SNIP

 The conventional aircraft engines have no need to change, they have

 a captive audience that feels these are the only engines that will
 fly safely, and will continue to pay for antique parts.
 Heck, they still require a break-in, and we in the business know why.
 No need to go on, you know where I am coming from.
 Archie Frangoudis,
 Archie's Racing Service

The FAA is partially to blame for this. If any change at all is made in the
aircraft engine, and that includes material change, the engine must be
re certified. Naturally this discourages development.

On the other hand much of the work done on auto engines is to match
the durability and life to the low duty cycle of the automotive
environment and cut the cost. On board computer control of the
duty cycle is a modern glaring example.

If the automotive companies developed an aircraft
piston engine from scratch there would be no doubt in my mind that
it would look very much like an air cooled aircraft engine and be largely
made from the same materials. There have been few breakthroughs in strength
to weight ratio of metals and in the ratio of heat rejected to the number
of fins per inch in the past 50 years. 4130 and 4340 are still the preferred
materials for the ferrous parts.  I don't think liquid cooling is
worth the trouble and extra installation cost and weight.

The rotary on the other hand is a whole new ball game.

BTW here are some auto fuel prices per US gallon in suburban So CA
low test 1.85
high test 2.00
diesel 2.20

Where is the diesel advantage? Don't know what JP4 is going for.

Paul Lamar

Paul,

I agree TOTALLY on engines, esp water cooling.  Not necessary
unless you use 4 valve heads which are NOT necessary for slow
RPM engines, which ARE necessary for big, efficient props (in
part due to the fueslage screwing up the middle part of the prop
disk) without expensive and (actual service history of certified spur gear
systems, and a few certified opposed engine planetary gear systems)
troublesome gearboxes.   Gearboxes can be made to work, but
if you have a clean sheet of paper and a big barrel of money,
larger displacement and lower RPM is cheaper to build and lasts
better.   Since nobody has put a 4 liter rotary in a car, we have
to work with what we have and deal with the suboptimal (but very
workable) geared engine.   No problem.  My dream engine is
still a 3-4 liter two rotor Wankel with a built-in prop bearing
and aircooled, designed to run at about 2800-3000 RPM.   No
danger of getting it, sadly.  HMMM??

Is there any real possibility of designing one of these here and
getting a prototype built?  Jeff has done a lot of this and could
guide us, plus there is a lot of design and engineering talent
out there.   Pipe dream or mere insanity?

As to fuel, our reg unleaded is $1.47 and diesel is $1.33.  High test
is $1.67.    It took a big jump recently, was in the $1.25 range for a while.
You really need to move out of "Hotel California" - Oh, I forgot,
 "You can check any time you like, but you can never leave"   ;-)

California native, and did manage to leave.
(so I can throw a few stones at the Calcommies)

Bill

Long EZ builder & pilot
BSME, MSME

The AirCraft Rotary Engine NewsLetter.              Powered by Linux.

http://home.earthlink.net/~rotaryeng/            http://www.linux.org