Looping during a commercial flight

"LordAvalon" wrote in message
om...
"Rob Stokes" wrote in message
...
I have no proof, but looping an airliner without the passengers being
aware
is not possible. Perhaps visually the passengers wouldn't notice, but
balance wise / spatially they certainly would. I have heard from
many
sources that the last airliner to be taken for a loop was a B-707
after
which many of the A/C components shifted up to an inch, the pilot was
immediately disciplined! other similar instances have occurred on
Russian
airliners by Ex-military pilots shortly after the war. At the
Goodwood
Festival Of Speed (England) this year, there was a 'semi' aerobatic
display
by a south African jumbo (consisting of very low steep turns)

Thanks for your input.
I am not an expert in flying terms so maybe it is not exactly
"looping" i heard of. The plane would drop to the left for exemple
with his longitudinal axis straight and acquire vertical speed. Then
the pilot would shift the stick right very slowly to convert this
vertical speed in a centrifugal vector. This is supposed to recreate
the same phenomemom as a pail full of water tied to a rope you turn
fast. So, as this theory goes, after the initial banking the figure
would make the passengers feel only a moderate or no increase in their
weight, the force being directed towards the floor of the plane. Since
the long axis of the plane is not disturbed no other noticeable
effects should appear...

But if it is unheard of, it may well be purely theorical or simply an
urban legend!

No. It's possible, but I haven't heard of it being done successfully in
the pure vertical plane as in a straight positive g loop. More likely in
a three dimensional maneuver like a barrel roll. The energy or Ps bleed
for a big jet is tremendous in the vertical plane, and an entry airspeed
required to get everything up and around the topside apex would be
considerable to say the least. Considering the huge drag index against
what would have to be at least a 4 positive g pull to even have a chance
at an inverted apex, the entry speed would be prohibitive for safety I
think; considering the aerodynamic factors and the requirement for
positive g at the top for the scavenger pumps. In other words, floating
it through the top unloaded is eliminated from the equation because of
the pumps if nothing else. The engines oil system requires positive g to
operate. Unloading would deny the engines oil and the result at a high
percent RPM or EPR could lose you the engines. The result of that would
be a negative nose rate and developing vertical descent while inverted
that could really spoil your afternoon :-)
In a normal loop, you ease off the positive g at the top to round it off
and keep the AOA in limits. In a big jet, this could really be a
problem.
A three dimensional roll (barrel roll) is possible for a big jet, and
has been done, even in the prototype 707. You are right about keeping
the g positive all the way around. Both myself and several other
demonstration pilots at one time or another have barreled airplanes with
a glass of water on the instrument glare shield. I have done it in a D18
Twin Beech several times and Bob Hoover has done it in a Shrike
Commander......many times. :-)
In barrel rolling a large airplane, you can keep the stress at a minimum
and perform the maneuver in a wide low positive g profile that is kept
positive all the way around. Because it's FLOWN around the circle rather
than a pure roll on the longitudinal axis, the deep dishout on the back
side that would be the result of an aileron roll can be eliminated by
the trade off in altitude on the upside against the backside recovery.
Basically, even though I'm sure a pure loop has been done by heavy jets
at one time or another, I would classify the maneuver as extremely risky
at best, and totally unwise to attempt. But as I said....I'm sure
somebody managed to get the entry speed necessary to do it regardless of
the risk, and somehow managed to pull it around without shedding all the
critical parts in the process. But I wouldn't want to be the next pilot
to fly that airplane :-)
Dudley Henriques
International Fighter Pilots Fellowship
Flight Instructor/Aerobatics/Retired

"Dudley Henriques" wrote in message link.net...
"LordAvalon" wrote in message
om...
"Rob Stokes" wrote in message
...
I have no proof, but looping an airliner without the passengers being
aware
is not possible. Perhaps visually the passengers wouldn't notice, but
balance wise / spatially they certainly would. I have heard from
many
sources that the last airliner to be taken for a loop was a B-707
after
which many of the A/C components shifted up to an inch, the pilot was
immediately disciplined! other similar instances have occurred on
Russian
airliners by Ex-military pilots shortly after the war. At the
Goodwood
Festival Of Speed (England) this year, there was a 'semi' aerobatic
display
by a south African jumbo (consisting of very low steep turns)

