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Ultimate bipe turns during loops

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Old 12-06-2008, 06:17 PM
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Jeremyd
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Default Ultimate bipe turns during loops

My GP ultimate bipe Electric has a tendency to want to fall to the left while I am performing loops. What would cause this?
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Old 12-06-2008, 06:28 PM
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normgoyer
 
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Default RE: Ultimate bipe turns during loops

Hi, If it falls, rather than turns, the aircraft is stalling. Try entering the loop at a faster entry speed and reduce extra elevator and try for a nice round loop. Another cause is that you may need more power or a different prop. If it is turning at the top of a loop check motor/engine thrust settings. A stall at the top of a loop can end up in an inverted spin. Full size Texans loved to do this and scare the pants off the pilot. Norm
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Old 12-06-2008, 07:24 PM
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Default RE: Ultimate bipe turns during loops



My GP ultimate bipe Electric has a tendency to want to fall to the left while I am performing loops. What would cause this?

HI, IF IT IS TURNING AS OPPOSED TO FALLING, THEN THIS COULD BE DOWN TO THE AIRPLANE NOT HAVING LATERAL BALANCE.

FLY YOUR MODEL AWAY FROM YOU IN A STRAIGHT LINE AT REASONABLE THROTTLE AND PULL REPEATED LOOPS.... IF THE TENDANCY IS TO TRACK OFF LINE, THEN THE LATERAL BALANCE OF YOUR AIRPLANE COULD BE OUT. IT CAN BE RECTIFIED BY ADDING SMALL AMOUNTS OF WEIGHT TO THE OPPOSITE WING TIP.

JUST A THOUGHT
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Old 12-06-2008, 07:51 PM
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Jeremyd
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Default RE: Ultimate bipe turns during loops

I will try both, thanks for your quick response's.
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Old 12-10-2008, 04:44 AM
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Default RE: Ultimate bipe turns during loops

Lateral balance is a must.
But all planes have a tendency to track to the left when you enter a loop (If the propeller doesn`t rotate opposite of normal). Gyroscopic forces, and always occur. I always add a small amount of right rudder when I enter a loop, some planes require "some", other require nearly zero rudder input.

When the lateral balance is OK try some loops when flying straigt away from yourself, wings level. If it still go left try to add a small amount of rudder trim to the right. Then trim level flight on ailerons. This trim might help a lot.
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Old 12-13-2008, 09:01 PM
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Default RE: Ultimate bipe turns during loops

Doing a loop with to much throw will make most planes snap out of a loop. If you make the loops bigger and it doesn't roll out, back off the elevator throw just to the point before it snaps out.
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Old 01-26-2009, 01:10 AM
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Default RE: Ultimate bipe turns during loops

All of the above and check thrust line too.Be patient its usually a combination of several things.
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Old 01-27-2009, 03:37 PM
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Default RE: Ultimate bipe turns during loops

Ultimates, by nature are definately a bird of a different color. I'm on my third .46 sized Ultimate and know many who own larger and smaller ones. The plane, because of being a bipe, is quite draggy, in the air. Add to this that the rear stab and elevator is close coupled (close to the trailing edge of the wing) gives it some unwanted tendencies.
First off, people tend to build them a little nose heavy. While this isn't all bad, it does tend to make one fly the plane faster than normal. Remember that the CG is set on the top wing, while inverted.
Ultimates are great aerobatic planes. However, they are not real good at 3D. They will do all sorts of aerobatic manuevers, but trying to fly them in a semi-stall like a 3D plane is flirting with diaster. They will snap roll so fast, that you'll be looking at a debris field, before you even have time to react. They require powered flight at all times. Trying to glide then around slowly will cause a stall, every time. This goes for landing, also. You need to fly the plane to the ground, power on. Flying close to the ground and then cutting the throttle, while giving up elevator, like a Cub, will make you an expert at plane repairs.
When you talk about rolling out at the top of the loop, I know what you're talking about. Mine will do it every time, if I'm running reduced throttle and trying to loop too tightly. Ultimates don't seem to care how much aileron or rudder throw you dial in, however elevator throw is an entirely different matter. My first one, was set up by the book. After checking all the throws, I determined that the elevator throws were way to small. Having flown numerous 3D and aerobatic planes, the elevator seemed like it would need twice as much as the book called for. I decided that that would be good for low rates and set it up for almost double that for high rates. On the maiden flight I used low rates until I got it trimmed out. All was pretty good. I landed, installed a fresh pack, and decided to see what it could do....I took off and imediately switch to high rates.....I got to the end of the field and banked left to come around, and gave it a slight amount of up elevator. It, immediately snapped and I bearly caught it before it met the ground. Shook up I decided to land and check it over....About this time, an experienced Ultimate flyer showed up at the field and had witnessed the event. He came over while I was checking it over. After watching he told me I should cut the elevator back to stock for high and 50% of stock for low rates. I readjusted it that way and took off. It was amazing. The 3/8 inch throws were substantantial enough for almost all flying....Switching to high rates (half of what I originally set it up for) the plane got a little twitchy....but it was still controllable. I tried a couple loops and every time it would roll out at the top....The experienced Ultimate flyer suggested I give it full throttle and try it again. At full throttle it only had a hint of roll out....I landed the plane, after that....He came over and suggested I dial back the elevator on high rates 10%....I did this on my next flight and was very happy with the results. The plane flew beautifully. The only issue was that it was flying a little faster than I'd have liked....However, every time I tried to slow it down, it got squirrely....I'm told this is normal for Ultimates and Pitts bipes.....
I said it was my third.......because I destroyed the first two....The first was a aileron servo arm failure...I learned to ditch the standard servo arms in favor of HD ones. The second one I crashed twice on landing. The first time I lined up and brougt in nice and low.....All was perfect.....Until the inner moron took over the controls. instead of flying it to the ground and then backing off the throttle, I backed off the throttle while ther plane was in the air, and then tried to use elevator to slow the descent.....This is a NO-NO....Five feet from the ground, it snap rolled and when nose in.....This took me 6 hours to repair.....The very next time at the field, I basically made the exact same mistake, and this time there wasn't enough left to repair.
My current Ultimate has 20 flights on it. I always make sure that I'm not fatigued, when flying it. Every manuever is though out before performing it. (including landings) When I start feeling very confident, and start doing some wilder stuff, it's time to put it away, and dig out my Erratix, or Funtana.....I luv the way the Ultimate looks and it flys like it's on rails.....But, before I decide to get wild and crazy with it, I'll need a lot of flights on it. I've gotten more confident with it and the principles required to fly it are the same for all planes. The difference is that many are a lot more forgiving than an Ultimate. Learning to fly an Ultimate will make you a much better pilot, if you can get past the early frustrations.....Pat
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