Strange motor concept in which a liquid transmitting medium is used to drive the propeller turbine.

“Holmes project”

-The liquid had to be sent at high pressures and the one that had to be used was based on "freon", dangerous, corrosive, etc.

-It was not practicable, although there was thought of other liquids such as alcohol, benzol, anilines, xylol, toluol, ether, etc.

-It was known as a "thermodynamic" plant.

-The whole unit turned out to be very heavy and it remained pure theory.

-In 1939/40, a Holmes barrel-type engine with reference 3410-452.8 was filed at the USNA.

From Appendix 6: In the main text there is the schematic drawing of this designer's steam aircraft.

Now we have available a drawing of the generator boiler, and better yet, with the capacity to drive two tractors and another auxiliary for services.

“Steam generator and receivers”

"Another Holmes design to go on the wing"