WW2 Strategic Bomber Characteristics

[mhuxt]

As for duelling statistics, Sharp Bowyer give the average load per Lanc sortie as 3.9 tons (don't ask me if long or short).

In September '43, the Air Ministry did a calculation of economic efficiency of Mossies vs. Lancs. The data they had for average Lanc load for June and July '43 was 7,450 lbs.

So, about 2 Mossies per Lanc, in terms of absolute load actually carried, assuming Mk.XVI and cookie, of course.

I suppose I'll allow myself a little thread creep, as economics has been referred to above.

AVIA 46/116
Mossie: 92 sorties per write-off
Lanc: 28 sorties per write-off

Average Cookie Mossie load: 4,000 lb
Average Lanc load June July 1943: 7,450 lb (don't ask me, I'm only the messenger)

Therefore:

Moss/Lanc relative effectiveness =

(92 sorties * 4,000 lb / 30,000 man hours)
__________________________________

(28 sorties * 7,450 lb / 84,000 man hours)

= 12.25 lbs bombs dropped per man hour / 2.48 lbs dropped per man hour

= 4.95 Coste effectiveness (i.e. Mossie is 4.95 times as cost effective as the Lanc)

It also notes that the "life load" of one Lanc, given the above life expectancies and weights carried, is less than 60% of that of the Mossie (while costing 3 times as much labour and using twice as many Merlins). It also notes, to use their term, that "crew wastage" in the Lanc is 4 (sic) times higher.

As a reference, here's a graph of Bomber Command loss rates (month-by-month and cumulative) excluding the Mosquito force (LNSF), versus the loss rates (again, month-by-month and cumulative) for the Mosquito force.

Bear in mind there was a large drop in the cumulative loss rate towards the end of the war as the number of BC sorties jumped, thus:

Hope not too much thread creep.

 

[mhuxt]

Hi Vincenzo,

Sharp Bowyer's "Mosquito" primarily, they provide a table with all Mosquito sorties to Berlin, month-by-month January to May '45, with one column listing the number of cookied dropped, again by month, 1,459 in total. Also checked Barry Blunt's "571 Mosquito Squadron" as a double-check on the "two-in-a-night" claim to back up another table in Sharp Bowyer.

 

[Matt308]

I'm a fan of the unarmed bomber, so ditch the gun weaponry (and the men manning it, and the life support for those, along with armor protecting them), so you can be reasonably fast.

You mean like the Japanese.

 

[Vincenzo]

Hi Vincenzo,

Sharp Bowyer's "Mosquito" primarily, they provide a table with all Mosquito sorties to Berlin, month-by-month January to May '45, with one column listing the number of cookied dropped, again by month, 1,459 in total. Also checked Barry Blunt's "571 Mosquito Squadron" as a double-check on the "two-in-a-night" claim to back up another table in Sharp Bowyer.

if the average load is 1.09 it's so strange that so long mission had a larger load, but if was so was so. Probably so late in war they were used more near to the limit

on your comparison you can't compare lancaser average in summer '43 with a choice load (max) of Mosquito, also in the '45 raid over Berlin the average for the Mosquito is 1.15 ton

 

[wuzak]

if the average load is 1.09 it's so strange that so long mission had a larger load, but if was so was so. Probably so late in war they were used more near to the limit

on your comparison you can't compare lancaser average in summer '43 with a choice load (max) of Mosquito, also in the '45 raid over Berlin the average for the Mosquito is 1.15 ton

Many Mossies still in service were B.IV/B.XX types, and most of them weren't converted to carry the 4000lb bombs, so they were stuck with 2000lb internal (ie 1 short ton).

Many Mossies were involved in pathfinding and marking operations, which required the use of target indicators, which could be 500lb or 1000lb bombs - again a maximum of 2000lb. This all serves to bring the average down.

