Rolling a 172 - or not

Big John wrote

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

John, have you looked at the barrel roll picture that I e-mailed
you and posted on alt.binaries.pictures.aviation?
If not, further discussion will be of no use.

Have you checked the "Willian Kershner" web site and read the
author's credentials?
If not, you just leave us wondering "who-the-hell" is Big John,
and what credence should we give to his unsupported assertions?
Mr. Kershner owns and operates an Aerobatic Flight School and
has authored the book, "The Basic Aerobatic Manual" which as he
points out, was an offshoot (with permission) of the manual he
helped write for Cessna Aircraft in 1969.

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

Here are William Kershner's words that accompanied the diagram of
the barrel roll in his The Flight Instructor's Manual in which he
devotes all of chapter 5 (66 pages) to aerobatic instruction.

Quote..............or should I say OCR'ed

THE BARREL ROLL
• Preparation. It's almost impossible to draw a barrel roll
on the chalkboard, but a model will give the desired results.
Have the trainee study the references.

•Explanation. The barrel roll is a precise maneuver in which
the airplane is rolled around an imaginary point 45° to
the original flight path. A positive-g level is maintained
throughout the maneuver, and the ball in the turn indicator
should stay in the middle.

You may wonder why the barrel roll is taught this late,
since it appears to be so simple. Well, it is a precise maneuver
requiring particular airplane attitudes at particular reference
points, which is difficult for the average trainee to do properly
at first.

This maneuver might be considered an exaggeration of the
wingover, but instead of starting to shallow the bank at the 90°
position, the pilot must steepen it continually until the airplane
has rolled 360° and is back on the original heading. The rate of
roll must be much greater than that used for the wingover
because the airplane must be in a vertical bank at 45° of turn,
and it must be inverted at 90° of turn. The roll and turn is
continued until the airplane is headed in the original direction with
the wings level. Compare the barrel roll in Fig. 23-12 with the same
view of the wingover in Fig. 20-7.

From behind the maneuver looks as though the airplane is being
flown around the outside of a barrel. This is a very good maneuver
for gaining confidence and keeping oriented while flying inverted in
balanced flight.
Good coordination is required to do the barrel roll properly and
the trainee will show an improvement in that area after a session of
barrel rolls.

The barrel roll is generally more difficult and precise than the
aileron roll, and he may have to work on this one awhile.

Why-
The barrel roll is one of the best maneuvers for improving
orientation.

Unlike the other acrobatic maneuvers covered thus far, the barrel
roll requires a constantly changing bank and pitch (with attendant
changing airspeed) and a radical change in heading (90°) while the
airplane is rolling. The average trainee probably will be looking at
the wing tip at a time when he should be checking the nose, or vice
versa.
When he is able to stay well oriented in the barrel roll, he is ready
to move on to the reverse Cuban eight or reverse cloverleaf.

How-
You might use the following explanation, or develop your own:
(1) Make sure the area is clear, then pick a reference on the
horizon off the wing tip as in the wingover and lazy eight.
(2) Set the throttle to low cruise rpm and ease the nose over to
pick-up about 10 K more than used for the wingover or set up
the airspeed used for a loop, whichever is higher. Power
adjustment should not be necessary during the maneuver. You
might have some of your sharper trainees apply full power as
the airplane approaches inverted and then remind them to
throttle back as the airspeed picks up in the last part of the
maneuver.
(3) Smoothly pull the nose up and start a coordinated climbing turn
(note that it will have to be at a much faster rate than was
used for the wingover) toward the reference point. (Assume that
at first the roll will be to the left.)
(4) When the nose is 45° from the original heading, it should be
at its highest pitch attitude and the left bank should be
vertical.
(5) When the nose is at 90° from the original heading, you should
be looking directly at the reference point that was originally
off the wing tipfrom a completely inverted position
(momentarily).
(6) When the airplane heading is again 45° from the original, the
bank is vertical but you will be in a right bank as far as the
ground is concerned; that is, the right wing is pointing
straight down at this instant of roll. The nose will be at its
lowest pitch attitude at this point.
(7) The roll is continued to wings-level flight as the nose is
raised back to the cruise attitude.

The maneuver must be symmetrical; the nose must go as far above the
horizon as below. The barrel roll requires definite checkpoints to
ensure that the airplane is at the correct attitude throughout. It is
interesting to note that if the barrel roll is to the left, all of
the airplane's path is to the left of the original line of flight and
the airplane's nose is always pointed to the left of the original
flight line (until it merges again at the completion of the
maneuver). The opposite occurs, naturally, for the barrel roll to the
right.

