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Is the Avro Manchester Maligned Too Much And Did It Get Sorted Out?


JohnT

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I had always understood the conventional view of the Manchester was that it was a duffer and Avro was saved by the Lancaster development. Just about everything I read in books like the SAM datafile covering the Manchester, Lanc and Lincoln say so.

 

However when reading Martin Bowmans book "Flying into the Flames of Hell" Chapter 3  re one Ernie Rodley pilot he writes :-

 

" Later, we reached the last phase of the course, which was to convert on to the Manchester.  Somewhat awed by the size of this monster, I found it a delight to fly.  Everything worked - after all, they were nearly new - and I was relieved to find that I had not completely lost the art of landing.  Actually the Manchester was even nicer to fly than the Lancaster was. With 12 feet less in wingspan and a closer engine mass, it had a rate of roll like a fighter.  The landing, with a trickle of engine to offset the high wing loading, was like that of the Anson.  Then, once on the ground, the huge 16 feet props bit into the air, decelerating the machine like wheel brakes.  The Vulture was now very dependable.  The big end trouble had been overcome and one only has to remember how the Manchester took the brunt of the work at the Lancaster Conversion Units to realise what a good job Rolls Royce had done."

 

The author of those remarks was an ex Wellington pilot who was pre war RAFVR and with over 1000 hours went first to instructing on Wellingtons before doing a tour on ops.  Its an interesting set of comments rather going against the flow.

 

Similarly I recall speaking with a flight engineer who flew Stirlings, Lancasters and Halifaxes.  His comment was that the Halifax B111 was developed from the poorer earlier marks and was every bit as good as the Lancaster in every way and better some except that all important load carrying capacity.

 

Thought to share to Manchester comments and wonder if anyone has read similar

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I’ve just been re-reading the excellent book ‘legend behind the lancaster’ by Robert Kirby. The Manchester was in constant evolution and the problems many due to it being thrust into operational service before it was ready, however, handling appeared to be good. The 3rd tail provided better lateral stability than the Lancaster despite issues with airflow from the mid upper turret. It was underpowered unfortunately so whilst handling may of been good, single engine handling was more of a steady glide and clime rate poor. There were some crew who never experienced any engine problems, so there will inevitably be mixed perceptions of the Manchester by those that flew it/ on it

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I think the Vulture could have been sorted out given the attention needed. There was nothing fundamentally wrong with it and I'm sure it would have gained a healthy reputation had circumstances been different. It, and the Manchester powered by it, were victims of being a Rolls Royce design that couldn't get the refinement effort required due to Rolls Royce already making a superb engine which was in huge demand.

 

The Sabre was also a thoroughly crap engine at a similar stage of its evolution. It became famous in a good way because Napier didn't have anything more pressing to do than get it working.

 

Rolls Royce, not having the attention available to give the Vulture, worked around the big end bearing failures and heat dissipation problems by reducing the maximum engine RPM. As we all know power is a function of torque x RPM, so that also limited the power. That in turn constrained the Manchester.

 

Rolls Royce were fairly confident they could sort out the Vulture, but they were just too busy making Merlins.

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Yes indeed the basic airframe was good, no excellent. But the Vulture was the let down. It wasn't the only time the Merlin engine transformed a good airframe into a war winner. I suppose the Merlin was the war winner on its own.

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13 minutes ago, noelh said:

. It wasn't the only time the Merlin engine transformed a good airframe into a war winner. I suppose the Merlin was the war winner on its own.

 

Tell that to Halifax crews.  It wasn't a great success on the Beaufighter or Wellington, either.  Life is never that simple.

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The Vulture engine was a good idea, get two engines for the price of one and all the weight inboard..two V engines,  stuck together , an X Block but  bit of a mess with various failings. So on to the Lancaster that carried a big load and they got the Merlin, probably THE engine of WW2. Not surprising the Manchester wasn't missed. It spurred on two giants of WW 2 aviation.

Edited by bzn20
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Your post about two engines for the price of one immediately reminded me of the problems with He177.

 

Also interesting point made by Graham too.  Gets you thinking why did certain types seem to respond better with certain engines?  I am sure an engineer will know.

