Well there's your problem right there!!! :P Really, that just sucks.... The gear trains are OK in the servos? I have never seen that happen in over 35 years of this great hobby... Let me know what you find please!!! Wow...
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Yeah, easy to see why it rolled right now for sure. But, like you, I am truly lost on what in the world happened to cause it. I sent the pictures and video to Motion last night. I didn't want to touch anything before hearing back from them though. When I hear something, I'll dig in deeper but right now I am clueless. I sat on the couch staring at this thing until 1 AM last night trying to figure out how it goes from perfectly even to this on its own. :Thinking::Confused:Originally posted by Hardway View PostComment
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Wow! I can't even imagine what would cause that. I hope the matter gets resolved for you!My YouTube RC videos:
https://www.youtube.com/@toddbredaComment
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Almost sounds like a servo has something wrong with it.Originally posted by Aros.MotionRC View PostComment
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A good study of the F-22 here in this video. Lotta nice shots of the aircraft. I mute the electronic narrative for increased enjoyment. Cheers !!
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My guess is it's a bad potentiometer(inside the servo). Had this happen in a Topflight Corsair 35 years ago. Rolled right, I corrected, then it rolled right again and went in.:Scared:Originally posted by Aros.MotionRC View PostComment
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[QUOTE=JamesonC;n177481]
Well, here is some follow up to my maiden crash. After buying a new servo tester and letting enough time go by to try to start investigating what happened, last night I pulled it out and started. Did not take but a minute to see something was way off. While going through the "sweep" function, it was obvious the elevators weren't in sync. The first time, I tried it after the blue box, the second time, I did them before the blue box and got the same result. When centering them with the tester, they were also off from one another. I scratched my head staring at it for 10 minutes and then decided to plug in a lipo and see what it did with the tx on. The picture below is what it now looks like with the elevators at neutral on the tx. Let me say, I set this plane up exactly per the manual and we all know how much conversation there was about the elevator neutral point so I spent a bit of time making sure both were right. Before the maiden, myself and another went over it a few more times checking throws and looking everything over. There is exactly a 0.0% chance this plane rolled down the runway away from me with the elevators looking like this. So, whatever caused this is why it rolled right twice shortly after takeoff. My question is what the heck happened. I am truly stumped!! :Thinking:
Possible scenario:
I have seen this have with a servo with a bad output shaft the drives the gear train. What happens is the shaft slips inside the gears, allowing the pot center to move. This is very rare but with the shaft slightly loose with the gears moving under load...… the servo center will move causing a very bad situation.
RichComment
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This is the best explanation I have seen so far for what happened. How would one explore that idea to see for sure?Originally posted by RichJ53 View Post
Motion is just wanting me to readjust them to level and try again which doesn't make a ton of sense when trying to figure out how the right one got like that. I am betting the control rod won't even have enough thread on it and I will have to re-clock the servo arm to get it back level with the left side. Once again, I don't really see what that is going to do to help figure this out but I will give it a shot I guess.Comment
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This is a Brand new aircraft and that certainly is helpful here. If the servo was slipping 'Internally' somehow, I'm sure there'd be some evidende of that. some wear mark, some pieces of material inside or some evidence on the gears of this slippage. It happened 'Under Load' admittedly, not much of a load, so I would check it under load and try to get it to Slip/Shift/etc... again !!Originally posted by JamesonC View Post
Dangerous business trying to diagnose this, cause your diagnostics themselves may damage the servo if done aggressively enough to determine the servo integrity. GL with your findings. Hopefully you can get to the bottom of this and maybe, best case, you get 'Comp'd' if a verifiable defect is detected !! GL Sir.Comment
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Believe I would buy a couple of new servos. They are not that expensive.Originally posted by Bobaroo View PostComment
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Well I would too. What about the rest of the crashed plane?Originally posted by adb2@suddenlink.net View PostComment
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Yeah, that's why I didn't want to go too far before getting in touch with MRC. Last thing I wanted to hear was that I somehow caused it by diagnosing.Originally posted by Bobaroo View PostComment
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Have a reason to have them replace it if rhat was the problem. At least it seemed to me.Originally posted by JamesonC View PostComment
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Again... this was just a possible cause. I have seen this issue in person. So, while everyone is brainstorming I wanted to share this possibility. it is very possible the servo had a hidden defect or the center moved due to the forces from the crash? really hard to sayOriginally posted by JamesonC View Post
I believe MRC customer service are a great bunch of fellows. Maybe just remove the servos from the elevators (marking them) and return them to MRC for evaluation. These servos are under $10.... just buy some new ones and make sure they test out okay and move on. Most RC Helicopter modelers have servos that cost more than $200 each...
All the best
RichComment
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Yup, this was only a possible cause or suggestion. Just trying to help.Originally posted by Bobaroo View Post
Should MRC have the customer return the jet for evaluation of the possible cause of failure? really opens up a can of worms
I saw this happen on my own 700 series helicopter on the swashplate with 90* CCPM setup. What happened is one of the servo's basically had a servo arm trying to move the swashplate but internally the output shaft turned inside the gear bundle (thusly changing the servo center) The shaft has a serrated spline that should lock the gears from moving un the shaft (but it stripped). It could be possible to spot some damage on the gear or shaft.
RichComment
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Could the servo arm simply have jumped splines? If the servo isn't stripped, checked the tightness of the screw holding the arm on the servo and then check the splines inside the servo arm. Just grasping for straws here...Comment
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Gonna dig in deeper in the morning and video it all. I'm determined to find the root cause.Comment
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