Questions about B-29 operational range, VVS, VVS intercept capability if Operation Unthinkable happen.

[Dimlee]

I look at the last posts and think the most addictive topic is the "off-" one. Blame me for starting that!
Anyway...

Back to the Unthinkable.

If faced with the bomber offensive, the Soviets must do something urgently. Emergency fighter program?
BI rocket fighter development was not very successful in real life and was already outdated when it was completed in 1945. Light armament, transonic effects not fully researched, short life of the equipment due to corrosion...
But probably the resumption of the BI program is the only solution in the summer 1945?
(Not for the night fighting, of course).

 

[bf109xxl]

If faced with the bomber offensive, the Soviets must do something urgently. Emergency fighter program?
BI rocket fighter development was not very successful in real life and was already outdated when it was completed in 1945. Light armament, transonic effects not fully researched, short life of the equipment due to corrosion...
But probably the resumption of the BI program is the only solution in the summer 1945?
(Not for the night fighting, of course).

It was a good way for the Soviets to kill their most experienced pilots. The BI-1 cannot be compared even with the Me 163. I'm not sure it was capable to shoot down anyone directly over its own airfield. It is purely an experimental airplane, more dangerous to the Soviets themselves than to anyone.

 

[Thumpalumpacus]

I look at the last posts and think the most addictive topic is the "off-" one. Blame me for starting that!
Anyway...
View attachment 803745


Back to the Unthinkable.

If faced with the bomber offensive, the Soviets must do something urgently. Emergency fighter program?
BI rocket fighter development was not very successful in real life and was already outdated when it was completed in 1945. Light armament, transonic effects not fully researched, short life of the equipment due to corrosion...
But probably the resumption of the BI program is the only solution in the summer 1945?
(Not for the night fighting, of course).

Wasn't the 85mm a pretty good AAA piece? Could they make a dent?

 

[bf109xxl]

Wasn't the 85mm a pretty good AAA piece? Could they make a dent?

Sure. Up to 10000 m, however the command device (PUAZO) could track targets with speed less then 540 kph. Large caliber AAA was developed much later - 100mm KS-19 in 1948, 130mm KS-30 in 1952.

 

[GrauGeist]

I look at the last posts and think the most addictive topic is the "off-" one. Blame me for starting that!
Anyway...
View attachment 803745


Back to the Unthinkable.

If faced with the bomber offensive, the Soviets must do something urgently. Emergency fighter program?
BI rocket fighter development was not very successful in real life and was already outdated when it was completed in 1945. Light armament, transonic effects not fully researched, short life of the equipment due to corrosion...
But probably the resumption of the BI program is the only solution in the summer 1945?
(Not for the night fighting, of course).

The BI would be more trouble than it's worth, to be honest.

On the otherhand, the VVS did have lend-lease P-47Ds. Those may have been useful.

 

[Reluctant Poster]

No, it's not. If we consider the effect of altitude over the target (i.e. enemy impact), we should not distort it by losses due to other factors. The essence of statistical analysis is to determine the role of each factor separately so that the resulting data can be used for forecasting/planning.
The flight altitude profile did not vary much except for a segment near the target.

For planning of operations it is absolutely irrelevant what the crew in the dinghy off the coast of Japan hope for, or whether they hope at all.

That makes no sense what so ever. The effect of altitude over target on losses was not solely due to enemy action. It would have been foolish off the USAAF not to take all factors into consideration. And that's exactly what they did in deciding to reduce bombing altitude.

 

[bf109xxl]

That makes no sense what so ever.

That surely make sense - even if it was not done at that time.

The effect of altitude over target on losses was not solely due to enemy action.

If the altitude during the whole flight was 30k, there is no question that this factor was of a greater importance. However, if the bombers climbed to 30k only over the target and then descended again on the way back, then it is unlikely that this greatly increased the malfunction probability. What was the altitude profile in the raids?

It would have been foolish off the USAAF not to take all factors into consideration. And that's exactly what they did in deciding to reduce bombing altitude.

