Designation	Compound launch
Bore	1 inch
Stroke	7/8 inch
Configuration	Vertical twin cylinder compound
Height	5 1/2 inches
Length	5 1/4 inches
Extra equipment	Drain cocks Displacement lubricator Reversing gear
Taps required	2, 5, 7 BA 5/32, 3/16 x 40 tpi 1/4 x 32 tpi 5/16 x 26 tpi
Notes	Designed for model boats 54 to 72 inches long. The compound launch has a theoretical advantage in efficiency over the single expansion version, but at the expense of having dead centres making it non self-starting.