The engines of Kemp Machine Works, of Muncie, Indiana, were known by the nickname "Gray Eagle".

-In 1911 they made the Gray Eagle D-4 model engine, with four vertical in-line cylinders, an output power of 35/40 hp and 255.36 cu. in. of displacement. It was air cooled.

“Kemp D-4”

-The same goes for the two-cylinder G-2 that we show below. It was manufactured between 1913 and 1916 giving 16 hp at 1,200 rpm.

-It had single ignition using a battery and a high voltage coil. There is one (photo) at the NASM.

“Kemp G-2”

-The Kemp engines were manufactured between 1911 and 1916.

-The E-6 and H-6, were made in 1912.

“H-6”

-They built about 100 units of the H-6. The one shown above is No. 85, taken from an auction brochure.

-Another view of the opposite side but of another H-6 engine. This water-cooled engine has 6 inline cylinders and gives 50-55 hp at 1,150 rpm with 383 cu. in. of displacement. It is taken from the carburetor side.

“Kemp I-4 variant, installed” (AEHS)

-The I-4 was a four-cylinder air-cooled engine and like the D-4, it gave 35 hp at 1,150 rpm.

“I-4”

-The Kemp J-8 was an engine with eight cylinders in V that delivered 80 hp at 1,150 rpm. It had Mea magnetos and Zenith or Schebler carburetors.

“J-8”

-The J-8 is from 1913 and displaced 539 cu. in.

-They converted the four-cylinder inline Henderson motorcycle engine with 27 hp.

From Appendix 6: The air-cooled 80 hp V8 engine is now available in an illustration from 1915.

-The view from the side of the fan that forces the cooling air is the same as the main text, but now we bring a new one from the opposite side.

“Dos vistas del Kemp de 90 CV, Con y sin carenas”
“Two views of the 90 hp Kemp engine, with and without grips”

From Appendix 9: Engine exposed at a museum. Kemp I-4 (possibly)

“Kemp from 1911, 25 HP”

“Kemp at the NASM”

From Appendix 10: Of a subsequent "collection". Built by the Kemp Machine Works of Muncie in Indiana.

-In the main text, we mention two models of initial Kemp engines, the two-cylinder (G-2), the four-cylinders (D-4, I-4 and J-4), the six-cylinders (H-6 and E-6) and the 8-cylinder Vee-engine (J-8). The generic name of all of them was that of "Gray Eagle".

-They were mainly constructed between 1912 and 1914. They are very similar to Rubel without knowing any relationship between them.

-The main difference is found by the author in the form of oil sumps, magneto holders and in some measurements, but the overall architecture is almost identical.

“Twin-cylinder boxer model G-2”

“Kemp D-4”

-The author finds in the oil pan or crankcase the same rectangular shape, but only in the central part, not like the Rubel brand that is integral.

“The six-cylinder H-6, with centered oil pan”

-As a curiosity an illustration of the D-6 below and without oil pan.

“The D-6 with integral crankcase or sump”

"The Kemp V8, model J-8"

-In 1914 the V-8, model J-8 appears that also has the fan at the end of the engine shaft or propeller.

“Crankshaft of 6 journals and seven bearings on bed”

-Another interesting curiosity: the installation of a Kemp G-2 in an assembly for an air-boat.

“Propeller assembly driven by a Kemp G-2 engine”