Range drop tanks and declining returns

slaterat said:

Just thought I would post this info on hurricane 2 range. Notice how the increase from 45 to 90 gallon tanks doesn't get a large increase in range the increased weight and drag seems to use up most of the extra fuel capacity.

Also notice how much fuel is used at higher boost rates. At 9 lbs boost fuel consumption is 100 gal per hr. That's about 16 gallons for 10 minutes of combat!

I suppose the hurricanes effective combat range while carrying the two 45 gal tanks would be a bit over 400 miles?

Slaterat

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An uncontrolled landing Whitley destroyed Z2905 on
8 June 1942 after only a few but busy weeks at A& AEE,
starting with trials of two 44 gal drop tanks and then two
larger (90 gal) tanks. The latter gave a total capacity of
274 gal and all up weight of 9130 lb. Even the smaller
tanks enabled a 5 hr 45 min endurance flight to be flown,
and the larger tanks gave a maximum range of 1,500 miles
provided the tanks were jettisoned when empty. Handling
after take-off (taking a run of 348 yd from a concrete
runway) was unpleasant due to instability, and the pilot
was unable to see the tanks.

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Admiral Beez said:

I often wondered why external tanks weren't considered for the Doolittle Raid. Or any multiple engine bombers for that matter.

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Shortround6 said:

Most of the time bombers were weight limited, not volume limited.
They could find more space for fuel than they could get off the ground without very long airstrips.

Drop tanks did show up on the Mosquito, the B-26 and the Lockheed Ventura. maybe a few others during the war.

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Greg Boeser said:

The B-26 Marauder did not carry drop tanks. It could be fitted with auxiliary tanks in the bomb bay(s).
B-25s maybe?
I know that the PV-1s flying out of the Aleutians were fitted with drop tanks. They learned that flying at higher cruise settings actually improved range.
I have seen pilot manuals that have different settings for max endurance and max range.

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Admiral Beez said:

I often wondered why external tanks weren't considered for the Doolittle Raid. Or any multiple engine bombers for that matter. I suppose gas is weight that would otherwise be bombs.

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Simon Thomas said:

found this paper to be a rather amusing way to extend range.

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Admiral Beez said:

I often wondered why external tanks weren't considered for the Doolittle Raid. Or any multiple engine bombers for that matter. I suppose gas is weight that would otherwise be bombs.

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Certain modifications had to be made to the B-25Bs to make them suitable for the mission. Since the raid was going to be made at low level, the retractable ventral turret was removed, saving about 600 pounds of weight. More fuel was added to the plane, bringing the total fuel load to 1141 gallons--646 gallons in the wing tanks, 225 gallons in the bomb bay tank, 160 gallons in a collapsable tank carried in the crawlspace above the bomb bay, 160 gallons in the ventral turret space, and ten 5-gallon cans for refills. The still-secret Norden bombsight was removed, lest it fall into Japanese hands. It was replaced by a makeshift bombsight that proved more satisfactory for low level operations. The bomb load consisted of four 500-pound bombs. As a deterrent against Japanese fighters making stern attacks, a pair of dummy guns in the form of wooden sticks painted black were attached to the extreme rear fuselage, protruding out the back of the transparent tail cap. Takeoff weight was about 31,000 pounds.

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Weights: 20,000 pounds empty, 28,460 pounds loaded, 31,000 pounds maximum.

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Admiral Beez said:

I often wondered why external tanks weren't considered for the Doolittle Raid. Or any multiple engine bombers for that matter. I suppose gas is weight that would otherwise be bombs.

Click to expand...