The difference between 26k and 30k is not big enough - the Japanese AAA was still not effective. There was a sharp increase in damage from AA fire when the altitude was reduced to 18k. But even this increase was not fatal. Nevertheless, the increase was observed, and seems that the reliability factor was not properly analyzed - the number of observation was not taken into account to compare the malfunction rates. In general, the statistical theory of reliability was developed after the war, as far as I know.

 

[GrauGeist]

Shortly after LeMay took over XXI BC in January 1945, there were staff meetings after every bombing mission to discuss operational issues and from that information gathered, adjusted the tactical doctrine.
This would include bombing accuracy, aircraft and crew performance and cause of losses (including operational failures).

So no, hard statistics were not solely compiled post-war.

 

[bf109xxl]

Shortly after LeMay took over XXI BC in January 1945, there were staff meetings after every bombing mission to discuss operational issues and from that information gathered, adjusted the tactical doctrine.
This would include bombing accuracy, aircraft and crew performance and cause of losses (including operational failures).

So no, hard statistics were not solely compiled post-war.

There is no doubt that all the data was analyzed at different levels of command. There is no doubt that all factors were taken into account. But correct consideration of some factors was quite difficult. For example, if the statistics of engine failures is available, it is possible to find a value characterizing the probability of engine failure per unit of time depending on its life (engine hours), it can also depend on the flight altitude. Then it is necessary to study the statistics of engines on all airplanes in the raid - most likely, the distribution of the resource will be approximately the same in each raid, then you can calculate the probability of failure of aircraft in one raid, thus, to estimate the number of losses due to technical reasons. It will depend on the number of airplanes in the raid. But in this particular case the difference is not so crucial to bother with any calculations. Despite a slight increase in losses from anti-aircraft fire (compared to losses during bombing from 18k altitude), the level of losses remained acceptable.
But I would still appreciate information on the flight altitude profile in these raids.

 

[Reluctant Poster]

If the altitude during the whole flight was 30k, there is no question that this factor was of a greater importance. However, if the bombers climbed to 30k only over the target and then descended again on the way back, then it is unlikely that this greatly increased the malfunction probability. What was the altitude profile in the raids?

Of course the whole flight wasn't done at 30,000 feet. The fact that you would even ask that question shows your lack of knowledge in this subject. I notice that your posts in general are long on conjecture and short on facts. I think you're trolling and won't bother responding to your posts

 

[bf109xxl]

Of course the whole flight wasn't done at 30,000 feet. The fact that you would even ask that question shows your lack of knowledge in this subject.

I've made no secret of it. You could provide information, but you decided to use personal attacks instead.

I notice that your posts in general are long on conjecture and short on facts.

That's simply not true.

I think your trolling and won't bother responding to your posts

I would be very grateful if you would keep your word.

 

[GrauGeist]

It would be nice to be able to get back to the original topic...

 

[bf109xxl]

It would be nice to be able to get back to the original topic...

Sometimes deviations of the discussion can be useful in addressing the original topic. At what altitude would B-29s fly over the USSR? Taking into account that Soviet air defense aviation outnumbers the Japanese by far, altitude will be the only defense - escort is not expected due to insufficient range. This is not a flight over the ocean, a return at the altitude of 8k is hardly possible, as well as a long flight to the target at altitudes 10 to 20k.
What exactly were the technical reasons mainly responsible for the losses in the raids on Japan? Lack of fuel? Engine failure/fire? How would flight conditions over the USSR affect losses due to technical reasons? These are not rhetorical questions and I would appreciate the information.
I could give a brief overview of the development of high-altitude fighters in the USSR, but I'm not sure it would be of interest to anyone here.

 

[Shortround6]

I could give a brief overview of the development of high-altitude fighters in the USSR, but I'm not sure it would be of interest to anyone here.

It may be of interest.
What is relevant is what did they have in squadron service and when.
The Mig-3 was a high altitude fighter when first deployed. How many were left or how it would have even dealt with even B-17s is subject to question.
The Soviets had number of high altitude fighters in development.
How many months to get them into production?

 

[bf109xxl]

The Mig-3 was a high altitude fighter when first deployed. How many were left or how it would have even dealt with even B-17s is subject to question.

