Path of an airplane in a 1G roll

In article , Bob Fry
wrote:

"BC" == Byron Covey writes:

BC You can't do a roll and retain 1 G positive throughout the
BC roll. BJC

There's supposed to be a video of the great Bob Hoover doing a barrel
roll with a glass of water on the panel...not a drop spilled. If
anybody knows where a copy of the video is (or if it even exists) that
would be a worth addition to Jay Honeck's collection.

All that shows is that he maintained positive G's and coordination.

A properly performed barrel roll is a 1G manuever. The aircraft's
flight path describes a helix, as David described below. An aileron
roll is a variable-G operation, since you feel -1G while inverted.

CB wrote:
A properly performed barrel roll is a 1G manuever.

Nope. It's a small amount of positive G's but it's not a constant
1G. Did you actually read David's post?

"CB" wrote
A properly performed barrel roll is a 1G manuever. The aircraft's
flight path describes a helix, as David described below. An aileron
roll is a variable-G operation, since you feel -1G while inverted.

Check the following web sites, they all contain the same paragraph.
Care to give us your references for the definition of a barrel roll.

http://www.iac.org/begin/figures.html#Barrel%20Rolls
http://acro.harvard.edu
http://web.winco.net/~efildes/slowroll/barlroll.html
The Barrel Roll is a not competition maneuver. The barrel roll is a
combination between a loop and a roll. You complete one loop while
completing one roll at the same time. The flight path during a barrel roll
has the shape of a horizontal cork screw. Imagine a big barrel, with the
airplanes wheels rolling along the inside of the barrel in a cork screw
path. During a barrel roll, the pilot experiences always positive G's. The
maximum is about 2.5 to 3 G, the minimum about 0.5 G.

Bob Moore

"CB" wrote in message

A properly performed barrel roll is a 1G manuever. The aircraft's
flight path describes a helix, as David described below.

No.

An aileron
roll is a variable-G operation, since you feel -1G while inverted.

No.

Ever done one?

moo

OK, folks, brace yourselves, you don't often see this on RAH....


I was wrong.


That's what I get for relying on an aging memory rather than looking it
up.
CB

My take on this is that an airplane in a 1G roll would follow the same
path as any other object.

Imagine your in space. A 1G roll would be a perfect circle with a
constant 1G acceleration.

Now bring that path into the Earth's gravity well. Now the 1G roll is
all messed up by the Earth's 1G. How can we fix that? Just like the
Vomit Comet does, by accelerating down at 9.8m/s^2. Superimpose a roll
on top of a parabolic descent and you have the path of a theoretical
airplane in a 1G roll.

I don't think there is a plane that could actually perform this maneuver
in reality.

--
This is by far the hardest lesson about freedom. It goes against
instinct, and morality, to just sit back and watch people make
mistakes. We want to help them, which means control them and their
decisions, but in doing so we actually hurt them (and ourselves)."

On Wed, 29 Jun 2005 04:01:56 +0100, Ernest Christley
wrote:

My take on this is that an airplane in a 1G roll would follow the same
path as any other object.

Imagine your in space. A 1G roll would be a perfect circle with a
constant 1G acceleration.

Now bring that path into the Earth's gravity well. Now the 1G roll is
all messed up by the Earth's 1G. How can we fix that? Just like the
Vomit Comet does, by accelerating down at 9.8m/s^2. Superimpose a roll
on top of a parabolic descent and you have the path of a theoretical
airplane in a 1G roll.

I don't think there is a plane that could actually perform this maneuver
in reality.

Obviously, the quicker you can roll, the easier it would be, but
essentially it would be impossible to complete a constant 1G roll back to
S&L. You would have to end up in a nose-down attitude in order to
maintain 1G while inverted. The greater your roll rate, the less time
you'll need to maintain positive G while inverted, and hence the nose
won't need to drop as far. The closest you're going to get to this is a
simple aileron roll where you start nose high... but then you've pulled
more than 1G to get the nose in to that position!



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