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HomeAircraftHelicopterCentury Radikal G20-30 N640 Hawk Predator › Looped through the ground AGAIN!
03-30-2005 12:58 AM  13 years agoPost 21
Darksyde

rrApprentice

Chur, Switzerland.

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You are correct wisdom seeker, you do need to feather the collective while applying aft elevator in a loop(if you expect to make the loop a perfect circle that is). I think Jack was meaning, don't apply too much cyclic when your collective is already maxed out. Which gets back to my earlier post about keeping some pitch in reserve for your cyclic commands to access. If a heli begins to bogg down in a climb out at 11 degrees of pitch doesn't mean that you should run 11 degrees of pitch. You should back it off to 10 degrees or just over 10, leaving the remaining pitch for your cyclic commands. If you are running 10 degrees of pitch in collective and then a further 5 or 6 degrees for cyclic, your blades will for sure stall if you crank the cyclic stick while at full positive collective pitch.

Karl.

Go Bling or Go Home!!!!

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03-30-2005 01:22 AM  13 years agoPost 22
RICH.L

rrKey Veteran

gentry arkansas

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does that logic about the cyclic and pitch relate to all engines or just the smaller ones?
i bought the hiper 50 for my raven,could i still be in the same situation?
old fart had a good post about cyclic mixing,unfortunately my rd 6000 super can't do that.
i remember my first loop was more like a flip,i was in fff and about 100 feet or better of the ground and i started my loop but wanted the heli upright as soon as possible.
it just hung up there for a moment and then flipped,never lost any head speed but sure scared the crap out of me///
rich

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03-30-2005 02:00 AM  13 years agoPost 23
Darksyde

rrApprentice

Chur, Switzerland.

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That logic applies to any universe that is ruled by the laws of physics, regardless of engine choice. Its a simple matter of blade pitch vs. power input and the result is head speed.

Too much power and not enough pitch will cause too much rpm.

Too much blade pitch and not enough engine power will cause blade stall and too low of rpm.

Imagine that you are pushing a car along a road and then you encounter a hill along the way, you will get to a certain grade that you will no longer be able to push the car by yourself. Now you need more people to help you push. In the case of your heli blades the engine is you and the blades are the hill, the steeper the hill the more friends(horsepower) you need to get the car up the hill.

The aim is to adjust the power input and blade pitch at each point along the collective/throttle range to achieve a consistant head speed(assuming you are looking at a 3d curve that is). In the case of a normal curve the previous statement only holds true from hover to full throttle, but from hover to low stick in a normal curve there should be an rpm decay down to idle.

Karl.

Go Bling or Go Home!!!!

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03-30-2005 05:01 AM  13 years agoPost 24
BC Don

rrElite Veteran

Calgary, AB Canada

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Thanks for the replies.

I do in fact have a set of glass blades sitting the box. BUT, my reasoning for continuing to use the woodies is 2-fold. First, I 'should' be able to loop OK with the woodies and second, the cost.

The Governor isn't for the Hawk it's for my Raven and in any case, its not to help in loops, I know that it won't magically make the engine able to rev higher.

My plank flying has taught me that a good flyer can fly the snot out of planes that a beginner has trouble with. For example, I have an underpowered trainer, I can make low inverted passes along the field and do most aerobatic maneuvers (not 3D) except knife edge (just not enough rudder). However, it is more difficult to do a nice reverse cuban 8 on a high wing, high dihedral underpowered trainer than on a pattern plane.

Ergo, I should be able to maneuver the Hawk around into basic loops, rolls, 540 stall turns, inverted hovering, autos, flips and piros. Mabe even a death spiral if I start high enough.

I agree, it is set up. But exactly what is to be determined. It may be that I have too much cyclic available (I don't have any dual rates dialed in). But we'll see once I get things back together again.

Got Money? Send it to me, I'm a Heli Addict.

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03-30-2005 05:19 AM  13 years agoPost 25
jackheli

rrProfessor

Vancouver - Canada

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As you apply collective you proportionally take out cyclic and vice-versa. It is the balance between the two inputs that you have to keep in mind.

At the top of the loop you only need something like -3 to -5 to keep the heli going, while you can ease off on the cyclic to the same amount so you don't flip over or make an "egg-shaped" loop.

I think BC Don's problem is on the decent, when he sees the ground coming fast so he applies positive collective and jams aft cyclic at the same time.

Wooden blades won't take that.

It's easy to find an excuse to do wrong. Hard is not to find an excuse to do right.

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HomeAircraftHelicopterCentury Radikal G20-30 N640 Hawk Predator › Looped through the ground AGAIN!
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