Lawrance (US)

Charles L. Lawrance (1882-1950) developed the Lawrance-Moulton Model A V-8 engine in France in 1913. He then formed the Lawrance Aero Engine Company of New York City and built the Model B V-8 during 1916-1917 along with the two HOAE listed here. After Lawrance's small firm had designed, built, and tested the A-3 (O-150), the Joint Army and Navy Technical Board purchased the production rights, jig, fixtures, dies and plans from Lawrance Aero. The Board then gave a production contract to the Excelsior Auto Cycle Motor Manufacturing and Supply Co. of Chicago, Illinois for 450-500 A-3 engines. Many of these engines were declared surplus in 1919 and found their way to builders of early very light aircraft. This information is detailed in Jim Warnock's excellent article "A Study of the Lawrance A-3 (C-2) Two-Cylinder Opposed Engine & Some of the Aircraft it Powered" (AAHS Sp 2006). The A-3 had a single-throw crankshaft with the pistons directly opposed, which resulted in the pistons both moving in the same direction at the same time causing excessive oscillatory lateral loads. Herschel Smith, in his book (S), describes the modification of the A-3 to a double-throw crankshaft by Orville Hickman as the Hickman C-2 Conversion. Warnock discusses the Hickman C-2 Conversion further with respect to an earlier conversion, which C.J. Brukner of Waco Aircraft said had been made to the A-3 used in the Waco Cootie I monoplane and Cootie II biplane of 1919-1920. Another very interesting article about Lawrance and all of his engines has been written and published (AAHS Su 2009) by Wesley R. Smith. It is entitled "The Curtiss TS-1 and the Engines of Charles Lanier Lawrance". The Lawrance HOAE are discussed, as well as the famous Lawrance radials mentioned in the next paragraph.

Lawrance continued engine development with his small three-cylinder L-series radials, leading to the Lawrance J-1 nine-cylinder radial in 1920. The Lawrance Aero Engine Co. was acquired in 1923 by the Wright Aeronautical Corp., of which Lawrance soon became President and served until 1930. During that period, Wright developed the Lawrance J-1 into the famous Wright J-4, J-5 and J-6 series engines known as the Whirlwinds. Lawrance later founded a new company, the Lawrance Engineering and Research Corp. of Linden, New Jersey. Lawrance E&R was involved in engine development in the 1930's and 1940's. Among other products, they developed auxiliary power units for aircraft, including some driven by horizontally-oppposed engines. Since these engines were not used as the principal means of aircraft propulsion, they are not described here. Please note that the spelling of Lawrance here is correct; sometimes his name is misspelled with an "e" instead of the second "a".

O-120 -- {4.25 / 4.25 / 120.6 } / {108.0 / 108.0 / 1976}

2cyl; Lawrance N-2; 30hp@1900rpm (of propeller); 1917; Wt = 79#; TC = none.
Dual-ignition engine, geared to N/A for the USN; development abandoned to concentrate on the three-cylinder L Series radial engines.
Ae39; BGE.
Applications: (US) Loening Kitten (underpowered with N-2).

O-150 -- {4.0 / 6.0 / 150.8 } / {101.6 / 152.4 / 2471}

2cyl; Lawrance A-3; 28hp@1400rpm; 1916-1918; Wt = 128#; TC = none.
Single-ignition engine built in quantity by Excelsior. An excellent photograph of a museum A-3 can be found here. The Hickman C-2 conversion is described on the Hickman Webpage given above.
AAHS Sp 2006, pp.6-16; Ae39; BGE; S; U&C.
Applications: (US) Breese Penguin trainers (short wingspan and incapable of flight); Driggs Dart; Mummert Cootie; Shinnecock lightplane; Swanson SS-3; Waco Cootie I monoplane and II biplane (see Warnock for discussion and other applications).


Updated 10/21/09