 

[Aozora]

First Mosquito raid carrying 4,000 lb bombs was against Dusseldorf on 23/24 February 1944, 627 Sqn. First attack on Berlin 13-14 April 1944 by eight Mosquito XVIs of 692 Sqn., each also equipped with 2 x 50 gal drop tanks. By the end of April 692 Sqn had flown 200 sorties, dropped nearly 200 4,000 pounders with no losses. Between 15 July to 15 August '44 Mosquitos dropped 336 4,000 pounders on Berlin. (Sharp and Bowyer pages 308-312).

 

[Vincenzo]

just need to know if pathfinding missions are counted as bombing mission
the Mosquito has the higher miscellaneous operations in the count , for the mosquito 39% of bombing mission, for the lancaster only the 3%

 

[parsifal]

mhust what is the source of Mosquito with 4,000 lbs on Berlin?

parsifal Stirling is a older plane.
Lancaster was the newest 4 engined (and however go in mission before of Mosquito bomber), and the mosquito has not twice the speed (probably 200 vs 245 in most economical and 250 vs 320 in max weak)

Half right. Stirling first flew May 1939, entered squadron service end of 1940, was the main heavy type 1941-3, started to fade from the latter part of 1943.

De Havilland Mosquito was conceived in 1938, and could have had its first flight in 1939, that is, at the same time as the Stirling. RAF scepticism delayed the Mossies first flight until 1940. First flight was in early 1940, less than a year after the Stirling, and squadron service was from July 1941, again within a year of the Stirling.

However, Mosquitoes could easily have entered service before the Stirling, in fact have been in quantity use even before the Heavy was ready for entry to service. The basic idea behind the Mosquito was something the company had been working on since 1936.

Your figures for ecomic cruising speed are differnt to what i understand. the type could "cruise to Berlin and back at just over 300 mph (in fact at 320mph) carrying a 1500 lb bombload. Your figures I think (but I havent checked) appear to relate to a Mosquito in an overladen condition, ie carrying a 4000 lb bomb at maximum range, which is somewhere beyond Berlin.

 

[nuuumannn]

The key to a successful bombing campaign is the destruction of the intended target, or the neutralisation of a force brought about by the destruction of key targets. Bearing this in mind, a fleet of 100 Mosquitoes can be as effective at doing so as a fleet of 100 Avro Lancasters.

The determining factor is accuracy of the delivery of the bomb load, not necessarily the size of it. A Mosquito could be as accurate a bomber as a Lancaster and had a higher probability of getting home safely.

The reason why the RAF developed its area bombing policy was because of a lack of accuracy in finding and destroying its targets. During the Blitz, the Luftwaffe had the means to deliver a specific bomb load onto a precise target, but did not successfully pursue this course of action as effectively as it could have. The bombing and subsequent disruption of production at the Hillington Rolls Royce plant at Glasgow proved to be of greater strategic value to the Germans than the bombing of Coventry. They had the means of really disrupting British military production, but did not act on it as effectively as they could have, not to forget the effectiveness of British countermeasures to their radio guidance systems, which gave them their potentially formidable accuracy. The heaviest internal bomb load carried by any of its bombers was around 1,000 kg aboard the He 111.

By 1943 - '44 a lot had changed in the size of load available and the accuracy at placing the load, but the objective was the same. In hindsight, area bombing of cities proved ineffective at bringing a civilian population to suing for peace, although the destruction of Hamburg and other German centres through this policy no doubt provided a certain hindrance to Germany's war plans. Nevertheless, the devastation of factories, ports, transport infrastructure etc was what was going to bring about a quicker end to a bombing campaign than devastating cities in the hope that railways and a few factories will get burned out.

Bearing this in mind, accuracy of the placement of a particular bombload is of supreme importance. This could be achieved with advanced radio navigation aids and an effective bomb sight. The qualities inherent in a particular aircraft design that gives it better survivability are a distinct advantage; being able to reach the target and successfully return to be able to be used again without being lost in barely sustaineable numbers due to enemy defences. Yes, the size of bomb load is important, but if the target can be neutralised using smaller, more survivable aircraft than larger types, then why waste resources?

 

[nuuumannn]

Add to this effective post raid reconnaissance so you can see how accurate your previous night's work was. You can even use the same airframe as your bomber force, if you like.

