Lynn,

Just want you to know, was having a rough day out at the hangar, your signature turned it all around. 

So to better understand, the trailing plugs main purpose is to effect a smoother and more complete burn of the mixture. The plan to open the hole would be to try and gain 75% power on either leading or trailing plug... Based on trailing plug being clean up, would you not instead have to put a second hole next to both leading and trailing plug creating 4 plugs per rotor?

Mark

Mazda and others have tried thousands of combinations of intake and exhaust port shape as well as permutations of plug locations and quantities. And every other combination of shapes and locations imaginable. The Le mans engine had three plugs for better fuel efficiency as well as variable intake tuned length for best power. Not that the rotor is turning the burning mixture across the pinched waist of the housing, forcing the flame through the chamber cut into the rotor face. The fuel near the trailing apex seal is loosing heat to the rotor housing and droplets are forming as fuel condenses. This is where the trailing plug helps keep the fire going. The third plug had to be firing into the moving chamber face where the edges of the chamber were within a few thousandths of the housing walls. The Le mans engine was not turned up very tight. Under 8,000 RPM if I remember correctly. So the extra plug was enough of a help with the burn that even one or more extra pit stop for fuel were avoided and helped with a first time out win. The stunned governing body outlawed the rotary.

Some early production engines had three drilled holes for the exhaust port. The engines looked very much like the 2 cycle engines they mimic. It is a 4 cycle engine that tunes like a 2 cycle engine.  

 

The trailing plug has a very short time to get any kind of job done before the apex seal sweeps the burning mixture across the plug hole and renders the plug moot. So, the trailing plugs alone cannot provide enough power to do much but get you to the ground. You can try this by just turning off the leading ignition.

 

Better efficiency is no doubt available with the three plug layout, but the production costs and the ignition system complexity just rules it out. When the Rotary hit the market, fuel was quite a bit less expensive. 

 

Lynn E. Hanover

The taller idiot is me.

The shorter is Mike Bashem

Crew chief on the red car.

(National Champion)