Radial Engine Question?

While the Taurus had a lower power rating than the Hercules, it was much smaller in diameter and lighter than even the Twin Wasp.

Why not use this for FAA fighters?
Give it a two speed supercharger and you will gain performance at altitude.
However...
The 29.8in by 41.2 in Merlin facing easily beats the 46.25 in diameter Taurus.

The Taurus could have been a very good engine. The work done de-bugging it went into the development of the Hercules and Centaurus. It had a good power to weight ratio and could eventually have produced as much power as the similar displacement Merlin. At 44" it was 10" less in diameter than it's big brothers so the drag penalty would have been less. Also as I mentioned radial engines had their strengths such as no vulnerable radiators and unless the bottom cylinder was shot off letting all the oil out they could keep going when bits were knocked off them.

So I think to answer Landys original question the Hercules would be fine for a twin engined fighter but it would have been better to develop the Taurus for a single engined aircraft.
 
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I think that, like my wallet, there isn't much in it. The Hercules has the advantage that it was built in large numbers unlike the Taurus, so development costs and effort could be spread over a larger spectrum of aircraft. If the Taurus gets developed what else will it be put into?
 
Let me quote Hal Dantone Director of The Aeronautics Company...
The question is not efficiency but achievable top speed. In the 1930s it was believed only in-line engines could achieve the speed needed. But what actually happened was radials were always able to keep up with top speed because they were always ahead in raw power. This lead became massive by the end of the war.

Look at the fastest fighters of the war, many were radial engined fighters. The Sea Fury, the P-47N, both were as fast as the best in-line fighters. Raw power does the job. These big engines lead to greater weight, which means better dive speed. Not to mention the superior maintenance, mission readiness, and survivability of radials... much more relevant than pure aerodynamic efficiency.

As for Hercules vs Taurus. The latter is a smaller version of the former. Yes the Taurus is smaller and lighter, but it's also less powerful. It's not a question of which is the "better" engine but which aircraft you need it for.
 

perfectgeneral

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Monthly Donor
I think that, like my wallet, there isn't much in it. The Hercules has the advantage that it was built in large numbers unlike the Taurus, so development costs and effort could be spread over a larger spectrum of aircraft. If the Taurus gets developed what else will it be put into?

The question is not efficiency but achievable top speed. In the 1930s it was believed only in-line engines could achieve the speed needed. But what actually happened was radials were always able to keep up with top speed because they were always ahead in raw power. This lead became massive by the end of the war.

May I refer you both to my previous post?

The 29.8in by 41.2 in Merlin facing easily beats the 46.25 in diameter Taurus. It might do for a carrier capable Miles M20 fighter and a Hawker Henley dive/torpedo(just) bomber though.
Henley
navhen.JPG
300px-Miles_M.20.jpg
M.20
OTL the Fairey Albacore torpedo bomber, Battle and the Beaufort used the Taurus engine. The Gloster Reaper or their F.5/34 would have been a good use for it too.
Prototype Fury
LA610 was eventually fitted with a Napier Sabre VII, which was capable of developing 3,400-4,000 hp (2,535-2,983 kW). As a result it became the fastest piston engined Hawker aircraft, reaching a speed of around 485 mph (780 km/h).
More directly to your point:
Sabre Production
Development continued, and the later Sabre VII delivered 3,500 hp (2,600 kW) with a new supercharger; the final test examples delivered 5,500 hp (4.100 kW) at 45lb/sq in boost. By the end of the war there were several engines of the same power class; the Pratt & Whitney R-4360 Wasp Major was producing about 3,055 hp (2,280 kW), with almost twice the displacement, 4,360 in³ (71 L).
 
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Look at the fastest fighters of the war, many were radial engined fighters. The Sea Fury, the P-47N, both were as fast as the best in-line fighters. Raw power does the job. These big engines lead to greater weight, which means better dive speed. Not to mention the superior maintenance, mission readiness, and survivability of radials... much more relevant than pure aerodynamic efficiency.

