barrel roll in 172

Don't encourage that type of behavior with a yes. If he had to ask, he is

I'm slightly disappointed by how quickly you've assumed my complete
brainlessness. Yes I know what FARs say, and what POH says, and no, I'm
not going to read this newsgroup and go break my neck the next morning.
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.


Andrey

Andrey Serbinenko schrieb:

I'm slightly disappointed by how quickly you've assumed my complete
brainlessness.

If this surprizes you, then you don't read this group often.

Stefan

A properly done mild acro maneuver is well within the limits
of even a normal category airplane [3.8G], but it is easy to
botch a maneuver and then the recovery can require much
higher forces. They only test using qualified and competent
pilots and they only test for maneuvers they intend to
certify the aircraft to do.
Some airplanes may be certified for "flick" maneuvers or
accelerated maneuvers entered at higher speeds, such as
snap rolls. Some aircraft are approved for unlimited
maneuvers and they sometimes break.

see http://www.faa.gov/regulations_polic...a_regulations/
§ 23.151 Acrobatic maneuvers.
Each acrobatic and utility category airplane must be able to
perform safely the acrobatic maneuvers for which
certification is requested. Safe entry speeds for these
maneuvers must be determined.


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§ 23.221 Spinning.
(a) Normal category airplanes. A single-engine, normal
category airplane must be able to recover from a one-turn
spin or a three-second spin, whichever takes longer, in not
more than one additional turn after initiation of the first
control action for recovery, or demonstrate compliance with
the optional spin resistant requirements of this section.

(1) The following apply to one turn or three second spins:

(i) For both the flaps-retracted and flaps-extended
conditions, the applicable airspeed limit and positive limit
maneuvering load factor must not be exceeded;

(ii) No control forces or characteristic encountered during
the spin or recovery may adversely affect prompt recovery;

(iii) It must be impossible to obtain unrecoverable spins
with any use of the flight or engine power controls either
at the entry into or during the spin; and

(iv) For the flaps-extended condition, the flaps may be
retracted during the recovery but not before rotation has
ceased.

(2) At the applicant's option, the airplane may be
demonstrated to be spin resistant by the following:

(i) During the stall maneuver contained in §23.201, the
pitch control must be pulled back and held against the stop.
Then, using ailerons and rudders in the proper direction, it
must be possible to maintain wings-level flight within 15
degrees of bank and to roll the airplane from a 30 degree
bank in one direction to a 30 degree bank in the other
direction;

(ii) Reduce the airplane speed using pitch control at a rate
of approximately one knot per second until the pitch control
reaches the stop; then, with the pitch control pulled back
and held against the stop, apply full rudder control in a
manner to promote spin entry for a period of seven seconds
or through a 360 degree heading change, whichever occurs
first. If the 360 degree heading change is reached first, it
must have taken no fewer than four seconds. This maneuver
must be performed first with the ailerons in the neutral
position, and then with the ailerons deflected opposite the
direction of turn in the most adverse manner. Power and
airplane configuration must be set in accordance with
§23.201(e) without change during the maneuver. At the end of
seven seconds or a 360 degree heading change, the airplane
must respond immediately and normally to primary flight
controls applied to regain coordinated, unstalled flight
without reversal of control effect and without exceeding the
temporary control forces specified by §23.143(c); and

(iii) Compliance with §§23.201 and 23.203 must be
demonstrated with the airplane in uncoordinated flight,
corresponding to one ball width displacement on a slip-skid
indicator, unless one ball width displacement cannot be
obtained with full rudder, in which case the demonstration
must be with full rudder applied.

(b) Utility category airplanes. A utility category airplane
must meet the requirements of paragraph (a) of this section.
In addition, the requirements of paragraph (c) of this
section and §23.807(b)(7) must be met if approval for
spinning is requested.

(c) Acrobatic category airplanes. An acrobatic category
airplane must meet the spin requirements of paragraph (a) of
this section and §23.807(b)(6). In addition, the following
requirements must be met in each configuration for which
approval for spinning is requested:

(1) The airplane must recover from any point in a spin up to
and including six turns, or any greater number of turns for
which certification is requested, in not more than one and
one-half additional turns after initiation of the first
control action for recovery. However, beyond three turns,
the spin may be discontinued if spiral characteristics
appear.

(2) The applicable airspeed limits and limit maneuvering
load factors must not be exceeded. For flaps-extended
configurations for which approval is requested, the flaps
must not be retracted during the recovery.

(3) It must be impossible to obtain unrecoverable spins with
any use of the flight or engine power controls either at the
entry into or during the spin.

