tuj wrote:After doing some recent reading on torpedoes, I came across this engine design. I was really surprised reading about some of the engines' power output in early iterations along with relatively low weight. I started thinking that the swashplate engine has some real advantages, namely that its a barrel-shaped design generally which would make for good aerodynamics in a racecar.
I have read that the MK48 torpedo develops 500hp, not sure how heavy it is, but that sounds pretty good. I know it runs on OTTO fuel, so that's a little different than petrol, but still seems like an interesting design. I have heard that these engines were installed in airplanes as well, so they must have been at least somewhat reliable.
What are the draw-backs of the swashplate engine? I have seen designs that allow for variable compression ratio, so this seems like it could be especially beneficial for a racing engine, especially if coupled with forced-induction.
Thoughts?
Conventional crankshaft ICE engines are incredibly easy and cheap to manufacture, have low friction and work well with great performance, durability and huge speed range. 1000's of attempts to use other mechanisms to drive pistons over the last 100 years have all been abject technical/economic failures.
I worked professionally on a Z-crank engine for a couple of years. Bad idea. They are compact and perfectly balanced, but need spherical joints at each end of con-rod and a CV joint of some description to stop the 'spider' on the Z-crank (off which the conrods are mounted) rotating with respect to the cylinder block. These two mechanical details sink the idea due to the very high peak inertial and gas forces present in IC engines. Difficult to make lightweight high load spherical joints or CV joints (Well known Rzeppa type not suitable, need double Cardan joint or similar)
Swashplates for ICE engines are terrible as lateral forces and sliding friction losses are huge for necessary piston speeds. Even worse are the torpedo engine derivatives like Axial Vector, with pistons driven by bearings following cams - that induces huge lateral forces on the pistons and will destroy them if attempt to run at useful IC engine -relevant piston speeds for any length of time.
Swashplates are good for variable stroke small compressors and hydraulic motors/pumps with their low piston speeds where frictional power losses are low due to low sliding velocities.
