Stability and Control characteristics of the Early Mark Spitfires

[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?

[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.

[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?

[Glider]

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.

evidence please. which airframe and supporting evidence as to what test the plane was to meet

Also still waiting for your piles of wings waiting to be fixed in BOB

[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?