1942-45 USAAF/RAF western front high altitude interceptors.

[BarnOwlLover]

This is a "big" what if, in that I'm hoping that it'll encompass aircraft that made it into service, aircraft that were evaluated, aircraft not used in the role but might have worked, prototypes, and paper projects. And I'll be looking at "light" (single engine) and "heavy" (twin engine) aircraft.

These are actual and proposed counters to the prospect of Luftwaffe high altitude bombers and the actually faced element of Ju-86 high alt. recon aircraft.

Among the aircraft (and it's not an all inclusive list, so you're allowed to add your own contributions) that I'll be including are:

Light:

Spitfire VII/HF VIII, lightweight Spitfire HF IX, Miles M23A, P-51B/C. P-51D/K, P-51H/L, XP-51F/G, P-47M (though light might be stretching it), XP-72 (see previous, and an evolution of the P-47 using P&W R-4360), Hawker Tempest with either two stage Griffon/Sabre/Centaurus, Hawker Fury with two stage Sabre/Centaurus, HF version of the Spitfire XIV/20 series, others

Heavy:

Westland Welkin (actual or improved), Mosquito F/NF XV, P-82B/C/D Twin Mustang, P-38J/L/K, P-38 with two stage Merlins, Vickers 432, others.

What would've/might have worked, what would you improve, what would you do?

 

[wuzak]

The obvious one is the Spitfire XIV. Or the Spiteful XIV and XVI.

Or a jet like the P-80.

You might have to suggest aircraft these high altitude interceptors were going to intercept, since Ju 86 flights stopped before most of the suggested aircraft were available.

 

[BarnOwlLover]

The Ju-86 was the influence behind this, and it did seem that the British especially didn't put it past the Luftwaffe to mount further recon/nuisance bombing raids, using aircraft that could fly at similar altitudes but with better performance.

Oddly, the Sept. 1942 lw Spitfire IX interception over England (that resulted only in light damage to the Ju-86) and the destruction of one by a lw HF Spitfire V at 49,000 feet over Egypt the previous month lead to the LW scrapping any further major high alt. raids over Allied occupied territory.

Basically anything 25,000-30,000 feet or above will suffice for discussion.

 

[PAT303]

If it wasn't for a jammed cannon both would have been shot down.

 

[BarnOwlLover]

One thing that should be noted is that the XP-51F was being flown at altitudes in testing of over 45,000 ft, and the XP-51G attained 46,000+ ft. The F had standard V-1650-3/7 Merlins, and the G had the RM 14SM (Merlin 100 prototype), which were general purpose/mid alt. engines (though the -3 was biased for higher altitude work, which suited the F as it was designed as an interceptor). I think that the -3 was based on the Merlin 61/63, and the -7 was based on the Merlin 66. The Merlin 100 and 130 series/RM 14SM were improved Merlin 66s, while the RM 16SM/Merlin 110 series were improved 61s/63s/70 series.

But back to the XP-51F/G, the limiting factor in terms of ceiling was that they didn't have pressurized cockpits. And outside of the Welkin, I don't know of any fighters that I listed that had them (Miles M23A was supposed to have one, but remained a paper exercise, and maybe the Spitfire VII had one).

 

[yulzari]

A notable height issue was heating. Both crew and guns. The first tranche of Flying Fortresses in RAF service found the 0,5" Brownings freezing even the limited amount of lubrication seizing up the guns. Not a new matter. In the Tibetan winter the Lee Medford's and Maxims were fond to freeze the bolts solid in the coldest winter weather even with the guns cleaned dry of oil. Mind you the Gurkhas and Sikh Pioneers fought their last action before Lhasa at a pass at 19,000 feet.

 

[MikeMeech]

One thing that should be noted is that the XP-51F was being flown at altitudes in testing of over 45,000 ft, and the XP-51G attained 46,000+ ft. The F had standard V-1650-3/7 Merlins, and the G had the RM 14SM (Merlin 100 prototype), which were general purpose/mid alt. engines (though the -3 was biased for higher altitude work, which suited the F as it was designed as an interceptor). I think that the -3 was based on the Merlin 61/63, and the -7 was based on the Merlin 66. The Merlin 100 and 130 series/RM 14SM were improved Merlin 66s, while the RM 16SM/Merlin 110 series were improved 61s/63s/70 series.

But back to the XP-51F/G, the limiting factor in terms of ceiling was that they didn't have pressurized cockpits. And outside of the Welkin, I don't know of any fighters that I listed that had them (Miles M23A was supposed to have one, but remained a paper exercise, and maybe the Spitfire VII had one).

