my CZ YAk 54 after like 10 flights.

I have had no servo problems so far.

Done about 10 flights with the new motor mount and motor.

I haven't pushed my Yak very hard yet.

Are the servos failing even when flying mild?
Mar 07, 2011, 04:06 AM
Never fly an A model anything!
jayb1rdz's Avatar
I was lucky.... Mine failed after landing. Mine is still in mint condition, not a ding or scratch. My elevator servo just locked in the fully up position after landing. More than once but only once after a flight. I don't know if it has something to do with low voltage as I did notice a correlation to well used batteries but it was strange that it was only my elevator servo. J
Mar 07, 2011, 09:57 AM
Registered User
rcpilot23's Avatar
So why is the elevator servo failing?

Is it under too much stress?

Are the other servos in the plane ok?

I want to fly mine today but not game now after ready this thread
Mar 07, 2011, 04:34 PM
Never fly an A model anything!
jayb1rdz's Avatar
It seems some of the servos had faulty potentiometers.

It's hard to maintain confidence when there appears to be no clue as to why they fail. As I said my only correlation was I observed the faults at or near LVC levels although nothing improved when I switched my ESC to a castle.

I suppose there are many hundreds sold and flying well and it is just those that experience faults that seek forums like this. If mine did not have the issue observable on the ground between flights, I probably would have assumed RX or pilot issues and not gone looking for this thread.

Mar 07, 2011, 06:55 PM

So I'm not alone.

I had a servo failure today on the Carbon Z. I was lucky as it happened when I plugged up the battery and turned on the switch. The right aileron when full down on its own, five seconds passed, then it went full up on its own, and stuck right there. In flight, this would have been a $300 failure as it has been for many. I'll report this to Horizon but I'm also replacing the servo while that argument goes on. I've actually had good experiences with HH. We'll see. I'll never be comfortable flying this plane again, regardless. Only two flights...
Mar 08, 2011, 06:35 AM
Registered User
hi l have had the same fault on my ailron servo to and crashed the carbon z and l emailed horizon but they told me to ring O'Reilly Model Products-Distributor but they were no help at all so l emailed horizon and they told me to

(The only other option would be to send the plane to us for replacement I
am sorry that they will not help you out. If you would like to send it
here for a evaluation you are more than welcome to but could cost as
much as the plane its self.)
l would not trust another carbon z again
Mar 08, 2011, 07:10 AM
Registered User
WOW glade I came across this thread. (no crash for me yet)

I have one from Model Flight in Adelaide.
Mine has only had x1 5min test flight.
The test pilot was very very gentle with it and touched down like a feather.

Now do I risk flying it without changing over the servo's ?

This is my first plane after a 10 year break. (never used digital servo's before)
I actually rang the store when I put it together because the elevator servo was making so much noise... cherping morse code..
They told me it was normal.

I now know they all do it a bit.
But the elevator one is so loud that when setting up the throw's and dual rates.
Because of the anoying noise; I just wanted to put the plane in the oven and kill it !
Mar 08, 2011, 11:54 AM
Registered User
cbr998's Avatar

elevator servos

I notice that on Hobby Kings 58.5" foam Yak 54 they use two elevator servos could this be a rare case of HK actually being ahead of the curve here?

Has HH or E-Flite had any official comment on the servo failure issue?
Mar 08, 2011, 06:17 PM
certified crash instructor
Originally Posted by rcpilot23
Im in Perth and Modelflight have already replaced the mount and the motor in my CZ YAk 54 after like 10 flights.

I have had no servo problems so far.

Done about 10 flights with the new motor mount and motor.

I haven't pushed my Yak very hard yet.

Are the servos failing even when flying mild?
I was flying mild, I was actually on my turnaround for the landing approach when this happened, at about 50' or so I banked to the left, hit the elevator and I got a slight reaction for a split second, plane started turning and then nothing, I held the elevator full back as I just watched it nose dive into the ground with no control. I will have to send it back to HH, not sure how much that will cost, not sure if they will replace it either. Even if they do replace it, I probably won't fly it untill I get a new Rx with remote and flight logging just so I can feel a bit more comfortable. I learned a hard lesson already, I should have had this stuff on a plane this expensive but then again I wouldn't expect a failure on it's 6th flight, it had maybe 20 minutes of flight time, not a scratch on it. I also want to upgrade my DX6i to a DX8 and get a new elevator servo. This has been a horrible experience so far, not only that 30 people saw what happened and the plane crashed about 20' away from a group of bystanders. We'll see if HH steps up to the plate on this one, I was looking forward to an enjoyable experience with this plane, still can't wait to fly it again but can't really afford it, especially if HH doesn't help me. That will be around $500 ($400 plus tax and shipping it back to them) down the drain for 20 minutes of fun.
Mar 10, 2011, 09:56 AM
Registered User

Set up questions

As a recent purchaser of this Carbon-Z Yak-54, I found these threads extremely interesting. The question I have to the gents who had elevator- or aileron-servo failure is in two-parts:
The manual has specific set ups as to where the pushrods are attached to the control horns and for measuring the control throws. Were these followed? I'm sure they were, but I'm just wondering.
The manual also says that if you are flying the Yak at high speeds, then the low rates should be used. Were these servo failures the result of ripping around and then suddenly pulling hard on the elevator stick or rolling when the controls were on high rate? Again, just wondering.

I look forward to your replies.
Mar 10, 2011, 05:19 PM
Never fly an A model anything!
jayb1rdz's Avatar
Good questions and I will re-check my throws when I get back to OZ. I have to say that mine did not fail in flight but - lucky for me after landing.

I purchased my model PNP so it was pre-built with rods etc. I checked all throws and set the TX as recommended before flight. I have been flying mine aerobatic as opposed to 3d so I have never put mine on full high rates yet.

The only correlation I have found with regard my servo malfunction is that I landed and checked my battery levels. Out of a 3000mah 4s pack I had according to my PL-8 charger only 4% fuel left. Elevator servo went full up before removing the pack.

In hindsight I was foolish and flew again with new packs and had no problems as I was convinced that after checking everything it may have been a poor servo connection fixed during the pre-flight check over. Still no crash.

Later when checking the model at home, and checking prop balance, I plugged in a well drained pack.... 8% fuel remaining..... elevator servo malfunctioned full up. I replaced it.

I still have the offending servo, the model is near immaculate, no dings at all. Normally I would just throw an untrusted component but kept this in case the manufacturer wishes to examine.

I'm not loooking for replacement or compensation. I just want to make sure I do not damage person or property with my models, so I am happy to help where I can. J

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