barrel roll in 172

"Matt Whiting" wrote in message
...
Big John wrote:

Andrey

As has been said in all the posts, the short answer is NO. 172 is not
certified to do barrel rolls.

However I can barrel roll a 172 only pulling 1 G which puts no more
load on airframe than straight and level flight. I have thousands of
hours to back up my statement.

Your thousands of hours aside, this is simply an incorrect statement. A
barrel roll requires flying a loop and you can't fly a loop at 1 G. It
sounds like you are describing an aileron roll.

Matt

I think what John meant was that once you start the roll by blending in
aileron, you can "adjust" in pitch to any g you want. Naturally, in the
initial pull to the roll initiation point, (assuming a straight pull with a
rolloff into the barrel roll, you will be pulling more than +1g. A lot of
people have trouble visualizing this "split" between the roll entry and the
roll itself and naturally include the pulling g into the roll to arrive at a
higher g required to do a barrel roll.
The truth of it is, once that aileron is blended in and the airplane is
rolling through 3 dimensional space, you can actually unload it all the way
down to 0 g and improve the roll rate, which is exactly the way many fighter
pilots do these 3 dimensional rolls in an ACM environment. Some fighters
like the F100 and the F4 (at certain aoa and airspeeds) can be barreled (any
roll done in both the vertical and horizontal maneuvering planes using all
three dimensions is a barrel roll :-)) using rudder alone. It must be
assumed of course that positive g must be re-aquired on the back side during
the recovery back to level flight.
But make no mistake, you can play around quite a bit with the g during the
area of the roll between the two knife edges by playing the pitch you are
using during that phase of the roll :-))
I've done barrel rolls deep in the left side of the envelope using hard
inside rudder in high performance jets that you would swear were snap
rolls!! :-))
Dudley Henriques

What does "dished out" mean?


Matt, this and your previous post show you do not have a broad knowledge
of the world of aerobatics. Please do not dispute those that do.
Your condescending tone is most inappropriate.

What does "dished out" mean? I've never heard the term. My question is
neutral.

Jose
--
The monkey turns the crank and thinks he's making the music.
for Email, make the obvious change in the address.

Did a Boeing Test Pilot barrel barrel roll a 707 over the boat races
on Lake Washington without any damage to aircraft. YES.

No, it wasn't a barrel roll, it was an aileron roll. (At least this is
what I've been told, and it makes a lot of sense.)

Someone correct me if I'm wrong, but isn't an aileron roll a negative 1 G
maneuver? You spin on an axis, through the plane's center of gravity. For
an instant, the pilot is upside down, hanging by the belt.

Mr. Boeing would not be pleased if all of the gas and oil was on the top of
the tank, away from the fuel and oil pickups.

The 707 roll was indeed a barrel roll. Check it out on Jay's webpage.
--
Jim in NC

Dudley Henriques wrote
I've done barrel rolls deep in the left side of the envelope using
hard inside rudder in high performance jets that you would swear were
snap rolls!! :-))

Dudley, what source do you use for your definition of a "barrel roll"?

Bob Moore

"Bob Moore" wrote in message
. 122...
Dudley Henriques wrote
I've done barrel rolls deep in the left side of the envelope using
hard inside rudder in high performance jets that you would swear were
snap rolls!! :-))

Dudley, what source do you use for your definition of a "barrel roll"?

