Air Speed Record for piston powered seaplanes

herman1rg said:

What's needed is a Modern day equivalent of Howard Hughes with plenty of money

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Well I put forward Elon Musk, the South African Engineer who became a Billionaire through founding PayPal and has now funded Tesla Motor as well as Space-X. Or what of Richard Branson with his funding of Scaled Composites and its Virgin Galaxy sub orbital aircraft. There is the software billionaire who had a couple of Me 262 built (apparently was insisting on recreated Jumo 004 engines at one point) also a few round the world solar aircraft will be of on a flight soon.

BobR said:

I came across these posts while checking what had been spoken of here in the past.

As far as enthusiasts and speed records, yes, desire is the only real thing driving it along.
Approx. twenty years ago there were few, to the point of one or two, cars running that were even in the 300 mph range in the U.S.; now there are enough cars breaking 400 mph that for U.S. sanctions new categories were created so a 400 mph run was not discarded because it did not break the record properly.

With today's more advanced knowledge of air-frame construction, and CNC metal machining abilities a cleaned up and faster sea-plane's only difficulty in setting a new record is probably not cubic-inches but a lack of cubic-dollars.

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But what's the age group of these mechanical inclined competitors? Most of the hobby engine people I know are grey beards. The youngsters are more interested in virtual than real. This is an observation not a complaint. Times change and there's not all that much not already known –or needed- with regard to piston aircraft.

The article says the weight of the AS6 was 2,045lb, with weight/power ratio of 0.706. According to Wikipedia, the weight of the Rolls Royce R type is 1,640 lb and the power in world record tune 2540 hp, giving a weight/power ratio of 0.65. So the AS6 was a bit of brute-force effort. In addition apparently the R type was cleared to 2783 hp for short bursts, but the S6B airframe could not take the extra power.

I'm always struck by the contrast between the use the British made of their Schneider Trophy work (Spitfire, Merlin, Griffon, all critical for the British air war effort) and how the Italians did nothing with it.

The Schneider Trophy work that RR did actually did little or nothing for the Merlin directly. Indirectly it gave them a lot of experience in problem solving while working to tight deadlines. It may have given them some materials experience.
Since all the later Schneider Trophy racers used some rather exotic fuel blends that had little to do with actual aviation gasoline some of the engine experience didn't carry over that well. Getting an engine to survive that power output did carry over.
Since the racing was done at sea level high altitude performance had little to do with anything.

ktank said:

I'm always struck by the contrast between the use the British made of their Schneider Trophy work (Spitfire, Merlin, Griffon, all critical for the British air war effort) and how the Italians did nothing with it.

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The same thought would apply to the Curtiss D-12 that was pretty much the seminal water-cooled V-12.

Not really, the Curtiss D-12 was a very good engine in it's day but it's day had passed. For instance it used a narrow bore (4.5in) and long stroke (6.0in) for it's size and weighed about 700lbs. Stroke was the same as the Merlin and Allison. A number of it's features were copied and other companies went on to make more advanced engines. I am not sure if the 1923 Schneider Trophy engines used special fuel or ran on normal gasoline. The engines were un-supercharged.

Shortround6 said:

Not really, the Curtiss D-12 was a very good engine in it's day but it's day had passed. For instance it used a narrow bore (4.5in) and long stroke (6.0in) for it's size and weighed about 700lbs. Stroke was the same as the Merlin and Allison. A number of it's features were copied and other companies went on to make more advanced engines. I am not sure if the 1923 Schneider Trophy engines used special fuel or ran on normal gasoline. The engines were un-supercharged.

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Agreed that the 1923 D-12 was a 1920s engine. But it won the Pulitzer races, the Schneider Cup and set the world speed record for seaplanes. Continued improvement and updated technology over 15-20 years might have led to the US Merlin. But, like the Italians, early success was not built upon.

The one thing the Curtiss D-12 did do was spur Rolls into proving they could build a better engine, the Kestrel. The D-12 was examined in Britain, but importantly, its immediate impact was more dramatic. 50 examples were purchased and shipped to the UK for use in the Fairey Fox single engined day bomber, in which the D-12 engine was named the Felix. The Fox is one of those unsung aircraft that quite literally turned the establishment on its head. Built using private funding and without official sanction, it was faster than the fighters of its day, being more streamlined and made the aircraft built to the official specification look ponderous and incapable. This was the Fairey Fawn, built by the same company, but constructed to the requirement laid down by the Air Ministry:

https://en.wikipedia.org/wiki/Fairey_Fox

The Official aeroplane, the Fawn:

https://en.wikipedia.org/wiki/Fairey_Fawn

Despite its promise, in typical British scorn, the marvellous Fox was not built in very large numkbers and equipped only one RAF squadron, 12 Sqn, whose motto "Leands the Field" and foxes' head badge are as a direct result of Marcel Lobelle's fast bomber of the 1920s.

https://en.wikipedia.org/wiki/No._12_Squadron_RAF

Balljoint said:

Agreed that the 1923 D-12 was a 1920s engine. But it won the Pulitzer races, the Schneider Cup and set the world speed record for seaplanes. Continued improvement and updated technology over 15-20 years might have led to the US Merlin. But, like the Italians, early success was not built upon.

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It was an 18.8 liter engine, it was only going to go so far. It lead to the Curtiss V-1570 Conqueror (a 25.7 liter engine) which was built for at least six years and ended with a run of over 50 turbo supercharged engines. It lead Packard to design and build the 24.5 liter 1A-1500sereis of engines (not really a success) and Packard went on with the 40.8 liter V-2500 series engines which would up powering the vast majority of Allied motor torpedo boats. It spurred R-R to ditch their older separate cylinder engines (Falcon, Eagle, and Condor) at start a new series with the Kestrel. I would say it didn't have that bad a legacy.

The D-12 was a tremendous improvement over the Liberty V-12 (and might have made a better tank engine) but engines designed to run on 40-50 octane fuel NEED so much improvement that at some point you might as well start over. Again, please note that the basic engine was smaller and lighter than the Kestrel, the Jumo 210, the Hispano 12X series (not 12Y series).