Interesting bit of Spitfire history….

Welcome back, ‘Mark12’

When you go on holiday, someone has to answer these things!!

I’ve got a copy of the eighteen manual. I’ll have a look and see what it specifies.

Cheers

Bruce

The proposed conversion of Spitfire Mk XIV SM832 to Mk VIII status.

There is more commonality with the VIII and XIV structures than is first apparent. It is easy to view the Mk VIII as a retracting tail version of the MK IX, but that is far from the whole picture. The reason the VIII was late and out of production sequence with the IX was in part due the complexity of the much revised and strengenthed wing – spar webs, wing bolt size, boom reinforcement etc. Indeed apart from the radiators the VIII and XIV wings have very close commonality. It was therefore technically a relatively simple task to convert the high back XIV to VIII status with revised engine pick up machinings and sloping top firewall. Doug Arnold initially saw a commercial advantage to this conversion and traded a package with a certain Seafire owner for a long Merlin bearer, shallow radiators, a Mk IX tail unit and more . He relinquished the original tail unit of SM832 in the trade and only recently this has mated up with the RM694, that has passed up its incorrect Mk IX tail unit. This in turn will now service a Spitfire Mk XII restoration.

Mark

Spitfire XVI TB863 was on the Elstree Studio Lot, circa 1966, wings off, engine out and fitted with the broad chord ‘pointy’ rudder as fitted to XVIs and some late Mk IXs.

Mark

Spitfire Mk XIV rudders.

There is a lot more complexity in the range of Spitfire rudders, utilised during total production, than first meets the eye. Discussing the case in question – Griffon Spitfires Mk XIV, my copy of AP1565T with amendments to 1946 shows just the one fuselage type – high back, and one rudder type, which I call the ‘standard’ type. Period photos from 1945, notably late production survivor TZ138, which is a low back fuselage, is fitted with this ‘standard’ type rudder. Post war export low back Mk XIV Spitfires survivors however, to Belgium, Thailand and India, together with an RAF survivor all appear to have been fitted with what I call the ‘extended tip’ type rudder with a broader chord and incorporating the ‘split trim tab’.
I do not have the AP for the Mk XVIII Spitfire. Although looking apparently identical externally to the low back Mk XIV, the Mk XVIII has many major technical variations including uniquely solid spar booms on the wings, rather than the familiar laminated box section booms as on all other marks. There are also subtle differences in the construction of the stabilisers and the fin is taller by a couple of inches or so. As all Mk XVIIIs were low back fuselage I would conjecture, without access to the relevant technical documents to hand, that the ‘extended tip’ type rudder was introduced on Mk XVIII Spitfires .With presumed improved flight dynamics, and it appears this rudder is interchangeable with the Mk XIV, it would be logical to retrospectively fit them to export low back Mk XIV machines and post war RAF aircraft, as required and at modest cost. It does however require that a packer, made of wood or metal, be fitted to the top of the production Mk XIV fin.
In India, SM832, a high back Mk XIV was fitted with the ‘extended tip’ type rudder and still retains one today for flight although this is not the original tail recovered with this machine from India. I am sure that once exported, rudders could change as available, for display if not for actual flight. I suspect that restorations to low back Mk XIV aircraft in the UK in recent years have had the ‘packer’ incorporated in to the fin sheet metalwork.
Mk XIX survivors, all high back of course, have the ‘standard’ type rudder of the Mk XIV.
To confuse, perhaps, and to extend the discussion, the high back Mk 21, appears to carry the ‘standard’ Mk XIV rudder but the fin has the packer!!

Mark

Originally posted by Bruce
DIGBY has outlined most of the changes you would need to make.

I stand corrected! 😀

As regards the rudders, IIRC, the larger rudder was fitted to the Griffon aeroplanes, as you needed a very heavy foot to control the aircraft on take off, and during high G manouevres. The larger rudder gives better control.

Bruce

The conversion was done when the aircraft was owned by Doug Arnold.

Not sure how far it got, but they did swap the tail unit for an early one, and certainly made a start on converting the front end. DIGBY has outlined most of the changes you would need to make.

When we got it, D ick Meltons boys had already reconverted the front end back to Griffon status, and we finished it off.

Bruce

Change the mount, obviously.

I am, of course, not an aircraft engineer, so I’m only “assuming” as always! 😉

Originally posted by DazDaMan
I dunno if they would have gone as far as all that – there’s likely an easier way by just re-engining and fitting the correct tail surfaces, armament etc.

Seems to me like a similar case with the Buchon/Me109G conversions that abound.

But surely tou would need to change the engine mount and the associated strengthening otherwise the Merlin would fall out of the Griffon mount?

Originally posted by DIGBY
Not forgetting wingspars, frame 5, ailerons, engine mounts from vertical to horizontal, longeron strengtheners remove to fit Merlin bearers, fin, ailerons, wingtips the list goes on and on

I dunno if they would have gone as far as all that – there’s likely an easier way by just re-engining and fitting the correct tail surfaces, armament etc.

Seems to me like a similar case with the Buchon/Me109G conversions that abound.

Must have been major work to convert it into a mk VIII and back again, anyone know how far the conversion got before it was reconverted?

Not forgetting wingspars, frame 5, ailerons, engine mounts from vertical to horizontal, longeron strengtheners remove to fit Merlin bearers, fin, ailerons, wingtips the list goes on and on

Engine mount for a start, relocating the oil tank to the original position under the engine, changing the radiators for Merlin-style ones, changing the tail feathers, prop, armament fit (E-wing to C-wing) etc…

Like changing a Hispano Buchon to a Bf109G, only probably a bit more involved!

This is interesting, I’d heard a rumour some years ago of a XIV being converted into a VIII, surely this would have taken a lot of work to do, anyone have any idea what would be involved?

Spitfire rudders

I just had a look at a couple of pics on my PC of Spitfire XIVs RN201 and SM832, and yes their fins are different! I’ve never noticed that before!

The top of RN201’s fin is narrower on the trailing edge than SM832’s.

Any particular reason for this change?

TFC bought her, so they probably decided to restore it back to XIV condition.

Someone’s bound to be able to tell us! Bruce??

Anyone got any idea why the Griffon to Merlin conversion was not completed?

Originally posted by DazDaMan
How about a Griffon to a Merlin then?

SM832, the Spitfire XIV in the photo, when owned by Doug Arnold, was due to be rebuilt as a MERLIN-engined Spitfire MkVIII!!

This must be why it appears in the MkVIII section of Jeremy Flack’s otherwise very good Spitfire pictorial! Mr. Flack identifies it correctly in the opening pages of the book but then mis-identifies it as a MkVIII later on.

Just to be really pedantic; there are two types of Griffon rudder for 14,18,19 etc.

One is the one shown in the pic of SM832 above

The other is a narrow chord, as fitted to BBMF XIX’s and to RN201 (XIV)

And then theres split trim tabs which are fitted to some but not others. It goes on and on and on!!

Cheers

Bruce

How about a Griffon to a Merlin then?

SM832, the Spitfire XIV in the photo, when owned by Doug Arnold, was due to be rebuilt as a MERLIN-engined Spitfire MkVIII!!