No adverse yaw?

[Boch]

, but I'd bet if you are doing vertical rolls, you are good enough to counteract it instinctively...

lets be clear, a vertical roll is a 1G move, but it is also 0 Lift angle manuver.

I think it may be the only way in an airplane to have 0 lift angle while still having 1G.

 

[Headwind]

Bosh that makes sense.

 

[jafo20]

edit

The amount of yaw you feel (rudder required) depends on a lot of things. The downard deflected aileron will always* generate more induced drag (adverse yaw), but this can be offset by the proverse yaw on the descending wing.

*You can actually stall your deflected aileron under certain, very specific conditions. If that happens you may feel a lot more or a lot less adverse yaw based on how it stalls. You may also feel lightening or hard-over on the stick. It's pretty hard to do this.

So, loaded or unloaded, the downardly deflected aileron will generate some adverse yaw. The opposite, downwardly moving wingtip will also generate a little more lift and little more yaw. So what you sense varies on a number of factors.

Some of these variables are average angle of attack on entry, types ailerons, how far outboard the airlerons are, maximum roll rate, wingspan, etc.

Your original understanding of adverse yaw is correct.

Your aerobatic instructor was correct for describing little to no sensed adverse yaw while the plane was unloaded.

All the technical stuff falls away as you simply do what you need to to do make the airplane do what you want.

It's actually kinda cool to see how different airplanes perform and feel through the same maneuver.

Tangent:
Did you have fun?

 

[d.fitz]

lets be clear, a vertical roll is a 1G move

??? How's that? The typical "1-G" description is 1-G measured parallel to the vertical axis. Like a 1-G roll while holding a glass of water....

and you are correct that you are on the zero lift line when vertical (if done perfectly), but you are not generating zero lift when you deflect the ailerons...

 

[Boch]

what is the "vertical axis" realitive to exactly?

1g is 1 x the earths gravity. go up, down, sideways what ever just as long as you are not changing your vector you will have 1g. velocty + change in vector = G
you generate lift when you deflect the ailerons this is always true, but as I said before the lift you do get is negated by the equal* and opposite lift you get from the other wing.

as for you jafo, you sir speek the truth. I was trying to keep it comprenendible for a mear mortal man. you must be some kind of aerobatic highlander. I commend you, just dont try to chop my head off.

 

[VxClimb]

deletedhttp://www.funnyforumpics.com/page.php?image=/forums/WTF/1/wtf-animated.gif&name=wtf-animatedgif

 

[VNugget]

what is the "vertical axis" realitive to exactly?

The airplane.

1g is 1 x the earths gravity. go up, down, sideways what ever just as long as you are not changing your vector you will have 1g. velocty + change in vector = G

What you're talking about is the total acceleration summed up on all axes on the plane, which is best represented by a coordinate system fixed to the horizon.

But that's not really useful, as most of the time people talk about G-force they're just talking about the force along the vertical axis of the airplane, which depends on the lift produced by the wings, and affects the structural stress (and ultimately if you're gonna black out or pop yer eyeballs).

Upright straight & level = 1 G along vertical axis
Inverted straight & level = -1 G along vertical axis
Vertical upline = 0 G along vertical axis, but 1 G longitudinally
Knifeedge flight = 0 G along vertical axis, but 1 sideways (lateral axis)

 

[belchfire]

We are definitely splitting hairs, but the ailerons change the camber of the wing, which creates lift. If you are exactly at zero lift, one aileron will be creating lift in one direction, and the other aileron will create lift in the other direction. A change in lift equals a change in drag - specifically induced drag. Differential drag from one wing to the other is the definition of adverse yaw. Being at zero lift doesn't stop adverse yaw.

My brain hurts...

Aileron travel difference would be the only cause for different change in camber from wing to wing and it is typically a fairly small difference-maybe 14 degrees down and 17-20 up-and possibly differential-ie the difference increasing towards maximum deflection but not normally more than about 30% at max deflection.

Remember that differential aileron travel is specifically intended to counteract adverse yaw. If you have asymmetric aileron travel on an aerobatic airplane that has normal category lineage (say a 150 aerobat uke: for instance) that travel would be intended for normal flight regimes-max 30 degrees of bank or so-maybe 1.3G. If the aircraft were unloaded-0G you are sticking more control surface into a relative wind of equal pressure you could come to the conclusion that the adverse yaw would be in opposite direction of normal!

It's my opinion that it's an effect that would vary greatly between aerobatic types given the wide difference in control configuration and wing shape and probably isn't a hard and fast rule...

And you thought your brain hurt!

 

[Boch]

What you're talking about is the total acceleration summed up on all axes on the plane, which is best represented by a coordinate system fixed to the horizon.

But that's not really useful, as most of the time people talk about G-force they're just talking about the force along the vertical axis of the airplane, which depends on the lift produced by the wings, and affects the structural stress (and ultimately if you're gonna black out or pop yer eyeballs).

Upright straight & level = 1 G along vertical axis
Inverted straight & level = -1 G along vertical axis
Vertical upline = 0 G along vertical axis, but 1 G longitudinally
Knifeedge flight = 0 G along vertical axis, but 1 sideways (lateral axis)
__________________
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The airplane could care less what the Gmeter in the dash has to say. Untill the limits are exceded.

Inverted straight & level = -1 G along vertical axis

G is a multiplier of gravity how are you multiplying gravity by flying straight and level while upsidedown?

 

[VNugget]

The airplane could care less what the Gmeter in the dash has to say. Untill the limits are exceded.

Uhhh, what the airplane cares about is exactly what the G meter says. That's why there's a G meter in the airplane. The more G's you pull, the more stress you put on the structure. Exceed the G limit, too much stress. What are you getting at?

G is a multiplier of gravity how are you multiplying gravity by flying straight and level while upsidedown?

You are multiplying it by -1 since it acts in the opposite direction it normally does. While upside down, gravity is acting up relative to the airplane, the G-meter reads -1, and all the junk hits the ceiling; same as if you turn your house upside down.