Summing up Shytorque, powerful but you'd never know they were there. Any specific preference of engine? I'm guessing RR 250 C30P (206 powerplant).
Flingwing207, i use the VW turbodiesel as an example of the type of engine which would fit my (pretty undemanding) requirements. I am really more curious how much a factor the engine is to the pilot, or whether it is more a concern to the helicopter concept design team.
----
General facts about automotive diesels:
Truck turbodiesels operate at 90% for much of their lives and are designed to last >15'000 hours. Power-to-weight is however totally impractical for aero use. The latest VW turbodiesels offer ~100BHP/litre, so would easilly achieve 1800 hours (equivalent to ~100'000 miles), if 90% power was rated at say 50BHP/litre.
When laying out a piston engine the first consideration is piston speed. Once skirt loads are established, this very directly determines life of the engine. My belief is that emerging combustion technologies will reduce skirt loading while allowing higher rpms. There are also designs of piston (crosshead) and crank mechanism (epicycloidal) which may greatly reduce piston friction for improved BSP/Hr durability, allowing significantly higher turbo boost pressures. The aim for aero usage (cost less of a factor) would be >2kW/kg, which combined with improved fuel burn (kg/NM), puts it in competition with RR250 (4kW/kg).
Mart
Last edited by Graviman; 19th Nov 2006 at 07:35.
Reason: Typos