Theoretical Bomber question

[Waynos]

Guys, you know how the Avro Manchester was blighted by the Vulture engine, but the Lancaster was the best British heavy bomber of war?

What if a different approach had been made? Instead of creating the Lancaster what if a Griffon Manchester had been developed?

Would the engine have been available? Griffon Spitfire work began in 1940 so I suppose its possible. The conversion should have been more straightforward as you would still have a twin rather than the change to four engines.

Could it have worked? And how would you see a comparison between this Griffon engined 'Manchester IV' and the Manchester III that became the Lancaster? Anyone like to speculate? Oh and yes, 3, 4 or 5 blade props?

 

[Colin1]

Guys, you know how the Avro Manchester was blighted by the Vulture engine, but the Lancaster was the best British heavy bomber of war?

What if a different approach had been made? Instead of creating the Lancaster what if a Griffon Manchester had been developed?

Would the engine have been available? Griffon Spitfire work began in 1940 so I suppose its possible. The conversion should have been more straightforward as you would still have a twin rather than the change to four engines.

Could it have worked? And how would you see a comparison between this Griffon engined 'Manchester IV' and the Manchester III that became the Lancaster? Anyone like to speculate? Oh and yes, 3, 4 or 5 blade props?

Where would you employ it?
It's still a 2-engined bomber and we already have the Mosquito, the Beau, the Wellington and the Havoc filling that niche. It will undoubtedly be better at altitude than the Vulture-Manchester but it's not going to carry the bombload of a true RAF heavy; will that duty then fall solely to the Halifax? It may have prompted more positive design changes in the Stirling but I don't want to wander too far off-track here; the question that keeps popping up in my head is 'would a (markedly better) 2-engined Griffon-Manchester have been more bang-for-buck than a 4-engined Merlin-Lancaster'?

The B-29 employed 4-bladed screws for their mighty R-28s, I couldn't comment on whether the Griffon-Manchester could fully exploit 4 blades

 

[lingo]

I'm reading the book on Air Vice Marshall Wilfred Freeman now. He was for much of the war responsible to airframe and aero-engine research and development as well as ordering them into production. It appears that the Vulture problem was capable of being sorted, but it would take time - time that could more profitably be spent on Merlin development. He cancelled both the Vulture and the Peregrine( so the Whirlwind line had to close) so that Rolls Royce would concentrate on the Merlin. He originally thought the Griffon would replace the Merlin, but the old engine kept getting better and better so there wasn't the urgency to bring the Griffon into service - which was just as well as it had teething snags and needed further development. The Halifax was originally to have had a brace of Vultures, but Freeman told Handley Page to go for 4 Merlins before the design was frozen.
As to your interesting question, I believe 4 developed Merlins on a heavy (for the time) bomber was a much better bet than any other option.

 

[BombTaxi]

The Griffon was a prodigious gas guzzler compared to the Merlin - a severe shortcoming in a heavy bomber. Bomb-load would have been restricted by the two, rather than four engines as well. I think the RAF had already acknowledged that the four-engined heavy was the way to go, even if the first attempt (the Stirling) wasn't much cop, and had the Griffon been available, would have simply used four instead of four Merlins on the Lanc.

But a Manc with two nacelles each sporting a five-blade prop? It would look extremely cool 8)

 

[Waynos]

Where would I employ it? Good question. I was thinking purely in terms of it replacing the Manchester 1A in Bomber Command for the night assault on Germany. The typical load, I believe, on these raids was 8-10,000lb depending on distance to travel. The rather feeble Manc IA had a max load of just over 10,000lb so I suppose I was really asking 'given the Vulture output was 1,750hp (nominally) would a twin Griffon model fallen short of the Lancaster 1, by how much and in what areas'? I know the3 Warwick was intended to be a 'heavy' replacement for the Wellington, and it eventually saw service with the 2,500hp Centaurus, but I guess was still no match for the Lancaster given the historical record. It just makes me wonder 'what if?' I also think that 4 blades would have been a necessity for it, but confess that is no more than a gut feeling at this time with no attempt to research it yet.

Lingo, my question is prompted from a book on British bomber development and in there is states that the reason the Vulture didn't get the attention it needed was probably to do with it being dropped from the Warwick in favour of the Wright Cyclone and Bristoll Centaurus, leaving the Manc as its sole application, the same situation the Whirlwind and Peregrine were in.

Interesting to see that Freeman told HP to switch to Merlins for the Halifax. Is this his own claim? As far as I am aware Volkert was pressing for the HP 56 to switch to Merlins throughout its design as he was not confident that the Vulture would work as advertised. Unless he meant 'told them to' as in 'oh, go on then!'

