Spitfire and the Merlin 100 series?

[BarnOwlLover2]

I wonder why this wasn't considered, aside from the fact that the first Griffon powered Spitfires came before the Merlin 100 was fully developed. The Merlin 100 series of course powered the de Havilland Hornet (130 series) most notably, and I believe formed the basis of the Packard V-1650-9/11/23/25 that powered the P-51H Mustang and the XP-82/F-82B Twin Mustangs. I think that if it was workable, a Merlin 100 powered Spitfire would've been an interesting proposition.

Only thing is that, like the Griffon versions, fuel capacity would've had to have been increased, since the Merlin 100s were capable of making about 300+hp more than the Merlin 60 series engines. Not to mention that more power does also usually mean more strengthening, which generally means that the resulting aircraft will be somewhat heavier, though the power should hopefully offset that.

But I do wonder why this wasn't seriously pursued in war time (I'm betting that some Spitfires flying today are using later engines based on the 100 series that were sold commercially), aside from the fact that the Griffon Spits took the lead in development terms after the Mk IX and Mk VIII were developed.

 

[pathology_doc]

I remember reading a list of reserved and unused Spitfire Mark numbers, some of which were set aside for Merlin developments - possibly with the Spiteful wing. Now I can't find it for the life of me. Potentially some of those might have had Merlin 100s.

But I do wonder why this wasn't seriously pursued in war time

I remember reading somewhere an article entitled "There is no substitute for cubic inches", which if I haven't got my articles mixed up basically made the point that with all else being equal, the bigger engine will win. RR and Supermarine had a guaranteed road to 2000-plus horsepower with the Griffon and as much airspeed as the Spitfire or Spiteful airframe was reasonably capable of.

In any case, the writing was on the wall for prop fighters and everyone knew it, not to mention that the Tempest/Fury family was arguably the better final-generation prop fighter than either the late-model Spitfire or the Spiteful. The Sea Fury might not quite be able to catch a Seafang on published figures, but the Seafang was such a dog with so many development issues that the Royal Navy stuck with the Griffon Seafire all the way out to Korea. (And the only reason prop fighters hung on so long in the fleet is because of the issues early jets had with time in the air, slow acceleration out of the wave-off, etc.)

 

[DWG]

I remember reading a list of reserved and unused Spitfire Mark numbers, some of which were set aside for Merlin developments - possibly with the Spiteful wing. Now I can't find it for the life of me. Potentially some of those might have had Merlin 100s.

If you assume the Griffon Seafire Mks XV and XVII fit in the main Spitfire sequence*, and allow for the first two Griffon Spitfires temporarily being designated Mk 20, then the only hole left is Mk 23. Of course you then have Mk 25 and up to allocate as desired. (I was coincidentally looking at exactly this last night).

* It's pretty clear the Seafire Mark numbering system changed twice, first the Merlin Mks I, II and III, then the Griffon Mks XV and XVII, too neatly matching the gaps in the Spitfire sequence, and then finally Mks 45, 46 and 47.

 

[Foo Fighter]

I have only recently started to see comments on vulnerability of the Spitfire wing, so, what is the 'skinny?

Squadron leader Martindale nearly had the wings ripped of hi PR XI (April 1944) but that was a high speed test flight at approximately 620mph.

What next?

 

[Nik]

Was there a weight & c/g issue, such a 'Spitfire' body would need significant re-balancing, but others were either designed-in or, being a 'twin', more tolerant ?

As I understand it, some-what easier to re-position engine 'pods' to/fro on wings than if nose-mounted...

 

[pathology_doc]

the only hole left is Mk 23

I've read in a few places that that one was going to be allocated to a mark with a different, high-speed (but not laminar-flow) section. IIRC the wing was test-flown but production was not proceeded with. Shacklady's massive tome on the Spitfire has a few details on it; I have the book at home, and can go digging for that tonight if you like.

 

[DWG]

I've read in a few places that that one was going to be allocated to a mark with a different, high-speed (but not laminar-flow) section. IIRC the wing was test-flown but production was not proceeded with. Shacklady's massive tome on the Spitfire has a few details on it; I have the book at home, and can go digging for that tonight if you like.

I'd be interested to hear that, but don't look it up just for me. I was producing a list of production Marks vs engine vs date in service for my own interest, so Mk 23 falls outside that.

