hey everyone,
So most of you know my Leader crashed today and I have no idea what caused it, nor does Simon or anyone else at TEMAC today. Simon was doing buddy box with me and we made sure all the controls on both remotes were trimmed properly, the control surfaces moved correctly and yes we did make sure the CG was fine, and it was. We taxied onto the field and took off, the second we got in the air, the plane went straight up. Simon tried to level it out but the elevators were not responding so Simon leveled out the plane with the controls he had, he managed to keep it leveled for a few seconds and just when he called for a emergency landing, the plane shot up again, stalled, nose dived and hit the ground from about 100-150ft high. The elevators worked perfectly on the ground but did not respond in the air and the plane kept shooting upwards. Keep in mind this was not the first flight with the Leader, I flew it perfectly fine last Wednesday with Mike. One think I took into consideration when trying to find out what happened was that the battery had no velcro on it, it was held on just by 1 strap around it. The battery was tightly strapped in and Simon approved it (not blaming it on you Simon). Is it possible the battery fell to the back of the plane causing it to become extremely tail heavy? Simon also tried using the slave remote to control the plane and it didn't work. I just want to know what could have caused it so I can prevent it from happening again.
Thanks
Big thanks to Simon for trying his best to save me plane!
I don't think that the battery can shift back far enough on a leader for that to happen.
Was this model using as3x? If so was it properly calibrated before flight? Did you do a range check?
Sometimes weird things happen. You'll never really know why.
It sucks, but crashing is part of the experience.
No, I didn't have AS3X. we didn't do a range check but when we lost control it was still over the runway.
And by the way, they still had control of other surfaces, just not elevator. Well as far as I'm aware of.
whether we had elevators or not, the plane should have flown leveled because the CG was fine but it kept shooting upwards.
Hmm could have been a glitching servo. Or a linkage let go.
i tested it once we retrieved it. it was fine.
ouch sorry to hear about your crash... fix it up and give it another go (crashed planes always fly better)
The battery didn't move - it was still in the position we put it in, after the crash. So I don't think it was a CG issue.
As Imran said, literaly as soon as we took off, with very little elevator input, it went vertical and then I couldn't adjust the pitch at all. Not even sure how I managed to level out.......it was very weird. I did have throttle and aileron control though. I tried to swap to the slave controller, to see if the elevator control worked on that TX, but it pitched up again and we lost it and spun in.
We flew Imran's plane immediately after, another Leader, and it was perfectly fine. No issues.
As Imran said, we checked all trim and throws on the ground. My thoughts go to AS3x - I wonder if it could have been counter-acting my inputs? Or trying to "correct" my flight somehow?
I take 3 lessons from this episode (personal lessons, up to you if you agree/disagree):
1) Always range check
2) Don't use AS3X for training
3) Train with a foam plane - easier to repair! ;)
Don't worry Imran, we'll get your Leader back in the air. :)
I believe there is a calibration point on AS3X that when you put in the pack the receiver must be in a specific position relative to the horizon.
You might have been fighting the "stabilization"
The AS3X was off and i check a few times to confrim that it was off before flight, also I didn't set it up, the guys at the hobby store did so even if it was on it would have worked properly and not have done this.
I agree, ALWAYS do a range check and I don't know about anyone else but I am never wearing a neck strap when training incase the trainer requires the slave remote quicky.
We didn't lose signal, I still had throttle and aileron control. But a range check is good habit.
Simon did you have rudder control?
I wasn't using Rudder.
okay, i just wanted to know because the elevator and rudder servos are from my brothers extra 260. maybe when he crashed something happened to the servos or servo.
It happened fast..
I suspect that something might have gotten binded somewhere are the plane pitched up. I would check the servo a few times. I think that simon H had an issue where the collar to the elevator slipped (not sure if the leader is the same with two rods to the elevator?
Also do a pressure test on the elevator and servo and see if it skips a tooth. Sometimes you bang the elev and that breaks the servo. I usually depending on the model put a metal one in rudder and elevator for this issue.
* Please fix the plane* its not that bad!
I wasn't at the field so this is pretty much a shot in the dark ...are we sure the bottom motor mounts and standoffs were tight?
Hi Imran,
Many mysteries go unsolved - especially with electronics. For example, there could have been a bad connection in the servo which only appeared with the vibration in flight. or it could have been in the receiver. You may never find it.
I am sure you will repair the plane and you may want to re-use as many components as possible but if the cause was not obvious then the safe thing to do is not re-use anything in the elevator control path which can't be absolutely verified to be good.
I had a similar experience last Wednesday with my Apprentice. When I flew to the South East corner of the field and started to turn right my elevator locked down causing the plane to go up and eventually loop. It did it a few times but it was intermittent. When I brought the plane in the elevator servo was fine. I did have a capacitor plugged into my Rx that came lose so it may have caused binding with elevator linkage. If it does it the next time out I will consider replacing the servo.
Thought:
I have had a problem once where a servo output arm skipped a position on the toothed output wheel that comes through the servo case. This happens when there is a sudden input on a loaded surface (up elevator) and/or the servo arm is not 100% correct for the servo. When this happens it is the equivalent of adding double max. up trim and it will never centre properly again. When you test the servo, everything looks and acts fine.
Apparently the plane is on its way to my house as we speak.. for repairs. Simon just called.
Will check it out and report back.
Frank
Here's what happened.
None of the above.
I have started rebuilding the model. This model has two aileron servos, one in each wing with a direct link to the aileron pushrod.
Noticed last night that the left wing had the servo arm facing forward (in line with the pushrod). On both left and right aileron input the aileron would only go up. That meant that on a left turn, the ailerons were working properly (left aileron up, right aileron down). When a right aileron input was given, both ailerons would go up, acting as an elevator (elevon), sending the plane skyward.
The servo arm should be span-wise and 90 degrees to the pushrod. The servo horn screw was still in and there were no stripped gears.
It will fly again. ;D
The new wing tube just arrived.
Frank
I believe this plane flew fine previously. My thinking is that the AS3X was initialized incorrectly causing it to "think" that level flight was very nose high.
Re-build update:
Picked up the new wing tube at GreatHobbies today (Sunday). The wings are back together and the fuse is re-built. The screw-in wing lugs are in place and aligned. Am letting them dry overnight then I will take everything apart and re-enforce the entire structure*
Should be ready this weekend. ;D
Frank
* I rebuild the entire structure first so it will hold together and be straight. I then go around all joints and re-enforce them with plywood, balsa or fibreglass. This way excess glue and wood does not get in the way of joints and pieces that need to come apart.
Imran, looks like instead of a "flimsy" ARF you will end up with a custom built Semi composite plane built by an expert. I am sure you didn't think about this when you first got it. ;D ;D
How much weight do all these repairs and reinforcements add?
re: How much weight do all these repairs and reinforcements add?
About the weight of a piece of bubble gum. Will not affect flight performance. You will not notice it. Guaranteed. ;D
Frank
I KNEW that was your secret repair technique. Works for leaky drain pipes too ;D
Finished! The plane is done and Simon picked it up this evening. On its way back to you.
Regards,
Frank
Thank you Frank. Another truly remarkable repair.