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Old Apr 30, 2014, 07:39 PM
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Does anyone use a lifting stabilizer on electric gliders?

Waaaay back when I built free flight models a lifting stab, basically a miniature version of the wing, was used to maintain a more level climb without the need to figure out the balance between powered climb and glide trim. Would not a lifting stab, properly set up, on a powered glider provide the same benefit?
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Old May 01, 2014, 12:27 AM
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Joined Feb 2014
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It should have that effect. However, if your radio supports mixing, you can just mix in some down elevator at high throttle settings. I have a 2 meter floater that I added an electric motor to, at full throttle it wants to go past vertical, so I set up a mix that adds down elevator but only at 80% throttle or more. Then it's just a matter of fiddling with how much elevator to mix in...
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Old May 01, 2014, 06:32 AM
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I use the elevator stick.
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Old May 01, 2014, 08:14 AM
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Joined Dec 2005
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....or use the correct amount of down-thrust on the motor mount.
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Old May 01, 2014, 09:07 AM
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Fond du Lac, WI
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More lift means more drag. A lifting stab is going to result in more drag which in turn is going to result in reduced penetration. So when you follow a thermal downwind it is going to be more difficult to return to the launch area.
Many years ago a famous designer of model airplanes designed a 2-meter sailplane that had a lifting stab. Myself and friend quickly purchased a kit and built one. When it was dead calm that sucker sure floated but we quickly discovered that with a wind speed much above 5 mph that it was nearly impossible to penetrate upwind.
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Old May 02, 2014, 08:27 PM
The Lone Sloper
USA, NY, Orchard Park
Joined Apr 2007
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Originally Posted by Al M View Post
I use the elevator stick.
YEH, Me too, too many mixes, too much to get screwed up. Thank You
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Old May 02, 2014, 10:25 PM
Ascended Master
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Palmdale, CA
Joined Oct 2000
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Free flights are essentially single speed airplanes, optimized to glide.
The motor just yanks them up to where the thermals might be.
Going upwind is just not something a free-flight does.
It drifts downwind while circling.
To get it going upwind, the elevator has to be used.
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Old May 02, 2014, 10:37 PM
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Quote:
Originally Posted by Al M View Post
I use the elevator stick.
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Originally Posted by zbytekfr View Post
YEH, Me too, too many mixes, too much to get screwed up. Thank You
Me three. Thumb to brain mixing works well for me.
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Old May 02, 2014, 11:04 PM
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Thanks, guys. That's pretty much what I guessed but I can still see where an old timer with only thumb mixing available, or a newcomer on a budget, might benefit from the particular type of stability offered by a lifting tail. This whole train of thought comes from a discussion with a guy I trained long ago on a Cox EZ-Bee.

It was foam, powered by the obligatory Baby Bee, and had a very high lift wing. I actually loved the way it flew and the only thing keeping it from being the Radian of its day was that damned Baby Bee and lack of a folding prop. One of its quirks was that one would need to hold more down as the engine leaned out towards the end of the tank and then actually add more down when the engine quit, and one lost the benefit of the down thrust, until the speed bled off. This all occurred when the plane was highest ad farthest and my friend couldn't quite master it. He would start into a porpoise mode just before the engine quit and, as often as not, would be ready for landing by the time the PIO was under control or he handed me the transmitter.

Eventually; I fabricated a lifting stab for him and it worked like a charm. Even with the weight I added to the tail, and partially because of it, it made the plane much less oversensitive in pitch without any real harm to its gliding performance. For a beginner trying to master flight with a powered glider I can see where some designs might be tamed down a bit.

BTW. I still have a full set of plans and the female portion of most ribs and formers for a 72" Buzzard Bombshell. The original, with an O.S. .19 and a pound of radio gear, was a great sailplane. If I ever feel like a real project I might just make one with modern materials and a electric power train (and maybe retractable gear?).
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Old May 03, 2014, 02:29 PM
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Originally Posted by peterlngh View Post
Eventually; I fabricated a lifting stab for him and it worked like a charm. Even with the weight I added to the tail, and partially because of it, it made the plane much less oversensitive in pitch without any real harm to its gliding performance. For a beginner trying to master flight with a powered glider I can see where some designs might be tamed down a bit.
Raising the LE of the stab would have had the same result the same but with less drag.
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