USAF 1944: ideal multi-purpose 2-engined aircraft?

[Shortround6]

Uh, Tomo, you are using for bomb handlers, elasticman?

Somebody has got to be able to reach the bomb shackles and check that they are latched AND rig the safety wires that run from the bomb mount to the fuses (usually run from a point between the bomb shackles through them and then to the nose and tail fuses). The safety wires pull pins from the fuses as the bomb is dropped (leaves the bomb mount/plane shackle) 'arming" the bomb.

On the smaller bombs it may be possible to sneak a couple of hands/arms around the side of the bomb between the bomb bay walls and do this work blind (or with a mirror?) but on the big bombs nobody's arms are long enough. You need to be able to get a head and body (even a skinny one) between the bomb and the bomb bay wall, or try to work through access hatches in the bomb bay 'ceiling' which may be the part of the wing structure. Hatches between spars or other structural components. Assuming of course you don't have fuel tanks over the bomb bay.

Bombs are hoisted into the bomb bay (as are under wing bombs) by winches.

The bomb bay needs to have room for the men to work, even if cramped and inconvenient, not be almost a press fit for the bomb in question.

 

[tomo pauk]

Fair points. Is there any info about how easy/hard the cookie was hoisted on a rack in the Mossie - should also need the help of Elasticman?
The 36in wide bomb bay would indeed be unnecessary a tight one - just for 2 x 1000 lbs bombs, one aside to another, it would need to be at least 40 in wide, better make it 45?

Is that really a 4000lb bomb? Looks altogether too small (short) to me.

Check out the pdf docs, SR6 provided the links here.

 

[Shortround6]

Mossie bomb bay was wider than it was tall. this is a FB bomb bay but should give the idea.

 

[snowmobileman]

I have several thoughts on this subject: first off, the bomber version of the Mosquito was unarmed, and thus faster than the FB versions (as well as all of the U.S. bombers/attack aircraft). From memory, I recall the FB versions top speeds as being under 400 mph. Second thought: no one has mentioned the XA-26D, which was essentially an up-engined version of the A-26B with a listed top speed of 403 mph. The first one was accepted Jan. 31, 1945, so it might have flown in 1944.

 

[tomo pauk]

Indeed you're right about the 'fighter' Mosies being slower than bombers, on same engines. Difference being 10-15 mph, see here. The fastest NF Mossie was the (experimental?) XV, with only 4 LMGs under belly, if I'm reading the report right. The speed would've been the same with internal cannons, no LMGs?
The XA-26D and XA-26F were outfitted with R-2800-83, the 'C' series engine, that was not available in our time frame. The -83 was the equivalent of the R-2800-34W, the engine used in the F7F-3 and F8F-1. The difference in power at altitude was considerable vs. 'regular' A-26B engines of 1944 - 1700 HP at 16000 ft (and 1850 HP at 15500, war emergency rating), vs. 1600 HP at 13500 ft. However, the A-26 with 2-stage R-2800 'B' was proposed here (or turbo, for a good measure), it would provide even more power at altitude than the 2800-83.

 

[OldSkeptic]

I'm sure they used, albeit rarely, 3,000lb 'normal' bombs in the bulged bay Mossies. 6x500lb from memory in a sort of holder.
No idea about a possible 3x1,000lb though. Unless I have it around the wrong way of course.

But doctrine matters here. The RAF's Bomber Command (agreed by Churchill) one was to 'de-house' working class people (and kill quite a few, hopefully a lot). Therefore the 4,000lb cookie combined with incindiaries was they way they preferred, the bomb to blow the roofs off, then start the fires. They were never, except for limited missions, interested in hitting anything (except houses) to actually damage them.
If they had a different doctrine, as per the Luftwaffe, the USAAF the Soviets and the Japanese, then I'm sure they would have found a way to fit more normal bombs in.

 

[wuzak]

I'm sure they used, albeit rarely, 3,000lb 'normal' bombs in the bulged bay Mossies. 6x500lb from memory in a sort of holder.
No idea about a possible 3x1,000lb though. Unless I have it around the wrong way of course.

Avro developed, reportedly, the carrier which would allow 6 x 500lb bombs. Doubtful whether it was used operationally.

And for a 3000lb load, two 500lb GP/MC could be carried under the wings on later models. (Max bomb load listed on the data sheet for the B.XVI is 5000lb - 1 X 4000lb + 2 x 500lb).

But, as you say:

But doctrine matters here. The RAF's Bomber Command (agreed by Churchill) one was to 'de-house' working class people (and kill quite a few, hopefully a lot). Therefore the 4,000lb cookie combined with incindiaries was they way they preferred, the bomb to blow the roofs off, then start the fires. They were never, except for limited missions, interested in hitting anything (except houses) to actually damage them.
If they had a different doctrine, as per the Luftwaffe, the USAAF the Soviets and the Japanese, then I'm sure they would have found a way to fit more normal bombs in.

Part of that doctrine required large bomb loads, the size of which the Lancaster could carry.

Mosquitoes, therefore were used as target markers and pathfinders, or for diversionary raids, where the 4000lb blast bomb lent an air of authenticity.

SR says that the 1600lb AP bomb looked good in brochures. You could probably produce such a brochure for the Mosquito, considering that the Mossie could carry a pair of British 1000lb MC or 1000lb GP, both of which were larger (at least in width/diameter) than the 1600lb AP bomb.

The Mossie could probably even carry two of the British 2000lb AP bombs.

btw, I'd love to see the dimensions of the 4000lb test model for Tallboy and Grand Slam. The main problem there, I would think, would be length .

