Special High Altitude Spitfires

[M20gull]

Well, I said in this Aboukir thread that I would try and summarise in one place what I had found about the various special high flying Spitfires in RAF service.  I didn't realise how absorbed I was going to get and I suspect that I might be spending a lot more time on this than I intended.  Basically every time I read something to extract some detail I find another interesting story!  So I will set out what I have found so far and add to it if I come across anything interesting.

 

I'm no expert on modelling or Spitfires and will certainly update stuff when I'm challenged.  I only model Spitfires and, being a bit old, my skills are not the best but are getting better.  When I started modelling again I said I would not correct mistakes, just learn from them and so far I have stuck to that.  With what I now know my earlier attempt at BR114 has a load of mistakes; the next attempt will be better!

 

I have learned a lot from this forum and hope it continues.  I'm not sure I'm going to present anything new but who knows?

 

I've divided the work in to the following parts:

1. The Vs and VIs operated by 103MU
2. The IXs operated by 103MU
3. IXs attached to 1 squadron SAAF
4. Natural Metal Finish 'SAAF' IXs in 1944
5. Northolt SS Flight

 

I'm going to leave Northolt until after I have seen the article in next month's SAM.  I found this month's very interesting.  It has not made me change my mind about the colours I have used and reinforced the point regularly made here that you should be confident in your choices when interpreting colours and respect other people's choices.  I won't be posting photos but will link to them where appropriate.  I also won't be quoting very much from Paul Lucas's article; I don't want to stop you buying SAM.

[M20gull]

The background for the North African Spitfires is the reconnaisance threat offered by German planes flying out of Crete, especially the Ju86 P2.  The database on this link shows that the JU86s operated from June 42 to October 43 and then again from April to October 44.  I would point out:

• only 2 JU86s are shown as lost to enemy action; this is less than the number of claims but that is far from unusual!
• there are six losses not due to enemy action
• just because they have some in service does not mean they are serviceable; this seems to have been a persistent issue for the Ju86s and Ju88s
• they are shown as R1s but Wiki suggests that R1s only existed as prototypes. Plenty of other sources suggest they should be P2s

[M20gull]

A quick aside:

 

Wendel Nelson was reportedly the OC of the High Altitude Flight at 103 MU in Aboukir.  I've ordered copies of the 2009 Flypast magazines that cover his story but there is a hint of it here and details of his final accident here.

 

As might be expected from pilots involved in flying special aircraft there are some interesting background stories!

[M20gull]

I have been making maximum use of the National Archives allowing access to the Squadron Operation Record Books.  Sadly the 103MU one is not digitised.  However, every reference I have seen suggests that there is not a great deal of data there anyway.  Given how regimented the RAF is, I was surprised at the variability of the content of the ORBs  They are still a great read, especially for the fairly idle squadrons around the Nile Delta as they are much more than just a list of operations!  Mostly moaning about not being involved in the fighting.

 

A big handicap for modelling is the small number of aircraft and the inherently small number of photographs.  While the story would make a great Osprey book (as suggested by someone else) it would not have many pictures in it!

 

Turning to some aircaft:

 

Spitfire Vs start appearing in the Middle East in the first half of 1942, mostly arriving by the Takoradi route (see this link for a description).  This forum post suggests that the Mk Vs were successfully used by 103 MU from June to October.  I did find (but have mislaid the reference) a discussion where the grandson of one of the 103MU mechanics was adamant that there was only one plane modified, but this cannot be the case for reasons that become obvious.  Three airframes are usually considered as part of this  series:

 

BP985 (no photo) - departed Britain on 9-5-42 on SS485.  The Spitfire database has this arriving in the Middle East 1-8-42 but this is presumably just a reallocation as it looks like it was intended for forwarding to India

BR114 (lots of photos) - departed Britain on 4-5-42 on SS Alderamin (actually left Liverpool on 12-5-42 according to convoyweb arriving in Freetown on 30-5-42) and arrived Middle East  on 26-06-42

BR234 (no photo) - was on the Nigerstown (originally scheduled for Australia see here) and left Britain on 26-06-42 arriving in Freetown on 2-7-42.  This is shown as Middle East 1-8-42 which seems plausible by the time it is forwarded to Takoradi, assembled, tested, ferried to Cairo, re-fettled and released to a unit.  Other aircraft do arrive earlier though.

