wrote:
What would be the ideal configuration for an aircraft engine, given
contemporary technology?

1. Start at 0 degrees F with no fuss?
2. Water cooling for dependable cabin heat?
3. Automatic mixture control for altitude & power?
4. Automatic timing control?
5. Jet fuel (availability)?
6. Piston (for economy)?
7. Choice of RPM at cruise for same power?

I believe that delivering brand new airplanes with 1940s engines makes
no sense whatever.


While my response is more appropriate to the homebuilders forum, I
would have to say that an engine based upon the rotary engine concept
would meet many of those goals:

There are dozens flying now with engines that are either wholly or
loosely based on the Mazda 13B and 20B rotary engine cores. Mistral (in
Europe) is bringing out a rotary engine/PSRU combination that will
support a dual alternator and a constant speed prop. All of these
engines are oil and water cooled. I say oil cooled only because the oil
takes on a larger cooling burden in relation to a typical "auto" conversion.

With the exception of the Mistral, however, there are not any
firewall-forward installations for sale out there YET. Again, this is
where the reponse it more tuned to the amatuer built owners, rather than
the certified crowd. I realize that the vast majority of pilots want
to fly, not build.. and either lack the time, funds or inclination to
take on a custom engine project, and the required tweaking that will ensue.

That being said, a friend and I are building a Velocity, with a
powerplant consisting of a Mazda 13B "turbo" core engine. The driveshaft
will develop in excess of 200 hp with an attached gearbox dropping the
prop speed to around 25-2700 rpm. Hot oil, rather than water, will be
the source of cabin heat (per plans from Velocity). The PSRU we are
using will be able to operate on autogas or 100LL, as well as any
forseable gasoline product that will be used in the near future. Inital
operations would use unleaded fuel during the fine tuning of the
electronic ignition/advance, since an oxygen sensor is used for those
trials.

Maintenance in the amatuer built arena tends to be the bastion of
owners, but since this engine is heavily based on the Mazda designed
engine, spare parts can be obtained from any mazda dealer in the US, as
well as from specialty shops in the US as well as abroad. I am forseeing
a "maintenance pack" that will consist of the required tools to
completely remove and tear down the motor in an unimproved locale - a
few metric sockets, a torque wrench, breaker bar, some picks, etc. These
engines in the race setting have literally been torn down and rebuilt on
a 5 gallon bucket at the track. This isn't a lot of weight, and in fact
may constitute some of the ballast our airframe may require.

Sorry for the ramble.. and.. by the way.. the wankle concept of rotary
engines is 40's technology too.. but no valves, no camshafts, 3 moving
parts (not counting seals/springs). Water cooled means you can have
tighter tolerances, better efficiency..

Dave