B29 with only tail guns

[MacArther]

I've heard that late in the bombing offensive over Japan, some B-29's were stripped of all defensive weapons except their tail guns to save weight and increase speed and bomb load. Supposedly, this was mostly used with the low level fire-bombing raids. My question is: At lower levels, wouldn't the crew be more vulnerable if they didn't have the extra guns to ward away beam or head on attack by Japanese interceptors?

 

[swampyankee]

While Lemay was certainly a cold-blooded SOB, he was no fool. Stripping the guns (and, presumably, the gunners that the removed guns required) probably improved payload enough that even if there was effective fighter opposition, the net loss of crews would be less.

Logic? Say the removed guns (and any dedicated gunners) and ammunition total 2,000 lb. Either the aircraft take-off 2,000 lb lighter, meaning that fewer crash on take-off, so fewer crew deaths before aircraft are anywhere near the target, or they take-off with 2,000 lb more bombs, meaning that fewer sorties are needed for the same damage, and fewer crews are lost, even if the loss rate is somewhat increased (2,000 lb was what -- maybe 15% of a typical bomb load?). Overall, I suspect the increase in loss rate would be small: fighter escorts were much more important to protect the bombers than were the bombers' self-defense armament, which is why US bomber designs pretty much got rid of everything except the tail gun (note the B-36's design was started before the Japanese attack on Pearl Harbor and was probably fixed before the bomber offensive demonstrated the futility of bomber self-defense.

 

[davebender]

Japanese night air defense was nothing like that which existed over Germany during 1942 to 1945. Otherwise U.S. heavy bomber barons would have made different decisions in the Pacific.

 

[swampyankee]

Japanese night air defense was nothing like that which existed over Germany during 1942 to 1945. Otherwise U.S. heavy bomber barons would have made different decisions in the Pacific.

That may be the case. It is also possible that given a significant fighter threat, it may be better for crew morale if the bomber can shoot back even if it is to the detriment of net military effectiveness. Post-war, when the services were able to better evaluate claimed vs actual losses to bombers' defensive guns, the western powers pretty much eschewed heavy defensive armament on their bombers; no jet-powered US bomber had more than a tail turret. I would expect that this was because the bombers' defensive armament was found to be a net detriment to the aircraft's military effectiveness, including increasing the net number of casualties.

 

[drgondog]

With poor radar and even poorer night fighter defenses, visualize how hard it woul be to craft and execute a head on attack?

Which leaves 5-7 o'clock approach on an airplane nearly as fast as the pursuing fighter. If the Jap interceptor can get a vector

 

[glennasher]

Yep, the B-29 was faster by far than a B-17 or B-24, and the Japanese interceptors had a hard time catching them. At night, it was even more difficult.

 

[Shinpachi]

Japanese fighters were banned to fly to save their limited fuel.
They were only waiting for the allies landing on the Japanese coasts.
Gen. Lemay knew it very well.
He was a genius of war.

 

[syscom3]

The B29 crewman at the B29 website said Lemay said one thing and crews did another. They usually kept a couple turrets complete with guns and ammo.

 

[GrauGeist]

There were several Japanese pilots and units that did well against the B-29, here's a few notable pilots:

Lt. Hannoshin Nishio, 2nd Chutai/4th Sentai flying the KI-45 - 5 confirmed

Capt. Yoshio Yoshida, 3rd Chutai/70th Sentai flying the KI-84 - 6 confirmed, 1 probable

M/Sgt. Isamu Sasaki, Army Test Center, Fussa Airfield flying the KI-84 - 6 confirmed (3 in one night, 25 May 1945), 3 probable

2nd Lt. Makoto Ogawa, 3rd Chutai/70th Sentai flying the ki-44-II - 7 confirmed

WO Sadamitsu Kimura, 2nd Chutai/4th Sentai flying the KI-45 (modified with two 70° mounted Ho-5 20mm) - 8 confirmed

Capt. Fujitaro Ito, 3rd Chutai/5th Sentai flying the KI-45/KI-100 - 9 confirmed

 

[Rufus123]

There were several Japanese pilots and units that did well against the B-29, here's a few notable pilots:

Lt. Hannoshin Nishio, 2nd Chutai/4th Sentai flying the KI-45 - 5 confirmed

Capt. Yoshio Yoshida, 3rd Chutai/70th Sentai flying the KI-84 - 6 confirmed, 1 probable

M/Sgt. Isamu Sasaki, Army Test Center, Fussa Airfield flying the KI-84 - 6 confirmed (3 in one night, 25 May 1945), 3 probable

2nd Lt. Makoto Ogawa, 3rd Chutai/70th Sentai flying the ki-44-II - 7 confirmed

WO Sadamitsu Kimura, 2nd Chutai/4th Sentai flying the KI-45 (modified with two 70° mounted Ho-5 20mm) - 8 confirmed

Capt. Fujitaro Ito, 3rd Chutai/5th Sentai flying the KI-45/KI-100 - 9 confirmed

I looked up the speeds on the Japanese aircraft. It looks like they had very low closing speeds. How did the manage to catch the bombers? I am not doubting at all the did this but it sounds hard.