Just a short remark: initially MiG-3 was developed as a high-speed front-line fighter. It was assumed later as a high altitude fighter due to a better engine performance over 6km, but it was rather a bonus as a real demand. The service ceiling of the MiG-3 did not exceed 11500 m.

 

[Shortround6]

And the early P-40 had a service ceiling of 9980 meters and we know how that worked out

 

[Thumpalumpacus]

What exactly were the technical reasons mainly responsible for the losses in the raids on Japan? Lack of fuel? Engine failure/fire?

R-3350s were prone to overheating which resulted in engine shutdowns or fires. That was one reason Iwo Jima was assaulted -- not to provide escorts, though that was a happy side-effect -- but because when a B-29 goes down in the ocean ten guys are almost surely dead unless they get lucky and an American sub pulls up.

So lowering altitudes relieved stress on the engines, reducing the likelihood of engine fires. This is exactly why R Reluctant Poster mentioned operational losses and how the higher command took those into consideration -- not because of statistics, but because these were guys who'd been flying big bombers for years and understood the issues.

Over western Russia, without jet-streams raising issues, flying at 25-28,000 ft could well work. I'd think the range of ops should still be reduced to maybe 700-800 miles, because prevailing winds will turn damaged A/C into losses more. But if my bomber can do 350 mph at 25,000 ft and your fighters are huffing for breath and it's only up to your AAA, that's odds I'd like.

Blanket the airfields, then concentrate on marshaling yards, put medium bombers against bridges and airfields both, and use fighters to shoot up rolling stock and airfields on the way home. It's not like the Western Allies were babes in the woods.

 

[bf109xxl]

Since the end of 1943, three design bureaus (Mikoyan/Gurevich, Yakovlev, Lavochkin) were engaged in the development of a high-altitude fighter. But despite almost daily (!) government supervision, progress was extremely poor, primarily due to the lack of suitable engines. Yakovlev used the M-105PD (a modification of M-105P), M-106PV, and M-105PV (a modification of the M-105PF) engines with a two-stage SC of Dollezhal's design. The Yak-7 with the M-105PD, the Yak-9 with the M-105PD and M-106PV and the Yak-3 with the M-105PD and M-105PV engines were tested (designation in all cases was Yak-...PD). The main problem was engine overheating, requiring intermediate leveling off during service ceiling climb. In practice, the service ceiling of the Yak-9PD with M-105PD of early production was lower than that of the Spitfire VB (11100m vs. 11500m, for comparison: in the same conditions the P-39 reached 9000m, the Yak-1 9500m, and the MiG-3 10800m during the attempt to intercept a Ju 86R on August 22, 1943 over Moscow). The M-105PD was further modified by changing the SC gear ratios, but the problem of overheating remained. The M-106PV engine was equipped with an air cooling system after the SC using a water-alcohol mixture, the results were much better - the airplane could climb up to the service ceiling of 13500 m without intermediate leveling off. A speed of 620 kph was attained at the altitude of 10500 m. A total of 35 Yak-9PDs were built, 30 of them were equipped with the M-106PV engine.
The best performance was demonstrated by the Yak-3PD with the M-105PV engine: service ceiling 13300 m, 710 kph at 11000 m. Up to the altitude of 12500m the aircraft had good controllability and sufficient power to perform all the necessary combat maneuvers.
The armament was rather insufficient - one 23-mm gun, the aircraft was extremely lightened by reducing the fuel capacity, and the range was too short even for an interceptor. In spite of the fact that it was quite ready for serial production, theoretically able to fight both bombers and escorts, I have certain doubts about its real value. It was designed more for intercepting single high-altitude scouts than for attacking a formation of bombers.
Although the installation of an intercooler seemed to be an effective solution of the M-105 overheating problem even to that time, for some reason the Soviets did not make a try - it's a mystery to me. Nevertheless, the two-stage SC was brought to the required degree of reliability, production of both the M-106PV and M-105PV could well be quickly deployed (already in late 1945) if necessary.
Lavochkin tried to install a turbocharger on his fighters, but without much success - we can safely assume that the result was zero.
Mikoyan and Gurevich continued to improve the MiG-3 consistently - despite all the differences, their high-altitude fighters were structurally a further development of the MiG-3, while their engines were a development of the AM-35. According to some evidence Mikulin could afford a kind of "sabotage" - if he did not like the task, he invented various reasons for delaying the work. In the USSR such behavior could have dire consequences, but apparently Mikulin's merits with the AM-38 and AM-42 were valued so highly that the Soviet leadership forgave him his oddities. As a result, Mikoyan and Gurevich never got a fully operational high-altitude supercharged engine with desired performance from Mikulin. The solution was sought in the use of (initially) a low-altitude engine (AM-42B) with an AMTK-1 turbocharger, satisfactory functioning of which Mikulin did achieve. The performance of the I-225 was high enough to consider it a real threat to Allied bombers. Nevertheless, an engine with acceptable performance (AM-39FN2 aka AM-40) did not appear until the end of 1945, and its serial production began only in late 1946. It is difficult to say whether it was possible to accelerate its finalization, but most likely yes, a mass series could be expected in early 1946. In reality, from the middle of 1945 Mikoyan and Gurevich already focused on the development of the I-250 (another absolutely futile idea).
Thus, in early 1946, the Soviets could have fighters capable of intercepting the B-29 - I estimate the effectiveness as rather low, but B-29 losses could be much higher than in the raids on Japan if bombers were detected in time taking into account the potential numbers of Soviet fighters. The Soviets used radars, but the most industrial centers deep in the European part of the USSR had either completely inadequate radar detection or even not at all.
No new technology was required to manufacture these fighters, so they could be produced in fairly large quantities if necessary.
The most intriguing question is where the Soviets will get the high-octane gasoline for the manufactured high-altitude fighters.