Hi
Of course the Spitfire VII had a pressure cabin, its predecessor the Mk. VI had one as well, diagram from Mogan & Shacklady below:

Supermarine and the RAE had been working on the pressure cabin during 1940-41, after all it became a needed requirement lesson learned by Fighter Command during the BoB as fighting was getting to higher altitudes 25,000 to 30,000 ft. was common and aircraft were operating above those altitudes. The Mk. VI emergency HA fighter had a 40,000 ft. Service ceiling, the Mk. VII was 43,000 ft. The Mosquito HA night fighter projects also had pressure cabins, but there was not really a demand for these.
The US Curtiss XP-62 was fitted with a pressure cabin but the prototype did not fly until 21 July 1943 (Service ceiling 35,700 ft), but the Spitfire VII had flown in April 1942 and was in service as had the Spitfire VI before both with pressure cabins and higher service ceilings.

Mike

 

[wuzak]

One thing that should be noted is that the XP-51F was being flown at altitudes in testing of over 45,000 ft, and the XP-51G attained 46,000+ ft.

The Spitfire XIV had a service ceiling of 43,000ft.

 

[Thumpalumpacus]

If it's an interceptor, perhaps defining time-to-climb would help. If we're only intercepting Ju-86, we might have more time to get to altitude. Time period would also have an effect. What's the radar like? Which planes are being intercepted?

That will influence which planes are chosen for the mission.

 

[Tom Graham]

This is a "big" what if, in that I'm hoping that it'll encompass aircraft that made it into service, aircraft that were evaluated, aircraft not used in the role but might have worked, prototypes, and paper projects. And I'll be looking at "light" (single engine) and "heavy" (twin engine) aircraft.

These are actual and proposed counters to the prospect of Luftwaffe high altitude bombers and the actually faced element of Ju-86 high alt. recon aircraft.

Among the aircraft (and it's not an all inclusive list, so you're allowed to add your own contributions) that I'll be including are:

Light:

Spitfire VII/HF VIII, lightweight Spitfire HF IX, Miles M23A, P-51B/C. P-51D/K, P-51H/L, XP-51F/G, P-47M (though light might be stretching it), XP-72 (see previous, and an evolution of the P-47 using P&W R-4360), Hawker Tempest with either two stage Griffon/Sabre/Centaurus, Hawker Fury with two stage Sabre/Centaurus, HF version of the Spitfire XIV/20 series, others

Heavy:

Westland Welkin (actual or improved), Mosquito F/NF XV, P-82B/C/D Twin Mustang, P-38J/L/K, P-38 with two stage Merlins, Vickers 432, others.

What would've/might have worked, what would you improve, what would you do?

This is a "big" what if, in that I'm hoping that it'll encompass aircraft that made it into service, aircraft that were evaluated, aircraft not used in the role but might have worked, prototypes, and paper projects. And I'll be looking at "light" (single engine) and "heavy" (twin engine) aircraft.

These are actual and proposed counters to the prospect of Luftwaffe high altitude bombers and the actually faced element of Ju-86 high alt. recon aircraft.

Among the aircraft (and it's not an all inclusive list, so you're allowed to add your own contributions) that I'll be including are:

Light:

Spitfire VII/HF VIII, lightweight Spitfire HF IX, Miles M23A, P-51B/C. P-51D/K, P-51H/L, XP-51F/G, P-47M (though light might be stretching it), XP-72 (see previous, and an evolution of the P-47 using P&W R-4360), Hawker Tempest with either two stage Griffon/Sabre/Centaurus, Hawker Fury with two stage Sabre/Centaurus, HF version of the Spitfire XIV/20 series, others

Heavy:

Westland Welkin (actual or improved), Mosquito F/NF XV, P-82B/C/D Twin Mustang, P-38J/L/K, P-38 with two stage Merlins, Vickers 432, others.

What would've/might have worked, what would you improve, what would you do?

How about the DH Vampire?

InMay 1944 it was decided to produce the aircraft as an interceptor for the RoyalAir Force(RAF).In 1946 the Vampire entered operational service with the RAF, only months after the war had ended.

On23 March 1948, John Cunningham, flying a modified Mk I with extended wing tips and powered by a de Havilland Ghost engine, set a new world altitude record of 59,446 ft (18,119 m).

It's service ceiling, in standard form, seems to have been 42,800 ft(13,045 m)

It gets a mention in this article. B-36: Bomber at the Crossroads

 

[wuzak]

If the Vampire is pushed forward, does the P80 program suffer?

 

[ThomasP]

Probably. Although it is hard to say what would or could have been done differently.

