<< Looks great, do you take out some of the rotor housing too?  I would
 > call that a full Bridgeport, would you agree?
 > [no signature] >>

The "bridge" port is just a narrow slot and does not include the rotor
housing beyond the sealing "O" ring.

The picture is of a "J" bridge port. The rotor housing is cut away until only
the outer wall of the sealing "O" ring groove is left to keep the coolant out
of the intake.

There is another version, where the rotor housing in the area of the port is
filled with
Devcon plastic aluminum (aluminum powder and Epoxy mixture) and the rotor
housing has one half of a periphery port cut into the face from each side. Since
there is no coolant in the rotor housing, there can be no leakage. The inner
wall of the port runner is cut into the epoxy mixture. Only the solid apex
seal, or the style with the small corner piece can be used. The style with the
large corner piece with the junction in the face of the seal could extend into
the port and cause a problem.

You can leave the side port open, or fill it with Devcon plastic steel and
cut the outer wall of the runner into the Devcon. It is not detectable from
outside the engine.

In this picture, the track of the leading end of the side seal is the left
scribe mark. The path of the trailing end of the side seal is the right scribe
mark.
A small street port would leave the material to support the leading end of
the side seal. So the port would be cut to just inside of that line. Maybe 1/16"
away. The trailing end of the seal is not harmed so long as the upper end of
the port is smooth where the seal drags back onto the flat part of the cast
iron.

In a big street port the side seal is not supported at all. So the port is
cut out until just some of the corner seal is supported to keep it from falling
into the port.

The closing point of the port pictured is 85 degrees ABDC. More typical for
the street port use would 50 to 60 degrees.

Paul Yaws web site has a great technical section and pictures of various port
styles.

http://www.yawpower.com/

Lynn E. Hanover

 
The AirCraft Rotary Engine NewsLetter.  Powered by Linux.
ACRE NL web site. http://home.earthlink.net/~rotaryeng/            
Copyright 1998-2003 All world wide rights reserved.