Why the lack of high-altitude reconnaissance aircraft during WWII?

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There are some late war examples of high altitude aircraft, such as modified Spitfires, Mosquitos, and the Ju-388, recorded at altitudes around 45,000ft, but why was nothing purpose built for high altitude reconnaissance for missions above 50,000ft?

Given the tech of the day, it certainly seems like it was possible to design a high aspect wing, piston powered aircraft with a P-47 like "turbosupercharger" or even an auxiliary powered supercharger à la Grob Strato 2C.

Junkers_Ju388L-1.jpg
 
I suspect pressure cabin technology wasn't really mature enough for a more widespread application back then; e.g. the only ones to mass-produce a pressure cabin-equipped frontline bomber with the necessary remote-control facilities for armament actuation were the Americans (the B-29), and they had the luxury of a huge industrial base which was completely immune to enemy bombing attack (through distance if nothing else). Even then, it didn't get into service until 1944 and it had more than its own share of problems.


Given the ease with which a somewhat lightened (machine guns taken out) standard Spitfire IX apparently managed to stay with the -86 once it got up there, I suspect a high-blown F.VII would have been quite adequate if large numbers of them had required dealing with. Anything faster or higher-flying might have required the early introduction of a high-blown and pressurised Griffon Spitfire, perhaps something like an armed version of the PR.XIX.


Given how many successful Spitfire variants did start out as lash-ups, this seems quite reasonable to postulate.
 
The F-13 (B-29) was a high altitude reconnaissance airplane. -SP
 
the Allies had no need and the Germans possibly couldn't afford
Click to expand...

Perhaps this explains it more than for lack of technology, though I wonder if the technology existed even early-mid war and would have been achievable had it been a priority. The B-29 served the role, but it was never designed specifically for that purpose and, AFAIK, couldn't reach the altitude of modified high-altitude Ju-86s and the like. The Wasp Major powered B-50 may have been able to be modified to reach 50,000ft, but by then jets were in vogue and the Canberra came shortly after.

45,000ft was certainly achievable by the end of the war, but was 50,000ft? Even more interesting could be speculating how early in the war such an aircraft could have existed if there had been an invested effort for the sake of gaining intelligence. Or, given modern knowledge on aerodynamics and using computational fluid dynamics, could a plausible spyplane be designed if limited to the technology of WWII?



The Grob Strato 2C is probably the best modern example of a high-altitude piston-powered aircraft, but it weighs the same as a Ju-86 with engines that produce less than half the horsepower (save for its internal turbine "supercharger") and the Strato could reach 60,000ft+.

1774484.jpg
 
oops, accidentally triple posted there trying to edit my previous post.
 
That Germany not had a high-altitude reconnaissance aircraft
was thanks to the stupidly of "Reichsluftfahrtministerium" (RLM) who not see need for that kind of Aircraft.
they even canceled the a high-altitude reconnaissance aircraft DFS 228 in 1941 in believe they won already the war.
and much to late in 1942 the "Technische Amt" of Luftwaffe start to demand for high-altitude aircraft, They demand were for high-altitude fighters !
After Stalingrad RLM had suddenly the need for a high-altitude reconnaissance aircraft
So the DFS restart work on high-altitude DFS 228 in begin 1943, again much to late in war...
in october 1944 they made first drop test of DFS 228 from a Do 217.
production of DFS 228 start march 1945 and was terminated on may 1945 with end of world war II.
 
I don't think, that the DFS 228 would the kind of high-altitude aircraft, that was needed. It had to be carried
piggy-back (and at normal ceiling) and although it is generally credited with a range of about 1000 km, for staying
at maximum ceiling, this would have been considerably shorter.
If the developments of the Ju EF 61, or the Henschel Hs 128/130 would have proceeded with uninterrupted, maybe
a service capable high-altitude recce aircraft/bomber could have been ready after the "standard time" for the introduction
of new technologies, which for example by Ralf Schabel (author of "Die Illusion derWunderwaffen") is given as something
around 5 years ! So, under best circumstances, such aircraft, in mature form, could have flown around 1943. As the industrial
capacities of Gremany were needed for other purposes and the high-altitude aircraft never had highest priorities, this date
was just delayed a little bit, maybe to ... 1947 ?
 
45,000ft was certainly achievable by the end of the war, but was 50,000ft?


I recall reading somewhere that Spitfire XIX's were used in interception exercises with early postwar jets and that some of them - given leave to take their time - worked up to quite phenomenal altitudes (49,000ft is quoted) before starting their approach runs into the exercise areas. Sure, that sort of flight plan might not have been operationally realistic in a shooting war, but it does demonstrate the ability of a wartime design to at least approach the magic 50K mark.
 
The B-29 served the role, but it was never designed specifically for that purpose - The F-13 version of the B-29 certainly was. -SP
 
Altitudes above 50k ft were already achieved in the second half of the 1930s by the Bristol Type 138 and the Caproni Ca.161.

