Rolls Royce Griffon - 1945 magazine article
- Thread starter Shannow
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Tnx
Interesting.
Good find! Impressive technology for the day...
Great article. I am always reminded of how the Mustang was considered a dud aircraft until the Brits replaced the engine with the Merlin, and creating perhaps the best fighter and definitely the best bomber escort airplane of WWII.
That engine is engineered !!. V-12 Aero engines are awesome. P 51 Mustangs are still raced.
The main problem with Rolls Royce engines was the hand tooling required to assemble. Picture a bunch of older guys wearing glasses and dirty aprons busily filing away. "Hmmn ,needs a little off here.Then I'll try the fit after tea.". Add being a prime target for German bombers. The Allison and the Packard engines took the designs and applied modern engineering processes to ensure the parts were built to tolerances that allowed parts to be assembled without so much fitting. Instead of a 100 engines a month, 1000s were produced in the arsenal of democracy.
The main problem with Rolls Royce engines was the hand tooling required to assemble. Picture a bunch of older guys wearing glasses and dirty aprons busily filing away. "Hmmn ,needs a little off here.Then I'll try the fit after tea.". Add being a prime target for German bombers. The Allison and the Packard engines took the designs and applied modern engineering processes to ensure the parts were built to tolerances that allowed parts to be assembled without so much fitting. Instead of a 100 engines a month, 1000s were produced in the arsenal of democracy.
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Did anyone dig into the specs?
2,220 HP
Maximum RPM 2,750
0.992 HP /CuIn
Those are numbers that the OEM automotive world didn't see until the 1960's, and under no circumstances did they achieve them at under 3,000 RPM.
As for the "hand tooling" myth, for starters, if there was any hand tooling, it was done by 19 year old women, not men, during WWII. The UK conscripted to age 45.
2,220 HP
Maximum RPM 2,750
0.992 HP /CuIn
Those are numbers that the OEM automotive world didn't see until the 1960's, and under no circumstances did they achieve them at under 3,000 RPM.
As for the "hand tooling" myth, for starters, if there was any hand tooling, it was done by 19 year old women, not men, during WWII. The UK conscripted to age 45.
There is nothing about a modern engine - aside from computer control and VVT - that an aircraft mechanic from WW! wouldn't understand, the basic layout of the Griffon being much the same as the Eagle engine first produced in 1915.
Hydraulic disc brakes, the self starter, windshield wipers, 4WD, you name it, it was mostly all produced before WW!, or at least working prototypes had been built.
Claud.
Hydraulic disc brakes, the self starter, windshield wipers, 4WD, you name it, it was mostly all produced before WW!, or at least working prototypes had been built.
Claud.
Originally Posted By: Shannow
https://drive.google.com/open?id=1TaTKK_ILhKiPJvct1NnOzwlPvsBY73WM
Thank you for posting this very interesting article on the RR aircraft engine. Truly a work of art. And thank you UK for being our ally through good and not so good times.
https://drive.google.com/open?id=1TaTKK_ILhKiPJvct1NnOzwlPvsBY73WM
Thank you for posting this very interesting article on the RR aircraft engine. Truly a work of art. And thank you UK for being our ally through good and not so good times.
Thanks for posting! Incredible engine.
Originally Posted By: Johnny2Bad
Did anyone dig into the specs?
2,220 HP
Maximum RPM 2,750
Correction... 2,750 is the maximum propeller RPM... the crankshaft RPM
could go as high as 3,700 RPM... Rolls Royce V12 engines employ a
single spur gear reduction of 0.98 ratio to multiply the crankshaft
torque and to lowered the propeller RPM... Propellers are most
effective at subsonic airspeeds 480mph to 512mph any higher and you
risk the blade tips speed going supersonic with deadly shockwaves
producing high drag and related mechanical problems... basically the
more prop noise you hear the less efficient thrust you get...
Its the Merlin but your get the layout
My finger is touching the crank on a blown Griffon Reno Air Races...
480mph was possible by trimming the props diameter for 2008 winner Strega...
Did anyone dig into the specs?
2,220 HP
Maximum RPM 2,750
Correction... 2,750 is the maximum propeller RPM... the crankshaft RPM
could go as high as 3,700 RPM... Rolls Royce V12 engines employ a
single spur gear reduction of 0.98 ratio to multiply the crankshaft
torque and to lowered the propeller RPM... Propellers are most
effective at subsonic airspeeds 480mph to 512mph any higher and you
risk the blade tips speed going supersonic with deadly shockwaves
producing high drag and related mechanical problems... basically the
more prop noise you hear the less efficient thrust you get...
Its the Merlin but your get the layout
My finger is touching the crank on a blown Griffon Reno Air Races...
480mph was possible by trimming the props diameter for 2008 winner Strega...
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Originally Posted By: SonofJoe
A jolly good read from an easier to understand time.
