Turbo-Barillet compound multiple turbine engine concept......

[Caravellarella]

Dear Boys and Girls, here is an article in French about an unusual compound propulsion concept. The Turbo-Barillet uses the efflux from three small jet turbines (in this case the Armstrong-Siddeley Viper) to act jointly on a rear-mounted free turbine which powers a large diameter propellor through a normal reduction gearbox. The concept intends to show that compounding of small turbines can create a powerful propulsion system; the article shows that a triple-Viper unit can fit inside the same size engine cowling as a Pratt & Whitney R-2800 or R-4360 and would be shorter and lighter than a conventional turboprop engine (I think by implication a Turbo-Barillet could be a drop-in replacement for an existing piston engine). I do not know if this system was ever tested......

The article comes from the 6th July 1957 issue of Les Ailes......

Terry (Caravellarella)

 

[taildragger]

This sounds related to the American enthusiasm,about ten years earlier, for using large numbers of micro-turbojets in place of normally sized turbojets. I don't think either idea holds up under much analysis - probably why they didn't reach hardware. All other things being the same, three engines delivering the same SHP as one larger engine would tend to be heavier, less reliable (in MTBF), bigger, more costly and less efficient.