Piston engine deisgn

The radial engine evolved by putting more cylinders on to smooth out the power stroke, and putting more banks or rows or cylinders to increase the power and capacity, eventually having to use liquid cooling rather than air cooling due to the difficulty in cooling the rear banks of cylinders.

Hence the early and inefficient 2 cylinder “V” radial evolved to being a 2 cyl, 6 row engine with liquid cooling, as the ultimate development of the radial engine:diablo:

smiles

Mark Pilkington

Mark, you seem to be describing an inline engine, the main clue being that a ‘radial’ works best with an odd number of cylinders.
Ray

The best example for such a switch from radial to inline is that of the Fw190A series to the Fw190D series and Ta152. The definitive answer to the question of single-engine piston fighter design. One thing to keep in mind is that a V-12 is pretty much maxed out around 40 litre volume, delivering about 2500PS up to 12000m (4-valves, three-gear two-stage superchargers with intercooling, water/methanol or N2O injection, shaped exhaust nozzles).

It seems like there were more than a few occasions where substituting a radial engine for an inline produced a superior airplane. The ki 100 comes to mind. I think you could also argue the Typhoons were better with the Centaurus than the Sabre.
Could the radial be improved? How about using magnesium cooling fins like the BMW 801 and direct fuel injection, removing the mechanical supercharger entirely and going with turbo-charging only, four valve heads. What else? Maybe maximize oil cooling? Shrink the entire engine diameter as much as possible. Could an 18 cylinder radial of about 2000 cubic inches produce 2000 reliable horsepower?
Look at the state of modern air-cooled motorcycle engines. 4 valve heads air-cooling and forced induction all live happily together in a microscopic package.
If not, what would a modern radial look like from a clean sheet of paper? I guess it could be liquid cooled but I’m not crazy about that.

This subject is infinitely more complicate than your simple analogies would suggest, and it is not true that the radial engine improved aircraft when it replaced an inline engine. My best suggestion is your read Allied Piston Engines of WWII by Graham White.
By the way the Typhoon was never powered by a Radial engine, only the Napier Sabre, an unashameably military engine. This 36 litre engine produced 2600hp on a regular basis during late war combats operations , and 3000hp was a possibility. The Centaurus produced 2500hp from 57 litres. Both were sleeve valve engines, again a technology developed to produce more power, and only persisted with. Both engines were difficult to fully develop and both suffered from vibration issues that were not present in earlier engines with fewer cylinders.

What would a clean sheet engine look like? Who knows, what is the role? And what are the key requirements. Maybe an air-cooled inline turbo diesel with common-rail fuel system and power recovery turbine. All off the shelf commercially available stuff.

The radial engine evolved by putting more cylinders on to smooth out the power stroke, and putting more banks or rows or cylinders to increase the power and capacity, eventually having to use liquid cooling rather than air cooling due to the difficulty in cooling the rear banks of cylinders.

Hence the early and inefficient 2 cylinder “V” radial evolved to being a 2 cyl, 6 row engine with liquid cooling, as the ultimate development of the radial engine:diablo:

smiles

Mark Pilkington