1. #1
    Is it true that the Gyroscopic Precession is much more pronounced in this patch? In quick porpoising movements of the a/c my nose doesn't point up and down any more, but nearly sideways, about 45 deg. In tight turns my a/c turns nose down in one direction too much, and too much nose up in the other (depending upon the way the propeler turns, clock-anticlockwise)

    I know that WWI a/c had BIG problems with that, but I expected the newer fighters to be much more effective in eliminating it.I basically cant make a level tight turn if I dont kick in a good amount of rudder.

    Does anyone have knowledge if it so much pronounced in reality like it is simulated here?

    And another thing, this might be the reason so many people complain about wobbling of the a/c.
    Try turning the engine off and the difference is apparent. I haven't got this wobbling problem when I'm flying a P-38 (contra rotating propellers).
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  2. #2
    Viper2005_'s Avatar Senior Member
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    I think it's simulated.

    Later war aircraft should be worse than earlier aircraft because they generally have bigger, heavier props.

    As for correction, you can't buck the laws of physics. The only reasonable solution with WWII technology is to have another prop turning the other way!
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  3. #3
    Of course, I wasn't trying to find solutions to eliminate the problem, all I was asking was if the phenomenon is as prominent IRL as it is in the simulator.

    As for the newer aircraft, from what I've read the gyro precession was less because the rotating masses of the engine where fewer, when compared with the old rotary engines of WWI a/c. Those things had a little less than half their body weight rotating!!

    Thanks for the answer though, not many people are aware of this simple phenomenon that governs all rotating things in our life, from the yo-yo to the bicycle, down to earth itself!
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  4. #4
    The effect is there and I think it's fair to say that the gyroscopic effect may be the reason why planes recover from stalls all by themselves.

    Ta,
    Norris
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  5. #5
    Originally posted by NorrisMcWhirter:
    The effect is there and I think it's fair to say that the gyroscopic effect may be the reason why planes recover from stalls all by themselves.

    Ta,
    Norris
    To be honest Norris, I just am not getting the insta stall recovery you refer to... nor spins - if you are refering to recovery in the incipient spin however then letting go of everything will have the tendancy of letting the a/c sort itself out - after all, your control inputs would tend to be the reason for the stall to occur, especially in an accelerated stall, and relinquishing input would allow the a/c to drop back into an AoA regime whereby it is no longer at the stall stage (tho close) and let it try to trim itself out as all a/c have a tendency to.

    Once in the full spin (which incidentily is actually a very stable form of oscillation and therefore difficult to recover from) I find getting ANY of these fighters out before at least two or three FULL turns very difficult - and that seems to bear much resemblance to real life tales of spins in these a/c.

    Have a little look at these sites:

    http://oea.larc.nasa.gov/PAIS/Concep...echnology.html

    http://www.fcitraining.com/vid_clip9_incipient_spin.htm

    they give excellent descriptions of how what and why spins and stalls differ and recovery methods. And bear in mind the recovery techniques will differ for different airframes.
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  6. #6
    Viper2005_'s Avatar Senior Member
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    If we neglect modern fighters with relaxed static stability, most aeroplanes with acceptable handling characteristics are stable in pitch. They will therefore tend to return to the condition of flight they were trimmed for if left to themselves.

    As it is pretty rare to trim an aircraft for the stall, a lot of the time if you just take your hands off the controls it'll sort itself out for you.

    Stall recovery technique is all about minimising the altitude loss associated with the stall. It is not the only way to recover - just the most efficient.

    In some aircraft, autorotation is a stable condition and recovery requires positive action.

    In others, autorotation is not a stable condition, and the aeroplane will recover all by itself "hands off".

    Spin behaviour tends to be somewhat individual. Different aeroplanes of the same type can be very different.

    Weight and balance also has an extremely powerful effect on stall and spin behaviour.

    <span class="ev_code_RED">God help you if you stall or spin with your CoG aft of the aft limit.</span>

    There be Dragons.
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  7. #7
    The above posts make good points, and as far as your question, the bulk of the gyroscopic effects a pilot must contend with are from the prop itself. The mass, diameter, and RPM of the prop relative to the aircraft is the main thing to consider. These aircraft had large, heavy props, that exerted significant gyroscopic character. Some modern aerobatic aircraft like the Extra 300/Edge 540 Sukhoi 31 etc. use a composite 3 or 4 blade props that are very light and have minimal gyroscopic character. . . you didn't see these in WWII. Wood props are better than metal with respect to gyroscopic action, but they are not suitable for the higher performance aircraft or those with constant speed props.