 

Of these three only BP985 looks like a contender for the 26-6-42 and 27-6-42 interceptions.  I wonder whether these first attempts were actually with unmodified Vs?

Edited March 20, 2021 by M20gull
Typo

[Graham Boak]

13 hours ago, M20gull said:

• only 2 JU86s are shown as lost to enemy action; this is less than the number of claims but that is far from unusual!
• there are six losses not due to enemy action

It is also true that (worldwide) not all damage due to enemy action is actually noticed as being so at the time.  I think a closer look at some of these losses might be interesting.  This is based on a vague memory from another article describing these flights from the German point of view.  Not sure where - possibly Aero Journal?  If memory is correct, at least one of these losses can be linked to a claimed interception.  However, it is equally true that non-combat losses equal or even exceed combat ones, even with types closer to the boundaries of technical knowledge than these Junkers.

[M20gull]

On 16/02/2021 at 10:58, Graham Boak said:

It is also true that (worldwide) not all damage due to enemy action is actually noticed as being so at the time.  I think a closer look at some of these losses might be interesting.  This is based on a vague memory from another article describing these flights from the German point of view.  Not sure where - possibly Aero Journal?  If memory is correct, at least one of these losses can be linked to a claimed interception.  However, it is equally true that non-combat losses equal or even exceed combat ones, even with types closer to the boundaries of technical knowledge than these Junkers.

The Reynolds claim on 24-8-42 is treated by the Germans as ditching due to engine failure.  The line is that the engine problem occurred before they saw the Spitfire, no firing or hits were observed and therefore it's engine failure.  Reynolds version is he fired and then there was more smoke.  We will never know the truth.

 

Correction:  The ditching is on 29-8-42 and coincides with an attack by Genders for which he did not lodge a claim.

 

Lesson for me: Don't fire from the hip using your phone.  Go back and check references on the computer first.

Edited February 17, 2021 by M20gull
Correction

[M20gull]

The modifications to these first Spitfires are pretty well documented:

• Removal of all armour-plating, including the windscreen
• Removal of the existing armament and replacement with 0.5" Brownings in the cannon bay
• Removal of the Vokes filter and replacement with an Aboukir filter
• Increased compression ratio (I think this would be easiest to acheive by skimming the cylinder heads rather than adjusting the block)
• Increased oil tank with deeper cowl (I missed this on my model of BR114)
• The rudder bar was cut in half
• Additional heating with a pipe from the exhaust 
• Extended wing tips
• Four blade prop

These last two mods are usually associated with the shipment of Mk VI Spitfires but they do not leave Britain until 9-9-42, so that cannot be where they came from at this stage.  I will address the VIs later.  The extended wing tips are not standard and I think they do not have lights in them.

 

Then the radio and radio mast was removed from the Striker version and a smaller battery installed.  This means operating with a radio-equipped Marker to coordinate the interception.

 

One further modification that is mentioned in the Aeroplane Spotter article of October 1946 is that "protruding lengths of nuts through bolts were cut off".  I assume that this is just the wrong way round and the bolts were shortened.  The poster whose grandad worked at 103 suggested that main bolts were taken out but this approach seems more realistic.

 

I have seen suggestions that operationally they flew with a reduced fuel load (which might explain the loss of Genders' aircraft) and dispensed with Mae West and dinghy (which does not explain his swim home).  

 

Apart from the photos of BR114 there is no way of knowing which mods were applied when.