Bob Moore

Well, after teaching them and doing them for fifty years, I guess I could
use myself as a source. I know of at least one major aviation magazine and
one major book on airshow safety who have used me as an aerobatic source
anyway :-)
That pushed aside for obvious reasons of propriety, your IAC source is fine,
as is your good Navy training .
Remember Bob; the military usually teaches barrel rolls in the classic
format for primary, which is as a precision maneuver using specific points
of reference to be obtained during each segment of the maneuver. You usually
don't get into variations of 3 dimensional maneuvering until lead in basic
BFM and ACM.
I also probably taught barrel rolls to primary aerobatic students the same
way you learned them in the Navy. Advanced maneuvering is another matter.
Just remember when discussing barrel rolls; there are only two ways to move
an airplane through three dimensional space. You can maneuver it using a two
dimensional maneuver through three dimensional space, or you can maneuver it
using a three dimensional maneuver through three dimensional space...and
that three dimensional maneuver is a barrel roll, no matter how tight or how
loosely you fly through the roll. Any roll, no matter how it's done, that
moves the airplane "around that barrel" is a barrel roll. If you want to do
it using the points system with the nose pointed exactly 90 degrees to the
entry heading at the inverted point, that's fine. That's a barrel roll. If
you want to pitch into the vertical line, and roll off that lineputting the
pole in the left or right corner of the cockpit winding it through like a
cork screw, that's also a barrel roll. As long as you have three dimensions
in play during the roll, its a barrel roll.

I seem to remember the Navy defining barrel rolls in the J Stage of training
in the F9F-8 Cougar as a shallow dive at about 95% to 350kts; level off and
trim; then roll the airplane around a point 45 degrees off the nose to
either side; initial acelleration to about 3g's; the nose should reach a
point about 45 degrees above the horizon at the 90 degree point; the roll
rate was adjusted to achieve a 90 degree heading change at the 180 degree
point inverted; ; you looked for about 180 to 200 kts at the top inverted
where you were looking at about 1+g if you did it right; as the nose came
through the back side, you adjusted the roll rate to nail level flight again
at your initial entry speed of 350kts. You would play the g from the initial
3 during the entry down to the 1 at the top, then play back in the 3 during
the recovery back to level flight.

This is a good way to teach a barrel roll, adjusting the speed and roll rate
a bit of course for something like the SNJ :-))

But all this dosen't change the fact that a barrel roll can be done much
tighter than this and doing it that way dosen't change the fact that you are
doing a barrel roll :-))

Dudley

john smith wrote:
In article ,
Matt Whiting wrote:


Dudley Henriques wrote:


Scotty McCray flew a Schweizer 2-22 EK for his demonstrations. We appeared
at the same shows many many times and I knew him quite well.
The 2-22 wasn't exactly the "cleanest" glider in the world by today's
standards. Scotty was an absolute master at energy control. His technique
for energy management was in my opinion the best I've ever seen done in an
unpowered aircraft. I think I watched Scotty perform hundreds of barrel
rolls in the 2-22 and never once did I see him dish it out of a roll.
Strangely enough, it was the addition of horsepower to his aerobatics that
killed him down in Brazil in 73, when the Decathlon he dished out of a low
altitude roll.
One of the nicest and finest guys I knew in aviation.
Dudley Henriques


What does "dished out" mean?


Matt, this and your previous post show you do not have a broad knowledge
of the world of aerobatics. Please do not dispute those that do.
Your condescending tone is most inappropriate.

I've never claimed broad knowledge of aerobatics. I do have a pretty
good grasp of physics though and the comment about the barrel roll
violates physics (as well as published descriptions of the forces
incurred in executing a barrel roll).

Matt

Dudley Henriques wrote:

"Matt Whiting" wrote in message
...

Dudley Henriques wrote:


Scotty McCray flew a Schweizer 2-22 EK for his demonstrations. We
appeared at the same shows many many times and I knew him quite well.
The 2-22 wasn't exactly the "cleanest" glider in the world by today's
standards. Scotty was an absolute master at energy control. His technique
for energy management was in my opinion the best I've ever seen done in
an unpowered aircraft. I think I watched Scotty perform hundreds of
barrel rolls in the 2-22 and never once did I see him dish it out of a
roll.
Strangely enough, it was the addition of horsepower to his aerobatics
that killed him down in Brazil in 73, when the Decathlon he dished out of
a low altitude roll.
One of the nicest and finest guys I knew in aviation.
Dudley Henriques

What does "dished out" mean?

