Stability and Control characteristics of the Early Mark Spitfires

[bongodriver]

Originally Posted by 6S.Manu

Of course!! But it's seems that some people really don't care about having a realistic sim.

Yes, and I've been argueing with them for 70 odd pages now.

[Crumpp]

They restricted the CG.



The Spitfire is placarded against spinning.

......we all know they were allowed to spin right?

His Mustang is prohibited from spinning too.

I know you are going to come straight back with the 'look, it says no intentional spinning' but that is a blanket ban on permit to fly aircraft for similar reasons to the RAF's operational reasons during the war, an unnecessary and risky manouver and the aircraft are very expensive.

Of course, nothing to do with the original aircraft being placarded.

[bongodriver]

They restricted the CG.

By how much? I think you will find the CoG is probably different because there are no guns or ammo, anyway the point is proved that you were wrong and 'no' modifications such as you claimed were carried out.

The Spitfire is placarded against spinning.

Just like many other aircraft

His Mustang is prohibited from spinning too.

Yes, that's what I'm saying, why have you made this comment?

Of course, nothing to do with the original aircraft being placarded.

But everything to do with the reasons why I mentioned.

[MiG-3U]

Originally Posted by bongodriver

By how much? I think you will find the CoG is probably different because there are no guns or ammo, anyway the point is proved that you were wrong and 'no' modifications such as you claimed were carried out.

Thanks for posting the CAA links!

The CoG limits are exactly the same as given in the revised manual for the standard elevator without inertia device and with DeHavilland propeller. At normal service load the CoG was around 7.7" aft datum point so there was no need for the bob weight. Without the seat armour and weapons the CoG is of course even more forward.

However, the NACA tested Spitfire had the Rotol propeller which was more sensitive for the CoG due to lighter blades, hence the aft limit was 7.5" aft datum point without bob weight and NACA had the CoG at 7.8". In other words such loading was not allowed without bob weigh according to revised CoG limits. Also the Spitfire II manual quoted many times here is for the Rotol propeller, hence the warnings before the CoG limits were revised. The manual for the DeHavilland propelled aircraft and the later revisions, after the CoG limits were revised, do not contain such warnings.

Now, we have here about 70 pages of some members (apparently all from blue side for one reason or another) demanding that the stability and elevator control of the early Spitfires should be modeled according to the worst case scenario; Rotol propeller and the CoG behind the limits for such combination

BTW wasn't there some one claiming that the all currently flying Spitfires have the bob weighs?

[Glider]

Originally Posted by 6S.Manu

Curiosity and research for detail are silly questions?... tell me you're not an historian...

I do consider myself to be an amature historian, which is why I always have some substance behind my theory and statement. It may not be everything everyone want but there is something.

Lets take the example of the bending of the wings. Crumps says this happened a lot and there were piles of wings to be repaired. My belief is that this happened in late 1944 when Spitfires were being used for tassks way beyond what they were designed for. I produced two different sources both of which are very clear and invite Crumpp to supply his evidence that this happened in the BOB. Result silence.
I could have pointed out that the fix was very simple, clip the wings of the SPitfire as thats what they did in 1944. If bending had been a problem in the BOB then the solution would have been quick and effective, clip the wings of the Mk I and II spits. I could have pointed out that this wasn't done and that would indicate that there wasn't a problem with the bending of the wings. But I didn't, why, because I wouldn't say such a thing without proof.

And you call this evidence!?!?

Its more than you have put forward. You have a theory but nothing behind it

What about the M S book having the same source of "Spitfire at war" => AAIB?

Possible but very unlikely. The reports are procduced during the war, the book many years later.

Now if the AAIB data is not usefull to understand the real rate of structural damage, since it ignores the accident over the sea and in enemy territory, what is the meaning to post it?
The real numbers are different, period, since we don't know how many poor guys died for overstressed airframe and they were filed as KIA because of the enemy.