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4 minutes ago, JohnT said:

with certain engines

Not sure but were they heavier than the original engine and/or was the weight shifted fwd, longer engine than the radials moving the C of G from the designed position . Could be an aerodynamic reason but can't see that, the Merlin has a smaller cross section.

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For the Mustang in particular it definitely wasn't that the Merlin was inherently much better as an engine core than the V-1710, but rather that Rolls Royce were deep involved in variable supercharging whereas Allison put their efforts into turbocharging.

 

The P-51A was weak on the single stage supercharged Allison and brilliant on the Mk.IX Spitfire's two speed twin stage supercharged Merlin. The Allison was a perfectly good engine in the P-38 designed for turbochargers though. Had someone decided to try a Merlin X in the Mustang it would have been no better a long range high altitude escort fighter than the A model.

 

A Merlin especially isn't an engine but a lineage. Parts commonality between early and late Merlins is very low.

 

Particular aircraft which did or didn't work with Merlins isn't so much about the size and shape of the engine but about which specific version of the Merlin that aircraft was tried with.

 

The Merlin II in the Battle of Britain could barely crack 1000hp. An engine from a Hornet was producing over 2000hp. Put a pair of Hornet engines on a Beaufighter and it would have outperformed the 1600hp Bristol Hercules engines. 1200hp Merlin XXs (or whatever they were exactly) came up 800hp short on a Beaufighter, which given the base power needed to maintain straight and level flight, is most of the excess power that should have been available for climbing or acceleration.

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2 hours ago, Graham Boak said:

 

Tell that to Halifax crews.  It wasn't a great success on the Beaufighter or Wellington, either.  Life is never that simple.

I don't have enough knowledge to refute any of that. But suffice to say the Hercules engined Lancaster wasn't a success either. But we do know that a Merlin engined Lancaster was better than a Hercules engined Halifax. 

Just reading Jamie's comments kind of put it in perspective for me. 

Looking at the Merlin, even to this day it's been developed to a point by the air racing community to unheard of power. It's quite the legacy.

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1 hour ago, bzn20 said:

Could be an aerodynamic reason but can't see that, the Merlin has a smaller cross section

I read somewhere that the intuitive perception that any inline engine has a smaller cross section than a radial is incorrect.

 

If you add in the cross sections of the necessary radiators/cooling intakes etc, needed for an inline, there isn't that much difference.

 

Ken

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2 hours ago, Jamie @ Sovereign Hobbies said:

Rolls Royce, not having the attention available to give the Vulture, worked around the big end bearing failures and heat dissipation problems by reducing the maximum engine RPM. As we all know power is a function of torque x RPM, so that also limited the power. That in turn constrained the Manchester.

 

Rolls Royce were fairly confident they could sort out the Vulture, but they were just too busy making Merlins.

Surely a similar story to that of the Westland Whirlwind - Rolls Royce were too busy with the Merlin to develop the Peregrine to the required standard.

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Hello

Vulture had rows in X configuration and this resulted in large front cross section and considerable air resistance. By comparison, Sabre's cylinders were in H configuration, which produced far less drag. Also, with one engine out Manchester lost half of its power and keeping her straight and level in such condition had been considered quite a feat. IIRC a well-earned DFC had been awarded to a Manchester pilot (do not remember his name, unfortunately) for bringing her back to base on one engine after bombing Berlin. Cheers

Jure

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I believe Napier didn't sort out the Sabre issues until English Electric took them over and applied the proverbial boot up the backside, whereupon it started to perform much better. I've also read that the Vulture engine performed much better in the Tornado's it was fitted to, though this may be down to them being prototypes and therefore more likely to have longer services than those in the Manchesters. 

 

As for the Whirlwinds, the Peregrine engine was, in effect, the end of development of the Kestrel engine and therefore a little bit of a dead end development. I think someone on here mentioned the possibility of Merlins being fitted, but the airframe was unable to take the additional stresses of the heavier engine, which was a shame.

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3 hours ago, Welkin said:

Surely a similar story to that of the Westland Whirlwind - Rolls Royce were too busy with the Merlin to develop the Peregrine to the required standard.

