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#201 gruntguru

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Posted 14 January 2014 - 07:20

Or, more correctly, the Sabre didn't need as much boosting, since it could out-power the equivalent capacity R-R Griffon,

( & the Griffon had to be backed off from +25lbs due to premature crankshaft bearing failure).

 

The Sabre was strong enough to hack full throttle for take-off..

When really boosted up on test, the Sabre made big power, accordingly.

 

Wartime Sabres were boost-limited due to propeller capacity,

they were cleared for +13lb once Rotol ( coincidentally Rotol was owned by R-R)

props finally became available, after much pressure was applied due to the V1

assault on London in `44.

 

JAW. I am a long time fan of the Sabre. IMHO with a two stage supercharger (and a little less CR) it would have been the ultimate all-altitude fighter engine - a real Griffon killer.



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#202 gruntguru

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Posted 14 January 2014 - 07:31

Would a 1500hp 1 lap wonder F1 turbo pass a 100 hour type-test at those out-puts?

Of course not - and that was not the point I was making.

 

OTOH. 1500 bhp from 1.5 litres = 36,000 bhp from 36 litres. Perhaps one could de-tune the design a bit and still make 5,000+ reliably?



#203 JAW

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Posted 14 January 2014 - 07:35

For sure, it does seem clear from this distance that both Hawker & Napier were stymied by the R-R dirty tricks brigade..

 

Just compare the performance of the Hawker Fury prototype LA 610 which flew with all 3 big British mills..

 

Ranking.. 1. Sabre; 2, Centaurus; 3, Griffon..

 

In fact the Centaurus should've been the power-plant for the Shackleton,

& later the Napier Nomad -  providing another example of R-R  'political' power.



#204 JAW

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Posted 14 January 2014 - 07:38

The design that makes 1,500hp would need considerable boosting, to make 5,000hp..

Doubt it could do it reliably, & certain it couldn't do it & get flight certified..



#205 Ron B.

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Posted 14 January 2014 - 07:42

Interesting find..

 

The Allies didn't use the German DFI system,

but post-war investigations by Bristol for their sleeve valve radials showed it held some promise..

 

Counter-wise the Germans didn't use turbos, or high supercharger pressures either,

& both largely due to technical/metallurgical reasons.. 

 The English knew all about the bosch MFi from the beginning and a read of Spitfire history tell us that RAF did all sorts of things to make the Merlin's Carburetor work in a dive. The Luftwaffe pilots simply had to go into a full dive to escape attack from the spitfire.

 Also i must correct you on  one thing  ;)  The DB  603 aircraft engine was supercharged . And a mighty piece of gear it was too, even powering the still Born Mercedes T80 Land speed car .

  • DB 603AA DB 603A with an improved supercharger, rated altitude of 7.3 km, B4 fuel
Power (take-off): 1670 PS (1647 hp, 1228 kW) at 2700 rpm at sea level Combat power: 1580 PS (1558 hp, 1162 kW) at 2500 rpm at sea level

I have also worked on Sleeve valve engines, Knights principle was invented at a time of pioneering efforts in the automotive world to get over problems with poppet valves such as burning seats etc etc. The sleeves themselves and actuating links make for a lot of unneeded complexity and mass. getting those sleeves to fit properly takes a lot skill and large hammer. . High spots in the sleeve are hammered down in order to make the sleeve move smoothly... Not something you want to do on a combat engine too often.  :rotfl:

The Bosch MFi isn't complicated once the principles are understood and the 200Psi injection pressure makes for almost perfect atomisation . I am biased though, my 1969 Mercedes 300SEL 6.3 uses it most effectively . 

I wouldn't want  electronic fuel engine management on a light aircraft  jet airliners don't fit in this discussion ) neither do most of the regulatory organs around the world . The reason piston engined air craft run two mags is because it has to be fail safe  .. the last thing you want to hear while flying is ...silence. 

 

 

I have also seen a Bristol fighter flying low many years ago. The Sleeve valve engine is incredibly quiet ,hence the nickname of "whispering death" ,only the sound of prop giving the game away as the planes attacked the enemy on the ground.



#206 Wuzak

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Posted 14 January 2014 - 07:49

For sure, it does seem clear from this distance that both Hawker & Napier were stymied by the R-R dirty tricks brigade..
 
Just compare the performance of the Hawker Fury prototype LA 610 which flew with all 3 big British mills..
 
Ranking.. 1. Sabre; 2, Centaurus; 3, Griffon..
 
In fact the Centaurus should've been the power-plant for the Shackleton,
& later the Napier Nomad -  providing another example of R-R  'political' power.


