turning a heli properly

[cdkoho]

hey mutt get lost already, everyone else is giving great input.

thanks

[cdkoho]

you are banned!!!!!!!! please leave

[Mercuriell]

Probably balance of aileron and rudder most important for co-ordinated 'zero-g' turns - I like to lead with the aileron then feed in rudder to keep on a no-slip arc and then have a choice of compensating for incipient height loss by either upping collective if going slowly or in FFF by feeding in a tiny amount of up elevator to increase the AOA of the rotor disc - bottom line - there's no RIGHT way so do whatever turns you on - whether it's a pancake flat skid or a full blown plank bank and yank

PS Trolls best ignored

[Hotwings]

Mutt, you need to chill out, no one here has done anything to cause your comments.

Yes, i've been banned by MR a number of times, and he always asks me to come back.

The forum here is most useful as you don't get a lot of 1 gallon wonders telling you what is great. I don't whine, bark, or growl, but you are wrong with your attitude, This is meant to be a friendly, respectful hint, C-ya Ron

[saltyzoo]

Don't feed the troll.


I would think leading with aileron would probably be best in all cases, but how much rudder and how much aileron you use depends on the type of turn you want to make. Usually the rudder is used just to keep the heli pointed in the right direction in regards to the direction the heli is moving, which is usually determined by the bank.

[ClayK]

He's been banned.

[OverTemp]

I find they behave just like planks, at least my IMAC planks. Makes sense... they are both 3D ships. If you want to turn tighter, you roll in more bank, pull more elevator, and add more power. If you don't have enough power for the bank, the heli will lose its momentum and, instead of stalling like an airplane, float around and do strange things. Any turn is an acceleration, just like the merry-go-round throws you to the outside. Since F=ma, a = F/m. The more the heli weighs, the more force is needed to propel it around a turn without losing forward speed. Nothing is free.

I was flying today and I started some turns with very little bank. Nice lazy turns. I slowly increased bank, power, and elevator until I was at full elevator and about 75 degrees of bank. Note that at 75 degrees of bank, requires about 4 Gs of force to maintain altitude (G = 1/(Cosine of Bank Angle)). It took a good fist-full of power, and it was turning inside a couple feet... pretty cool!!!!! This was with a TRex 500 with high cyclic rates.

It's true, with "scale" 15 degree bank turns, you might not need MUCH elevator (but I doubt you are using zero... I bet you are using it without realizing... or you are skidding). You should ALWAYS need some sort of elevator. If you don't, you are skidding around the turn. 15 degrees of bank requires only 1.03G, so you won't even need extra power... effective transitional lift will take care of this.

If you slip around a shallow turn you might not need elevator. If you bank left, the heli will try to slide to the left. So now you add rudder to point the nose where the heli is slipping. The problem is that the heli will always be slipping toward earth.

If you skid around turns, you wind up needing to keep using aileron around the entire turn. Guess what... using aileron in a skidding turn is the SAME as using elevator. Visualize this... if you use aileron while skidding to the outside of a turn, it lifts the upwind side of the disk... this really is elevator.

In a proper turn, you should set the bank and then never touch the aileron again. You should use ONLY elevator and collective. If you DID have to use aileron, then your rudder control was off.

This is easier in rate mode, but I always fly in HH and coordinate my rudder appropriately. Still perfecting it for inverted flight.

[TomRex]

Ya gotta fly the tail too man! Only one more function along with constant altitude(collective) for your thumbs to think about huh?

[Dr. Memory]

Originally Posted by GunnyGlow

Is that directed at me??

You need to chill out. Thats so far out of left field I don't even know where or why you got all butt hurt.

No, it was directed at me.

And I'm at a total loss to understand why.

It's the internet. A person can make an enemy for posting the word "and". At least I know to avoid the fellow.

[Dr. Memory]

Originally Posted by OverTemp

In a proper turn, you should set the bank and then never touch the aileron again. You should use ONLY elevator and collective. If you DID have to use aileron, then your rudder control was off.

That's how it works in fixed wing aircraft.

Also, you pointed out the aerodynamics of it (which I elided above): if you don't use any elevator but simply roll the heli with aileron and kick the tail (yaw) around with the rudder, you will now be pointing down in a dive.

Think about it, guys.

Of course, as you say, in a very shallow turn you can get away with this. I routinely didn't bother with much if any elevator when I was flying (Cessna's) and did shallow turns. Steeper banking always required elevator, though, or you were very quickly in a spiral dive.

One maneuver that is part of pilot instruction and the flight test is called an "accelerated stall". It is invoked by putting the plane in a 45 degree coordinated turn, then pulling back on the elevator gradually so as to maintain altitude and instead lose airspeed due to the increasing angle of attack from the elevator input. Because of relative wind differences between the outer and inner wing, the outer wing stalls first --somewhat violently -- and snaps over abruptly. At that point, the stalled wing isn't flying.

