Spitfires with Merlin XX

[RCAFson]

I ran across an interesting paragraph in Price's The Spitfire Story:

"...in 1943 some 50 MkIIs were fitted with the more powerful Merlin XX and operated in the air-sea rescue role as the Mk IIC." (p.109)

I never knew that Spitfires were used operationally with the Merlin XX!

Morgan and Shacklady confirm this on page 108 of Spitfire the History.

 

[tomo pauk]

Didn't someone 'proved' here that installation of the XX on the Spit was as good as impossible?

 

[Aozora]

The main reason the Spitfire III/Merlin XX wasn't manufactured in quantity to replace the Mk II and II, was because the Merlin XX was reserved for the Hurricane II. The follow on was, therefore, the "interim" Mk V. There was no reason the Merlin XX could not be fitted to the Spitfire.

 

[Edgar Brooks]

Except the Merlin 45 (with minimal juggling) could be fitted into the same space as the Merlin III. The Merlin XX couldn't, so the Spitfire (like the Hurricane II) needed to be 4" longer, with all the modifications that entailed, plus consequent alterations to the u/c rake.

 

[Aozora]

Except the Merlin 45 (with minimal juggling) could be fitted into the same space as the Merlin III. The Merlin XX couldn't, so the Spitfire (like the Hurricane II) needed to be 4" longer, with all the modifications that entailed, plus consequent alterations to the u/c rake.

Good point - I guess at the time the decision was made to drop the Spitfire III, the Spitfire was able to cope with the Bf 109 - although the F started to emerge in late October 1940 - and no-one had any idea that the 190 threat would materialise, so it made more sense to expedite both Merlin and Spitfire production by dropping the second stage of the Merlin XX and using an improved single-stage supercharger to develop the Merlin 45. That way it was possible to utilise all the existing Spitfire tooling for the Spitfire V as well as using Merlin XX tooling for the 45. Not forgetting that many the Spitfire III's improvements were incorporated into the Spitfire VC.

 

[Shortround6]

I think you are a bit off on that.

" by dropping the second stage of the Merlin XX and using an improved single-stage supercharger to develop the Merlin 45"

The difference was actually "dropping" the 2 speed supercharger drive of the Merlin XX.

The Merlin XX and 45 both used the same improved supercharger developed by Hooker. The 2 speed drive may have required a different block (crankcase) casting to accommodate it.
The Merlin 46 used a different supercharger.

 

[BiffF15]

Brrrrr.... That just reminds me that winter is still with us..