Spit IIa

[Osprey]

Originally Posted by VO101_Tom

So what changed?
Edit: These speeds are without WEP. The "Notleistung" is 20% plus power that these should be added (of course, the efficiency of the propeller and the air resistance due to the growth rate of less than 20%, but it is certain that more than 10km/h)

I think you'll have to wait until the next patch where we know that FM's are being worked on before we can evaluate things.

[Fenrir]

Your efforts Crump are becoming tiresome, and frankly your arguments about the spitfires 'Dangerous Instability' are verging on laughable. Every post that you put up serves only to advertise your bigotry and deepen your alienation of the rest of the forum.

I'll leave on this;

1) A pitch unstable aircraft is not pleasent to fly; it tightens in turns and does not settle automatically from a disturbed path. IT is VERY hard work. EVERY pilot who has flown a Spitfire, particularly those who have flown in combat say time and again the similar thing; words like DELIGHTFUL, EASY and WONDERFUL are repeatedly used to describe the handling and time and again they use the analogy that you didn't get into a Spitfire YOU PUT IT ON. Not to labour the point, but how on earth is there any correlation between these two factors? Cos apparently according to you they co-exist in the same airframe.

In case you missed it the first time, I'll write it again: Spitfires stability was MARGINAL. That does NOT make it UNSTABLE. You, with your self proclaimed expertise on aerodynamics should know this.

2) This bob weight stuff you seem hung up on is a poor argument; I have already related as to how it only affected Mk.V variants - thats Mark Five by the way; introduced many months after the Mk I & II in game - and was a result of increasing amounts of ancilliary equipment that was loaded into these a/c being poorly loaded at squadron level. But yet AGAIN you seem to have missed or ignored someones counter argument when it doesn't fit your model. So, yet AGAIN I'll direct you to Jeffrey Quill's excellent book on the subject. But somehow I get the feeling you won't read it; might not fall into line with some of your 'well founded' opinions.

Crump, your only working to serve your increasing reputation as a stuck up opinionated blowhard. One of these days you're gonna post something ace, a real piece of pukka gen as the old saying goes, and know one round here's gonna give a monkeys cos your credibility is vanishing with every cherry picked argument you present. But please, if you wish to continue shooting yourself in the foot......

[Crumpp]

spitfires 'Dangerous Instability' are verging on laughable.

Pilots died from it....

A pitch unstable aircraft is not pleasent to fly; it tightens in turns and does not settle automatically from a disturbed path.

Like this??

From the Spitfire Mk II Pilot Operating Notes:



The same warning is in the Spitfire Mk I which contains even more details.

If you want I will scan the pages from my college text from my stability and control classes. They deal a lot with the Spitfire and the DC-3 as both are famous icons that lack the most basic of stability, longitudinal. Unfortunately, Stability and Control engineering was new science at the time and nobody collected data on just how many accidents could have been prevented had these airplanes had acceptable longitudinal stability.

There is no agenda or bias, bud. You can learn something or not.

Notice, this is not MY opinion.....









Here is part of that text book. Read the last myth on a stable aircraft being less maneuverable than an unstable one.

http://books.google.com/books?id=D-c...0myths&f=false

[Fenrir]

What kind of verification do you have for these sources Crummp? As far as I know you've written that stuff on an old typewriter and scanned it. Besides, when it says 'failed to meet requirements' - whose?! What requirements? For all I know the Spitfire fails to meet requirements for a heavy lift wide body! Context man, for pitys sake.

Besides, if what you infer is correct we'd have seen spitfires and DC-3s - or more accurately, there constituent parts - scattered all over the landscape because every single one was an inherently dangerous saftey hazard. Take a look how many survive into the modern day and are flown regularly and aerobatted reguularly without incident. Look at the war record of these a/c. Since when on either type is it apparent that they were falling out of the sky in pieces with a methodical regularity?

Do I have to point out that the pictoral example of a structural failure that you provide IS A BLOODY Mk. FIVE again.

Gimme strength!

Besides which where on that photo/drawing does it show that this breakup was caused by excessive g due to instability? Oh that's right, it doesnt. It could have been faulty construction, metal fatigue, flutter, any number of causes. You just assume that it's down to some inherent flaw with Spitfires stability because you've got your axe to grind.

