Some of you may have come across references to this enginefrom the late 20's, for those who haven't; it is basically a four cylinder radial using a double lobed cam instead of a crankshaft. The benefit was twice the torque as each cylinder went through its complete four strokes in one turn of the output shaft. And very simple cam gear. Pictures showing it on the front of a Waco show a giant prop, dwarfing the engine, about 10ft in diameter. It was rated at 150 HP.
Now, it did suffer from from torsional vibrations, from what I understand.
Looking at the design it would seem far superior to a conventional engine for our purposes, everything can be perfectly balanced and there would be no out-of-whack (that's a technical term summarising free forces of the 1st,2nd and 3rd order...) forces to contend with. Everything that moves has an opposite number moving the opposite way.
So why did it rattle like it did? Seems to me the torque diagram would be pretty smooth with four cylinders firing evenly once every revolution, certainly no worse than other engines. Perhaps the cam profile could have been improved? Maybe that 50 lbs prop had something to do with it?
If there are any resident boffins I would like their opinion on this; it seems like such a splendid idea I'm thinking of buying a lathe tomorrow and start making my own version! (But mine would be a two stroke diesel with an air start sytem and free floating pistons-no link rods required- ah where are the napkins and crayons?)
Now, it did suffer from from torsional vibrations, from what I understand.
Looking at the design it would seem far superior to a conventional engine for our purposes, everything can be perfectly balanced and there would be no out-of-whack (that's a technical term summarising free forces of the 1st,2nd and 3rd order...) forces to contend with. Everything that moves has an opposite number moving the opposite way.
So why did it rattle like it did? Seems to me the torque diagram would be pretty smooth with four cylinders firing evenly once every revolution, certainly no worse than other engines. Perhaps the cam profile could have been improved? Maybe that 50 lbs prop had something to do with it?
If there are any resident boffins I would like their opinion on this; it seems like such a splendid idea I'm thinking of buying a lathe tomorrow and start making my own version! (But mine would be a two stroke diesel with an air start sytem and free floating pistons-no link rods required- ah where are the napkins and crayons?)