Yes, I treasure my british sourced texts up to around the late 50s...I've read this one cover to cover four times.
https://www.amazon.com/Efficient-Use-Steam-Oliver-Lyle/dp/B0006ARQ7E
Here's another Merlin paper from my archives...(thought I'd go back and find the things I've stashed "for later"
https://drive.google.com/open?id=1TyuwfgQrGmrJeFKRCUZVSempGn6RGfGx
A jolly good read from an easier to understand time.
Yes, I treasure my british sourced texts up to around the late 50s...I've read this one cover to cover four times.
https://www.amazon.com/Efficient-Use-Steam-Oliver-Lyle/dp/B0006ARQ7E
Here's another Merlin paper from my archives...(thought I'd go back and find the things I've stashed "for later"
https://drive.google.com/open?id=1TyuwfgQrGmrJeFKRCUZVSempGn6RGfGx
While in a sharing mood, here's the GEC design for the first of the "big" 500MW units. Ended up being built by Parsons (who became Rolls Royce at one Stage)...these units became the basis for King's North Diddcott, Nanticoke, and the place that taught me to be an engineer (Wallerawang).
https://drive.google.com/open?id=0B72RMQAMdx4iVFFmN2V2OWYyaWluZklPWVRmRjNRTEhxbFJr
This one goes without saying as one of the greatest tomes there is.
https://drive.google.com/open?id=1ed4oWKxeZlmEbbd9gTMTgZA8Pfcr7Rb6
https://drive.google.com/open?id=0B72RMQAMdx4iVFFmN2V2OWYyaWluZklPWVRmRjNRTEhxbFJr
This one goes without saying as one of the greatest tomes there is.
https://drive.google.com/open?id=1ed4oWKxeZlmEbbd9gTMTgZA8Pfcr7Rb6
Originally Posted By: Johnny2Bad
Did anyone dig into the specs?
2,220 HP
Maximum RPM 2,750
0.992 HP /CuIn
Apologies Johnny please disregard my first post... 2,750 is engine RPM with a prop reduction of 0.51... I'll give myself a good talking too...
Did anyone dig into the specs?
2,220 HP
Maximum RPM 2,750
0.992 HP /CuIn
Apologies Johnny please disregard my first post... 2,750 is engine RPM with a prop reduction of 0.51... I'll give myself a good talking too...
Originally Posted By: Shannow
Here's another Merlin paper from my archives...(thought I'd go back and find the things I've stashed "for later"
https://drive.google.com/open?id=1TyuwfgQrGmrJeFKRCUZVSempGn6RGfGx
Thought that some of you might be interested in the bit described in Fig 34, the "photoelastic effect".
Back in the days before complex problems solving computers and CFD...my training we had to be able to do finite element analysis by matrix inversion (I winged that subject seriously)...
We had a couple of photoelastic benches. Light, shining through a polarising filter, through an epoxy model of the object to be tested, and then through another polarising filter.
As a stress was applied to the epoxy component, the refraction would change and there would be a change in polarisation of the light exiting the model, which would show up as a colour band when looked at through the top filters.
The colours would start at the point of the highest stress, change through the range, then start again...complex stuff, you had to coung the number of times that is cycled through.
Here's a couple of images of it, showing the concept of "stress concentrators"
Here's another Merlin paper from my archives...(thought I'd go back and find the things I've stashed "for later"
https://drive.google.com/open?id=1TyuwfgQrGmrJeFKRCUZVSempGn6RGfGx
Thought that some of you might be interested in the bit described in Fig 34, the "photoelastic effect".
Back in the days before complex problems solving computers and CFD...my training we had to be able to do finite element analysis by matrix inversion (I winged that subject seriously)...
We had a couple of photoelastic benches. Light, shining through a polarising filter, through an epoxy model of the object to be tested, and then through another polarising filter.
As a stress was applied to the epoxy component, the refraction would change and there would be a change in polarisation of the light exiting the model, which would show up as a colour band when looked at through the top filters.
The colours would start at the point of the highest stress, change through the range, then start again...complex stuff, you had to coung the number of times that is cycled through.
Here's a couple of images of it, showing the concept of "stress concentrators"
Interesting data comparison...Merlin vs Allison....so close....and yet different
https://www.facebook.com/groups/257529494337013/permalink/1761367523953195/
https://www.facebook.com/groups/257529494337013/permalink/1761367523953195/
Allison versus Rolls Royce
All though both manufactures featured 4 valves per cylinder Rolls
Royce combustion chamber was flat where as Allison sported a modern
pent roof combustion chamber very much like that of our current high
performance motorcycle engines and F1 racing...
Had Allison's engineers been able to put the effort into gear driven
superchargers that Roll Royce did, it might have been a different
story. As it was the V 1710 had more potential than was actually
exploited...
All though both manufactures featured 4 valves per cylinder Rolls
Royce combustion chamber was flat where as Allison sported a modern
pent roof combustion chamber very much like that of our current high
performance motorcycle engines and F1 racing...
Had Allison's engineers been able to put the effort into gear driven
superchargers that Roll Royce did, it might have been a different
story. As it was the V 1710 had more potential than was actually
exploited...
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