As for your quote on the Mk. II that buffeting can cause large variation in stick travel and g - wow, revelation. Any one who's read into the spitfire knows how sensitive the elevators were. At what what point does it say ANYWHERE in that text that the a/c is longitudinally unstable or prone to taking itself to pieces in that text? It does not. You're extrapolating, badly while your at it, tying it in with other flawed and irrelevant data.

The simple fact is your opinion extrapolated from text book teachings do not correlate with the historical record from a massive amount of disparate sources. And your one textbook evidence - whose validity I suspect - is not only being qouted without context - again WHAT & WHOSE requirements - but upon re-reading them it even agrees with me - NOTE the passage that you underlined 'the small static longitudinal stability',

It says small. It does not say none. It says the stick was very sensitive to movement in pitch.

It does not say Spitfires were falling apart all over the sky.

AT NO POINT DOES IT SAY THAT A SPITFIRE IS DANGEROUSLY AND INHERENTLY UNSTABLE.

[Fenrir]

Sorry just had to laugh; read the first line of your text, then the last line of the text under the 3rd image.:

Pilots died from it....

Er.... But then death and serious injury are the same thing aren't they? Like marginal stability and none, apparently.

[VO101_Tom]

Originally Posted by Fenrir

Sorry just had to laugh; read the first line of your text, then the last line of the text under the 3rd image.:

Why? If he died, he never flew again...

I find it interesting, but I do not think it Crumpp prove that the Spitfire was a bad aircraft, which is obviously not true. But there was not a perfect plane, perhaps, as some would like to believe. The Spitfire is a legend (in a good sense of the word), and not wonder if something like these test results, opinions have never enjoyed great popularity.

[TomcatViP]

Fenrir comments are way too much aggressive to be relevant.

Nothing that Crumpp has says is a non-sense unless over interpreted by the reader. It fit actually many well known aero principles.

By the way Fenir, the marginal mkV was just the most mass produced Spit variant ever.

[Crumpp]

Spitfire was a bad aircraft,

Who said the Spitfire was a bad aircraft? DC-3 is not a bad aircraft either.

the marginal mkV

The RAE investigated a series of fatal accidents and concluded that pilots were overloading the airframe on recovery.

The longitudinal instability was not corrected until the Mk V with the installation of bob weights to increase the stick force per G. Bob weights certainly help the pilot to maintain better control of his accelerations but they did not fix the actual problem of insufficient vertical and horizontal stabilizer area. That too was fixed in later marques as stability and control matured greatly as a science during the war. At the time the Spitfire was designed, the United Kingdom did not have a standard and there was no such thing as a stability and control engineer. It just was not that big a deal at the low speeds of open cockpit biplanes common before the war. As speeds and power increased though, it became very important.

Nothing that Crumpp has says is a non-sense unless over interpreted by the reader. It fit actually many well known aero principles.

Yeah folks are very emotionally tied to the Spitfire. I can even remember students in class defending it. That is why it makes such a good example for fledgling stability and control engineers.

Think about what the NACA says on the stick travel. You only have 3/4 of an inch of travel to run the wing from a CL of .3 to CLmax. The minimum standard was 4 inches.

It is no wonder the Operating Notes suggest the pilot brace himself on the cockpit walls to control the aircraft. Imagine trying to land on a gusty day getting tossed around the cockpit with only 3/4 of an inch movement between controlled flight and a stall spin accident.

[JtD]

Originally Posted by Fenrir

...What requirements?...

The Spitfire was at about 5 lb/g, requirements were around 8 lb/g. So it was too light on the elevator.

It would be unstable if it was <=0 lb/g. It wasn't.

P-39 was less stable, with down to 2 lb/g at the most rearward CG allowed.

[TomcatViP]

Originally Posted by JtD

It would be unstable if it was <=0 lb/g. It wasn't.

I don't get you ?! Negative mass in a Spit ? Is that in concordance with the black mass theory ?

Do you mean inverted ctrl ?

Unstable means either that you have a too variable force to pull/push per deg of pitch (ideally it would hve been linear) or that you encounter a zone were the stick forces are reversed (but not negative). For ex the WWI Camel had a degree of reverse ctrl were you needed to push on he stick to raise the nose further up.