Matt


When you do a roll, the second half of the roll requires changing rudder and
blending stick in elevator and aileron. If you are late on the rudder
change, or late on the elevator blending out from forward elevator to back
elevator, its possible to allow the airplane to change from rolling on its
longitudinal axis to an arc through the back side recovery. Basically what
happens is that you "slide" off the roll axis and widen the roll nose low
through the arc. In effect, you are changing the aircraft's roll axis from a
controlled slow roll to an aileron roll format, which is primarily aileron
and allows the nose to arc naturally during the roll unlike the slow roll
format where the airplane is "flown" through the entire roll from the roll
initiation at the apex of the pull on the airplane's longitudinal axis.
We call this coming in late and allowing this to happen on the back side
"dishing out" of the roll. Allowing this to happen is one of the major
killers, if not THE major killer of pilots doing low altitude roll
maneuvers.
Not allowing dishout on a roll is so critical in low altitude demonstration
work that when I practiced slow rolls for demonstration purposes, I would
set the airplane on the roll apex at it's inverted nose attitude while right
side up after a pull to the set point from a point where the altimeter
needle was covering the 0 on the altimeter, then roll the airplane from the
initiation point returning the needle to recover the 0 again as level flight
was achieved again on recovery. Any deviation from that standard was
considered a blown roll, and the entire practice session would have to be
re-flown.
Dudley Henriques

I think I got it, but this is a case where a graphic would be worth a
thousand words! :-)

Do you know of any web graphics that illustrate this error?


Matt

Peter R. wrote:

Matt Whiting wrote:


Your thousands of hours aside, this is simply an incorrect statement. A
barrel roll requires flying a loop and you can't fly a loop at 1 G. It
sounds like you are describing an aileron roll.


The descriptions from the aerobatic website, it appears, disagree with your
understanding of a barrel roll and aileron roll:

http://www.iac.org/begin/figures.html#Aileron%20Rolls

How so? It says that you pull from 0.5g at the minimum to between 2.5
and 3g at the maximum during a barrel roll. That is far different than
having a constant 1g acceleration as the OP said.

Matt

Dudley Henriques wrote
I seem to remember the Navy defining barrel rolls in the J Stage of
training in the F9F-8 Cougar as a shallow dive at about 95% to 350kts;
level off and trim; then roll the airplane around a point 45 degrees
off the nose to either side; initial acelleration to about 3g's; the
nose should reach a point about 45 degrees above the horizon at the 90
degree point; the roll rate was adjusted to achieve a 90 degree
heading change at the 180 degree point inverted; ; you looked for
about 180 to 200 kts at the top inverted where you were looking at
about 1+g if you did it right; as the nose came through the back side,
you adjusted the roll rate to nail level flight again at your initial
entry speed of 350kts. You would play the g from the initial 3 during
the entry down to the 1 at the top, then play back in the 3 during the
recovery back to level flight.

And that seems to be the way that the IAC defines a barrel roll at the
posted reference. They and the Navy make no reference for doing them
any other way. Neither does William Kernsher who has an oustanding
reputation for instructing and writing books on aerobatic instruction.

But all this dosen't change the fact that a barrel roll can be done
much tighter than this and doing it that way dosen't change the fact
that you are doing a barrel roll :-))

Just point me to the references that make this point. :-)

Bob Moore

Stefan

I'm glad your the expert.

I used to do half of a barrel roll at one G and give to student under
the hood upside down to recover.

Bird of course was acro rated but student couldn't tell we had rolled
inverted and we were pulling 1 G positive when handed over.

Big John
`````````````````````````````````

On Thu, 20 Jul 2006 21:35:26 +0200, Stefan
wrote:

Big John schrieb:

However I can barrel roll a 172 only pulling 1 G which puts no more
load on airframe than straight and level flight. I have thousands of
hours to back up my statement.

No, you can't do a barrel roll without pulling more than 1g.

Did a Boeing Test Pilot barrel barrel roll a 707 over the boat races
on Lake Washington without any damage to aircraft. YES.

No, it wasn't a barrel roll, it was an aileron roll. (At least this is
what I've been told, and it makes a lot of sense.)

Stefan