Advantages of sleeve valves for H-24 engines?

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Napier Power Heritage has this to say, which is I think given the complete void in the engineering files about this power rating the most likely explanation:

They say the E.122 (which is marked on a projected power curve elsewhere on this thread at 3500ho) was the Sabre Mk8 - which never existed and as you can see below is a very different engine. It needed in principle +25lbs boost to get that figure it appears, I have never found a figure above +17.5lbs for any Sabre that ever existed under any conditions
with any form of water injection or anything else.

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From Napier Power Heritage Trust website itself:

"The Sabre VIII (E122) Series engine of higher boost with 2 stage 3 speed Supercharger, contra rotating propellers and fan drive engine capable of 3,350 BHP was proposed but never built."

"The latest developments which include water / methanol injection have brought the maximum power output of the Series VII up to 3,055 BHP."

Link >

Sabre Engines with Bulk Injection carburettors

Sabre Engines with Bulk Injection carburettors The later Series IV Sabre engine was fitted with bulk injection carburettors. It had a single entry supercharger with strengthened supercharger and reduction gear drives to withstand the higher gross powers which result from the use of higher boost...
npht.org

Happy now ? or are Napier Power Heritage Trust full of anti sleeve conspiracy theorists too ?

 
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The contribution of the Meteor needs to be put in context. The V1s started flying on the night of 12/13 June 1944.

The first of only 20 production Meteor Mk.I (W,2B/23C Welland I engines) flew on 12 Jan 1944. One of these went to the USA as a quid pro quo for the P-59 delivered to Britain in 1943. The first delivery of these to 616 squadron was on 12 July 1944 while it was based in Somerset in the SW of England well away from any V1 activity. On 21 July 1944 it moved to Manston in Kent, one of the closest bases to V1 activity. It didn't fly its first Meteor sortie until 27 July 1944. And it was 4 Aug before it downed its first V1. It was however nearer the end of Aug before it became fully Meteor equipped. By late Sept 1944 the V1 sites had been overrun by 21st Army Group.

So compare the numbers of Meteors flying per day with that single squadron for only half the campaign, and only at full strength for about 25% of it, with the muliple squadrons equipped with Tempests, Mustangs and Spitfire XIV that flew throughout the V1 campaign.

The first production Meteor III didn't fly until 11 Sept 1944. And the first 15 had the same Welland I engines as the Mk.I. These aircraft were issued to 616 in Dec 1944 / Jan 1945 which used them until early April (including the detachment sent to the continent Feb/Mar 1945 - the last of these returned to Britain on 9 April 1945). The squadron began receiving Mk.III with W.2B/37 Derwent I engines from Feb 1945 which it seems fully replaced the earlier aircraft in April. Reportedly it had 17 Derwent engined Mk.III by 1 April 1945 when the whole squadron moved to the continent.

The wartime Meteor was only ever a low level production machine. The last of the 180 Mk.III were not delivered until the end of 1946. The second squadron (504 sqn) did not begin to re-equip until April 1945 with the next following in June (74 sqn), July (124 sqn) and Oct (222 sqn) 1945.

As for the engine nacelle / jet pipe shape of the Meteor Mk.III that someone mentioned, ISTR that there were 3 or 4 variations during the production run.


J.A.W. said:
Incorrect assumption, ADGB were surprised that the massive attack on the 'Diver' infrastructure in France had not been more effective,
& there was a scramble to reorganise the defence, by all means at hand, from balloons through flak to fighters.
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As for the efficacy of Operation Crossbow in destroying the V1 sites, the problem was that the design of the sites was changed by the Germans.

The early V1 sites, the so called "ski" sites were relatively easy to spot in aerial recce photos with their numerous distinctive concrete buildings and associated facilities that were not that easy to hide. They were however quite hard to destroy. The initial bombing campaign caused the Germans to abandon most of these (around 20-30 were sufficiently undamaged to be put into use later). By the end of May some 23,000 tons of bombs had been expended on them. So the bombing campaign was effective against those sites.

