Lancaster X aircraft, Packard Merlin 28, 38, and 224 engines

JDCAVE

Senior Airman
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Aug 17, 2007
According to Harry Holmes book, "Avro Lancaster, the Definitive Record, the Canadian built Lancaster X aircraft were variously powered with Packard Merlin 28, 38, and 224 engines. I have examined the Accident cards available to review here:
And have excerpted the following:
Lancaster X engine types.jpg


Note that only KB.700 had the PM 28 engines. I want to ascertain the serial number where the Lancaster X's were first fitted with the Packard Merlin 224 engines. I believe it was KB.776 but would like confirmation. This a/c was lost on an operation to Essen, 23/24-October-1944, pilot S/L W.C. McGuffin. The Loss cards do not record engine type.

Jim
 

JDCAVE

Senior Airman
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Aug 17, 2007
I should add that KB.778 definitely had the PM 224 engines, as recorded in loss card. The aircraft was crashed in the Ardennes Mountains on 5/6-March-1945. The pilot was too low could not climb due to icing. Dad was on that op. This supports my believe that KB.779 also had the PM 224's. Dad had 7 ops on that a/c.

Jim
 

33k in the air

Staff Sergeant
807
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Jan 31, 2021
According to Avro Lancaster by Richard Marks (Osprey Publishing):

4 Packard Merlin 38 (KB700–KB774)
4 Packard Merlin 228

"The first 75 aircraft were fitted with Packard Merlin 38 engines, with the remaining aircraft fitted with the Packard Merlin 228 engine."

Note that book actually does say Merlin 228 engines, which I presume is a typographical error.


According to The Avro Lancaster, Manchester and Lincoln — A Comprehensive Guide for the Modeller by Richard A. Franks (SAM Publications):

4 x Packard Merlin 38 (a/c KB700–KB774)
4 x Packard Merlin 224 (a/c KB775 onwards)
 
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Geoffrey Sinclair

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Sep 30, 2021

KB700 has Merlin 28, KB701 no engine type, KB702 and 3 are missing, KB704 has Merlin 38. From then on until KB775 where the aircraft card is present and the engine listed it is Merlin 38, with the following exceptions

KB731 Merlin 31 or a very skinny 8?.
KB745, KB752, KB754, KB756 Merlin 33

Then there is a change over

Merlin 224, KB776, KB777 (Overwriting 38?), KB779, KB781
Merlin 38, KB778, KB780, KB782

KB783 onwards where the aircraft card is present and the engine listed it is Merlin 224, except Merlin 38 in KB799. Then comes any engine changes in service.

According to the British, Merlin 28 production ended in February 1943, 5,200 built. Merlin 31 had 560 built March 1942 to February 1943. Merlin 38 production began in March 1943, Merlin 33 in April 1943. The report ends in November 1943, by which time 880 Merlin 33 (production ending in October?) and 6,286 Merlin 38 had been built. Production of single stage Merlins for the US ending in March 1943.
 

Engineman

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Dec 26, 2021
Hi,
I have the Merlin Mk 31 and 33 listed for Canadian and Australian built Mosquito, with the "reverse-flow" cooling. Not impossible that they were reworked I guess.

Eng
 

JDCAVE

Senior Airman
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Aug 17, 2007
For all of us, 80 years later, PM38 and 224 engines are just numbers. It was much more than that for dad. He hated the aircraft with the PM 38 engines. This is what he says about KB.779, Oberhausen, 1-November-1944:

“At this time, I was flying "B"-Baker [KB.779] and it was a very good aeroplane, it was a very FAST aeroplane, the first "B"-Baker. I was very pleased to be on it. We had a lot of fun.”

KB.721:

“And I remember we came back from that, only to find that our aircraft "B"-Baker [KB.779] had been shot down and was missing when we were away on leave. And the "new" "B"-Baker was a clapped-out old plane—KB.721 and we did not like it at all.“

Jim
 

JDCAVE

Senior Airman
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Aug 17, 2007
A bit more sleuthing. As mentioned in an earlier thread, the 18-boost aircraft were approved for a higher "all-up-weight" of 67000 lbs. The 44-Squadron Bomb Aimer's Briefing record for the raid to Bohlen records different loads for different aircraft:

Bomb Aimers Briefing Bohlen 18 Boost AC loads.jpg


The 44 Squadron ORB confirms these loads by squadron code letter:

Screenshot 2022-12-09 223714.jpg


The Form 78 Aircraft Movement cards (thank you Geoffrey) records the engines on these aircraft. These show that the Lancaster Mk I's with the higher loads were powered with the Merlin 24 engines. There is one Lancaster III with a 10,000 lb load and this is powered with the PM 224 engine.

