8th Air Force use of Mosquitoes

[wuzak]

I might be a little late on this but a while back we discussed the Mosquito performing a high altitude mission in the same capacity the B-17 and B-24 accomplished. Remember that if you're bombing with a precision optical bomb sight, you are commencing you're bomb run at speeds just above cruising and I think you're probably looking at about 250 mph maximum. I know somewhere on here we posted the Mosquito's bomb door operating speed and it wasn't as high as you would expect.

In the case with a Mosquito, it would have been the same sitting duck over target as any heavy, American or British were while bombing unescorted. The advantage "would have" been after the bomb run where the Mosquito "could have" used superior speed to depart the combat area.

Found it..

"bomb bay doors open 305 knots" = 340 mph - not bad providing you're able to accurately bomb at that speed at altitude depending on wind and other conditions.

Pilot's Notes - De Havilland Mosquito FB 6

Here's a Norden bombsight page that talks about some other bombs sights and setting speeds.

NORDEN BOMBSIGHT

That is still 150-180mph faster than the 8th AF heavies would have been travelling on the bomb run.

The vulnerability is also dependent on the time required to fly straight and level. I believe for the Norden that this time was significant.

The bombers would also be very vulnerable if they just flew in at the same level, at the same speed and on the same heading one after the other, particularly if there were many of them. It would give the flak gunners time to adjust their settings (I believe the Germans only used time fuzes for much of the war).

 

[Shortround6]

The Germans used time fuses for just about the entire war on the big guns. There was a move back to contact fuses late in the war after a mathematician advanced a theory that the time fuses were introducing a bigger error than they solved. A long time of flight, 20-30 seconds, with even a tolerance of a few 10ths of a percent would have shells exploding several hundred feet short or long. Whatever they were gaining in near misses laterally was being lost to the vertical error of the fuses. Combat trials were held with results that confirmed the theory but it was too late in the war to be implemented on a wide scale.

 

[FLYBOYJ]

That is still 150-180mph faster than the 8th AF heavies would have been travelling on the bomb run.

The vulnerability is also dependent on the time required to fly straight and level. I believe for the Norden that this time was significant.

The bombers would also be very vulnerable if they just flew in at the same level, at the same speed and on the same heading one after the other, particularly if there were many of them. It would give the flak gunners time to adjust their settings (I believe the Germans only used time fuzes for much of the war).

That was only under perfect conditions. More than likely Mosquitoes used in the same capacity would have been bombing at speeds slightly higher than heavies. Look at the bomb sights as well, many of them weren't giving you more than 230 mph.

Bottom line you weren't getting any extra "value added" despite where where the Mosquito could have carried the same bomb load, dropped their load and ran away. Going into the target they will have offered at least a higher airspeed but still would have been at the mercy of German fighters. I'd bet dollars to donuts this whole scenerio was discussed by British and American brass several times during the war.

 

[wuzak]

That was only under perfect conditions. More than likely Mosquitoes used in the same capacity would have been bombing at speeds slightly higher than heavies. Look at the bomb sights as well, many of them weren't giving you more than 230 mph.

Bottom line you weren't getting any extra "value added" despite where where the Mosquito could have carried the same bomb load, dropped their load and ran away. Going into the target they will have offered at least a higher airspeed but still would have been at the mercy of German fighters. I'd bet dollars to donuts this whole scenerio was discussed by British and American brass several times during the war.

Not sure that the USAAF ever considered the Mosquito for a bombing role, much less a strategic bombing role. The RAF did, and there was a report prepared in 1943 which came to the conclusion that the Mosquito could perform the bombing more efficiently than the Lancaster - taking into account bombs on target, loss rates, economics related to materials and personnel, etc. But RAF Bomber Bommand was run by a man who was intent on destroying cities - for which the Lancaster was far more suitable, being able to carry a much bigger bomb load.

 

[Shortround6]

There is also the question of when did they know how effective some bombs really were. While even 500lb bombs were very good at blowing the roofs of factories they weren't so good at at actually wrecking the machinery in the factory. It turned out that many more bombs, or bigger bombs, or both were needed to truly knock a factory out of production for months, not just a few weeks or even days, than they originally estimated. Fires on the other had did knock factories out for extended periods.