Just look at the radiator that the Griffon was saddled with. The Sabre Fury had leading edge radiators, which on the Tempest I prototype proved superior to the production chin radiator.

The Fury, like the Tempest, was developed with the Centaurus in mind. Thus, it was rather a large fuselage, and the advantages of the Griffon were completely lost.

Re the Nomad - that was dumped because it was going to be past its use by date long before it could have been in service. The Shackleton was designed with the Griffon, and maybe the Centaurus was considered, but the Nomad was long way off.

No conspiracy here/

#207 JAW

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Posted 14 January 2014 - 08:00

Ah,  no Wuzak, Sidney Camm & R-R did not exactly see eye-to-eye, & he didn't really like radials in his fighters either..

The Griffon certainly lost out on a power/performance basis in Hawker fighters..

 

Hawker were basically forced to use the Centaurus when the RAF got jet-bent, & cancelled any new recip fighters..

But the final & best performing production Tempests were the Sabre powered F6s..

 

The Shackleton stayed in service 'til when? - a nice little earner for R-R along with Meteor tank mills..

 

You might be a hard-on R-R fan, but the evidence shows their schemes for what they were..



#208 Wuzak

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Posted 14 January 2014 - 08:18

Back to 1st principles time perhaps..
 
B.M.E.P. is the fundamental figure..
 
& made by high pressures in big cylinders at low revs, or small cylinders at high revs..
 
Look again at the power/weight & power/capacity ratio of that Sabre,
it offered 3,500hp ( also at 36ltr capacity) for take-off.
 
Would a 1500hp 1 lap wonder F1 turbo pass a 100 hour type-test at those out-puts?
 
Cant have DNFs - too frequently - in aircraft service you know.
 
Perhaps a look at those off-shore boat-racing Lambo 6ltr V-12s might be worthwhile..


Of course not - and that was not the point I was making.
 
OTOH. 1500 bhp from 1.5 litres = 36,000 bhp from 36 litres. Perhaps one could de-tune the design a bit and still make 5,000+ reliably?


Neither did the Sabre pass a 100 type test at that rating. The type test involved running at various operating modes (take-off, weak mixture cruise, maximum cruise, 1 hour, combat, etc). The rating of 3500hp was for take-off, othewise its maximum was just over 3000hp, and both of those were for no more than 5 minutes.

In BMEP terms, the Sabre was no better than the Griffon.

The Sabre may have been more powerful than the Griffon, but it weighed 25% more and 30% more frontal area.

#209 Wuzak

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Posted 14 January 2014 - 08:20

Ah,  no Wuzak, Sidney Camm & R-R did not exactly see eye-to-eye, & he didn't really like radials in his fighters either..
The Griffon certainly lost out on a power/performance basis in Hawker fighters..
 
Hawker were basically forced to use the Centaurus when the RAF got jet-bent, & cancelled any new recip fighters..
But the final & best performing production Tempests were the Sabre powered F6s..
 
The Shackleton stayed in service 'til when? - a nice little earner for R-R along with Meteor tank mills..
 
You might be a hard-on R-R fan, but the evidence shows their schemes for what they were..


How big an earner was it mate? Were they building new engines all the time? Last Griffon was built in 1955. And by then, only in small numbers.

#210 Wuzak

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Posted 14 January 2014 - 08:30

Ah,  no Wuzak, Sidney Camm & R-R did not exactly see eye-to-eye, & he didn't really like radials in his fighters either..
The Griffon certainly lost out on a power/performance basis in Hawker fighters..


Since when?

The Hurricane was Rolls-Royce powered. The Tornado was Rolls-Royce powered, and flew 6 months before the Typhoon did (with a hand built engine mind). The Tornado was trialed with the Centaurus in 1940 or 1941, and the Tempest was, from the outset, intended to use the Centaurus at some stage. Like the Sabre, the Centaurus had a troubled development.

Camm also proposed Merlin 61 and Griffon powered Hurricanes and claimed rather startling performance figures. The MAP laughed at him.

Still, he managed to procure the Merlin XX for the Hurricane, when they would have been better going into the Spitfire III.


Hawker were basically forced to use the Centaurus when the RAF got jet-bent, & cancelled any new recip fighters..


As above - the Centaurus was always in teh frame for the Tempest and Fury.


But the final & best performing production Tempests were the Sabre powered F6s..


In 1947 maybe. I recall having this discussion in another forum.


You might be a hard-on R-R fan, but the evidence shows their schemes for what they were..


Fantastic engine developers?

#211 Wuzak

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Posted 14 January 2014 - 08:37

The Shackleton stayed in service 'til when? - a nice little earner for R-R along with Meteor tank mills..


