Stability and Control characteristics of the Early Mark Spitfires

[NZtyphoon]

Originally Posted by Crumpp

Good stuff...

He says 25 were lost due to structural failure he uncovered in his research. That is quite a few.

That is only the ones that were lost due to total failure as well as the ones we know about. It does not tell us the number of aircraft which flew home with bent wings or the ones that broke up over enemy territory.

To put that 25 unfortunate Spitfires in perspective:

~2488 Spitfire Mk I and II's were produced

2488/25 = 99.52

So for every 100 Spitfires, one was lost to structural failure.

Garbage, he's talking about all Spitfires built



~20,351/25 Spitfires built = 1 in 821

Originally Posted by Crumpp

>17000 Beechcraft Debonair/Bonanza's have been built.

Taking structural failures from 2007 on back we find that 148 airframes have been lost. We have much better records of a peacetime GA aircraft.

http://www.thomaspturner.net/infligh...ups%20NTSB.htm

17,000 / 148 = 114.8

So, For every 115 Beechcraft Debonair/Bonanza's built, ONE has experienced structural failure.

http://www.tsgc.utexas.edu/archive/g...ics/vtail.html

Originally Posted by Crumpp

I think the early Mark Spitfire would have had the same reputation in peacetime as the Bonanza due to its high rate of structural failure.

Nope, the Beechcraft, a high speed interceptor fighter built to withstand combat conditions in wartime, was 7 - 8 times more likely to fall apart.

Originally Posted by Crumpp

He says 25 were lost due to structural failure he uncovered in his research. That is quite a few.

That is only the ones that were lost due to total failure as well as the ones we know about. It does not tell us the number of aircraft which flew home with bent wings or the ones that broke up over enemy territory.

One can speculate on this as much as one likes - unless Crumpp or anyone else can provide documentary evidence to back such statements that's all it is. Besides which Spitfires returning home, even with buckled wings (assuming the stacks of buckled wings seen in MU hangers can be believed), were not destroyed through structural failure and could be repaired and put back into service.

To match Beechcraft Bonanza stats for every Spitfire known to have been destroyed through structural failure another 4.5, or over 100 at least would have to fail over enemy territory - a wonderful propaganda opportunity had it happened. No doubt Crumpp can present lots of documented evidence that this happened.

Originally Posted by IvanK

So now we have Beechcraft Bonanzas and Debonairs in this Spitfire thread !!!!!! .... talk about thread drift.

Keeping with the drift though, in your Bonanza V tail structural failure number crunching example you quote 17,000 Bonanza/Debonairs being made but isnt the Debonair a single fin aeroplane ? Did it have the same structural issues as the V tail Bonanzas ? If it did fair enough but if it didn't should it be included ?

Dont really care either way just saying.

The V-tail has a very high rate of in-flight failures. Compared with the Model 33, which is the same aircraft with a conventional straight-tail, the V-tail has a fatal in-flight failure rate 24 times as high as the Straight tail Bonanza. In spite of this glaring statistic, Beech claimed that there was no problem with the V-tail, and for many years the public seemed to agree with Beech. However, the deaths from in-flight failures continued to mount. The V-tail Bonanza is a classic tale of a dangerous item, which because of its popularity continued to kill.

Can't remember anything like this being written about the Spitfire, even by its harshest critics, including NACA and the Pilot's Notes...

[Crumpp]

Because IMO in combat area easily a damaged plane would be taken down by the enemy...

That is correct. A bent airframe is not good. The plane is hard to control and weakenend.

I ask because of the possibility of not investigated accidents regarding structural failure

There were plenty of uninvestigated accidents. In wartime, they would be chaulked up to the enemy. Common sense tells us that wings coming off in a dogfight would be chaulked up to enemy fire or pilot suddenly breaking out of a turn to wings level was hit.

There would be no way to resurect the dead or examine the wreckage to discover the airframe was broken during a flick maneuver or bent in a hard turn above Va.

Facts are we will never be able to quantify that statistic. None of this changes the defined and measured characteristics of the aircraft nor does it invalidate the Operating Note warnings.

Where does he say only Mk 1 and II's?

The issue was solved in the Spitfire Mk V!!

You understand that the bob-weights and subsequent empennage changes to the design were to fix the instability??

It is only a factor in the early Mark Spitfires.

Aerodynamically, the instability is a very easy fix. The only reason it was not solved much earlier is the fact the Air Ministry had no defined standards for stability and control. Without measureable standards, the pilot stories of "easy to fly" simply overshadowed the few engineers who knew better.

[NZtyphoon]

Originally Posted by Crumpp

The issue was solved in the Spitfire Mk V!!

