Max bomb loads to distances for BC 4 engine bombers

[mongoose44]

I assume the fuel allowance included the indirect approach as that was calculated in the total mileage. As for the climb, one would imagine that was somewhat (altho' being empty on the way back, not completely) compensated by the descent needing less + the return trip probably using less. Ground speed v.v. air speed might effect it though. The 200 gal was a reserve?

Is there similar data for either the Merlin or PW engined Halis?

[Graham Boak]

Bristol-engined Halis, not P&W. I have some but it may take some digging out. Is your consumption figure at full load or empty? I have done this sort of thing professionally (although not on Halifaxes and Lancasters!) and simplified assumptions can lead to misleading results.

The back of the Air Britain Hampden and Stirling Files do give range with different payloads, in what looks like an official format. I'll try to check over the weekend if the equivalent data is in the Lanc and Hali Files.

[Kutscha]

Graham do you have 'range to load' charts for the B-17, B-24 and Mosquito?

Not theoretical but for operational missions.

[mongoose44]

Originally Posted by Graham Boak

Bristol-engined Halis, not P&W. I have some but it may take some digging out. Is your consumption figure at full load or empty? I have done this sort of thing professionally (although not on Halifaxes and Lancasters!) and simplified assumptions can lead to misleading results.

The back of the Air Britain Hampden and Stirling Files do give range with different payloads, in what looks like an official format. I'll try to check over the weekend if the equivalent data is in the Lanc and Hali Files.

I need to work out fuel and bomb loads for different distances. I assume the bomb load would depend on the fuel needed for that distances as per the Lanc above.

BTW many thanks.

[Graham Boak]

Merrick's Halifax book quotes ranges for different bombloads, and hence fuel loads, for each of the Halifax variants. There is something odd about the Mk.II values, in that the Series 1a is given significantly shorter ranges than the series 1, despite the former's much higher drag.

However, for the Mk.1
13000lb bombs, 955gals fuel, 220 retained as allowance, 1000mile range
8500lbs, 1552 gals (160gal Hampden tanks in fuselage). 1740 miles
7750lbs, 1640 gals (tanks in wing bomb cells), 1840 miles
1300lbs, 2330 gals (all auxiliary tanks), 2720 miles

Mk.II Series 1
13000lb, 985 gals, 210 allowance, 920 miles
6500lb, 1886 gals, 1900miles
-, 2576 gals, 2,650 miles

Mk.II Series 1a
13000lb, 830gals, 290 allowance, 650 miles
5250lb, 1882 gals, 1660 miles
1500lb, 2342gals, 2,100 miles
-, 2,572 gals (3 auxiliary tanks), 2320 miles

Mk.III wartime
13000lb, 1020gal, 220 allowance, 930 miles
7250lb, 1802gal, 1770 miles
-, 2492gal, 2430 miles

Mk.VI wartime
13000lb, 1090gal, 320 allowance, 970 miles
6300lb, 1982gals, 1965 miles
2500lb, 2442gal, 2490 miles
500lb, 2672gals, 2745 miles

Postwar saw the aircraft cleared to an additional 5t max. t/o weight, with considerable improvements in range.

For the Mk.II, optimum cruise outbound at 15000ft was 160(170) mph giving just less than 1.05 airmiles per gallon. I don't know why the two speeds are quoted, unless the faster speed applied to the Merlin 22 (Series 1a), in which case the am/g should improve too. Optimum cruise homeward at 15000ft was 1.21 am/g at 150(160) mph.

Climb to 15000 ft used 125 galls over 46 miles in rich mixture, or 180 galls over 115 miles in weak mixtures. Numbers estimated from coarse graph.

Similar information is available for the Stirling in Air Britain's The Stirling File, similarly for the Hampden, but I have not traced anything as detailed for the Lancaster or Wellington. But I don't have a lot on the Wellington, and have yet to browse Lancaster books other then the Air Britain File, which wasn't helpful.

Edited to correct Imperial measures (damn them!) Plus typing errors in edit.

PS Operating radius will be about one third the range.

[mongoose44]

Thanks Graham. Very useful. I looked at the Air Britain page; $60 is alot per book! (seeing as I am in America and can't get them from a library no doubt!)

If you have the Stirling info that would be useful.

[Graham Boak]

From The Stirling File

Mk.I Hercules Mk.II
64,000lb MTOW, 3500lb bombs, 2000miles

Mk.I Hercules Mk.VI
70,000lb MTOW,
14000lb bombs, 740 miles
5000lb, 1930 miles
1500lb, 2330 miles

Mk.III
70,000lb MTOW
14000lb, 490 miles
3575lb, 2010 miles
nil, 2440 miles

Please note and forgive corrections to previous posting.

[Jim Oxley]

Just a question on the range (miles) figures quoted.

Naturally they have to be halved for determining radius of action. But what is the fudge factor (which will limit even further the distance that can safely travelled) in-built?

For example for fighters several figures are often shown for range. One is max range ie at best cruise speed with drop tanks, second is normal range ie clean at cruise speed, and then there is operational range ie full war load with 15% fuel retained for emergencies eg combat. Naturally operational range is the smallest radius quoted.

Are the figures above the same as a fighters 'operational' range?

[Graham Boak]

The above figures are for optimum range with the allowance quoted for each Halifax variant - there is no specific statement about reserves for the Stirling. 10% of normal would be a reasonable guide for touchdown at home base - 225gals for the Stirling. I doubt that they have any combat allowance.

Combat radius can generally be taken as being one third of the optimum range, which allows for routing, combat, and perhaps any additional diversion. I know of no source which quotes allowances for such operational details - the routing would be dependent upon target and known enemy defences deployments, plus whatever routing was desired on the Allied side to clear space for night fighter operations, Allied AA, balloon barrages etc. All these factors would vary throughout the war.

A sensible commander would then allow another factor for not all crews being able to obtain optimum performance from their aircraft, either through lack of skill or worn aircraft - or indeed unexpected headwinds in the mission. The sum of these factors might be so limiting that a high-ranking commander may have to decide whether this or that target was so important that risks should be taken, and the factors reduced.

Perhaps a study of individual raids would give an understanding of the level of such diversions. Compare the actual routes flown with the direct distance.

[Nick Beale]

Originally Posted by paul peters

Berlin is 1836 miles

From where? From Bomber Command's bases in eastern England it is more like 550 miles each way (on a straight line). You would have to take a lot of diversionary legs to get to your figure.