Martin
 
In the case of the F-13, a B-29 was modified for the role, not designed for it. It served the same purpose which leads us back to the allies never needing it, but I'm thinking more of a U-2 type endeavor to develop a dedicated high-altitude reconnaissance aircraft that could fly over enemy territory with impunity. There were aircraft achieving heights 50,000ft+ like the Caproni, but they wouldn't have had the endurance, range, or payload for proper camera equipment to operate as useful spyplanes.
 
The Henschel Hs 130 was a design aimed at 15,100m (49.500 ft) and one of the Hs 130A's is said to
have actually reached 15,500 m (50,850 ft), late during 1943. But those still were test aircraft, although
built in small numbers. For high-altitude flight new ground had to be broken on several fields, propulsion,
aerodynamics and structures, as a service capable aircraft had to fit other criteria, than a record aircraft.
With hindsight it seems to me, that this task had been underestimated my the German companies, coupled
with too low interest by the officials, not feeling the need, as Michel already pointed out.
 
ISTR Junkers Ju 86R-1 and Dornier Do 217P-0 flew at 50,000 ft+. Only a handful of either type was built.
 
With only online sources at hand now, I've found, that the Ju 86R-1 was capable of at least 47,500 ft, whereas
the Do 217P, theoretically able to reach 53,000 ft, was a similar case as the Hs 130. Both were using the troublesome
"HZ-Anlage" with an additional engine in the fuselage driving a central supercharger.
(Interesting side note: I found mentioned a "Ju 186", a proposed four engined development of the Ju 86)

While having a quick look at the service history, it seems clear, that what was needed was an aircraft with a service ceiling
of at least 50,000 ft, which surely would have been able to reached much higher peak altitudes for a short while. What
was available with the Ju 86P, was an aircraft, that flew its missions at around 42,000 ft and climbed higher only if forced
to.

EDÍT: I've moved this topic to the Military section, as we aren't actually discussing alternative scenarios, but the the possibilities
and reasons for high altitude flying during WW II.
 
pathology_doc said:
I recall reading somewhere that Spitfire XIX's were used in interception exercises with early postwar jets and that some of them - given leave to take their time - worked up to quite phenomenal altitudes (49,000ft is quoted) before starting their approach runs into the exercise areas. Sure, that sort of flight plan might not have been operationally realistic in a shooting war, but it does demonstrate the ability of a wartime design to at least approach the magic 50K mark.
Click to expand...
some Air International articles from the 1990s refer to an exercise in the late '40s and it is the poor state of British air defences after WW2 that's blamed . For a couple of Spitfires were not even spotted by Radar , let alone Meteors hunting them .
 
Could camera and film technology have had a hand in it? If the resolution, for whatever reason - film grain, stabilisation, lens quality (even Leitz/Zeiss...), heating - wasn't good enough to merit higher altitudes, why do it? If you can put a camera at 50000ft and it can't resolve the difference between the Tirpitz and a tanker is there any point in flying higher?

Chris
 
CJGibson said:
Could camera and film technology have had a hand in it? If the resolution, for whatever reason - film grain, stabilisation, lens quality (even Leitz/Zeiss...), heating - wasn't good enough to merit higher altitudes, why do it? If you can put a camera at 50000ft and it can't resolve the difference between the Tirpitz and a tanker is there any point in flying higher?

Chris
Click to expand...
Possibly. On the other hand, about 40 Ju 86s were converted to Ju 86Ps and flew regularly until 1943. Use of the Ju 86Ps came to an end when several Ps were shot down by converted Spitfires. Development of 50,000ft+ Ju 86R and Do 217P might have been just enough to stay out of reach of high-flying interceptors - as it was, some Arado Ar 234s were later used as reconnaissance aircraft, relying more on speed than on flying high to stay out of harm's way.
 
I may be wrong, but just thinking geometrically, the difference between a photo taken from 15 km height to one from
12 km should just be, that objetcs are shown 20% smaller, than from the lower altitude. Don't think, that this
would render photos useless. At a height of 11 km, temperatures are around -55 °C and stay there, until you
reach around 20 km. The photographic systems, that were found to be sufficient for the Ju 86P/R variants so
could have been used for higher flying a/c, too, I think.
 
Since we're talking about reconnaissance and Spitfires, you folks might find this documentary short posted today interesting.

http://www.youtube.com/watch?v=ie3SrjLlcUY&feature=youtu.be


If missions like this were successful, then there was little need for high altitude reconnaissance except for gathering information in the thickest of defended airspace. The Germans seem to have been working on some stuff, but they never really came to fruition en masse by the end of the war.

I started ask myself "why no high-altitude aircraft" a few weeks back. I have access to CFD simulation software and am a 3D modeler by trade and am considering creating a few fictional prototypes limited to the tech of the era.
 

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