Gyroscopic Precession

[Caldera]

Hey All,

Let me first say that I am not a pilot, nor have any measurable experience in piloting a propeller driven aircraft.  But in my learning to fly the P-47 there was a few topics that I strove to understand.  Once such topic was gyroscopic precession and its effect on aerobatic maneuvers.

One of my many searches lead me to this video, which is excellent in explaining the effect.  Also the speaker is a well accomplished aerobatic pilot with many instructional videos. (check out his other links because they are awesome)

From my understanding a clockwise rotating propeller should produce precession in the following ways:

Down elevator --> nose left

Up elevator     --> nose right

Left rudder     --> nose up

Right rudder   --> nose down

If this is not correct, please correct me.

 

However, the DCS P-47 does not seem to behave this way.  By mashing the rudder hard right produces nose down and nose right.  By mashing the rudder hard left produces nose down and nose left.

Where in reality ...

 

I realize that the P-47's purpose is not aerobatics, but shouldn't a full aft stick in combination with hard left rudder produce an accelerated stall, a right hand rotation snap roll and departure from flight almost instantly?

I have watched a few interviews (YouTube) by WW2 aces who said that they performed that very same maneuver to escape being shot down and one who claimed that he shot down a ME-262 by a lucky shot during one such maneuver.

 

Anyone care to straighten me out here?

Caldera

 

Edited June 15, 2023 by Caldera

[Ala13_ManOWar]

In reality you also have wings with a lift vector, that's perhaps why you don't completely see the absolute same effect.

I'd say "to my knowledge…", but I can't really recall all the stuff. What I recall is I always liked better left airport patterns before right ones because those were more comfortable to fly, I guess your nose high attitude instead of having to pull the yoke on top of the right turn is what is more comfortable. C152 of course, nothing that fancy. Anyhow remember you also have adverse yaw in turns, because of the wings and ailerons aerodynamics, that can also change your perception. But yes, those, and a lot more indeed, are the basic effects you have with a turning propeller in front of you. Haven't tried P-47 seeking for those effects in particular and it's correctness, they should be there and should be right. If something's off by mistake it should be addressed of course. Never noticed weird things. Don't you have a video or something to show?

[Caldera]

I have attached a short track. 

The response to hard left or right rudder input is how I described above.  I tried to attain level flight each time before the maneuver.

18 hours ago, Ala13_ManOWar said:

In reality you also have wings with a lift vector, that's perhaps why you don't completely see the absolute same effect.

I'd say "to my knowledge…", but I can't really recall all the stuff. What I recall is I always liked better left airport patterns before right ones because those were more comfortable to fly, I guess your nose high attitude instead of having to pull the yoke on top of the right turn is what is more comfortable. C152 of course, nothing that fancy. Anyhow remember you also have adverse yaw in turns, because of the wings and ailerons aerodynamics, that can also change your perception. But yes, those, and a lot more indeed, are the basic effects you have with a turning propeller in front of you. Haven't tried P-47 seeking for those effects in particular and it's correctness, they should be there and should be right. If something's off by mistake it should be addressed of course. Never noticed weird things. Don't you have a video or something to show?

Yes, I get the "left turning, roll tendencies and I suppose the few other effects" at least a from theory, not from practice.  To me this is different.  But it only seems to me that a hard and sudden yaw movement should produce some noticeable precession.  To my inexperience, I can not notice any because the effect seems almost the same to left or to the right. 

Gyroscopic precession makes possible some impossible seeming aerobatic maneuvers.

Which aircraft would you usually fly in DCS?

Caldera

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