Hi

    Not all the peregrine engines fault with the whirlwind,

     I have a copy of a report that shows, that the engine installation fitting quality needed adjustment, and that the westland air intake design, restricted engine breathing

      when the corrections were made it was to late, and the aircraft was returned to standard configuration

     cheers 

       jerry

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4 minutes ago, charlie_c67 said:

.....

As for the Whirlwinds, the Peregrine engine was, in effect, the end of development of the Kestrel engine and therefore a little bit of a dead end development. I think someone on here mentioned the possibility of Merlins being fitted, but the airframe was unable to take the additional stresses of the heavier engine, which was a shame.

Hi

    The old myth 

    There is a letter from westlands in the PRO/NA dated jan 1941 stating that westlands are now able to offer the whirlwind with merlin XX engines,after sorting the undercarriage retraction issues.

    this was separate from the welkin design.

       cheers

         jerry

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11 hours ago, Flankerman said:

I read somewhere that the intuitive perception that any inline engine has a smaller cross section than a radial is incorrect.

 

If you add in the cross sections of the necessary radiators/cooling intakes etc, needed for an inline, there isn't that much difference.

 

Ken

 

There is no clear answer because every design has different features. Yes, radial engines have a larger cross section of the engine alone, however the effect on drag can be reduced through a good design of the cowling,. And yes, the water radiators required for water cooled engines add to the cross section but again the effect on drag can be reduced through proper design and by exploiting the Meredith effect.

 

 

7 hours ago, charlie_c67 said:

I believe Napier didn't sort out the Sabre issues until English Electric took them over and applied the proverbial boot up the backside, whereupon it started to perform much better. I've also read that the Vulture engine performed much better in the Tornado's it was fitted to, though this may be down to them being prototypes and therefore more likely to have longer services than those in the Manchesters. 

 

As for the Whirlwinds, the Peregrine engine was, in effect, the end of development of the Kestrel engine and therefore a little bit of a dead end development. I think someone on here mentioned the possibility of Merlins being fitted, but the airframe was unable to take the additional stresses of the heavier engine, which was a shame.

 

But was the Sabre actually ever sorted in the way that the Merlin was ? Sure most reliability issues were at some point cured, but IIRC it was always prone to catch fire at the start til the end of the Tempest career

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The Sabre's problems were sorted out when the MAP leaned on Bristol to share their sleeve valve manufacturing technology.  That and a detail approach to reducing vibration such as rubber mounting blocks and the 4-blade prop.

 

To have fitted Merlins to the Whirlwind would have required considerable redesign, which no doubt Westlands were indeed prepared to undertake, and this would have taken considerable time making the resulting aircraft uncompetitive anyway.  It would not have been possible just to drop the engines into the current airframe.  (Maybe for a racer, but not a service type.)  However, there is a long thread on Flypast's Historic Aircraft forum making a very strong case for the Whirlwind's performance problems at altitude being linked to the choice of propellers for the production machine and the then-level of understanding of compressibility effects.  Beyond this, the Whirlwind's main problem is that it was too late for the one battle in which it might have made a difference, and this was linked to Westland's overall weakness of being a small team.  This almost certainly have influenced the AM's approach to any later promises by the company.  Not that Westlands were the only company in this position - the same was equally true for other small companies such as Supermarine.

 

Whereas it is certainly true that the drag (rather less the cross-sectional area) of the inline's cooling system has to be taken into account when comparing inline vs radial, Meredith's prewar study into ducted-flow radiators did much to reduce the effect of this.  As seen on most notably the P-51, but also on the Spitfire and Bf.109.  At this time, designs with radial engines still paid a considerable penalty due to the need for fatter fuselages and inefficient exhaust systems.  However, Kurt Tank demonstrated the way out of these matters with his Fw.190.

 

PS  Plus the later inlines - Sabre, Vulture, perhaps even Eagle? - had large cross-sections anyway.  RR did have the Crecy up its sleeve, but that has to be an unknown quantity.

Edited by Graham Boak
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17 hours ago, JohnT said:

Your post about two engines for the price of one immediately reminded me of the problems with He177.

Like Avro, Heinkel proposed 4-engined versions of the He.177 (He.274 and He.277), although unlike Avro, neither came to anything.

 

Apologies for digressing OT earlier!

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