The Lancaster as a potential nuclear bomber in 1945

[Greyman]

... arguing about ... the use of an aeroplane that didn't enter scale production is just wishful telescoping.

In a fantasy scenario (no B-29) it's incorrect to assume everyone involved would follow the exact same course of action as happened in reality.

If we change the reality of the B-29 existing we have to change the reality of everyone's reaction to that fact.

The opportunity to completely avoid Operation Downfall would be up for grabs. I think it's reasonable to assume getting a few Lancaster VIs or (Lincoln Is) up to snuff would have received a bit more attention and resources than it did.

I also think it's unreasonable to set the maximum level of acceptable risk of this pivotal mission to that of what Enola Gay and Bock's Car experienced.

 

[Shortround6]

I would note that the performance claimed for the MK VI with two turrets removed seems to be at odds with performance here.

http://www.wwiiaircraftperformance.org/Lancaster/jb675-level-speeds.jpg

about 315mph at 62,000lbs, turret fit not stated.

and from the information in Flight magazine on the Lincoln.
lancaster | 1946 | 0103 | Flight Archive

granted it is a Magazine and not an official test but the "gee whiz" attitude of the writer leads one to believe he wasn't being conservative. It is a January 1946 issue.

from the first paragraph " At that time we referred to the Lincoln as " the mightiest bomber in the world," and now, having had an opportunity of examining the machine in detail, our original opinion is, if anything, emphasised. "

Italics by me. The B-29 was hardly a secret. So one can only assume more than a little patriotic flag waving.

 

[Greyman]

... about 315mph at 62,000lbs, turret fit not stated.

- front, mid-upper and rear turrets fitted
- extended bomb-aimer's cupola
- H2S blister
- no exhaust shrouds (not stated but appears this way in a photo from an earlier trial)

 

[Shortround6]

Thank you. I am not sure that yanking the top turret and smoothing up the nose by pulling the turret and bomb aimers position is going to be worth 30mph. Especially if the plane with the turrets was running 6000lbs or more lighter than the plane that claimed 345mph.

 

[RCAFson]

ed.

and from the information in Flight magazine on the Lincoln.
lancaster | 1946 | 0103 | Flight Archive

Of interest is the effect of weight on service ceiling and speed.

 

[RCAFson]

Thank you. I am not sure that yanking the top turret and smoothing up the nose by pulling the turret and bomb aimers position is going to be worth 30mph. Especially if the plane with the turrets was running 6000lbs or more lighter than the plane that claimed 345mph.

We (and I) don't know what aircraft weight was at the stated speed. However 345mph seems quite reasonable to me that if the weight was, say ~55000lb.

 

[GrauGeist]

It seems to me that the problems with the B.VI's engine synchronization would have meant erratic fuel consumption that could not be predicted for a critical long-range mission, putting the mission at risk.

 

[RCAFson]

YEP!

From Wiki;
"The more powerful engines proved troublesome in service and were disliked by ground maintenance staff for their rough running and propensity to 'surge and hunt', making synchronisation impossible. This was caused by variations in the fuel/air mixture and over time would damage the engine."

Lancaster VI service ceiling of 28,500 (as posed by RCAF son) - both Atomic missions dropped their bombs at 31,000 feet.

So as mentioned earlier - Could the Lancaster deliver a nuclear weapon? I believe so. As good as a B-29? NO. With greater risk? Definitely!

I also have issues with a single pilot cockpit.

Doubtless the engines would have to be changed out frequently, but that seems acceptable given the costs of the weapon to be dropped and the low cost of a Lancaster compared to some other bombers. The flight engineer typically had the ability to fly the aircraft from his station.

Lancaster VI service ceiling was at 65000lb TO weight with full armament and armour. Weight over the target would be much less than 65k lbs. and I would guesstimate that it would be about 57k lbs in an aircraft with the two forward turrets deleted with a consequent increase in speed and ceiling.

A post war B29 at Max TO weight (140k lbs) had a service ceiling of ~24000ft, increasing to 35.6k ft at 120k lbs and 39.6k ft at 101.3k lbs.

