Explore US alternatives to British sleeve valve engines (and the ramifications)

[gjs238]

I understand that the reason Roy Fedden persisted with sleeve valves was that he couldn't find a way to make a two-row radial with four valves. I can't remember the source for this, but I would note that all the poppet-valve two-row radials had only two valves.

With sleeve valve designs taking so long to develop (Bristol Hercules, Napier Sabre), it would be interesting to explore what if US designs were license built by Bristol, Napier and others.

With the necessary horsepower available, what British aircraft could have been developed and entered service sooner?

PS: Or perhaps it would be easier to have Bristol, Napier and others license build RR products.

 

[Shortround6]

For Bristol the only real alternative is the Wright R-2600. It fits both dimension and weight wise. It also fits time wise. The R-2800 is too late.

The question becomes can Bristol actually build it and which version. British casting wasn't up to US standards in the early 30s which is why they went to forged cylinder heads and US companies stayed with castings for a number of years more.

 

[tomo pauk]

With hindsight, the most important UK-built machines relied on RR Merlin. Non-existence of the Sabre would not harm the Allied war effort much. However, having more companies in the race means that all of them are competitive, rather than to sleep on the laurels.
With RR having less pressure for Merlin program (with either Napier, or Bristo,l or both included in production), maybe the Griffon can be developed earlier? But even so, until it is in two-stage variant, it won't cut it for the Typhoon.
Following that: Armstrong-Siddeley or/and Alvis, with blessing on UK government, produce either R-2600 or R-2800, with Bristol/Napier producing RR products. Of US engines, only the R-2800 makes sense for the Typhoon; the R-2600 was tested on Australian Beaufighter. Historically, Alvis licensed G R radial (14N?). The R-2600 was wider than Hercules, 55 in vs. 52 in diameter, and not that good at higher altitudes.
Another path might be that Griffon is postponed, and Vulture gets more attention.

 

[wuzak]

What about an up-sized, liquid-cooled version of the Dagger?

ie H-24, ~2,200-2,250 cid (Griffon and Sabre ~2,240cid).

In fact, it could be the Sabre, except with poppet valves instead of sleeve valves.

Or perhaps Napiers would opt for a Merlin sized engine using the layout of the Lion.

 

[gjs238]

For Bristol the only real alternative is the Wright R-2600. It fits both dimension and weight wise. It also fits time wise. The R-2800 is too late.

The question becomes can Bristol actually build it and which version. British casting wasn't up to US standards in the early 30s which is why they went to forged cylinder heads and US companies stayed with castings for a number of years more.

The nice thing about the R-2600 is that it was a developed design - R-2600 powered Boeing 314 Clipper's were flying around the globe, entering regular service in January 1939

From Wikipedia:
The first 314, Honolulu Clipper, entered regular service on the San Francisco-Hong Kong route in January 1939. A one-way trip on this route took over six days to complete. Commercial passenger service lasted less than three years, ending when the United States entered World War II in December 1941.
At the outbreak of the war in the Pacific, the Pacific Clipper was en route to New Zealand. Rather than risk flying back to Honolulu and being shot down by Japanese fighters, it was decided to fly west to New York. Starting on December 8, 1941 at Auckland, New Zealand, the Pacific Clipper covered over 31,500 miles (50,694 km) via such exotic locales as Surabaya, Karachi, Bahrain, Khartoum and Leopoldville. The Pacific Clipper landed at Pan American's LaGuardia Field seaplane base at 7:12 on the morning of January 6, 1942.

 

[bobbysocks]

this is the first i have seen this set up. what were the virtues of the sleeve valve? seems like a very cumbersome system of heavy parts that had to overcome a lot of friction.

 

[wuzak]

this is the first i have seen this set up. what were the virtues of the sleeve valve? seems like a very cumbersome system of heavy parts that had to overcome a lot of friction.

The sleeve valve was promoted by Harry Ricardo in the 1920s as a solution to detonation problems with spark ignition engines running the poor fuels of the time.

It eliminated one point of the pre-ignition - the hot exhaust valve - and allowed higher compression than poppet valve engines.

