Rolling a 172 - or not

"Happy Dog" wrote in message
.. .
"vincent p. norris" wrote in message
You don't have positive G all the way around in an aileron roll.

In a properly done aileron roll you certainly do...

Were you thinking of a slow roll?

I know the diffference between a slow roll and an aileron roll.

If you think you maintain positive G in an aileron roll,

(1). Take along a bottle of water and a drinking glass next time you
fly.

(2). Fill the glass with water and place it atop the instrument
panel.

(3). Do an aileron roll.

Which proves what? Place a glass of water atop the instrument panel and
execute a steep turn. It won't stay there, Are you saying that a steep
turn isn't a positive G manoeuvre? You haven't thought this through...

le moo


If you stay coordinated it certainly will stay. Ever see the video of
Hoover pouring a glass of water while doing a roll.

"Happy Dog" wrote
Which proves what? Place a glass of water atop the instrument
panel and execute a steep turn. It won't stay there,

It should!!! If not, you're not using the controls properly.
I teach my students to execute co-ordinated steep turns,
doesn't everyone do it that way???

Bob Moore
ATP CFI

Big John wrote
1. A 'barrel roll' is a roll where (if done properly) you as a
passenger, with your eyes closed, can not tell you did a roll.
The ball stays centered and if one 'G' is maintained, it feels
like straight and level flight. Starting nose position and of
course air speed varies between underpoweed GA aircraft and
super sonic Fghters.
There are also a few fine points the experts use that I have not
covered but above are the basics.

Been there done that for longer (65 years) than BOb has been
flying. )

I have e-mailed BigJohn and posted at:

alt.binaries.pictures.aviation

a scan from William Kershner's book, The Flight Instructor's
Manual, in which he describes the barrel roll as an acrobatic
maneuver. You probably know that Mr. Kershner is one of the most
respected names in the flight training field, having authored
several books on the subject. Not as funny as Machado, but he has
been around for a much longer period of time.
I haven't scanned and OCRed the text because I think that the
picture is self-explanitory, but if it would help, I will do the
page of text describing the barrel roll.

Note that as mentioned in my previous post quoting from:

http://acro.harvard.edu

that one cannot maintain "one G" in a barrel roll since it involves
both a loop and a roll. In order to perform the loop portion, one
must pull at least 3-3.5 Gs in the pull-up and a similiar force in
the pull-out. While inverted, the g-force drops to .5-1 g as in a
normal loop.

I readily conceed that Big John as been around a bit longer than I,
but by the the time that I flew in the military, we were learning
to fly in "airplanes", not "birds". :-) :-)

Bob

"Dave Stadt" wrote in message

(2). Fill the glass with water and place it atop the instrument
panel.

(3). Do an aileron roll.

Which proves what? Place a glass of water atop the instrument panel and
execute a steep turn. It won't stay there, Are you saying that a steep
turn isn't a positive G manoeuvre? You haven't thought this through...


If you stay coordinated it certainly will stay. Ever see the video of
Hoover pouring a glass of water while doing a roll.

If you stay *perfectly* coordinated. I would have no problem demonstrating
an aileron roll with a cup of MacDonald's most dangerous firmly secured in
my lap. (Filled to no more than a couple inches below the brim.) I have a
key fob that I sometimes watch during aerobatic manoeuvres. It doesn't move
much during coordinated 1G stuff. But it moves a bit.

le moo

"Robert Moore" wrote in message
. 8...
"Happy Dog" wrote
Which proves what? Place a glass of water atop the instrument
panel and execute a steep turn. It won't stay there,

It should!!! If not, you're not using the controls properly.
I teach my students to execute co-ordinated steep turns,
doesn't everyone do it that way???

The point is that it will likely move, not because there is a negative G
situation, but because it takes very little lateral G force to knock it off.
Have you actually tried this? Three times in a row?

le moo

In article ,
Big John wrote:

[...]

3. An aileron roll is just laying the aileron over (normally full
aileron) and letting bird roll. Depending on type of aircraft (fighter
or GA) the nose makes a circle around a point. Fighters can do at
cruise with little or no nose above the horizon. GA requires a start
with the nose above the horizon due to slower rate of roll and bird
ending up nose low because no other control input to hold nose up
while inverted is used

The question for me -- and what prompted my earlier posting(s) -- is
whether it's possible to do a standard aileron roll and get negative G's
(or non-positive G's, to be precise). The puny GA planes I fly all have
positive G forces all the way around an aileron roll (unless you do
something funny with elevator and / or rudder), but is that true of all
aircraft?

Hamish

Robert

You talk about doing a LOOP in association with a roll. A LOOP has no
roll in it.The ailerons are only used to keep the wings 90 degrees to
the plane of the loop. A IMMELMAN or CUBAN EIGHT has a roll
associated with part of a loop.

The description of making a corkscrew inside a tube is another way of
defining the flight of the airplane when it does a BARREL ROLL.

In my prior post I said to pull one 'G' when I should have said two
'G'. Same 'G' as pulled in a one 'G' turn (one gravity 'G' and one
acceleration 'G').