 

[EwenS]

From Morgan & Shacklady via Wiki

Mk 23 (type 372)​

The Mk 23 was to be a Mk 22 incorporating a revised wing design which featured an increase in incidence, lifting the leading edge by 2 inches (51 mm). It was hoped that this would improve the pilot's view over the nose in flight and increase the high speed and dive performance of the aircraft. The modified, hand-built wing was first fitted to a Mk VIII JG204 which was tested from July 1944. However the tests were disappointing and, after discussions at Supermarine, it was decided to build a new prototype using the Mk 21 prototype PP139: in this form the prototype was designated F Mk 23, and was to be renamed the Supermarine Valiant. However the new wing gave less than perfect handling characteristics and so the Mk 23 was never built from the Mk 22 airframe as intended.[49]


JG204 history

Spitfire pilots and aircraft database -

PP139 history

Spitfire pilots and aircraft database -

 

[Schneiderman]

Surviving drawings for the Type 372 tell a somewhat different story. There are no GA drawings (can't locate the side view in M & S) and the key wing drawing appears to have been mislaid, but not lost. However there are a reasonable number of preliminary layout ideas, which I have combined in the image below. It would appear that they intended a clean wing as the radiator has been moved below the fuselage, Napier Racer/Mustang style, also the air intakes moved to the front of the wing fillets. No mention of the name Valiant

 

[Foo Fighter]

Great discussion, thanks for educating me, one of my favourite topics.

Given enough data a 3d model sometime, might be in the offing.

 

[Schneiderman]

Surviving drawings for the Type 372 tell a somewhat different story.

Just for the record the drawings on which this was based are
37227 sht2
37238 sht1
37238 sht10H
37295 sht3G

 

[royabulgaf]

If you assume the Griffon Seafire Mks XV and XVII fit in the main Spitfire sequence*, and allow for the first two Griffon Spitfires temporarily being designated Mk 20, then the only hole left is Mk 23. Of course you then have Mk 25 and up to allocate as desired. (I was coincidentally looking at exactly this last night).

* It's pretty clear the Seafire Mark numbering system changed twice, first the Merlin Mks I, II and III, then the Griffon Mks XV and XVII, too neatly matching the gaps in the Spitfire sequence, and then finally Mks 45, 46 and 47.

The 23 was a paper project. Oddly there is a Spitfire 25 and 26, 3/4 scale home built kits by an outfit that got permission from BaE, the successor to Vickers/Supermarine to use this. The 30 series was assigned to the Seafang, and the 40 series to Seafire. I have no idea what Marks 40-44 were or why they were skipped. I'd love to know what they were or why they were skipped.

 

[DWG]

Surviving drawings for the Type 372 tell a somewhat different story. There are no GA drawings (can't locate the side view in M & S) and the key wing drawing appears to have been mislaid, but not lost. However there are a reasonable number of preliminary layout ideas, which I have combined in the image below. It would appear that they intended a clean wing as the radiator has been moved below the fuselage, Napier Racer/Mustang style, also the air intakes moved to the front of the wing fillets. No mention of the name Valiant
View attachment 732871

Wonder how closely this relates to the Griffon-engined 'Spitfire for the FAA' (1939) illustrated on page 117 of BSP3, which is a gull-winged, fillet-intake, ventral radiator design. And I'm not sure the same couldn't be said for this composite - not sure how definite your information on the wing outline is, but I can definitely see ways to interpret that as a shallow gull-wing.

There's also the vee-tailed 1942 FAA Spitfire derivative (BSP3 P118) to illustrate that Supermarine interest in a fillet-intake, gull-wing, ventral radiator Spitfire derivative was an ongoing interest.

For all the hagiography over the Spitfire's wing, Supermarine seem to have spent a lot of time looking at different wings for it - there's also the angular design for the Type 333 to N.8/39 (BSP3 P108), so we're looking at at least 4 or 5 alternative wings looked at relatively seriously.

 

[Schneiderman]

Wonder how closely this relates to the Griffon-engined 'Spitfire for the FAA' (1939) illustrated on page 117 of BSP3, which is a gull-winged, fillet-intake, ventral radiator design. .....

In 1940 Supermarine established a sort-of special projects group to work on new concepts and niche requirements, such as pressure cabin modification for high-altitude Spitfires. Where there are clear signatures on some of the Type 372 drawings they are those of a member of that group.

