High G Rolling Redouts

[Yeager]

Does it make sense that plane with high rolling ability have redouts when rolling plane whip rolls or rolls for an extended period.

I was in a 190D and whip rolled that puppy about 5 times a second for 5-6 seconds.  I though to myself that I should have burst every blood vessle in my brain had I been "really" flying the damned thing.  Of course, Im not picken on this excellent gerry can.  Any plane that rolls excessively should impart a high G on the pilot.

Y

[Blue Mako]

Pure rolling does not cause any positive or negative g on the pilot.  It imparts sidewards force on the pilot in proportion to how far from the axis of the rolling motion he is.  This would not change the amount of blood pooling in any region of the body the same way that +ve and -ve g does.

[pimpjoe]

i know what he's talking about...do this blue... put your stick in the upper right or left hand corner and roll. i *think* its kinda like an "inverted" snap roll. you pull about 9 -G's while rolling.

[Tumor]

Originally posted by pimpjoe
i know what he's talking about...do this blue... put your stick in the upper right or left hand corner and roll. i *think* its kinda like an "inverted" snap roll. you pull about 9 -G's while rolling.

I'd think the initial clock you cranium put on the canopy would cause a mild contusion at least....then of course you'd wear a flat spot on the side of your skull having it plastered too it at those -g's

[Yeager]

Ok  let me understand this.  Usually in airframes the center of gravity is somewhere just below the pilots seat.  If the center of gravity is spun around on the x axis, maybe three or four times a second, the pilots body has no positive G force exterted on it?

Okay, lets try this:  Secure your self to a giant spinning wheel then have that wheel brought up to a vertical position with your head facing up (just like you were standing) then have your favourite little buddy grab that wheel and SPIN IT clockwise.

Now tell me, as you are spinning round and round, three revolutions per second, that no gravity force beyond static one G
is being exerted on your head.  If you say "No yeager, its just the same as if you were standing there picking your nose, one G" then my place in this cosmos is all fediddleed up.

Help me.

[Tac]

I want puke modelled in AH. If you roll more than 10 times in 1 second, your screen should suddenly be filled with nice yellow-green-white spots

[MANDOBLE]

Originally posted by Yeager
rolled that puppy about 5 times a second

I cant even do a single entire roll per second ...

[Blue Mako]

Sorry, posted the above when tired and not thinking too straight.

You will get centrifugal force acting on the pilot as a negative g force but it will be low compared to pulling or pushing the stick.  The centrifugal force is a function of the roll rate (to the square of roll rate actually) and the distance from the centre of rotation.  In fighter aircraft these are both relatively low.  What is the maximum roll rate of a WWII fighter?  360 deg/sec?  Probably lower I would guess.

Also, don't forget that the forces acting on the pilot will be different along his body.  While the extremity of his head is getting a certain force, his butt is under a lower force so the blood will not rush to the head the same way it would under normal g loadings.

As for your spinning wheel example, would you expect to black out if you laid down in the middle of a merry-go-round?  You'd probably get pretty dizzy and puke pretty quick but I doubt you'd black out or red out until it was spinning pretty darn fast.

I've done aeros in a pitts before.  We did multiple aileron and snap rolls that were easily greater than 1 rev per second.  I don't recall having any excessive negative g during them.  I'll have to ask se (a guy in our squad who flies competition aeros) about his experience.  I do remember having my head just about torn off sideways due to the sudden change in momentum though.

[Vruth]

I want puke modelled in AH. If you roll more than 10 times in 1 second, your screen should suddenly be filled with nice yellow-green-white spots

RFOL Tac!

But Yeager has a valid point.  All fighters have neutral flight dynamics so when you roll (not barrel roll), you can place a lot of negative g-force on your head as the plane whips around on a line.  

I was sitting on the runway when Yeager whipped over head in the Dora at around 400mph. By the looks of his flight path, he should of experienced 'redout'.

I remember seeing a video Pattie in her Extra 400 doing a series of quick rolls - she was definately experiencing negative G's (her 'wild look' hair was plastered to the canopy).  Hmm...just made me think of something else...
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Dem's fighten words!

[Toad]

Are we talking straight aileron rolls here?

Because I do remember doing 720-degree-per-second straight aileron rolls in T-38's. Well, they said it would do 720 with full stick deflection anyway.

I do remember it rolled pretty damn fast... but I don't ever remember redding out or getting slammed into the canopy sideways. I did bump my head the first few times but after you knew what to expect you could do it without bumping your helmet.

Course, that was a few years and many dead brain cells ago.

I just don't remember fast, consecutive straight aileron rolls being much a "big deal" Yeag.

Andy Bush? Come in Andy!