Perry Mick wrote:

Has anyone used the Racing Beat PP housings? I don't feel comfortable
reworking a housing.

PP [rotor housing] for non-turbo
http://www.racingbeat.com/resultset.asp?PartNumber=11021
$837.00

PP [rotor housing] for turbo
http://www.racingbeat.com/resultset.asp?PartNumber=11024
$837.00

What about building up a complete aluminum engine using these parts?
Sure they are expensive, but you are still looking at probably less
than
$8K for an engine, low by airplane standards. They have a part for

the

20B as well.

Aluminum Intermediate housing
http://www.racingbeat.com/resultset.asp?PartNumber=11061

$1,550.00

Aluminum Rear Side housing
http://www.racingbeat.com/resultset.asp?PartNumber=11071
$1,200.00

Aluminum Front Side housing
http://www.racingbeat.com/resultset.asp?PartNumber=11051
$1,200.00

Aluminum Rear Side housing 20B
http://www.racingbeat.com/resultset.asp?PartNumber=11072
$1,200.00

--
Perry Mick
http://www.ductedfan.com

The front and 20B intermediate alloy housings are news to me. Perhaps
Francois can talk
Jim Mederer at Racing Beat  into certifying those RB end housings.
That would save a lot of money
for Francois not making his own end housings. Then all you need do
Francois is make
and certify your own rotor housings, rotors and e-shaft.

This several year old RB engine only uses two aluminum end housings.

Paul Lamar

Perry,  According to Mederer, his p ports are too large for a 6000 rpm
engine.   One can have either too big or too small ports depending on
RPM.  This is not an extremely sensitive issue requiring great
precision.     I can tell  you that my 1.5" dia.  ports which are fine
for 6000 to 7000rpm, will run out of capacity at 8000 rpm   according
to calculations I just received from Rolf Pfeiffer.    However, they
are easily modified with a die grinder if higher RPM is planned.  I am
going to make my ports a little wider (1.75") horizontally.   Enlarging
horizontally  does not effect timing.   I am doing so to slow the inlet
charge down.   According to Rolf's analysis,  is important to limit the
velocity of  the intake mixture to less than 0.5 mach.  Above that,
the engine will start to choke.

  Large ports, on the other hand,  have exhaust overlap issues that I am
guessing become less significant as the rpm increases but are
undesirable if they can be avoided.     Rolf has sent me an insightful
analysis of  PPort sizing and timing that I will post if he gives me
permission.   All of the "expert" sounding comments you hear from me on
this subject are learned from him.   Rolf,  may I  post your data and
comments?

As far as boring the housing is concerned, I don't think  you have to
worry about it.  Just take the housing to a good machinist.    I  have
done it once on a practice 12A housing, and it was not a problem.  If
you check my insert drawings  you will note that  the ports are located
  in inches from the housing center line.  Makes it easy for the
machinist.  I will be doing a practice 13B housing next week.  I will
report back on how it goes.

   Jerry  (not a machinist or engineer sadly)

Boberrorusa wrote:

"Jerry, the no SPIN doctor" seems to speak highly  of the Technician.
Boberrorusa

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