Spitfire Compared to Hurricane in the BoB

[MiTasol]

Hi
The book 'Airframe Construction and Repair' by John T Henshaw, Pitman 1943, has information on repairing tubes:

Also 'quick' release fasteners for access panels were common, these are from my own technical training notes from the early 1970s, but on the whole in use by WW2:

The Amal, for instance, was used on the Hawker Typhoon and other Hawker aircraft, the Fairey was used on the Spitfire, but also they were used on interwar aircraft.

Mike

Hi Mike
Good very basic reference but first option always is what is specified in the manufacturers manuals - in this case AP 1564B Vol II Part 3, written by the factory to an AM specification. In the case of the Hurricane the tubing used was not a weldable alloy so only scab patches could be used. If you looked at MiFlyer's earlier post it is unlikely that a scab patch could be used on any of the cluster joints so that only leaves replacement.

If major load carrying components of the fuselage assembly are damaged and the assembly needs to go in a jig, it might be more economical to scrap the aircraft but without a detailed hidden damage inspection, your assessment is a very wild guess to say the least. To say a P-40 "would have" faired better is even a wilder guess!

And "scrapped" Spitfires were sent to the nearest factory to be upgraded to the latest model and given a new serial number.
If the wings were perfect they would just get a new serial and new paint job. If not the same as the fuselage - upgrade and reserial.
One of the reasons why no-one knows how many Spitfires were produced.

 

[Greyman]

Agree, so I somewhat question the validity of that test unless those deflections were able to be identified.

The test is perfectly valid -- my inference is the issue.

Aircraft losses due to structure damage seem to make up a low percentage of causes. Generally, I think by the time you've built up enough strikes on an aircraft to disintegrate the structure you've probably already wrecked another vital component of the aircraft -- especially with rifle-calibre bullets.

So in this case when your thin-gauge aluminum can 'see off' more strikes than fabric, that's a plus.

 

[Macandy]

Amen to that. Worst aircraft I have worked on for structural restoration. Lots of small fiddly parts that are in hard to access locations. Access panels were the absolute smallest they could get away with so servicing was also difficult.

Every restoration engineer I've spoken with curses with an absolute vengeance the wing of a spitfire, especially that insanely complex and unrepairable spar, let alone almost every panel on a Spitfire being a compound curvature one...

Its a racing plane wing, but its not being used on a racing plane.

 

[Macandy]

And "scrapped" Spitfires were sent to the nearest factory to be upgraded to the latest model and given a new serial number.
If the wings were perfect they would just get a new serial and new paint job. If not the same as the fuselage - upgrade and reserial.
One of the reasons why no-one knows how many Spitfires were produced.

It also meant that many 'new' Spitfires and Seafires weren't, and as war weary airframes, many didn't deliver the performance they were supposed to on paper and were 'fragile'

 

[EwenS]

Every restoration engineer I've spoken with curses with an absolute vengeance the wing of a spitfire, especially that insanely complex and unrepairable spar, let alone almost every panel on a Spitfire being a compound curvature one...

Its a racing plane wing, but its not being used on a racing plane.

But let's face it, when the Spitfire was designed, no one thought that it would need to be produced through a war for as long as it was. It was a 1934 design. The Spec for the next generation fighter was issued in 1937. And no one expected war in 1939 until much later. So mass production was probably far from R.J. Mitchell's mind.

 

[Deleted member 68059]

I suspect that how good your ground-crews are was a lot more important than which plane you had, with respect to the specific point raised by the original poster
at the start of the thread.

 

[MIflyer]

"No 3 of the section failed to use his armament equipment...."

I was aware that at least some of the fighter aircraft in the BoB were equipped with a battery powered radio, but this was true of the gunsight as well? Was it so hard to wire the sight into the aircraft electrical system that they resorted to batteries that had to be charged?

I realize that people joke about Lucas being the Prince of Darkness, but that's a bit much!

 

[buffnut453]

Every restoration engineer I've spoken with curses with an absolute vengeance the wing of a spitfire, especially that insanely complex and unrepairable spar, let alone almost every panel on a Spitfire being a compound curvature one...

Its a racing plane wing, but its not being used on a racing plane.

What does this have to do with operational sustainability? Ground crew on Spitfire squadrons weren't hand-crafting new panels. They were applying approved repair techniques and replacing components either from stores or by cannibalizing hangar queens.

Regarding the wing spar, again, if ANY wing spar in ANY aircraft is damaged then the wing is replaced. Squadrons do NOT repair wing spars because there may be unseen consequences to the spar damage that make the aircraft dangerous to fly. It's much easier to unbolt the damaged wing and replace it with a spare. That capability is clearly shown in the Spitfire photos I posted earlier.

 

[buffnut453]

It also meant that many 'new' Spitfires and Seafires weren't, and as war weary airframes, many didn't deliver the performance they were supposed to on paper and were 'fragile'

Any manual production line will deliver lemons (Friday afternoon or otherwise).

If you're suggesting that remanufactured Spitfires resulted in a greater number of lemons than other aircraft types, then please provide your source and/or data to back up your claim.

