davebender
1st Lieutenant
Under historical circumstances the engine would need to be produced overseas as WWII Rolls Royce couldn't even meet demand for the higher priority Merlin Engine.
The "best fighter engine in the world"
- Thread starter wuzak
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Shortround6
Major General
Which Griffons had the short life span and what service were they in?
Most fighters operating from forward strips in Normandy/France had short lived engines due to sand/dirt ingestion, not defective design. Bomber engines usually last longer than fighter engines, and transport engines even longer. Shackleton engines seemed to do OK for longevity in post war use.
Most fighters operating from forward strips in Normandy/France had short lived engines due to sand/dirt ingestion, not defective design. Bomber engines usually last longer than fighter engines, and transport engines even longer. Shackleton engines seemed to do OK for longevity in post war use.
Shortround6
Major General
Nice try at shifting the argument, You seemed to be claiming the Griffon was not built in as large a numbers as the DB 603 and Jumo 213. OK, it wasn't but why?
In part because those "higher priority Merlin Engine" s could do the job better than the DB 605 and Jumo 211 engines and didn't NEED to be replaced in Production as much as the German engines needed to be.
Merlin 85 used in Avro Lincoln bomber was good for 1635hp for take-off and 1705hp at 5750 ft and 1580hp at 16,000ft. using 100/130 fuel. The take-off power is 115hp below the German engines but the power at altitude is a lot closer, 1620hp at 18,700ft for the more common DB 603s and 1600hp at 18,000ft for a Jumo 211A. Merlin was about 350lbs lighter.
Griffon was even better but as there was less NEED the priorities didn't need to change. AS I said, if for some reason the Merlin in 1943-44 had run into a wall and couldn't be developed as it was, THE PRIORITIES would have CHANGED and one or more factories changed over to Griffons.
Germans were forced to change over because, now matter how HIGH a priority the DB 605 or Jumo 211 had they couldn't actually do the job needed and had to be replaced.
Shortround6
Major General
Getting back to the question the Griffon 61 in 1942 on test, It certainly looked like the best fighter engine known to the British at the time. 100/150 fuel not being available or at least not in a production form.
With 2035hp at 7000ft and 1820hp at 21,000ft (at 18lbs on 100/130) it can equal a two stage R-2800 down low and have several hundred more hp at high altitude. It is 400lbs lighter than the R-2800 which helps offset the weight of the radiator and coolant. It should be easier to streamline.
Sabre IIa may be on test stands. It doesn't show up in service aircraft until 1943. While it easily out powers the Griffon 61 down low it's 1880hp at 15,250ft doesn't look so good for medium to hi altitude work. The extra 400lbs doesn't look so good either.
With 2035hp at 7000ft and 1820hp at 21,000ft (at 18lbs on 100/130) it can equal a two stage R-2800 down low and have several hundred more hp at high altitude. It is 400lbs lighter than the R-2800 which helps offset the weight of the radiator and coolant. It should be easier to streamline.
Sabre IIa may be on test stands. It doesn't show up in service aircraft until 1943. While it easily out powers the Griffon 61 down low it's 1880hp at 15,250ft doesn't look so good for medium to hi altitude work. The extra 400lbs doesn't look so good either.
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- Thread starter
- #25
wuzak
Captain
Compare the Griffon to the DB603 - lighter, more comapct and more powerful.
RPM development seems to be the problem with the Griffon.
Two stage Griffon is under 2000lbs. The two stage R-2800-8 (F4U) and -10 (F6F) weigh 2480lbs, which is close to 500lbs heavier than the Griffon 65. Those R-2800s are rated at 1650hp @ 22,000ft, so about 150hp or so down on the Griffon at that altitude.
One wonders what would have happened if Republic tried a Griffon in the XP47H(?) instead of the IV-2220. Coupled with a turbo the single stage Griffon could have been used, saving a further 100-200lbs, and its suercharger geared LS (probably sea level)/MS instead of MS/FS.
RPM development seems to be the problem with the Griffon.
Two stage Griffon is under 2000lbs. The two stage R-2800-8 (F4U) and -10 (F6F) weigh 2480lbs, which is close to 500lbs heavier than the Griffon 65. Those R-2800s are rated at 1650hp @ 22,000ft, so about 150hp or so down on the Griffon at that altitude.
One wonders what would have happened if Republic tried a Griffon in the XP47H(?) instead of the IV-2220. Coupled with a turbo the single stage Griffon could have been used, saving a further 100-200lbs, and its suercharger geared LS (probably sea level)/MS instead of MS/FS.
Which Griffon and which DB 603... is the single stage Griffon, or the two stage one, is it an early DB 603A or a late DB 603E/L/LA/N? How much fuel do they consume, how much fuel needs to be carried to get the same range in the same aircraft, what it included in their weight (props, supercharger, cooling and oil systems, supercharger carburrator intercooler included - or just a bare engine block? How are dimension measurements made - do they include the propellor shaft, aux. devices sticking out, or is it just the engine block (which defines built-in dimensions)? How does their power curve looks like?
