R.J. Isaacson worked in a railway company before designing his aviation engine in 1910, a 6-cylinder water-cooled 60 HP.

-It was installed in several Avro and Blackburn aircraft.

-In the illustration we see it on a B2 Flanders.

“Isaacson”

-It was a manufacturer of radial engines, fixed and rotary.

-Another well-known Isaacson engine is the 5-cylinder radial that gave 50 hp.

-Two rotaries were the 9 and 18-cylinder engines. The 9-cylinder gave 100 hp at 1,200 rpm.

-The 18-cylinder rotary delivered 200 hp at the same rpm.

“Isaacson 18-cylinder”

-Within the range of fixed radial engines we have the air-cooled 7-cylinder that gave 50 hp. The 14-cylinder is a double version of the above mentioned 7-cylinder radial. This engine gives 100 hp.

-There was also a 7-cylinder Isaacson that gave 65 hp at 1,100 rpm. This was a fixed radial engine.

From Appendix 6: Designed by the Isaacson Engine Co. in Leeds. Year 1911.

-They are stationary radials (rotary radials predominated at the time).

-The seven-cylinder engine gave 50 Hp at 800 rpm propeller speed, because they used frontal concentric gears.

“Isaacson, 50 HP”

-The 100 hp was a double version of two coupled 7-cylinder engines forming a 14-cylinder, with reduction gear as well.

“14-cylinder Isaacson, 100 hp”

-The radial rotary engine shown below is from 1913. It gave about 60-65 hp.

"The Isaacson rotary, 60-65 HP"

-Isaacson did the design and construction was done by Manning, Wardle and Co. at the Boyne Engine Works in Leeds.

From Appendix 7: We have a photograph of the Isaacson fixed radial engine from 1910, the 7-cylinder that gave 35/40 hp. It is taken from the side of the rocker controls.

“Isaacson engine with open accessory box”

-It is clearly seen that the cam-plate is on the ground, next to the front landing gear.

-The plate's speed reduction is made by three satellites driving the central control gear wheel.

-As we see in the following illustration, the cam plate is at the front.

-In addition, the propeller shaft is eccentric and elevated because it has a superimposed gearbox.

“Isaacson installed on a biplane” (PiP-fmr)

From Appendix 10: A 7-cylinder engine from this Leeds brand.

"Isaacson 7-cylinder fixed radial"

From Appendix 12: In an advertisement reproduced by Av.Ancestry we have more information about the characteristics of these engines.

“The mentioned ad”

-Although they look like rotary radial engines, here we are told that the cylinders are stationary, at least the 7-cylinder, 50 hp engines and the 14-cylinder ones that gave 100 hp.

-Propeller speed half engine speed or any other ratio.

-Seven explosions to one revolution of propeller without two-cycle principle inefficiency -obviously-.

-The propeller can rotate between 75 and 900 rpm. Although it surprises the author that the propeller has an intermediate position.