Rolls-Royce didn't make any Meteor engines after 1942, and only became responsible for supplying spare parts in 1964.

Rover built the Meteor engine after swapping that business for the jet engine.

#212 gruntguru

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Posted 14 January 2014 - 08:40

Of course not - and that was not the point I was making.

 

OTOH. 1500 bhp from 1.5 litres = 36,000 bhp from 36 litres. Perhaps one could de-tune the design a bit and still make 5,000+ reliably?

 

 

The design that makes 1,500hp would need considerable boosting, to make 5,000hp..

Doubt it could do it reliably, & certain it couldn't do it & get flight certified..

 

Boosting????

 

Bolt 24 of them together to make 36,000 hp from 36 litres, then de-tune to 5,000 hp. It will run all day at that output. You could even take the turbos off.


Edited by gruntguru, 14 January 2014 - 08:44.


#213 JAW

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Posted 14 January 2014 - 08:41

Well Wuzak, it seems your 'recall' is apparently not as lively as your imagination..

 

From the same source as those Sabre figures,

'Aircraft Engines of the World' P.185 has figures for a 2-stage 2-speed Griffon..

 

Not as impressive, in fact as the Sabre though..

 

Only - 1,935hp for take off, (from a B.M.E.P. significantly lower than the Sabre's ,too)..

& the Griffon gave inferior power/weight, power/unit capacity & S.F.C. to boot..

 

R-R were "Fantastic" as in 'taking care of business', but rather over-rated/inadequate as engine developers

since their Sabre equivalents were, effectively - failures..

.. Vulture & Eagle 2..


Edited by JAW, 14 January 2014 - 09:19.


#214 JAW

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Posted 14 January 2014 - 08:43

Bolt them F1 mills together en-bloc.. yeah, right..



#215 JAW

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Posted 14 January 2014 - 08:46

Meteor tank engines were often built from re-cycled - reduced to spares- Merlin engines..



#216 JAW

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Posted 14 January 2014 - 08:58

Ron B - the Knight Sleeve valve system is not the type used in the British aero-engines, they used the B-McC single-sleeve.

 

& any aero-engine fitter using the hammer - as you described - would likely be arrested on a charge of sabotage..

 

All high-performance WW2 aero-engines were supercharged, & the Germans did use some sophisticated fluid drive types..

 

But not turbos, in general service use, unlike the thousands in the USAAF service, & both fighter & multi-engine hi-altitude use..



#217 JAW

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Posted 14 January 2014 - 09:08

Wuzak, look. mate.. AFAIR, S. Camm basically accused R-R of withholding supercharger tech from Napier,

-so the Griffon Spit got the high altitude gig.

 

& later withholding the Rotol props from the Tempest,

- so the high-boost R-Rs could look a bit more competitive as V1 interceptors..

 

Griffons were profitably supported by R-R for the RAF Shackletons for decades..

 

If it wasn't for Stanley Hooker's good boost work, the Merlin would've been pretty ordinary..

 

& ironically, the Vulture powered Tornado ran on & on reliably, it was the brutal Manchester bomber slog that killed them..



#218 JAW

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Posted 14 January 2014 - 10:08

Wuzak, I checked Mason's 'The British Fighter Since 1915' & on P.315 re the Centaurus powered Tempest..

 

"This proposal was made by Camm's staff as a result of experience gained in 1942 with the Centaurus Tornado,

rather than any liking of radial engines by the great designer himself"

 

Mason also reports that when the Tempest Mk V prototype was fitted with the same higher altitude capable

Sabre IV engine as the leading-edge radiator equipped Mk I, it

"achieved a speed of 459 mph at 24,900ft, fully loaded" .. or ~10mph slower with the regular chin radiator..

 

The prototype Mk 6 ( 1st flown on 9 May 1944) - on test  "at Boscombe Down revealed a maximum speed of 462mph at 19,800ft"

-rather better figures than the Centaurus powered Mk 2 could achieve..



#219 Wuzak

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Posted 14 January 2014 - 11:11

Well Wuzak, it seems your 'recall' is apparently not as lively as your imagination..
 
From the same source as those Sabre figures,
'Aircraft Engines of the World' P.185 has figures for a 2-stage 2-speed Griffon..
 
Not as impressive, in fact as the Sabre though..
 
Only - 1,935hp for take off, (from a B.M.E.P. significantly lower than the Sabre's ,too)..
& the Griffon gave inferior power/weight, power/unit capacity & S.F.C. to boot..
 
