an exercise for sim pilots -- a 1 G roll

You're on the right track. I'd guess my entry angle is 20-30 degrees nose
up and I typically end the roll between level and 10 degrees nose down.

KB

"Tony" wrote in message
oups.com...
Kyle, if the roll is completed in 4 seconds, that means the airplane
will be 'falling' about 75 knots after 360 degrees. Doesn't that mean
if you start the roll with a vertical velocity of 75 kts you'll come
out with a zero vertical speed component? With a 150 kt airspeed, that
means starting the roll with a 30 degree climb.

Interesting idea!

Thanks



On Jan 2, 10:21 pm, "Kyle Boatright" wrote:
"Tony" wrote in
ooglegroups.com...

The notion of starting in a climb solves a lot of problems, I had not
thought of that,

And if you start S&L and fast, you can enter the climb while in a
controlled deceleration, too, keeping that 1 G component down relative
to the seat, too.

How fast do you have to enter, and how long does the roll take?

Thanks!Anywhere from 100 to 170 knots. The roll probably takes 4-5
seconds, but I
don't have the skill level to perform a roll and time it simultaneously.

KB

On Jan 4, 3:38 pm, Mxsmanic wrote:
Tony writes:
Duncan, the 'roll' I'm talking about would NOT be felt in the seat of
your pants -- it would be one G down into the seat throught the entire
roll. Kyle's observations in this thread are more on target. Done
correctly in an airplane it would feel exactly the same as it would if
it was flown while gaming it on a sim in your home office.Not quite. You wouldn't be at exactly 1 G throughout the roll, so at
times you'd feel as though you were rising or falling (though not
necessarily in a dramatic way).


You are incorrect.

There is a flight path, taking into account roll, pitch, yah, and
thrust, that will result in a complete roll with an g meter indicating
1 G into the seat. Elsewhere in the thread someone indicated a solution
for the last part of the problem, namely if entered from straight and
level the airplane would be going down at about 75 kts at the end of
the roll.

The question I asked at the start wasn't if the flight path exists --
it does -- but rather, is there an airplane that has the control
authority to fly it.

My real life airplane, an M20, may not be flown at more than 30 degrees
pitch or 60 degrees bank, but those kinds of limitations do not apply
to someone who games on a flight simulator, or who has a suitably
certified airplane. My OP request was to have someone who is skilled in
simulated flight see if their simulated airplane had the control
authority to fly that flight path.







onogal balls ,

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My real life airplane, an M20, may not be flown at more than 30 degrees
pitch or 60 degrees bank

Is this a regulatory limitation, or a control surface (laws of physics)
limitation?

Jose
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On Jan 4, 8:29 pm, Jose wrote:
My real life airplane, an M20, may not be flown at more than 30 degrees
pitch or 60 degrees bankIs this a regulatory limitation, or a control surface (laws of physics)
limitation?

Jose

It's a certification limitation, Jose. A skilled pilot can roll and
loop maintaining reasonable positive Gs -- even I can, in suitable
airplanes -- but FAA says don't do it.

I did have a friend who did a not too careful loop in his Mooney, and
on the way down he got to redline airspeed really quickly: for a spam
can, the Mooney class is very very clean and slippery. That big spar
that runs through the cabin was really useful to him on the pullout.
I'll bet they are a real bear in a spiral -- go from start to wingover
in a wink.

It's a certification limitation, Jose.

Ok, then your airplane may well have the control authority to do it, you
just (wisely) don't want to find out the hard way. However, when you
asked:

The question I asked at the start wasn't if the flight path exists --
it does -- but rather, is there an airplane that has the control
authority to fly it.

it implies that you didn't believe spam cans could. Now I understand
the real question is whether the sim of such spam cans can, by which you
may infer that the real one can (or that the sim is inaccurate - I don't
know how you'd pick between them)

Jose
--
He who laughs, lasts.
for Email, make the obvious change in the address.

Jose, I suspect the physics the sims use for coordinated flight at
least is pretty reasonable. Since stall characteritics are a function
of rigging (I doubt two Mooneys with their laminar flow wings stall the
same) I'm not sure how well a sim game does that.

If a credible sim jock claimed his G meter stayed fixed at 1 when he
flew his 172, F16 -- or maybe his Harrier -- though a roll, I'd be
willing to say QED.



