barrel roll in 172

Unfortunately I do. Most of them are crash films. I believe you can catch a
glimpse of what I'm talking about by viewing Hoof Proudfoot's P38 crash in
the UK. You can find that on Jay Honeck's aviation film page on his site. I
should point out strongly along with this that when viewing the film, you
should realize that the dishout during Hoof's second roll (the one that
killed him) was artifically caused by what both the accident investigation
board and I believe was the intervention with his control yoke by the
kneeboard he was wearing.
Regardless of the cause, dishing out of the second roll was what nailed him.
Dudley Henriques

"Matt Whiting" wrote in message
...
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

"Matt Whiting" wrote in message
...
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

Don't mean to rankle anybody here, and I haven't seen any "condescending
tone" as yet, but how does any comment made by me about barrel rolls violate
the laws of physics?
Dudley Henriques

Dudley Henriques wrote:
"Matt Whiting" wrote in message
...

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


Don't mean to rankle anybody here, and I haven't seen any "condescending
tone" as yet, but how does any comment made by me about barrel rolls violate
the laws of physics?

I don't think I understood all of your descriptions of the variations of
a barrel roll well enough to make an assessment. Some of them didn't
sound like the traditional barrel roll description. For example, do you
end up at the starting altitude in all of the cases you discussed
related to fighter evasive techniques? If you lose a lot of altitude
during the roll, then I can see being able to hold less than 1g through
most of the maneuver. I don't see how this is possible for any roll
that could be superimposed on a cylinder (the barrel) with the ending
point being at the same radial location as the starting point - that is
if you start at the bottom of the barrel you end at the bottom of the
barrel. I couldn't visualize all of your permutations on the roll to
know if this was the case or not.


Matt

Dudley Henriques wrote:

Don't mean to rankle anybody here, and I haven't seen any "condescending
tone" as yet, but how does any comment made by me about barrel rolls violate
the laws of physics?

Yes, I thought I was simply challenging a statement, not being
condescending. However, some folks take any challenge as being
condescending by definition.


Matt

"Bob Moore" wrote in message
. 121...
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

I see.

Well, I have been using Bill Kershner myself for as many years as he's been
publishing and am in complete agreement with both his and the service ways
of defining barrel rolls. I think what you and I have going here is a matter
of definition within the definition so to speak, which admittidedly can be a
bit confusing. :-))
All this means is that we're saying the same things only defining it
somewhat differently. I'm simply defining it a bit deeper by shrinking the
area in which the roll can be performed. Everything else is the same.
Let me put it this way. Both Kershner and the Navy have chosen a specific
set of parameters to define the execution of a barrel roll. These parameters
are fine, and are in use on a daily basis by most competent instructors
teaching aerobatics.

What I'm saying is that the same identical 3 dimensional roll described by
both Kershner and the Navy can be performed to much tighter parameters.
The main point of defining a barrel roll isn't the size of the roll, or the
points chosen by any particular reference source to define how the roll
should be done, but the fact that the roll takes the airplane through 3
dimensional space using a 3 dimensional maneuver. This is a unique maneuver
that we define as a barrel roll. It's a barrel roll if it's tight, and its a
barrel roll if its flown to the specifications used by either Kershner or
the Navy.
All Kershner and the Navy have done is to choose one specific set of
parameters that define a barrel roll for training purposes. What they have
done is choose parameters to produce a maximum training result, and they are
correct to have done it this way. As I have said, I also have taught barrel
rolls this way.
I'm also saying however, that any roll flown through three dimensional space
using a three dimensional maneuver can be defined as a barrel roll. In BFM
and ACM, there are other terms used for these rolls. They can be called
"displacement or lag rolls" for example, where an attacker will go out of
plane and perform a 3 dimensional roll opposite the defender's flight path
to regain angle off and maintain nose to tail separation to avoid an
overshoot in the plane of the defender. The main point is that if this roll
goes through 3 dimensions, its a barrel roll.
If you want a Navy source to confirm all this , simply copy what I've said
here and drop it in an email to either TPS (the test pilot school at Pax),
or out to Top Gun at Miramar. I believe they will verify for you if need be.
Dudley Henriques

"Matt Whiting" wrote in message
...
Dudley Henriques wrote:

Don't mean to rankle anybody here, and I haven't seen any "condescending
tone" as yet, but how does any comment made by me about barrel rolls
violate the laws of physics?

Yes, I thought I was simply challenging a statement, not being
condescending. However, some folks take any challenge as being
condescending by definition.


Matt

Well, as long as I'm not one of them, I think we have the makings of a
dialog going here :-))
DH

On 20 Jul 2006 15:22:10 GMT, Andrey Serbinenko
wrote:

What I was hoping to hear was an opinion of someone who's familiar with
what is involved in test-flying for normal/utility category and how much
it covers the type of stress imposed on the airframe and systems in a barrel
roll.

As others have pointed out, it is NOT legal, at least in the U.S. But
it certainly possible, and just as certainly inadvisable. Any plane
can be barrel rolled... I seem to recall that someboy barrel rolled a
747 at the Paris Air Show around 30 years ago.

Many years ago when I was much younger and much more foolish, I looped
and rolled 172's a few times. Foolish, as I said, as only a teenage
boy can be (they sometimes call it "young man's immortality syndrome")
even though I had some acro training, and lucky that I didn't screw up
and overstress and/or overspeed the plane. It's just not designed for
that kind of thing. It was a bad idea then and and a bad idea now and
I would NOT attempt it today (not that I've even flown a 172 in the
past 25 years or so).

-Dana
--
--
If replying by email, please make the obvious changes.
-------------------------------------------------------------------------------
The most useful tool for dealing with management types is, of course, an automatic weapon.