How many bomb hits on a given sized factory (and what types of bombs) were really needed to take it out for an extended period of time and how should those bombs be delivered?

We are back to timing, did they know in the spring of 1942 (the latest that such a decision could be made) what types of bombs or mix of bombs gave the results desired and what type of planes cold best deliver them or were they still working on pre or early war experience or perceptions?
The fact that Mosquitoes could do pin point attacks at some point in 1944 with 4000lb bombs (of a type that may not have existed in 1942) doesn't really count.

 

[FLYBOYJ]

Not sure that the USAAF ever considered the Mosquito for a bombing role, much less a strategic bombing role. The RAF did, and there was a report prepared in 1943 which came to the conclusion that the Mosquito could perform the bombing more efficiently than the Lancaster - taking into account bombs on target, loss rates, economics related to materials and personnel, etc. But RAF Bomber Bommand was run by a man who was intent on destroying cities - for which the Lancaster was far more suitable, being able to carry a much bigger bomb load.

There is also the question of when did they know how effective some bombs really were. While even 500lb bombs were very good at blowing the roofs of factories they weren't so good at at actually wrecking the machinery in the factory. It turned out that many more bombs, or bigger bombs, or both were needed to truly knock a factory out of production for months, not just a few weeks or even days, than they originally estimated. Fires on the other had did knock factories out for extended periods.

How many bomb hits on a given sized factory (and what types of bombs) were really needed to take it out for an extended period of time and how should those bombs be delivered?

We are back to timing, did they know in the spring of 1942 (the latest that such a decision could be made) what types of bombs or mix of bombs gave the results desired and what type of planes cold best deliver them or were they still working on pre or early war experience or perceptions?
The fact that Mosquitoes could do pin point attacks at some point in 1944 with 4000lb bombs (of a type that may not have existed in 1942) doesn't really count.

Points taken

 

[davebender]

That depends on how you define "Low Level". 20mm weapons are most effective out to about 1,000 meters. Large bomber formations typically didn't attack from that low during WWII as it was suicidal.

Ploesti August 1, 1943
Operation Tidal Wave: Ploesti August 1, 1943
178 level bombers. Altitude of 200 feet.
54 aircraft lost. 30% loss rate.
Over 80% of the entire force suffered major damage. 1/6th of the bombers were in flyable condition after returning to base.

IMO 178 light bombers attacking the Krupp Gusstahlfabrik from an altitude of 200 feet are likely to have a similiar casualty rate. That might be worthwhile for a single attack on a high priority target but you cannot sustain a military campaign with casualty rates that high.

 

[Mustang nut]

The USA was certainly aware of the mosquitos performance from the start. The wing span was increased before production started to allow it to carry larger loads that the bomb bay could hold.

from thefullwiki

Official trials began at Boscombe Down on 19 February which satisfied the de Havilland company. On 20 April 1941 it was demonstrated to Lord Beaverbrook, the Minister of Aircraft Production. The Mosquito made a series of flights including one rolling climb on one engine. Also present was General Henry H. Arnold and his aide, Major Elwood Quesada:

I do recall the first time I saw the Mosquito as being impressed by its performance, which we were aware of. We were impressed by the appearance of the airplane that looks fast usually is fast, and the Mosquito was, by the standards of the time, an extremely well streamlined airplane, and it was highly regarded, highly respected.[28]



The trials set up future production plans between Britain, Australia and Canada. The Americans did not pursue their interest. It was thought the P-38 Lightning could handle the same duties just as easily. Arnold felt the design was being overlooked, and urged the strategic personalities in the United States Army Air Force to learn from the design if they chose not to adopt it. The USAAF then requested one airframe to evaluate, but this was only a few days before the Attack on Pearl Harbor, and the USAAF entered the war without a fast dual purpose reconnaissance machine
....................

However even the RAF wernt sold from the start on it as a bomber most of the initial order was for recon and fighter bomber types.

