Again, the max width of Fat Man is 60.25in so it will fit. The minimum width of any design was 59in.
The Lancaster as a potential nuclear bomber in 1945
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Again, the max width of Fat Man is 60.25in so it will fit. The minimum width of any design was 59in.
FLYBOYJ
"THE GREAT GAZOO"
It could fit but can it be safely deployed???
Again, Chadwick assured Ramsey (who concurred) that it could be safely deployed. I have to admit that I'm not knowledgeable enough about the Lancaster to contradict it's designer...
FLYBOYJ
"THE GREAT GAZOO"
Well I helped load bombs in aircraft that had a bomb bay. I would not want to be on any aircraft that had live ordinance hung with a 1/2 inch clearance between the weapon and structure. I'd contradict Chadwick, Kelly Johnson or Wilbur Wright!
A destoyed atomic bomb of the little man U235 gun type weapon would produced an insignificant amount of radiation since U235 is not particularly radioactive. Dispersed plutonium 239 from a fat man is probably a more serious matter. The fissile material is inside and extremely strong case.
ThomasP
Senior Master Sergeant
Hey guys,
I realize that you may have seen the actual blueprints already, but here are some of the basic dimensions of the Mk III 'Fat Man' bomb type (as deployed) from an ordnance manual.
Maximum length of bomb including fins: 128.625"
Maximum diameter of bomb casing: 60.25"
Maximum width across flat of bomb fins: 59.00"
Note: I converted fractional dimensions/tolerances to decimal.
Looking at the tail design I can not see any reason why it could not have been modified to one degree or another while still maintaining the required aerodynamics, possibly including a high drag device of one type or another. I do not think that the original tail dimensions should be used to determine if the 'Fat Man' could be carried by the Lancaster.
As far as the casing diameter is concerned, a guppy bulge bomb bay modification should satisfy the clearance problem. A new section profile could be built up easily enough, and there is no reason that 'enough' clearance could not be incorporated (I think). The effect of such a bulge may (will?) cause increased drag, but I have no way to really estimate the new CD. Would the drag increase be enough to prevent the modified Lancaster from meeting the range requirement? However, I do not think the Lancaster flies fast enough that area rule need be applied.
I realize that you may have seen the actual blueprints already, but here are some of the basic dimensions of the Mk III 'Fat Man' bomb type (as deployed) from an ordnance manual.
Maximum length of bomb including fins: 128.625"
Maximum diameter of bomb casing: 60.25"
Maximum width across flat of bomb fins: 59.00"
Note: I converted fractional dimensions/tolerances to decimal.
Looking at the tail design I can not see any reason why it could not have been modified to one degree or another while still maintaining the required aerodynamics, possibly including a high drag device of one type or another. I do not think that the original tail dimensions should be used to determine if the 'Fat Man' could be carried by the Lancaster.
As far as the casing diameter is concerned, a guppy bulge bomb bay modification should satisfy the clearance problem. A new section profile could be built up easily enough, and there is no reason that 'enough' clearance could not be incorporated (I think). The effect of such a bulge may (will?) cause increased drag, but I have no way to really estimate the new CD. Would the drag increase be enough to prevent the modified Lancaster from meeting the range requirement? However, I do not think the Lancaster flies fast enough that area rule need be applied.
FLYBOYJ
"THE GREAT GAZOO"
So with all this said, could the Lancaster been used as a nuclear bomber? - IMO yes. But based on what's been shown, the mission, deployment and possible modification would have been "shade tree" at best.
Yes, the Lancaster was "considered" for use, this has been well documented. It was also well documented that Generals Groves and Arnold dismissed this possibility from ever happening.
End of story.
So what did we get by this decision:
The Siliverplate modification not only enabled the B-29 to carry either bomb, but it turned out to be a well engineered solution that not only provided a superior delivery platform than any Lancaster or Lincoln mark, but was used after the war to provide the US with it's first nuclear delivery fleet. Any Lancaster mod "would have" been a one trick pony, hastily done with huge risks IMO. (Single piloted muti-engine taildragger for starters)
The Silverplate mod was a 6000 man-hour modification that reconfigured interior bulkheads and installed a 33 foot bomb bay. The "weaponeer" position was created, Curtiss Electric Propellers and bomb bay cameras were some of the other airframe mods. Silverplate B-29s were 6000 pounds lighter and also had R-3350-41s in lieu of the -23s that were initially installed on production B-29s, giving a combined 800 additional HP. I read somewhere that Bockscar reached 365 MPH and had a service ceiling of over 31,000 feet. As mentioned, this modification enabled both bomb configurations to be supported and hosted other mods that made these aircraft a true nuclear delivery system. No bulging bomb bays, no bulging bomb bay doors, the payloads fit INSIDE the aircraft with ample room.
So at the end of the day, this modification provided a custom built delivery system that resulted in 65 of these aircraft being produced, either through field modification or delivered off the production line (The Martin-Omaha facility produced 57 of these aircraft). Silverplate B-29s remained in service after the war and were finally taken out of service in 1951.
