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Apr 16, 2021, 12:44 AM
CR5
CR5
Registered User
Quote:
Originally Posted by OhBee
Ailerons may have re-reversed on impact! I've seen crashes reverse servos before.
How is that even possible? They don't just reverse.

Quote:
Originally Posted by tic
He should have used a "SAFE" spektrum receiver. That technology saves a lot of planes from this sort of demise
No thanks. It also stops a lot of pilots from actually learning to fly correctly.
I never maiden with SAFE. Never.

Safe can not correct pilot error when the plane is that close to the ground.

SAFE can also make a bad situation worse, imagine a tip stall, the low wing has stalled, then SAFE applies aileron to try to level the wings but that low wing is already stalled and giving a down aileron correction on the low wing just makes the stall worse as it increases the angle of attack of the stalled wing.

I don't want anything getting in the way if I need to recover. Sometimes the only way to recover it to point the nose down to gather some speed and pull out. Having SAFE try to level the plane just extends the time it takes the motor to give the plane the speed it needs to fly again.

SAFE is not the safety net novice pilots (and some more experienced) think it is.
It can tame down a plane that is too advanced for the pilot but it doesn't know where the ground is and it doesn't know how much airspeed the plane has.
If you are flying with SAFE on and you go too slow coming around off the downwind leg on landing approach SAFE can not save you from a tip stall.

Crashing is part of the hobby, accept it or don't fly. Nothing can guarantee that your plane is coming back down in one piece.



The pilot said while walking towards the other guy that the ailerons were not reversed and that it just F'd up on him. Whatever that means.

It looked tail heavy but it's hard to be sure about anything from the video.
Too little airspeed with a little too much control throw got it out of shape and then he panicked a little and kept overcorrecting till it speared the Earth.

Just a guess though.
Last edited by CR5; Apr 16, 2021 at 12:55 AM.
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Apr 16, 2021, 04:34 AM
I like real wooden aeroplanes!
Sundancer's Avatar
If we accept that the postmortem established that the ailerons were not reversed then the only explanations for the left aileron which is clearly applied immediately after lift off are: 1. If one was present, reversed gyro, 2. radio problem - lack of range perhaps, 3 servo/linkage failure or 4 pilot error. After that things just escalated and, despite what has been said, I would take some convincing that a rearward CG and excess control throws were not contributory factors.
Apr 16, 2021, 05:00 AM
Beach Bum
SteveFlysloco's Avatar
For reference, this video shows some behavior with gyro reversed for ailerons.
I have flight experience and good reflexes, but no chance flying it.
Fail, gyro reversed (1 min 48 sec)
Apr 16, 2021, 08:58 AM
Registered User
Tlacuache's Avatar
Quote:
Originally Posted by SteveFlysloco
For reference, this video shows some behavior with gyro reversed for ailerons.
Thanks, interesting. I realize we are all speculating idly and don't really know, but since that is what forums are for.....to me this looks quite similar to the original video.
Apr 16, 2021, 09:04 AM
tic
tic
thunderscreech
tic's Avatar
Quote:
Originally Posted by CR5
How is that even possible? They don't just reverse.



No thanks. It also stops a lot of pilots from actually learning to fly correctly.
I never maiden with SAFE. Never.

Safe can not correct pilot error when the plane is that close to the ground.

SAFE can also make a bad situation worse, imagine a tip stall, the low wing has stalled, then SAFE applies aileron to try to level the wings but that low wing is already stalled and giving a down aileron correction on the low wing just makes the stall worse as it increases the angle of attack of the stalled wing.

I don't want anything getting in the way if I need to recover. Sometimes the only way to recover it to point the nose down to gather some speed and pull out. Having SAFE try to level the plane just extends the time it takes the motor to give the plane the speed it needs to fly again.

SAFE is not the safety net novice pilots (and some more experienced) think it is.
It can tame down a plane that is too advanced for the pilot but it doesn't know where the ground is and it doesn't know how much airspeed the plane has.
If you are flying with SAFE on and you go too slow coming around off the downwind leg on landing approach SAFE can not save you from a tip stall.

Crashing is part of the hobby, accept it or don't fly. Nothing can guarantee that your plane is coming back down in one piece.



The pilot said while walking towards the other guy that the ailerons were not reversed and that it just F'd up on him. Whatever that means.

It looked tail heavy but it's hard to be sure about anything from the video.
Too little airspeed with a little too much control throw got it out of shape and then he panicked a little and kept overcorrecting till it speared the Earth.