R-R were "Fantastic" as in 'taking care of business', but rather over-rated/inadequate as engine developers
since their Sabre equivalents were, effectively - failures..
.. Vulture & Eagle 2..


Did you actually calculate the BMEP?

The Griffon 65 with +18psi boost was good for "over" 2000hp @ 2750rpm for a BMEP of 1744kPa.
The Sabre V, which barely made the war, gave 2600hp @ 3850rpm for a BMEP of 1648kPa.

http://www.wwiiaircr...yce_Griffon.pdf
http://www.wwiiaircr...apier_Sabre.pdf

Note that the Sabre VII didn't go into production until after WW2. To get 3500hp it needed ADI. 3500hp @ 3850rpm gives a BMEP of 2219kPa.
The Griffon 100 series, also a post war engine, was able to get 2420hp @ 2750rpm without ADI. That is a BMEP of 2147kPa.
The Griffon 57, which is similar to the Sabre in being a "low altitude engine", was able to get 2500hp @ 2750rpm with ADI, for a BMEP of 2218kPa.

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#220 Wuzak

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Posted 14 January 2014 - 11:30

Wuzak, look. mate.. AFAIR, S. Camm basically accused R-R of withholding supercharger tech from Napier,
-so the Griffon Spit got the high altitude gig.


And you have evidence of this?

In any case, the only ones who prevented RR supercharger tech from reaching Napiers were Napiers themselves.

It goes like this - Napiers start building a very advanced engine in substandard facilities, and struggled to make a reliable product. Napiers were going under, so the MAP asked RR to take over. The Napier board blocked that, so Napier was sold to English Electric instead. EE's first task was to make the Sabre reliable - so they dumped all manner of side projects (like 3 speed 2 stage superchargers) to concentrate on getting production right.

To that end Bristol were ordered to help Napier with sleeve production, and a pair of Sundstrand grinders were diverted from Pratt & Whitney to help with production.



& later withholding the Rotol props from the Tempest,
- so the high-boost R-Rs could look a bit more competitive as V1 interceptors..


Rotol was joint owned by Rolls-Royce and Bristol. Are you accusing Bristol too?

There was de Havilland, licence built Hamilton Standard, propellers which Hawkers could use. But I very much doubt that any props were withheld from Napier's use.



Griffons were profitably supported by R-R for the RAF Shackletons for decades..


I doubt that it was very profitable.


If it wasn't for Stanley Hooker's good boost work, the Merlin would've been pretty ordinary..


Well, how lucky was it for Rolls-Royce that they sought out and hired an aerodynamicist and mathematician to help develop their superchargers? What are the odds that such a move would yield improved superchargers?


& ironically, the Vulture powered Tornado ran on & on reliably, it was the brutal Manchester bomber slog that killed them..


The Vulture was an interesting engine. It had issues, no doubt, and Rolls-Royce were working through them. But the war came, and priority had to be given - the Merlin was powering several aircraft types, and most importantly the Spitfire and Hurricane, while the Vulture was used only on the Manchester and had the possibility of one further type - the Tornado. The Griffon was required by the FAA, and just so happened that they could fit it to the Spitfire, so it continued. Other projects were stopped (except the Crecy).

Given the resources, which RR didn't have to give, the Vulture could have been sorted and would have kept the Sabre honest.

#221 JAW

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Posted 14 January 2014 - 20:48

Wuzak, any conflict of interest to declare re R-R? Not on a P.R. retainer fee, pension or what-have-you?

 

Just asking, because the industrial/political chicanery of the company is on the record too, your 'doubts' notwithstanding..

& do you really think that R-R supported the Shackleton Griffons for all those decades - gratis?

 

Of ~8,000 Griffons built, apart from a thousand Spit/Seafires & a number of Firefles, most must have gone to Shacks,

surely..

 

& Bristol, in fact - had to be leaned on fairly heavily - to assist Napier with their sleeve valve issue - even in dire wartime..

 

Thanks for posting those links, on which page is the 2,500hp for take-off  Griffon info?

The BMEP is listed for the engines shown though.. & Sabre beats Griffon..

 

It is true that the Sabre was a fabulous -  if painful achievement, that a tiny impoverished mob like Napier & sons

actually eventually (with E.E. ) got the only 'hyper' mill into service - is creditable indeed.

 

Of course one ought to compare the best of breed, regardless of VE/VJ day dates - given the focus of the topic..



#222 Wuzak

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Posted 14 January 2014 - 23:21

Wuzak, any conflict of interest to declare re R-R? Not on a P.R. retainer fee, pension or what-have-you?


No.


