"No sleeve-valve engines" scenarios

[Shortround6]

If the sleeve valves failed, would this engine have done better if it had the same resources thrown at it as the Vulture?

You can fix just about anything if you throw enough money and time at it. The question is should you?

When your research and development (resources) starts doing things like getting the intake manifolds/passages out of the crankcase, modifying the valves and cylinder heads, beefing up crankshafts and other parts you might wonder wither you should have started with something else to begin with.

Take another look at it, it is not a fighter engine, it is a bomber (big bomber) or perhaps maritime patrol plane engine, being able to shut 1/2 the engine and cruise on the other half? However this also means you need twice the instruments, twice the controls, separate oil and coolant systems and so on. Perhaps the engine could have been simplified but it was too dated.

Old Machine press has quite a write-up on it and a good look at some of the patent drawings will show some of the problems. If people think the Allison had poor intake manifolds this thing was a horror. At least you could replace the allison manifolds without replacing the crankcase.

 

[jetcal1]

You can fix just about anything if you throw enough money and time at it. The question is should you?

When your research and development (resources) starts doing things like getting the intake manifolds/passages out of the crankcase, modifying the valves and cylinder heads, beefing up crankshafts and other parts you might wonder wither you should have started with something else to begin with.

Take another look at it, it is not a fighter engine, it is a bomber (big bomber) or perhaps maritime patrol plane engine, being able to shut 1/2 the engine and cruise on the other half? However this also means you need twice the instruments, twice the controls, separate oil and coolant systems and so on. Perhaps the engine could have been simplified but it was too dated.

Old Machine press has quite a write-up on it and a good look at some of the patent drawings will show some of the problems. If people think the Allison had poor intake manifolds this thing was a horror. At least you could replace the allison manifolds without replacing the crankcase.

Given the scenario presented of "no-sleeve-valve-engines" does the Fairey product become worthy of further development? Does the ministry hand it off to Napier or Bristol in say 1938? (Or even earlier)

As far as the instrumentation? Dual pointer instruments were available at the time and do not pose a insurmountable issue. Weight wise, the engine appears to be about the same as a Sabre. Dimensionally, I'd bet they're close...(With the deck height advantage going to the Sabre.) As far as heat rejection? again, probably about the same as a Sabre or a Griffon. (How many radiators under the wing or in the root of a Spitfire or Tempest?)

In fact, I'll say for the fun of it that redundant systems if they could be packaged in an envelope similar to that of the Griffon or the Sabre would enhance combat survivabilty.

 

[wuzak]

Given the scenario presented of "no-sleeve-valve-engines" does the Fairey product become worthy of further development? Does the ministry hand it off to Napier or Bristol in say 1938? (Or even earlier)

It didn't run until 1939, and then only half of it. So the handover would not occur before then.

Doubtful that Bristol would be considered - they were the air-cooled engine supplier (Armstrong-Siddeley was supposed to be as well, which is why the Deerhound was air-cooled rather than liquid-cooled as first proposed).

And Napier would be well into their Poppet-Sabre, I would imagine.

As far as the instrumentation? Dual pointer instruments were available at the time and do not pose a insurmountable issue. Weight wise, the engine appears to be about the same as a Sabre. Dimensionally, I'd bet they're close...(With the deck height advantage going to the Sabre.) As far as heat rejection? again, probably about the same as a Sabre or a Griffon. (How many radiators under the wing or in the root of a Spitfire or Tempest?)

I'd have to check reports I have, but 2,180lb seems light.

Dimensions:
Engine................Height....Width.....Length.....Weight
P.24 Monarch...52.500in...43.0in...86.250in...2,180lb
Sabre...............46.000in...40.0in...82.250in...2,360lb
Vulture..............42.175in...35.8in...87.625in...2,450lb
Griffon..............46.000in...30.3in...81.000in...1,980lb

All from Wiki, except Vulture, which was from RRHT.

The Griffon's length may not be measuring the same dimension as the others, since it is shorter than the 2 stage Merlin. Note also that the Griffon is the 2 stage 65, which adds weight and length.

In fact, I'll say for the fun of it that redundant systems if they could be packaged in an envelope similar to that of the Griffon or the Sabre would enhance combat survivabilty.