[M20gull]

I've found the link to the discussion with the mechanic's grandson: https://ww2aircraft.net/forum/threads/aboukirs-high-altitude-spitfire-original-modification.46460/

[Denford]

40 minutes ago, M20gull said:

The modifications to these first Spitfires are pretty well documented:

• Removal of all armour-plating, including the windscreen
• Removal of the existing armament and replacement with 0.5" Brownings in the cannon bay
• Removal of the Vokes filter and replacement with an Aboukir filter
• Increased compression ratio (I think this would be easiest to acheive by skimming the cylinder heads rather than adjusting the block)
• Increased oil tank with deeper cowl (I missed this on my model of BR114)
• The rudder bar was cut in half
• Additional heating with a pipe from the exhaust 
• Extended wing tips
• Four blade prop

These last two mods are usually associated with the shipment of Mk VI Spitfires but they do not leave Britain until 9-9-42, so that cannot be where they came from at this stage.  I will address the VIs later.  The extended wing tips are not standard and I think they do not have lights in them.

 

Then the radio and radio mast was removed from the Striker version and a smaller battery installed.  This means operating with a radio-equipped Marker to coordinate the interception.

 

One further modification that is mentioned in the Aeroplane Spotter article of October 1946 is that "protruding lengths of nuts through bolts were cut off".  I assume that this is just the wrong way round and the bolts were shortened.  The poster whose grandad worked at 103 suggested that main bolts were taken out but this approach seems more realistic.

 

I have seen suggestions that operationally they flew with a reduced fuel load (which might explain the loss of Genders' aircraft) and dispensed with Mae West and dinghy (which does not explain his swim home).  

 

Apart from the photos of BR114 there is no way of knowing which mods were applied when.

Not mentioned, but as all interceptions took place by day, all lights and anything associated with them eg wiring, fuses, switches were removed too.

[Dave Swindell]

1 hour ago, M20gull said:

The modifications to these first Spitfires are pretty well documented:

• Removal of the existing armament and replacement with 0.5" Brownings in the cannon bay
• Removal of the Vokes filter and replacement with an Aboukir filter
• Increased compression ratio (I think this would be easiest to acheive by skimming the cylinder heads rather than adjusting the block)
• Increased oil tank with deeper cowl (I missed this on my model of BR114)
• The rudder bar was cut in half
• Additional heating with a pipe from the exhaust 

Comments below based on the airframes you're discussing being built and delivered as VC or VC(Trop)

• Replacement 0.5" Brownings presumably fitted in place of 20mm cannon, as they wouldn't fit in place of the 0.303's, and the cannon position would already have strengthened mounting positions.
• Increased compression ratio would be easiest by skimming the heads, reducing the head gasket thickness or a combination of both, and wouldn't necessarily require an engine change to accomplish - if spare heads were available these may have been prepared in advance and "service exchanged". 
• The increased oil tank and deeper cowl is standard V(Trop), not a modification, and is noticeable on any V(Trop) that has had the Vokes filter changed to an Aboukir filter eg photo's of Widge Gleed's IR@G and accompanying 601 VB's.
• Not sure what you're referring to when you say the rudder bar was cut in half, could you expand any more on that?
• Additional heating with a pipe from the exhaust, not a modification, standard VC feature for heating the outer MG bays. If these guns were removed and weight saving was the order of the day I'd suggest that this was a feature that was removed, not added. When the pipework was removed (at least partially, if not fully) the tube through the exhaust stacks was usually retained, but the pipe disappearing inside the cowling aft of the exhaust was removed and the hole in the cowling blanked with a small plate on the inside of the panel. The pipework in the engine bay could be removed, and I'd guess the same for the pipework in the MG bays, but I suspect the pipes in the wing leading edge would remain in place as they'd be difficult to remove without detaching the wings from the fuselage. Heating for the 0.5" guns if required would be supplied via the normal heating arrangement for the cannons from the radiator exhaust.

[Graham Boak]

It might be worth adding here that at some stage the Mk.Vc going overseas were generally powered by the high-altitude rated Merlin 46 rather than the earlier M45.  This required the return of the small blister on the starboard cowling previously seen on the Spitfire Mk.II because of the Coffman starter on that variant.  It might be interesting to see if any of the photos of these Special Spits show this blister.

