During my flight light roll problem with left wing...

Hello guys,

 

I have one question about the roll of the F-86, after the take off and during the beginning of my flight the pitch and roll are fine but after many long minutes to flying I have one roll problem, my F-86 roll slowly to left wing and I can't fix this problem with my trim.

I can shake and move in any angle my stick but always this left roll, I've tested with my P-51D, A-10C and other SU-25A-T and my F-15 but I don't have this problem, my HOTAS TM Warthog work fine...

 

I don't think that the left internal fuel tank create this problem, please guys can you tell me if you have noted this roll problem ?

 

Thanks in advance, Skull.

Maybe you are approaching Mach 0.92/0.93 or 550KIAS at low altitude. That's roughly the speed where the aircraft tends to roll left/right and becomes really hard to control.

It's called 'wingheaviness'.

 

From the product page:

 

High speed

 

Between high indicated airspeed and Mach number (within the flight restrictions), a series of unique characteristics manifest themselves in aircraft behaviour.

 

Starting at Mach 0.9, unintentional roll (wingheaviness) (to the left or to the right) manifests itself and it strengthens as the Mach number increases up to its limit values. Appearance of this wingheaviness is associated with the geometric asymmetry of half-wings and also with their unequal flexural-and-torsional load-deflection curves. The wingheaviness is accompanied by a significant decrease of the aileron effectiveness related to wave effects and wing deformation during their deflection.

 

The airflow compressibility influence on longitudinal flying qualities at high speeds remains insignificant up to the Mach 0.95. With further increase of the Mach, the aircraft demonstrates excessive tendency to pitching-up, the compensation of which requires additional pushing force on the control stick.

 

Due to the above-mentioned peculiarities of the aircraft behaviour, the indicated air speed is restricted to 600 knots.

 

Reason: Developing wing heaviness at considerable decrease of the aileron effectiveness (at high values of the Mach number) and additional wing bending and wing torsion under the action of the airflow at aileron deflection.

 

Acceleration higher than the value of the Mach 0.93 is only possible when decending.

 

Also what kind of maneuvering were you doing previous? It is possible that you hit very high G numbers and have damaged your plane (wing warping) I read in another thread somewhere that this is modelled with the F-86 and would cause the exact issue you are having... (And I have done it myself and can attest to the fact that if you get silly with the maneuvering you can in fact cause damage that will affect the handling adversely..)

Yes I well undestand your explanation but with Mach 0.5 and 300 KIAS I have this roll left, is it normal ?

 

Also what kind of maneuvering were you doing previous? It is possible that you hit very high G numbers and have damaged your plane (wing warping)

Yes each time that I meet this problem I hit very high G, anybody can tell me if with F-86A it's possible ?

 

Thanks again, Skull.

Edited July 31, 2014 by Skulleader

If you have previously damaged your plane with too high of G forces I suspect you could see that kind of roll at ANY speed...

 

(Or were you referring to the post by Turbohog?)

you have trim on axis? from external view the ailerons stay in place?

If you have previously damaged your plane with too high of G forces I suspect you could see that kind of roll at ANY speed...

Yes you have probably reason because there's few minutes I've tested one flight without "High G", just 4G positive and 1G negative.

For this flight just one takeoff, fly for 30 minutes and after the landing and I do not meet any problem with my roll.

But tonight I will tested other flights with the Sabre.

Or were you referring to the post by Turbohog?

Where's this post ?

 

you have trim on axis? from external view the ailerons stay in place?

Just trim the pitch axis not the roll axis and concerning the external view I've no tested but tonight I test this external view...

 

Guys, I would like to thank you and if you have any feedbacks it's perfect for me.

 

Bye, Skull.

Edited July 31, 2014 by Skulleader