Despite the "consideration" to use the Lancaster as the first nuclear bomber and despite the performance "wish list" and hypothetical mission calculations pushed by RCAFson, I am not aware of anyone (USAAF, Bomber Command) putting any real thought or effort in converting any Lancaster or Lincoln into operational nuclear bombers in the post war years (although I believe a Lincoln was used in the tests of the UK's first atomic bomb) unless we want to consider those "Black Lancasters."
The Silverplate B-29s "would have" out performed and out delivered any Lancaster modification and this is based on what was shown here.
Yes, the Lancaster was "considered" for use, this has been well documented. It was also well documented that Generals Groves and Arnold dismissed this possibility from ever happening.
End of story.
So what did we get by this decision:
The Siliverplate modification not only enabled the B-29 to carry either bomb, but it turned out to be a well engineered solution that not only provided a superior delivery platform than any Lancaster or Lincoln mark, but was used after the war to provide the US with it's first nuclear delivery fleet. Any Lancaster mod "would have" been a one trick pony, hastily done with huge risks IMO. (Single piloted muti-engine taildragger for starters)
The Silverplate mod was a 6000 man-hour modification that reconfigured interior bulkheads and installed a 33 foot bomb bay. The "weaponeer" position was created, Curtiss Electric Propellers and bomb bay cameras were some of the other airframe mods. Silverplate B-29s were 6000 pounds lighter and also had R-3350-41s in lieu of the -23s that were initially installed on production B-29s, giving a combined 800 additional HP. I read somewhere that Bockscar reached 365 MPH and had a service ceiling of over 31,000 feet. As mentioned, this modification enabled both bomb configurations to be supported and hosted other mods that made these aircraft a true nuclear delivery system. No bulging bomb bays, no bulging bomb bay doors, the payloads fit INSIDE the aircraft with ample room.
So at the end of the day, this modification provided a custom built delivery system that resulted in 65 of these aircraft being produced, either through field modification or delivered off the production line (The Martin-Omaha facility produced 57 of these aircraft). Silverplate B-29s remained in service after the war and were finally taken out of service in 1951.
Despite the "consideration" to use the Lancaster as the first nuclear bomber and despite the performance "wish list" and hypothetical mission calculations pushed by RCAFson, I am not aware of anyone (USAAF, Bomber Command) putting any real thought or effort in converting any Lancaster or Lincoln into operational nuclear bombers in the post war years (although I believe a Lincoln was used in the tests of the UK's first atomic bomb) unless we want to consider those "Black Lancasters."
The Silverplate B-29s "would have" out performed and out delivered any Lancaster modification and this is based on what was shown here.
GrauGeist
Generalfeldmarschall zur Luftschiff Abteilung
I was thinking about Sweeney's mission and led me to wonder.
Suppose Bockscar was one of these unicorn Lancasters - would it have been able to follow the exact timeline of eventsbas the actual B-29 or would it have been lost in action?
I've seen a great deal of effort to try and "fit" a Pumpkin Bomb into it's bomb bay, so let's assume the fuselage was widened enough to safely accommodate it's dimensions.
Would it have had enough fuel to not only made the trip from Tinian to the rendezvous point, then on to the primary and secondary target then on to Iwo Jima (Okinawa only in an emergency)? For the record, the Silverplate B-29s had a capacity of 7,250 gallons of fuel.
And what about both the imposed drag penalty of the bulging fuselage as well as additional fuel burn for extended (unscheduled) loiter time?
Nearly an hour was spent trying to find a bombing solution for Kokura before moving on to Nagasaki. Additionally, and extra 15 minutes was spend at Yakushima.
Add to that, the extra fuel consumed during the mission with the altitude change due to bad weather.
And finally, because if the faulty fuel transfer pump, Bockscar could not use 640 gallons if fuel, but instead, had to carry that weight home.
So taking all of these actual events into consideration, could a modified Lancaster have made the exact same journey under the exact same conditions?
Suppose Bockscar was one of these unicorn Lancasters - would it have been able to follow the exact timeline of eventsbas the actual B-29 or would it have been lost in action?
I've seen a great deal of effort to try and "fit" a Pumpkin Bomb into it's bomb bay, so let's assume the fuselage was widened enough to safely accommodate it's dimensions.
Would it have had enough fuel to not only made the trip from Tinian to the rendezvous point, then on to the primary and secondary target then on to Iwo Jima (Okinawa only in an emergency)? For the record, the Silverplate B-29s had a capacity of 7,250 gallons of fuel.
And what about both the imposed drag penalty of the bulging fuselage as well as additional fuel burn for extended (unscheduled) loiter time?
Nearly an hour was spent trying to find a bombing solution for Kokura before moving on to Nagasaki. Additionally, and extra 15 minutes was spend at Yakushima.
Add to that, the extra fuel consumed during the mission with the altitude change due to bad weather.
And finally, because if the faulty fuel transfer pump, Bockscar could not use 640 gallons if fuel, but instead, had to carry that weight home.