Thanks for your input.
I am not an expert in flying terms so maybe it is not exactly
"looping" i heard of. The plane would drop to the left for exemple
with his longitudinal axis straight and acquire vertical speed. Then
the pilot would shift the stick right very slowly to convert this
vertical speed in a centrifugal vector. This is supposed to recreate
the same phenomemom as a pail full of water tied to a rope you turn
fast. So, as this theory goes, after the initial banking the figure
would make the passengers feel only a moderate or no increase in their
weight, the force being directed towards the floor of the plane. Since
the long axis of the plane is not disturbed no other noticeable
effects should appear...

But if it is unheard of, it may well be purely theorical or simply an
urban legend!

No. It's possible, but I haven't heard of it being done successfully in
the pure vertical plane as in a straight positive g loop. More likely in
a three dimensional maneuver like a barrel roll. The energy or Ps bleed
for a big jet is tremendous in the vertical plane, and an entry airspeed
required to get everything up and around the topside apex would be
considerable to say the least. Considering the huge drag index against
what would have to be at least a 4 positive g pull to even have a chance
at an inverted apex, the entry speed would be prohibitive for safety I
think; considering the aerodynamic factors and the requirement for
positive g at the top for the scavenger pumps. In other words, floating
it through the top unloaded is eliminated from the equation because of
the pumps if nothing else. The engines oil system requires positive g to
operate. Unloading would deny the engines oil and the result at a high
percent RPM or EPR could lose you the engines. The result of that would
be a negative nose rate and developing vertical descent while inverted
that could really spoil your afternoon :-)
In a normal loop, you ease off the positive g at the top to round it off
and keep the AOA in limits. In a big jet, this could really be a
problem.
A three dimensional roll (barrel roll) is possible for a big jet, and
has been done, even in the prototype 707. You are right about keeping
the g positive all the way around. Both myself and several other
demonstration pilots at one time or another have barreled airplanes with
a glass of water on the instrument glare shield. I have done it in a D18
Twin Beech several times and Bob Hoover has done it in a Shrike
Commander......many times. :-)
In barrel rolling a large airplane, you can keep the stress at a minimum
and perform the maneuver in a wide low positive g profile that is kept
positive all the way around. Because it's FLOWN around the circle rather
than a pure roll on the longitudinal axis, the deep dishout on the back
side that would be the result of an aileron roll can be eliminated by
the trade off in altitude on the upside against the backside recovery.
Basically, even though I'm sure a pure loop has been done by heavy jets
at one time or another, I would classify the maneuver as extremely risky
at best, and totally unwise to attempt. But as I said....I'm sure
somebody managed to get the entry speed necessary to do it regardless of
the risk, and somehow managed to pull it around without shedding all the
critical parts in the process. But I wouldn't want to be the next pilot
to fly that airplane :-)
Dudley Henriques
International Fighter Pilots Fellowship
Flight Instructor/Aerobatics/Retired

Thanks a lot for your learned answer. What I have heard of is
certainly what you call "barrel rolling". According to the unreliable
"sources", the pilot of a commercial flight would have done this
barrel rolling at night. Nobody in the plane would have noticed it but
an "Aviation Board Inspector(?)" is supposed to have been present and
reported the deed. Which would have led to sanctions against the
author... To be confirmed!

About doing a barrel roll at night with relationship to passengers;
it is possible, and could be done. The passengers, within a closed
environment, would feel the onset of whatever positive g was used by the
pilot to initiate the roll. If the pilot was very good, and kept perfect
control coordination all through the roll, all the passengers would feel
would be the positive g and no side g loads would be felt.
In short, a barrel roll under the conditions you have stated although
possible, would have to be executed perfectly not to alarm passengers
subjected to it at night in a closed cabin. :-)
Dudley Henriques
International Fighter Pilots Fellowship
Flight Instructor/Aerobatics/Retired