 

Edited to clear ambiguity: it was the Mk.II that had the Coffman starter.

[FinnAndersen]

13 minutes ago, Graham Boak said:

It might be worth adding here that at some stage the Mk.Vc going overseas were generally powered by the high-altitude rated Merlin 46 rather than the earlier M45.  This required the return of the small blister on the starboard cowling previously seen on the Spitfire Mk.II because of the Coffman starter on this variant.  It might be interesting to see if any of the photos of these Special Spits show this blister.

Not BR114, as far as I can see

 

/Finn

 

[M20gull]

@Dave Swindell

• Oil tank - cannot believe I wrote that as I knew the oil tank was standard for the Tropical Vs
• Rudder bar - I don't know any more - it is mentioned in the Aeroplane Spotter article.  I wonder if there is part of the bar that could be removed at the expense of pushing harder or just accepting that for the interceptor role drastic rudder movements were unlikely
• Heating pipe - this is visible in the Aeroplane Spotter article above the exhaust and in this photo.  It made me think that it might be used for additional cockpit heating given the low temperatures at altitude

[FinnAndersen]

49 minutes ago, M20gull said:

• Rudder bar - I don't know any more - it is mentioned in the Aeroplane Spotter article.  I wonder if there is part of the bar that could be removed at the expense of pushing harder or just accepting that for the interceptor role drastic rudder movements were unlikely

Spitfires did not have a rudder bar as such, so this seems as a story that has been "modified" at some point.

 

I wonder what the original idea was; perhaps the adjustment part of the rudder pedal was deleted?

 

Some of the modifications I've heard about  was a bit drastic and perhaps marginal, like the deletion of wires and fixtures of navigation and recognition lights.

 

On the other hand, every pound and ounce left on the ground counted.

 

/Finn

[M20gull]

15 minutes ago, FinnAndersen said:

Spitfires did not have a rudder bar as such, so this seems as a story that has been "modified" at some point.

 

I wonder what the original idea was; perhaps the adjustment part of the rudder pedal was deleted?

 

Some of the modifications I've heard about  was a bit drastic and perhaps marginal, like the deletion of wires and fixtures of navigation and recognition lights.

 

On the other hand, every pound and ounce left on the ground counted.

 

/Finn

"Fanciful" is a word I have seen used to describe that article but the other modifications do seem to be corroborated. Now I have looked at the rudder there is not much you could remove, maybe just the upper pedals.

[malpaso]

I wonder if they chose the skinnier, smallest pilots and sent them up just in shorts for ultimate weight reduction?  🤣

[M20gull]

Another aside: Someone has Genders' log book covering this period

[Denford]

2 hours ago, M20gull said:

@Dave Swindell

• Oil tank - cannot believe I wrote that as I knew the oil tank was standard for the Tropical Vs
• Rudder bar - I don't know any more - it is mentioned in the Aeroplane Spotter article.  I wonder if there is part of the bar that could be removed at the expense of pushing harder or just accepting that for the interceptor role drastic rudder movements were unlikely
• Heating pipe - this is visible in the Aeroplane Spotter article above the exhaust and in this photo.  It made me think that it might be used for additional cockpit heating given the low temperatures at altitude

When I wrote that anything associated with lighting was removed, I should have said 'presumably removed' but not sure now how to correct earlier postings!

Participants to this thread must judge for themselves whether the the rear view shown in the link must judge for themselves whether the light on the rudder is missing or not.