Learning to recover from this is critically important. It is very easy to end up in a stall-spin, with the airplane spiraling down to the earth and ineffective control aileron and elevator due to air flowing in opposite directions over the two wings. You recover by maxing the throttle and kicking out with the rudder. Early aircraft designs could get locked in this condition with no control response at all from any controls -- far too many people died from stall spins. Modern aircraft generally don't have this problem, and can easily recover from a spin.

Anyway, I'm curious about this situation with a heli. While it is possible to stall a blade (isn't it?), I don't see any comparable situation. Is it possible to do an accelerated stall with a heli?

[Skiddz]

Helis fly differently than fixed wing. In fixed wing, you roll into the desire bank angle and then remove the roll input (i.e. center the yoke). The airplane will pretty much stay at that bank angle until you provide an opposite roll input to level the wings.

A heli requires you hold the cyclic over to maintain your bank angle. If you return the cyclic to center after establishing the bank, the heli will roll back to "level".

As for an "accelerated stall" it's not the same in the heli. The spinning rotor provides relative wind across the blades regardless of the flight attitude or speed. You *CAN* get moving too fast in forward flight and stall the retreating blade, but that's usually a result of the relative wind being too slow to maintain lift. You can also over-pitch the heli, which increases drag significantly and drags the RPM down, resulting in slow relative wind and both blades stalling.

[Vinger]

Originally Posted by Skiddz

Helis fly differently than fixed wing. In fixed wing, you roll into the desire bank angle and then remove the roll input (i.e. center the yoke). The airplane will pretty much stay at that bank angle until you provide an opposite roll input to level the wings.

A heli requires you hold the cyclic over to maintain your bank angle. If you return the cyclic to center after establishing the bank, the heli will roll back to "level".

As for an "accelerated stall" it's not the same in the heli. The spinning rotor provides relative wind across the blades regardless of the flight attitude or speed. You *CAN* get moving too fast in forward flight and stall the retreating blade, but that's usually a result of the relative wind being too slow to maintain lift. You can also over-pitch the heli, which increases drag significantly and drags the RPM down, resulting in slow relative wind and both blades stalling.

Heli returning to level flight without cyclic input????? Never ever, unless you have an electronic stabilizer of some kind.....

Helis actually fly very similar to planks, except the way the "wing" creates it's lift. Simplistically seen, the rotor system of a heli and a fixed wing aircraft's wingsystem can be seen as the same. Basic aerodynamics. The way we fly them in forward flight is basically the same.

[Dr. Memory]

Originally Posted by Skiddz

Helis fly differently than fixed wing. In fixed wing, you roll into the desire bank angle and then remove the roll input (i.e. center the yoke). The airplane will pretty much stay at that bank angle until you provide an opposite roll input to level the wings.

A heli requires you hold the cyclic over to maintain your bank angle. If you return the cyclic to center after establishing the bank, the heli will roll back to "level".

Mine doesn't. Nor does my sim.

Not challenging your much more extensive experience... Just stating my own. Further, if I don't give any rudder, elevator or collective, it will start to "slide" downward a bit along the angled rotor disc.

Maybe I have a setup problem?

[Dr. Memory]

Originally Posted by Vinger

Heli returning to level flight without cyclic input????? Never ever, unless you have an electronic stabilizer of some kind.....

Helis actually fly very similar to planks, except the way the "wing" creates it's lift.

Noob question: Is "plank" our (meaning heli pilots) term for fixed-wing aircraft? Or is it something exotic that I am unfamiliar with?

[TheBum]

Originally Posted by dwallersv

Noob question: Is "plank" our (meaning heli pilots) term for fixed-wing aircraft? Or is it something exotic that I am unfamiliar with?

Nope, nothing exotic, just fixed-wing.

I think a little cyclic needs to be maintained to counter the fact that the center of gravity is below the main rotor. I suspect the centripetal force of the turn would have an effect too. If the center of gravity was coincident with the rotor plane, you might be able to get away with no cyclic adjustments.

[Dr. Memory]

Originally Posted by TheBum

Nope, nothing exotic, just fixed-wing.

I think a little cyclic needs to be maintained to counter the fact that the center of gravity is below the main rotor. I suspect the centripetal force of the turn would have an effect too. If the center of gravity was coincident with the rotor plane, you might be able to get away with no cyclic adjustments.

I see what you're saying. Keep in mind that planks with high wing mounting (Cessna 152, for example) are in the same boat, although the moment arm is not as large as in a heli.

Planks will naturally turn when rolled due to the net vector sum of the lifting and gravitational forces. If you work out the physics, there is a centripedal force toward the center of the circle the craft is describing that is always perpendicular to gravity and normal to the aircraft long axis. This makes it turn when rolled off of zero degrees, whether rudder is used or not, and makes it turn with no constant aileron input.

