Cran,
Thanks for your very informed posts on this thread.
"I love diesel engines, my car has a diesel engine - but I wouldn't dream of putting one in a helicopter because they are not the right engine for the job."
Good point very well made - my car too. I can definately see the weight advantage of a turbine. My real point regarding diesel is that if you were to design an engine specifically for heli usage, you would run at least 2 stage (or even 3 stage) turbocharging to get the best power to weight (ideal is also 2-stroke). The actual engine would be very "solid", but would be very small for the air mass flow rate. This gives a happy compromise between cost, power, efficiency, and weight. Think of it as a piston high pressure stage gas turbine, which strikes me as the future of IC engine design anyway.
"Sadly they (auto diesels) wouldn't be able to produce this at peak output and thats how you would have to use them to get a helicopter off the ground."
If the diesel was optimised for constant RPM apps, then i don't fully agree. Cam would put max torque on max rpm, which would make for an undriveable car. Turbo is optimised for this RPM, at max power, which (for single stage) introduces lag similar to turbine. Boost then becomes BMEP controlled, maintaining efficiency. Again the result is a compromise specific to heli duty cycle.
Mart
Last edited by Graviman; 29th Jul 2005 at 08:58.