Just asking, because the industrial/political chicanery of the company is on the record too, your 'doubts' notwithstanding..
& do you really think that R-R supported the Shackleton Griffons for all those decades - gratis?


That is not what I said. I said that I doubt that there was a huge profit in it.


& Bristol, in fact - had to be leaned on fairly heavily - to assist Napier with their sleeve valve issue - even in dire wartime..


Bristol were forced to give up trade secrets which cost them millions of pounds to develop. I can see the reluctance.


Thanks for posting those links, on which page is the 2,500hp for take-off  Griffon info?
The BMEP is listed for the engines shown though.. & Sabre beats Griffon..


The Griffon 57 could produce 2500hp on take-off with ADI. Per Alec Lumsden, British Piston Aero Engines and Their Aircraft. The 57 is not shown in that document.

Re those engine pamphlets and BMEP:

Sabre VA - BMEP = 239psi
Griffon 65 - BMEP = 256psi.

Note that the Sabre V was only just being fitted to Tempests in 1945 - the first Griffon 65s went into Spitfires in late 1943.

Sabre VII - BMEP = 321psi
Griffon 130 - BMEP = 311psi

So the Sabre has the advantage there, but not by a huge amount. Plus it is with ADI - the Griffon 130 was not fitted with ADI.


It is true that the Sabre was a fabulous -  if painful achievement, that a tiny impoverished mob like Napier & sons
actually eventually (with E.E. ) got the only 'hyper' mill into service - is creditable indeed.
 
Of course one ought to compare the best of breed, regardless of VE/VJ day dates - given the focus of the topic..


What do you call a "hyper mill"?

> 1 hp/ci & > 1 hp/lb as the Americans defined it in their Hyper program? Then the Merlin and Griffon both achieved that during the war.

#223 JAW

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Posted 15 January 2014 - 01:40

Yeah, 'hyper' may've been just another bit of American hype, really..

Since none of their ( or the Germans nor R-R, either) 24 cyl liquid cooled 2,000+hp engines achieved much.

 

However, that Sabre 7 did achieve a rated 1.56hp/ci.

 

& so, the Sabre must stand as the most likely benchmark power density-wise,

for any prospective answer to the topic question posed.



#224 Greg Locock

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Posted 15 January 2014 - 02:14

That's a rather silly performance indicator from any practical perspective. Power per installed cubic ft, or power per installed lb, would be a far better measure of the real usefulness of an engine in an aircraft.  



#225 JAW

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Posted 15 January 2014 - 02:27

Hardly 'silly', since it is a prime performance indicator of any I.C. engine..

 

However, for that Sabre rated @ 3,500hp for take-off,

- it was also good for..

 

0.73lb/hp, .....weight to power,

7.44hp/sq.in.. power/piston area,

3,048 ft/min...piston speed (max),

0.45 lb/hp/hr..S.F.C, (cruise)..

 

Frontal area 8.8 sq.ft

 

Some fairly good numbers, even today, let alone for a 5in x 4.75in ( 24cyl) mill.

 

~70 years ago..


Edited by JAW, 15 January 2014 - 02:32.


#226 Greg Locock

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Posted 15 January 2014 - 04:23

Oh, so you mean that an aircraft designer would rather have a larger or heavier engine with a smaller swept volume that produced the same power? What a strange world you live in.



#227 JAW

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Posted 15 January 2014 - 05:24

Ah, that'd be planet Earth, last time I looked..

 

& do you actually read/comprehend the posts?

 

Feel free to find & post an example of any 4-stroke general aviation,  rated mill that beats those Sabre numbers posted..



#228 Wuzak

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Posted 15 January 2014 - 05:36

Ah, that'd be planet Earth, last time I looked..
 
& do you actually read/comprehend the posts?
 
Feel free to find & post an example of any 4-stroke general aviation,  rated mill that beats those Sabre numbers posted..


Rolls-Royce Merlin RM.17SM.

Didn't go into production because the end of the war.

Rated power: 2200hp @ 3000rpm, ~1650lb. = ~0.75lb/hp.

(Incidentally the 130 series Merlins and the Packard V-1650-9 were rated at 2200hp, the latter with ADi, the former derated after the war).

Flight cleared power: 2380hp @ 3300rpm = ~0.69lb/hp.

Maximum tested power: 2620hp @ 3150rpm = ~0.63lb/hp.

You may well come back and say that the Sabre was tested at 5000hp. But that was very much later. The RM.17SM test powers were run in 1944.

Frontal area 6.1sq.ft. Not that the Griffon's was 6.6sq.ft, a small increase for a 30%+ increase in capacity.

Edited by Wuzak, 15 January 2014 - 05:38.