The Germans recognised the danger very early in the bombing campaign and produced a new design for the sites which they then placed in new locations. The so called "modified" sites were not easy to spot. Only one concrete building was erected and various concrete access roads laid. The previously easily identifiable feature, the launch rail was designed to be portable and easily assembled / dissassembled within hours as required when the site was required. When erected it simply sat on a number of small concrete pads. What did exist was then expertly camouflaged. And with so much allied air activity the Germans began moving by night and hiding during the day so covering any activity around the new sites. It was the 25th April 1944 before the first of these new sites was identified at Bel Hamelin near Cherbourg.

That sparked a whole new recce campaign to identify these "modified" sites, with 68 identified between Cherbourg & Calais by May. Due to a lack of aiming points (no ski buildings, no ramp etc) the "modified" sites had to be attacked at low level and that proved hard to do, particularly as the Germans sought to defend them.
 
Snowygrouch said:
Another person who cant read ?
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Ignored

Snowygrouch said:
Its entirely possible that a brief sprint test was made where once, for a few minuites "a" sabre of some description achieved a high power level.
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In normal usage, "sustained" is obviously incompatible with a "few minuites" [sic]. The rest of your statement is plausable.

Snowygrouch said:
This is literally nothing to do with the wartime usage of it, or what was type tested, and among all engines one can find high power tests
which are of no relevance to the real use of the engine.
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Agreed, however this is about your claim that it never ran at that power.

You have previously stated "The Hercules was a very very good engine indeed" and in this post you state "what a catastrophe there were". I find these two statements to be diametrically opposed.

Did Sleeve Valves Have an Advantage at Very High RPM?

I did not mean to insult your book. I do apologise, for I found your book to be a brilliant piece of research. What I was trying to say was that you have made your position clear that you believe, based on the documentation you have sourced, that the sleeve valve was a huge waste of time and money for a valve system that had no benefit over the poppet.

Snowygrouch said:
It is most amusing that you rate a book written from memory, many years after the facts, by someone who inspired people to use sleeve valves in the first
place is an un-biased source.
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Ricardo's book has had 5 editions, ranging from 1921 to 1969. He was writing as it happened.

Snowygrouch said:
There is no evidence in the napier archive that such an engine was ever built or ever actually ran. Their review documents wax lyrical about the high power achieved in the VII of 3050hp, why do none of them mention this magical 3500hp figure ?
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You have inadvertently misread the number. The power figure in Ricardo's book was 3600 hp, as I posted above. I consider a published works of a highly regarded engineer to be adequate evidence. You have made your position abundantly clear that you do not agree. I accept that. I find disagreements, preferably handled respectfully, to be a learning opportunities.
 
Simon Thomas said:
You have previously stated "The Hercules was a very very good engine indeed" and in this post you state "what a catastrophe there were". I find these two statements to be diametrically opposed.
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It may depend on which times (1940 or 1943 or post war) are being commented on.
From what I have read (not real extensive) the Hercules was turned into a very very good engines.
However this statement does not include a date or mark number.

Likewise the catastrophe statement. No date or mark number.
Early Hercules engines were something of a catastrophe. Short overhaul life, excessive oil consumption which lead to spark plug fouling which lead to engine/s stopping running in flight. (or not putting out enough power and vibrating badly) Getting this sorted out took a while. The accounts/stories often don't say when.
Late WW II engines used different size bearings and crankshafts to handle the higher powers. No shame their, many other engines went through several extensive revisions.
Post War Hercules engines had very long life, high power, very good reliability. Very good engines indeed.

Problem is that as a program wither they were worth it or not. The sleeve valve adventure was very, very expensive. It rarely could produce engines that were more effective than poppet valve engine of the same period in time, until after the war. And the post war engines for reasons that are not well documented did not find very much success in the world market.
Could be price, could be NIH in the North American market or that the North American air frame builders didn't want to use "furrin" engines.