There is no way they can know for certainty as to what happened in some cases over german held areas. However you accuse them of ignoring accidents which is insulting and you do it without evidence which compounds the insult.
You are also factually wrong. The vast majority of Typhoon losses due to the loss of the tail happened over Germany areas but this wasn't ignored. The pilots were aware of what was going on, it was reported and the issue was addressed. To pretend that Spits breaking up would be ignored is clearly wrong and without evidence again insulting.
You may well question my approach to historical facts but I would never, ever, say such a thing without something to support what I said.
I await your supporting evidence with some interest, note evidence not theory. It shouldn't be difficult as you believe it happended so often finding an unexplained loss that was put forward and then ignored should be straight forward.

Really? I ask it because I don't know... I would like a doc by the Air Ministry stating that every accident need to be investigated officialy by the AAIB.

Or if Mr.Newton said "We had to investigate every accident during the war" it would be enough. But it does not say it... so sorry if I've some silly doubt.

If you want that then I suggest you go and look for it. Of course you can have a theory but a theory it remains unless and until you can support it. The AAAIB can only look at things that are referred to them, it always was and should always be that any unexplained accident should be reported to them. You forget that its in the interest of the pilots and crew to report these incidents as their lives are on the line

Then that number about the rate of Spitfires lost for airframe damage is almost useless since it's a small sample mostly no related to combat. That was my first statement.

Its not a small sample it all the incidents that were reported to them. If you believe that there were others that were ignored then support that statement. Again without evidence its a theory without support

In enemy territory, in combat, numbers can easily be different. Are numbers about accidents because of clouds really important when they did fight at 5km??? Does the pilot need to land in the fog in enemy territory?

This I have already covered

So lets stick to the data about stick forces, oversensivity, AoA e structural limits and lets try to analyse them together. Without the necessity to bring on numbers and reports who do not help.

Or is that pilot reports, test pilot reports, test establishments reports and official accidents reports that are to be ignored because they are inconvenient?

Mainly because THEY DID NOT FLY AS WE DO IN THE SIM.

I don't hear Crumpp, yourself or anyone else demanding that the Spitfire be easy to land, easy to take off, be faultless in a turn and always turning inside the Me109 as did the German pilots and test establishments or are you in favour of such realistic factors

[Crumpp]

The Spitfires listed by bongodriver have Merlin 35 engines. The Merlin 35 engine is ~1550lbs dry weight. I did not catch that.

The Merlin III is 1375lbs dry weight.

The Merlin 35 is a post war engine and adds considerable weight to the front of the airplane shifting the CG forward.

The guns are removed along with all of the magazine, heating, and ducting also shifts the CG forward.

You can bet the new limits are not unstable or netural at any point.

It would be interesting to see the new weight and balance of the modern Spitfires.

[Crumpp]

If bending had been a problem in the BOB

Bending was a problem in the BoB. The RAF wanted it investigated and fixed. In August 1940, they provided a test aircraft to meet that goal.

[bongodriver]

Originally Posted by Crumpp

The Spitfires listed by bongodriver have Merlin 35 engines. The Merlin 35 engine is ~1550lbs dry weight. I did not catch that.

The Merlin III is 1375lbs dry weight.

The Merlin 35 is a post war engine and adds considerable weight to the front of the airplane shifting the CG forward.

The guns are removed along with all of the magazine, heating, and ducting also shifts the CG forward.

You can bet the new limits are not unstable or netural at any point.

It would be interesting to see the new weight and balance of the modern Spitfires.

But haven't you been maintaining that the CoG is not the bigger issue with the Spitfires stability problems?

[NZtyphoon]

Originally Posted by Crumpp

Just going thru the list in Morgan and Shacklady, I have counted 13 structural failures so far and I am only halfway thru the Mark I list.

It was serious enough that X4228 went to Farnborough on 24-8-40 to be used in testing to discover the cause of wing structure failures.

Serial Numbers please, and please scan and post the relevant pages. How many of them were elderly airframes in OTUs?

There was no Spitfire I serialed X4228

[41Sqn_Banks]

Originally Posted by Crumpp

Bending was a problem in the BoB. The RAF wanted it investigated and fixed. In August 1940, they provided a test aircraft to meet that goal.

Source?