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Dual aileron servos

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Old 05-06-2008, 02:38 PM
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spiral_72
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Default Dual aileron servos

Well the title might be a little misleading, however:

I run dual aileron servos on my Advance 40, semi-symetrical wing because I can. I set it up for flaps because I could. Dropped the flaps in flight and it made no difference in flight. Over time I introduced more and more flap now with about 30 degrees down flap it has started to float on landing just like it was supposed too (not that it needs it mind you)

That being said, maybe apples to oranges, I aquired a Hanger 9 Pizazz, full symetrical wing with huge-by-big ailerons. Same dual ailerons, but this time I set it up for 30 degrees down flaps and 30 degrees up flaps (I don't know if you call "up flaps" flaps, but excuse the ignorance) to just play with on my three position switch. In flight dropping the flaps really doesn't do anything but drop the nose and the up-flaps really don't do anything but raise the nose. If I use elevator to correct the attitude, the plane just flies happily away with a little less lift it seems.

I have a delta wing also and I understand the principle of elevons and how they work, but delta wings don't have tail surfaces like the above planes do..... So what's going on here?

I guess what I'm asking is why doesn't flaps(erons) slow the plane and produce more lift? and up-flaps make the plane drop like a brick?
Is this a flat bottom airfoil trait only? or is it that the flaps/spoilers are the full length of the wing? Or something else?

I guess I expected something exciting to happen. If anything changed in flight it was very subtle.
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Old 05-06-2008, 03:57 PM
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Default RE: Dual aileron servos

Using down flaps in limited amounts increases both lift and drag with both flat bottom and symetrical airfoils. However, you are probably carrying a lot more power than you need to appreciate the change in performance. Typically a low wing plane will pitch down with the application of flaps so if you saw the pitching moment occur you could have taken advantage of the situation by reducing power to slow down or by increasing the nose down pitch to descend at a steeper angle at a relatively slow speed. The Pizzaz has such a high lift airfoil that the addition of flaps likely doesn't make a difference. Use of "up" flaps will permit tighter loops though.
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Old 05-06-2008, 08:02 PM
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Default RE: Dual aileron servos

Both ailerons up are called spoilers or spoilerons. This will let you descend at a steeper angle and not float on landing. Normally, I set a flaperon wing type, then mix throttle-master and flaps-slave. I set the flaperons to go up at idle about an inch to start with. As you advance throttle, the spoilers (up flaps) drop down and are normally back to the regular aileron position at half throttle. This is handy for touch and goes and for adding power to fly the plane closer to yourself on landing. I use this set-up on all my sport and 3D planes.

You can set flaperons coupled to elevator two ways. Flaps opposite to elevator will increase lift and give you tighter maneuvers. Flaps the same direction as the elevator can be useful in a harrier to keep the nose up and also for flips. Set them up where full down elevator gives you 30 degrees or more down flap. Fly by at half power and pop up vertical, then go full down and full power. The plane will normally flip around in a tight, outside "loop" or something. The plane just rotates around. You will need at least 45 degrees of elevator travel. More if you can get it. The Twist is good at this, so the Pizazz should be, too.
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Old 05-06-2008, 10:27 PM
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Default RE: Dual aileron servos

The first post pretty much describes what i have found in my own experiments.

I've tried 40% down flaperons on a Magic and a Tango. On both models i was expecting the model to balloon with the application of the flaps but it was actually the opposite. The nose drops rapidly.

With some up elevator as compensation the model can maintain altitude at slower speeds and really improved the glide times in a fun fly event.

Like Ed, i also have a mix that deploys the spoilerons as i move the throttle from half down to idle. I was planning to test this mix on the weekend to see if it helped with short landings in the carrier landing task (ie, use the spoilerons as airbrakes) but engine troubles took all my concentration. I will give it a go this coming saturday.
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Old 05-06-2008, 11:18 PM
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Default RE: Dual aileron servos

What they said. Also, both flaps and spoilers are most noticable at slow speeds. You have to drop/bleed off speed and then deploy them. At higher speeds the drag offsets the lift of flaps and can do squirrely things to your flight. If you go nose up you can mix in some down elevator (even on a slight delay with radios like the 9C). I have had models that don't show much effect and others that are very noticable. Most flat bottomed airfoils (IMHO) would do better with spoilers to add some drag and settle the model at a steeper glide path IF the pilot has the discipline to bring it in slow to begin with.

You can have lots of fun with four aileron servos and split ailerons and "CROW" the surfaces. Outer ailerons up and inner ailerons down. Can be a programatic nightmare until you get the radio figured out (This I know). I was about bleeding from the ears by the time I got this programmed into my Hot Stik. Interesting, but really not value added for that model.

Another fun one is the Contender 60 that has a huge apron flap with 1-1/2" throw that you tie to the landing gear switch (It has fixed gear and is pretty much a warbird trainer). Gets you used to slowing down and tripping the switch before landing, Without that it comes in pretty slippery. With it it comes in steeper.
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Old 05-07-2008, 01:12 AM
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Default RE: Dual aileron servos

Careful with that 3 position switch.

I inadvertently left the ailerons in the "up" or spoileron position on takeoff.

The plane got up to speed, but just wouldn't take off. As I neared the end of the runway, I throttled down, only to find that it finally lifted off no longer under power. At this point I thought it was a faulty/broken elevator pushrod so I didn't throttle up. After a couple of frantic stalls, the plane settled into some young soy plants. Luckily, damage was minimal, but now I always check the flaperon/aileron switch before takeoff.

Spoileron position seems to allow the plane to sink without picking up much speed. Flaperons allow me to slow down more while flaring just before touchdown. I haven't played with the throw, however.
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Old 05-07-2008, 09:20 AM
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Default RE: Dual aileron servos


ORIGINAL: patternwannabee

Careful with that 3 position switch.

I inadvertently left the ailerons in the "up" or spoileron position on takeoff.
YES! I have did the same thing. However I caught it. At some point while I learned to fly, I picked up the annoying habit of sitting on the runway with the engine idle and check all my throws and look for reversed servos, etc. Good thing too. I figure it has saved me two planes so far. Kinda annoying for everyone else though I suppose.

Ed_Moorman
Yea, the Pizzaz is very similar to the Twist and the Tribute. I'll have to try that maneuver and play with some others. I'd especailly be interested to see of flaps flatten my flat spins any.

I'll play with it some more. I knew what the two flap positions were "supposed" to do, but it wasn't very noticable. It's nice to have it confirmed though.
Maybe I AM overpowering the flaps with throttle.

I was scared to call up flaps, spoilers because they are typically hinged plates on top of the wing. Wasn't sure if I could get away with the term.


Well all this was pretty much the Pizzaz's maiden flight since I am the new owner. I gotta figure out a couple things, like why the rudder rolls the nose, and some other oddities.

Thanks for the info! Ya' been a big help as always.
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