You understand that the bob-weights and subsequent empennage changes to the design were to fix the instability??

It is only a factor in the early Mark Spitfires.

Please provide documented evidence that Henshaw was only referring to Spitfire Is and IIs, otherwise this is just clutching at straws.

AA876 Vb 2223 EA M45 FF 25-10-41 during test flight 6-2-42 George Pickering reached a speed of 520mph in a dive. The aircraft disintigrated He was severely injured and never flew again. SOC before delivery not to be replaced. Airframe to RAE 9-4-42 for accident invest

MA480 IX CBAF M63 46MU 1-6-43 82MU 14-6-43 La Pampa 2-7-43 Casablanca 14-7-43 Middle East 1-9-43 Dived into ground Egypt FACB 10-10-43

[Al Schlageter]

So can we take it that Crumpp, given, the chance, would not pilot an early Mk of Spitfire as it was a death trap?

Notice they are all over the sky and even upside down.
http://www.youtube.com/watch?feature...&v=TXxzlOH92as

http://www.youtube.com/watch?v=c6c3v...eature=related

[Glider]

Originally Posted by Crumpp

That is correct. A bent airframe is not good. The plane is hard to control and weakenend..

True but it gets you home a broken one doesn't

.

The issue was solved in the Spitfire Mk V!!

You understand that the bob-weights and subsequent empennage changes to the design were to fix the instability??

It is only a factor in the early Mark Spitfires..

True but you need to prove that he is only talking about Mk I and II. Its worth remembering that the fix wasn't in place for the start of Mk V production so you need to factor that in.

And you still need to prove that there were any bent wings in the BOB waiting repair let alone the statement you made. Without evidence you have no back up and its only another unsupported theory.

[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.

On a side note, X4181 on 17-840 was designated in 616 Squadron for "100 Octane Testing" and was shot down by a Bf-109 on 26-8-40.

Should have read this list earlier!!

[Glider]

We do seem to be in the normal situation where one side produces evidence to the best of their ability and often in duplicate. And the nay sayers produce nothing to support theirs and depend on ever more silly questions.

On the Bent wings waiting repair being a 1944 issue
1) An original document from the NA which is clear as to the cause of the problem in late 1944 and how to resolve it
2) the 2TAF series of books from C Shores a highly recognised author on aviation which also says the same

On the Bent wings waiting repair being a BOB issue
1) Someone says that they remember reading something somewhere
2) Crumpps statement with nothing to support it
In other words nothing

On the number of Breakups due to structural faiulure being small
1) A published work written by someone involved in Air Investigations for 50 years
2) The numbers matching those printed in the M S book
3) Henshaws paper the number are different but even lower

On the numbers of breakups being higher
1) I looked in the website but I asked because it's not written that's the only responsable of investigation but it's part of the entire Department.In otherwords the department has more responsibilities and this section is responsible for Air Investigations.
2) Statements that others may have come down at sea or in enemy held areas.
Of course this almost certainly happened. However its a question that we will never know the results to. Its something that happens to every airforce all we can do is do the best we can with what we know. In the same way we do not know how many of these had been damaged in combat.

[6S.Manu]

Originally Posted by Glider

We do seem to be in the normal situation where one side produces evidence to the best of their ability and often in duplicate. And the nay sayers produce nothing to support theirs and depend on ever more silly questions.

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

Originally Posted by Glider

On the number of Breakups due to structural faiulure being small
1) A published work written by someone involved in Air Investigations for 50 years
2) The numbers matching those printed in the M S book
3) Henshaws paper the number are different but even lower

And you call this evidence!?!?

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

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.

3 books: one has different numbers... Which ones are the corrected numbers?

Look I've "produced" a question about that data...

Originally Posted by Glider

On the numbers of breakups being higher
1) I looked in the website but I asked because it's not written that's the only responsable of investigation but it's part of the entire Department.In otherwords the department has more responsibilities and this section is responsible for Air Investigations.

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.

Originally Posted by Glider

2) Statements that others may have come down at sea or in enemy held areas.
Of course this almost certainly happened. However its a question that we will never know the results to. Its something that happens to every airforce all we can do is do the best we can with what we know. In the same way we do not know how many of these had been damaged in combat.

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.

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?

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.

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

[Glider]

Originally Posted by Crumpp

. Cambridge awards degrees, they published the book, and it is used as a reference in many engineering curriculuums.

If you don't like those facts, tell Cambridge not me.

Cambridge don't issue degrees, they do publish books which are used in institutions but they do not teach.

However and most importantly we are still waiting for your evidence to support your statement about piles of bent wings in the BOB.

Without evidence your statement is useless, should be withdrawn and without it your argument goes with it.

You will agree I am sure that it the professional approach