Just a guess though.
Thanks for posting.. Please see my thread "SAFE technology should be banned" and feel free to comment
Apr 16, 2021, 09:54 AM
treefinder
springer's Avatar
Coming in late to this discussion, but watching the vid a few times, and recalling many of my own flights, it looked much like torque reaction trying to roll the plane, and instead of compensating and continuing, he cut throttle, which is where he lost it. I fly only electric, scratchbuilt foamies, and don't use any preset side thrust, so takeoff with a fresh lipo often gives a rolling turn left when I apply power. To compensate I automatically add right rudder as I run up throttle. Once the plane leaves the ground I let off rudder and if needed (still rolling) straighten with ailerons. Gas probably has different power/thrust/reaction, but the lift off part of the take off looked a lot like some of mine, and the increasingly wild gyrations after, trying to control without overcontrolling also had a familiar look.
Apr 16, 2021, 10:38 AM
Registered User
koppterX's Avatar
with no right thrust on a foamie, the plane is light enough to feel the torque effect. not so which something this big. even with right thrust, it requires compensating rudder, but not putting it in results in the plane doing a ground loop, not lifting a wing.
Apr 16, 2021, 12:40 PM
Registered User
E-Challenged's Avatar
What does Judge Judy say?
Apr 16, 2021, 01:34 PM
CR5
CR5
Registered User
Quote:
Originally Posted by tic
Thanks for posting.. Please see my thread "SAFE technology should be banned" and feel free to comment
I did. Wasn't sure how serious that was though.
I wouldn't go so far as to say it should be banned. I just hate to see pilots depend on it like if it wasn't for SAFE there's no way they could fly the plane. If that's truly the case it's time for those guys to go back to a trainer and actually learn to fly.

SAFE is a useful tool when used correctly, but buying planes too advanced for the pilot's skill level and using SAFE to bridge the gap is not the way to become a proficient pilot. Same as I tell my buddy I'm trying to teach. He still can't fly his UMX Timber with any kind of control but he'll still take it up and shut off SAFE to do rolls and loops. Then he crashes and wonders why he keeps crashing.
Last edited by CR5; Apr 16, 2021 at 01:41 PM.
Apr 16, 2021, 02:37 PM
treefinder
springer's Avatar
Quote:
Originally Posted by koppterX
with no right thrust on a foamie, the plane is light enough to feel the torque effect. not so which something this big. even with right thrust, it requires compensating rudder, but not putting it in results in the plane doing a ground loop, not lifting a wing.

Your comment made me look up the details of ground loops, an interesting exercise as nearly every mention and video I found was regarding groundloop on landing. But I did find this in the wikipedia definition:
"In aviation, a ground loop is a rapid rotation of a fixed-wing aircraft in the horizontal plane (yawing) while on the ground. Aerodynamic forces may cause the advancing wing to rise, which may then cause the other wingtip to touch the ground. In severe cases (particularly if the ground surface is soft), the inside wing can dig in, causing the aircraft to swing violently or even cartwheel.[1]"

Note the "aerodynamic forces may cause the advancing wing to rise". This explanation, of course relative to full size, so I would expect to apply better to giant scale than small foamies. If he pulled up at the same time as torque reaction occured, the left wheel pivot may not have been strong enough to achieve the loop, but the wing up and his subsequent throttle chop set up for the next over control sequence, it seems.
Apr 16, 2021, 03:09 PM
I fly, therefore, I crash!!!
SteveT.'s Avatar
The North American AT-6 was a ground looping son of a gun, and it was purposely built that way to teach young pilots how to avoid and get out of them.

SteveT.
Latest blog entry: My shop....
Apr 16, 2021, 08:04 PM
DHG
DHG
Kinetic Sculptor
Quote:
Originally Posted by tic
He should have used a "SAFE" spektrum receiver. That technology saves a lot of planes from this sort of demise
Assuming you have it set up right. But if somebody can rig their ailerons backwards, they can certainly program their ailerons backwards ... I've seen it happen.
Apr 16, 2021, 08:16 PM
DHG
DHG
Kinetic Sculptor
Quote:
Originally Posted by Sundancer
If we accept that the postmortem established that the ailerons were not reversed then the only explanations for the left aileron which is clearly applied immediately after lift off are: 1. If one was present, reversed gyro, 2. radio problem - lack of range perhaps, 3 servo/linkage failure or 4 pilot error. After that things just escalated and, despite what has been said, I would take some convincing that a rearward CG and excess control throws were not contributory factors.
Well, don't forget it's a Citabria. I can't speak for how well they fly in full scale, but I've never seen a model Citabria that was worth a plugged nickel. I think this is the dirty little secret nobody wants to talk about ... the First Cause Uncaused, the All of the Above, the Alpha and the Omega. I certainly sympathize with the gentleman who owned it, but I suggest that after a socially acceptable period of mourning, he remarry and make better choices going forward.
Apr 17, 2021, 01:31 AM
Registered User
Citabria, fly beautifully full scale, I have many hours on them. i loved practicing side-slipping into a landing with no flaps. I could trust it it all the way. That maiden looked like tail heavy, torque roll and over correcting.
Apr 17, 2021, 09:11 AM
Registered User
koppterX's Avatar
It’s not a Citabria, it’s a Decathlon. And it wasn’t tail heavy. Nor was torque a factor. Just very poor piloting.
Last edited by koppterX; Apr 17, 2021 at 10:05 AM.


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