Aircraft nose up

[xinmayu]

hi, all guys,

My aircraft always 5 to 10 degrees nose up when cruising at high attitude, such as FL350. The higher I go, the larger AOA is. But i am not climbing, I am cruising at normal speed.

Anybody knows why? How to solve it?

THanks for help.

Andy

[IanK]

Hello Andy,
how many versions of FS to you run?

Andy
on Today at 05:25, xinmayu wrote:hi, all guys,  
 
My aircraft always 5 to 10 degrees nose up when cruising at high attitude, such as FL350. The higher I go, the larger AOA is. But i am not climbing, I am cruising at normal speed.  
 
Anybody knows why? How to solve it?  
 


That is a bit excessive. In Fs2004 you need to move the lift slope in T404 .air to the left by 5 to 10 degrees to get a level fuselage. In FS2002 and previous change the Wing Incidence parameter but this makes it incompatible with upgrading to newer sims.

Thanks for help.  
 
Andy  



Ian2

[xinmayu]

I am having both FS2002 and FS2004 on my PC. I fly FS2002 more. Why?

[IanK]

If you want models to be compatible with both FS8 and FS9 to give them another name then they need to take into account how many times MS will change its mind in how to make it as Real as It Gets. So only Change T404 as Wing incidence and twist are ignored in FS9 and zero both of these so they will fly correctly in both sims.

I think I answered a similar thread elsewhere...looking..

Ian

[Mr.Mugel]

If you fly really high, the Air get

[IanK]

FS5.*=>MSFS5.*
FS?=>MSFS95
FS?=>MSFS98
FS7=>MSFS2000
FS8=>MSFS2002
FS9=>MSFS2004
FS10=>Vapourware

Maybe I was getting confused.

Only if the TAS is constant so that CAS falls and lift coef (CL) increases. So from T404 the lift slope you will see that AoA will have to increase.

Typically in the linear lift region CL = CL_@_zero_AoA + lift_slope * AoA

Typically a/c fly at constant CAS therefore flying at an increasing TAS with increasing altitude.

The U-2 at FL800 needed about M0.8
Concorde at FL550 needed M2.2
The SR-71 at FL700 needed about M3.2

Ian

[OTTOL]

That sure is a long way to say "the angle of attack increases with altitude".    What you're seeing is normal.   The Lear 35, for instance has a normal AOA of 3degrees above zero at lower altitudes and as much as 6 or more in the flight levels. And you don't have to be "above FL600" to experience this.

As a matter of reference. Later 20 series and all 30 series Lears have tip tanks mounted at a 3degree down angle to produce less drag at high altitudes!