Haven't sketched it out for a heli on paper, so I don't know if the same dynamics apply. It's certainly more complicated by the fact that the lifiting surfaces are moving relative to the long axis of the craft. My intuition, though, says to me that it should be very similar.

An interesting maneuver that must be learned in fixed wing aircraft is to deliberately produce a slip rather than a turn. This is done by applying opposite rudder to the roll direction from the aileron, causing the aircraft to "slide" diagonally sideways through the air instead of turning. This is essential for landing in a crosswind.

Helis do seem strikingly different in this regard... Any rudder input rotates the entire craft, opposite rudder turns the bird into a backward/sideways slip (at least on my sim), which makes physical/aerodynamic sense.

[Pinecone]

Originally Posted by dwallersv

That's how it works in fixed wing aircraft.

Also, you pointed out the aerodynamics of it (which I elided above): if you don't use any elevator but simply roll the heli with aileron and kick the tail (yaw) around with the rudder, you will now be pointing down in a dive.

Think about it, guys.

Of course, as you say, in a very shallow turn you can get away with this. I routinely didn't bother with much if any elevator when I was flying (Cessna's) and did shallow turns. Steeper banking always required elevator, though, or you were very quickly in a spiral dive.

One maneuver that is part of pilot instruction and the flight test is called an "accelerated stall". It is invoked by putting the plane in a 45 degree coordinated turn, then pulling back on the elevator gradually so as to maintain altitude and instead lose airspeed due to the increasing angle of attack from the elevator input. Because of relative wind differences between the outer and inner wing, the outer wing stalls first --somewhat violently -- and snaps over abruptly. At that point, the stalled wing isn't flying.

Learning to recover from this is critically important. It is very easy to end up in a stall-spin, with the airplane spiraling down to the earth and ineffective control aileron and elevator due to air flowing in opposite directions over the two wings. You recover by maxing the throttle and kicking out with the rudder. Early aircraft designs could get locked in this condition with no control response at all from any controls -- far too many people died from stall spins. Modern aircraft generally don't have this problem, and can easily recover from a spin.

Anyway, I'm curious about this situation with a heli. While it is possible to stall a blade (isn't it?), I don't see any comparable situation. Is it possible to do an accelerated stall with a heli?

That is NOT how aircraft fly.

1) In a helicopter, if you roll and use rudder to maintain coordinatedly flight, the nose doesn't fall. The helo does decend if you don't pull pitch as you have inclined the lift vector.

2) In an accelerated stall BOTH wings stall at the same time, unless you are not properly coordinated. If the outer wing stalls first, you are holding top rudder (anti turn direction) to "keep the nose up." And that is not a big deal as the aircraft rolls wings level while you are panicing. As long as there is no yaw, the aircraft will stall symetrically.

3) The outer wing would never stall first due to air speed differential. A) wings stall due to AOA NOT speed. B) The outer wing is flying FASTER than the inner wing. In gliders, with their long wings, the airspeed difference is very pronounced, and what you get is an over banking tendancy. If you roll into a 45 - 60 degree left bank in a glider, you will have to hold RIGHT aileron to prevent the glider from increasing the bank due to airspeed difference between the wings.

4) Name me one certificated aircraft that becomes " locked in a spin?" Every aircraft placarded against spins are fine for at leat 1 turn spin.

[keith shaw]

It's a radio controlled aircraft which requires a certain amount of eye/hand coordination. You see and respond accordingly. It takes some practice, but in time you'll feel out whatever it takes to get the end result you are looking for in your particular flying style. If you fly in HH mode, then it will certainly make you a better pilot with regards to flying the tail as you have to actually make a correction to the tail positon as opposed to having it streamline as in normal mode.

[Dr. Memory]

Originally Posted by Pinecone

That is NOT how aircraft fly.

2) In an accelerated stall BOTH wings stall at the same time, unless you are not properly coordinated. If the outer wing stalls first, you are holding top rudder (anti turn direction) to "keep the nose up." And that is not a big deal as the aircraft rolls wings level while you are panicing. As long as there is no yaw, the aircraft will stall symetrically.

Terry, I'm a private pilot (not current). I've done more accelerated stalls than I can count. What I described is precisely what a Cessna 152 and 172 does when you perform an accelerated stall. I very well may have recalled the aerodynamics imprecisely, as I was going from memory, and I got my pilot's license 20 years ago. I'll go back and review my books from flight training.

However, in an accelerated stall the outer wing stalls first, snapping the aircraft over, and it is very disorienting. Nothing like a straight on forward flight stall, which is relatively gentle, and simple to recover from. Like I said man, I've done it many times.

As for unrecoverable spins, I thought I was pretty clear that that was a problem with early aircraft. If I wasn't, my bad.

[kevntri]

I lead with the rudder and follow up with ailerons