Turret Fighter Mosquito

[nuuumannn]

Hi everyone, as I have mentioned in the Mosquito unbuilt variants thread, de Havilland did in fact build two Mosquitoes fitted with gun turrets, so the subject doesn't fit within that thread, therefore I have decided to create this thread for relevant information. Very few books and official sources mention the turret fighter Mosquitoes, most devote a paragraph or two to the subject, almost dismissively, but include little detail as to the whys and wherefores. I have been piecing together information on the subject because so little is offered in public, yet it is very much a part of the Mosquito story, if not a commonly explored one.

Accompanying the dearth of text on the turret fighter Mossie paragraphs are often the same images, of the prototype fitted with a dummy turret for aerodynamic trials and a grainy image of the fourth prototype with a Bristol turret fitted, but other than that there has been very little released that show the installation or the general impression of the aircraft. To date, no one has produced a profile of the turret fighter Mosquitoes that I can find and it would be nice to see such a thing. I have located an illustration, included with this thread, of official drawings of the DH.98B as it is named, which I saw on a panel poutside The People's Mosquito stand at a Shuttleworth airshow a couple of years ago.

When I discussed the aircraft with those in the stand, their take was that the drawings were for a defensive position for a bomber variant, despite the title clearly stating the aircraft was a turret fighter, not a bomber. This is where things get a bit murky. Specification F.18/40, which has had mention on this forum was originally written for a fixed gun two-seat night fighter to replace the BP Defiant, dated 10/11/1940, but on 9 December a correction was made in that armament was changed to incorporate a 'dorsal power-operated turret'. Clearly what the Air Ministry considered acceptable armament for a night fighter had changed.

This led me to dig deeper and in a couple of sources, including Buttler's BSP Fighters and Bombers 1935 - 1950 (Midland, 2004) I found reference to de Havilland being asked to examine the spec, even though the firm was not invited to tender to it. The result was the two turret fighter Mosquitoes, the fourth prototype W4053 built at Salisbury Hall and flown from there to Hatfield with the turret fitted on 14 September 1941, and W4073, first flight 5 December from Hatfield. DH also did much research into Mosquitoes fitted with turrets as a result, to discover that a considerable amount of performance was lost as a result of the installation. My understanding was that GDeH was lukewarm to the proposal, not surprisingly.

Anyway, I have written an article for a local aviation magazine and to honour the publisher I won't be reproducing it here, but will include snippets if need be, since I am the copyright holder. If anyone has information or importantly further illustrations of the two turret fighter Mossies, which, after having their turrets removed went on to become the prototype T.III trainers, which again, is very rarely touched on that the T.III prototypes started life armed with gun turrets, please feel free to post here. This is so I can plagiarise your efforts and include it within my own research!

Seriously though, the turret fighter Mosquitoes are elusive additions to the Mosquito story and it would be welcome to produce more information on the subject.

 

[nuuumannn]

As an addition to my opening post, I gained figures and important dates from the story from the extremely informative Mosquito by C.Martin Sharp and Michael J.F. Bowyer (Crecy, 1997), as well as detailed information about the Mosquito variants and Specification F.18/40 from Buttler's British Secret Projects Fighters and Bombers 1935 - 1950 (Midland, 2004) and The British Aircraft Specifications File by K.J. Meekcoms and E.B. Morgan (Air Britain, 1994). Various other sources with images and references to the turret Mosquitoes have come from different published sources on the type and are too numerous to mention here. Living in far away New Zealand means that accessing British archives is beyond my everyday routine, not that I have the finances to do such a thing anyways...

 

[airman]

Cool !

 

[fabulousfour]

A little late, but not too late I hope, here is one of the rare photos showing the Mosquito with a turret.



Source is: Air International 2/1983

 

[Archibald]

"The horror, the horror..."

 

[Calum Douglas]

You can turn any aircraft into a flak-gathering ditch-finder if you try hard enough.

 

[iverson]

I believe that the turret was a requirement for the night fighting role and that this requirement was why a turreted Beaufighter was also considered (and probably why the USAAF P-61 had a turret). The turret was thought necessary for attacking bombers from below, the main tactic used by RAF nightfighters in WW1. In the absence of radar, looking up in search of silhouettes against the sky was almost the only way of spotting intruding aircraft.

If I recall correctly, in his book Night Fighter, C.F. Rawnsley talks about his dismay at finding that the Beaufighter lacked an upward-firing turret, which seemed a very backward step compared to the otherwise inferior Blenheim.

 

[Archibald]

Ah ok I thought it was to turn them into Defiants, you know, like the Skua / Roc abomination. I readily agree that night fighting was an all different matter - without scores of 109s to wipe them out of the sky like Defiants it made some sense.

Even if the thought of a Defiant-ized Mosquito or a Roc-like Beaufighter is still sickening from an aesthetic point of view.

 

[iverson]

Ah ok I thought it was to turn them into Defiants, you know, like the Skua / Roc abomination. I readily agree that night fighting was an all different matter - without scores of 109s to wipe them out of the sky like Defiants it made some sense.

Even if the thought of a Defiant-ized Mosquito or a Roc-like Beaufighter is still sickening from an aesthetic point of view.