I really wish you'd actually engage in conversation instead of making pronouncements and then ignoring the responses. That's rather troll-ish behavior.

 

[FLYBOYJ]

The test is perfectly valid -- my inference is the issue.

How is the test valid when you cannot asses the damage to the airframe with those "deflections," and if they incurred an un-airworthy condition?

Aircraft losses due to structure damage seem to make up a low percentage of causes. Generally, I think by the time you've built up enough strikes on an aircraft to disintegrate the structure you've probably already wrecked another vital component of the aircraft -- especially with rifle-calibre bullets.

What are those percentages? Your assumption is a "dynamic guess" because you cannot predict this scenario or accurately gather data on this in the aftermath of the aircraft being brought down.

So in this case when your thin-gauge aluminum can 'see off' more strikes than fabric, that's a plus.

Possibly, there's many assumptions considering that on "metal aircraft," some of the structural load will be carried by the skin where on a fabric aircraft (or partial fabric aircraft like the Hurricane) strikes can "possibly" go right through the assembly.

 

[FLYBOYJ]

It also meant that many 'new' Spitfires and Seafires weren't, and as war weary airframes, many didn't deliver the performance they were supposed to on paper and were 'fragile'

First do you have evidence of this? And what's YOUR definition of "war weary?"

 

[Shortround6]

The British did do quite a bit of testing on old airframes (or crash damaged) but many tests may have been run for specific purposes. Like seeing how many rounds it took to set fire to a fuel a tank. Or if they needed to increase the thickness of a piece of armor.

In such cases the distribution (direction and location) of the shots that failed to hit the intended test target component may not have been recorded. Tracking down all the deflected bullet paths would be a lot more work.

 

[MikeMeech]

The British did do quite a bit of testing on old airframes (or crash damaged) but many tests may have been run for specific purposes. Like seeing how many rounds it took to set fire to a fuel a tank. Or if they needed to increase the thickness of a piece of armor.

In such cases the distribution (direction and location) of the shots that failed to hit the intended test target component may not have been recorded. Tracking down all the deflected bullet paths would be a lot more work.

Hi
There were a lot of trials during 1938, many of these are described in 'Knights of the Skies, Armour protection for British Fighting Aeroplanes' by Michael C Fox, in his section on 'The Inter-War Years'. It includes trials on certain items as you mention eg. armour plate, fuel tank etc, also for example the effects of a 37mm cannon on metal wings and the effects of a 20mm HE shell on a running engine:

Also tested against 'whole aircraft' structures like the Hawker hart fitted with armour plate (plus dummy crew and equipment) checking damage to the aircraft structure and armour plate, and how the strikes were deflected:

The Blenheim I underwent a number of tests:

As did the Hurricane:

These were in part to check how effective armour plate, bullet proof windscreens, dural sheets and the general aircraft structure was at stopping or dissipating the rounds of various calibres that were fired at the target.
So the RAF was engaged in some trials, I would suggest that reading the book may be quite useful for those interested.

Mike

 

[pbehn]

Every restoration engineer I've spoken with curses with an absolute vengeance the wing of a spitfire, especially that insanely complex and unrepairable spar, let alone almost every panel on a Spitfire being a compound curvature one...

Its a racing plane wing, but its not being used on a racing plane.

In the BoB when a Spitfire was damaged so badly they couldnt be repaired on the airfield, they didnt ask restoration engineers in USA to do the repairs. They were sent to places that repaired Spitfires, only Spitfires, and the people were quite proficient in repairing Spitfires, Hurricanes were repaired elsewhere if needed. The outer section of a Hurricane wing could be replaced in hours by a few men, which is a huge advantage, but the Spitfire wing, which gave it the highest critical mach number of any WW2 piston powered plane was why it was a success as a front line fighter throughout the war and the Hurricane wasnt. BTW that easy to repair Hurricane wing contained a fuel tank that turned the plane into a torch in 2 seconds.

 

[MiTasol]

Hi
The book 'Airframe Construction and Repair' by John T Henshaw, Pitman 1943, has information on repairing tubes:
View attachment 682430
View attachment 682431
View attachment 682432
View attachment 682433
Also 'quick' release fasteners for access panels were common, these are from my own technical training notes from the early 1970s, but on the whole in use by WW2:
View attachment 682434

The Amal, for instance, was used on the Hawker Typhoon and other Hawker aircraft, the Fairey was used on the Spitfire, but also they were used on interwar aircraft.

Mike

Hi Mick
Good very basic reference but first option always is what is specified in the manufacturers manuals - in this case

If major load carrying components of the fuselage assembly are damaged and the assembly needs to go in a jig, it might be more economical to scrap the aircraft but without a detailed hidden damage inspection, your assessment is a very wild guess to say the least. To say a P-40 "would have" faired better is even a wilder guess!

 

[FLYBOYJ]

Hi Mick
Good very basic reference but first option always is what is specified in the manufacturers manuals - in this case

Exactly!