On Jan 4, 10:15 pm, Jose wrote:
It's a certification limitation, Jose.Ok, then your airplane may well have the control authority to do it, you
just (wisely) don't want to find out the hard way. However, when you
asked:

The question I asked at the start wasn't if the flight path exists --
it does -- but rather, is there an airplane that has the control
authority to fly it.it implies that you didn't believe spam cans could. Now I understand
the real question is whether the sim of such spam cans can, by which you
may infer that the real one can (or that the sim is inaccurate - I don't
know how you'd pick between them)

Jose
--
He who laughs, lasts.
for Email, make the obvious change in the address.

Tony writes:

There is a flight path, taking into account roll, pitch, yah, and
thrust, that will result in a complete roll with an g meter indicating
1 G into the seat.

No, there is not. You cannot change altitude without a change in G.
Indeed, any acceleration of the aircraft, in any direction, will
change the G force. You can keep it normal to the pilot's seat in
many cases, but you cannot hold its magnitude constant.

My real life airplane, an M20, may not be flown at more than 30 degrees
pitch or 60 degrees bank, but those kinds of limitations do not apply
to someone who games on a flight simulator, or who has a suitably
certified airplane.

In theory, any aircraft can do a barrel roll, as long as the net
acceleration vector is kept downward.

My OP request was to have someone who is skilled in
simulated flight see if their simulated airplane had the control
authority to fly that flight path.

I was able to do it in the default Cessna on MSFS, not very neatly but
with the G force always positive. It's supposedly an extremely safe
maneuver as long as that number stays positive.

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Tony writes:

If a credible sim jock claimed his G meter stayed fixed at 1 when he
flew his 172, F16 -- or maybe his Harrier -- though a roll, I'd be
willing to say QED.

It cannot stay fixed at 1.

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On Jan 5, 4:58 am, Mxsmanic wrote:
Tony writes:
There is a flight path, taking into account roll, pitch, yah, and
thrust, that will result in a complete roll with an g meter indicating
1 G into the seat.


No, there is not. You cannot change altitude without a change in G.
Indeed, any acceleration of the aircraft, in any direction, will
change the G force. You can keep it normal to the pilot's seat in
many cases, but you cannot hold its magnitude constant.

In fact you are wrong. You may wish to look in the archives of this
newsgroup for the proof.

You can demostrate at least the early part of such a roll by starting a
coordinated turn and adding sufficient forward pressure on the yoke to
remove the additional G's a level turn would induce. One suce flight
path requires you to accelerate downward at 1 G.

This is actually a fairly simple classical physics problem -- at least
one poster solved it using a spread sheet.

You are quite correct, however, in stating most airplanes can be flown
in a loop or a roll safely with positive G forces, but nealy all
general aviation aircraft certified in the United States are not
certified for such flight paths.

I do think you didn't quite say what you meant when you stated you
cannot change altitude without changing G. What g force would you
expect it you were climbing at 500 feet a minute?





My real life airplane, an M20, may not be flown at more than 30 degrees
pitch or 60 degrees bank, but those kinds of limitations do not apply
to someone who games on a flight simulator, or who has a suitably
certified airplane.In theory, any aircraft can do a barrel roll, as long as the net
acceleration vector is kept downward.

My OP request was to have someone who is skilled in
simulated flight see if their simulated airplane had the control
authority to fly that flight path.I was able to do it in the default Cessna on MSFS, not very neatly but
with the G force always positive. It's supposedly an extremely safe
maneuver as long as that number stays positive.

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Tony writes:

In fact you are wrong. You may wish to look in the archives of this
newsgroup for the proof.

The archives of this newsgroup are proof of nothing.

You cannot change altitude without acceleration, and that changes G
force. You cannot execute any type of roll that involves any change
in altitude without a change in G force. This is basic physics.

If you roll the aircraft without a change in altitude, the magnitude
of the G force can be held constant. However, in that case, you
cannot keep the vector pointed in the same direction.

If you want positive G through the normal vector when moving through
the inverted portion of a roll, you _must_ accelerate downward at at
least one G at some point, otherwise gravity will reduce G to zero and
make it negative. When the aircraft is inverted, gravity produces
-1.0 G of acceleration on the pilot. The only way to counter this is
to accelerate downward at at least 1 G.

I do think you didn't quite say what you meant when you stated you
cannot change altitude without changing G. What g force would you
expect it you were climbing at 500 feet a minute?

None, but you would experience greater than 1 G as you started the
climb, and less than 1 G as you ended it. You have to accelerate
upward to start a climb and downward to stop it. You cannot
accelerate without inducing G forces. The same is true in turns.

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