I agree that the solution that HP (and Avro) came up with was the best one.

I thyink the Stirling is unfairly maligned by History. When you compare it to it predecessor, the Whitley, it delivered twice the bombload at 25% higher speed over greater range. An acheivement not to be sniffed at for a bomber concieved in 1936- before the Whitley had entered service, in which Shorts were quite falsely told to keep the span to 100ft on.

But a Manc with two nacelles each sporting a five-blade prop? It would look extremely cool

Yeah, wouldn't it just...........and maybe a 102ft wingspan?

 

[Shortround6]

As far as the Vultures problems being easy to sort out I would note that no successful liquid cooled inline engine ever used 4 connecting rods on one crank throw. Rolls certainly never tried it again.
While later Griffons certainly exceeded the Vultures power rating I am not so sure that would have been the case in 1941. The Griffons 36.7 liters would have had to work pretty hard to equel the Vultures 42.5 liters. ANd considering the VUlture was SUPPOSED to run at 3200rpm comared to the Vultures 2750rpm I don't think there was much hope of replacing Vultures with Griffons on a 1 to 1 basis.

 

[Jabberwocky]

Actually, the Griffon wasn't a "prodigious gas guzzler" compared to the Merlin. It actually consumed less fuel per horsepower than its smaller stablemate.

A Merlin II consumed roughly 0.63 lbs of fuel per hp per hour.

This improved through the war though. Later Merlin engines (100 series) consumed roughly 0.54 lbs per hp per hour (or about 15% better).

A Griffon VI consumed roughly 0.50 lbs of fuel per hp per hour

What made the Griffon a fuel hog was that it operated at higher power levels than the Merlin. RAF tests found that the Griffon powered Spitfire XIV consumed about 25% more fuel than the Spitfire IX, but had similar range as it flew about 25% faster.

 

[lingo]

Interesting to see that Freeman told HP to switch to Merlins for the Halifax. Is this his own claim?

No Sir. The book I am referring to is the biography called Wilfred Freeman by Anthony Furse, which is a superb piece of research.

I thyink the Stirling is unfairly maligned by History. When you compare it to it predecessor, the Whitley, it delivered twice the bombload at 25% higher speed over greater range. An acheivement not to be sniffed at for a bomber concieved in 1936- before the Whitley had entered service, in which Shorts were quite falsely told to keep the span to 100ft on.


I entirely agree. It was the first 4 engined monoplane bomber to enter RAF service and the design was severely constrained by having to fit in a (then) standard hangar. Due to the rush to get it into quantity production the design was frozen at an early date, leading to the later problems although these would have been eased had the intended version of the Hercules engine been available.

 

[Colin1]

I thyink the Stirling is unfairly maligned by History. When you compare it to it predecessor, the Whitley, it delivered twice the bombload at 25% higher speed over greater range. An acheivement not to be sniffed at for a bomber concieved in 1936- before the Whitley had entered service, in which Shorts were quite falsely told to keep the span to 100ft on

I entirely agree. It was the first 4 engined monoplane bomber to enter RAF service and the design was severely constrained by having to fit in a (then) standard hangar. Due to the rush to get it into quantity production the design was frozen at an early date, leading to the later problems although these would have been eased had the intended version of the Hercules engine been available

What would the practicality value
of folding wings have been on large bombers? They didn't need to flit around the sky like a single-engined fighter, so torsional rigidity wasn't nearly the same issue. Would the payload have imposed unacceptable load forces on the 'hinge'?

If load forces weren't an issue then I'm surprised someone didn't borrow the idea from the Navy to negate some very expensive accommodations to the growing size of heavy bombers.

 

[Waynos]

From what I've read It wouldn't even have been necessary. the Lancaster(102ft) and the Lincoln (120ft) were both housed in standard unmodified hangars. from the little bit of checking I've done the max opening of the Hangar doors was 126ft, so I don't actually know where the 100ft restriction was gotten from? The Short S.36 'Super Stirling' of 1941 was schemed with a 135 ft span and a 24,000lb bomb load and the power of 4x2,500hp Caentaurus' but not with folding wings.

I think the main drawback of the Stirling was its 'bomb cell' arrangement which meant nothing bigger than a 2,00pounder could be accomodated, compared to the Lancs voluminous continuous bomb bay, every other shortcoming could have been fixed through development. If you compare the Stirling I with the Fortress I or B-17C, ther newer design from Short was head and shoulders above it in capability and defensive firepower, but the B-17 was continuously devel;oped and the Stirling was not.