# Stability



## Zipper730 (Nov 2, 2017)

I was reading some of the books that Captain Eric Brown wrote, and I noticed he was referring to the Spitfire as neutrally stable and as I understand it: Neutrally stable means that if g-load or AoA is increased, it will stay that way if the stick is neutralized provided no change in speed occurs...

Is there more to it than that?


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## pbehn (Nov 3, 2017)

Zipper730 said:


> I was reading some of the books that Captain Eric Brown wrote, and I noticed he was referring to the Spitfire as neutrally stable and as I understand it: Neutrally stable means that if g-load or AoA is increased, it will stay that way if the stick is neutralized provided no change in speed occurs...
> 
> Is there more to it than that?


This is discussed and explained on pages 4 and 5 of the attached. DO NOT ASK ME TO CLARIFY ANYTHING IN IT.
http://www.wwiiaircraftperformance.org/mustang/Lednicer_Fighter_Aerodynamics.pdf


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## Zipper730 (Jan 14, 2018)

No change in trim needed when making changing speed...


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## pbehn (Jan 14, 2018)

Zipper730 said:


> No change in trim needed when making changing speed...


That's what it says and was a feature of the early Spitfires at least, generally referred to as a part of the harmony and balance of controls. 

I have never flown a plane but I did race motorcycles, the Suzuki X7 had the steering and braking while the Yamaha RD250 had the high speed cornering, stability and torque. At the same time (briefly) on the road I had a Honda CB 900 which was considered a "Superbike" , it was a dog, high CoG, long wheel base and narrow tyres, meant I never felt the wheels were under the engine (or me) and CV carbs meant you were putting in a written request for more power some time in the future, and you always got more or less than you wanted. I occasionally raced against CB 900s and beat them, though a good rider would beat me every time, to be honest even the guys I beat had my respect, there is no way I would take a camel like that on a track. At the limit balance harmony and ease of control make a difference, the Spitfire was such a joy to fly even Americans wrote poems about it, with words so beautiful they are quoted by Presidents at a time of great loss.

Oh! I have slipped the surly bonds of earth,
And danced the skies on laughter-silvered wings;
Sunward I've climbed, and joined the tumbling mirth
Of sun-split clouds, --and done a hundred things
You have not dreamed of --Wheeled and soared and swung
High in the sunlit silence. Hov'ring there
I've chased the shouting wind along, and flung
My eager craft through footless halls of air...
Up, up the long, delirious, burning blue
I've topped the wind-swept heights with easy grace
Where never lark or even eagle flew --
And, while with silent lifting mind I've trod
The high untrespassed sanctity of space,
Put out my hand, and touched the face of God.


RIP John Gillespie Magee Jr.


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