"LordAvalon" wrote in message
om...
"Dudley Henriques" wrote in message
link.net...
"LordAvalon" wrote in message
om...
"Rob Stokes" wrote in message
...
I have no proof, but looping an airliner without the passengers
being
aware
is not possible. Perhaps visually the passengers wouldn't notice,
but
balance wise / spatially they certainly would. I have heard from
many
sources that the last airliner to be taken for a loop was a B-707
after
which many of the A/C components shifted up to an inch, the pilot
was
immediately disciplined! other similar instances have occurred on
Russian
airliners by Ex-military pilots shortly after the war. At the
Goodwood
Festival Of Speed (England) this year, there was a 'semi'
aerobatic
display
by a south African jumbo (consisting of very low steep turns)

Thanks for your input.
I am not an expert in flying terms so maybe it is not exactly
"looping" i heard of. The plane would drop to the left for exemple
with his longitudinal axis straight and acquire vertical speed.
Then
the pilot would shift the stick right very slowly to convert this
vertical speed in a centrifugal vector. This is supposed to
recreate
the same phenomemom as a pail full of water tied to a rope you turn
fast. So, as this theory goes, after the initial banking the figure
would make the passengers feel only a moderate or no increase in
their
weight, the force being directed towards the floor of the plane.
Since
the long axis of the plane is not disturbed no other noticeable
effects should appear...

But if it is unheard of, it may well be purely theorical or simply
an
urban legend!

No. It's possible, but I haven't heard of it being done successfully
in
the pure vertical plane as in a straight positive g loop. More likely
in
a three dimensional maneuver like a barrel roll. The energy or Ps
bleed
for a big jet is tremendous in the vertical plane, and an entry
airspeed
required to get everything up and around the topside apex would be
considerable to say the least. Considering the huge drag index
against
what would have to be at least a 4 positive g pull to even have a
chance
at an inverted apex, the entry speed would be prohibitive for safety
I
think; considering the aerodynamic factors and the requirement for
positive g at the top for the scavenger pumps. In other words,
floating
it through the top unloaded is eliminated from the equation because
of
the pumps if nothing else. The engines oil system requires positive g
to
operate. Unloading would deny the engines oil and the result at a
high
percent RPM or EPR could lose you the engines. The result of that
would
be a negative nose rate and developing vertical descent while
inverted
that could really spoil your afternoon :-)
In a normal loop, you ease off the positive g at the top to round it
off
and keep the AOA in limits. In a big jet, this could really be a
problem.
A three dimensional roll (barrel roll) is possible for a big jet, and
has been done, even in the prototype 707. You are right about keeping
the g positive all the way around. Both myself and several other
demonstration pilots at one time or another have barreled airplanes
with
a glass of water on the instrument glare shield. I have done it in a
D18
Twin Beech several times and Bob Hoover has done it in a Shrike
Commander......many times. :-)
In barrel rolling a large airplane, you can keep the stress at a
minimum
and perform the maneuver in a wide low positive g profile that is
kept
positive all the way around. Because it's FLOWN around the circle
rather
than a pure roll on the longitudinal axis, the deep dishout on the
back
side that would be the result of an aileron roll can be eliminated by
the trade off in altitude on the upside against the backside
recovery.
Basically, even though I'm sure a pure loop has been done by heavy
jets
at one time or another, I would classify the maneuver as extremely
risky
at best, and totally unwise to attempt. But as I said....I'm sure
somebody managed to get the entry speed necessary to do it regardless
of
the risk, and somehow managed to pull it around without shedding all
the
critical parts in the process. But I wouldn't want to be the next
pilot
to fly that airplane :-)
Dudley Henriques
International Fighter Pilots Fellowship
Flight Instructor/Aerobatics/Retired

Thanks a lot for your learned answer. What I have heard of is
certainly what you call "barrel rolling". According to the unreliable
"sources", the pilot of a commercial flight would have done this
barrel rolling at night. Nobody in the plane would have noticed it but
an "Aviation Board Inspector(?)" is supposed to have been present and
reported the deed. Which would have led to sanctions against the
author... To be confirmed!

"Dudley Henriques" wrote in message link.net...
About doing a barrel roll at night with relationship to passengers;
it is possible, and could be done. The passengers, within a closed
environment, would feel the onset of whatever positive g was used by the
pilot to initiate the roll.

Dudley,

In the original post, the question asked if this could be done without
the pax noticing *anything* different from normal flight. Most
kerosene queens are flown with very little g loading to keep 'em happy
in back, but I can't barrel without pulling a bit on the entry and
exit. Now, maybe you or Bob can fly a barrel roll without exceeding
1.3-ish g's, but I know that I can't... and the last time I checked,
the grandma back in 23B noticed when the g-meter hit 3+.

