Is there any information on the website showing the timing of the intake
 and exhaust port relative to eshaft rotation? I am specifically
 interested in the overlap and the e-shaft angle at which the apex seal
 clears the exhaust port.

 Inspired by your 555 system, I have designed a simple digital converter
 to convert MAP to pulse width for controlling the injectors.  We know
 that the volumetric efficiency of the p-port at 6000rpm is 120%.  I am
 wondering how much of that 120% is represented by intake air passing
 through the chamber and out the exhaust during overlap. If this occurs
 at all, it would improve efficiency to minimize the amount of fuel in
 the bypassed air, suggesting that the injectors should be opened after
 the exhaust is at least partially closed

 Victor Roberts


 I don't have the numbers for the timing but it is exactly the
 same as the Le Mans 4 rotor.

 http://www.rotaryeng.net/Mazda_R26B_US.pdf
 http://www.rotaryeng.net/Welded-steel-p-port.html

 The numbers can be derived from the scale dwg in this last link.

 The exhaust and intake P-ports in a rotary never really close.
 In that regard it is more like a turbo jet.
 What air does not go in one chamber goes in the next.
 In a tuned rotary engine however the max pressure in
 any given (One of 3) compression chamber depends on the RPM,
 pipe length and pipe diameter.

 http://www.rotaryeng.net/Mazda-p-port-press-wave-enhanced.jpg

 The best place to measure this pressure is the apex oil injector
 holes just above the p-port intake. Of course one is not using
 these holes for oil injection. One mixes the apex oil with the fuel.

 I am coming back to the 555 system and adding a single chip computer that
 has the sole job of adjusting the mixture using a USB port and
 storing the trim data in a spread sheet format. The program becomes
 extremely
 simple and easy to comprehend. Merely a look up table in the single
 chipper.

 Henry Nee came up with this great idea and people can email and share trim
 tables. Any number of trim tables can be stored in one's PC. It also makes
 editing the trim table simple as you do it in your PC using a spread sheet
 program. This should greatly speed the tuning of your engine and similar
 installations can use the same trim table. We can put them on the web site
 for rapid download. Parameters affecting the trim are type or drag of
 the airplane, diameter and pitch of the prop, intake pipe length and gear
 ratio used. Assuming all are using a p-port.

 Paul Lamar

 Victor,   I have seen the port timing numbers in the Kenji Yamaguchi (SP?)
papers.  I think there is a link on Paul's  site  and possibly on Craigs
Rotary List site also.

george grimes



     Reguarding the overlap period between the intake and exhaust ports of
a P-port rotary. It appears in the animated video that the face of the
rotor pretty much seals off against the 9 oclock position of the housing,
however this is not the case.  The combustion recess which is a trough in
the rotor face is unobstructed allowing a generous passage from intake to
exhaust. The pressure differential favors the exhaust resulting in exhaust
byproducts being carried along to the next intake cycle.  The use of side
exhaust ports on the RX-8 is somewhat more efficient in that the side face
of the rotor and apex seal block the path for more duration of the
rotation, however the combustion recess still carries combustion byproducts
to the next cycle.

       The tuned intake length is designed to have a reflected pressure
wave arrive at the port just  before it closes to increase volumetric
efficiency. When looking into a P-port it is obvious that much of the open
area at this time is into the following chamber. If this chamber is
evacuated more effectively by altering the side exhaust scavenging timing
then there is a  relatively lower pressure area which would allow more of
the possible intake charge to be diverted into the following chamber.
This is less of a problem with the side intake ports because the side of
the rotor blocks the path to the next chamber as the tuned pulse arrives.
Even with the stock unported side housings Mazda made 275 HP using a
technically complicated intake manifold.

       It might be possible to more effectively use  the tuned length
intake pulse on a P-port if the port shape favored the chamber on the
intake stroke. I would suggest a  "D" shaped port with the flat side of the
D towards the top of the rotor housing. The cross sectional area would need
to be similar to the round cross section before it. The housing machining
and port insert could both be CNC machined by lofting the two shapes in
Rhino with any interference  with the hosing machined from the housing.
The insert could be made by pressing a machined die into the round tube
insert to deform it to the D shape. The angle  of the intake runner
approaching the port might also be angled to point upward slightly more
inline with the volume being filled.

george grimes