 

[Greyman]

How is the test valid when you cannot asses the damage to the airframe with those "deflections," and if they incurred an un-airworthy condition?

What are those percentages? Your assumption is a "dynamic guess" because you cannot predict this scenario or accurately gather data on this in the aftermath of the aircraft being brought down.

Possibly, there's many assumptions considering that on "metal aircraft," some of the structural load will be carried by the skin where on a fabric aircraft (or partial fabric aircraft like the Hurricane) strikes can "possibly" go right through the assembly.

The test was to determine if the 4-mm plate behind the pilot was adequate, it wasn't an overall vulnerability trial. What happened to bullets that were deflected away from striking the plate was immaterial.

Re: percentages, the best I've seen is from a RAND study (behind a paywall unfortunately) discussed a bit here: Location of flak damage . Luckily I was able to copy down some of the findings when I came across them ages ago.

Different aircraft, different point in time -- but aircraft structure was the area hit most often at 43%, but was the cause of only 11% 12% losses (EDIT: of single-engine types). On top of that, these were all USN radial types, aircraft with coolant systems would have that structure-loss-percent pushed down even further.

Similar British reports 'ANALYSIS OF CAUSES OF ENEMY AIRCRAFT CRASHES IN GREAT BRITAIN' aren't as detailed as the above US report but it's clear 'structure damage' is a low percentage cause.

 

[PAT303]

It also meant that many 'new' Spitfires and Seafires weren't, and as war weary airframes, many didn't deliver the performance they were supposed to on paper and were 'fragile'

All repairable Spitfires were sent to the Civilian Repair unit for a factory thorough repair, no ''war weary'' planes left the unit, they were either rebuilt to factory standard or were scrapped. Every Spitfire, I'll repeat it, EVERY Spitfire was test flown whether it was new or rebuilt to garantee it met the acceptable standards for speed, climb, dive and turn performance before being accepted into service, there is plenty of evidence of war weary planes needing TLC, rubbing them down and repainting to restore the finish was common but battle scars and chipped paint has to be expected on front line fighters.

 

[FLYBOYJ]

The test was to determine if the 4-mm plate behind the pilot was adequate, it wasn't an overall vulnerability trial. What happened to bullets that were deflected away from striking the plate was immaterial.

OK "striking plate" (as in armor) not actual aircraft structure as first mentioned?

Re: percentages, the best I've seen is from a RAND study (behind a paywall unfortunately) discussed a bit here: Location of flak damage . Luckily I was able to copy down some of the findings when I came across them ages ago.

Different aircraft, different point in time -- but aircraft structure was the area hit most often at 43%, but was the cause of only 11% 12% losses (EDIT: of single-engine types). On top of that, these were all USN radial types, aircraft with coolant systems would have that structure-loss-percent pushed down even further.

A better way to gain analysis as you're physically inspecting the aircraft, but this indicates flack damage, not damage from air to air combat.

Similar British reports 'ANALYSIS OF CAUSES OF ENEMY AIRCRAFT CRASHES IN GREAT BRITAIN' aren't as detailed as the above US report but it's clear 'structure damage' is a low percentage cause.

Is it? I see no consideration for the "type" of crash (and correct me if I'm wrong). Is this determination considered for aircraft that burnt upon impact? Hole in the ground? Augured in, "creamed" or broke up in the air due to excessive structural loads? I doubt it...

I'll be honest, I'm not necessarily disagreeing but in a combat situation you're never going to get an accurate assessment of this unless you're going to get enemy gun camera footage to see what actually brought down said aircraft, I doubt that was ever going to happen.

 

[Greyman]

OK "striking plate" (as in armor) not actual aircraft structure as first mentioned?

I'm a bit lost now.

• They were testing the seat armour in situ.
• Damage caused to the aircraft wasn't a concern -- just the plate.
• Interference from aircraft structure as the bullet traveled to the armour was noted (deflections, fragmentation, etc.)
• The Spitfire's skin was noted as reason it had more deflections than the Hurricane

A better way to gain analysis as you're physically inspecting the aircraft, but this indicates flack damage, not damage from air to air combat.

Is it? I see no consideration for the "type" of crash (and correct me if I'm wrong). Is this determination considered for aircraft that burnt upon impact? Hole in the ground? Augured in, "creamed" or broke up in the air due to excessive structural loads? I doubt it...

I'll be honest, I'm not necessarily disagreeing but in a combat situation you're never going to get an accurate assessment of this unless you're going to get enemy gun camera footage to see what actually brought down said aircraft, I doubt that was ever going to happen.

Reluctant Poster's post at the end of the thread (#17) seems to indicate the figures I had were for damage from enemy aircraft.

The British data is lot 'messier' -- as you suspect; a lot of 'cause not ascertainable' and more vague causes like 'broke up in the air' (tail shot off? overstressed airframe with a dead pilot? who knows). But when they could be ascertained ... coolant, engine, and fuel systems were cause for the great majority of losses (just looking at 109s in this case). As I mentioned earlier it generally backs up what the RAND study had (the main difference being the big percentage of coolant system losses over England).