Can you fly one with *very* light g-loads on the entry? If so, how do
you get the nose high enough to recover at that g-load without falling
out? Will you show me how to do it????

Thanks,

-Dave Russell
N2S-3

"Dave Russell" wrote in message
om...
"Dudley Henriques" wrote in message
link.net...
About doing a barrel roll at night with relationship to passengers;
it is possible, and could be done. The passengers, within a closed
environment, would feel the onset of whatever positive g was used by
the
pilot to initiate the roll.

Dudley,

In the original post, the question asked if this could be done without
the pax noticing *anything* different from normal flight. Most
kerosene queens are flown with very little g loading to keep 'em happy
in back, but I can't barrel without pulling a bit on the entry and
exit. Now, maybe you or Bob can fly a barrel roll without exceeding
1.3-ish g's, but I know that I can't... and the last time I checked,
the grandma back in 23B noticed when the g-meter hit 3+.

Can you fly one with *very* light g-loads on the entry? If so, how do
you get the nose high enough to recover at that g-load without falling
out? Will you show me how to do it????

Thanks,

-Dave Russell
N2S-3

Hi Dave;

Yeah, I just noticed that reference to "from normal flight" myself. The
answer of course is "yes". The pax would indeed feel the g all though
the roll, but the kicker is that if the pilot was REAL good :-)) the pax
might not realize they were in a roll, and since the g would be on the
+Gz axis, it could be confused with a pullup, or a steep turn.

There's nothing wrong with the description in your post. It's right on!
You're perfectly correct that the pax would feel the g. I thought I had
made that point in the last post I made.
"The passengers, within a closed
environment, would feel the onset of whatever positive g was used by the
pilot to initiate the roll. If the pilot was very good, and kept perfect
control coordination all through the roll, all the passengers would feel
would be the positive g"

I didn't bother to mention the exit g as I thought it would be obvious.

To answer your question about g in the roll; you can execute a barrel
roll as tight or as wide as you want to do it, varying the g used to the
radius demanded by the control inputs. It's notable that in fighters in
ACM, you can execute a very tight loaded roll in 3 dimensions as a
vector roll, or you can initiate with positive g, then unload the
airplane through the top, then reapply positive g on the backside.
I would imagine that anyone trying to fool some pax in the back at night
might make a very subtle nose low to increase to entry airspeed, then
very easily bring it on up through level flight, blending in exactly the
right amount of aileron and elevator needed to get the widest roll
radius they could while keeping the airplane at as low a positive g
possible to keep that radius.
It would be tricky.....but it could be done by the right pilot. I would
add however that the exact heavy jet would be a critical item in this
theoretical equation of fun and games. Too heavy and the drag index
going up the front side might be so great that in order to complete the
roll, you would have to tighten up the roll axis and that would increase
the g. You might get through it, but it wouldn't be the smooth wide roll
needed to fool the gang in back! :-))

Just as an aside to this thing we're discussing in this thread, we used
to sometimes play a trick on the techs working with us on a flight test
project. Every month, they gave out a ride in a T38 to some ground tech
who did a good job with something. We would draw straws to see which one
of us would fly them :-)
The roll rate of the Talon is a bit of something to see at about .9
mach. It's restricted to a partial lateral stick throw to avoid coupling
the airplane, but once in a while since my test work was in coupling
anyway, I'd have some fun with the techs.
All these guys were pretty savvy in aerodynamics and were familiar with
the T38's reputation for a fast aileron throw.
If I got a new tech back there, I'd take him out to the restricted area
and do some basic aerobatics with him (they all liked that :-)
Sooner or later, I'd ask if they wanted to see a max deflect aileron
roll at .9. Invariably the answer was "great....do one!!"
I'd take the airplane out to speed and ask if they were ready. When I
got the answer, I'd jerk the stick quickly to the side laterally about
two inches and return it to level flight again in one quick motion. This
usually bounced their heads off the canopy on the opposite side of the
input :-)
If I was real good with the timing, I usually
got......"WOW".....MAN....THAT was FAST!!!!!" :-)) from the back seat!
Every now and then, I'd get one that I could absolutely convince they
had gone all the way around. I'd bring them back and we would hear about
them telling everybody in sight how "fantastic" the roll rate ACTUALLY
WAS in the T38!! :-)
Naturally, sooner or later someone "clued" them in on it.

