Electric Stunt > New electronic technology
Electronic bellcrank idea?
fielding mellish:
Tim, I didn't see your comments as negative. I was just considering the idea as a thought experiment. The fly-by-wire concept is intriguing, but I doubt I'll ever try it.
Tim Wescott:
--- Quote from: Howard Rush on May 04, 2015, 02:28:44 PM ---It's something a controls engineer could do, but I would hope it's outlawed for stunt contests and that anybody who tries it is banished to RC.
--- End quote ---
Aw c'mon Howard. What if you wanted to do a semi-scale stunt version of an X-29? How could you possibly build it with the CG in front of the neutral point?
Dwayne:
--- Quote from: fielding mellish on May 04, 2015, 06:20:29 AM ---Guys,
I'm curious about a variation on the electronic bellcrank concept. Instead of handle movement commanding a certain elevator position, what if handle movement commanded (proportionately) a certain pitch RATE? When the handle is neutralized, the model would maintain its current pitch attitude until another correction is received. Would this be possible or practical, and would it make for smoother flying?
--- End quote ---
Not sure but isn't this the same as Kim's fly by wire setup a few post's down?
Tim Wescott:
--- Quote from: Dwayne Donnelly on July 10, 2015, 07:11:26 PM ---Not sure but isn't this the same as Kim's fly by wire setup a few post's down?
--- End quote ---
If I'm not mistaken about Kim's system, it basically has the elevator and flaps following the bellcrank, possibly with something like exponential rate tossed into one or the other surface -- but it always presents a 1:1 mapping of bellcrank position to elevator and flap position.
What Fielding is talking about (if I'm not mistaken), is a system that servos the rate of rotation of the plane to the bellcrank position -- meaning that there would have to be a controller in there that senses the rotation rate and moves the elevator until the plane is moving as fast as it is commanded. It would be a very different system (and probably impossible to fly at slow speeds if you did it exactly as stated).
Paul Walker:
If you have a good stunt plane and know how to trim it better than I do, you can do this aerodynamically with traditional control linkage. I flew an Impact once (not mine) that looked like a poor simulation of a stunt plane. The engine made the same sound everywhere, the airplane went the same speed everywhere, and I saw only the profile of the plane: never any wing, never any oscillation. A handle input resulted in a pitch rate proportional to input. It was weird.
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I believe there is only one person (other than Howard) who knows what you are describing.
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