One engine of this brand is a four-cylinder fan-shaped engine. There was also a three-cylinder, 25 HP fan-shaped (half-radial) version.

-It was installed on the Weiss monoplane with a tractor propeller. It would be replaced by a similar Anzani engine of the same power.

-A photograph of this air-cooled, four-cylinder fan-shaped engine has been located, with unit displacements of 90x120 mm.

“Warren-Simpson and Co. Engine”

-It produced 25 HP at 1,200 rpm and was presented at the 1910 Paris Motor Show.

From Appendix 9: Photograph of a fan-shaped engine of this brand, in the KJew Museum in France.

“Warren Simpson 4 cyl.” (AEHS)

-It's unusual for this type of engine to have 4 cylinders (even instead of odd). Two are noticeably advanced and the other two are further back, perhaps on a different crankshaft journal.