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And a video of Michael's model ...
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And a video of Michael's model ... -
Got in 14 flights this afternoon. Light winds. Was VERY much watching for anything weird and primed to react if I did see something odd. Nothing....
What a riddle!!!
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So all these crashes and still no answers as to why, Motion has got to be pulling their hair out on this one, I don't hang out here much on the Mig posts because I will never own one but I do jump in once in awhile to see the latest news and seen the last video of another one going in, so all the ones that have crashed and I'm curious, is MRC replacing all these kits that have been lost?? I don't think I seen a post yet where anyone got a replacement sent to them or did I miss that??? It has got to be a weird feeling to be flying along and all of a sudden, down she goes.
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Anybody have an higher frequency oscilloscope they can put on the power wires connecting to the ESCs? I'd love to look at how clean that signal is coming from the ESC with and without the chokes. As folks have mentioned, RF chokes and ferrite rings will suppress high-frequency noise coming down those lines. The higher the frequency, the more they will suppress the high frequency noise generally. Any harmonics that show up as a multiple of 2.4 GHz can affect our radios. That means if you get a 1.2 GHz, 4.8 GHz, or 600 MHz it may affect our radios (although it's far less likely). This is basic electrical engineering (yes I'm a EE) and it's very common practice in high frequency electrical circuits to install these chokes or to install a capacitor between power and ground to suppress noise. It's also common to not run a potentially noisy, high power line down the same wire bundle or circuit path as a small signal line because of the possibility of transmitting noise through magnetic inductance.
It's also possible that a lower frequency, but high power signal in the KHz range is bleeding from the power wires into the signal or power wires feeding the servos. If the battery power leads are running parallel to any other wires they can magnetically transmit the noise from them to parallel wires - like the ones running our servos. Servos run off pulse width modulation in the 50 Hz range (which is very low frequency) so their signal is unaffected by the ferrite rings. I'd be curious what would happen if that signal got "noisy". If you really want to do "belt and suspenders" protection, it may also help to not run any servo or signal wires along with the battery power leads. The closer the wire, the more interference can be transferred.
I have all of two flights on this thing, but I had the Cedmon Ferrite Rings you can buy from Amazon in place and all was fine. I'll be doing some more cable management now before I do more flying, just to be double sure.Comment
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The crash just mentioned was with a Futaba. And the TX has some kind of modification to it's antennae, see 1:10. Something is odd with his RF link.
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Did some frame by frame of this latest crash. Do those stabs not look like full up deflection??? The shading does not match the flat wings. What to think now????
I just wish he would have chopped throttle before impact so we could have seen how it reacted and possibly recovered. Full bore to the ground though. The first thing I do after any of my planes acts or sounds weird is kill throttle immediately. Saved my old nitro powered P-51 multiple times back in the day when the rudder hinges broke and the tail fluttered. Always during a high speed dive, strafing run.. Go figure. ;-)
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SHARP EYE!! What’s up with that transmitter modification ER.....attempted repair?Originally posted by Evan D View Post
RCMustang (EE)....care to comment? 1:10 in the video of post #2090
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I don't believe the pilot who is the subject of the video is here.Originally posted by GliderGuy View PostComment
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The video is too vague to make an educated guess. It looks like an older Futaba transmitter and it does not look like a stock antenna, but that may not mean anything. I had an old JR9303 that had an Xtremelink RF module and my antenna was removed because the RF transmission was actually attached to the RF module on the back of it. I think only the model owner can comment on that.
If the antenna is doctored, it can affect the transmitter gain which means a weaker signal makes it to the receiver meaning it's more susceptible to RF noise.Comment
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Good points - I made a hasty and possibly unwarranted comment. Thanks for the push back to reality. Need more info from the owner.
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That is the same radio I have been using for the last 10 yrs, it's a Futaba 7C, mine has flown 30-40 EDF jets and 14 scale helis plus giant scale gas powered planes, I have swapped many receivers from plane to plane to heli, but anyway that radio is one of the best ones made, it has a great reputation as well, but that antenna looks different than mine, Futaba put the longer antenna on the older versions, then a shorter antenna on the last version of this radio which is out of production now, something just doesn't look right, but then again, other Migs have crashed using different equipment as well, his jet looked to be flying fine at first like in some of the other videos, strange that's for sure.Comment
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Noticed something else in the video. The flaps were still deployed here at 4:01 just before the final high speed pass attempt. The picture is from the video at 4:01. The flaps are still deployed during inspection of the wreckage. Would this not cause severe blanking of the horizontal stabs during a dive this steep and fast with flaps deployed? I will test this theory the next time I fly but I will be way up there.....