The important take-away I have from this is the Lancaster III with the PM 224 had a 10,000 lb load. So why weren't the Lanaster X's with the PM 224's permitted with a higher load? On the same night as this raid to Bohlen, Dad flew KB.865 to Chemnitz. He had a 2154 gallon petrol load and the same bomb load as all of the lancasters with the PM-38 engine (7,500 lbs). He could have carried 9,500 lbs. In fact, at no time, Feb-April 1945, did 6-Group Lancaster X's with PM-224 carry a higher load than the PM-38 equipped aircraft. A question for the OC 6-Group I suppose.

Jim
 

Engineman

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Dec 26, 2021
Not sure I follow your question exactly Jim. The only points that I might make are that the loads might have physically had a fit/release limit in the bomb bay that did not weigh the max. Also, there might have been a policy/restriction on engine use for engineering reasons. However, the book difference in performance of the engines for T/O was a considerable, 28's and 38's with 1390hp, 24's and 224's with 1610hp. Cruise performance was similar between all these types so, maybe policy on cruise performance (speed/altitude) was a factor, considerably heavier aircraft with same cruise power would be slower/lower.

Eng
 

JDCAVE

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Aug 17, 2007
Hi Eng: the Canadian built Lancasters were capable of the same Bomb loads as those built in the UK. 6-Group Lancaster took a bomb load of 14,000 lbs to Wangerooge on 25-April-1945. And as mentioned above, the 5-Group Lancs had different bomb loads depending on engine type. 6-Group flew a longer route than squadrons further south in the UK, to the same target, but the Bohlen force flew a pretty lengthy route that night. I would have to calculate the distances and compare with 6-Group. Bohlen route in Yellow:


The Bohlen force followed along just behind the Chemnitz force before turning SSE towards Bohlen.

Jim
 
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Engineman

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Dec 26, 2021
Hi Eng: the Canadian built Lancasters were capable of the same Bomb loads as those built in the UK. 6-Group Lancaster took a bomb load of 14,000 lbs to Wangerooge on 25-April-1945. And as mentioned above, the 5-Group Lancs had different bomb loads depending on engine type. 6-Group flew a longer route than squadrons further south in the UK, to the same target, but the Bohlen force flew a pretty lengthy route that night. I would have to calculate the distances and compare with 6-Group. Bohlen route in Yellow:


The Bohlen force followed along just behind the Chemnitz force before turning SSE towards Bohlen.

Jim


Hi Jim,
Yes, no probs with your details. I am just responding to your points that concentrate on engine types to some degree and trying to offer possible considerations that might apply from my own experience of Ops on more modern types and known engine data.
I would have thought that there is strong PRO data on these specific raids? Beyond that, the Command and Group orders at the time would have had all manner of specifics that might not be recoverable today. Also, I would suggest there were also specific reasons that peculiar things were done.
You might find that you can access the F540 from the particular squadrons and discover interesting info, although the quality of F540 information is a mixed bag.
Great to hear these raid specific details!

Cheers

Eng
 

JDCAVE

Senior Airman
322
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Aug 17, 2007
Hi Jim,
Yes, no probs with your details. I am just responding to your points that concentrate on engine types to some degree and trying to offer possible considerations that might apply from my own experience of Ops on more modern types and known engine data.
I would have thought that there is strong PRO data on these specific raids? Beyond that, the Command and Group orders at the time would have had all manner of specifics that might not be recoverable today. Also, I would suggest there were also specific reasons that peculiar things were done.
You might find that you can access the F540 from the particular squadrons and discover interesting info, although the quality of F540 information is a mixed bag.
Great to hear these raid specific details!

