nice jon , if anyone wants look at a real 3420 allison they have one on display at Fantasy of Flight in Florida.
also the best aircraft engine display there also!
Mercedes 605 invertid V12.
and of course because i love engines,all kinds , when in Daytona fl. i did maintenence on a boat that had the twin GMC 6-71 engines coupled together with a huge gear box, out one propeller shaft!
boat had 4 engines , but 2 prop shafts, originally made for WW2 landing craft. they were counterrotating units.
if for some reason an engine failed you could manually disconnect it with a clutch and run on a single engine!
very kool idea,
WW2 was a fasinating time , shame so many people died ,while we spent billions on making equipment to kill them!!
Robros expressed his opinion that Brits thought their stuff better than anyone else’s stuff. Mebbe so and mebbe not on two levels? I don’t see any thing wrong with expressing an opinion and certainly not an insult???
The PT boat engines were Packard Marine V12’s. beautiful design and execution. Each boat got three. I’ve read of restorations of the boats and the rehabbing of the engines. Love that stuff.
Indeed, I messed around with water injection. The crude critter hangs on my shop wall. Tried not only water, but, added alcohol. Results unknown. I did not come up with a way to detect any improvement.
As built, mine involved manifold vacuum. Highest at idle or cruise. Not where it could best assist combustion sans ping!
I messed with a micro switch at the throttle of my FJ40. It to charge a windshield washer pump and inject on throttle application. Tine phasing and volume issues not resolved. I feared a hydraulic lock if I squirted in too much.
In about 56, I decided the B & S on my lawn mower would do better with more power. Reel type and as such a horizontal shaft engine. So, I stripped it down and ported it, intake and exhaust.
It seemed to work ??
When the mower just plumb wore out, the B & S was fine. I kept it.
Son now old enough to get wheels. Xmas bought a pedal car. A tubing version, not the stamped steel variety. He did great on the pedals driving the rear wheels via a chain.
Against wife’s concerns, I decided to mate the B & S to the cart. Belt drive in this application. Pressing a pedal tilted the engine and took the slack out of the V belt drive. Oh, oh, works too well, too much speed. Oxymoronic? Sorta. So, I “detuned” the
B&S. Just turned the mixture screw to richen the mix. Lopey and smokey, yeah, But son delighted.
I felt better as did wifey. Daughter, not so much.
He faster than she on her leg powered trike!!!
As I can remember the engines were both mounted side by side…shafts entering a massive gear box and it would make sense that the props were counter rotating …nulifing the torque as power was increased.
Wikipedia is hardly a good source for suc h or nay information as you and I can post aNY THING WE WANT ABOUT ANYTHING…thasnks for the question Kirby…why not google Allison 3420 and see what turns up. I will see if I can locate a credibile source in the meantime as the 3420 had a lot of potential for ??? Best, JW I was told only 6 were built by a race engine engineer who has been building Gurney Eagle engines, Offys, etc. His latest little project a 11,000 hp mTHANOL…DRAG BOAT engine, will send you a pic some time , best, JW
Thanks Ron, I thought you had passed when you stopped posting on the jaglivers …you are still a great source and am glad to see you still have that great roadster, Best, JW