#229 Wuzak

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Posted 15 January 2014 - 05:47

Yeah, 'hyper' may've been just another bit of American hype, really..
Since none of their ( or the Germans nor R-R, either) 24 cyl liquid cooled 2,000+hp engines achieved much.


The Vulture was cancelled before the Sabre went into service, possibly before it was in production. Powered the Manchester (poorly), the Tornado (somewhat more reliably) and the Blackburn B.20. Cancelled to free up resources for more critical engines - ie the Merlin and Griffon. Tested at 2500hp before cancellation (early 1941).

The Vulture powered Tornado was still being used for testing in 1943/44 - it was a test bed for de Havilland contra-props.

Hawker-Tornado-R7936-contra-rotating.jpg

The Eagle 22 project only started in 1943/44. Only a handful of prototypes were built before project was cancelled in favour of gas turbine work. Staretd at 3200hp from 2800ci, though it was a sizeable and heavy lump.

The Pennine was an air-cooled X-24 of 2750ci. One built. ~2800lb. 2800hp in early testing. Cancelled in favour of jets.

There was the Exe, though it was not >2000hp, just over 1000hp in fact. Cancelled to concentrate on Merlin and Griffon.


Edited by Wuzak, 15 January 2014 - 05:47.


#230 JAW

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Posted 15 January 2014 - 05:49

Agreed, what was obtained from the Merlin was a splendid achievement,

& the performance of the 'little Limey' mill still really bugs certain US engine fans..

..but  being 'later' - somehow disqualifies the prodigious Sabre?

 

We are, surely, discussing the fanciful potential ( 'cepting SFC efficiency) of new built big recips challenging turbo-shafts, right?

 

Incidentally, I ran the question of a Sabre being overhauled to fly - past Reno race engine guru Mike Nixon,

& he reckons it'd be perfectly straightforward & feasible, so now - we just need to dredge one up & crowd fund it..


Edited by JAW, 15 January 2014 - 05:50.


#231 JAW

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Posted 15 January 2014 - 05:57

Wuzak, do you know why R-R was loath to add ADI to its British built birds?

 

The Sabre 7 figures were 'rated', I take it only the P/Merlin-9 could come near them, as an officially rated R-R mill? 



#232 JAW

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Posted 15 January 2014 - 07:22

Wuzak, looking at the obvious similarity of the Griffon off-centre annular radiator set-up for both the Shack' & the Fury..

 

I must ask..

 

With your store of R-R knowledge, do you know if that  design was an R-R item, - much like Napier did their annular type?



#233 Wuzak

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Posted 15 January 2014 - 07:48

Wuzak, looking at the obvious similarity of the Griffon off-centre annular radiator set-up for both the Shack' & the Fury..
 
I must ask..
 
With your store of R-R knowledge, do you know if that  design was an R-R item, - much like Napier did their annular type?


Probably.

Rolls-Royce definitely did the ones for the Shackleton.

They developed a similar installation for the Merlin for ailine applications.

#234 Wuzak

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Posted 15 January 2014 - 07:55

Agreed, what was obtained from the Merlin was a splendid achievement,
& the performance of the 'little Limey' mill still really bugs certain US engine fans..
..but  being 'later' - somehow disqualifies the prodigious Sabre?


3 or 4 years more development certainly helps.

After the war the Merlin was developed for civil aviation, and thus was not pushed anywhere near its war time limits. Instead they sought to extend the TBO and increase the maximum cruise (continuous) power.

The Sabre VII, which has the spectacular performance numbers, was still being developed for military customers, even though it didn't really have any.

By that stage Rolls-Royce had well and truly moved onto gas turbines. As had the Sabre's designe - Frank Halford, who had moved to de Havilland and developed the Halford H.1/de Havilland Goblin, which was running in 1943.

ADI. Don't think RR thought it necessary during the war. The Merlin and Griffon 2 stage engines had intercooling and aftercooling. The RM.17SM did, however, run in 1944 with ADI, allowing a maximum boost of +36psi. And, of course, the Shackleton's Griffon used ADI for take-off - same as for the Sabre VII.

#235 JAW

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Posted 15 January 2014 - 09:06

Yeah, ta, mate poor ol' Napier (& Bristol too, in turn) were eventually smothered by R-R  commercial/political nouse..

 

Even to the extent of Merlins being sold & fitted to new-build fascist 109 analogues in Spain..

 

I guess the several thousand excess Sabres built, but not utilized in WW2  - were fairly freely expended in colonial Tempest F6,

& TT5 usage extending into the mid `50s,-  then they were pretty well mostly just scrapped..

