Shortround6
Major General
What new "technology" did Daimler-Benz use or develop in the DB 605? New materials in the bearings? a new type of bearing? New coolant? New oil?
WI The Rolls Royce Vulture is a success
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Edgar Brooks
Senior Airman
It was the succession of con-rod bolt failures, in service, plus the decision to go for 4 Merlins in the Lancaster, that did for the Vulture; the problems were nowhere near being solved (according to Rubbra, that is.)
Edgar
Edgar
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- #23
fastmongrel
1st Sergeant
From the bits and pieces I have read about the Vulture (not a great deal out there) it seems that the RR engineers had worked out the problems, had a solution and werent too far off getting the engine working at full power. According to Bill Gunston World Aero Engines 2nd edition p143 in march 41 the Vulture was rated for takeoff at 2,100 hp using 100 octane and 9lbs of boost (no rpm given).
However the Manchester was to be cancelled in favour of the Lancaster and Ernest Hives cancelled any further development work at the same time deciding his engineers could be working on other engines with a future. In fact Hives had wanted to cancel work on anything other than the Merlin and Griffon in Aug 1940.
I might be taking a leap but it seems as if the con rod failures and associated maximum rpm restrictions might have been solved by march 41.
RR had another X engine the Rolls-Royce Exe - Wikipedia, the free encyclopedia which seems to have been totally trouble free so RR must have known something about X engines.
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davebender
1st Lieutenant
Sounds like a sensible solution to me. IMO the Luftwaffe made a serious mistake by not pushing development and production of the DB603 engine. The RAF made a a similiar mistake by not pushing development of the RR Griffon engine. Instead both nations poured a lot of money into the development of 24 cylinder monster motors.
wuzak
Captain
Monster Motors
The DB603 may have been suitable to replace the DB601 or the DB605, but not the DB604. The DB604 was more powerful (except for the later 2 stage DB603N), only slightly larger in capacity and a few hundred pounds heavier than the DB603.
The DB604 was also as powerful as the DB606, but significantly lighter in weight. The DB606 was coupled DB601s, they also built coupled DB605s (the 610) and DB603s (DB613). They were also developing the DB609 (the V16 version of the DB603) which was heavier, larger in capacity and had the same power as the DB604, and was cancelled a year later than the DB604 was.
Basically DB had a lot more going on than RR, and if they could have streamlined things a bit then they may have been able to continue with the DB604.
The DB604 could potentially have been fitted to most of the aircraft which the DB603 was, and aircraft like the He219 could have benfitted. The DB604 would probably also be fitted to the same bulkhead as the BMW 801 - which would have enabled a DB604 powered Fw190. It may have also been the best engine choice for the Me264. It may even have worked well in the He177.
I have not seen any indication as to whether the DB604 was reliable or not, or for what reason it was cancelled.
As far as RR goes, I wonder if the Griffon was not able to be fitted to the Spitfire if that would have been cancelled. The Griffon was requested by the FAA, but we know that they usually took a back seat to the RAF.
wuzak
Captain
The Vulture was very much detuned to the power it was rated at. The Vulture V was rated at 1780hp @ 2850rpm with +6psi boost according to Rolls-Royce Vulture - Wikipedia, the free encyclopedia. The Merlin went from +6psi boost and 1030hp to +12psi boost and 1300hp just by changing the supercharger gearing and using the new PN100 fuel (5 minutes only). Later Merlins with some more modifications were cleared for +18psi boost in emergencies.
The point being, that the Vulture basically had the same combustion chamber shape as the Merlin, so the added boost would not be a problem from a detonation or combustion point of view. The Vulture was designed for more power than it was giving, so the components, largely, were strong enough for the added duty.
The only question is how does the big end of the master rod cope. And depending who you read, that was solved, or nearly so, at the time of cancellation.