Maybe the post war engines were as good as the R-2800s, trouble is few people wanted them. There were also financial considerations for many years. The British (and French?) trade balances were so out of whack that expensive domestic engines were preferable to cheap foreign (American) engines.

Both statements can be true, but not applied to the same point in time.

and the cost of the sleeve valve adventure is very hard to judge.
 
The fact that Ricardo makes an even higher claim, even further from any evidence of reality is hardly an increase in the strength your position.

Those are the editions, pray tell which one was written JUST as the Sabre VIII (which doesnt exist) was being tested ?



See the post from Napier Power Heritage Trust themselves the Sabre VIII / E.122 was never built, and the highest recorded rating for the VII was 3050hp with water injection. Which (unsurprisingly) supports everything I`ve said here - and I see you`ve nearly avoided mentioning (Post 161)

I see now you`ve decided that arguing is in the pursuit of sincere academic interest only, after having enjoyed trashing my book. Wonderful.
 
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Snowygrouch said:
I see now you`ve decided that arguing is in the pursuit of sincere academic interest only, after having enjoyed trashing my book. Wonderful.
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Please show me where I trashed your book.
 
Re-reading Ricardo's writings, we realize that he had built his first sleeve engine for testing in 1922, which allowed him to highlight the well-known "superiorities" of the system over poppet valves (see his text below , op.cit. p.321).

But at that time, what were the valves of high-power engines? Sam Heron's work had not yet been completed, neither about finning of air-cooled cylinder heads, nor on sodium valves, and the engine most representative of the traditional system was the Jupiter. We know today that its architecture was quite problematic, and in particular its "poultice" cylinder head was so poorly cooled that it did not resist the slightest overheating.

But by the time Fedden managed to get his version of the Burt/McCollum system with air-cooled cylinders to work properly, 15 years had passed and it is questionable whether Ricardo's arguments are still relevant at this time.
 

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there was a several page article in Flight by Fedden from 1938 (?) that I went through a number years ago on this site. Even at that time Fedden was listing all of these "benefits" over poppet valve engine problems that have been solve years before.
Comparing a 1938 Perseus to a uprated 1932-33 Mercury may have sounded good. Unfortunately the world market place was no longer the early 1930s Bristol radial engines. The World market place was P&W Hornets and Twin Wasps and Wright Cyclones. Countries around the world were buying licenses for American engines and not Bristol engines. There were a number of factors for this but Fedden and Bristol had sunk too much money and time into the Sleeve valve project and nearly bankrupted the company. And the Bristol poppet valves were severely out of date.
Things like absence of external oil lines. Maybe there were a few external oil lines on the American engines but they had stopped using grease guns to lube the valve gear several years earlier. The valve gear was enclosed and feed from the engine oil. So Perseus "advantage" was only an advantage compered to other Bristol engines. The list went on and on.

Somebody mentioned valves that were pennies or coins moved by nails?
When you use 146mm bore you are limited to valve size. You can use 4 valves to increase valve area but the shallow pent roof head does limit valve size.
The P & W Hornet used 155.6mm bore size and used a hemi head so there was more room to fit two large valves. Cyclone used the same bore size. I don't know if the valve size/area was equal but there were other ways of increasing valve flow without going to Sleeve valves.
In the late 30s the main problem with radial engines was cooling them.

We could go on for pages. The sleeve valve offered a lot of solutions in the early 20s. It offered very few solutions in the late 30s.
 
Shortround6 said:
Countries around the world were buying licenses for American engines and not Bristol engines.
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In think in 1937 -1938, this was not yet true. One of the most widely licensed engine in this period - two or three years before war - was the Gnome-Rhône 14 K.

And in 1951/1952, when French government wanted to have SNECMA license-building a 1500/1800 hp engine for the Noratlas, what did they choose ? Bristol Hercules !
 
