Mosquito - the alternative strategic bomber

[wuzak]

Since no Mosquito ever flew using either Merlin XX (Merlin 21,23,and 25 differed in detail from the XX but not in performance) or Merlin 61 engines this would be estimated performance using those engines as a reference point.

W4050 did fly with Merlin 61s. First flight June 20 1942, short wingspan, short nacelles and short No 1 tailplane. Fitted with snow guards on the intake it achieved 428mph @ 28,500ft and without snow guards 437mph @ 29,200ft.

Of course the main difference between the 21 and the XX was the reversed flow cooling system. This was installation specific, but otherwise the 21 was as the XX.

 

[stona]

W4050 did fly with Merlin 61s. First flight June 20 1940,.

Surely not 1940!!!!!

I think you meant 1942.

On the second flight, in the configuration described, the aircraft supposedly reached 40,000 ft, but tail buffeting occurred and subsequently, at the end of the month, long nacelles and a No. 2 tailplane were fitted.

The Merlin 61 seems to have been by-passed in production Mosquitoes, maybe required for Spitfires? The next variants were Merlin 72/73 or Merlin 76/77 powered.

Cheers

Steve

 

[wuzak]

Surely not 1940!!!!!

I think you meant 1942.

On the second flight, in the configuration described, the aircraft supposedly reached 40,000 ft, but tail buffeting occurred and subsequently, at the end of the month, long nacelles and a No. 2 tailplane were fitted.

The Merlin 61 seems to have been by-passed in production Mosquitoes, maybe required for Spitfires? The next variants were Merlin 72/73 or Merlin 76/77 powered.

Cheers

Steve

Yes, I meant 1942. Fixing it now!

 

[Hop]

Does the report refer to 'cookies' that is High Capacity bombs? Not all 4,000lb bombs were 'cookies'.

Steve

It doesn't specify which type of 4,000 lb bomb, but the only likely options were the 4,000 lb High Capacity (cookie) or 4.000 lb Medium Capacity. The Mosquito could drop either, but according to Harris, the MC bomb wasn't used much by the heavies, and most were dropped by Mosquitoes.

The two raids in question were carried out by heavies (there were 8 Mosquitoes on the first one, which I presume were pathfinders) so the bombs were almost certainly cookies.

In general, destroying buildings and machinery required lots of explosive. The shrapnel from bomb cases wasn't effective against buildings or machinery. Against a really hardened target with several feet of concrete a cookie would be ineffective, but "reinforced" factory and plant buildings couldn't withstand the explosion of 3,000 lb of HE in contact with the building.

 

[stona]

27th September. Bottrop. 175 aircraft attacked (96 Halifaxes, 71 Lancaster, 8 Mosquitoes). Bombing on Oboe place sky markers due to conditions. Some aircraft bombed through gaps in the cloud. No losses.

31st October. Bottrop. 101 Lancasters of 3 Group carried out a G-H attack on the oil plant.

The 11 hits mentioned by the USSBS were the result of bombing by at least 275 aircraft, and this, in the context of the thread, is the problem facing the Mosquito and its relatively light bomb load. If I had to bet I'd put my money on the damage being done on the second raid, as bombing on sky markers was usually relatively inaccurate.

Cheers

Steve

 

[Shortround6]

W4050 did fly with Merlin 61s. First flight June 20 1942, short wingspan, short nacelles and short No 1 tailplane. Fitted with snow guards on the intake it achieved 428mph @ 28,500ft and without snow guards 437mph @ 29,200ft.

Of course the main difference between the 21 and the XX was the reversed flow cooling system. This was installation specific, but otherwise the 21 was as the XX.

Thank you. Main difference between a Merlin 61 and a Merlin 72 was the cooling system, although the 72 was rated for higher boost. First two stage reverse flow Merlin being the Merlin 67 although that was built in small numbers (under 75?) and Lumsden does not list any aircraft fitted with it?

 

[tomo pauk]

27th September. Bottrop. 175 aircraft attacked (96 Halifaxes, 71 Lancaster, 8 Mosquitoes). Bombing on Oboe place sky markers due to conditions. Some aircraft bombed through gaps in the cloud. No losses.

31st October. Bottrop. 101 Lancasters of 3 Group carried out a G-H attack on the oil plant.
...

<shivers>

Brabus immeditely comes to mind of a proper gearhead

 

[wuzak]

I have a book, Simons, Mosquito, the Original Multi-Role Combat Aircraft, which has a list of what was carried by Mosquito bombers during the war.