I again, repeat that RRHT confirmed to me that the Vulture ran on test at 2500hp several times. IIRC Lumsden states that one engine was run to 3000hp, but RRHT could not confirm that.
wuzak
Captain
The Exe was a small capacity engine - similar in capacity to the Kestrel/Peregrine, but with 24 cylinders. The later Pennine also used master and slave rods, was just under 2800 cubic inches and was rated at around 2800hp @ 3500rpm. That only operated on the test bench, unfortunately, so we can't be sure what issues it may have had. I am sure that the lessons learned with the Vulture were applied to teh Pennine, though.
pbfoot
1st Lieutenant
I read where they didn't use silver in the main bearings and the oil passages were to small caused much of the grief it was a poor engine in a worse aircraft
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- #29
fastmongrel
1st Sergeant
Manchester wasnt a worse aircraft after all it was basically the same fuselage that became the Lancaster. The squadrons had a lot of problems but they all seem to have been caused by engines and not enough power for 1 engine out flying. Fix the Vultures reliability problems let it run at the designed rpm and boost and the Manchesters problems mostly go away.
pbfoot
1st Lieutenant
Britain gave up on the manchester because it was crap from a previous thread
http://www.ww2aircraft.net/forum/av...n-give-up-avro-manchester-bomber-28512-4.html
quoted from Mike Lewis DFC CD one of the first Manchester pilots 207 Sqn quoting about Manchester 1A "the mid upper turret on the Manchester never did function properly. When rotated it set up a disconcerting vibration in the airframe. The AirMinistry finally circulated aletter permitting the squadrons and Avro to remove the turret if desired . I always had the mid upper removed from my aircraft removed from my aircraft giving me an extra 10 mph and improving single engine performance immenesly `` Mike Lewis did 2 tours on Manchesters
1) the heated flying suits had individual outlets for each piece of clothing in other words each glove had its own receptacle
2) to rectify this they pumped hat air from oil cooler into aircraft but with only one outlet at the radio operators position it was so hot the RO couldn't remain in position so it was blocked off by crews
3)the feathering solinoid for the prop was faulty and frequently changed the pitch of the prop witthout prompts
4)the high pressure hydraulic system was junk with no "olives" on the joints which would frequently blow , paper washers on the engineers panel would also fail
5) Getting bombays open " The designers had thought of this one. Holes bored in the lower side of the bombay actuatorswere were filled with plugs connected to a steel cable running to the front of the bombbayinside the nose section. pulling this wirewthdrew the plugs from the hydraulic jacksand the oil drained by gravity. The bombays sagged enoug for the slipstream to catch them and whip them fully open. We would drop our bombs but would have to fly remainder of mission with bomb doors open
6) although designed to carry a 4000lb bomb the bomb had yet to be designed and the bomb was to big so they cut open the bombay and the bomb doors were modified with bungee cords so the doors would close
7) This pilot reported that one would get exhausted after flying 3 circuits
davebender
1st Lieutenant
Most of those problems have little to do with Manchester engines. They needed to be fixed for the Lancaster also.
Edgar Brooks
Senior Airman
The RAF had nothing, whatsoever, to do with engine development; it was all down to the manufacturers, since, being privately owned, if the engine wasn't good enough, the Air Ministry wouldn't buy it.
Rolls-Royce, at first, couldn't see a use for the Griffon, although the first one was tested in 1933; by 1939 they'd changed their minds, and the Griffon I was running in the Experimental dept. Far from the FAA taking a back seat to the RAF, they got the Griffon, first, in the Firefly; however Rolls-royce were not happy with the layout, so redesigned it into the Griffon III, which went into the Spitfire XII.
Camm wanted to produce a Griffon-powered Hurricane, but the necessary redesign was so complex, he was told to forget it, and concentrate on the Typhoon and Tempest.
Edgar
Shortround6
Major General
Even if the Vulture was fixed, or could be fixed, Twin engine heavy bombers were thought to be a bad idea. Losing one engine doesn't just drop the power in half, it sets up an asymmetrical power situation. A number of 4 engine bombers made it home on two engines, the real problems occurred if they lost both engines on the same side. The aileron and rudder trim needed to keep the plane level and pointed straight, or least to fly a straight course severely increased the drag over an engine out on each side. This was often the difference between making back or not.
