TA-152 vs B-29

[Reluctant Poster]

Actually my favorite excerpt from AWPD-1 is:

Gunner over claiming was a multinational affair

 

[FLYBOYJ]

I agree that the gunners did well, but keeping the sight on target is only part of the equation. The question I have is how well the computers did at translating the gunners input into putting bullets on target. There a lot of variables to be taken into account with not a lot of processing power to do the complex math. How quickly and precisely do the turret mechanisms respond? Remote turrets introduce the problem of parallax requiring accurate determination of target range. As I posted recently variability seems to have been a problem for the GE system.

Along with my uncle, I met several other people who flew in B-29s during WW2. A middle school shop teacher (who was also a radio operator like my uncle and flew during Korea) had similar comments about the fire control system as it was almost impossible to optically track the MiG-15 during the Korean War. Our family insurance agent (when I was a kid) was a B-29 navigator, flew in the PTO and spoke very highly of the system (as well as the rest of the B-29) but did comment that once jets appeared the system was obsolete. I guess during training missions Uncle Bill got to play in a turret and he said that piston engine fighters could be tracked, unless they dove at "high speeds."

 

[Thumpalumpacus]

Assuming there is the capacity to make 3 times the number of bombs and the shipping space to get them there them over to Europe and can have 3 times the number of armorers to prep and load them and assuming you can afford to replace B-17s on a one for one basis and that you have the additional ground crews to maintain the more complex aircraft.

Whether it's sailing west or east, the shipping exists all the same, right? The armorers are still trained, and could work in Europe rather than the Marianas depending on how you want to split the force of B-29s by theater. Ditto the ground crews.

There won't be replacing B-17s with B-29s one-for-one, I don't think, given how many 8th AF had of the former on hand.

The HE bombs used in ETO could be the bottleneck, sure. So could a lack of suitable runways.

Explosives production is a difficult process and there was a lot of completion for the ingredients. Tripling the number of bombs produced is not an option.

The night bombing of japan was actually halted for a time because they ran out of bombs

It wouldn't be easy.

 

[swampyankee]

Assuming there is the capacity to make 3 times the number of bombs and the shipping space to get them there them over to Europe and can have 3 times the number of armorers to prep and load them and assuming you can afford to replace B-17s on a one for one basis and that you have the additional ground crews to maintain the more complex aircraft.

Explosives production is a difficult process and there was a lot of completion for the ingredients. Tripling the number of bombs produced is not an option.

The night bombing of japan was actually halted for a time because they ran out of bombs

They wouldn't need three times the number of bombs or three times the weight of explosives, nor would you need to replace B-17s one-for-one, any more than you would need to replace B-10s with B-17s one-for-one. You just need to maintain the same weight of bombs on target. The B-29 was faster and flew higher than either the B-17 or B-24; it would be a more difficult target to intercept so its loss rates would be significantly lower.

 

[XBe02Drvr]

The technology of the day i.e. analog computers based on tubes and mechanical interfaces was not the seamless control technology we know today.

The trainer I maintained and operated in the Navy was 17 cabinets full of tubes, servos, synchros, and fat 100 conductor cables with Cannon plugs; the mother of all analog computers. Not a digital bone in its body. Seamless, it was not.

 

[GrauGeist]

The technology of the day i.e. analog computers based on tubes and mechanical interfaces was not the seamless control technology we know today.

The average cellphone today, has infinitely more computing power than the Apollo 11's onboard computer system of the 60's.

Which, by the way, was advanced for it's time with 32K Bits RAM and 72Kb ROM run by a .043Mhz processor.

So yes, an analog computer from the 40's would have been considerably different and complex.

 

[Reluctant Poster]

They wouldn't need three times the number of bombs or three times the weight of explosives, nor would you need to replace B-17s one-for-one, any more than you would need to replace B-10s with B-17s one-for-one. You just need to maintain the same weight of bombs on target. The B-29 was faster and flew higher than either the B-17 or B-24; it would be a more difficult target to intercept so its loss rates would be significantly lower.

You are saying much the same thing as I am. The point I was trying to make is that you can't replace B-17s and 24s with B-29s on a one-to-one basis. The idea that you will have 3 times as many bombs (I'm not sure what that 3 to 1 ratio is actually based on) to drop to make up for inaccuracies due to higher altitudes wouldn't be true in practice.