Bockscar dropped a ~50% more powerful bomb at ~28.9k ft, versus ~31.6k ft for Enola Gay. Enola Gay could have probably dropped at 24k ft quite safely.

 

[GrauGeist]

Enola Gay could have probably dropped at 24k ft quite safely.

Except for the extremely accurate Japanese AA which would have brought it down like so many other B-29s - there was a reason for the specific altitude that the A-Bombs were to be dropped.
The primary reason was AA and the other was the allow for the aircraft to egress the area before being over-taken by the shockwave.

 

[RCAFson]

It seems to me that the problems with the B.VI's engine synchronization would have meant erratic fuel consumption that could not be predicted for a critical long-range mission, putting the mission at risk.

Lancaster VIs flew a number of combat missions and did extensive flight testing so their characteristics would have been well known. However, apparently a change to 4 bladed props solved most of the problems.

 

[GrauGeist]

Lancaster VIs flew a number of combat missions and did extensive flight testing so their characteristics would have been well known. However, apparently a change to 4 bladed props solved most of the problems.

You do realize that you're staunchly defending 9 aircraft that had a questionable service span of less than a year and were replaced by more reliable versions, all in the hopes of making a point that these would be the golden steeds of an Atomic delivery program?

Think about that carefully the next time you poke at anyone who is trying to justify a "wunderwaffe" aircraft

 

[Greyman]

You do realize that you're staunchly defending 9 aircraft that had a questionable service span of less than a year and were replaced by more reliable versions, all in the hopes of making a point that these would be the golden steeds of an Atomic delivery program?

Think about that carefully the next time you poke at anyone who is trying to justify a "wunderwaffe" aircraft

The Merlin 85 issues seem to have been worked out in time (see Lincoln).

There was probably a reason for the lack of effort/production of the Lancaster VI (also see Lincoln).

"... in the hopes of making a point that these would be the golden steeds of an Atomic delivery program?"

That's the entire point of this thread, yes.

a) all other options are off the table​

b) can the Lancaster work​

 

[RCAFson]

You do realize that you're staunchly defending 9 aircraft that had a questionable service span of less than a year and were replaced by more reliable versions, all in the hopes of making a point that these would be the golden steeds of an Atomic delivery program?

Think about that carefully the next time you poke at anyone who is trying to justify a "wunderwaffe" aircraft

There was more than 9 aircraft, as there were several Lincoln prototypes (Lancaster IV) and the Lincolns themselves and as we've discussed there was little urgency for the development of a long range, high altitude Lancaster but despite that one was developed and flew a number of combat sorties.

If the bomb had been developed historically, but post war, and consequently there was no Silverplate B-29 program and no A1 priority for B-29 development and we had to decide, now, in retrospect, if the B-29 was mature enough to have been worth trying to modify it to carry LITTLEBOY AND FATMAN if they had been available, what would we decide?

We'd be looking at the expense, the needed structural and reliability improvements and the operational track record of the B-29 and I'll bet we'd conclude that the B-29 looked good on paper but just wasn't ready.

 

[Shortround6]

Thank you. I am not sure that yanking the top turret and smoothing up the nose by pulling the turret and bomb aimers position is going to be worth 30mph. Especially if the plane with the turrets was running 6000lbs or more lighter than the plane that claimed 345mph.

You can disagree with my assessment but how about coming up with something to show how it is wrong.

Some of my opinion is based off comparing the normal Lancaster to the Lancastrian airliner.

Which, despite running lighter than the Lancaster bomber, (53,000lbs mean weight vs 55,000lbs for the MK III Lancaster) was not 30mph faster despite the longer, better faired nose, the longer faired tail, and absence of H2S blisters (or any other kind) on the belly of the aircraft.
It was about 20mph faster at max weak mixture. Power levels are going to be very similar as the Merlin 24 in the Lancastrian, the Merlin 22, 32,38s in the Lancasters all ran at 2650rpm and 7lbs boost for max weak mixture. The Merlin 24 was allowed 18lbs boost due to a stronger clutch in the supercharger drive.
The Merlin 85 was rated at 2650rpm and 7lbs boost for max weak cruising in low gear and 2850rpm and 7lb in high gear. The Merlin 85 was a low altitude two stage engine. It was rated at 1580hp at 16,000ft in high gear (18lbs boost) The Merlin 24 was rated at 1510hp at 9250ft in high gear (18lbs of boost) so yes the Merlin 85 will give 7-8,000ft more ceiling.