See inserts;


"Matt Whiting" wrote in message
...
Dudley Henriques wrote:


Don't mean to rankle anybody here, and I haven't seen any "condescending
tone" as yet, but how does any comment made by me about barrel rolls
violate the laws of physics?

I don't think I understood all of your descriptions of the variations of a
barrel roll well enough to make an assessment. Some of them didn't sound
like the traditional barrel roll description.

You were right. Some of them are not from the classic description. This is
what confuses this issue so often when discussing it. The "classic" barrel
roll description is absolutely correct. Its just possible to perform the
maneuver to tighter specifications that's all.

For example, do you
end up at the starting altitude in all of the cases you discussed related
to fighter evasive techniques?

In the classic BR, used for training purposes, you want to end up at the
starting altitude and the entry airspeed after meeting specific parameters
at different points through the roll. You do this by playing the g and the
various control pressures through the roll.
In the fighter role however, you are maneuvering the airplane in a 3
dimensional arena in relation to the true motion of another aircraft in that
arena. Your altitude and airspeed, and even the arc of a barrel roll is
referenced only to what you need in the way of positioning in relationship
to that other aircraft. These rolls are usually done quite fast and very
tightly as a corkscrew roll.


If you lose a lot of altitude
during the roll, then I can see being able to hold less than 1g through
most of the maneuver. I don't see how this is possible for any roll that
could be superimposed on a cylinder (the barrel) with the ending point
being at the same radial location as the starting point - that is if you
start at the bottom of the barrel you end at the bottom of the barrel. I
couldn't visualize all of your permutations on the roll to know if this
was the case or not.

If you didn't vary the g through the roll, you are right; you couldn't
maintain a steady position on the cylinder. The only way to do it is to ease
off the g on the way up to inverted, then re-apply the g on the back side.
If you held the same g through the roll, you would cork screw through the
roll. It would still be a barrel roll however. The cork screw shape of the
roll dosen't change the fact that the airplane is still traveling through 3
dimensions using a 3 dimensional maneuver. It just dosen't look as nice as
the big wide classic training barrel roll :-))

Matt Whiting wrote:

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.

Fair enough. I interpreted the description to mean that the barrel roll
could be up to 3.5 Gs or as low as 0.5g, but I assumed constant
acceleration, not varying.

And for the record, I know absolutely nothing about aerobatics. Someday I
certainly would enjoy taking some lessons, but for now I am all ears.

--
Peter

Visual aid... take a model airplane, hold it between your
finger tips on the nose and tail. Rotate it so it turns on
the fuselage. That's a plain roll or aileron roll. When
you get inverted you use forward stick to keep the nose up,
you get negative Gs inverted.
Hold the model by the cabin area and rotate it to a nose up
attitude of 30 degrees and then rotate it so the plane
rotates about the tilted vertical axis... that's a snap roll
or horizontal spin.

Hold the model by the tail with your right hand and hold
your left arm straight out. move the model around your left
arm so it is wings level when you start with both arms
straight ahead, the airplane wings are knife-edge when above
your arm, inverted when your right hand is to the left of
the left arm, etc. That is a barrel roll.



--
James H. Macklin
ATP,CFI,A&P

"Dudley Henriques" wrote in message
nk.net...
|
| "Bob Moore" wrote in message
| . 121...
| 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
|
| I see.
|
| Well, I have been using Bill Kershner myself for as many
years as he's been
| publishing and am in complete agreement with both his and
the service ways
| of defining barrel rolls. I think what you and I have
going here is a matter
| of definition within the definition so to speak, which
admittidedly can be a
| bit confusing. :-))
| All this means is that we're saying the same things only
defining it
| somewhat differently. I'm simply defining it a bit deeper
by shrinking the
| area in which the roll can be performed. Everything else
is the same.
| Let me put it this way. Both Kershner and the Navy have
chosen a specific
| set of parameters to define the execution of a barrel
roll. These parameters
| are fine, and are in use on a daily basis by most
competent instructors
| teaching aerobatics.
|
| What I'm saying is that the same identical 3 dimensional
roll described by
| both Kershner and the Navy can be performed to much
tighter parameters.
| The main point of defining a barrel roll isn't the size of
the roll, or the
| points chosen by any particular reference source to define
how the roll
| should be done, but the fact that the roll takes the
airplane through 3
| dimensional space using a 3 dimensional maneuver. This is
a unique maneuver
| that we define as a barrel roll. It's a barrel roll if
it's tight, and its a
| barrel roll if its flown to the specifications used by
either Kershner or
| the Navy.
| All Kershner and the Navy have done is to choose one
specific set of
| parameters that define a barrel roll for training
purposes. What they have
| done is choose parameters to produce a maximum training
result, and they are
| correct to have done it this way. As I have said, I also
have taught barrel
| rolls this way.
| I'm also saying however, that any roll flown through three
dimensional space
| using a three dimensional maneuver can be defined as a
barrel roll. In BFM
| and ACM, there are other terms used for these rolls. They
can be called
| "displacement or lag rolls" for example, where an attacker
will go out of
| plane and perform a 3 dimensional roll opposite the
defender's flight path
| to regain angle off and maintain nose to tail separation
to avoid an
| overshoot in the plane of the defender. The main point is
that if this roll
| goes through 3 dimensions, its a barrel roll.
| If you want a Navy source to confirm all this , simply
copy what I've said
| here and drop it in an email to either TPS (the test pilot
school at Pax),
| or out to Top Gun at Miramar. I believe they will verify
for you if need be.
| Dudley Henriques
|
|