[Denford]

5 hours ago, M20gull said:

The modifications to these first Spitfires are pretty well documented:

• Removal of all armour-plating, including the windscreen
• Removal of the existing armament and replacement with 0.5" Brownings in the cannon bay
• Removal of the Vokes filter and replacement with an Aboukir filter
• Increased compression ratio (I think this would be easiest to acheive by skimming the cylinder heads rather than adjusting the block)
• Increased oil tank with deeper cowl (I missed this on my model of BR114)
• The rudder bar was cut in half
• Additional heating with a pipe from the exhaust 
• Extended wing tips
• Four blade prop

These last two mods are usually associated with the shipment of Mk VI Spitfires but they do not leave Britain until 9-9-42, so that cannot be where they came from at this stage.  I will address the VIs later.  The extended wing tips are not standard and I think they do not have lights in them.

 

Then the radio and radio mast was removed from the Striker version and a smaller battery installed.  This means operating with a radio-equipped Marker to coordinate the interception.

 

One further modification that is mentioned in the Aeroplane Spotter article of October 1946 is that "protruding lengths of nuts through bolts were cut off".  I assume that this is just the wrong way round and the bolts were shortened.  The poster whose grandad worked at 103 suggested that main bolts were taken out but this approach seems more realistic.

 

I have seen suggestions that operationally they flew with a reduced fuel load (which might explain the loss of Genders' aircraft) and dispensed with Mae West and dinghy (which does not explain his swim home).  

 

Apart from the photos of BR114 there is no way of knowing which mods were applied when.

A point not so far mentioned is that the photo in the (Aeroplane Spotter) article shows the fuselage roundel being of the B type.  All others of BR114 show the 'standard' C1 type.  Curious: perhaps the photo was not, as the article supposes, of BR114 but another of those modified....

[M20gull]

11 hours ago, Denford said:

A point not so far mentioned is that the photo in the (Aeroplane Spotter) article shows the fuselage roundel being of the B type.  All others of BR114 show the 'standard' C1 type.  Curious: perhaps the photo was not, as the article supposes, of BR114 but another of those modified....

I think it is BR114 for a number of reasons but it is only speculation. 

Morgan and Shacklady claims that BR114 is named "Irene" and I think that there is a script on the fuel tank cover consistent with that name.

Secondly the production database has a Ops Cat B on 13-9-42, i.e. after the Ju86 claims. This suggests to me that it needed some repair and that may have required a repaint.  That is reinforced in my mind as the later group of photos, which because they include VIs must be November or later, show BR114 in 'b' pattern that should not have been there originally.  These later photos also do not have the "Irene".

Edited February 17, 2021 by M20gull
Posting from phone; remembered a wrong reference

[M20gull]

Next I want to look at more references in the production database for two of these:

 

BR114 - the database has "Crosby Co" 23-3-42 before the plane leaves the UK and "mods" immediately after.  "Crosby Co" appears on 78 Mk Vs but I have not been able to find any more information online.

 

BR234 - the database suggests that the plane has a Merlin 61 fitted.  As this one was destined for Australia this modification, if correct, must have been made in Africa, presumably at 103 MU.  I cannot see why you would ship a Merlin 61 to Aboukir with its associated spares.  Why not just ship a IX?   I guess there is no way of knowing the truth here.

[Denford]

13 hours ago, malpaso said:

I wonder if they chose the skinnier, smallest pilots and sent them up just in shorts for ultimate weight reduction?  🤣

A master at my school was known as 'Jumbo Jennings' on account of his large size.  Was 'Jumbo' Genders so named for the same reason?

[Graham Boak]

Likely: the nickname can be found elsewhere in the RAF at this time.

[Dave Swindell]

Some further observations and thoughts after having a read through the provided links and a closer look at the photos

 

Exhausts:-

Standard exhausts with intensifier gun heating tubes were originally fitted, and at least the section from the exhaust into the cowling (and most likely the rest of the pipework in the engine bay) has been removed.

The stbd side photo clearly shows an external patch on the cowling covering where the pipe had penetrated through it. The forward section of the exhaust may have been replaced with one without the heating tube, the photo isn't clear enough to determine.

The photo from aft shows the open end of the intensifier tube outlet on the rear exhaust stub (ie removed pipework) This photo also shows some sort of small diameter pipe of apparently randomly bent shape above the exhaust stack. The ends of this pipe aren't clear, and there's not a similar arrangement visible on the stbd side.

