Path of an airplane in a 1G roll

Corky Scott writes:
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.

Actually, I think Tex says it. You can watch the video clip yourself
and make up your mind, Jay has it archived on this page:

http://www.alexisparkinn.com/aviation_videos.htm

Search for "Tex" and you'll find it.

Chris
--
Chris Colohan Email: PGP: finger
Web: www.colohan.com Phone: (412)268-4751

"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.


By the definition of a barrel roll used by the International Aerobatic
Club and the US Navy where I learned to fly, Tex was of course wrong
on two counts. First as pointed out by others, anything other than
"straight and level" must incur more than 1g, and secondly, Tex's roll
was not a barrel roll.

Bob Moore

"Corky Scott" wrote in message
...
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

Well Corkster, don't tell me tell Tex Johnston. He did it and he said it. As
I said in my post I don't think it is a 1G maneuver and for that mater it
wasn't a very good barrel roll except when you consider it had never been
done in that model of airplane and even the co-pilot didn't know he was
going to do it until right before he did it.

Gig G

Not to put too fine a point on this, Corky, but you can in fact enter a
climb and still maintain 1 G downward relative to the axis of the
airplane, but you have to decelerate while starting the climb. I agree
that you can't climb at a steady rate and not experience a shift in g
forces aft, but as your bring the nose up you have to slow down as
well, to add a little negative acceleration to offset the aft shifting
gravity vector. Think of it this way. If you hang a plumb bob in the
airplane, and start a climb, the bob will shift aft. If you're in level
flight and slow down, it'll shift forward. If you combine the two
correctly, it'll stay pointing at the same spot on the floor.

If you agree with this reasoning, you'll also agree that with a fast
enough entry speed you could pull through an entire loop -- it wouldn't
be round! -- and keep the plumb bob centered over the same spot.

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.

If you hang a plumb bob in the
airplane, and start a climb, the bob will shift aft. If you're in level
flight and slow down, it'll shift forward. If you combine the two
correctly, it'll stay pointing at the same spot on the floor.

.... and the string will break.

Or at least will be under more stress. There's more than the position
of the plumb bob to the total net force.

Jose
--
You may not get what you pay for, but you sure as hell pay for what you get.
for Email, make the obvious change in the address.

Bob Moore writes:
"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.


By the definition of a barrel roll used by the International Aerobatic
Club and the US Navy where I learned to fly, Tex was of course wrong
on two counts. First as pointed out by others, anything other than
"straight and level" must incur more than 1g, and secondly, Tex's roll
was not a barrel roll.

Too much misinformation in this thread. Here is exactly what he said
(any transcription errors are my fault):

"...and I knew the prototype, and there is one maneuver you can do
with no hazard whatsoever. I decided that I would do a roll to
impress the people. So I came accross and did a chandelle..."

"...I was called into Mr. Allen's office on Monday morning, and
Mr. Allen asked me what I thought I was doing, and I explained
that I was selling airplanes. And I explained that it was a 1G
maneuver, and it was absolutely non-hazardous, and it was very
impressive."

Chris
--
Chris Colohan Email: PGP: finger
Web: www.colohan.com Phone: (412)268-4751

Chris Colohan wrote
"...and I knew the prototype, and there is one maneuver you can do
with no hazard whatsoever. I decided that I would do a roll to
impress the people. So I came accross and did a chandelle..."

Well....It certainly was NOT a chandelle, which is a climbing 180
degree change of direction.

I have in my possesion, two videos of the Dash 80 roll and in one of
them, Tex does make the statement that you attribute to him. In the
other, a one hour TV program, his quote is:

"I came back over the course, pulled the nose up, put in full aileron,
and did a nice 1g roll."

Sure looks asn sounds like an aileron roll to me.

John Steiner, a retired Boeing Vice-President, was the narrator
in the video that dubbed it a "barrel roll".

I was disappointed somewhat later in the video when Tex stated that:

"I had perfected aerobatics years and years ago and as I said, it
was a 1g maneuver."

This from the Chief Test Pilot on what was perhaps the most important
aircraft project in Boeing's history. ??????

Bob Moore
17 years in the Grand Old 707. 1967-1985

Bob Moore wrote:
Chris Colohan wrote
"...So I came accross and did a chandelle..."

Well....It certainly was NOT a chandelle, which is a climbing 180
degree change of direction.

No arguments there.

I was disappointed somewhat later in the video when Tex stated that:

"I had perfected aerobatics years and years ago and as I said, it
was a 1g maneuver."


It is probably dangerous and stupid to try to guess the meaning of
another's words taken out of context and years after the fact. OTOH,
this is usenet, so... :-)

It would seem to me that the forces acting on the airplane (and pilot)
during the part of the roll where the airplane is inverted are what
most people wouldn't understand. Tex Johnson obviously knew that one
can't fly an aileron roll or a barrel roll without pulling a little g
on the way in and on the way out. It's not hard, however, to maintain
1 positive g while the airplane is upside-down. Maybe that's what he
was talking about?

Assuming the maneuver starts with a bag full of speed, a judicious
pitch rate, an airplane capable of a reasonable roll rate, and proper
placement of the nose before starting the roll, the whole thing can be
done easily with 2-ish g's and little-to-no seat puckering. (Make a
mistake in timing or control, however, and all bets are off.) Tex knew
what he was doing, and the tape proves it.

-Dave Russell
N2S-3

On 24 Jun 2005 16:30:32 -0700, "Tony" wrote:

Not to put too fine a point on this, Corky, but you can in fact enter a
climb and still maintain 1 G downward relative to the axis of the
airplane, but you have to decelerate while starting the climb. I agree
that you can't climb at a steady rate and not experience a shift in g
forces aft, but as your bring the nose up you have to slow down as
well, to add a little negative acceleration to offset the aft shifting
gravity vector. Think of it this way. If you hang a plumb bob in the
airplane, and start a climb, the bob will shift aft. If you're in level
flight and slow down, it'll shift forward. If you combine the two
correctly, it'll stay pointing at the same spot on the floor.

If you agree with this reasoning, you'll also agree that with a fast
enough entry speed you could pull through an entire loop -- it wouldn't
be round! -- and keep the plumb bob centered over the same spot.

Tony, it doesn't matter where the plumb bob hangs, going up means
adding some force in excees of 1G to do it. No matter how gently you
do it, a sensitive enough G meter will detect the additional force
that is required.

It's kind of like trying to fake out a bathroom scale. No matter how
gently you step onto it, it will eventually read your weight.

Climbing is like pushing against an inverted scale.

Corky Scott

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