Very true. The capabilities needed in an effective military airplane are quite different from those of a dedicated racer: you need space to put in weapons, armour and a lot more fuel than a plane that merely needs to go through a 8.5-mile course once or twice.
 

perfectgeneral

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Monthly Donor
The Napier Sabre powered MB3 had six 20mm cannon.

I have to agree about the rugged nature of the radials.

Originally Posted by tallwingedgoat These big engines lead to greater weight, which means better dive speed
Don't let the physicists on these boards 'hear' you 'saying' that. Remember that a feather falls as fast as a hammer in a vacuum (or held in an identical shape. Hint, hint).

Back on topic, how about a Taurus powered MkII Westland Whirlwind?
 
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Very true. The capabilities needed in an effective military airplane are quite different from those of a dedicated racer: you need space to put in weapons, armour and a lot more fuel than a plane that merely needs to go through a 8.5-mile course once or twice.

The Mustang has ALWAYS been voted the best single seat, single engined fighter that had the greatest impact on contemporary events and it didn't even use the most powerful engine, ie. the Griffon, that it could have. Anyway doesn't everybody know radial powered machines, warthog ugly:rolleyes:

0710013_7.jpg
 
Getting really sick of this argument, why do they bother with wind-tunnel testing if frontal area and drag are not major issues in designing a vehicle on land, sea or air? :confused:
 
The Mustang has ALWAYS been voted the best single seat, single engined fighter that had the greatest impact on contemporary events and it didn't even use the most powerful engine, ie. the Griffon, that it could have. Anyway doesn't everybody know radial powered machines, warthog ugly:rolleyes:

Right clicks and slects "Set as background".

Why couldn't we have had the Sea Fury in 1943!?! And why did they scrap all the De Haviland Hornets!?!
 
Getting really sick of this argument, why do they bother with wind-tunnel testing if frontal area and drag are not major issues in designing a vehicle on land, sea or air? :confused:

(1) Frontal area isnt quite the same thing as drag. In any case, that particular issue is quite easy to model.

(2) Wind tunnel testing is mainly concerned with stability and aerodynamoc response issues
 
What would be interesting in the whole radial engine area is if Feddon had not paid as much attention to Riccardo and had also looked at double rowing the poppet valve engines.

'A further factor was that back in 1922 Harry Ricardo had said that the poppet valve was nearing the limit of its development.'

'With hindsight, we can see that Riccardo's belief that the poppet-valve was nearing the limit of its development was nonsense. New materials for exhaust valves and their seats, and especially the introduction of sodium cooling, greatly raised the limit on what could be achieved.'

Then Bristol may have been able to offer Hercules power sooner than it did with sleeve valves.

Sodium cooling was introduced in 1929 and it seems Gnone ran a twin row adaption of the Mercury then.

http://en.wikipedia.org/wiki/Gnome-Rhône_14K
 
Nice Sea Fury!

Sorry Dean, despite your good points I can't write off the radial as a fighter engine, there were too many first class aircraft produced with radials.

PMN1, at the time Ricardo was probably right, in the 30s the poppet valve didn't have the development potential of the sleeve valve. But there's no discounting industrial interia, poppet valve engine makers made a comeback with exotic things like sodium valve stems. But the point is that poppet valve engines were regularly much larger than sleeve valve engines of similar power. I think that if the US had a major manufacturer of sleeve valve engines, and these engines were put into a mass produced US aircraft we'd be pointing out how good sleeve valves were.
 
What would be interesting in the whole radial engine area is if Feddon had not paid as much attention to Riccardo and had also looked at double rowing the poppet valve engines.

'A further factor was that back in 1922 Harry Ricardo had said that the poppet valve was nearing the limit of its development.'

'With hindsight, we can see that Riccardo's belief that the poppet-valve was nearing the limit of its development was nonsense. New materials for exhaust valves and their seats, and especially the introduction of sodium cooling, greatly raised the limit on what could be achieved.'

Then Bristol may have been able to offer Hercules power sooner than it did with sleeve valves.
...
Sleeve valve engines were very cool though. It consistently had smaller engine diameter for the same power. Not to mention the maintenance benefits of not having all those poppet valves to look after.

The Bristol Project 153 was a single Hercules engine fighter. It should have been quite good if developed.
 
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