Ad: This forum contains affiliate links to products on Amazon and eBay. More information in Terms and rules
J.A.W. you are not a fool so why act like one, the sleeve valve had merits and de merits, the aviation industry decided the de merits were more important. Peak horsepower is one issue, reliability and serviceability is another.No SR6, I am not the one missing the point, the sad fact about British politico-industrial leadership
& organisation being so inept in many instances - is a different subject from engine design merits.
& here is a service trial of a sleeve-valve powered machine from late `41:
http://www.wwiiaircraftperformance.org/typhoon/Typhoon_AFDU_Tactical_Trials.pdf
Performance figures well in advance of any other contemporary service test machine.
& despite the well documented shambles that accompanied the Typhoon in 1941-43,
a comparison with the F4U shows which of that pair reached its design goals 1st.
P pbehn , here is Roy Fedden's list of sleeve-valve merits: http://www.flightarchive.com/pdfarchive/view/1941/1941 - 2830.html
J.A.W. you are not a fool so why act like one, the sleeve valve had merits and de merits, the aviation industry decided the de merits were more important. Peak horsepower is one issue, reliability and serviceability is another.
To increase performance from two row 18 cylinder, radial air cooled engines or V12s was not easy. Based on a maximum bore and stroke of 6inch the radial has the advantage because of 18cylinders but water cooling a radial is almost impossible.
By 1944 Rolls Royce could no more come up with a ready made air cooled radial design any more than Wright could produce a water cooled H or V format engine.
I read them, it is incredible how the links you post repeatedly point to reliability issues in almost every paragraph.Incorrect yet again, ben.. as the linked evidence - should you choose to avail yourself of it - shows..
I read them, it is incredible how the links you post repeatedly point to reliability issues in almost every paragraph.
The Typhoon/Tornado were supposed to be the spitfire/hurricane replacement as a high altitude inteceptor, after many years and three engines in many guises they managed it at low altitude only@ SY, I don't think so, many a time - engine-airframe are twofer deal..
Take the proposed Spitfire replacement - the Tornado, without the Vulture, it was a dead-duck.
unlike the Manchester which by accepting 2 Merlins for each Vulture, successfully morphed into the Lancaster..
& a Model A Ford, for all its value-for-$ practicality, wasn't going to whip an SSK Mercedes-Benz over 24hrs @ Le Mans..
That "period" being 1944 is one of your choosing, it was supposed to be sorted in 1941/42, but it needed a new engine, wings, fuselage, canopy and tail. The Typhoon was required as a top class all altitude fighter in 1942 but it lapsed into a ground attack plane with a radiator in 1944, the Tempest, when introduced in 1944 it was in a world of jets and rockets.Which just happened to be where the most useful 'trade' could be found, for ADGB in that period, too..
Are you really implying that the Hercules, which was in widespread service for much of the war, was significantly less reliable than its contemporaries?I read them, it is incredible how the links you post repeatedly point to reliability issues in almost every paragraph.
No, I was referring to all the links posted about sleeve valve engines by J.A.W. the Hercules seems to take a back seat behind the stellar performance of the Sabre and Centaurus.Are you really implying that the Hercules, which was in widespread service for much of the war, was significantly less reliable than its contemporaries?
So the mainstream use of sleeve valves during the war proved normally reliable, but the urgent development of the next generation of engine was problematical. Sounds pretty standard for engine development worldwide.No, I was referring to all the links posted about sleeve valve engines by J.A.W. the Hercules seems to take a back seat behind the stellar performance of the Sabre and Centaurus.
Not really because the Merlin replaced it in the area that it was supposed to be replaced, high altitude interceptor. The Napier Sabre sleeve valve was only marginally reliable in service, when you have to heat engines and "run them up" every few hours you need two maintenance crews, time between overhauls was 25 hrs at times. Engines with similar swept volume went on to power the worlds airliners, the Napier Sabre was retired ASAP and not sold to anyone. You could say that the Centaurus was more successful, but how many engine variants did the Typhoon Tempest have in the course of the war?So the mainstream use of sleeve valves during the war proved normally reliable, but the urgent development of the next generation of engine was problematical. Sounds pretty standard for engine development worldwide.
Retrospectroscope, much? Poppet valves for high-performance engines were saved by the development of high octane fuels. At the time when sleeve valves were being developed - the Hercules started development in 1936, I think - high octane fuels didn't exist. Sleeve valves were a pretty good way to get high performance from 87 octane fuel.The Sleeve valve engines were developed, as I have said before, into high powered, reliable and long lasting engines. It is just that they didn't offer that much of an improvement over the poppet valve engines of the same time. The millions of pounds invested in the sleeve valve never really paid off despite the gee whiz numbers posted by the last of the engines.
Not really because the Merlin replaced it in the area that it was supposed to be replaced, high altitude interceptor. The Napier Sabre sleeve valve was only marginally reliable in service, when you have to heat engines and "run them up" every few hours you need two maintenance crews, time between overhauls was 25 hrs at times. Engines with similar swept volume went on to power the worlds airliners, the Napier Sabre was retired ASAP and not sold to anyone. You could say that the Centaurus was more successful, but how many engine variants did the Typhoon Tempest have in the course of the war?
Retrospectroscope, much? Poppet valves for high-performance engines were saved by the development of high octane fuels. At the time when sleeve valves were being developed - the Hercules started development in 1936, I think - high octane fuels didn't exist. Sleeve valves were a pretty good way to get high performance from 87 octane fuel.