Delta Force
Banned
It looks like that engine was part of the USAAC Hyper Engine program of the 1940 timeframe
http://en.wikipedia.org/wiki/Hyper_engine
This was an attempt to get 1 HP per cubic inch
There are some interesting engines and aircraft listed in that article.
I don't necessarily know about power to volume ratios, but in terms of power to weight ratios wouldn't it be better to have a few large cylinders rather than many small cylinders? Volume scales exponentially relative to surface area (in this case, cylinder size), so it seems that from a purely mathematical point of view, the best design would take the largest cylinder capable of functioning properly (gasoline engines having a limit due to the need for spark ignition) and arrange them in a suitable configuration.
All of the multibank engines above the v type* were pretty much failures. It can't of been from excessive mass on the crank throws as evidenced by 9 and 18 cylinder radials. I think in the long run the Lycoming would of worked. The Tornado I have my doubts. The layshaft setup bothers me.
*By this I mean all of the 4 or 6 bank star configurations. I suspect there were vibration issues common to the type due to uneven firing orders.The Sabre was multi bank true. But it was a compound engine of basically two flat 12s
I haven't been able to find a source to really visualize this, but what's the difference between a multibank engine and something like an H, U, or W engine?