Top three photo's.
Here's a beautiful example of a A-7A Hall-Scott Airplane Engine. This one sits in the Pima Air & Space Museum in Tucson, AZ. and we want to thank them for sending these photo's to us and allowing us to put them on our web site. Their Museum should be on your list of places to go and visit.
The A-7A Airplane Engine: Four cylinder, vertical 100 H.P. 5 1/4 " bore & 7" stroke, approx. 824.7 ci. Named one of the "Big Four"
Hall-Scott recommended the use of their side type radiators and the "Albatross" type exhaust manifolds. ( Not shown in above photo's). Other types of exhaust manifolds were avalible.
The carb and intake manifold were heated from the exhaust manifold, with both water and oil jacketed manifolds. Hall-Scott had decided that this helped in obtaining the most power in the engine.
Two Dixie Model 481 Magnetos, made by the Splitdorf Electrical Co. came standard on all Big Four engines. The carb was a Model L-8 Zenith, single float, single air intake or a "Miller"
The engine weight is 405 lbs.
On a test card dated, Feb. 27, 1917 after an average of six running hours the engine produced 111 H.P. at ave. 1361 rpm. and 428 torque lbs, ft. This test was conducted by Hall-Scott with the Signal Corps, U. S. Army overseeing and was checked as "Satisfactory"
The patent for this engine was filed Dec. 14, 1917 by Mr. Hall and included 11 pages of discription and drawings.
The other "Big Four" engine was the A-7, 90 H.P. Other variants of the A-5 (introduced in 1915) which the A-7A is from, are A-5a and A-7, the first were A-1, A-2, A-3, A-4.
We know from manuals and records found that these engines were in U.S. Government Primary training bi-planes and some were used in the Dutch East Indies training planes.
Records also show that Russia purchased 300 of the A-5 or A-5a in or around 1910.
The A-7 or A-7a was the best selling engine Hall-Scott made up to 1918 at 2,250 engines made and sold not only by Hall-Scott but by Nordyke & Marmon a auto maker, which paid Hall-Scott $300.00 royalty per engine, under license.
For the war years of 1917 & 1918, Hall-Scott's net earnings were $1,737,759 and $2,638,307.
Pretty impressive earnings by any standard for any company in that time.