From what I have seen Type 372 was purely experimental, the ‘semi-laminar’ wing with raised leading edge to the ‘D’ torsion box, and the bits used in my compilation drawing, and so on, all to be incorporated around a modified Merlin-powered Spitfire VIII. I have seen nothing to suggest that a Griffon-powered Mk21-based aircraft was intended to be included under Type 372 as a Mk23. The previous project, Type 371, was of course for the new wing with Supermarine High Speed 371/1 and 371/2 aerofoil, and the Spiteful.

First thing, the project shown on page 117 of BSP was incorrectly identified by Morgan in the Spitfire tome and I discussed this with Tony Buttler while he was writing ‘Propeller Twilight’. We both concluded that it was Sabre-powered not Griffon. My personal view is that this is likely to be the Type 339, to meet NAD925/39 in 1939, but as I have not been able to locate the original drawings that is not certain. There are, indeed, design similarities with the Type 372, initiated over three years later, but whether that is significant or not I cannot say. The gull wing concept on page 118 is very much like the work of the special projects group; an outline of an idea to prompt discussion rather than a formal submission. Again, I have been unable to locate the original drawings.

The wing for the Type 333 project is interesting not only in the simplified plan form and canted main spar, but also that the fold mechanism is quite different from that proposed for the other naval fighters - it folds leading-edge down while the other are leading edge up

 

[DWG]

In 1940 Supermarine established a sort-of special projects group to work on new concepts and niche requirements, such as pressure cabin modification for high-altitude Spitfires. Where there are clear signatures on some of the Type 372 drawings they are those of a member of that group.

From what I have seen Type 372 was purely experimental

That makes sense if the special project group were the ones working on it. You'd clearly want to know whether the wing performed before even considering a production version.

the project shown on page 117 of BSP was incorrectly identified by Morgan in the Spitfire tome and I discussed this with Tony Buttler while he was writing ‘Propeller Twilight’. We both concluded that it was Sabre-powered not Griffon. My personal view is that this is likely to be the Type 339, to meet NAD925/39 in 1939, but as I have not been able to locate the original drawings that is not certain.

Aha, I'd wondered what was going on with the exhaust stacks being so much lower than usual for a Griffon design!

 

[spicmart]

Surviving drawings for the Type 372 tell a somewhat different story. There are no GA drawings (can't locate the side view in M & S) and the key wing drawing appears to have been mislaid, but not lost. However there are a reasonable number of preliminary layout ideas, which I have combined in the image below. It would appear that they intended a clean wing as the radiator has been moved below the fuselage, Napier Racer/Mustang style, also the air intakes moved to the front of the wing fillets. No mention of the name Valiant
View attachment 732871

That thing looks sleek. Where did you get this from?
Do you mind if I post this in another group?

 

[spicmart]

Tempest/Fury family was arguably the better final-generation prop fighter than either the late-model Spitfire

In which respect? In terms of ACM the Spitfire had only the F8F Bearcat as equal afaik ( and maybe the P-51H as well).

 

[Schneiderman]

That thing looks sleek. Where did you get this from?
Do you mind if I post this in another group?

The answer is in post #11 where I listed the drawing numbers of the Supermarine blueprints I used for the compilation. Yes, go ahead and share on other groups

 

[spicmart]

Surviving drawings for the Type 372 tell a somewhat different story. There are no GA drawings (can't locate the side view in M & S) and the key wing drawing appears to have been mislaid, but not lost. However there are a reasonable number of preliminary layout ideas, which I have combined in the image below. It would appear that they intended a clean wing as the radiator has been moved below the fuselage, Napier Racer/Mustang style, also the air intakes moved to the front of the wing fillets. No mention of the name Valiant
View attachment 732871

This would have rectified the one flaw of the Spitfire which was too much radiator drag making it the best of the super-props.

 

[royabulgaf]

I checked in Morgan and Shacklady to see what they had on the missing Seafire marks. It's complicaated. Broadly, the Seafires XV, XVII, and the unbuilt PRXVIII were to be the Seafires 40, 41, and 42 respectively. They ended up getting XV, etc. as things were worked out wotj the RAF. The language is rather oblique. No explanation of the missing 43 and 44.

 

[Schneiderman]

I checked in Morgan and Shacklady to see what they had on the missing Seafire marks..

M&S are fine on built marks of Spitfire but are a bit vague, and have been found to be occasionally quite incorrect, about unbuilt and more speculative projects.