Desktop aircraft engines?

[Nick]

My friend Alan, who was an aircraft engine maintainer during the 60s/70s, is now asking me about model engines. He says he has seen small (fist sized?) engines for display on desks and shelves.
In particular he's after the Pratt and Whitney R-1820 or 1830 as used on C-47 Dakotas as he worked on those.

Does anyone have any ideas where we might source such a thing?

[jcf]

Monogram did an R-1820 Cyclone in 1/12 in 1959 that was last released by Revell in 1991.
Here's one on eBay for $59.95(USD):
http://www.ebay.com/itm/VINTAGE-1959-MONOGRAM-1-12-WRIGHT-CYCLONE-RADIAL-AIRCRAFT-ENGINE-w-BOOKLET-/311650642355?hash=item488fd369b3:g:JmwAAOSwhOVXfF0z



Otherwise Williams Bros. made/makes a Wasp and a Whirlwind in various large RC scales (1/4, 1/5, 1/6, 1/8 etc.), but no R-1830.

http://www.hobbylinc.com/htm/wbr/wbr30710.htm