"Michael D. Lilja" wrote:

Hi all,

As I am new to the rotary world I have a few basic questions about
rotaries.  I understand the basic operating priciples of a rotary
engine, but I would like to know more about their operating
characteristics.  What is the torque output of a rotary like?

Why do you want to know?  It don't got no stinking torque :-)
What do you need torque for?

HP = torque x RPM /5252

Therefore torque = (HP x 5252)/RPM

Lets say the engine HP is 200 at 6000 RPM.
The engine torque is  then 175 foot pounds at 6000 RPM.
The prop torque is 2.85 x 175 or 498.75 foot pounds.
Exercise for the reader. What is the prop HP?

The
recipricating engine still seems to be the most fuel efficient, what is
the reason for the rotaries relative inefficiency?

Sounds like a hit and run question.
No longer true. In fact Jan Car & Driver says the RX8 gets 19-20 mpg city
and 28-30 highway. EPA estimate. That is better than the vast majority
of 250 HP four passenger 2900 pound and above four place cars.

The rotary will run 100 degrees lean of peak unlike a piston engine.
We think this is because the the combustion chamber is rotating forcing
the fuel out towards the spark plugs providing a natural stratified charge
situation. Naturally there are no exhaust valves to fail so
you don't have to worry about that. Tracy Crook claims he can cruise
along side a lycoming and get the same fuel burn.

BTW C&D claims the RX8 does zero to 60 in 6.3 seconds and
the 1/4 mile in 14.9 at 95 MPH not bad for a car with no torque.
Apparently the test drivers at Car & Driver know how to drive
a rotary better than the test drivers at Motor Trend.
C&D also complains the turbo exhaust is too cool to trigger
the cat converter.

Is the horse power
output because of the RPM's attainable?

Yes of course. They are real Percheron draft horse's. See picture below.

 From a conveience standpoint,
(fuel available at the airport) what is the possibility of using 100LL?
 Thanks for the help and the newsletter.

Michael D. Lilja

100 LL is a bit hard on the plugs but a tank or two of no lead
auto gas seems to clean them up. We are working on a solution.
Probably multiple spark discharge ignition systems will do the
trick.


Merry Christmas.

Paul Lamar

6000 RPM's / 2.85 = 2105 prop RPM

498.75 X 2105 / 5252 = 199.9

Right back where you started with the 200 HP

COOL

 
The AirCraft Rotary Engine NewsLetter.  Powered by Linux.
ACRE NL web site. http://home.earthlink.net/~rotaryeng/            
Copyright 1998-2002 All world wide rights reserved.