 

[MikeMeech]

Hi
The RAF appears to have had no need of any fantasy high flying interceptors they already had them in the real time line and they worked. As I mentioned the requirement for them was a result of the BoB, Dowding's Despatch on this subject (from 'Air Power Review' Summer 2015, the whole journal should be available on line if interested) extract:

With the jets coming into service the Meteor I/III and Vampire F.1 could get to around 40,000 ft, the Arado 234B-2 service ceiling was 32,810 ft, so all could reach it although only the Meteor III and Vampire F.1 were faster. The high flying B-29 with a service ceiling of about 32,000 ft was well in the parameters of ordinary RAF fighters (even the Tempest V had a service ceiling of 36,000 ft and the Spitfire XIVe was 44,500 ft) let alone the specialist high flyers, and that was the most advanced heavy bomber of WW2.

Mike

 

[PAT303]

The obvious choice was the MkXIV, maybe talk to Rolls about making a Merlin 46 equivalent Griffin or a three speed Griffin, ditch all the protection and survival gear other than the parachute, anything not needed, boost the engines, we are not worried about engine life here, delete the cannon stubs, tape over the ejection shutes, fit the Seafire MkIII streamlined blisters, individual ejector stubs and paint and polish them to a high finish, last of all park them in hangers or shelters to keep the weather off them. That would be the way I would do it.

 

[RCAFson]

Pressure suits are a cheap alternative to a pressurised cockpit.

 

[BarnOwlLover]

About any German piston engine bomber that was used in numbers could be intercepted by any RAF or USAAF fighter that had like a 30,000+ foot service ceiling. But the RAF (also based on BoB experiences, as well as worries that the Ju-86 caused) wanted high altitude fighters. The resulted in stuff like the Welkin and the Spitfire VI/VIII and such.

And the info posted above does hint at what the RAF were looking at. And the development of the P-51B/D Mustang was driven by overall and especially high altitude performance due to USAAF favoring high altitude bombing over Europe. Granted, the V-1650-7 was rated for somewhat lower altitudes partly because most German fighters couldn't operate well above 25,000 feet.

But there was the Ta-152, which could fly at over 47,000 feet. And remember that in testing the XP-51F/G topped out at just above 46,000 ft. Not because of lack of engine power, but lack of pilot oxygen. And as also suggested above, it seems that you do need a pressure cabin much above 40,000.

I don't know if pressure suits were/are more practical than a pressurized cockpit.

 

[PAT303]

There was fighting in the BoB above 30,000 feet is standard MkII Spits and 109 Emils so you can see why the British were taking the development of dedicated high altitude aircraft seriously, lucky they did because it gave the Allies the 60 series Merlin.

 

[MikeMeech]

Hi
The main US contenders for high altitude interceptors (or stated to be)are the Curtiss XP-62 and Vultee XP-54 for USAAF and Curtiss XF14C-2 for the USN, all were or were going to be fitted with pressurized cockpits all were cancelled. The XP-47E was fitted with a pressurized cockpit but it has been quoted to being "... difficult to install and perfect, cockpit sealing being a big problem."
I not sure why the US had a problem with this undertaking as the UK appears to have had much better success and earlier in the war. It may be that the British took it rather more seriously as it was closer to enemy air power and the whole of the country was in range of enemy bombers. The continental USA in contrast was well away from that danger so maybe did not see the problem as urgent (The USAAF in the UK and MTO could rely on the RAF to supply high altitude interceptors to deal with the problem).
Indeed if the whole of the USA was in range of enemy day/night bombers the priorities of war production and expenditure there would have changed immensely.

Mike

 

[BarnOwlLover]

Or it could also be that by the time the USAAF got involved in affairs over Europe, one, Germany basically stopped the Ju-86 overflights and (albeit slowly) started to turn their attention to fighter defense. And two, the RAF and USAAF didn't field bombers or recon aircraft over the ETO with pressurized cockpits. The B-29 only was used in the Pacific, and only a handful of Mosquitos were flown with pressure cabins over Europe.

The B-29 being shown in England did reportedly cause (or at least contribute) to the scare that led the Luftwaffe to develop aircraft like the BV-155 and the Ta-152. However, the BV-155 never flew in combat and the Ta-152 did see limited combat use, but mostly as a normal fighter--where it basically seemed to do no worse, nor no better--than the Fw-190D.

Not to mention that the USAAF shifted from developing interceptors to escort fighters in late 1943. Which meant no XP-51F/G, no XP-72, and other promising projects also got the axe.

 

[EwenS]

..the RAF and USAAF didn't field bombers or recon aircraft over the ETO with pressurized cockpits. The B-29 only was used in the Pacific, and only a handful of Mosquitos were flown with pressure cabins over Europe.

Mosquito 432 PR.XVI built for worldwide service, 402 B.XVI for service with British based squadrons. All with pressure cabins.

Hardly a handful.