Yaw trim vs Roll Trim on Final - Page 2 - ED Forums
 


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Old 07-02-2019, 03:54 PM   #11
bbrz
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Don't fully understand what you are trying to say. Again, I'm talking about the airplane in the air, not on the ground.
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Old 07-02-2019, 04:49 PM   #12
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Don't fully understand what you are trying to say. Again, I'm talking about the airplane in the air, not on the ground.
im talkning about trasition from air to ground

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Old 07-02-2019, 05:12 PM   #13
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you have to agree that crosswind forces aitional trimming in plane
No, since you don't use rudder and/or aileron trim during or for the flare!
Additional lift is only created when you are e.g. applying rudder to align the airplane longitudinal axis with the runway centerline after a crabbed approach, but this is also not wind related.
When you touch down, the upwind wing can be lifted due to the crosswind, but then you are not in the air anymore

Last edited by bbrz; 07-02-2019 at 05:15 PM.
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Old 07-02-2019, 07:39 PM   #14
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You should adjust your trim when entering the pattern and then typicality leave it alone. On final its power, stick and rudder. In crosswinds that are significant for the ac you are flying, (lighter ac being more susceptible to lighter crosswinds), you apply aileron to dip the upwind wing in the direction of the crosswind and you use rudder to keep your longitudinal axis centered on the runway center line. Or at least that's how it works in real flying. Crosswind landings in DCS are kind of underwhelming. hope that helps...

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Old 07-02-2019, 08:03 PM   #15
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Originally Posted by bbrz View Post
No, since you don't use rudder and/or aileron trim during or for the flare!
Additional lift is only created when you are e.g. applying rudder to align the airplane longitudinal axis with the runway centerline after a crabbed approach, but this is also not wind related.
When you touch down, the upwind wing can be lifted due to the crosswind, but then you are not in the air anymore
i meant for crusing not for landing

no in tail dragger after touch down you are still flying the plane touch down is just begining especialy in strong cross wind situation

Last edited by grafspee; 07-02-2019 at 08:08 PM.
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Old 07-02-2019, 09:28 PM   #16
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Having just received my taildragger certification...
Put your control stick over into the direction of the crosswind (Eg if wind is coming from your direct left then put the stick over to the left) after you land to avoid any unpleasant issues with crosswind. And keep the stick back after landing to keep the tail down.

Of course a Mustang is a lot heavier than say an A1c husky so ymmv.

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Old 07-02-2019, 09:44 PM   #17
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Thanks for all your help everyone.
So what I am understanding (apart from the physics are complicated!) is that I shouldn't be focusing on trim too much but be using the stick to control the aircraft? Or rather, I should expect an appropriately trimmed aircraft to still need stick input, even when lined up, despite there being no wind/munitions effect.
Fuel in the wings is an interesting one I hadn't considered, though not sure it's having an affect here as I am just spawning in 2km from the runway to practice landing.
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Old 07-03-2019, 02:18 AM   #18
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Originally Posted by Bazmack View Post
1. I shouldn't be focusing on trim too much but be using the stick to control the aircraft?
2. I should expect an appropriately trimmed aircraft to still need stick input, even when lined up, despite there being no wind/munitions effect.
3. Fuel in the wings is an interesting one I hadn't considered, though not sure it's having an affect here as I am just spawning in 2km from the runway to practice landing.
1 Exactly You don't control an aircraft with trim. With trim you are only 'trimming away' the force required to constantly apply elevator/rudder/aileron.

2. Once you are trimmed for your approach speed and you don't need apply any power changes, you 'theoretically' don't need to trim anymore.
But as soon as the speed starts to decrease/increase, or you need to climb/descend, you would need to re-trim. Since these changes are only short term changes, you don't need to trim.
Furthermore we are talking about an high performance prop fighter which is by far less stable than e.g. a C172 so you can expect that it will never fly perfectly straight and level for a prolonged length of time.

3. Fuel doesn't have any effect in such a short time span. Not even during a complete pattern.
Generally you should basically use aileron (trim) to correct a lateral imbalance and rudder (trim) for power changes.

One last item; on final a few miles out I usually neutralize rudder trim since I'm going to land power off, and I want that my plane flies in straight line in this case.

That said, 2km from the runway is a very short distance and very little time to get the airplane trimmed out.
At this point my rudder trim is usually already at neutral and an imbalance isn't a factor, so you only have to fly the airplane the last few seconds...

edit: just re-read your assumptions in your initial post are all correct. Just don't assume that a P-51 will continue on its approach track indefinitely on it's own.
Even the slightest change in power and/or pitch would require re-trimming, but see above concerning short term changes.

Last edited by bbrz; 07-03-2019 at 02:32 AM.
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Old 07-04-2019, 11:17 AM   #19
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Quote:
Originally Posted by bbrz View Post
NO! For the airplane there is no such thing as a crosswind. The ground track changes and you must adjust the heading. That's all.
There's absolutely zero change in lift etc....
In RL take off and landings with cross wind, a small wing down trim into the crosswind is required (most of the time)

I don't know why it is (I'm not a pilot) but a friend of mine is and when I asked him for a crosswind procedure, he told me they always have to apply a bit of wing down to the wind in the A320 when taking off on crosswind.

Now on the OP problem with the Mustang, as long as you have prop traction, you will always have a bit of slip, and the mustang is famous for being very nervous on the changes of throttle.

I usually use direct rudder on take off and landings to counter the small adjustments on throttle. Trim is not fast enough.
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Old 07-04-2019, 11:43 AM   #20
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Originally Posted by Eviscerador View Post
1. In RL take off and landings with cross wind, a small wing down trim into the crosswind is required (most of the time)

2. I don't know why it is (I'm not a pilot) but a friend of mine is and when I asked him for a crosswind procedure, he told me they always have to apply a bit of wing down to the wind in the A320 when taking off on crosswind.
Please re-read what I wrote several times. I'm talking about the airplane in the air, not on ground!

1. On ground you need aileron into the wind to avoid the wing being lifted, but definitely no aileron trim, since the effect is gone as soon as wheels are leaving the ground.

2. See point 1. That's only applicable on ground during the takeoff run.
Btw in planes without FBW you also have to apply aileron into the wind immediately after touchdown during the landing run for the same reason.

Last edited by bbrz; 07-04-2019 at 11:46 AM.
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