Another method of doing a barrel roll is to pick a reference on the
horizon, turn the airplane 45° to the reference point, and proceed to
make a wide roll around this real point. One disadvantage of this
method for the newcomer is that it depends on the pilot's own
judgment of how large the orbit around the point should be. For an
introduction to the maneuver, the first method is usually better, but
you may prefer the second and work out your own techniques of
instructing it.

Demonstration.
Try not to lose the reference point yourself while demonstrating
this one. You may find your explanation is not keeping up with the
airplane, which usually results in sputtering and stuttering while
the maneuver proceeds to its foregone conclusion -and then you have
to do a new demonstration. Don't worry, this will happen plenty of
times during your career of instructing aerobatics -when your mouth
can't keep up with your brain or the maneuver-and it can ease tension
if you react to it with humor.

Usually the trainee is surprised to see the same wing tip back on the
reference point and may confess that, like the first snap roll, the
earth and sky were blurred and he had no idea where the reference was
during the maneuver.

Practice.
You may rest assured the trainee will "lose" the reference point
during the first couple of barrel rolls. He'll usually stare over the
nose, seeingnothing but blue sky or ground and not really seeing the
point at all.

Common errors during barrel rolls include these:
1. Not pulling the nose high enough in the first 45° of the
maneuver, which means that the highest and lowest nose positions
are not symmetrical to the horizon.
2. Not maintaining a constant rate of roll. Usually things are fine
at the 45° position; the nose is at its highest pitch and the
bank is vertical.
As you approach the position of 90° of turn you will probably
find that he is not going to be completely inverted at that
point and will have to rush things a bit to make it. The usual
reason is that he did not maintain a constant rate of roll.
Remember that the nose is up and the airspeed is slower in this
segment of the maneuver, so the controls must be deflected more
to get the same rate. This is where coordination comes in. Watch
for it in particular.
3. Letting the nose drop after passing the 90° point; losing too
much altitude and gaining excess airspeed.
4. Failure to roll out on the original heading; having the wing tip
well ahead, or well behind, the reference when the maneuver is
completed.

Evaluation and Review.
Review each barrel roll briefly in the air, and have the trainee
use the model on the ground. This one can be hard to "see," so go
over it again as necessary after getting on the ground.

By the time a half-dozen barrel rolls have been practiced, the
average trainee should be oriented throughout the maneuver even
though he may still have minor problems of heading and symmetry.
After a dozen rolls he should be starting to work on a constant roll
rate and starting to ease his heading problems. After several
hundred, he may begin to be satisfied with his barrel rolls but will
realize that constant practice is required.

Unquote.................

But John...you really should look at that picture.

Bob

On Mon, 10 Nov 2003 02:02:01 GMT, Robert Moore
wrote:

----clip----

But John...you really should look at that picture.

----clip----

OK. I reconfigured my computer and subscribed to
"alt.binaries.pictures.avation" and down loaded the last 50 posts and
don't find anything from you.

I'll go back and download everything from day one to look for your
picture and then blow away the other thousands I down loaded.

Since I know what a barrel roll is and how to do same and have done
then for many many years, why should l look at a picture you drew and
if done as described by your expert I seriously doubt if anyone could
fly ???

I think I'll let you experts have the floor to do with as you choose.

I'm scheduled for a kidney x-ray tomorrow and need to go in refreshed.
(No muzzle loaders tonight - we used to call them booze berries G)

Big John

Bob

Found and subscribed to alt.binaries.pictures.avation and down
loaded all the postings in that Group. About 500 or so. Sat down and
went through them untiL I found your posting. Drilled down and finally
got the picture you are so hot about.

My comments, No one could do a barrel roll as depicted in your
picture. You show a single plane (not airplane) picture and maneuver
is done along an extended length of airspace.

You don't enter at 90 degrees to the desired direction of flight. Your
picture looks more like a single leaf of a four leaf clover.

Maybe this is what you call a barrel roll today but sure isn't the
classic maneuver.

On your query on my credentials in this post. I have answered that in
another posting. However to follow along that line since you won't let
it go, who are you to question my credentials? You sound like some
'want a be' that's never spent time on his back maybe not even a
pilot?. I may well have more inverted time than your total time????.

I can do a double emmelman in a F-80/T-33 and a slow roll in aT-6/SNJ
without the engine cutting out when inverted. Also I can do a loop in
a T-6/SNJ starting from zero indicated airspeed. Want to try any of
those maneuvers? Lets see your buddy Kershner do those.He's got T-33
time so ask him if he ever did a double emmelman in it and if so how
he did it (airspeed, altitude, G's, etc)? I've got thousands of hours
of tail wheel time and never ground looped or let one of my students
ground loop on any kind of a field and in any type of weather/wind.

BOb and I may well have the highest tail wheel time of any on this
group and he's got a lot???

Among others I have instructed both Chinese and Norwegian Air Force
students and was awarded wings from both countries, which I am
authorized by our government to wear (you need permission you know).

