Stability and Control characteristics of the Early Mark Spitfires

[Crumpp]

From "Aerobatics Principles and Practice" by David Robson, ex Fighter Pilot,Miltary test pilot (ETPS graduate.)

Right....

Edge of the Buffet is not IN the buffet.




If you have no other guide, the buzz is useful for finding CLmax. Don't fly in the nibble but back off to just before though IF you want maximum turn performance.

Lift varies with angle of attack and airspeed. The highest useful angle of attack is just before the critical angle, about 15 degrees. At this high angle of attack, maximum CL, considerable drag is produced, and if the aeroplane stalls, or the buffet is reached, the drag will increase dramatically. Ideally, sufficient backpressure should be applied to activate the stall warning (if it is operating) on its first note. Alternatively, the very edge of the buffet will need to be used as a guide to maximum CL.


http://www.caa.govt.nz/FIG/advanced-...ate-turns.html

You can fly in the nibble if you want, IvanK. However somebody that is turning in the same airplane at the point of smooth air just before the nibble will out turn you. That is how the physics works.

Its not a case of not "wanting" to be in the situation... Operational pilots often find themselves in situations they dont want to be in. The question put was quite specific, a Spitfire MKI no AOA gauges no accelerometers just you the pilot and your basic airframe.

Right.....Again, I would not want to be in that situation with a neutral or unstable aircraft with a light stick force per G and extremely small amount of available stick control.

That why we see charge sheets with "structural failure" and "wings came off in aerobatic flight".

But you did say that Cambridge and others used the Spitfire wing when you clearly don't know
Quote:

Making up what????

Start another thread on this off topic sideshow. 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.

[Crumpp]

either substantiate your claim or withdraw it

Why don't your read Morgan and Shacklady. They have a list of the serial numbers and known fates of many of the Spitfires.

They even have pictures of the remains of some of the aircraft that shed wings during high speed maneuvering.

Are you going to make me scan them or can you just pick up the book and read it?

[NZtyphoon]

Originally Posted by Crumpp

Why don't your read Morgan and Shacklady. They have a list of the serial numbers and known fates of many of the Spitfires.

They even have pictures of the remains of some of the aircraft that shed wings during high speed maneuvering.

Are you going to make me scan them or can you just pick up the book and read it?

In fact it's much easier going through http://www.spitfires.ukf.net/ which is better researched and better laid out, and more accessible, then M & S.

Originally Posted by 6S.Manu

Infact it's the entire picture... they says those were the accidents reported to them... it's only a speculation that they were the only accidents during all the war as you said since:

1) Was the AAIB the only one actually called to investigate on accidents?
2) How many accidents were not reported?
3) We don't know the AAIB method of investigation: did they need the wreck?... or they could investigate by interviews with the witnesses of the accident?
4) As you says, I repeat, I can be that some accidents not reported as result of a past investigation. A plane is losing its wings during recovery from a dive? The first accident of this kind required an investigation, probably also the second one... but how many until it's clear that the plane can be pull so much and it become ?

1) The body responsible for investigating air accidents before and during WW2 was the AIB (Accidents Investigation Branch) which was responsible for investigating all air accidents. http://www.aaib.gov.uk/about_us/history.cfm
2) Why bother speculating on a question which can never be answered? It's like asking how long is a piece of string.
3) Presumably whatever was available - if a wreck was at the bottom of the sea AIB would not have gone chasing after it.
4)Again, unquantifiable speculation

[bongodriver]

1) Was the AAIB the only one actually called to investigate on accidents?
2) How many accidents were not reported?
3) We don't know the AAIB method of investigation: did they need the wreckage?... or they could investigate by interviews with the witnesses of the accident?
4) As you says, I repeat, I can be that some accidents not reported as result of a past investigation. A plane is losing its wings during recovery from a dive? The first accident of this kind required an investigation, probably also the second one... but how many until it's clear that the plane can be pull so much and it become ?

