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Guest idratherbeflying

Finally got Flight1's Cessna 172 - question for rw pilo...

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Hi folks,Searching for a single prop I would fly for real when leaning to fly, I finally opted for Flight1's Skyhawk. Great plane.However, I have a question related to the gyro effect. As I take off and fly, I constantly need to make corrections to compensate for the gyro drift. If let go the commands, the plane just turns to the left. After searching in this forum, someone suggested to sit a fat guy in the left seat. I'll try that, but I was wondering if in real world flying, the gyro drift is that present. Remember that I'm really looking for the closest real world experience (to help me with my learning process). If the gyro effect is this present, I'll keep it that way (as I don't think I'll fly that ofter with a fat passenger - not that I have any problem with fat guys, it's just that I don't know that many :)).My realism settings are set to maximum, and I checked the "spinnable" flight model in Flight1's config application for the Cessna.Thanks in advance for your input folks.Louie.

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I'm assuming by gyro drift you mean that the directional gyro in the panel drifts off the heading shown by the magnetic compass? That's correct. In RW flying you check and adjust the DG to match the magnetic compass approximately every 15min or so during level unaccellerated flight. Depending on the health of the gyro and vaccum system you might find little change, or if it's getting really old and weak and ready for overhaul it might be off by quite a lot. Since everything I fly has glass or HSIs I don't recall the acceptable drift/15min off the top of my head.As for the aircraft not maintaining heading when you release the yoke, the 172 has a fixed trim tab attached to the rudder. These are generally adjusted (bent) so that the aircraft flys coordinated, straight and level at cruise speeds. Sometimes they may need a little tweaking, but generally the aircraft isn't going to drift much for short periods of hands-off flying. If you let go and it just goes into a large bank or turn, then the tab (or in this case perhaps the p-factor slider?) needs to be adjusted accordingly.

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The tendency of the plane to pull to the left is call P-factor (or P-torque) and it caused by propeller. The vortex of air that the propeller generates around the fuselage eventually hits the elevator and the plane will turn left.Most plane designs compensate for some of the effects and you can trim it with the rudder anyway, so that you can fly are comfortable straight and level flight.Pat

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Just a little bit of trivia regarding the directional gyro.An ordinary Directional Gyro (DG) "suffers" from something called precession (I think that

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To add to Pat's description:P-factor is highest at large angles of attack (slow speed and climbing is the usual configuration where this is encountered), and is a result of assymmetric thrust effect from the prop due to the angle of attack. Use copious amounts of right rudder in a C172 to counteract. There are also other effects such as that of prop wash that Pat referred to, that are constantly present even in level flight. However as airspeed increases, so does rudder authority, so at higher speeds it's much easier to counteract- in fact many 172's have a small trim tab (immovable other than by bending the aluminium tab) that countacts almost all of the level flight stuff.Bruce.

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Yeah agree, you certainly feel the lighter weight of being solo but it doesn't contribute one way or the other to a turning tendancy in a one seventy two anyway. :-)

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In real world flying I have found it varies from plane to plane, my own C172 used to always gradually turn to the left, went on for a long time until the engineer adjusted the trim tab more aggresively. Now it will pretty much stay straight and level. I have flown other C172's which behave differently, some turn slightly to the left other straight.. it all depends on the airplane itself and how the trim is adjusted.

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Does it matter whether the right seat is empty or has a fat guy sitting in it? If it matters, then how much? R-

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:)The width of a C172 fuselage is so small that the "fat guy" has no moment. Whenever I fly with only myself in the left seat, or someone along in the right seat, I notice tha weight as it affects take-off peformance (at 5,000 + feet in the Denver area), but never the tendancy to turn.Bruce.

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>Hi folks,>>Searching for a single prop I would fly for real when leaning>to fly, I finally opted for Flight1's Skyhawk. Great plane.I don't agree about the flight one 172. I looked for a 172 when learning to fly in 172s, but found this one to be nothing like the 172 I was using. In fact, for a similar feel to real flying, I found the Carenado Cherokee to be really good.>However, I have a question related to the gyro effect. As I>take off and fly, I constantly need to make corrections to>compensate for the gyro drift. If let go the commands, the>plane just turns to the left. After searching in this forum,>someone suggested to sit a fat guy in the left seat. Wouldn't that make the effect worse?>I'll try that, but I was wondering if in real world flying,>the gyro drift is that present. Remember that I'm really>looking for the closest real world experience (to help me with>my learning process). If the gyro effect is this present, I'll>keep it that way (as I don't think I'll fly that ofter with a>fat passenger - not that I have any problem with fat guys,>it's just that I don't know that many :)).Real aircradt are designed to fly straight and level at cruise speeds. Some have tabs on the rudders that are bent into position to stop the left turn. Some aircraft have the engine angled very slightly out of line with the fuselage to stop the turning tendency at cruise.Ray Keattch

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> After searching in this forum,>>someone suggested to sit a fat guy in the left seat. >>Wouldn't that make the effect worse?My suggestion was actually to put the "fat" guy in the "right" seat.MSFS tends to over amplify this out of balance situation a bit.However, flying a small GA aircraft with shorter wings than the 172, say 23' versus the 172's span of 36', you'll most likely notice the imbalance more. >Real aircradt are designed to fly straight and level at cruise>speeds. Some have tabs on the rudders that are bent into>position to stop the left turn. Some aircraft have the engine>angled very slightly out of line with the fuselage to stop the>turning tendency at cruise.>Some more info on engine offsets, since a lot of aircraft have them. The back of the engine is offset compared to the centerline of the firewall, while the forward prop line is at center. The vertical stabs may also be offset.L.Adamson

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>My suggestion was actually to put the "fat" guy in the "right">seat.:) Correct, my mistake. I meant right seat (that's funny: I'm afraid that flying with a fat guy sitting on my lap would not help the situation at all.)>MSFS tends to over amplify this out of balance situation a>bit.That's what I thought. Thanks for your input everyone. Very informative.Louie.

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