 

[parsifal]

I just dont get these aleged performance figures. I just went to the RAE Test results to check

Mosquito Performance Trials

and it says that the max continuous cruise speed for a BIV carrying 2000 lb bombload was 330 mph.

RAAF testing of its PRU (no bombs, but PR gear and max fuel) Mk 40s flying from Northern Australia to the Northern coast of Borneo (a bloody long way) was 270 mph.

Im not sure where these figures of 250 mph max sustained cruise speeds are coming from, but they are not the figures Ive ever seen.

In any event, if you want to believe or claim the Mossies was only as fast as a Lanc, or just slightly better, go ahead, knock yourself out. Bottom line is this, LW fighters found the Mossie to be so fast, even under fully loaded conditions, that they could not catch them. It was one of the main reasons why Mossie loss rates were so low, and why the Mossie could udertake significant high risk deep penetration raids day or night into occupied Europe and Germany.

 

[mhuxt]

Mosquito average bomb load in bombing 1.08



source lancaster-archive.com, calculations mine

That source includes 100 Group (Bomber Support, basically long-range night-fighting and intruder sorties, at both high and low level) in the total for Mosquitos. Bombing sorties should be 27,069 for ops in 8 Group, another 266 for night ops up to April '43, and 727 (IIRC) for daylight bomber ops in 2 Group. Those 11,046 "Miscellaneous Ops" are 100 Group. I believe the total of 28.639 at that site will include weather sorties by 1409 Flight, 1,364 in total according to my info.

Strikes me as perfectly legitimate to compare a cookie Mossie with most recent Lanc stats, as the goal was to decide how to build a strategic bomber force, making best use of crew, material and time. Good argument for getting away from the heavies, but for my money BC was committed by that point.

 

[stona]

With WWII era bomb sights high operating altitude almost guarantees poor accuracy. If you aren't going to hit the target then why bomb at all?

But you could hit a target. You just needed hundreds of bombers dropping a lot of ordnance to have a good statistical chance of doing so. That's why it was done that way.

If they'd had a system capable of dropping a bomb down a chimney stack like today then that's how it would have been done,but they didn't.

Cheers
Steve

 

[stona]

Mosquitoes were the designated precision bombing aircraft and selected as Pathfinders for the bombing force for a reason.

The Mosquito wasn't the designated precision bombing aircraft. Most precision bombing was done by Lancasters with the more accurate SABS dropping ordnance that the Mosquito couldn't lift.
9 and 617 squadrons were designated precision bombing units within mainforce,both flying Lancasters.
The Mosquitos carried out the famous special low level raids with mixed results.

It took until August 1942 for Harris to be allowed to found the Pathfinder Force. The last hurdle to be cleared was finance. Harris wanted Pathfinder crews to be promoted one rank to compensate for the danger inherent in a longer tour and this cost money which the Treasury,as ever,was unwilling to part with.

Initially the Force operated four types,Lancasters,Halifaxes,Stirlings and Wellingtons.In the same month (August) 109 squadron became the first experimental "Oboe" unit,flying Wellingtons.

The first target marking bombs became available in January 1943,the same month that the Pathfinders were given Group status,becoming 8 Group.

It is a common misconception that the Mosquito was the Pathfinder aircraft. 8 Group's Wellingtons (305 sorties) Stirlings (826 sorties) and even Halifaxes (2,106 sorties) were abandoned fairly soon but they flew 19,601 Lancaster sorties. In total the Group flew 22,838 sorties with their "heavies" with a loss rate of 2.5%. That compares with 28,215 sorties with Mosquitos with a loss rate of 0.4%. Not all those Mosquito flights were target marking. The operations of 1409 (meteorological) flight which was part of 8 Group,are included in the total.

Cheers

Steve

 

[parsifal]

thanks steve, Ive learnt something

 

[Aozora]

Bombers carrying large bomb loads are an inevitable result of the relative innaccuracy of bombing in WW2. In simple terms you needed a lot of bombers dropping a lot of bombs to effectively hit your target.
Even RAF raids carried out with the benefit of electronic aids,pathfinders,master bombers etc in late 1943 and later demonstrate this. Peenemunde springs to mind.

