My reason for the switch from alcohol to butane was twofold. First the butane system uses less room allowing the installation of a minimal RC system. Secondly the alcohol firing system is dependent in large part on stack air movement to coax the fire into the boiler area. That means either the blower must be run without stop, or the engine must be run at a relatively high RPM to use exhaust steam to create draft. I wished to do neither, blower use meant another servo, and high speed engine running meant high speed engine movement, one of the things this engine is criticized for. By having a heat source under the boiler not dependent on draft, I can concentrate on the other variables.
As I am old, and my empire is ground level with plantings, not an elevated oval, I need RC to control the engines on grades and with varying loads.
Lest one think that Aster never makes mistakes or "design errors" I beg to differ, Thier roster has a number of less then stellar performers. I have 3 Aster engines, one, the Climax, has a steam pick up inside the boiler which causes the engine to run "wet" unless the boiler water level is kept well below the 3/4 full mark. A simple steam dome design would have corrected this problem.