The Lancastrian airliner was supposed to have a max speed of 310mph at 12,000ft. while weighing 53,000lbs.
Granted the Lanc Mk VI will be flying higher but getting it to 345mph is going to take an awful lot of doing.

BTW here is a report on the difference between standard conditions and tropical conditions as regards the Lancaster.
http://www.wwiiaircraftperformance.org/Lancaster/Lancaster_I_PD435_Performance.pdf

Make of it what you will but I think the 28,500 ceiling for the Lancaster MK VI is in serious jeopardy.

See part where the service ceiling of the Lancaster (with Merlin 24s) at 70,000lbs dropped from 20.100ft to 15,700ft and it took 61 minutes to reach the lower height vs 51 minutes to reach the higher altitude.

The Merlin 85s will improve things (ceiling especially, climb times not so much) as will running at a lighter weight as fuel is burned off but the the idea of getting a Lancaster VI to the same operating altitudes as a B-29 in tropical conditions seems to be an illusion.

 

[FLYBOYJ]

Doubtless the engines would have to be changed out frequently, but that seems acceptable given the costs of the weapon to be dropped and the low cost of a Lancaster compared to some other bombers. The flight engineer typically had the ability to fly the aircraft from his station.

Not the same having a dedicated copilot along side the PIC as another set of eyes and to help with the workload. The single pilot Lancaster configuration was always an operational risk based on need but in the end is/ was another outdated aspect of the Lancaster.

 

[FLYBOYJ]

Bockscar dropped a ~50% more powerful bomb at ~28.9k ft, versus ~31.6k ft for Enola Gay.

My sources show both bombs dropped at just over 31,000 ft, what's your source for that?

 

[RCAFson]

My sources show both bombs dropped at just over 31,000 ft, what's your source for that?

Here's the official history:

At any rate, it was Bock's Car, sans Bock, that carried the bomb. (See msg., Wright-Patterson AFB to Hq. USAF, 19 May 1946; 509th Composite Group, Operations Order No. 39, 8 Aug. 1945; 509th Composite Group, Final Mission Report No. 16, 9 Aug. 1945; and interview with Frederick C. Bock by J. L. Cate, 23 Nov. 1952.)

at both targets. Sweeney's plane reached the rendezvous point--Yakujima off the south coast of Kyushu--at 0909, one minute ahead of schedule, and was joined three minutes later by Bock's instrument plane. Bock spotted the other observation plane, piloted by Maj. James I. Hopkins, but lost contact; Sweeney never saw Hopkins' plane and after circling for three-quarters of an hour he and Bock headed for Kokura without it. There the weather had closed in meanwhile and Sweeney's bombardier, Capt. Kermit K. Beahan, made three runs without getting a glimpse of the target. With gas running low (600 gallons were trapped in the bomb-bay tank) and a few enemy fighters rising to investigate, Sweeney consulted with Beahan and Comdr. Frederick L. Ashworth (USN), the bomb commander and weaponeer. They decided to try the secondary target, make one run, and drop the bomb-visually if possible or by radar if not; this last decision, which ran counter to Sweeney's orders, was made on Ashworth's responsibility because of the shortage of fuel. Over Nagasaki they found 8/10 cloud and the run-in was 90 per cent by radar," but at the last second Beahan found a hole in the cloud and let go. It was then 1058 Nagasaki time.59

