an exercise for sim pilots -- a 1 G roll

In article ,
says...
Duncan writes:

Hmmm I thought MSFS had a reset key combination.

It is bad form to use any type of reset in simulation. If you have to
reset it, you've failed.

Do you re-install after a crash or do you pretend you're dead
and not use it anymore?

I usually restart the sim, depending on the aircraft. Add-ons don't
always restart gracefully.

OK... so going back to your earlier comments:
Breaking both wings off in the simulator is also a very safe maneuver
isn't it?

No, it causes the aircraft to crash.

Any injuries?

All aboard are lost.

How much did it cost for the new plane?

It depends on the aircraft, of course.

Are you a troll?

Why don't you head down to your local flight school and do a $100 trial
flight? You'll get a logbook and get to make your first entry in it.
You'll get to fly a real plane, hands on.

Yer a troll aren't ya

--
Duncan

On Jan 5, 6:51 am, Mxsmanic wrote:
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.


Ah, but if you are capable of the task, you can apply some classical
physics to the information provided in the archive and do the analysis
yourself.

If you are not capable of the analytical physics you might have to do
experimental physics. In your case if you have the skills those can be
gamed.

Or, remain ignorant, and wrong.

Again.





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.

--
Transpose mxsmanic and gmail to reach me by e-mail.

The physics of this 1 g roll are nicely demonstrated at

http://www.stanford.edu/~siegman/one_g_roll.html


The question I had asked in the first posting seems to have been
answered by Kyle.


This was almost as much fun as the airplane on a treadmill thread --
thanks everyone.


Now there's an idea. Let's design a treadmill that follows the 1 g roll
path and sell it to Disney! It wouldn't be much fun for the kids riding
it, would it? ( I have one year from first public disclosure to file a
patent application, right?)

On Jan 5, 9:05 am, "Tony" wrote:
On Jan 5, 6:51 am, Mxsmanic wrote:

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.Ah, but if you are capable of the task, you can apply some classical
physics to the information provided in the archive and do the analysis
yourself.

If you are not capable of the analytical physics you might have to do
experimental physics. In your case if you have the skills those can be
gamed.

Or, remain ignorant, and wrong.

Again.





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.

--
Transpose mxsmanic and gmail to reach me by e-mail.- Hide quoted text -- Show quoted text -

"T o d d P a t t i s t" wrote in message

you can't change altitude without a
change in G force, that's true, but only if you start from
level flight. If you start from a climb, it's no problem.

I believe you could decrease your altitude while banking and maintain 1G
from level flight.

If you roll the aircraft without a change in altitude, the magnitude
of the G force can be held constant.


Even this is only partly true - you do need to impose
acceleration forces on the aircraft and pilot to produce the
torque required to start and finish the axial rotation of
the aircraft as it makes a roll.

Okay, but then...

Unlike the impossible roll question originally asked, the
loop problem is sort of interesting. Let's assume the
pilot has to feel a steady unchanging 1G and look at what
has to happen in the level flight start case. Initially he
feels that 1G straight down. Now we want to start a loop.
The 1G vector has to tilt back, so we have to reduce the
straight down force of gravity by allowing the aircraft to
descend.

Tilting the 1G vector back, the nose comes up. This requires rotational
acceleration just like the roll, only on a different axis. Sauce for
the goose and all.

You just can't easily raise the nose and
make the aircraft descend.

Reduce engine power, the aircraft descends. Raise the nose, the
aircraft ascends (at least in the short term). Do them both so that the
two cancel out, and you've achieved your goal.

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

click on the url for the physics analysis. Newton's laws (or
approximations) says it can be done, as the analysis done at Stanford
suggests.

This is the neat part -- the sim flyers can actually do this thing and
claim to feel the same physical sensations real pilots do!

For those who dispute the physics -- please indicate where the url is
wrong.

On Jan 5, 10:14 am, "Steve Foley" wrote:
"T o d d P a t t i s t" wrote in message

you can't change altitude without a
change in G force, that's true, but only if you start from
level flight. If you start from a climb, it's no problem.I believe you could decrease your altitude while banking and maintain 1G
from level flight.

All who disagree with the physical analysis URL I provided are
encouraged to show where that analysis is incorrect. Waving hands and
shouting doesn't do much to change Newton's Laws, and the action
proposed keeps it out of relativistic physics.

Apply Newton correctly to the problem -- as I think has been done in
the reference I cited and elsewhere -- and you should come to the same
conclusion.

Kyle's very practical suggestion of being in a climb (and I can show
you how to go from straight and level into a climb maintaining one g
into the seat) at the start of the roll offered a solution I did not
see for overcoming the final downward velocity the flight path would
have taken had one started from straight and level.

People who understand the physics can understand how neat a problem and
solution this is.

Most of the number crunching seems to show in the airplane will be
flying a psudo barrel roll with an 80 foot diameter. That's really
yanking on the controls.





On Jan 5, 11:21 am, Jose wrote:
If you roll the aircraft without a change in altitude, the magnitude
of the G force can be held constant.

Even this is only partly true - you do need to impose
acceleration forces on the aircraft and pilot to produce the
torque required to start and finish the axial rotation of
the aircraft as it makes a roll.Okay, but then...

Unlike the impossible roll question originally asked, the
loop problem is sort of interesting. Let's assume the
pilot has to feel a steady unchanging 1G and look at what
has to happen in the level flight start case. Initially he
feels that 1G straight down. Now we want to start a loop.
The 1G vector has to tilt back, so we have to reduce the
straight down force of gravity by allowing the aircraft to
descend.Tilting the 1G vector back, the nose comes up. This requires rotational
acceleration just like the roll, only on a different axis. Sauce for
the goose and all.

You just can't easily raise the nose and
make the aircraft descend.Reduce engine power, the aircraft descends. Raise the nose, the
aircraft ascends (at least in the short term). Do them both so that the
two cancel out, and you've achieved your goal.

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

I made a mistatement in my prior post. I do not know how to get into a
30 degree climb from straight and level without experiencing a change
in preceived G forces.

Duncan writes:

Are you a troll?

No.

Why don't you head down to your local flight school and do a $100 trial
flight?

In part because $100 is almost what I make in a week. In part because
there are no local schools. In part because I have no time or
transportation to get to a flight school. And in part because, even
if I enjoyed the flight, I have no resources to pursue any type of
real-world flying.

You'll get a logbook and get to make your first entry in it.

Wow. Do I get small appliances after logging a certain number of
hours?

You'll get to fly a real plane, hands on.

Wow.

Actually, I'd much rather have time on some full-motion sims.

--
Transpose mxsmanic and gmail to reach me by e-mail.

Tony writes:

Ah, but if you are capable of the task, you can apply some classical
physics to the information provided in the archive and do the analysis
yourself.

Acceleration is a change in velocity. Climbing from the ground (or
from any constant altitude) is a change in vertical velocity (since
the initial rate of climb is zero). Therefore climbing involves
acceleration. G forces are nothing more than acceleration. Therefore
climbing changes G forces. QED.

If you are not capable of the analytical physics you might have to do
experimental physics.

Nothing that complicated is required. See above.

--
Transpose mxsmanic and gmail to reach me by e-mail.