Sombart Model Engine Review

Enlarge Image Image Gallery Figure 1: A period print, complete with 'Sombart' misspelled, which illustrates the engine as it appears in the Young Mechanics Own Book, printed in 1897. The engine was designed for light work and was rated in terms of manpower.

Type: Sombart non-compression engine.
Scale:1/5
Maker: Wayne Grenning, Lockport, N.Y.
Availability: Casting and full material, kit, finished model.

The model reviewed this month is the latest offering from Wayne Grenning, the fellow who brought the scale model of the Otto-Langen into the world. Keeping in line with his first project, we are presented with a model of a prime mover from the past, the likes of which has never been seen before. The model in question is of a Sombart non-compression gas engine, manufactured under Bisschop patents, by the Sombart Mfg. Co., in Hartford, Connecticut. Figure 1 in the Image Gallery shows a period print, complete with 'Sombart' misspelled, which illustrates the engine as it appears in the Young Mechanics Own Book, printed in 1897. The engine was designed for light work and was rated in terms of manpower. (One manpower was about 1/12 HP). It was a non-compression engine, with open flame ignition, and used coal gas or illuminating gas as fuel. The model is scaled from a 5 manpower engine which is owned by Tom Stockton, of Ann Arbor, Mich. This is the only Sombart known to exist.

Its mode of operation is as follows: The piston starts at the bottom of the stroke, with the spool valve in a position to admit gas and air through large check valves. As the piston rises it draws in gas and air, and they are mixed in the valve chamber before entering the cylinder. About halfway through this stroke, the piston uncovers a flame port with a flap valve over it. Since the pressure in the cylinder is slightly below atmosphere, the flame at this port is drawn through the flap valve, and ignites the charge in the cylinder. This slams the flap valve shut, blows the gas and air check valves shut, and forces the piston to the top for the power stroke. The spool valve then shifts position via an eccentric on the crankshaft, and on the down stroke of the piston, the burned gases are expelled through the exhaust port at the bottom of the engine. Since the ignition of the charge usually blows out the ignition flame, it is equipped with an auxiliary flame to re-light the ignition flame.