Good morning,
i'm Christian Carestia, student of mechanical engineering from
Italy.  I'm writing a thesis on the Wankel engine.  I made a CAD
3d draw with solid edge of a Wankel SW92 for airplane models and
now i want to develop a software that can give the basic
geometric parameters of the main parts of the
Wankel (epitrochoidal chamber, rotor, rotor journal, pinion gear)
and that can extract kinematics values(i used the formulas of
the book RE by Kenichi Yamamoto of 1981) and also get theoretical
torque and power curves.  The problem is that i can't find a way
to get the mechanical efficiency or the pressure inside the
engine.  Do you have any suggestions on how I can find the
torque curve based on the kinematic parameters i have?  is there
a way to approximate the mechanical efficiency?I ask you because
your site is the most detailed on the subject.If you want I'll
send you a copy of the thesis and also the excel spreadsheet i
developed for the calculation.Thanks in advance for your reply.

Best regards,
Christian Carestia

I believe we answered this.
I guess you were not on the newsletter
at the time.

Paul Lamar



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-------- Original Message --------
Subject: INFO WANKEL ENGINE
Date: Wed, 30 Jun 2010 09:48:54 -0700
From: Rotary Engine <rotaryeng@earthlink.net>
To: AAA Put this in the To box <rotaryeng@earthlink.net>

Hi,
I'm Christian Carestia, i study mechanical engineering in Italy
and i'm doing a thesis on Wankel engines.  I did a 3d model of
the Wankel SW92, angine for model airplane of year '62, and i
was trying to create a software to help in the construction of
the wnkel engine.  I already can extract geometry and dynamics
parameters, but i can't find a good way to extract the hp/torque
curve.  I have these data:



2.1-DESCRIPTION OF THE MOTOR

The SW92 has the following specs:

Swept volume.............. 9.2 CC
Compression ...............7.4:1
Max Power output...........1.5 HP
Power at 12000rpm..........1HP
Fuel...................... Methyl alcohol
Lubricant................  10-20% Caster oil
Glow Plugs................ Start 1.5V
Weight.................... 900-930g
Eccentricity.............. 3.5mm
Major Radius.............. 28mm
Rotor thickness............18mm
Apex seal replacement interval..30 H


with these data, i can find the mean effective pressure of the
engine at 12000 rpm, and i can also extract the pressure at max
power output(i suggested it is 20000 rpm)

Now I can 't find nowhere how much should be the mean indicated
pressure, and i can't find a way to extract the mechanical
efficiency.  Foe the efficiency i have some ideas(i found
formulas for the rotor gears and the bearings) but i have no
idea on how to find a good variation of indicated pressure.

Can you give me some suggestions? i'd really appreciate it
because i have only 20 days to finish the thesis!

I can put your name on my thesis and i'll send you a copy if you
want.



Thanks in advance for your reply!

All the best!

Christian

How did you calculated the Swept volume? The RX8 engine is not
1.3 L. It is 2.6 L. The compression ratio is 10:1 and not 7.4:1
Side port VE is 100%
P-port VE is 120%

Here is some actual data.


Paul Lamar

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