.. The problem with conventional 4 stroke
aircraft engines has been weight, and the need to put them into a bigger
heavier airframe. I'm very encouraged by the developement of engines like
the HKS and Warner, as they appear to offer a nice blend of light
weight/power/reliability.



Ian


Published performance specs for the HKS:
56HP @5800RPM 4.2gph/.45bsfc.
This will require a volumetric efficiency of 110%. Not bad for an
engine running at 75% throttle. In fact, not very likely.

Published performance specs for the Verner:
63HP(75%) @3750RPM. 2.7gph/.25bsfc Much more reasonable 55% volumetric
efficiency with 75% power, but absolutely astonishing fuel efficiency.
In fact, not very likely fuel efficiency.

Both engines achieve their light weight by running at high rpm with
small displacement, and by using Nikasil aluminum cylinders. Which is
to say, they are race car engines.

Would you rather have a C-85 with 2000 hours TT or a Verner with 600
hours TT? Or a 2 stroke with cast iron cylinders?

I would appreciate it if someone would check my numbers and see if they
come up with similar results.

--
John Kimmel

remove x

"He's dead, Jim."