Your second assertion that the loss rate would be lower is based on the assumption that the B-29 stood up to damage as well as the B-17. There is evidence to suggest it didn't.

Your assertion inspired me to find my copy of The Rand Corporation Paper RM-402 "Aircraft Vulnerability in World War II". Section IV "Single Hit Probability and Vulnerable Areas" calculates, amongst other things, the single hit probability of a kill due to antiaircraft fire. For very heavy and heavy bombers the results are as follows:

B-29 0.020

B-17 0.009

B-24 0.015

The B-17 is half as likely to be lost. It richly deserves its reputation as a rugged aircraft

The paper also includes a table calculating loss rates for B-29 missions over Japan at various altitudes. I have recreated the table below.

I was surprised to see how little loss rates varied with altitude for daylight missions over Honshu. I was not surprised to see that loss rate from all causes increases with altitude. The strain on engines due to long climbs is widely documented. The other item that sticks out is the dramatic increase in flak damage due to flying below 20,000 feet.

This bolsters my contention that you should fly high enough to avoid the worst effects of flak but no higher. That's what they ended up doing over Japan.

 

[SaparotRob]

The trainer I maintained and operated in the Navy was 17 cabinets full of tubes, servos, synchros, and fat 100 conductor cables with Cannon plugs; the mother of all analog computers. Not a digital bone in its body. Seamless, it was not.

Great post. I accidentally hit the reply button laughing while reading the last sentence.

 

[chipieal]

In answer to fast mongerel. I do not think based on prevailing thought in the mid 20th century that America would have ever used the A bomb on Germany. These are only my opinions 1) The close proximity to other friendly allied nations that could potentially be affected by whatever would have been the aftermath. i have read that Dr. Oppenheimer predicted what we call nuclear fallout might have happened. Could you imagine the fall out if we killed civilians after the bomb blasts in England or France? 2) The prevailing thought in Western European countries was that Orientals were expendable - do not matter and who cares about their safety. After all look at Pearl Harbor, Singapore, the Philippines all atrocities against WESTERN POWERS. In the prevailing thought of the early 1940's Japan deserved this for daring to challenge The European Powers. 3) Japan is relatively isolated from other countries. Again who cares about Korea or China. Again just my opinion.

 

[Thumpalumpacus]

1) The close proximity to other friendly allied nations that could potentially be affected by whatever would have been the aftermath. i have read that Dr. Oppenheimer predicted what we call nuclear fallout might have happened. Could you imagine the fall out if we killed civilians after the bomb blasts in England or France?

England and France probably wouldn't have been affected. The weather patterns run generally west-to-east in Europe.

That doesn't negate your point, but I still don't know that the Allies would have cared much. I doubt Stalin would have complained either, even though his troops would be under that fallout.

2) The prevailing thought in Western European countries was that Orientals were expendable - do not matter and who cares about their safety. After all look at Pearl Harbor, Singapore, the Philippines all atrocities against WESTERN POWERS. In the prevailing thought of the early 1940's Japan deserved this for daring to challenge The European Powers. 3) Japan is relatively isolated from other countries. Again who cares about Korea or China. Again just my opinion.

Germany was seen as the strongest of the Axis. I think if a working A-bomb had preceded Germany's surrender, Germany would still have been the first target. This is, of course, well into what-if territory and not really pertinent to the thread's topic at any rate.

 

[GrauGeist]

Germany was most certainly considered for the A-bomb.
Their early defeat was also their salvation.

In regards to fallout, the A-bombs dropped on Japan produced little in the way of fallout due to the altitude they were detonated at coupled with their yeild.

 

[swampyankee]

The atomic bomb was developed to attack Germany, so it was certainly considered.

Fallout is, of course, a consideration today but radiation dangers were not well known in 1945, so I think it unlikely that radiation and fallout would be a consideration

 

[Reluctant Poster]

You are saying much the same thing as I am. The point I was trying to make is that you can't replace B-17s and 24s with B-29s on a one-to-one basis. The idea that you will have 3 times as many bombs (I'm not sure what that 3 to 1 ratio is actually based on) to drop to make up for inaccuracies due to higher altitudes wouldn't be true in practice.