The photo of the port side shows the forward stub doesn't have the gun heating intensifier tube, so this section at least has been swapped and or modified. The small diameter pipe is again visible, again the ends aren't obvious but one end appears to be in the vicinity of this forward section.

The popular flying text contains a couple of interesting titbits which may be relevant to this pipe. It has been surmised that this may be cockpit heating, but if so is rather small in diameter for this and if correct, wasn't very effective given the mention of a cockpit temperature of 67 below zero. The other titbit is the mention of the fuel boiling at altitude due to drop in atmospheric pressure. One way of mitigating this is to pressurise the fuel system, this was done on later high altitude spitfires by using the exhaust air from the engine fitted vacuum pump, but another source of fuel pressurisation was from exhaust gases, which had the added advantage of fire suppression. I'm guessing here, but the small diameter pipe "might" be an attempt to pressurise the fuel system using exhaust gas from a ram intake to the small diameter pipe in the modified front exhaust stub on the port side. The extended randomly bent section of pipe above the exhaust could be an attempt at cooling the gases en route to the (presumably) modified fuel tank vent system. It would be interesting to see if the standard fuel tank vent was present in the radiator inlet trunking.

 

Compression:- Standard Merlin compression was 6:1, the article notes an increase to 7:1 which is quite a bit. This would have assisted high level performance, but would have required careful engine management to avoid overboosting at low altitude

 

Engine:-

Listed as having an M46 fitted, which had a better high altitude performance than the more favoured M45, which is a logical choice for role. @Graham Boak Alex Lumsden's British Piston Aero Engines doesn't mention the Coffman starter for the M46, it is mentioned for other marks that had it.

 

Wing tips:- whilst these appear to be extended in comparison to standard tips, they're not the pointed tips fitted to later HF Spitfires. They appear to be a more rounded compromise somewhere in between -  local one off mod?

 

Nav lights:- the new wingtips appear to be devoid of nav lights, but the rear shot shows the tail light was still fitted.

 

Canopy: - the hood, especially in the rear view, appears to be flat sided, more like a later mk1 canopy rather than what would have been a standard blown hood. Difficult to tell, but it might even be flat topped as well as per early mk1?

 

Windscreen:- if the armoured glass has been removed, the mounting frame for it has been retained (internal) clearly visible in the port side view. Presumably adapted to mount a plain Perspex screen? 

 

Aboukir filter:- this one is in a curved fairing, rather than the square boxy one fitted to Vb's of 601sqn as per the Tamiya kit

 

Oil cooler:- has the enlarged outlet as per optional part in the new Airfix Vc

 

Radio Hatch:- this isn't visible to me in either port side or rear photos, another weight saving measure? All the radio gear including the mounting tray and hatch door removed, then simply plated over? The aerial mast has also been removed.

 

"Main" Bolts:- I rather suspect that this story has lost something in translation / Chinese whispers? Together with the miss-told story regarding the nuts and bolts. There's most likely some truth in there somewhere, and disassembling bolts from the airframe and shortening them to remove any excess projecting beyond the nuts  - and then replacing them - is more likely than removing "main bolts" completely.

 

The Aeroplane Spotter article does seem a bit fantastic in places, eg swimming 40 miles to shore in 21 hours after bailing out does seem a rather remarkable feat, the distance quoted does sound rather fanciful...

[Graham Boak]

The Mk.46 didn't have the Coffman starter - I have corrected my original posting to remove the ambiguity.  However I have seen that there was some other change at the front of the engine for which the small blister was re-adopted.  I'm sorry that I didn't make note of this, but the two Mk.V books I've been reading recently are the new Wingleader one (which lacks reference to the Mk,Vc changes but is otherwise very good indeed) and the Wojtec Matusiak's latest Stratus book on the Polish use of the Mk.V, so I'll bet it is in one of them.  Both well worth buying and reading anyway.