Ah, I sure miss the good ole' days!!!! :-))
Dudley

"Dudley Henriques" wrote in message
ink.net...



SNIP

A three dimensional roll (barrel roll) is possible for a big jet, and has
been done, even in the prototype 707. You are right about keeping the g
positive all the way around. Both myself and several other demonstration
pilots at one time or another have barreled airplanes with a glass of
water on the instrument glare shield. I have done it in a D18 Twin Beech
several times and Bob Hoover has done it in a Shrike Commander......many
times. :-)

Hi Mr. H,

I didn't realize you'd performed this feat as well...too cool!

Me, I have trouble sometimes just taking a sip of water from a squeeze
bottle on cross country flights LOL.

I recall seeing film of Mr. Hoover doing this with a golf ball hanging off
the overhead and while POURING a glass of water from a pitcher.

Not a drop of water gets spilled and golf ball never moves (the string is
ram-rod straight) while the horizon is seen through the windscreen revolving
through 360 degrees !!

Amazing control...

Regards,

Jay Beckman
Chandler, AZ
PP-ASEL
Still Nowhere to go but up!

"Jay Beckman" wrote in message
news:K1Kdd.7927$SW3.788@fed1read01...
"Dudley Henriques" wrote in message
ink.net...



SNIP

A three dimensional roll (barrel roll) is possible for a big jet, and
has been done, even in the prototype 707. You are right about keeping
the g positive all the way around. Both myself and several other
demonstration pilots at one time or another have barreled airplanes
with a glass of water on the instrument glare shield. I have done it
in a D18 Twin Beech several times and Bob Hoover has done it in a
Shrike Commander......many times. :-)

Hi Mr. H,

I didn't realize you'd performed this feat as well...too cool!

Me, I have trouble sometimes just taking a sip of water from a squeeze
bottle on cross country flights LOL.

I recall seeing film of Mr. Hoover doing this with a golf ball hanging
off the overhead and while POURING a glass of water from a pitcher.

Not a drop of water gets spilled and golf ball never moves (the string
is ram-rod straight) while the horizon is seen through the windscreen
revolving through 360 degrees !!

Amazing control...

Regards,

Jay Beckman
Chandler, AZ
PP-ASEL
Still Nowhere to go but up!

Hi Jay;

Bob Hoover was one of the first charter members of the International
Fighter Pilots Fellowship and is one of the premier demonstration pilots
in the world.
My little "feat" in the D18 was done more or less as an imitation of
what Bob did in the Shrike just to see if we could do it . In all truth
I should say it took a few tries to get it absolutely right, and I did
come home one day with a wet flightsuit ;-) I would imagine Bob has
managed to get a bit wet once or twice himself on occasion when he
wasn't filming :-))
Dudley

Is there a video you watched him doing this? Where can I see this feat?


"Jay Beckman" wrote in message
news:K1Kdd.7927$SW3.788@fed1read01...
"Dudley Henriques" wrote in message
ink.net...



SNIP

A three dimensional roll (barrel roll) is possible for a big jet, and
has
been done, even in the prototype 707. You are right about keeping the g
positive all the way around. Both myself and several other demonstration
pilots at one time or another have barreled airplanes with a glass of
water on the instrument glare shield. I have done it in a D18 Twin Beech
several times and Bob Hoover has done it in a Shrike Commander......many
times. :-)

Hi Mr. H,

I didn't realize you'd performed this feat as well...too cool!

Me, I have trouble sometimes just taking a sip of water from a squeeze
bottle on cross country flights LOL.

I recall seeing film of Mr. Hoover doing this with a golf ball hanging off
the overhead and while POURING a glass of water from a pitcher.

Not a drop of water gets spilled and golf ball never moves (the string is
ram-rod straight) while the horizon is seen through the windscreen
revolving
through 360 degrees !!

Amazing control...

Regards,

Jay Beckman
Chandler, AZ
PP-ASEL
Still Nowhere to go but up!