Sweeney banked his plane sharply and pushed down from his 28,900-foot altitude. A minute later, when the explosion came, "it was as if the B-29 were being beaten by a telephone pole"; five separate shocks were felt, and in general the turbulence seemed worse than that experienced over Hiroshima, though the reports of what followed read much like the earlier ones. Sweeney's signal to Tinian was apparently not received. He headed for Okinawa, frequently used by B-29's in distress after Kyushu strikes, and brought the Bock's Car down safely in an emergency landing at 1400 with only a few gallons of fuel left. Bock came in soon after and together then went on to Tinian; all three planes were home by 2339.60
HyperWar: The Army Air Forces in WWII: Vol. V--The Pacific: MATTERHORN to Nagasaki [Chapter 23] (pages 719-720 - my emphasis)

 

[RCAFson]

You can disagree with my assessment but how about coming up with something to show how it is wrong.

Some of my opinion is based off comparing the normal Lancaster to the Lancastrian airliner.
View attachment 529317
Which, despite running lighter than the Lancaster bomber, (53,000lbs mean weight vs 55,000lbs for the MK III Lancaster) was not 30mph faster despite the longer, better faired nose, the longer faired tail, and absence of H2S blisters (or any other kind) on the belly of the aircraft.
It was about 20mph faster at max weak mixture. Power levels are going to be very similar as the Merlin 24 in the Lancastrian, the Merlin 22, 32,38s in the Lancasters all ran at 2650rpm and 7lbs boost for max weak mixture. The Merlin 24 was allowed 18lbs boost due to a stronger clutch in the supercharger drive.
The Merlin 85 was rated at 2650rpm and 7lbs boost for max weak cruising in low gear and 2850rpm and 7lb in high gear. The Merlin 85 was a low altitude two stage engine. It was rated at 1580hp at 16,000ft in high gear (18lbs boost) The Merlin 24 was rated at 1510hp at 9250ft in high gear (18lbs of boost) so yes the Merlin 85 will give 7-8,000ft more ceiling.

The Lancastrian airliner was supposed to have a max speed of 310mph at 12,000ft. while weighing 53,000lbs.
Granted the Lanc Mk VI will be flying higher but getting it to 345mph is going to take an awful lot of doing.

BTW here is a report on the difference between standard conditions and tropical conditions as regards the Lancaster.
http://www.wwiiaircraftperformance.org/Lancaster/Lancaster_I_PD435_Performance.pdf

Make of it what you will but I think the 28,500 ceiling for the Lancaster MK VI is in serious jeopardy.

See part where the service ceiling of the Lancaster (with Merlin 24s) at 70,000lbs dropped from 20.100ft to 15,700ft and it took 61 minutes to reach the lower height vs 51 minutes to reach the higher altitude.

The Merlin 85s will improve things (ceiling especially, climb times not so much) as will running at a lighter weight as fuel is burned off but the the idea of getting a Lancaster VI to the same operating altitudes as a B-29 in tropical conditions seems to be an illusion.

We'd need to see similar data for the B-29 to make a valid comparison. However, conditions at Tinian in August are not the same as Tropical Summer in India:

Saipan International, MP History | Weather Underground (this data is for Aug 1955)




Comparing an lancastrian with a FTH of 12K ft to one with a FTH of 18-20k ft is fraught with difficulties. if we look at the Lincoln data we can see an increase in speed of ~10mph due to a reduction in weight and if the aircraft were streamlined by removing the forward turrets and fairings, then another 20mph increase seems likely.

A Lancaster 1 at 60k lbs and 12K ft would have a maximum speed of ~278mph which is 32mph slower than the Lancastrian at your stated 310mph at 12k ft.

 

[RCAFson]

Not the same having a dedicated copilot along side the PIC as another set of eyes and to help with the workload. The single pilot Lancaster configuration was always an operational risk based on need but in the end is/ was another outdated aspect of the Lancaster.

The aircraft has a 2nd pilot when needed and an autopilot. Not requiring a co-pilot significantly reduced Lancaster operational costs.

 

[Greyman]

Found some figures for speed increases via turret removal:

Mid-Upper FN50a
490 lb total (turret, mounting, 2 guns, 2000 rounds) I don't think this includes the gunner, so maybe add another 200 lb
-10 mph cruising speed, -12 mph max speed