Using the RAF's standard Mk XIV bombsight in tests in March 1945, 9 Sqn ,bombing in daylight from 20,000ft achieved an average error of 195 yards. Using the more accurate but rare (about 1,000 manufactured) SABS MkllA bombsight, 617 Sqn achieved an average error of 125 yards at the same time. This was a specialist precision bombing unit,using the SABS operationally to drop special ordnance like Grand Slam and Tallboy.
The USAAF using their Norden sight rarely achieved even 9 Sqn's accuracy. Only 31% of american bombs landed within 1000 ft (call it 330 yards) of the target.

To be statistically certain of destroying a typical industrial building 200' x 200' you have to drop hundreds of bombs.

In an ideal world a fast,unarmed bomber carrying a lighter load (like the Mosquito) might seem the solution but an ideal world it was not.

Cheers

Steve

For interest, here are the Mk XIV and SABS:

(From Dambusters Owner's Workshop Manual, Ian R Murray, Haynes 2011).
It could have been a very different strategic bombing campaign had the British adopted - or been able to adopt - Barnes Wallis' concepts for streamlined "earthquake" bombs (Tallboy and Grand Slam) early in the war, plus the high altitude, high speed bombers capable of carrying them, along with the precision sights such as Mk XIV and SABS. Again, it was not an ideal world.

 

[Glider]

The Mosquito wasn't the designated precision bombing aircraft. Most precision bombing was done by Lancasters with the more accurate SABS dropping ordnance that the Mosquito couldn't lift.

I think it would be fairer to say that the Mosquito and the Lancaster were the designated precision bombers. The difference was of course the payload and the ability to survive.

With the huge cost and effort that went into building the abnormal Tallboy and Grandslam bombs and specialised aircraft to carry them it is obvious that special crews were needed.

As for the normal pathfinder missions is it true to say that both Mosquito's and Lancaster bore the brunt in the last 12/18 months of the war. Mosquitos were also used for the spoof raids and small nuicence raids designed to basically keep the germans awake. Without the protection of the 'herd' or main force Lancasters would have been too slow and vulnerable in this role.

If sufficient Mosquito's had been available would they have replaced the Lancaster in the Pathfinder role, frankly who knows. Its a guess and only a guess but I think they probably would. If only for two reasons:-
a) the pathfinder units were manned by the best and most experienced crews in the RAF and it would make sense to give them the maximum chance of survival
b) it would release Lancasters for the main force where the weight of bambs carried would be so important.

 

[Vincenzo]

Parsifal: Stirling first flight May '39, Mosquito first flight November '40. My cruise figure were from RAF data card of B XVI of 1.5.44 and max weak figure was 311 mph not 320 mpg (is 321 in backward), that of Lancaster were my estimation from Manchester data card. The range of B.XVI with 2,000 lbs at max weak is 1165 miles, so i don't think that Berlin it's in the range at max weak, calculating reserve and that the route in not a straight line (obviously w/o drop tank)

Wuzak: however Lancaster can fly over Berlin with 14,000 lbs so in a logical comparation you need compare Mosquito with 4,000 to Lancaster with 14,000 or you can comapre actual average laod with actual average load. Imho the pathfinding mission was counted in miscellaneus operations

 

[mhuxt]

I'm going to need some convincing that the Lanc went to Berlin with 14k. The ORB pages that I'm looking at over at the 156squadron.com site show 10k, journey took 7 hours. The Mossie logs I've seen say 4 1/4 - 4 1/2 for Berlin.

I suppose you can believe anything you want about the miscellaneous ops, but I'm telling you, the ops for the bomber units are laid out squadron by squadron, month by month in Sharp Bowyer's book.

Oh, and an XVI with 2k isn't going to have wing bombs, it will either have "clean" wings or drop tanks, which took about 6 mph off total speed, less than the bombs and their accompanying gear.

Beyond that, I can really no longer be bothered, especially as it's now well off topic.

 

[tomo pauk]

You mean like the Japanese.

No, Japanese bombers (at least vast majority of them) were featuring defensive guns gunners.