 

[oldcrowcv63]

Interesting Wikipedia Quote:

"Production plans and American interest

The Air Ministry had authorised mass production plans to be drawn up on 21 June 1941, by which time the Mosquito had become one of the world's fastest operational aircraft.[6] The Air Ministry ordered 19 photo-reconnaissance (PR) models and 176 fighters. A further 50 were unspecified; in July 1941, the Air Ministry confirmed these would be unarmed fast bombers.[6] By the end of January 1942, contracts had been awarded for 1,378 Mosquitos of all variants, including 20 T.III trainers and 334 FB.VI bombers. Another 400 were to be built by de Havilland Canada.[55]
On 20 April 1941, W4050 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 were US General Henry H. Arnold and his aide Major Elwood Quesada, who wrote "I ... 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."[40][56]
The trials set up future production plans between Britain, Australia and Canada. The Americans did not pursue their interest. It was thought the Lockheed 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 Forces to learn from the design if they chose not to adopt it. Several days after the attack on Pearl Harbor, the USAAF then requested one airframe to evaluate on 12 December 1941, signifying that the USAAF realised that they had entered the war without a fast dual-purpose reconnaissance aircraft.[54]"

So is there a simple reason why the P-38 had such difficulty in becoming effective while the Mossy, every bit as fast, seems to have been a winner out of the gate? Or is the Mossy's history more complex? Did it have less trouble with compressibility effects and if so, why?

 

[Greyman]

So is there a simple reason why the P-38 had such difficulty in becoming effective while the Mossy, every bit as fast, seems to have been a winner out of the gate? Or is the Mossy's history more complex? Did it have less trouble with compressibility effects and if so, why?

Compressibility wouldn't be the issue. That's more of a fighter vs. fighter problem.

Where the P-38 couldn't compete with the Mosquito was range, cruise speed and altitude performance. I understand those early intercoolers in the P-38 were trouble.

 

[tomo pauk]

<snip>

So is there a simple reason why the P-38 had such difficulty in becoming effective while the Mossy, every bit as fast, seems to have been a winner out of the gate? Or is the Mossy's history more complex? Did it have less trouble with compressibility effects and if so, why?

IIRC the Beech aircraft company was approached with a request to produce Mosquito in the US, they replied that such a plane would've never worked?

Compressibility wouldn't be the issue. That's more of a fighter vs. fighter problem.

Where the P-38 couldn't compete with the Mosquito was range, cruise speed and altitude performance. I understand those early intercoolers in the P-38 were trouble.

Altitude performance of P-38 was equaled by Mosquito with 2-stage Merlins, the 1-stage engined Mossies were slower there. The P-38s with LE intercoolers were capable for ~400 mph at 25000 ft. Where P-38 comes in short is when it's tasked to act as a long-range fast bomber - under-slung bombs add to the drag, and cut the range.

 

[Greyman]

The P-38s with LE intercoolers were capable for ~400 mph at 25000 ft.

Yeah, that's the thing. The data seems to be a bit varied between what Lockheed said the aircraft could do and what the performance tended to be in-theatre.

I'm no student of the P-38's history though.

 

[tomo pauk]

While it's easy to prove that P-38 have had it's share of problems, Lochkeed was one of more honest manufacturers when it came down to what the plane was capable, when tested by costumer.

 

[Shortround6]

What was the dive limit speed on the Mosquito?

It may NOT have been allowed to dive at speeds that would get it into trouble ( welcome correction on that).

And while the Mossie was strong was it really rated for 'day fighter' maneuvers? Yes they did mix it up with Luftwaffe fighters but the P-38 was built to the US 8 "G" service, 12 "G" ultimate load strength standard ( clean and early models, later ones may have slipped a bit).
The Mossie was an amazing aircraft but the two were not built for the same purpose or to some of the same standards so even though they are both twin engined aircraft they each have strengths and weaknesses.

lets also try to compare like to like, as in 1942 P-38s to 1942 Mosquitos and 1944 P-38s to 1944 Mosquitos. Mosquitos with two stage Merlins don't show up in service (in more than single digits) until 1943 and depending on version, well into 1943.

 

[Greyman]

Generally a 450 mph dive limit and a 7.65 (positive) G limit at 19,200 pounds.

 

[tomo pauk]

The data to the left is for the Mossie FB.6, to the right is for the P-38D to -G (ie. no dive flaps). I was not able to find exactly the dive speed limitation for the Mossie, this is a general speed limit (how much does it change stuff?). Note that speeds are indicated, not true, and given in kts for the Mosquito.

 

[Greyman]

I have an A&AEE test of a Mosquito VI 'Diving Trials of Various Underwing Bombs'. The conclusions were:

'It is safe to dive to 450 mph ASI with bomb rack fairings on and with either 250lb or 500 lb GP bombs on.'

 

[Shortround6]

Hmmm, might be a bit embarrassing for the P-38 driver to passed out by a Mosquito that was carrying bombs outside

 

[CobberKane]

The whole thread kind of underscores what a remarkable design the mosquito was! doesn't it? I mean, had the Mossie never existed and someone had responded to this thread by saying "build the bomber with two Merlin's, make it as small as possible scrap all defensive arm armament and, oh, make it out of balsa and ply..." They would have been laughed off the forum.

 

[mhuxt]

I have an A&AEE test of a Mosquito VI 'Diving Trials of Various Underwing Bombs'. The conclusions were:

'It is safe to dive to 450 mph ASI with bomb rack fairings on and with either 250lb or 500 lb GP bombs on.'

Yes, the data posted above for the VI is from the post-war notes, with (reduced) post-war limitations.

 

[tomo pauk]

Is it stated on what altitude is safe to dive at 450 mph ASI?