 

[GrauGeist]

The max speed for the B-29 is 357mph (574kph) but this is an optimum speed. Fully loaded and they'll be doing less.

KI-44-II max speed: 376mph (605kph)
KI-45 max speed: 336mph (540kph)
KI-84 max speed: 427mph (687kph)
KI-100 max speed: 360mph (580kph)

These pilots were catching the B-29s inbound, which will be travelling slower than thier maximum possible speed. Many of the pilots were already at altitude waiting, so they dove in for the attack.

You'll notice that WO Kimura was flying a "slower" twin-engined aircraft (KI-45) with successful results, because he was catching the B-29s fully loaded inbound. Well, he also had a Japanese version of "Schrage Musik"...that really helped.

 

[Rufus123]

The max speed for the B-29 is 357mph (574kph) but this is an optimum speed. Fully loaded and they'll be doing less.

KI-44-II max speed: 376mph (605kph)
KI-45 max speed: 336mph (540kph)
KI-84 max speed: 427mph (687kph)
KI-100 max speed: 360mph (580kph)

These pilots were catching the B-29s inbound, which will be travelling slower than thier maximum possible speed. Many of the pilots were already at altitude waiting, so they dove in for the attack.

You'll notice that WO Kimura was flying a "slower" twin-engined aircraft (KI-45) with successful results, because he was catching the B-29s fully loaded inbound. Well, he also had a Japanese version of "Schrage Musik"...that really helped.

I see, I was picturing closing speeds and thought to overtake would be so slow they would be subjected to defensive fire for too long of a period of time and escorts would have plenty of time to assist the bombers.

Having altitude in advance and diving on them, I can see that getting them.

 

[drgondog]

At night a B-29 far easier to spot than say a Ki 84 behind it - then shallow dive and close just below and behind it for a raking shot underneath at the engines and wings.

 

[drgondog]

Japanese fighters were banned to fly to save their limited fuel.
They were only waiting for the allies landing on the Japanese coasts.
Gen. Lemay knew it very well.
He was a genius of war.

I doubt that Allied intelligence would know that - particularly in light of the Kamikaze attacks at Okinawa. Also night fighter attacks would be a lesser force than a day attack and much lower altitude so fuel consumption would be less for night defense.

 

[drgondog]

There were several Japanese pilots and units that did well against the B-29, here's a few notable pilots:

Lt. Hannoshin Nishio, 2nd Chutai/4th Sentai flying the KI-45 - 5 confirmed

Capt. Yoshio Yoshida, 3rd Chutai/70th Sentai flying the KI-84 - 6 confirmed, 1 probable

M/Sgt. Isamu Sasaki, Army Test Center, Fussa Airfield flying the KI-84 - 6 confirmed (3 in one night, 25 May 1945), 3 probable

2nd Lt. Makoto Ogawa, 3rd Chutai/70th Sentai flying the ki-44-II - 7 confirmed

WO Sadamitsu Kimura, 2nd Chutai/4th Sentai flying the KI-45 (modified with two 70° mounted Ho-5 20mm) - 8 confirmed

Capt. Fujitaro Ito, 3rd Chutai/5th Sentai flying the KI-45/KI-100 - 9 confirmed

Dave - of the above I suspect only the Ki 44 and 45 were likely involved in night attacks unless the history states otherwise.

 

[GrauGeist]

Bill, they did mention in some cases that night attacks were involved, particulary M/Sgt. Sasaki, who would wait to spot the silouette of the B-29 against the burning city and dive down from above.

There were mentions of beam, head-on and diving attack methods, much like the Luftwaffe employed against the heavies over Europe.

 

[Shinpachi]

I doubt that Allied intelligence would know that - particularly in light of the Kamikaze attacks at Okinawa. Also night fighter attacks would be a lesser force than a day attack and much lower altitude so fuel consumption would be less for night defense.

Nice comments getting to the points, drgondog.

I don't know if Gen. Lemay obtained information relating to the Japanese flight-bans as well as fighters evacuation from Tokyo avoiding combats with the P-51s but his decison flying the B-29s with no guns was excellent. So, I said he was a genius.

In the final stage of war, say since fall of Okinawa, Japanese military abandoned formal interception against attacks from the sky as major production facilities and children had been moved to the countryside. They were preparing for the coming homeland battle with no hope.

 

[drgondog]

Dave - diving at B-29s silhouetted against fires was a double edged sword as the light below would illuminate fighters above.

 

[GrauGeist]

You would think so, Bill, though I'm not sure about the camo scheme of the defending Chutai/Sentai involved in those night actions. I'd have to dig around and find the book that covers the Japanese B-29 hunters again to see.

 

[Jabberwocky]

I found the following weights for the B-29's remote turrets:

Front upper: 879 kg (1,938 lb) fully loaded
Others: 612 kg (1,350 lb) fully loaded.

Not sure if that is with gunners included or not, but I'd guess not.

Delete four turrets and you'd cut at least 6000 lbs. Take another 880 lbs out for the gunners themselves and you're at almost 6900 lbs in weight savings. Probably more, once you remove all the ancillaries, heating systems, radios, lead calculating computers and the like.

On an aircraft that weighs 74,500 empty, that's almost a 10% weight reduction.