Unbalanced load?

[nigglascage]

hey all :)

 

my plane always wants roll to the right and im not able to trim it out perfectly.. is that normal? im pretty new to dcs a10 and not really sure if its only due to unbalanced load.

i'm not having this issue on any training missions btw.

 

when i press ctr+enter everything seems to be centered too.

 

my setup:

stick: thrustmaster hotas warthog

pedals: saitek pro flight combat

 

many thanks in advance

Edited June 24, 2013 by nigglascage
typo

[IonicRipper]

If you have an asymmetrical load (more weight on the right or left wing) it is very normal. Try without any weapons loaded, it should fly straight.

[nigglascage]

If you have an asymmetrical load (more weight on the right or left wing) it is very normal. Try without any weapons loaded, it should fly straight.

 

thanks for the swift reply!

i guess the load is always heavier on the right wing when using "create fast mission" and therefor the plane rolls slightly to the right without trimming - can anyone confirm that?

[shagrat]

thanks for the swift reply!

i guess the load is always heavier on the right wing when using "create fast mission" and therefor the plane rolls slightly to the right without trimming - can anyone confirm that?

basically any loadout that has a TGP on one side or the ECM pod is unbalanced... pretty normal.

If you have crosswind it affects the plane, also.

EDIT: try trimming left wing down a bit before take off, or just push a little aileron left to counter...:smilewink:

[311Gryphon]

thanks for the swift reply!

i guess the load is always heavier on the right wing when using "create fast mission" and therefor the plane rolls slightly to the right without trimming - can anyone confirm that?

 

These guys have you covered and I certainly don't know the specifics of how and why but my plane almost always rolls a little. And most of the time I can't trim it perfectly but I can get it close enough that I don't have to watch where I'm flying even if I chose not to engage auto pilot.

 

If you haven't yet (I suspect you have but just in case) I would remap the trim hat on your HOTAS stick to...trim. I'm not sure why it's mapped to views as default. Maybe to help those that don't have some kind of head tracking????

[Flamin_Squirrel]

If you have crosswind it affects the plane, also.

 

Only for takeoff and landing. Otherwise, once in the air, the plane couldn't care less what the wind is doing with respect to the ground.

[NhiTrac]

I see you fly with a TMWH. See the trim hat on top of the stick? Remap that to trim instead of pan view and get used to mashing it every so often for a near level flight.

 

Ps with my usual loadout, once I'm airborne I usually trim left about 6 clicks and up about the same until my airspeed increases, then I'll trim down to fly level. As soon as you release a weapon (unbalance your plane) however, be ready to trim left/right again.

 

And check out the other thread about flying level. Same question you have...

Edited June 24, 2013 by NhiTrac

[nigglascage]

i greatly appreciate all the help! this forum is awesome :)

[OzStriker]

Only for takeoff and landing. Otherwise, once in the air, the plane couldn't care less what the wind is doing with respect to the ground.

 

Correct for a steady breeze but not for a change of wind speed or direction.

[Flamin_Squirrel]

Correct for a steady breeze but not for a change of wind speed or direction.

 

A change in wind speed or direction will have an effect on a plane yes, but not in the context of uneven weight, which is what this thread is all about.

[OzStriker]

Yes it will have an effect on the aircraft in any context, irrespective of asymmetric anything.

 

You have completely ignored the fact that windshear, which is a significant change in direction or groundspeed of wind has destroyed ultralights and 747s and everything in between.

 

So aircraft and pilots do very much care about what the wind is doing with respect to the ground.

[Flamin_Squirrel]

Yes it will have an effect on the aircraft in any context, irrespective of asymmetric anything.

 

Precisely, windshear has an effect irrespective of asymetry. So why, given that asymetry is what this thread is about, did you bring it up? By your own admission it's irrelevant. :doh:

[mhe]

Actually it is not only windshear, it is wind itself. An aircraft in a crosswind has the tendency to yaw its nose into the wind. This comes from the cross-section profile of the aircraft with the tail being very large and being pushed harder from the side than the rest of the aircraft. If you have a yaw-moment into the direction the wind is coming from, the outer wing will have a slightly higher airspeed than the inner wing, resulting in the outer wing producing slightly more lift - therefore the aircraft slightly banks to the inside of the turn.

 

You have the same effect of aileron and rudder being "linked" aerodynamically - step on the rudder only and the aircraft will bank as well.

 

Try it out - fly an empty aircraft straight and level in a crosswind, trim it out perfectly. Then reverse your heading 180 degrees, wings level and let everything go. If your assumption of wind direction being of no significance would be right, the plane would fly perfectly straight. But in fact it isn't.

 

Try it at about 20 knots crosswind enroute for example, you will notice the difference.

 

But yes, an asymmetrically loaded plane will either counter this effect or make it much more pronounced, depending if the asymmetry makes the plane roll into the direction the wind is coming from or not.

Edited June 25, 2013 by mhe

[Irregular programming]

I have never managed to load a plane to the point that I couldn't trim it.

 

Certainly not on the quick missions.

[OzStriker]

Actually it is not only windshear, it is wind itself. An aircraft in a crosswind has the tendency to yaw its nose into the wind. This comes from the cross-section profile of the aircraft with the tail being very large and being pushed harder from the side than the rest of the aircraft. If you have a yaw-moment into the direction the wind is coming from, the outer wing will have a slightly higher airspeed than the inner wing, resulting in the outer wing producing slightly more lift - therefore the aircraft slightly banks to the inside of the turn.

 

You have the same effect of aileron and rudder being "linked" aerodynamically - step on the rudder only and the aircraft will bank as well.