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I think you're onto something here. This was after his second slow pass, and at least half flaps were definitely deployed after that pass and then the falling leaf maneuver. You can see them down still after all that. Hard to say whether or not he put them up, but I'm wiling to bet that he forgot to put them back up before the high speed pass attempt. Regarding the position of them after the crash, I would say that the impact on the nose would force them down. Looked like they were deflected as far as they would go, and he definitely didn't have that much flap in on those two slow passes. Either that, or he accidentally flipped the flap switch the wrong way. Who's to say for sure what happened.Originally posted by HaroldAnderson View PostNoticed something else in the video. The flaps were still deployed here at 4:01 just before the final high speed pass attempt. The picture is from the video at 4:01. The flaps are still deployed during inspection of the wreckage. Would this not cause severe blanking of the horizontal stabs during a dive this steep and fast with flaps deployed? I will test this theory the next time I fly but I will be way up there.....
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I thought about that but the ailerons are not drooping down from the crash and both flaps are down the exact same amount. I know the flaps are hinged differently though. I used to forget to pull flaps up all the time and finally programmed my radio to tell me that my flaps were deployed if the throttle is above 60%. Before that I've made many high speed pass attempts and wondered why it seemed slow.... Hey, I'm getting old... He was talking to the camera man too. I've found I don't fly nearly as well and forget things when I'm talking during flying. I feel really bad for him but I'm just trying to figure out this mystery.Originally posted by crxmanpat View Post
Maybe someone will try out the challenge before I get the chance. LOTS OF ALTITUDE, full throttle, flaps down, pitch down to 45 degrees for a second or two and see if you maintain elevator control. Did I mention lots of altitude!!Comment
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I think you are on to something, he stated he would do a high speed pass as he entered that turn. You can here it go to full throttle as it was exiting the turn and starting the downhill run.
Would be interesting to see if there are some high speed aerodynamics going on that will blank out the stabs if the flaps are deployed.Comment
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flying at high speed with flaps is a bad idea.Comment
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I found another video by RC Plane Reviewer (the guy who later crashed in the video that started this discussion). The guy with the “odd Futaba antenna”.
He has a series of 4 MiG videos #4 is the crash.
Notice at the beginning he states he experienced FULL LOSS OF ELEVATOR CONTROL.
Then he proceeds to fly the MiG making the statement about NOT KNOWING WHAT CAUSED the loss of control.
Basically, he flew to see WAZZUP with this plane. He found out in his next video. DOAH!
It seems that he continued flying with an undiagnosed system bug. In a prior video of his, he has a 5000 in the front bay and made a statement, “The CG is good.” His crash video he recanted that statement and moved the battery to the middle bay.
I think we can safely toss this crash aside in regard to future posts. Comments?
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No i don't think that is a fair comment at all. Whilst many of us would have done things very differently after the first problem, the crash remains very relevant regardless of battery position etc.Originally posted by GliderGuy View PostI found another video by RC Plane Reviewer (the guy who later crashed in the video that started this discussion). The guy with the “odd Futaba antenna”.
He has a series of 4 MiG videos #4 is the crash.
Notice at the beginning he states he experienced FULL LOSS OF ELEVATOR CONTROL.
Then he proceeds to fly the MiG making the statement about NOT KNOWING WHAT CAUSED the loss of control.
Basically, he flew to see WAZZUP with this plane. He found out in his next video. DOAH!
It seems that he continued flying with an undiagnosed system bug. In a prior video of his, he has a 5000 in the front bay and made a statement, “The CG is good.” His crash video he recanted that statement and moved the battery to the middle bay.
I think we can safely toss this crash aside in regard to future posts. Comments?
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Need to know more about the back story on the transmitter antenna...which we won’t. The potential of a weak RF link cannot be discounted. May not be the plane at all in this one instance.
More scrutiny of this crash is needed in regard to other possible causes. In this case...not possible to accomplish.
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