 

Unless someone has one or 3 , tucked under a tarp in a shed somewhere.. like Kermit Weeks..

 

Maybe when the situation in Sudan settles down ..

..Monster Energy & Nat Geo can sponsor a fishing trip to the Nile..

..at Khartoum - where a bunch of them were simply dumped off the jetty- still new/greased - in crates after the Tempest F6 tropical trials

finished..



#236 Greg Locock

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Posted 15 January 2014 - 20:02

Hardly 'silly', since it is a prime performance indicator of any I.C. engine..

 

 

Not from an aircraft designer's , or system engineering, perspective. It's a number for bragging rights, for engine designers and wannabes. and yes virginia, I have worked on crankshafts and related parts for production engines.



#237 JAW

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Posted 15 January 2014 - 21:16

Sorry to burst your bubble old boy,

but - regardless of how much swarf you've personally swept,

that figure really is - a meaningful, & standard - performance indicator.



#238 gruntguru

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Posted 16 January 2014 - 00:25

Sure it is a standard performance indicator - great for comparing engine designs. However it would be well down the list of criteria when choosing an engine for an aircraft, in fact it could be completely disregarded. Provided the chosen engine was superior in kW/kg, kW/m^2, kW/m^3 and g/kW.hr it wouldn't matter if the BMEP was half.


Edited by gruntguru, 16 January 2014 - 00:27.


#239 Greg Locock

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Posted 16 January 2014 - 00:35

Engineers and non engineers, two cultures separated by a common language!



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#240 JAW

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Posted 16 January 2014 - 01:07

Relevant to parameters, or simply an interesting maths ratio-marker of specific output,

it is, none-the-less,  one of the standard figures listed, & quite properly so..



#241 Wuzak

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Posted 16 January 2014 - 01:17

Even to the extent of Merlins being sold & fitted to new-build fascist 109 analogues in Spain..

 

And what, exactly, were the alternatives?

 

Daimler-Benz and Junkers were out of the aero engine building business. As was BMW, but their radial was too big for the airframe, at least without substantial redesign.

 

The Sabre was too big and far too powerful for the airframe. Especially for take-off, with that skinny undercarriage.

 

So, the best available alternatives were the Merlin, V-1710 and the Hispano-Suiza 12Z. The latter powered some of the post war 109 derivatives.



#242 JAW

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Posted 16 January 2014 - 01:23

Wuzak, Napier & sons certainly weren't shy about innovative designs,

( Cub, Lion, Deltic,  Nomad & etc, let alone Halfords work).

 

 What the Lion was persuaded to produce in race-tune was quite impressive as development,

 & in sheer power out-put terms/results too..

 

Frank Halford designed engines for De Havilland, both before,  & after the Sabre, too..



#243 JAW

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Posted 16 January 2014 - 01:28

Well, Wuzak, since the 109 had difficulty coping with the Jumo lumped on it by Avia,

it certainly would have found a Sabre too big & meaty for sure..

 

My point was not so much technical ( Allison as an alternative , as it is today, perhaps?)

but  rather, as another example of R-R business push being purlind to potential qualms

ethics-wise..


Edited by JAW, 16 January 2014 - 01:29.


#244 Wuzak

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Posted 16 January 2014 - 02:06

Wuzak, Napier & sons certainly weren't shy about innovative designs,

( Cub, Lion, Deltic,  Nomad & etc, let alone Halfords work).

 

 What the Lion was persuaded to produce in race-tune was quite impressive as development,

 & in sheer power out-put terms/results too..

 

Frank Halford designed engines for De Havilland, both before,  & after the Sabre, too..

 

Frank Halford was a contractor. Not a Napier employee.

 

The Napier Cub was the world's first 1000hp rated engine. They built 6 of them.

 

The Deltic was based on the Culverin, which was a licence built Junker Jumo 204.

 

In race tune the Lion was able to get maybe 800hp. That was by 1929, some 10 or 11 years after production first started. The Rolls-Royce Buzzard was bigger and heavier, but could produce that in production form. The racing Buzzard, the 'R' started at 1900hp and ended at 2900hp in 1931.

 

The Nomad was, perhaps, beyond Napier's technical abilities. And, perhaps, largely irrelevant, since at the time the move was to gas turbines - jet and turboprop.

 

Halford's Napier work was confined to the Rapier (twin crank air cooled H-16), which saw very little use as the engine was too small and not powerful enough, the Dagger (air cooled H-24), which was even less successful than the Rapier and was bugged by cooling issues, not to mention causing air crew to become sick because of the high pitched noise, and the Sabre.