So taking all of these actual events into consideration, could a modified Lancaster have made the exact same journey under the exact same conditions?
FLYBOYJ
"THE GREAT GAZOO"
No...
GrauGeist
Generalfeldmarschall zur Luftschiff Abteilung
Just had to put that out there, because I haven't seen any mission snafus taken into consideration.
Tibbets' mission went fairly well, but Sweeny's mission nearly ended in disaster.
So laying out clean waypoints (origin to destination) as a metric for comparison between the two types without factoring in variables (as happened) isn't going to work.
Tibbets' mission went fairly well, but Sweeny's mission nearly ended in disaster.
So laying out clean waypoints (origin to destination) as a metric for comparison between the two types without factoring in variables (as happened) isn't going to work.
The B-29 had almost double the TO weight of a Lancaster as well (7250USG = ~6000IG).
As I stated earlier, Sweeny made his decisions based upon his available fuel, with a different range available, he would have made different decisions. Losing an aircraft, via ditching, if necessary is quite a fair trade-off for potentially ending the war and saving, possibly, millions of lives.
As for drag, we have to consider the reduction due to removal of the front and upper turrets and the masking of the radome by the bulged bomb bay, so overall a probable reduction in drag.
GrauGeist
Generalfeldmarschall zur Luftschiff Abteilung
So what decisions would have Sweeny made?
Cut short the rendezvous?
Drop the bomb at Kokura through the clouds and smoke, hoping for the best?
Go on to Nagasaki and then hope they can make it far enough to reach a USN picket sub to ditch by?
What about all the important data onboard that will be lost?
What is the survival rate of Lancaster crews that historically ditched? Can Sweeny guarentee the safety of his crew doing the same?
Cut short the rendezvous?
Drop the bomb at Kokura through the clouds and smoke, hoping for the best?
Go on to Nagasaki and then hope they can make it far enough to reach a USN picket sub to ditch by?
What about all the important data onboard that will be lost?
What is the survival rate of Lancaster crews that historically ditched? Can Sweeny guarentee the safety of his crew doing the same?
FLYBOYJ
"THE GREAT GAZOO"
Yea, he would have flown the mission as planned and returned to Tinian!
And the Silverplate B-29 didn't require a bulged bomb bay!
Sweeny was prepared to drop by radar - that was his call to make and coastal targets generally provide an accurate radar mapping signal. With less fuel available Sweeny might have chosen to proceed to Kokura or Nagasaki, after 15mins at the Rendezvous point and made a visual drop.
B-29s ditched regularly during conventional bombing runs over Japan. War is hell and Sweeny and every other Allied pilot knew there were no guarantees about anything (C'mon how can you even ask such a question?). The vital data such as bomb yield can be estimated by on-board accelerometers and by post drop photo-recon. Aircrew can also exit via parachute over the ditching point, with the plane on autopilot.
Yea, he would have flown the mission as planned and returned to Tinian!
And the Silverplate B-29 didn't require a bulged bomb bay!
It's unlikely that Sweeny could have made it back to Tinian, even if he didn't delay for more than 15min at the rendezvous point, because of the faulty fuel pump (Groves states that 800USG of fuel was unavailable).
The title of this thread is The Lancaster as a potential nuclear bomber in 1945.
FLYBOYJ
"THE GREAT GAZOO"
It is - and I think it's potential has been shown to be less than adequate when compared to the Silverplate B-29!
FLYBOYJ
"THE GREAT GAZOO"
Trying to present a Lancaster mission profile based on the Bockcar debacle is just an attempt to hide the "Silverplate Lancaster's" limitations, you're just moving the gold posts closer. Sweeney was lucky he wasn't court-marshalled and Tibbets even revised his autobiography to dispel claims made my Sweeney to lessen the errors made. Thanks to General LeMay, Sweeney was spared Tibbets' wrath.
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Dash119
Senior Airman
I know it is a terrible source, but Wikipedia states;
1) Group Commander Colonel Paul Tibbets and Sweeney therefore elected to have Bockscar continue the mission. So if Tibbets approves the flight with the broken fuel transfer pump, how is this Sweeney's error?
2) Though ordered not to circle longer than fifteen minutes, Sweeney continued to wait for The Big Stink, at the urging of Commander Frederick Ashworth, the plane's weaponeer, who was in command of the mission. I understand that as PIC Sweeney is ultimately responsible for the aircraft, but if the Mission Commander is urging some action doesn't some responsibility for the delay fall on his shoulders?
FLYBOYJ
"THE GREAT GAZOO"
Sweeney had the ability to still refuse to take the aircraft and in hindsight should have. Tibbets approved this mission assuming it was to be flown as briefed. Sweeney's CO gave him a SPECIFIC order and he did not follow it. Even though Ashworth was the mission commander, Sweeney was still PIC and at the end of the day, it was Sweeney's decision.
You quoted Wikipedia - you seemed to neglect what Tibbets said to Sweeney upon his return.
SaparotRob
Unter Gemeine Geschwader Murmeltier XIII
Okay, where's that quote of Colonel Tibbet's found?
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