Stability and Control characteristics of the Early Mark Spitfires

[taildraggernut]

intersting article from NASA....

http://history.nasa.gov/monograph12/ch4.htm

[Glider]

Nice one, I like this bit on the SPitfire

FIGURE 4.5. Supermarine Spitfire airplane. A high-performance fighter noted for its role in the Battle of Britain and throughout WW II, the Spitfire had desirably light elevator control forces in maneuvers and near neutral longitudinal stability. Its greatest deficiency from the combat standpoint was heavy aileron forces and sluggish roll response at high speeds.

Crumpp this is a must read for you

[taildraggernut]

Originally Posted by Glider

Nice one, I like this bit on the SPitfire

FIGURE 4.5. Supermarine Spitfire airplane. A high-performance fighter noted for its role in the Battle of Britain and throughout WW II, the Spitfire had desirably light elevator control forces in maneuvers and near neutral longitudinal stability. Its greatest deficiency from the combat standpoint was heavy aileron forces and sluggish roll response at high speeds.

I thought it was worth making the 'desirably' bold too

Interesting to note the 'near neutral longitudinal stability' persumably this is because it was slightly longitudinaly unstable, but not unstable enough as to be regarded a problem.

[Crumpp]

http://www.spitfireperformance.com/k9788-stability.jpg

[Crumpp]

slightly longitudinaly unstable

The records are posted above....

You guys understand this is quantifiable and not opinion?

I guess I will run some calcs for you all so you can get a better idea of the effect.

[taildraggernut]

And?........

The graphs show a slight instability, if you cant cope with that level of divergence in 3 minutes then my guess is you'd either be paralysed or in a coma.

[robtek]

There are speed changes of about 70mph in less than 15 second documented, if that doesn't take the pilots attention away from other things i don't know what would.
Of course a pilot can manage to control this instability, but he has to work just to keep his ride in a controlled flight, add other factors as gusts, attacking 109's or else and the workload might become too large.

[taildraggernut]

a cessna 152 will go from 70 to 0 in less than 15 seconds......the point is you have to wait a few minutes before those fluctuations get to that level, within the 1st minute nothing on those graphs looks wildly out of control.

[TomcatViP]

Crummp I think you shld stop answering to them. It goes nowhere. Either this thread shld be locked now if you have finished exposing your point or you might switch to the next step in your argumentation.

Don't take me wrong, I found your point really interesting as many other does.

[Sandstone]

Originally Posted by robtek

There are speed changes of about 70mph in less than 15 second documented, if that doesn't take the pilots attention away from other things i don't know what would.
Of course a pilot can manage to control this instability, but he has to work just to keep his ride in a controlled flight, add other factors as gusts, attacking 109's or else and the workload might become too large.

The question is whether the increase in workload caused by the Spitfire's longitudinal stability actually amounted to very much at all. Crumpp has been unable to show that it did and the lack of pilot accounts that even mention longitudinal stability suggests that there was no great problem, even for low-hours pilots. I suspect this is partly because the frequency of the pitch oscillations resulting from the instability was quite low. It's hard to see where this discussion can go given these facts.

Further, I really can't see how pitch sensitivity or instability could in any case be modelled in a flight sim where players use short, spring-centred joysticks with response curves. The situation is made worse in CoD because there is no turbulence or weather in the game (or at least I can't recall any from when I had it installed, but that was many months ago).