IMO 178 light bombers attacking the Krupp Gusstahlfabrik from an altitude of 200 feet are likely to have a similiar casualty rate. That might be worthwhile for a single attack on a high priority target but you cannot sustain a military campaign with casualty rates that high.

I agree dave, but if a lighter faster plane was used different tactics would be needed. A B17 could bomb reasonable accurately from altitude but a formation of boxes cant because they need to stay in formation. As others have said or implied I dont think the US military would have taken on the idea any time before the end of the war.

 

[davebender]

Historical results from December 1941 suggest otherwise.

Anchored IJA troop transports are about easiest possible military targets to find and hit. No heavy flak and minimal air cover. Why didn't B-17s operating from the Philippines and Java slaughter them?

 

[Mustang nut]

Historical results from December 1941 suggest otherwise.
Anchored IJA troop transports are about easiest possible military targets to find and hit. No heavy flak and minimal air cover. Why didn't B-17s operating from the Philippines and Java slaughter them?

Well bombing accuracy improved throughout the war with experience and better sights.

 

[davebender]

I am under the impression B-17 bombers were equipped with Norden bomb sights during 1941. Is that incorrect?

 

[wuzak]

That depends on how you define "Low Level". 20mm weapons are most effective out to about 1,000 meters. Large bomber formations typically didn't attack from that low during WWII as it was suicidal.

Ploesti August 1, 1943
Operation Tidal Wave: Ploesti August 1, 1943
178 level bombers. Altitude of 200 feet.
54 aircraft lost. 30% loss rate.
Over 80% of the entire force suffered major damage. 1/6th of the bombers were in flyable condition after returning to base.

IMO 178 light bombers attacking the Krupp Gusstahlfabrik from an altitude of 200 feet are likely to have a similiar casualty rate. That might be worthwhile for a single attack on a high priority target but you cannot sustain a military campaign with casualty rates that high.

I doubt that a Mosquito attack would in formation.

The advantage Mosquitoes would have over B-24s is that they would be moving faster and they present a smaller target. That said, the B-24 was probably the only aircraft that the Allies had which could bomb Ploesti from the bases that they had in North Africa.

 

[wuzak]

I seem to remember that the RAF didn't bomb in formation at night. Their formations were much looser than they 8th AF's, mainly because of the difficulty flying in such low proximity in the dark. They had some sort of system which allowed a lot of bombers to bomb individually in about an half hour.

 

[wuzak]

I am under the impression B-17 bombers were equipped with Norden bomb sights during 1941. Is that incorrect?

I do believe so. But whether the crews were fully up to speed in their use is another matter.

 

[Glider]

Lack of training was one reason given for the lack of accuracy. The RAF flew at least one daylight mission with the B17C, the role of bomb aimer taken by one of the American manufacturers demonstrators. The result, not only did they miss the target, they missed the town.

 

[Milosh]

Interesting article

The bombsight war: Norden vs. Sperry

http://thevaluesell.com/images/LSearle_bombsight.pdf

 

[davebender]

The V1 cruise missile was smaller and faster then a Mosquito light bomber. Cruising altitude was 2,000 to 3,000 feet. Yet the V1 casualty rate was as bad as the B-24 casualty rate over Ploesti.

Radar directed light flak was getting pretty effective by 1943. IMO 8th Air Force should stay above it. You will also avoid collisions with factory chimneys while flying through Ruhr Valley smog.

 

[Milosh]

Yes and the V-1 flew straight and level.

 

[davebender]

So will a Mosquito light bomber while over the target.

 

[Jabberwocky]

The V1 cruise missile was smaller and faster then a Mosquito light bomber. Cruising altitude was 2,000 to 3,000 feet. Yet the V1 casualty rate was as bad as the B-24 casualty rate over Ploesti.

Radar directed light flak was getting pretty effective by 1943. IMO 8th Air Force should stay above it. You will also avoid collisions with factory chimneys while flying through Ruhr Valley smog.

Comparing a cruise missile tavelling at a predictable path, speed and altitude to a manned aircraft an an independent navigation to a target is reaching.