Your second assertion that the loss rate would be lower is based on the assumption that the B-29 stood up to damage as well as the B-17. There is evidence to suggest it didn't.

Your assertion inspired me to find my copy of The Rand Corporation Paper RM-402 "Aircraft Vulnerability in World War II". Section IV "Single Hit Probability and Vulnerable Areas" calculates, amongst other things, the single hit probability of a kill due to antiaircraft fire. For very heavy and heavy bombers the results are as follows:

B-29 0.020

B-17 0.009

B-24 0.015

The B-17 is half as likely to be lost. It richly deserves its reputation as a rugged aircraft

The paper also includes a table calculating loss rates for B-29 missions over Japan at various altitudes. I have recreated the table below.


View attachment 642275


I was surprised to see how little loss rates varied with altitude for daylight missions over Honshu. I was not surprised to see that loss rate from all causes increases with altitude. The strain on engines due to long climbs is widely documented. The other item that sticks out is the dramatic increase in flak damage due to flying below 20,000 feet.

This bolsters my contention that you should fly high enough to avoid the worst effects of flak but no higher. That's what they ended up doing over Japan.

The average cellphone today, has infinitely more computing power than the Apollo 11's onboard computer system of the 60's.

Which, by the way, was advanced for it's time with 32K Bits RAM and 72Kb ROM run by a .043Mhz processor.

So yes, an analog computer from the 40's would have been considerably different and complex.

Here is the best explaination for how the system was used.

 

[Reluctant Poster]

You are saying much the same thing as I am. The point I was trying to make is that you can't replace B-17s and 24s with B-29s on a one-to-one basis. The idea that you will have 3 times as many bombs (I'm not sure what that 3 to 1 ratio is actually based on) to drop to make up for inaccuracies due to higher altitudes wouldn't be true in practice.

Your second assertion that the loss rate would be lower is based on the assumption that the B-29 stood up to damage as well as the B-17. There is evidence to suggest it didn't.

Your assertion inspired me to find my copy of The Rand Corporation Paper RM-402 "Aircraft Vulnerability in World War II". Section IV "Single Hit Probability and Vulnerable Areas" calculates, amongst other things, the single hit probability of a kill due to antiaircraft fire. For very heavy and heavy bombers the results are as follows:

B-29 0.020

B-17 0.009

B-24 0.015

The B-17 is half as likely to be lost. It richly deserves its reputation as a rugged aircraft

The paper also includes a table calculating loss rates for B-29 missions over Japan at various altitudes. I have recreated the table below.


View attachment 642275


I was surprised to see how little loss rates varied with altitude for daylight missions over Honshu. I was not surprised to see that loss rate from all causes increases with altitude. The strain on engines due to long climbs is widely documented. The other item that sticks out is the dramatic increase in flak damage due to flying below 20,000 feet.

This bolsters my contention that you should fly high enough to avoid the worst effects of flak but no higher. That's what they ended up doing over Japan.

The attached document discuses the effectiveness of the low level bombing campaign. It lists several reasons why lower is much better. As has been mentioned the winds are less severe but that is only part of the story. Japan and Germany both shared the same problem of poor visibly. If you read the other papers on 8th AF bombing accuracy I preciously posted you will see that over Germany accuracy suffered greatly because most days were cloudy. As consequence in both theaters high level bombing was predominantly by by radar. The attached paper states quite clearly that the radar of the B-29 was very not very accurate at high altitudes.
One of the more interesting findings of the paper was that individual aircraft bombing the target (ie RAF Bomber Command style) was much more accurate than the USAAF lead bomber method.

As an aside LeMay didn't come up with idea of using B-29s at night. That had already been planed for before he showed up in the theater. The first two raid by B-29s on Japan (from bases in China) were at night (Yawata and Nagasaki).

Also the fire bombing of Japanese cites was planned well before B-29 arrived in theater. The US built a model Japanese city a year before to see how well it would burn.

The Japanese Village at Dugway Proving Ground: An Unexamined Context to the Firebombing of Japan - The Asia-Pacific Journal: Japan Focus

[…]

apjjf.org

The first fire bombing raid was actually on the Chinese city of Hankow. Apparently 1/2 the bombs missed the target area and landed in residential areas. Not a lot of information seems exists on the raid but some sources claim up to 20,00 Chinese died.