1) in all probability yes....it's their job, why call in people who aren't qualified?
2) probably a very small amount, in all likelyhood just the events which lead to MIA and unknown fates.
3) as long as the methods produced the answer does it matter?
4) let's not forget that most Spitfire pilots were flying with a squadron and the squadron pilots are all credible eye witnesses to what happens, through all of the recounted stories and biographies etc nobody ever mentioned the Spitfire as being 'particularily' weak or seeing squad mates breaking up with any regularity.

[6S.Manu]

Thks for the answers.

Originally Posted by NZtyphoon

1) The body responsible for investigating air accidents before and during WW2 was the AIB (Accidents Investigation Branch) which was responsible for investigating all air accidents. http://www.aaib.gov.uk/about_us/history.cfm
2) Why bother speculating on a question which can never be answered? It's like asking how long is a piece of string.
3) Presumably whatever was available - if a wreck was at the bottom of the sea AIB would not have gone chasing after it.
4)Again, unquantifiable speculation

Originally Posted by bongodriver

1) in all probability yes....it's their job, why call in people who aren't qualified?
2) probably a very small amount, in all likelyhood just the events which lead to MIA and unknown fates.
3) as long as the methods produced the answer does it matter?
4) let's not forget that most Spitfire pilots were flying with a squadron and the squadron pilots are all credible eye witnesses to what happens, through all of the recounted stories and biographies etc nobody ever mentioned the Spitfire as being 'particularily' weak or seeing squad mates breaking up with any regularity.

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.

A Department could delegate some accidents to a company and other crashes to another: my doubt is the existence of another qualified company during that time... it's a natural to make use of external help (the AAIB was indipendent) during difficult times. So is it sure that the RAF had not a internal investigation departement and AAIB was the only responsable? Could it be that it was responsable for the accidents in a determined territory (England)?

2) & 3) I ask because of the possibility of not investigated accidents regarding structural failure: if so the Mr.Newton's numbers posted by Glider are far less interesting: as I said, since those were only accidents with a defined wreckage, how many more planes went down for structural failure over the sea (the channel, Malta ect)?
I think an investigation would always require witnesses... my question was if there would be an investigation at all in case of no wreckage.

4) Bongo, I know... infact I expect that the loss of the wings was a rare accident: I think more of a not critically damaged airframe for which, I think to have read somewhere, the plane had to be partially rebuild... could a plane with partial airframe damage have the same performance? Does its manouvrability and stability remain the same? Because IMO in combat area easily a damaged plane would be taken down by the enemy...

I know it's speculation, but not useless IMO. To have the complete picture we need to be sure of these things, otherwise there is no absolute truth.

[Crumpp]

See Henshaw

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.

Now let's compare that to the Beechcraft Bonanza which also had some developmental issues with the V-tail that resulted in structural failure. It is the airplane that forged the "Doctor Killer" reputation.

>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

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.

The events of WWII overshadowed the longitudinal instability issue in the early Mark Spitfires.

[Crumpp]

4) As you says, I repeat, I can be that some accidents not reported as result of a past investigation. A plane is losing its wings during recovery from a dive? The first accident of this kind required an investigation, probably also the second one... but how many until it's clear that the plane can be pull so much and it become ?

#4 Again, unquantifiable speculation

It is not speculation. It is a fact, the early mark Spitfire had neutral to unstable longitudinal stability at normal and aft CG. It is a fact, the controls were too light and too effective.

This combination is why you see the warnings in the Operating Notes.

It was real and it could kill you if ignored.

[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.

[Glider]

Once again you are putting your own spin onto a paper that it presented to you.

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

Where does he say only Mk 1 and II's? He doesn't so lets apply your logic to all the spits produced in the war
23,000/25 = 920

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

So for every 920 Spitfires one was lost to structural failure

Now let's compare that to the Beechcraft Bonanza which also had some developmental issues with the V-tail that resulted in structural failure. It is the airplane that forged the "Doctor Killer" reputation.

>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.

So for every 920 Spitfires produced in the war ( I could increase this number to all spits built) One experienced a structural failure.
In other words you are about 8 times safer in a Spit in wartime than in a peacetime Bonanza

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.

I think the early Mark Spitfire would have had a much better reputation in peacetime than the Bonanza due to its much safer record iro structural security

[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...