The fact that both halves of the engine share the same crankshaft (and maybe cooling system too) means that the redundancy doesn't necessarily enhance surviveability.

Plus they are close together, so a shell damaging one half may well damage the other half.

 

[wuzak]

Also, there have been a few threads about the Fairey P.24 over the years.
Fairey aero engines - any good info?

If I may quote myself:

The Fairey P.24 Civil Type Test [50h] was undertaken between 13 May 1939 and 14 June 1939.

The rated output was 1205hp @ 10,500ft at 2400rpm.
The maximum output was 1450hp @ 10,500ft, maximum speed 2750rpm.

Bore: 5.254" (133.5mm)
Stroke: 6.00" (152.3mm) [from the report, should be 152.4mm if it is 6"]
Capacity 3124.3ci (51.2l)

BMEP at rated hp at "International RPM" was 127psi.

The carburetors were fitted with automatic boost controls.

Nett dry weight was 2202lb, gross dry weight (not including propeller hubs or engine mounting) was 2329lbs.

 

[wuzak]

I wonder if Rolls-Royce and Napier could have been made to work together on the Vulture if the Sabre turned out to be a dead end.

Or Napier would tell them to go away and build a Poppet-Sabre.

 

[jetcal1]

Also, there have been a few threads about the Fairey P.24 over the years.
Fairey aero engines - any good info?

If I may quote myself:

May I have some fun?
Double Wasp S1A4-G
The rated output was 1850hp @ 2700ft 2600 RPM versus Fairey 1205hp @ 10,500ft at 2400rpm.
The maximum output was 1500hp @ 13,000ft, maximum speed 2600 RPM. Versus Fairey 1450HP at 10,500 Ft 2750 RPM
(100 Octane for the R2800)

R2800 Dry Weight 2300 lbs
Fairey Dry Weight 2202
I wonder what the numbers would look like if the R2800 was run on the same fuel as the Fairey engine? And if the Fairey engine had 50% of the resources thrown at the Sabre or the Vulture. (Remember, we're what if here.)

My whole point has been is the engine may have had more potential than it has been given credit for. And, given the no sleeve valve scenario, we've just made a whole lot of engineering and manufacturing capacity available in an industry that was literally starved for it between 1936 and 1945.

 

[davparlr]

Designers were a lot more obsessed with hp per sq/ft of frontal area at the time which influenced cylinder arrangements.

Speaking of hp per sq/ft, this is a bit off subject, but I saw at the National Air Force Museum a strange engine but I could never find much about it. It primarily operated off a slanted plate on the drive shaft, I'm sure there is a name for it, which operated on pistons operating parallel to and around the drive shaft ala 1960s GM air conditioner compressor. It certainly operated on a reduce frontal area. It must have had serious problems as I never read anything about it. Let me know if you are anyone else has any information on this particular engine implementation.

 

[fastmongrel]

Sounds like a Swash plate engine.

 

[wuzak]

That would be the Almen A-4 "barrel" engine.

Almen A-4 Barrel Engine by mark6mauno, on Flickr

And it is an axial piston engine.

 

[swampyankee]

Swashplate engines were one of the more-or-less dead ends of combustion engine technology. Interestingly, they are used for some very successful hydraulic pumps and motors.

 

[Shortround6]

I wonder what the numbers would look like if the R2800 was run on the same fuel as the Fairey engine? And if the Fairey engine had 50% of the resources thrown at the Sabre or the Vulture. (Remember, we're what if here.)

I wonder what the numbers would have looked like if the Fairey engine tried to pass an American type test?

and P & W worked up some figures for the R-2800 running on 90 octane fuel even if they didn't actually build such engines (maybe to find out what the engine could do if they couldn't get 100 octane?) in any case 1625hp/2600rpm at sea level for take-off. 1625hp/2600rpm at 6500ft and 1250hp/2600rpm at 16,800ft in low and high gear military power and 1450hp/2400rpm at 8500ft and 1200hp/2400rpm at 16,000ft max continuous.

Something wrong with the Fairey's superchargers?

