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Historical bombing altitudes were ~32000ft and 29000 ft (Nagasaki)
Lancaster VI service ceiling is 28500ft at 65000lb TO weight. However, at weapon release, the aircraft will have burnt off about 1500-1800 IG of fuel (~11000 to ~13000lb from 72000lb TO weight) and weight will be 61000-59000lb with a consequent increase in service ceiling. However even at 28000ft a Lancaster would have been safe from the ~21kt yield of a FAT MAN bomb as was proved by Bockscar dropping at ~29000ft. The LITTLE BOY bomb only had a yield of 13kt.
he above states .95 AMPG at mean mission weight of 66500lb = 2850 miles with 3000IG of fuel.
Don't know if this will help any:
This all simply boils down to whether the Lancaster, with reasonable modifications, could act as a 1945 nuclear bomber. Not what would be the best nor issues of nationality nor if it were actually considered for it.
i think that's slightly optimistic.
I calculate a reduction in air density of 17% (ie 83%) between 23500ft and 28000ft which would reduce lift by 17%. In addition as the engines are above FTH the power would also drop 17%. A 12000lb reduction in weight from 72000lb to 60000lb is also a reduction of 17% however the reduction you refer to is from 65000lbs to 59000lbs is only 10%. There is a slightly reduction in parasitic drag. Although I can't see the operational ceiling (500 fpm) going from 23500 to 28000ft I can see it going to half way there, maybe 26000ft but the aircraft would reach 28000ft with maybe a climb rate of only 200fpm. This means the aircraft is hanging on the very edge edge of a stall with the engines at maximum power. This is a problem for an aircraft whose main escape was a corkscrew that generally lost enemy night fighters, The "silver plate" Lancaster VI would no doubt have fishpond for its H2S radar and village inn radar for its tail gunner and have the dorsal turret deleted. I think the Lancaster could drop little boy. Incidently the first atomic bomb to go off was little boy over hiroshima. There was no prototype test so yield could have been higher. Nitrous Oxide was used on single stage Merlin Mosquitos and we know the two stage used them so a nitrous oxide supply was a possibility. I think 26000ft is a good enough altitude and if done at night stood good chances of evading interception.
Air Pressure at Altitude Calculator
(assuming boyles law on PV = constant
And if you increase the fuel load you have to decrease the warload, which pushes it below the value of even the Little Boy bomb. Trials carried out with the Lancaster fitted with overload saddle tanks showed that with a max take off weight of 72,000lb calculated from a standard 2,154gal internal fuel load, plus the saddle tank fuel load the radius of action was 1,500 miles with a 6,000lb load.
With the saddle tank, the maximum range was 3,154 miles, but again the warload was 6,000lbs.
(1)Range or load? Can't have both.
(2)Nice drawing, but it only shows the diameter of the bomb body, not the fins, which equates to a box of the same diameter as the body, of 1.5m each flat side. That cannot be carried internally - the width of the bomb is wider than the internal bomb bay walls. It would have to be suspended below the fuselage level. Let's also consider for a minute what impact that will have on drag.
(3)Correct, but nationality was on the cards, both Groves and Arnold wanted an American bomber.
Max TOW of the Lancaster was increased to 72000lb, which along with the more compact and balanced Atomic bombs would have allowed for additional fuel via internal aux bomb bay tanks. So a Lancaster could carry ~3000IG of internal fuel and a ~10000lb Little Boy or Fat Man bomb.
Again, Okinawa cannot be used as an Atomic staging base.
It was under constant attack by the Japanese and would put the atom bomb program in jeopardy.
Aside from the fact that there was a limited supply of atom bombs, if one of the bombs was destroyed by a Japanese bomb, there would be the issue of radioactive debris.
Again though, this is entirely fictional. If you add extra tanks in the bomb bay plus max internal fuel load and warload, you have exceeded your maximum take off weight. And again, can't carry Fat Man at all.
Okinawa was used to stage Bockscar to Tinian after the Nagasaki mission.
Stage? Visit? Irrelevant!!! The fact is the mission STARTED from Tinian!!!!
Yes, as I previously stated, Bockscar's actual Nagasaki mission staging = Tinian->Nagasaki->Okinawa->Tinian. This would be the staging plan for a Lancaster mission.
2) Again Fat Man width was 60.25in or less while the Lancaster B-B was 61in wide by 38in deep. So some protrusion, similar to the existing radome. This is assuming that no mods can be made to the ceiling of the bomb bay.
The ceiling of the bomb bay was the centre wing section.
I can't find the dimensions of the H2S radome at this time. However, I doubt it sat as low as the Fat Man bomb would.
As nuuumannn said:, the box tail of the Fat Man bomb was as wide as the bomb diameter - 60in. Which means that the biggest part of the bomb within the actual bomb bay was 60" wide, leaving only 1" extra room, or 0.5" per side. Doesn't seem practical, especially if you want to use some sort of bomb door.
It's also worth mentioning that at a max take off weight of 72,000lbs the Lancaster was a beast to fly. The A & AEE recommended that only the most skilled pilots fly it, the engine oil temps were at their maximum safe level at less than max rate climb and any speed over 260mph provoked severe vibration throughout the airframe. Cruise was restricted to below 170 to 180mph. Flying at that speed over Japan in 1945?
It's worth remembering that the Lancaster VI suffered vibration and overheating during A&AEE trials resulting in the loss of an airframe during testing, with thankfully no loss of life. Performance figures were an improvement, but the decision was made to not pursue the type, and as posted previously, it was withdrawn from service in November 1944.
Regarding in-flight-refuelling, Lancasters were used in trials in late 1944 and these were promising, but no in service examples were so fitted by August 1945.
Typical teething issues but we then have a Lancaster VI achieving Mach .72 at 25000 ft and no engine problems in June 1944.
The ceiling of the bomb bay was the centre wing section.
I can't find the dimensions of the H2S radome at this time. However, I doubt it sat as low as the Fat Man bomb would.
As nuuumannn said:, the box tail of the Fat Man bomb was as wide as the bomb diameter - 60in. Which means that the biggest part of the bomb within the actual bomb bay was 60" wide, leaving only 1" extra room, or 0.5" per side. Doesn't seem practical, especially if you want to use some sort of bomb door.
Roy Chadwick said it was practical.
Fat Man would protrude about 22-24in. The Radome extends about 1/4 of the height of the max aircraft fuselage height so they seem quite comparable
Roy Chadwick said it was practical.