The three major aero engine builders in the UK had some involvement with sleeve valves. Bristol, of course, had a range of sleeve valve engines - the Perseus, Taurus, Hercules and Centaurus. Napier had the Sabre.

Rolls-Royce's experience started with them assisting Ricardo in converting a Kestrel to a sleeve-valve Diesel (Diesel was another are being pushed as they don't have the issue of pre-ignition) known as RR/D. This was later converted to a spark ignition petrol engine (the RR/P) by Rolls-Royce. In the mid 1930s the Exe was designed and one built for testing. The program was cancelled in 1941. In 1943/44 Rolls-Royce designed the Eagle 22 (similar to the Sabre but bigger and heavier) and the Pennine (larger version of Exe).

What curtailed the uptake of sleeve valves was the invention of the internally sodium cooled exhaust valve and the development of higher octane, more detonation resistant, fuels with Tetra-Ethyl Lead (TEL).

 

[rinkol]

The nice thing about the R-2600 is that it was a developed design - R-2600 powered Boeing 314 Clipper's were flying around the globe, entering regular service in January 1939

From Wikipedia:
The first 314, Honolulu Clipper, entered regular service on the San Francisco-Hong Kong route in January 1939. A one-way trip on this route took over six days to complete. Commercial passenger service lasted less than three years, ending when the United States entered World War II in December 1941.
At the outbreak of the war in the Pacific, the Pacific Clipper was en route to New Zealand. Rather than risk flying back to Honolulu and being shot down by Japanese fighters, it was decided to fly west to New York. Starting on December 8, 1941 at Auckland, New Zealand, the Pacific Clipper covered over 31,500 miles (50,694 km) via such exotic locales as Surabaya, Karachi, Bahrain, Khartoum and Leopoldville. The Pacific Clipper landed at Pan American's LaGuardia Field seaplane base at 7:12 on the morning of January 6, 1942.

There are differing views on the R-2600, for example R-2600 Case History. It seems that Wright's performance on other engines also left something to be desired - the R-3350 exhibited terrible reliability for a considerable time. In contrast, the Hercules reached service in a reasonable time frame and seemed to be fairly reliable. I don't think there were many aircraft developments that would have taken place significantly faster with the R-2600 or any other alternative. In any case, it isn't a trivial job building a foreign engine design, particularly when many of the standards are different. One place the British did go wrong on was to maintain obsolescent types such as the Blenheim and Beaufort (and their engines) in production as long as they did.

 

[pbehn]

The sleeve valve was promoted by Harry Ricardo in the 1920s as a solution to detonation problems with spark ignition engines running the poor fuels of the time.

It eliminated one point of the pre-ignition - the hot exhaust valve - and allowed higher compression than poppet valve engines.

The three major aero engine builders in the UK had some involvement with sleeve valves. Bristol, of course, had a range of sleeve valve engines - the Perseus, Taurus, Hercules and Centaurus. Napier had the Sabre.

Rolls-Royce's experience started with them assisting Ricardo in converting a Kestrel to a sleeve-valve Diesel (Diesel was another are being pushed as they don't have the issue of pre-ignition) known as RR/D. This was later converted to a spark ignition petrol engine (the RR/P) by Rolls-Royce. In the mid 1930s the Exe was designed and one built for testing. The program was cancelled in 1941. In 1943/44 Rolls-Royce designed the Eagle 22 (similar to the Sabre but bigger and heavier) and the Pennine (larger version of Exe).

What curtailed the uptake of sleeve valves was the invention of the internally sodium cooled exhaust valve and the development of higher octane, more detonation resistant, fuels with Tetra-Ethyl Lead (TEL).

There were many theoretical advantages to sleeve valves, I don't know if they were ever fully explored because the companies concerned made such a dogs breakfast of it. There was a lot of infighting between companies not wishing to share expertise and Napier especially seemed to treat the whole thing as hobby at the start. In hindsight they should have given Napier the Griffon to make under Rolls supervision or used the R-2600. Having seen a cut away centaurus turning over it is a great piece of design, like an optical illusion.

 

[tomo pauk]

What about an up-sized, liquid-cooled version of the Dagger?

ie H-24, ~2,200-2,250 cid (Griffon and Sabre ~2,240cid).

