Hi,
The whole weight issue is a bit of a blind statement - The performance of Diesels continues to improve - and weight will only be reduced in the comming years.
The Diesel Engine would be ideal for a Helicopter - because of what a diesel is good at - That is running at low revs all day!
Even the best Diesles will top out at 5000rpm -
Isn't the question therefore wheather or not we can design a suitable gearbox? Can we really have a diesel flat out at 4 - 5000rpm geared up enough without losing power for even an R22?
Just a thought
Rich