I am a member of the caterpillar club (

When do you want me to quit??????

The more we talk the more I disagree with you so need to shut things
down before we get violent G

If you want, take the last shot (some people just have to) and that's
it.

And the best to thee from the wee ones.

Big John


On Mon, 10 Nov 2003 02:02:01 GMT, Robert Moore
wrote:

Big John wrote

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

John, have you looked at the barrel roll picture that I e-mailed
you and posted on alt.binaries.pictures.aviation?
If not, further discussion will be of no use.

Have you checked the "Willian Kershner" web site and read the
author's credentials?
If not, you just leave us wondering "who-the-hell" is Big John,
and what credence should we give to his unsupported assertions?
Mr. Kershner owns and operates an Aerobatic Flight School and
has authored the book, "The Basic Aerobatic Manual" which as he
points out, was an offshoot (with permission) of the manual he
helped write for Cessna Aircraft in 1969.

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

Here are William Kershner's words that accompanied the diagram of
the barrel roll in his The Flight Instructor's Manual in which he
devotes all of chapter 5 (66 pages) to aerobatic instruction.

Quote..............or should I say OCR'ed

THE BARREL ROLL
• Preparation. It's almost impossible to draw a barrel roll
on the chalkboard, but a model will give the desired results.
Have the trainee study the references.

•Explanation. The barrel roll is a precise maneuver in which
the airplane is rolled around an imaginary point 45° to
the original flight path. A positive-g level is maintained
throughout the maneuver, and the ball in the turn indicator
should stay in the middle.

You may wonder why the barrel roll is taught this late,
since it appears to be so simple. Well, it is a precise maneuver
requiring particular airplane attitudes at particular reference
points, which is difficult for the average trainee to do properly
at first.

This maneuver might be considered an exaggeration of the
wingover, but instead of starting to shallow the bank at the 90°
position, the pilot must steepen it continually until the airplane
has rolled 360° and is back on the original heading. The rate of
roll must be much greater than that used for the wingover
because the airplane must be in a vertical bank at 45° of turn,
and it must be inverted at 90° of turn. The roll and turn is
continued until the airplane is headed in the original direction with
the wings level. Compare the barrel roll in Fig. 23-12 with the same
view of the wingover in Fig. 20-7.

From behind the maneuver looks as though the airplane is being
flown around the outside of a barrel. This is a very good maneuver
for gaining confidence and keeping oriented while flying inverted in
balanced flight.
Good coordination is required to do the barrel roll properly and
the trainee will show an improvement in that area after a session of
barrel rolls.

The barrel roll is generally more difficult and precise than the
aileron roll, and he may have to work on this one awhile.

Why-
The barrel roll is one of the best maneuvers for improving
orientation.

Unlike the other acrobatic maneuvers covered thus far, the barrel
roll requires a constantly changing bank and pitch (with attendant
changing airspeed) and a radical change in heading (90°) while the
airplane is rolling. The average trainee probably will be looking at
the wing tip at a time when he should be checking the nose, or vice
versa.
When he is able to stay well oriented in the barrel roll, he is ready
to move on to the reverse Cuban eight or reverse cloverleaf.

How-
You might use the following explanation, or develop your own:
(1) Make sure the area is clear, then pick a reference on the
horizon off the wing tip as in the wingover and lazy eight.
(2) Set the throttle to low cruise rpm and ease the nose over to
pick-up about 10 K more than used for the wingover or set up
the airspeed used for a loop, whichever is higher. Power
adjustment should not be necessary during the maneuver. You
might have some of your sharper trainees apply full power as
the airplane approaches inverted and then remind them to
throttle back as the airspeed picks up in the last part of the
maneuver.
(3) Smoothly pull the nose up and start a coordinated climbing turn
(note that it will have to be at a much faster rate than was
used for the wingover) toward the reference point. (Assume that
at first the roll will be to the left.)
(4) When the nose is 45° from the original heading, it should be
at its highest pitch attitude and the left bank should be
vertical.
(5) When the nose is at 90° from the original heading, you should
be looking directly at the reference point that was originally
off the wing tipfrom a completely inverted position
(momentarily).
(6) When the airplane heading is again 45° from the original, the
bank is vertical but you will be in a right bank as far as the
ground is concerned; that is, the right wing is pointing
straight down at this instant of roll. The nose will be at its
lowest pitch attitude at this point.
(7) The roll is continued to wings-level flight as the nose is
raised back to the cruise attitude.

The maneuver must be symmetrical; the nose must go as far above the
horizon as below. The barrel roll requires definite checkpoints to
ensure that the airplane is at the correct attitude throughout. It is
interesting to note that if the barrel roll is to the left, all of
the airplane's path is to the left of the original line of flight and
the airplane's nose is always pointed to the left of the original
flight line (until it merges again at the completion of the
maneuver). The opposite occurs, naturally, for the barrel roll to the
right.

