Merlin in 51 had a 2-1 gear reduction. 3000 rpm gave 1500 rpm prop
speed as I recall.

Big John



On Tue, 25 Nov 2008 19:29:06 -0800 (PST),
wrote:

On Nov 25, 7:47 pm, wrote:

Lycoming has made several geared engines over the years and none has
been particularly successfull. I believe the Merlin (or one of the
big "V" engines) was also geared.

Both the Merlin and Allison V-12s were geared. And most of the
big radials were geared. It was one of the few ways to get more
horsepower out of a given displacement.

R-1830 radial cutaway, with gears in the front of the case:
http://aviatechno.free.fr/vilgenis/i...830_02_730.jpg

Merlin cutaway: http://www.thunderboats.org/history/...tory0324_1.jpg

Common geared Lycs: GO-435 and GO-480. Continental had the GO-300 and
GTSIO-520.

Daimler Benz DB601a: http://www.aviation-history.com/engines/db601a-1.jpg

Geared engines are nothing new at all.

Dan