Resources can help but they can't change the laws of physics. You design a convoluted intake duct with lots of sharp turns and no amount of resources is going to be able "fix" it.
You need to throw it out and start over. The siamesed intake ports and two of the four exhaust ports are siamesed, Ok on low powered engines, not so good on high powered ones,
Development and resources often meant an increase in weight. Three countries tried to "improve" the Hispano V-12. ALL three succeeded by around 1947-48. All three got 30-40% more power than the pre war engines got. ALL three gained several hundred pounds, including much heavier crankshafts. All three resorted to new cylinder heads. At least two used fuel injection. All used new or different superchargers. All three failed to catch the Merlin.

 

[Timppa]

How much this change the 'scene', predominatly at Bristol and Napier? Gains vs. losses? Possible effects on ww2 design and production of both engines and related aircraft?

Start making Merlins and Griffons under license.
Halifax, Beaufighter, Wellington with Merlins, up to its 2,000 hp versions.
Typhoon/Tempest with Griffon (the latter with a 2 -stage version).

 

[swampyankee]

Start making Merlins and Griffons under license.
Halifax, Beaufighter, Wellington with Merlins, up to its 2,000 hp versions.
Typhoon/Tempest with Griffon (the latter with a 2 -stage version).

Note that there were some quite high performance radials with poppet valves, so it's probable that Bristol would be making equally high performance radials with poppet valves. I would find it quite hard to accept an argument that the Centaurus was hugely better than the R-3350 or R-2800. The sleeve valve brought an entirely new set of challenges, a set most manufacturers (and all outside of the Commonwealth) thought could be overcome, but just not worth the bother for the limited benefits.

Bristol would just make poppet valve radials. Napier is a different case. Their production engines, just before the Sabre, were overly complex, not terribly reliable, quite expensive (more cylinders will do that), and with little or no performance advantage over competitors, and the company was just hanging on. Were I the Technical Lord of the Air Ministry, I'd be torn between telling them to start making Merlins and Griffins under license and telling them to build a poppet valve engine with to the same spec as that which led to the Sabre. Since they had diesel experience, my twin brother, over at the Admiralty, would tell them we need high-power density, light weight diesels for the MGB and MTB right now. They could start with the Culverin or Cutlass. Opposed-piston "V" engines had been built (by Fairbanks Morse, among others), so they could produce V-12 or H-12 derivatives of either (pick one)

 

[fastmongrel]

Bristol would just make poppet valve radials

I agree. Bristol with very little effort and a small engineering team turned out the Mercury which in 1941 with 100 octane was knocking on the door of 1,000 hp at about 1,000 lbs. Not bad for a 1500"/25 litre engine.

The Swedes were claiming 980 hp for the license built Svenska Flygmotor Mercury in the B17 dive bomber.

That might have been on the verge of going bang for a a fairly old design but it shows Bristol could build a decent poppet valve engine.

A poppet valve engine with 14 Mercury sized cylinders with the unnecessary 4 valves flapping in the breeze cylinder head made into a neater 2 valve enclosed version could have been a very useful engine in 1939.

A 51 inch diameter, 14 cylinders, 1500 lb and 1350 hp engine, aircraft designers would have bitten Bristol's hand off.

 

[jetcal1]

I wonder what the numbers would have looked like if the Fairey engine tried to pass an American type test?

and P & W worked up some figures for the R-2800 running on 90 octane fuel even if they didn't actually build such engines (maybe to find out what the engine could do if they couldn't get 100 octane?) in any case 1625hp/2600rpm at sea level for take-off. 1625hp/2600rpm at 6500ft and 1250hp/2600rpm at 16,800ft in low and high gear military power and 1450hp/2400rpm at 8500ft and 1200hp/2400rpm at 16,000ft max continuous.

Something wrong with the Fairey's superchargers?

Resources can help but they can't change the laws of physics. You design a convoluted intake duct with lots of sharp turns and no amount of resources is going to be able "fix" it.
You need to throw it out and start over. The siamesed intake ports and two of the four exhaust ports are siamesed, Ok on low powered engines, not so good on high powered ones,
Development and resources often meant an increase in weight. Three countries tried to "improve" the Hispano V-12. ALL three succeeded by around 1947-48. All three got 30-40% more power than the pre war engines got. ALL three gained several hundred pounds, including much heavier crankshafts. All three resorted to new cylinder heads. At least two used fuel injection. All used new or different superchargers. All three failed to catch the Merlin.