Another method of doing a barrel roll is to pick a reference on the
horizon, turn the airplane 45° to the reference point, and proceed to
make a wide roll around this real point. One disadvantage of this
method for the newcomer is that it depends on the pilot's own
judgment of how large the orbit around the point should be. For an
introduction to the maneuver, the first method is usually better, but
you may prefer the second and work out your own techniques of
instructing it.

Demonstration.
Try not to lose the reference point yourself while demonstrating
this one. You may find your explanation is not keeping up with the
airplane, which usually results in sputtering and stuttering while
the maneuver proceeds to its foregone conclusion -and then you have
to do a new demonstration. Don't worry, this will happen plenty of
times during your career of instructing aerobatics -when your mouth
can't keep up with your brain or the maneuver-and it can ease tension
if you react to it with humor.

Usually the trainee is surprised to see the same wing tip back on the
reference point and may confess that, like the first snap roll, the
earth and sky were blurred and he had no idea where the reference was
during the maneuver.

Practice.
You may rest assured the trainee will "lose" the reference point
during the first couple of barrel rolls. He'll usually stare over the
nose, seeingnothing but blue sky or ground and not really seeing the
point at all.

Common errors during barrel rolls include these:
1. Not pulling the nose high enough in the first 45° of the
maneuver, which means that the highest and lowest nose positions
are not symmetrical to the horizon.
2. Not maintaining a constant rate of roll. Usually things are fine
at the 45° position; the nose is at its highest pitch and the
bank is vertical.
As you approach the position of 90° of turn you will probably
find that he is not going to be completely inverted at that
point and will have to rush things a bit to make it. The usual
reason is that he did not maintain a constant rate of roll.
Remember that the nose is up and the airspeed is slower in this
segment of the maneuver, so the controls must be deflected more
to get the same rate. This is where coordination comes in. Watch
for it in particular.
3. Letting the nose drop after passing the 90° point; losing too
much altitude and gaining excess airspeed.
4. Failure to roll out on the original heading; having the wing tip
well ahead, or well behind, the reference when the maneuver is
completed.

Evaluation and Review.
Review each barrel roll briefly in the air, and have the trainee
use the model on the ground. This one can be hard to "see," so go
over it again as necessary after getting on the ground.

By the time a half-dozen barrel rolls have been practiced, the
average trainee should be oriented throughout the maneuver even
though he may still have minor problems of heading and symmetry.
After a dozen rolls he should be starting to work on a constant roll
rate and starting to ease his heading problems. After several
hundred, he may begin to be satisfied with his barrel rolls but will
realize that constant practice is required.

Unquote.................

But John...you really should look at that picture.

Bob

Big John wrote

My comments, No one could do a barrel roll as depicted in your
picture. You show a single plane (not airplane) picture and
maneuver is done along an extended length of airspace.

Not "my" picture. Was scanned from Mr. Kershner's book.

Maybe this is what you call a barrel roll today but sure isn't
the classic maneuver.

Same maneuver that I was taught in the T-28 back in 1958.
Check-out this web site:

http://web.winco.net/~efildes/slowroll/barlroll.html

On your query on my credentials in this post. I have answered
that in another posting. However to follow along that line since
you won't let it go, who are you to question my credentials? You
sound like some 'want a be' that's never spent time on his back
maybe not even a pilot?. I may well have more inverted time than
your total time????.

20,000+ hours inverted??? Wow! That's a lot John.
My last aerobatic instructing was done as recently as 1998 in the
YAK-52. Great little airplane....good for +7g's. It combined the
performance of the Navy T-28B (1425 hp) in a T-34 size airframe.
BTW, in addition to a few thousand hours instructing in Boeing
jetliners, I have been an FAA certificated flight instructor since
1970. Spent the years 1993-99 teaching in C-172s.

BOb and I may well have the highest tail wheel time of any on
this group and he's got a lot???

Well, I built my own tailwheel airplane and flew it for 10 years.
It was exhibited at the Sun-n-Fun airshow in 1991 and 1992.
According to the factory that provided the kit,(TEAM) I was the first
and probably only person to spin the MiniMax.

Now....in summary, the following three web sites (documentation)
assert that the barrel roll is a combination of a loop and a roll.
But....Big John (no documentation) insists that there is no loop in
a barrel roll.

http://web.winco.net/~efildes/slowroll/barlroll.html
http://acro.harvard.edu
http://www.kershnerflightmanuals.com/

Bob Moore
ATP B-727 B-707 B-720 L-188
CFI A/I AGI IGI
USN S-2F P-2V P-3B