 

[bf109xxl]

R-3350s were prone to overheating which resulted in engine shutdowns or fires. That was one reason Iwo Jima was assaulted -- not to provide escorts, though that was a happy side-effect -- but because when a B-29 goes down in the ocean ten guys are almost surely dead unless they get lucky and an American sub pulls up.

I would like to see the frequency distribution of the various reasons for technical failures.

So lowering altitudes relieved stress on the engines, reducing the likelihood of engine fires.

Or reduces the chance of overconsumption of fuel. And airplanes with engines with fewer defects could also be delivered. Or just new engines for replacement.

because these were guys who'd been flying big bombers for years and understood the issues.

The B-29 was a fundamentally new machine, there was not yet much experience with such aircraft. All the "big bombers" became not big enough.

Over western Russia, without jet-streams raising issues, flying at 25-28,000 ft could well work

I do not mean the altitude over the target. And it is much higher than typical altitude on the route in the raids on Japan.

I'd think the range of ops should still be reduced to maybe 700-800 miles

You don't need the B-29 for this range. I emphasized that the greatest effect could be achieved by raids on poorly defended compact industrial centers deep in Russia. That's 1,800-2,000 miles if you take off in Norway or the Middle East. I doubt a safe airfield could be found any closer.

But if my bomber can do 350 mph at 25,000 ft and your fighters are huffing for breath and it's only up to your AAA, that's odds I'd like.

Soviet fighters in 1945 weren't huffing for breath at 25k, they started huffing somewhere around 28k, if not higher. That's why I asked at what altitudes flights over the USSR are supposed to be carried out. In any case, this is in no way comparable to the raids on Japan from the Marianas where only a relatively small part of the route assumed a high-altitude (over 20k) flight.

Blanket the airfields, then concentrate on marshaling yards, put medium bombers against bridges and airfields both, and use fighters to shoot up rolling stock and airfields on the way home. It's not like the Western Allies were babes in the woods.

The problem is that by the time of B-29 deployment in Europe, it is too late to blanket the airfields - the bombers from the 8th and 15th AF will be doing that. B-29s are needed for strategic destruction of industrial potential of the USSR, their use for tactical tasks is little justified, in my humble opinion.

 

[GrauGeist]

For shorter range bombing missions, the B-29 could carry 20,000 pounds of bombs.

"Shorter" range for a B-29 is roughly a long range mission for a B-17 or B-24, which carried about 4 to 5 thousand pounds.

So a single superfortress is hefting the equivellant of five B-17s to a target and I'm willing to bet that targets within Soviet occupied areas of Eastern Europe would get the full treatment.