    As far as how it is implemented in the sim, well, generally you need rudder less in the sim than you should, the sim tends to auto-coordinate aileron and rudder (though this patch improved things a bit in this regard), but the gyroscopic effects are a bit too harsh and abrupt, primarily when releasing stick pressures. That said, the real world practice of adding left rudder when pulling back (in CW engine rotations) and right rudder when pushing forward is correct, and is a great addition to the sim, even though it needs to be refined.
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  8. #8
    Originally posted by tomtheyak:
    <BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by NorrisMcWhirter:
    The effect is there and I think it's fair to say that the gyroscopic effect may be the reason why planes recover from stalls all by themselves.

    Ta,
    Norris
    To be honest Norris, I just am not getting the insta stall recovery you refer to... nor spins - if you are refering to recovery in the incipient spin however then letting go of everything will have the tendancy of letting the a/c sort itself out - after all, your control inputs would tend to be the reason for the stall to occur, especially in an accelerated stall, and relinquishing input would allow the a/c to drop back into an AoA regime whereby it is no longer at the stall stage (tho close) and let it try to trim itself out as all a/c have a tendency to.

    Once in the full spin (which incidentily is actually a very stable form of oscillation and therefore difficult to recover from) I find getting ANY of these fighters out before at least two or three FULL turns very difficult - and that seems to bear much resemblance to real life tales of spins in these a/c.

    Have a little look at these sites:

    http://oea.larc.nasa.gov/PAIS/Concep...echnology.html

    http://www.fcitraining.com/vid_clip9_incipient_spin.htm

    they give excellent descriptions of how what and why spins and stalls differ and recovery methods. And bear in mind the recovery techniques will differ for different airframes. </div></BLOCKQUOTE>

    Hi,

    I did refer to it as a stall..I meant a spin, yes - sorry.

    Stalls, as you rightly point out, autorecover like before. Spins are different, though. In fact, one of the most difficult planes to get out of a spin was with the I16 and this typically meant bailing out if you were at low alt. I've had one recover from a spin when I had no tail fin anymore (shot off at the fuselage). It just recovered....I was so surprised by this that I put it into a spin again..and let it recover again.

    My point is that, IMO, things are easier than before and a lot of aircraft require no action to recover from even quite bad spins.

    Ta,
    Norris
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  9. #9
    Thanks again for the answers guys!

    As far as spins and gyro effect are concerned,

    a plane with a clockwise turning prop as you see it from the cockpit if it went in a left corkscrew, would it have the tendency to automaticaly raise the nose and keep itself in the spin? Would the opposing happen if it went in a right corkscrew? Would it then have the tendency to drop the nose and autorecover?

    Cheers!!!
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  10. #10
    Originally posted by Jatro13th:
    Thanks again for the answers guys!

    As far as spins and gyro effect are concerned,

    a plane with a clockwise turning prop as you see it from the cockpit if it went in a left corkscrew, would it have the tendency to automaticaly raise the nose and keep itself in the spin? Would the opposing happen if it went in a right corkscrew? Would it then have the tendency to drop the nose and autorecover?

    Cheers!!!
    Absolutely!

    To perform a deliberate upright flat spin in a CW engine aircraft you must enter a conventional spin to the left, (then add out spin aileron for best effect and at the same time) increase power, and as you add power the nose will rise towards the horizon, the rotation rate will slow some, and the aircraft will often stabilize with the nose about 30 degrees below the horizon ina flat spin. At this point the pilot can attempt recovery and if power is left in the spin very well may not recover at all, it may either continue on in the spin or transition into an inverted spin (adding forward stick alone will accellerate the spin rotation, adding forward stick and opposite rudder is the way to enter an inverted flat spin so if this is done that’s what will happen, which is often fatal as it’s very confusing to most pilots), it is critical in the real world to get power at idle in a flat spin. To perform an inverted flat spin the pilot must now use right rudder to initiate the spin.

    For this reason an upright spin to the right, or inverted spin to the left, should recover very quickly and easily.
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