Not sure you would or would not call a barrel roll a compition
maneuver. Never flew in compiton. In the airshows we used to put on
didn't do BARREL ROLLS becaue they were not very spectular from the
ground nor percicsion manuevers..

In airshows many times we would do a 8 point SLOW ROLL stoppmg
momentarily every 45 degrees of roll. This is a precison maneuver and
takes a lot of practice with elevator, rudder and aileron in
coordination to do correctly and with precision so looks good from
ground. Seen in compition today.

My reference is years and years of doing acrobatics and teaching same
in both conventional aircraft and jets.

As a matter of interest, most of the victory rolls you see of Fighters
returning from a combat mission with kills are aileron rolls. You
could see some (rare) put a little forward stick in when inverted but
had to look close.

Some birds didn't do good aileron rolls (P-51 for instanace) If you
did an aileron roll on the deck you normally bumped the stick upside
down to keep the nose up. The P-40 however aileron rolled like a spool
on a thread.

Big John


On Sun, 09 Nov 2003 03:55:51 GMT, Robert Moore
wrote:

Big John wrote
1. A 'barrel roll' is a roll where (if done properly) you as a
passenger, with your eyes closed, can not tell you did a roll.
The ball stays centered and if one 'G' is maintained, it feels
like straight and level flight. Starting nose position and of
course air speed varies between underpoweed GA aircraft and
super sonic Fghters.

Hey John, I didn't make-up that post, it came straight from:

http://acro.harvard.edu

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.

Care to give us a reference for your definition?

Bob

Big John wrote

You talk about doing a LOOP in association with a roll.

No John, I didn't talk or write about...... I just quoted from the
acro.harvard.edu web site and William Kershner's fine book.
You may not have seen the picture from the Kershner book when you
wrote this, but write back when you have seen the barrel roll as
described by someone who is considered an authority in the field.

My reference is years and years of doing acrobatics and teaching
same in both conventional aircraft and jets.

Still waiting for reference documentation. :-)

Bob

Big John wrote

My reference is years and years of doing acrobatics and teaching
same in both conventional aircraft and jets.

Check-out Mr. William Kershner at:

http://www.kershnerflightmanuals.com/

Bob

Robert

Talk me through a loop doing a Barrel Roll. We must be using different
words or maneuvers?

First let me try a different set of words for a GA barrel roll.

1. Drop the nose and pick up 20-25 mph.
2. Start a nose low left turn in the shallow dive and turn 20-30
degrees.
3, Start pulling nose up and reversing turn using 1 'G' of
acceleration (plus 1 G of gravity).
4. Continue the constant rate of roll and the 2 'G's on aircraft.
5. After passing the inverted position continue roll pulling the 2 G's
until bird is back with wings level.
6. Ending nose may be level or down depending on aircraft, starting
airspeed and rate of roll.

You can make a tight barrel roll pulling more that the 2 G's if you
want and using more aileron. If tighter will go around faster of
course.

Now your turn with the help of the guy who wrote the book you read.

Don't know what base you got your Pilot training at and the years. I
was at Willie from '49 to '53 and taught Basic. Advanced and Gunnery.

The Pilots always used the acronym "Bird". Lots of the paper forms
that we filled out used the word 'aircraft' however.

On a 172,. I'd do a barrel roll in the bird but not a slow roll or
aileron roll .Either would over stress the bird 99 times out of a
hundred.

Enough. Let the others have the stage now.

Big John


On Sun, 09 Nov 2003 14:54:09 GMT, Robert Moore
wrote:

Big John wrote
1. A 'barrel roll' is a roll where (if done properly) you as a
passenger, with your eyes closed, can not tell you did a roll.
The ball stays centered and if one 'G' is maintained, it feels
like straight and level flight. Starting nose position and of
course air speed varies between underpoweed GA aircraft and
super sonic Fghters.
There are also a few fine points the experts use that I have not
covered but above are the basics.

Been there done that for longer (65 years) than BOb has been
flying. )

I have e-mailed BigJohn and posted at:

alt.binaries.pictures.aviation

a scan from William Kershner's book, The Flight Instructor's
Manual, in which he describes the barrel roll as an acrobatic
maneuver. You probably know that Mr. Kershner is one of the most
respected names in the flight training field, having authored
several books on the subject. Not as funny as Machado, but he has
been around for a much longer period of time.
I haven't scanned and OCRed the text because I think that the
picture is self-explanitory, but if it would help, I will do the
page of text describing the barrel roll.

Note that as mentioned in my previous post quoting from:

http://acro.harvard.edu

that one cannot maintain "one G" in a barrel roll since it involves
both a loop and a roll. In order to perform the loop portion, one
must pull at least 3-3.5 Gs in the pull-up and a similiar force in
the pull-out. While inverted, the g-force drops to .5-1 g as in a
normal loop.

I readily conceed that Big John as been around a bit longer than I,
but by the the time that I flew in the military, we were learning
to fly in "airplanes", not "birds". :-) :-)

Bob