ADVANCE


| July/August 1972



2/5 scale model Advance engine

2/5 scale model Advance engine owned by Ross Naylor, Platt City, Missouri. Courtesy of Ernest H. Casson, 909 Naperville Road, Wheaton, Illinois 60187.

Ernest H. Casson

909 Naperville Road, Wheaton, Illinois 60187.

A 2/5 Scale Model Advance Steam Traction Engine Built in 1961 by the Owner, Ross Naylor, Box 111, Platt City, Mo. It is his No. 1 engine.

Boiler description; Locomotive dry bottom firebox type, shell 15'Dia. 60' long, seamless, 141' tubes 32' long, firebox 12' wide, 15' long, 14' grate to crown sheet. Boiler hydrostatic tested to 225 lbs. design steam pressure 150 lbs. and operating pressure 150 lbs. Heating surface 23 Sq. Ft., Grate surface 1.3 Sq. Ft., furnace volume 1.51 Cu. Ft. The boiler will produce, when burning 46 lbs. of dry wood per hour having 8500 Btu. per lb. with 60°F. feed water temperature, 150 lbs. steam pressure at 68% boiler efficiency, 228 lbs. of steam per hour.

Engine description; a single cylinder simple, 4' bore, 5' stroke, 'D' slide valve, Marsh valve gear and reverse with cutoff at 6/10 stroke, 225 RPM. on governor control on belt or traction work. At 101.3 psig., (lbs. per sq. in.) MEP. and 225 RPM. the engine will produce 71 HP., (indicated horse power). At the same conditions with 79.9% engine mechanical efficiency it will develop 5.6/H. P. at the flywheel rim.

The engine traction system is a two shoe band or flywheel clutch, a 22 tooth crankshaft pinion, a 68 tooth intermediate gear, a 68 tooth differential spur gear, 12 tooth countershaft pinions, 80 tooth bull gears, and 2'-6' Dia., by 9' rim drive wheels. The engine with fuel and water supply weighs 2,000 lbs. The ratio of engine RPM. to drive wheel RPM. is 10.92 to 1. The road traction speed at 225 Rpm. engine speed is 0.975 MPH. The horse power delivered to the drive wheels is 2.9 equal to a gross tractive effort of 1,115 lbs. The net drawbar horsepower when the engine is traveling at 0.975 MPH., on a light clay stubble field is 807 lbs., equal to 2.1 horse power.

Engine construction features through the courtesy of Mr. Ross. Engine performance calculations by Ernest H. Casson.