(4) There must be no characteristics during the spin (such
as excessive rates of rotation or extreme oscillatory
motion) that might prevent a successful recovery due to
disorientation or incapacitation of the pilot.

[Doc. No. 27807, 61 FR 5191, Feb. 9, 1996]

"Andrey Serbinenko" wrote in
message ...
| Don't encourage that type of behavior with a yes. If he
had to ask, he is
|
| I'm slightly disappointed by how quickly you've assumed my
complete
| brainlessness. Yes I know what FARs say, and what POH
says, and no, I'm
| not going to read this newsgroup and go break my neck the
next morning.
| 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.
|
|
| Andrey
|

Andrey Serbinenko wrote

I'm slightly disappointed by how quickly you've assumed my complete
brainlessness. Yes I know what FARs say, and what POH says, and no,
I'm not going to read this newsgroup and go break my neck the next
morning. 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.

First Andrey, you will probably find much disagreement on this group
as to what actually constitues a "barrell roll". If conducted as
normally accepted in the aerobatic community, it consists of a
combination loop and roll which at most, places about 3g's on the
airframe. The g loading is not the problem in the utility category C-
172, its lack of power to complete the loop portion is what makes it
particularly difficult.
Below, I have copied a description of a "barrell roll". This may or may
not be the maneuver that you have in mind. It would obviously be much
easier in one of the higher powered 172s than in the O-300, 145hp
powered version that I fly. :-)

After reading the following, you might find that you really didn't mean
to say "barrell roll". :-) BTW the two following descriptions are how
I was taught to perform the "barrell roll" in Navy flight training. :-)

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.

And another description from Kershner's Flight Instructor's Manual:

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,
seeing
nothing 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.

Why didn't you ask that in the original question then?


"Andrey Serbinenko" wrote in message
...
Don't encourage that type of behavior with a yes. If he had to ask, he
is

I'm slightly disappointed by how quickly you've assumed my complete
brainlessness. Yes I know what FARs say, and what POH says, and no, I'm
not going to read this newsgroup and go break my neck the next morning.
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.


Andrey

Well, I thought that I worded the question clearly enough. What I did not
realize was that the video that I'm told has been circulated here a short while
ago would make the question look like someone is about to do something rather
stupid in his 172.


Barney Rubble wrote:
Why didn't you ask that in the original question then?


"Andrey Serbinenko" wrote in message
...
Don't encourage that type of behavior with a yes. If he had to ask, he
is

I'm slightly disappointed by how quickly you've assumed my complete
brainlessness. Yes I know what FARs say, and what POH says, and no, I'm
not going to read this newsgroup and go break my neck the next morning.
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.


Andrey

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

I'm slightly disappointed by how quickly you've assumed my complete
brainlessness.

The reaction is probably due to a freshly minted private pilot who
recently posted a link to a video of him and his instructor doing a
roll (or was it a loop?) in a C-150.

Publishing such blatant disregard for regulations in a worldwide
public forum casts a bad light on all airmen, and is guaranteed to
receive the wrath of the readership of this newsgroup.

Larry Dighera schrieb:

The reaction is probably due to a freshly minted private pilot who
recently posted a link to a video of him and his instructor doing a
roll (or was it a loop?) in a C-150.

Probably not. Besides, who tells you it wasn't an aerobat and the
instructor not acro rated?

Stefan

On Thu, 20 Jul 2006 20:08:55 +0200, Stefan
wrote in : :

Besides, who tells you it wasn't an aerobat and the
instructor not acro rated?


From: "NW_PILOT"
Newsgroups:

rec.aviation.aerobatics,rec.aviation.ifr,rec.aviat ion.owning,rec.aviation.piloting,rec.aviation.stud ent
Subject: Rolling a Non Aerobat 150
Date: Wed, 27 Apr 2005 08:48:36 -0700
Message-ID:
NNTP-Posting-Host: 67.168.204.123

This video was taken by my instructor with my digital cam so its
poor quality, It's my first unassissted [sic] roll
http://www.warflying.net/roll.avi

You haven't been reading this newsgroup very long.

Larry Dighera schrieb:

Besides, who tells you it wasn't an aerobat and the
instructor not acro rated?

Subject: Rolling a Non Aerobat 150

ok.

poor quality, It's my first unassissted [sic] roll

Whatever "unassisted" means. But I agree that an instructor taking a
video most probably doesn't qualify as an assistant.

You haven't been reading this newsgroup very long.

I read it occasionally. And even if I do, I don't save everything to my
brain.

Stefan