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View Full Version : Cross wind and tricycle landing gear



XyZspineZyX
07-28-2003, 08:24 PM
When taxiing in a P-39 at 30 KPH with a ~10-20 KPH cross wind blowing from the right, the P-39 tries to veer off to the right and requires full left rudder. Although this would be a correct behaviour for a tail-dragger, a crosswind should not affect a tricycle landing gear (P-39) this way (unless it is a *very* strong wind).

S!
SKULLS_LZ

XyZspineZyX
07-28-2003, 08:24 PM
When taxiing in a P-39 at 30 KPH with a ~10-20 KPH cross wind blowing from the right, the P-39 tries to veer off to the right and requires full left rudder. Although this would be a correct behaviour for a tail-dragger, a crosswind should not affect a tricycle landing gear (P-39) this way (unless it is a *very* strong wind).

S!
SKULLS_LZ

XyZspineZyX
07-28-2003, 09:26 PM
I am afraid your a little incorrect. Trike gear light (12,000lb and under) aircraft are affected by a crosswind component. The specs on them even have specification for a crosswind tolerance.

Even in taxi-ing they are affected. I am aircraft mechanic and have handled small airplanes in real life.
Many is the time in moving them around I have had to apply counter input to offset the crosswind. In maintenance flights I have felt the plane drift to one side a bit on take off.

You apply a force perpindictular to the tail and it is going to try to turn due to the moment arm from the tail to the center of gravity of the aircraft.

XyZspineZyX
07-28-2003, 10:00 PM
Heavies tend to have more weight on their nose gear to give them the friction to counter it though... until the NWG leaves the ground, that is. By that time, a heavy will typically have more speed though, rendering the xwind component relatively smaller. They'll feel it though, 12,000 lbs is not a magical limit. /i/smilies/16x16_smiley-wink.gif

Tricycle gear usually handle it better. However, the P39 has a free castoring NWG. That won't help you much!

Cheers,
Fred

No sig as of now, as people apparently can't handle reality without creating too much trouble for the poor mods.

XyZspineZyX
07-29-2003, 05:54 PM
Thanks for the replies, but
effte wrote:
- P39 has a free castoring NWG.

Not in FB. Sitting still, apply rudder, and nose wheel turns like its fixed solidly on end of shaft. Either way there's something wrong. I don't dispute that a cross wind would have some effect on a taxiing P-39, but can't see how 10 - 20 Kph wind would require full rudder to counter (with a non-free-castoring nwg).

XyZspineZyX
07-30-2003, 07:06 AM
So the P-39 does NOT [in real life] have NWS? Does the ME-262 have NWS [the real one]?

I know the FB P-39 has NWS, and the 262 doesn't.

XyZspineZyX
07-30-2003, 08:35 AM
all aircraft are effected by crosswind

the strength of the tendency to weathervane into the wind depends mainly on the distance from the tail to the axis of the main wheels

obviouslyaerobatic planes with large tail and rudder surfaces will also be more susceptible

however as far as i know the main reason tail-draggers have a reputation for being more suceptible is the main wheels are often mounted further forward giving more leverage

XyZspineZyX
07-30-2003, 10:26 AM
WTE_Galway wrote:

- however as far as i know the main reason
- tail-draggers have a reputation for being more
- suceptible is the main wheels are often mounted
- further forward giving more leverage

It's a bit worse than that. For obvious reasons the gear is placed in front of the centre of gravity, making the whole thing directionally unstable. This means that any tendency to swing will be amplified by its own motion, always making it want to ground-loop and roll tail first down the runway. Every such tendency must be countered with rudder (or at really low speeds, with differential braking) before it becomes problematic (i.e. very quickly.)

A plane with a nose gear obviously has CoG in front of the main gear, which makes it directionally stable. It will veer due to prop effect and wind, but the veering will not accelerate due to its own motion.

If the nose wheel is castoring, it cannot counter cross-forces, so it will require more countering (same as if the nose wheel is above ground,) but far less so than for a tail dragger plane.
_
/Bjorn.

XyZspineZyX
08-02-2003, 05:14 AM
hey swingman

finally someone that knows what they are talking about with the taildraggers

i really wish that was modelled right in FB, ive been going on about it since the demo came and and pretty much get ignored

i say we put together a group of taildragger whiners, lol, and get that fixed, heh

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XyZspineZyX
08-02-2003, 05:44 AM
As for the taildraggers the first thing you should do is LOCK TAILWHEEL. The only time I ever leave a tailwheel unlocked is when i need to make a sharp turn [on or off the runway] while taxiing.

XyZspineZyX
08-02-2003, 05:31 PM
Unfortunately, the P-39 maybe modelled to have a turnable nose wheel, the Flight Model is not set up for nose wheel steering. The "Q" turns on the ground no better (and in some cases worse) than any tail dragger in the game. For the Me262 to not have nose wheel steering, or at least a turnable nose wheel, is ridiculous. You can't build a tricycle gear aircraft and not have the nose wheel turn. Just imagine how many tires they would have to go through (especially during the rubber shortage during the war) trying to turn the jet (or prop; sorry, I'm a crew chief... if it flies, it's a "jet") with the nose wheel stuck straight ahead.

SSgt Tim Schuster
8MXS Inspection Section
Kunsan AB, Korea

-Defend the Dock!
-Accept Follow-on Shifts!
-Take the Fight Upstairs!

XyZspineZyX
08-02-2003, 09:23 PM
VOL_Jon wrote:
- As for the taildraggers the first thing you should
- do is LOCK TAILWHEEL. The only time I ever leave a
- tailwheel unlocked is when i need to make a sharp
- turn [on or off the runway] while taxiing.
-
-

yes, but there is hardly a need for it in FB right now, in real life there is no way a taildragger will take off without any rudder input, its gonna ground loop(spin around and try to go tail first), but in FB you can take off or land with no rudder, it might go a little off to one side, but you can still take off or land



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