Harold E. Morehouse worked at McCook Field for the US Army from 1920 to 1925. During this time he designed an engine with two horizontally-opposed cylinders.

-He has designed engines for several major American engine brands, such as Wright, Lincoln, Michigan Aero Engine Corp, Continental, Erco y Lycoming.

-The M-42 was a small Morehouse two-cylinder engine that gave 20 HP at 3,000 rpm. In the year 1924 it was tested at McCook Field.

-For Wright he made an horizontally-opposed cylinder engine, which became known as the Wright-Morehouse WM-80.

-It had two cylinders and gave  28/30 HP at 2,500. After he sold the rights to Lincoln this engine was offered as the Lincoln Rocket.

-While he was at Wright he was involved in the development of the J-5, the V-1456 and the J-6.

-In 1929 he entered Michigan Aero Engine Corp where he made the inverted four-cylinder Rovers.

-In 1932 he went to Continental, there he made the A-40, the O-1430 and began the development of the A-50.

-At Erco, since 1937, he started the inverted inline four-cylinder engines. Finally he enters Lycoming to make the O-235, O-290, O-350, O-435 engines and works with a team for other models.

-The WM-80, later known as the Lincoln Rocket, was a two-cylinder from 1925.

“Morehouse WM-80, front view”

“WM-80, top view”

-The WM-80 displaced 80.1 cubic inches with a compression ratio of 5.1 to 1. Power was delivered at sea level at McCook Field.

-Power can be described in more detail as follows:
-24.0 HP at 2,050 rpm.
-24.8 HP at 2,100 rpm.
-26.0 HP at 2,200 rpm.
-27.2 HP at 2,300 rpm.
-28.3 HP at 2,400 rpm.
-29.1 HP at 2,500 rpm.
-29.6 HP at 2,600 rpm.
-29.8 HP at 2,650 rpm.
 

“WM-80, side”

-Harold E. Morehouse's engine presented in diagrams is the WM-80. Now we present the M-42 here in new photographs. (See also Wright-Morehouse).

“M-42 rear part”

-It seems that the M-42 was the first engine designed by Morehouse, back in 1923, and was built by the Steel Products Engineering Co. (See).

“M-42 nearly front view”

-The M-42 had two horizontally-opposed cylinders giving only 12 HP at 2,000 rpm.

-The WM-80 was made at Wright Aeronautical, when Harold went over to that company with his model.

-He sold the rights to Wright. They were more powerful, giving 28 HP at 2,500 rpm.

“Wright-Morehouse WM-80, front view”

“Wright-Morehouse WM-80, rear view”

-We see one magneto, therefore the ignition is simple.