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General control line discussion => Open Forum => Topic started by: frank williams on March 15, 2022, 08:30:31 AM
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The guy holding the plane in the first picture below is Mark Troutman from Katy Tx. He, an accomplished stunt flyer, egged on by his RC buddy George, will try anything in the way of experimental aerodynamics. Never a dull moment with the combined aeronautical genius these two posses.
I started to post this under Stunt Design, where there is a thread about flaps, but I figured that their ignominy should be more widely disseminated.
The photos show, after close inspection, that they have mounted two electrics motors onto the flaps of a stuntship. That’s right, mounted to the flaps. Who would have thought. Vectored thrust! Oh the Humanity. There is no motor up front, too banal.
Well, it got off the ground and flew. Mark said if flew like a really heavy Ringmaster. I’m amazed.
But, when you think about it, with electrics it is possible to actually easily hinge the powerplant. Have they opened a new dimension in stunt? Stay tuned.
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Genius at work. Errrr.... play.
The comment about flying like a Ringmaster could be edited to ' flies like most Ringmasters' .
I would imagine that motors on the elevator would create some excitement.
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Can't wait for the naysayers to say nay. I agree that vectored thrust may possess some benefit. I think the current rules would require it to be bellcrank driven though, which this one is.
Ken
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Mark does not need any help. I have seen him fly and he can do wonders with a lousy plane. Give him a good plane and he is tough to beat.
Are those two motors driven from the same battery that powers the main motor in the nose?
Someone will try to swivel mount the nose motor and see how that thrust vectoring works out.
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Very neat to see someone try something different.
ed
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Reread the post. There is no motor in the nose. y1 y1 y1
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Reread the post. There is no motor in the nose. y1 y1 y1
You are correct. I thought there was one in the nose as well, the prop being hidden behind his jacket.
Interesting experiment.
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Too cool.
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So when you pull up, the motors tilt down and push the plane up from behind the CG? Or does the elevator trump all
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So when you pull up, the motors tilt down and push the plane up from behind the CG? Or does the elevator trump all
I was wondering the same thing.
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Off the top of my aged head it sounds to me that the "system" involved is doing its best to maximize the adverse pitching moment of the deflecting flaps with respect to the desired pitch change thus requiring extra stab elevator input to get the danged thing "pitching" in the desired direction...perhaps even with the nose of the ship tracing a larger "loop" than the tail end! (Hmmm. that sentence might have set a Ted record for length!) Much like seeking tighter corners by making the flaps larger and more powerful when deflected so the "increased lift" thus generated would result in tighter corners without stalling.
So far, the concept sounds significantly flawed and the "Heavy Ringmaster" description of the resulting "stunt ship" not a huge surprise.
Ted
p.s. after proofreading the above I suspect it might sound a little "snarky" to some. If so, I apologize. Just trying to make a "witty" contribution. Our late great friend Bob Gialdini had a smart commentary on the aero aspect decades ago when he wrote (approximately) in a foundational construction article on his Olympic that if you want "rule book sharp" rather than "pretty smooth" corners make the flaps smaller. I expect, were he with us now and noting those high powered thrust generators on the trailing edge of the flaps...doing their best to help the flaps "pitch" the stunter in the opposite direction about the center of lift desired...he might well have "tut-tutted" a bit!
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Looks like to me the flaps should go same way elevator is going to go who needs lift if vectored thrust is going to push wing around corner.?
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I talked with Mark about it. He just laughed. He says it's going nowhere.
I told him I thought they might be more effective on the elevator. He says probably but the logistics of doing that would be a nightmare.
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Am I the only one seeing the props are backwards? I mean it is a pusher, right?
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Am I the only one seeing the props are backwards?
Yes
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He's running it with 6" props that are really rev'ing. Sounded GREAT! He is also using an RC car transmitter, so he has throttle control. Lots of fun things going on here.
From talking with him about it, a canard setup or just moving the main engine would be the real experiment.
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So, were the props flipped?
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So, were the props flipped?
Thank you, these props are 100% on backwards.
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Thank you, these props are 100% on backwards.
No, they are flipped which is the right direction with the motor facing rearward. Everybody wins!
Ken
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I'm with Dwayne on this one. In general, the leading edge of the prop faces the direction of travel for maximum efficiency, regardless if the powerplant is configured in front of or behind the prop. A quick google search shows many examples of this. Here is a link and a photo to a pretty good reference.
https://www.dronetrest.com/t/pusher-style-build-inverted-motors/6816 (https://www.dronetrest.com/t/pusher-style-build-inverted-motors/6816)
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Just reading the new stuff around flaps. Tom _Fluker mentioned the use of a cannard.
Has anyone tried this in CL?
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I'm with Dwayne on this one. In general, the leading edge of the prop faces the direction of travel for maximum efficiency, regardless if the powerplant is configured in front of or behind the prop. A quick google search shows many examples of this. Here is a link and a photo to a pretty good reference.
https://www.dronetrest.com/t/pusher-style-build-inverted-motors/6816 (https://www.dronetrest.com/t/pusher-style-build-inverted-motors/6816)
And the upwind side of a propeller is more convex than the downwind side. Curiously, windmill blades are backwards: the upwind side is pretty flat or even concave.
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Just reading the new stuff around flaps. Tom _Fluker mentioned the use of a cannard.
Has anyone tried this in CL?
Yes. Robby Hunt thinks they can be made competitive in stunt.
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Howard,
A little correction, modern power windmill blades are flat on the downwind side (even the Dutch windmills are curved on the windward side) and curved facing the wind, the pitch for maximum power is almost flat maybe 2 deg positive. The airfoil used is somewhat like a half polliwog. The airfoil curvature creates the airflow that slides down the face and creates the turning torque. Neat the hub on the larger 2.5 MW machines there is a row of vortex fins that help reduce drag.
Best, DennisT
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NEWS FLASH ..... They added a canard to the powered flap experiment ..... It turned better ... was stable ... and was considered a success
Under the heading of stable .... it should be noted that the normal sized "rear: stab and elevator .... in the effect of the twin motors' blast,.....the tail plane really looks HUGE ..... the extra qbar (dynamic pressure) from the props is really quite an effect to be reckoned with. .... I suspect that that the cg could be moved way aft ..... but ...save that for later ..... it flew better than "a heavy Ringmaster"
Another thing that grabbed my attention was the "high revving" low pitched props and the steadiness of the flight velocity, for an overweight plane. At the Lubbock Nats, I was into that sort of thing .... launched at 13K ... it worked, but could be heard a mile away and rivaled jet speed in the circle next to us.
***if some could recommend a good video editor that doesn't need a 12yr old kid to make it work .... I will post some videos of the flights*** video probably needs compression also .... can't meet the SH size limits *****
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Fascinating. Frank - does the canard move in concert with the flaps? ie when flaps are down , so are they?
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Thats correct ... same direction of rotation as the flaps
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Frank! Awesome stuff as always!
You can post the video to youtube then put a link here.
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A couple of videos .... with and without canard ..... both with "powered flaps"
https://vimeo.com/691216648
https://vimeo.com/691137501
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And now for something completely different....
Wow, the pattern doesn't even come close to taxing that thing's capabilities - Ken
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Bout all I can think of is very cool...
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Frank- Fascinating stuff.
Q - what if you fixed the flaps? elevator and full moving canard only? Just wondering?
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What motors and props are being used?