What's astonishing to me is that anyone in the UK thought that they needed a turret for firing upward. Their own single-seat night fighters carried fixed, upward-firing guns in WW1, as did their cannon-armed night-fighter prototypes in the '30s.

 

[tallguy]

I know it's a touch off topic but what's the earliest drawing we know of where the mossie is locked in as a design¿

 

[tallguy]

Ah ok I thought it was to turn them into Defiants, you know, like the Skua / Roc abomination. I readily agree that night fighting was an all different matter - without scores of 109s to wipe them out of the sky like Defiants it made some sense.

Even if the thought of a Defiant-ized Mosquito or a Roc-like Beaufighter is still sickening from an aesthetic point of view.

What's astonishing to me is that anyone in the UK thought that they needed a turret for firing upward. Their own single-seat night fighters carried fixed, upward-firing guns in WW1, as did their cannon-armed night-fighter prototypes in the '30s.

Jazz Music, Baby

 

[pathology_doc]

Ah ok I thought it was to turn them into Defiants, you know, like the Skua / Roc abomination. I readily agree that night fighting was an all different matter - without scores of 109s to wipe them out of the sky like Defiants it made some sense.

Even if the thought of a Defiant-ized Mosquito or a Roc-like Beaufighter is still sickening from an aesthetic point of view.

What's astonishing to me is that anyone in the UK thought that they needed a turret for firing upward. Their own single-seat night fighters carried fixed, upward-firing guns in WW1, as did their cannon-armed night-fighter prototypes in the '30s.

Jazz Music, Baby

Yeah, but the Luftwaffe's bombers, for all their faults as strategic bombing platforms, had something almost every British four-engined night bomber lacked - a ventral gun position that could give warning of below-and-behind attackers*. Schrage Musik thus operated in an ideal tactical milieu. I remember reading somewhere that SOME British bomber crews with an H2S blister stripped the radar out and field-fitted a window and a single .50 Browning pointing to the rear (because if you can only have one machine gun, take the best) to give warning and apply some disincentive.

* Even for those heavies that did have a ventral turret, it was periscopically sighted and not ideal for keeping a lookout. It would be interesting to theorize on how well Schrage Musik would have worked had the night bombing phase been flown by American bombers with ball turrets.

 

[iverson]

Ah ok I thought it was to turn them into Defiants, you know, like the Skua / Roc abomination. I readily agree that night fighting was an all different matter - without scores of 109s to wipe them out of the sky like Defiants it made some sense.

Even if the thought of a Defiant-ized Mosquito or a Roc-like Beaufighter is still sickening from an aesthetic point of view.

What's astonishing to me is that anyone in the UK thought that they needed a turret for firing upward. Their own single-seat night fighters carried fixed, upward-firing guns in WW1, as did their cannon-armed night-fighter prototypes in the '30s.

Jazz Music, Baby

Yeah, but the Luftwaffe's bombers, for all their faults as strategic bombing platforms, had something almost every British four-engined night bomber lacked - a ventral gun position that could give warning of below-and-behind attackers*. Schrage Musik thus operated in an ideal tactical milieu. I remember reading somewhere that SOME British bomber crews with an H2S blister stripped the radar out and field-fitted a window and a single .50 Browning pointing to the rear (because if you can only have one machine gun, take the best) to give warning and apply some disincentive.

* Even for those heavies that did have a ventral turret, it was periscopically sighted and not ideal for keeping a lookout. It would be interesting to theorize on how well Schrage Musik would have worked had the night bombing phase been flown by American bombers with ball turrets.

I doubt that ventral gun positions were ever very effective at spotting aircraft approaching from below.

First off, they did exist. Hampdens had ventral gun positions very like the German ones, RAF Fortresses and Liberators came with the best such defense, the Sperry ball turret, which the RAF chose to delete even on 100 Group aircraft that carried H2S in the forward fuselage. Moreover, the gunner's field of view from the rear turrets of the other RAF bombers was undoubtedly good enough to spot any visible aircraft approaching from the rear and below. The problem was that such aircraft were generally not visible, with or without a mid-vental gun position.

The sky is always brighter than the ground. So, when seen from above, an approaching aircraft is effectively invisible, even on brightly moonlit nights. When seen from below, the opposite is the case. The primary advantage of upward firing armament is thus that the target is silhouetted against sky while the attacker remains safely hidden.

Germany abandoned black night-fighting colors for pale blue in a partial attempt to mitigate the silhouetting problem when seen from below (pale upper surfaces made little or no difference when viewed from above). Black was only retained for the undersurfaces of bombers and fighters operating in close proximity to search lights.

The main advantage of eliminating H2S (if that was ever, in fact, done on aircrew authority alone) would be to eliminate its tell-tale emissions. It was effectively an aircraft-mounted, RF searchlight advertising the bomber's position to any adversary that had one of several available homing receivers installed. Tragically, many RAF crews believed that it had a jamming effect against the German radars and kept it switched on continuously. Replacing it with a gun might thus appear to have a deterrent effect simply because it made the bomber much harder to find than it would have been otherwise.