It is not very simple to give a correct answer IMHO.
Shortround6
Major General
The DB 603 is about the weight of a 2 stage Griffon but only about as powerful as a single stage Griffon.
I don't believe there was much problem with the Griffon RPM was there? While it's peak rpm of 2750 was lower than the Merlin in's longer stroke meant the piston speed was higher. Higher RPM might have meant a heavier engine or a shorter overhaul life or both ( short life of Griffons operating from temporary forward airstrips will be ignored unless accompanied by data of life in other settings/operating regimes) .
You are correct about the weight of the Griffon 65, I was going by the weight of the Griffon 69 and sometimes different sources have a different definition of "dry" weight, Certain accessories included or not.
I don't believe there was much problem with the Griffon RPM was there? While it's peak rpm of 2750 was lower than the Merlin in's longer stroke meant the piston speed was higher. Higher RPM might have meant a heavier engine or a shorter overhaul life or both ( short life of Griffons operating from temporary forward airstrips will be ignored unless accompanied by data of life in other settings/operating regimes) .
You are correct about the weight of the Griffon 65, I was going by the weight of the Griffon 69 and sometimes different sources have a different definition of "dry" weight, Certain accessories included or not.
Shortround6
Major General
Fair enough, but to simplify things and keep some sense of reality which of these DB 603 engines actually saw service use in squadron numbers ( say at least 12 aircraft on strength at one time?) otherwise the allied fans can bring in late model Griffons like the two stage, 3 speed Griffon 130.
Going by Wiki ( correction more than welcome) this limits us to the DB 603A, AA, E, and possibly the "G" production canceled but at least not listed as a prototype.
Power for the "A" is listed at 1750hp/sea level/1.4 ata/2700rpm and 1620hp/18,700ft/1.4ata/2700rpm for take-off and emergency.
Power for the "E" is listed at 1800hp/sea level/1.48 ata/2700rpm and 1550hp/23,00ft/1.48ata/2700rpm for take-off and emergency.
Power for the "AA" is listed at 1670hp/sea level/1.4ata/2700rpm and 1450hp/24,000ft/1.4ata/2700rpm for take-off and emergency.
Power for the "G" is listed at 1900hp/sea level/-.-ata/2700rpm and 1560hp/24,300ft/-.-ata/2700rpm for take-off and emergency.
Power figures are from the 1946 edition of "Jane's" and may need updating.
E and AA were noted as having superchargers of increase diameter compared to the A and the G was supposed to have had increased compression.
Dry weights of engines almost always include the attached superchargers and carburetors/injection system. Turbos being mounted remote are not included as are many items that would vary from installation to installation, like exhaust stubs/pipes, certain pumps, starters, generators and so on.
Dry weight is for a rather bare engine but hardly a bare engine block. (try buying a bare car engine block and see what you get, or even a "short block")
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Shortround6
Major General
Not the ones we are talking about, if ever. But the cutting out when under negative "G" had been solved before the Griffon went into service. A number of Griffons used "injection carburetors" or fuel injection into the eye of the supercharger.
davebender
1st Lieutenant
Are you comparing mass production engines from the same time frame?
davparlr
Senior Master Sergeant
Here is a comparison of cooling systems according to data in "America's Hundred Thousand" of liquid cooled US fighters showing assigned weight and rough power levels. I think this can give an idea of off-setting weight of liquid cooled engines verses air cooled. I believe coolant system weight includes coolant.
P-38J Weight/engine-532 lbs, power/engine – 1400-1600 hp. (note: complex cooling system)
P-39D-2 323 lbs, 1100-1400 hp. (note: tightly coupled cooling system)
P-40F 306lbs, 1200-1300 hp. (note: tightly coupled cooling system)
P-51B 663lbs, 1400-1700 hp. (note: complex cooling system)
I think it is reasonable to assume coolant system weight for a 2000 hp+ engine would be around 500 lbs. Also, I think the logistics trail of a separate complex subsystem such as a liquid cooling system with fluid would be significant, something the Navy would be concerned about.
1939-41: R-2800
1942-43: R-2800
1944-45: R-2800
You may argue about availability in 1939-40.
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All Lancasters used Packard built Merlins.
KiwiBiggles
Senior Airman
No. Mk I used Rolls Royce, Mk III used Packard, and Mk II used Bristol Hercules.
fastmongrel
1st Sergeant
Amazing how the first Lancaster managed to fly 8 months before the first Packard V1650 was built.
Shortround6
Major General
Dang, another good myth wiped out by facts.
- Thread starter
- #39
wuzak
Captain
And Lancasters were know to have flown with engines sourced from different factories in the UK and from Packard at the same time!
fastmongrel
1st Sergeant
To build Rover Meteor tank engines used parts from life expired or damaged Merlins and V1650s were used interchangeably as long as they passed inspection. Crankshafts were always in short supply and obviously aircraft engines got priority so used or new slightly out of specification cranks could be used in Meteors where they had an easier life due to no Supercharger.
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