Russians licensed just about anything they could, including the Wright Cyclone and the Gnome-Rhone 14K, last Bristol engine they licensed was the Jupiter?
Speaking of the Jupiter, it was that engine that was licensed to Gnome-Rhone in 1921 that lead to the later Gnome-Rhone engines (with a lot of modifications)

Some of the Japanese engines trace back to American engines.
BMW Licensed the Hornet.
A lot to this predates 1937-38.
Britain's lead in aircraft engine design was fading a bit in the 1930s.
Some of the Italian engines trace back to 1920s Jupiter engines.

I have no idea of why the French did what they did in 1951/52
Maybe P&W wanted too much for the license?
Maybe Bristol offered a below market deal?
Maybe the French government at the time was pissed at the Americans?
British and French were still trying to payoff war debt and figured it was better to by from each other than give money to the Americans?
There were all kinds of reasons why things happened, most of the them had little to do with what was "best".
 
I didn't avoid mentioning it. The rating of 3050 hp is what Ricardo wrote in his book, as I quoted in post 111. I have never claimed the max power rating was anything other than 3050 hp.
I saw no reason to bring up E122, as it was never run.
 

Yes, the 7K / 9K and 14 K engines owed some details to their distant ancestor the Jupiter - or more precisely, to the Jupiter's little brother, the Titan. They also integrated some features already seen at Armstrong-Siddeley, but also many (and mainly) things designed in France.

In addition to USSR, they were licensed in Italy, Belgium, Czechoslovakia, Hungary, Portugal, and Japan - Kinsei owes many details to 14K, starting with its valve gear. And even more, in UK (Alvis).

Finally, most of the European Jupiter licenses were Gnome-Rhone licenses and not Bristol. In fact, the French firm had converted the engine to metric standards which were current throughout the Continent.
 
Simon Thomas said:
Please show me where I trashed your book.
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You stated that having read it you "knew" that I would make negative statements about sleeve valves, implying that the book is a result of my bias, instead of what the reality is, which is that the book is simply a large collection of faithfully reprinted letters from the time showing exactly what was said at the time.

Some people asked things like "you know if you had just paraphrased those letters instead of typing them all out at such length word-for-word you could have made the book 1/3 the size." The reason I didn't cut out the letters was to avoid things like this thread happening.
 

Unfortunately, NPH attempt to promulgate some very peculiar ideas, which show a lack of understanding on 1st principles.

For example, on their site, the (patently ludicrous) claim is made that Napier developed their annular radiator program - partly due to
the chin/beard type of radiator on production Hawker fighters having the propensity to dig in & flip the aircraft 'A-over-T', in the event
of a wheels up/belly landing! As if ~5 tonnes of Typhoon or Tempest would be tossed by a mere radiator matrix/light Al scoop!

Of course, the radiator/fairing panels were wrecked, (unlike the annular set-up) but NPH has failed to revise the error, in spite of having
been advised of the nonsensical nature of the claim & its consequential stain on NPH's credibility.

It is also worth noting that, given the shambles made of Napier documentation post the early `60s R/R 'razor gang' sweep through Acton,
(after the UK Govt preremptorily 'merged' Napier to R/R - subsumed/scuttled - are closer to what occurred), that conflating existing/known
records - with somehow having authoritative knowledge - is unrealistic...
 
The NZ aero-maintenance crews responsible for fettling their post-war Hercules - eventually got a 3,500hr TBO from them,
not too shabby for a ~2,000hp radial of moderate cubic capacity. (& they appreciated the relative advantages of the sleeve-valve,
with no pushrod OHV chattering/leak-prone/clearance-checking/recip-action thrashing - demands to chase up).

Edit: Another thing to beware of, is conflating design/tested performance with poor production manufacturing & politico-economics,
to present these machines as mere 'show-ponies' at best, or 'hopeless dogs/waste of space-time' at worst...
(As anyone who bought a Sony Betamax, back in day - can attest)
 
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I copy pasted this into Google Translate and it said:

"I am too embarrassed to admit I made a mistake"
 
There still were (& are) a number of those advantages - which are inherent mechanical attributes - remaining relevant, as it happens.
 
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