It lists 3 types of 4000lb bomb - the 4,000lb HC, around 770-780 of those, the 4,000lb MC of which 141 were dropped, and a 4,000lb M2 of which some 6-7,000 were used.

I am wondering if the M2 is the Mk II version of the 4,000lb HC?

It also lists some incendiaries, including the 4lb Mk 14 and 15, which were used in bundles.

I will put up the list when I get home.

 

[wuzak]

Aozora posted the bomb chart a few years ago:

WW2 Strategic Bomber Characteristics

 

[stona]

It also lists some incendiaries, including the 4lb Mk 14 and 15, which were used in bundles.
.

I'm not sure why he refers to 'Mk' 14 and 15 incendiaries. The Mark, usually given as 'Number' in ORBs, refers to the bundle/cluster not the bombs of which most were versions of the Mk. IV incendiary. I mentioned earlier in this thread that the No. 14 cluster was 158 x 4lb incendiaries, a No. 15 cluster was 104 of the same. The incendiary bombs had a hexagonal shape, making them easy to bundle.
Armourers liked these as otherwise they had to load each bomb individually into the SBCs. When we consider the 80,000,000 x 4lb incendiaries dropped that's a lot of loading!

Around 10,000 x 4,000lb bombs dropped is the figure usually attributed to the Mosquito, so the figures you give are in the ball park.
Mosquitoes under Bomber Command flew 39,795 sorties during the war and dropped just over 10% of all 4,000 lb bombs, a significant contribution given their numbers.
Bomber Command dropped a total of about 90,000 x 4,000 lb bombs of various types during the war, principally HC (68,000) and MC (21,000).

I think M2 does refer to the Mk II version, and probably of the HC bomb but it is not clear (the MC bomb had Mks. I and II in service too).
Maybe someone will find some clarification, I'm not familiar with the M2 designation.

Cheers

Steve

 

[wuzak]

WW2Equipment lists the number of 4,000lb HC bombs used as 93,245.

The breakdown given is:
1941 531
1942 4,335
1943 25,476
1944 38,035
1945 24,868

The site also states that "Over 21,000 4,000lb MC bombs were dropped by Bomber Command with 13,000 of these being dropped in 1944." on the page for the 4,000lb MC bomb.

Sharp and Bowyer agree with Simons on the numbers of HC, MC and M2 bombs used by the Mosquito, as well as the 8 4,000lb IBs!

Both agree that 141 4,000lb MC bombs were dropped, which isn't a lot. I know that some were used on an attack on an oil refinery about the middle of 1944. I will have to check the ORBs I have to see which squadron.

Sharp and Bowyer list the number of incendiary clusters dropped as 6,678 x Mk 14 (106 x 4lb) and Mk 15 and 3,160 x Mk 15 (158 x 4lb).

 

[wuzak]

109 squadron dropped some 4,000lb MC bombs on Homburg in the night of 25/26 June 1944.

 

[stona]

I think the figures all tally fairly well. I took my numbers from MacBean and Hogben (Bombs Gone).

They are also quoted in the RAF Historical Society Journal from time to time, when the subject comes up. Journal 45 has some good stuff on this and related subjects.

Cheers

Steve

 

[stona]

Flicking through the book above I came across an illustration of a 'Cluster Projectile 500 lb no. 14', the one containing 106 x 4lb incendiaries, sometimes referred to as 'aimable bomb clusters'.

The authors (who know a thing or two about British ordnance) make the following comments.

"The latter's effectiveness [4 lb incendiary] improved enormously in 1944, when it was dropped in aimable bomb clusters. These disintegrated at low-level altitude, permitting greater concentrations of the contained bombs (child stores), rather than showering them down from small bomb containers (attached to the aircraft) from high altitude. The advent of the clusters also largely circumvented the possibility of a bomber at higher level inadvertently hitting his colleagues flying below with, in the case of the Lancaster, something like 3,000 four pounders."

A two squadron bomber station like East Kirkby (Nos. 57 and 630 Squadrons), where one of the authors was the armaments officer in 1944, typically loaded 190 tons of ordnance on its 35-40 four engine bombers everyday. This is what they wrote about the workload imposed by the incendiaries.

"Incendiary bombs produced the greatest workload, many hours being expended in unboxing well sealed four pounders and restowing them in Small Bomb Containers for carriage on the aircraft. The advent of made-up clusters of incendiaries in 1944 eased that burden somewhat."

Cheers

Steve