 

Try it out - fly an empty aircraft straight and level in a crosswind, trim it out perfectly. Then reverse your heading 180 degrees, wings level and let everything go. If your assumption of wind direction being of no significance would be right, the plane would fly perfectly straight. But in fact it isn't.

 

Try it at about 20 knots crosswind enroute for example, you will notice the difference.

 

But yes, an asymmetrically loaded plane will either counter this effect or make it much more pronounced, depending if the asymmetry makes the plane roll into the direction the wind is coming from or not.

 

Urrrrrgh this is so so wrong. An aeroplane doesn't weathercock in the air. Please be quiet.

[mhe]

Urrrrrgh this is so so wrong. An aeroplane doesn't weathercock in the air. Please be quiet.

 

Care to explain your "argument"? A perfectly trimmed aircraft will not weathercock, that's right. But that is only true for perfectly static wind conditions where you counter cross wind drift with the perfect amount of wind correction angle. And these theoretical conditions rarely occur in reality, bar from perhaps a simulated environment.

 

But go ahead and do the test I suggested. ;)

 

An aircraft not experiencing any attitude change from crosswind would mean it would have to follow any fluctuation in windspeed perfectly, meaning it would have to have no inertia whatsoever.

Edited June 25, 2013 by mhe

[OzStriker]

these theoretical conditions rarely occur in reality, bar from perhaps a simulated environment.

 

I cannot make any sense of your post but this bit is funny :)

[mhe]

So you cannot make sense of what I'm saying but yet you claim that everything I say is wrong? :huh:

 

I smell trolling... ;)

[OzStriker]

The language you are using suggests you don't have much of a grasp on what you're talking about, from either a theoretical or practical perspective. It is making it hard to follow what you're on about, which shouldn't be the case with my knowledge and level of experience.

 

I stand by my comment, your first post was wrong. I'm sorry but please don't try to explain things in here when you don't understand them properly.

[mhe]

Ok, so your argument is "I am so great and knowledgeable and you are wrong". If I am so wrong, please correct me. Communities are there to share the knowledge you know. ;)

 

I love constructive criticism as it enables one to learn. If you want me to shut up, prove me wrong with substance instead of just claiming the high ground by default. You have yet to come up with anything of substance to do so.

 

The drag of an aircraft's side profile is not the same over the area, thus a crosswind force will be more absorbed on one point than the other. If the tail is pushed harder sideways due to it having more drag seen from the side, it will result in the aircraft slightly yawing, the banking will be the result of previously stated effects.

 

And while we are at it - applying aileron trim to a unbalanced aircraft will result in unbalanced lift to counter the unbalanced masses. This is great, but asymmetric lift also creates asymmetric drag, which will in turn have to be countered by rudder/rudder trim.

Edited June 25, 2013 by mhe

[311Gryphon]

I have to say in the name of learning that what mhe is saying does make a certain amount of sense to me. I'm not very experienced although as I've said some in other posts that I took ground school before. There's a lot that we learned in that that I've forgotten and a lot that you can't learn from books and only in application.

 

So if mhe is incorrect I for one would like to know how he's incorrect and why so that I don't learn the wrong things or even learn the right things but for the wrong reasons.

 

Thanks.

[HugePanic]

What you mean is maybe described as a gust! A short term change in wind direction or speed.

 

Gusts are usually not respected in aerodynamical discussions, except it is a special topic.

Usually you assume a quasi-static wind.

You also usually assume is un accelerated horizontal flight, unless the discussion is about manoeuvering.

 

So MHE, I also agree your statement seems to be wrong.

 

If you put a ship without motor or sails in a river. What's the direction of the hull in relation to the stream??

[mhe]

I may be wrong, but as stated before, I'd love to know the reasons for it being so.

 

I have my problem with the ship analogy, as water is uncompressible and therefore hardly comparable to air. And yes, the ship will be drifting. Chances are, it will also rotate a bit while drifting. And it is this rotation/yaw that causes all the other things I stated in an aircraft. All these theoretical sidedrifts without rotation stem from a simple vector model where one assumes that all the forces act on one point (which is very convenient mathematically), but once you look into forces acting on different points with different grades of "efficiency" (because wind and water can simply put more force on an object the more friction/drag there is), things get a lot more complicated.

 

As said, I have no problem with being proven wrong, I love standing corrected. But I refuse to accept that something is wrong just because one guy says so without giving any reason whatsoever.

 

Let's just say I have an academic interest in the topic. ;)

[HugePanic]

Assumption: indicated airspeed of the AC is 100m/s. Heading is north. Wind is constant at 10m/s from west to east. --> direction 90degree

 

 

Compared to the ground, in 1s the plane will fly "forward" 100m. At the same time, the plane will drift 10m to the east.

 

So now think of one air molecule as it sits next to the aircraft. It will also move 10m to the east in 1s.

The same will happen to all air moluceles around the area.

 

So why do you think any air-molecule is moving in east-west direction RELATIVE to the aircraft????

 

There is no relative movement, means no side force on any part of the plane. If you have the canopy open or not, it does not matter, since there is no relative side-wind.

 

The aircraft does not "see" the crosswind.

 

Does this help you??

[Flamin_Squirrel]

As said, I have no problem with being proven wrong, I love standing corrected. But I refuse to accept that something is wrong just because one guy says so without giving any reason whatsoever.

 

Let's just say I have an academic interest in the topic. ;)

 

An excellent attitude to have! HugePanic's explanation is quite good I think.

 

As he says, it doesn't matter how strong a steady wind across the ground is, a plane will still be flying straight through the air that surrounds it. The complecation is that during takeoff with a crosswind, for example, this no longer true; the plane is traveling straight along the ground, which may not be in the same direction of the surrounding air. This is when you get weather cocking into the wind, but once airborne, this goes away.