I'm not arguing with your points, an earlier post in this thread stated the Vulture was redesigned.

In real life? I agree this engine is not worth pursuing.

For the purposes of this thread, unlike the "Dog" engines which appear to all have been highly stressed air-cooled high RPM engines I'm suggesting that since there is now a shortage of Napier and Bristol engines with a butt-load of bare firewalls, this engine might have been worth resuscitating. (Because the sleeve-valve has now become as rare as a Bigfoot or a Chupacabra.)

 

[davparlr]

Swashplate engines were one of the more-or-less dead ends of combustion engine technology. Interestingly, they are used for some very successful hydraulic pumps and motors.

There must be something inherently flawed about the design to just disappear. It seems to offer significant benefits to aircraft designers such as burying the engine in the wings of bombers significantly reducing not only area drag but also interference. And, How much more space would be available in a P-39 for a turbo-supercharger, and so on. Tis a puzzlement.

 

[Shortround6]

Not really.
The main problem is the limited number of cylinders. If you can only get 80-100hp per cylinder on a given type of fuel and you are happy with a 300-600 hp engine (4 to 6 cylinders) then they may provide an alternative form of engine. If you are looking for a 1200hp engine and you arrange 12 cylinders in a circle like a big revolver cylinder then the bulk and weight may or may not be competitive with either a V-12 or a two row 14 cylinder radial. Want more than 1200hp? P&W R-2800 was making 111hp per cylinder at 2000hp. 18 cylinder swashplate engine

 

[swampyankee]

Not really.
The main problem is the limited number of cylinders. If you can only get 80-100hp per cylinder on a given type of fuel and you are happy with a 300-600 hp engine (4 to 6 cylinders) then they may provide an alternative form of engine. If you are looking for a 1200hp engine and you arrange 12 cylinders in a circle like a big revolver cylinder then the bulk and weight may or may not be competitive with either a V-12 or a two row 14 cylinder radial. Want more than 1200hp? P&W R-2800 was making 111hp per cylinder at 2000hp. 18 cylinder swashplate engine

That may be one issue, but another may be that the swashplate or wobble plate (they're different) may get very heavy at high powers.

 

[davparlr]

Not really.
The main problem is the limited number of cylinders. If you can only get 80-100hp per cylinder on a given type of fuel and you are happy with a 300-600 hp engine (4 to 6 cylinders) then they may provide an alternative form of engine. If you are looking for a 1200hp engine and you arrange 12 cylinders in a circle like a big revolver cylinder then the bulk and weight may or may not be competitive with either a V-12 or a two row 14 cylinder radial. Want more than 1200hp? P&W R-2800 was making 111hp per cylinder at 2000hp. 18 cylinder swashplate engine

According to several sources, John O. Almen engine was a 9 shaft engine with 18 opposing cylinders. His patent show 11 shaft driving 22 opposing cylinders. Valve action and flow reflect 1920 crudeness. So if he only could get 100 hp per cylinder, the engine would generate 1800 hp, an impressive engine. Of course that is simplistic, but still seems worth developing.

https://patentimages.storage.googleapis.com/fc/ab/a6/9c7464ff531cb1/US1233635.pdf

 

[wuzak]

Not really.
The main problem is the limited number of cylinders. If you can only get 80-100hp per cylinder on a given type of fuel and you are happy with a 300-600 hp engine (4 to 6 cylinders) then they may provide an alternative form of engine. If you are looking for a 1200hp engine and you arrange 12 cylinders in a circle like a big revolver cylinder then the bulk and weight may or may not be competitive with either a V-12 or a two row 14 cylinder radial. Want more than 1200hp? P&W R-2800 was making 111hp per cylinder at 2000hp. 18 cylinder swashplate engine

As pointed out by davparlr, an axial engine can have 2 cylinders opposed in each position.

Axial Internal-Combustion Engines. Aluminium Materials by Braidy Industries.