 

The designer of the Lion, Arthur Rowledge, moved to Rolls-Royce a few years later.



#245 JAW

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Posted 16 January 2014 - 02:31

Yes, Frank Halford was busy as a designer, & as noted - did quite a few aero-engines, for D.H. as well as N.& S.s',

 

Might want to revise those Lion race-tune figures, though, W.,

..since J.C.'s Napier-Railton World Land-speed Record machine was

a fair bit more grunty than 800hp per mill,& had more than

enough power to spoil R-R's day, in fact,  type-R or no...

 

The Nomad is quite relevant to this thread topic too, I'd reckon..

..commercial/political out-comes ( Napier & Bristol squeezed out of aero-engines by R-R),

notwithstanding..

 

Like the Vulture, bomber drudge-duty was not the Dagger's forte`, true enough..



#246 bigleagueslider

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Posted 16 January 2014 - 02:56

B-L-S, you do realize that the German DFI used on their big aero-mills was directly injecting petrol/gasoline into each cylinder,

- to ensure even mixture, it was based on Diesel injection systems & typically Germanic in precision/complexity/cost..

 

That precision was what made it attractive to use in big radials where mixture distribution could be problematic & inefficient,

compared to the even firing multiples of 120` cylinders so logically laid out - typical of well designed inline mills.

JAW- Yes, I understand how the DFI systems used on WWII German recip aircraft engines functioned. But what I don't think you understand is that these crude mechanical GDI systems were not any better at accurately controlling fuel/air mixtures from cylinder to cylinder, or over the speed/load/altitude operating range of the engine, than were the carburetor designs used by the Allies.



#247 JAW

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Posted 16 January 2014 - 03:16

B-L-S, clearly the German DFI systems were neither as 'crude' as you think, or as inefficient,

other-wise they would not have been productionised, being comparatively complex & costly..

 

The mixture distribution issue in a common manifold is simplified by DFI,

since  there is air only, - up-stream of each cylinder..

 & not a hot, pressurised, combustible, flame/back-fire  prone fuel/air mix, - up-stream of numerous cylinders..

 

This fuel mixture distribution issue was more problematic at the higher boost levels employed

with Allied Hi-Test grade fuel too..( on some engines, whereas the Sabre was smoother at higher boost levels)..


Edited by JAW, 16 January 2014 - 03:19.


#248 JAW

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Posted 16 January 2014 - 05:09

Wuzak,

 

Yes, the Napier Cub  - was as you write - the 1st  thousand hp mill,

- too bad there weren't suitable air-frames for it..

 

& the Deltic, yes it was a development of esentially Jumo  design principles,

but a stupendous achievement, & one good enough for the U.S. Navy..

 

Nomad, again was ambitious, but sadly typical of many British innovations,

cut off dead - when almost there, ( R-R dirty work afoot there too..)

 

Both high efficiency 2T turbo-diesel units, that are still pretty wow-factor impressive.

 

& of course the Lion,

1st mill to  power the World Speed Record holders..

.. on land, sea & air..

..at the same time..



#249 Wuzak

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Posted 16 January 2014 - 05:58

Nomad, again was ambitious, but sadly typical of many British innovations,
cut off dead - when almost there, ( R-R dirty work afoot there too..)


No Rolls-Royce dirty tricks. Just had no market.

Before you say the Shackleton was the market:

  • There were 185 Shackletons built
  • Meaning a market for the Nomad, at best, for half of them (by the time the Nomad made it to production).
  • That means <400 required plus spares - call it 500. Not nearly enough economy of scale to build the complex Nomad at a competitive price.
  • The Griffon was already in production.
  • The counter rotating props had been developed.
  • It was a, relative to the Nomad, cheap engine.

Airline manufacturers weren't interested - they were going for jets.
The military had no use for a new piston aircraft engine

 

& of course the Lion,
1st mill to  power the World Speed Record holders..
.. on land, sea & air..
..at the same time..


A distinction the Rolls-Royce R also held. I was under the impression that the R was the only one to be able to claim that.

As far as I can tell, the water speed record held by the Lion was only for single engined boats - not the absolute record.

The Lion, btw, held the Air Speed Record for 2 days....before being beaten by the R powered Supermarine S6.


Edited by Wuzak, 16 January 2014 - 05:59.


#250 Catalina Park

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Posted 16 January 2014 - 06:24

Sorry to burst your bubble old boy,

but - regardless of how much swarf you've personally swept,

that figure really is - a meaningful, & standard - performance indicator.

:rotfl:   :rotfl:  :rotfl:    What a crack up. You really got him. You should do stand up.