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Old January 5th 07, 04:45 PM posted to rec.aviation.piloting
Tony
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Posts: 312
Default an exercise for sim pilots -- a 1 G roll


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
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