In fact, it could be the Sabre, except with poppet valves instead of sleeve valves.

Or perhaps Napiers would opt for a Merlin sized engine using the layout of the Lion.

Fairey gets resources for H-16 or/and H-24 engines?
Maybe Napier should be better off with a 40 liter H-16 engine, with poppet valves - should give 2000 HP on 100 oct fuel?

For Bristol - the 'twin Mercury' seem to be a recurring idea. Though, it would take a lot of money to go both with sleeve-valve designs and a twin 'classic' engine in the same time.

 

[merlin]

There's not just US - in 1937 Alvis Pelides engine - it's UK version of the GR-14k a 14 cyl radial 2 row - was AM certified at 1.065 hp - 52" Dia engine weighing at 1190 lb. From Wiki: -

The Alcides of 1937 was another projected medium supercharged two row radial engine but was planned to have 18 cylinders with a displacement of 3,314 cu in (54.24 L) and a power output of 1,300 hp (969 kW). Again the Alcides Major was an improved fully supercharged version.

Seems an opportunity missed.

 

[tomo pauk]

The G&R 14N, let alone 14K would have nothing to offer vs. Merlin III, especially when it comes down to the power at altitude, usability of exhaust thrust and taking a full advantage of hi-octane fuels. Those engines lacked the central bearing, meaning that any sensible increase in power is out of the question.
Soviets pushed the M-88 as far as it went, 1100 HP seem to be the maximum, the genes came from the G&R 14K/N.

The 54L engine that gives 1300 HP, while only a paper project, is a non-starter The A-S Deerhound at least flew? Seems it managed 1500 HP on 87 oct.

 

[Shortround6]

Not really, the French licensed engines had a major flaw. NO center bearing on a two throw crankshaft. This severely limited the potential power of the engines. Please note that the Gnome-Rhone company addressed this issue with the 14R engine. Engine picked up about 400lbs with the new crankshaft and crankcase and better finning over the 14N and that engine was heavier than a 14K.

 

[merlin]

How would it compare to the Mercury, the diameter is only half-an inch more?

 

[tomo pauk]

More power than Mercury. However, Mercury was old news in late 1930s, both Bristol and Napier were trying to come out with a 2000 HP engines, Bristol also with a 1500 HP one.

 

[Shortround6]

How would it compare to the Mercury, the diameter is only half-an inch more?

14 cylinders compared to 9. Fewer valves more spark plugs for maintenance.

Mercury was around 200lbs lighter.

 

[gjs238]

A R-2800 powered Hawker Typhoon (in lieu of the Napier Sabre) might be interesting.

 

[tomo pauk]

It would've looked much like the Hawker Tornado that got the Centaurus installed in lieu of the Vulture ( picture). It will need the 2-stage variant to compete vs. Fw-190 at medium and high altitudes, though.

Here is the picture of the Australian modified Beufighter, with R-2600; the standard Beau is in the pic, so we can compare a bit. Please note the change in the layout of the nacelle, elongated probably to cater for the R-2600 bigger dimensions.

 

[Shortround6]

A R-2800 powered Hawker Typhoon (in lieu of the Napier Sabre) might be interesting.

It would be interesting but it would be too late.

In 1940 P W had built 17 R-2800s, 8 of those in Dec. and these are the 1850hp for take-off models. 1500hp at 14,000ft military power.
The 2000hp R-2800 single stage supercharger engine doesn't show up until Dec of 1941 with 4 built in that month (2 by P&W and 2 by Ford).

There are already several squadrons of Typhoons in service at that point (although plagued with troubles.)

Wright had completed 39 R-2600 engines in 1938, 163 in 1939.

It is about the only engine in service/production that could be adopted in time to do anything.

 

[merlin]

14 cylinders compared to 9. Fewer valves more spark plugs for maintenance.

Mercury was around 200lbs lighter.

So, how much faster could the Gloster f.5/34 go with another 220 hp i.e. 26% increase.

Alternative engines have been suggested in the past which include the P W R1830 weighing in at 1,250 lbs.