Cheers

Eng
Yes, I’ve gone through the ORB’s (541’s) for these and I’m certain on the 419 and 428 squadron bomb loads. For the most part they match the Form B’s (operational orders). I haven’t looked at 1-Group though, to see if there were different bomb loads by engine type.

Jim
 

ThomasP

Tech Sergeant
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Apr 17, 2017
midwest USA
re lower bomb loads for the Lancaster Mk X (and possibly other Mks at different times in the war)

A number of years ago I ran across some notes on Mods to the Lancaster. At some point there several Mods that allowed higher all-up TOGW. One was a structural Mod, and the description of the Mod said that this was necessary if the airframe was to be cleared for full bomb load and full fuel load in the wings at the increased TOGW. Unfortunately that is all I remember on that Mod.

Also, there were 3 different bomb bay/bomb bay doors set-ups. The 1st (original) type only allowed bombs upto 2000 lbs. The 2nd type allowed the 4000 lb 'cookie' (Ø2' 6"). The 3rd type allowed the 8000 lb 'cookie' (Ø3' 2"). (and maybe the 12,000 lb 'cookie'??).

Is it possible that not all the Sqn aircraft - particularly the Mk X - had the same/necessary Mods?

KB721 is listed as being fitted with Merlin 38 during tests at A&AEE to determine the Lancaster Mk X TARE. The date of the tests may have been in early 1944 as the document has a SECRET stamp dated 27 May 1944.
 

EwenS

Staff Sergeant
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Oct 19, 2021
The 12,000lb HC Bomb had an identical diameter (38”) to the 8,000lb HC weapon. Even the official manuals describe it as an 8,000lb with an extra section. The 12,000lb Tallboy Deep Penetration weapon was also had a 38” diameter and could be accommodated within the same bomb bay doors.

The 4,000lb Cookie had a 30” diameter as noted.
 

33k in the air

Staff Sergeant
807
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Jan 31, 2021
The important take-away I have from this is the Lancaster III with the PM 224 had a 10,000 lb load. So why weren't the Lanaster X's with the PM 224's permitted with a higher load? On the same night as this raid to Bohlen, Dad flew KB.865 to Chemnitz. He had a 2154 gallon petrol load and the same bomb load as all of the lancasters with the PM-38 engine (7,500 lbs). He could have carried 9,500 lbs. In fact, at no time, Feb-April 1945, did 6-Group Lancaster X's with PM-224 carry a higher load than the PM-38 equipped aircraft. A question for the OC 6-Group I suppose.

From what I've seen, Lancaster (and Halifax) bomb loads are incredibly varied. Even aircraft dispatched from the same squadron sometimes carried different loads. Some time ago I posted the loads for 433 Squadron, which included both bombers. I recently compiled the figures for 106 Squadron, but have not yet posted them. There were 257 different load outs, (although to be fair a few of these might have been typos in the original ORBs or in my data entry).

Part of the issue with bomb loads was shortages of preferred bombs, with the 1,000-lb MC and 500-lb MC being the most affected, along with insufficient numbers of 4-lb cluster projectiles. Such shortages forced the use of lighter or older GP bombs, or in 1944, the use of American bombs.

There were differences in Group practices as well. This is mentioned in Martin Middlebrook's The Berlin Raids — The Bomber Battle, Winter 1943–1944. In Appendix 3, a comparison is made of 1 and 5 Group results during the battle, and 1 Group aircraft carried a heavier average bomb load than its 5 Group counterparts. This led to the practice of some crews, in heavily laden aircraft, to jettison part of their bomb load over the North Sea in order to lighten the aircraft and allow it to climb to a higher altitude.
 

Engineman

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Dec 26, 2021
. This led to the practice of some crews, in heavily laden aircraft, to jettison part of their bomb load over the North Sea in order to lighten the aircraft and allow it to climb to a higher altitude.

This perhaps backs-up my proposition that despite the greater MTOW capability of some aircraft/engines discussed here (mainly due to increased T/O power rating), the engines here had the same continuous/cruise power ratings that would define the cruise speed and altitude performance. I can imagine that no one wanted to be at the lowest altitude and speed in a heavy aircraft, much the same as no one wanted to fly the aircraft with the worst performance.

Cheers

Eng
 

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