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.

David O wrote:

Chris W wrote:



Do we have any who is a math whiz here? I want to find a formula to
calculate the position of an airplane throughout a 1G roll. The reason
I'm doing this is so I can build a "roll track" for a remote control car
so the car will alway have a positive g force on it to keep it on the
track. Anyone have any ideas? So far my attempts have have all come up
short. They don't pass what my college calculus instructor called the
"warm and fuzzy" test. I think it has been too long since I took those
classes.



Chris,

I suggest that you forget about trying to model the path of an
airplane in a 1 G roll and, instead, make your car track a simple
helix. With a simple helix you should be able to keep your car's
front wheels straight as the car goes through the helix. Now for the
details...


Why didn't I think of that. That is a much simpler solution. I can
even do those calculations but thanks for doing them for me. If I get a
3d model going I will send you an image.

--
Chris W

Gift Giving Made Easy
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give the gifts they want
http://thewishzone.com

Chris W wrote:

If I get a
3d model going I will send you an image.

Yes, please do.

David O -- email: David at AirplaneZone dot com

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

On Wed, 22 Jun 2005 at 20:09:25 in message
, Bob Moore
wrote:
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.

That must of course be correct. To describe an actual horizontal helix
would require a lot of smooth changes in g and in necessary control
deflections, otherwise the helix would not be circular in cross section.

However perhaps there could be a manoeuvre that combines a roll with a
constant 1 g pressure on the crew?

My guess is that it would turn into rather odd sort of spiral dive. The
nose would certainly fall below a level flight path!
--
David CL Francis

Just to add to all of this about if a barrel roll is a 1G maneuver, which I
don't think it is, I was watch a Military Channel show on Boeing and
the -80/707 and Tex Johnston was talking about the barrel roll he did and
said it was a 1G maneuver.




"David CL Francis" wrote in message
...
On Wed, 22 Jun 2005 at 20:09:25 in message
, Bob Moore
wrote:
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.

That must of course be correct. To describe an actual horizontal helix
would require a lot of smooth changes in g and in necessary control
deflections, otherwise the helix would not be circular in cross section.

However perhaps there could be a manoeuvre that combines a roll with a
constant 1 g pressure on the crew?

My guess is that it would turn into rather odd sort of spiral dive. The
nose would certainly fall below a level flight path!
--
David CL Francis

On Fri, 24 Jun 2005 13:08:09 -0500, "Gig 601XL Builder"
wr.giacona@coxDOTnet wrote:

Just to add to all of this about if a barrel roll is a 1G maneuver, which I
don't think it is, I was watch a Military Channel show on Boeing and
the -80/707 and Tex Johnston was talking about the barrel roll he did and
said it was a 1G maneuver.

Think about it, sitting at the keyboard typing, and flying along in
level flight, you are at 1G. Pull back on the yoke or stick and you
are no longer at 1G, you are at 1G plus whatever it takes to climb.
It's impossible to gain altitude without experiencing more than 1G.

Could it be that the person describing the 707 barrel roll meant that
the maneuver was 1G in excess of 1G? In other words 2G's? Could be,
but probably the announcer or "talent" speaking for the clip had no
idea what he was talking about.

Corky Scott