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fastmongrel
1st Sergeant
Not saying Mike Lewis is wrong but name me one aircraft that was perfect in its initail version. After all the Manchester Mk IA was pretty much an early Lancaster Mk I apart from the wings, engines and turrets. I have heard rumours the Lanc was quite useful though I never trust wikipedia
pbfoot
1st Lieutenant
The feathering of props and random times would be somewhat unsettling , and wings and engines would certainly be high amongst top things to worry about , the fuelage amongst the least and the Lanc wasn't without faults ask pilots anout the shimmy from the tail wheelNot saying Mike Lewis is wrong but name me one aircraft that was perfect in its initail version. After all the Manchester Mk IA was pretty much an early Lancaster Mk I apart from the wings, engines and turrets. I have heard rumours the Lanc was quite useful though I never trust wikipedia
wuzak
Captain
The Air Ministry would contract with the engine suppliers to develop engines according to some requirements. Occasionally engine manufacturers would make a private venture engine (ie like the PV12, Fairey's attempts at getting in the engine business). Without Air Ministry funding/backing it was difficult to develop an engine. In the case of the Vulture the Air Ministry had funded and backed it since 1935, and it was not their decision to cancel it - that came from Rolls Royce, and was ratified by the Air Ministry. The reason wasn't that the Vulture's problems were unsolvable, but a resource allocation issue. (At the same time RR were working on the Crecy under orders from the Air Ministry, though Hives wanted to stop that as well.)
The 1933 Griffon was a detuned version of the R, which was a hotted up version of the Buzzard. As such its basis was old and would have limited development potential by WW2.
The 1939 Griffon was a response to a request from the FAA for a more powerful/larger engine than the Merlin. It had nothing in common with the Buzzard/R and the 1933 Griffon except bore and stroke. During the early development a member of the Air Ministry suggested fitting a Griffon to the Spitfire. Joe Smith of Supermarines drew up a proposal around that, which was taken to Rolls Royce. For the engine to fit in the Spitfire some features needed to be redesigned, which resulted in a more compact layout. It was the need to fit the Griffon in the Spitfire which led to the Griffon being redesigned, this mostly involving the layout of the accesories.
The Spitfire MkIV flew 1 month before the Firefly I (November 27 vs December 22 1941), and the Spitfire MkXII enetered service in October 1942, while the production Firefly I was delivered in March 1943, but did not become operational until July 1943. It woudl appear that slightly more Griffon Spitfires were built durng WW2 than Fireflies.
davebender
1st Lieutenant
If you have only one major customer then that customer has a great deal of influence over your business. Otherwise the RAF will purchase engines elsewhere.
pbfoot
1st Lieutenant
What WW2 aircraft was as bad as the Manchester , the reason the Lanc tail shimmied is that iy lacked a locking tail wheel which was common on Brit A/C it saved money , as did other basic items like deicing equipmemt . IIRC there was an issue on prop feathering possibly a lack of a resovoir
wuzak
Captain
This is true. The original concept for twin engined bombers like the Manchester (it was not considered a heavy bomber, but a medium bomber - the Short Stirling and Supermarine 317 were considered heavies) was that the use of two powerful engines would be more efficient due to less drag than four smaller engines. Which is true, but it didn't work out that way - partly because of the problems with the Vulture, and it not being powerful enough for single engine duty.
Compare with the Mosquito. A much smaller and lighter twin, which didn't give much away in power. Single engine performance was more than acceptable.
George Volkert wrote a document titledA Memorandum on Bombing Policy and its Influence on design in 1937, which included specifications for a high speed unarmed bomber based on the P.13/36 requirement (which led to the Manchester and Halifax). It was a twin Vulture aircraft with a predicted maximum speed of 380mph, and a bomb load maximum of 7000lbs. I wonder how it would have fared had it continued to the prototype stage.
