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Hi Dave,
yes, there is no doubt the side port (old 13B or new
Renses) can easily make 170 HP at 6000 rpm. However, there are those
who have been disappointed in the power there installation produced. This
is seldom ever the fault of the engine - but induction and exhaust systems must
be given some thought and study in order to get the best. Exhaust back
pressure, for example, has long been reported to very detrimental to
rotary power.
I think many people simply have too large an
induction area. I know when I first started back in 1992 contemplating my
rotary installation, the only people I had to go to were the rotary
racers. They told me what was the "cats meow" for an induction
system. So I ended up with a dual throat Weber throttle body with 4
injectors. Each throat had a 2" dia opening. I estimate I was
probably producing around 130-140 HP on my first flights (1998) and while the RV
flew Ok (186 TAS was max speed) the take off roll was long and climb was around
700-800 fpm.
In 2000, I went from the short length 2"dia dual openings
to much smaller diameter (1 1/2 " dia secondary and 1 1/4" primary) tubes and
longer induction tube lengths. Power and performance increased
dramatically. Rate of climb increased by 300 fpm. Then, when I
went to the high compression rotors in 2001 and a 91 turbo block, rate of climb
was up to 1200 fpm. The finally? step was to go with the 2.85:1 gear box
and much larger prop which moved rate of climb at gross weight to 1600 fpm and
top speed 200 MPH TAS.
So what turns out to be the "cats meow" for racers buzzing
9000 + rpm is not necessarily idea for engine turning 5500-6500
rpm.
So my viewpoint is anybody who wants to experiment with
"P" ports should be encouraged to do so - we all learn from experimentation -
but, its not necessary if your objective is producing 160-170 HP.
Ed
----- Original Message -----
Sent: Thursday, November 09, 2006 7:28
AM
Subject: [FlyRotary] Re: P Porting
template?
Hi Hans, Doug , Ed, anyone else,
looking at the Mazda dyno
graphs,
All RX8 engines are side port, the 4 port makes 200+ at 7000 right
out of the box, so you can easily get 170-180 at 6000 rpm.
BR, Dave
McC
On 9, Nov , at 6:10 PM, Hans Conser wrote:
Well, telling you upfront that I am not flying a 13B; I disagree
with Ed, I don't think you will see that sort of power with a side port 13B
unless you are over 7500 RPM. At leaast this is what I think based on some
dyno runs with various side port engines I have built. P-Port is the way to
go.
Hans
On Nov 8, 2006, at 9:03 PM, Ed Anderson
wrote:
Hi Doug,
If
you want to develop between 160 and 170 HP from a 13B, I for one would not
consider a P port. The reason, is that the stock 13B will easily
give you that kind of power with less effort and cost. If you wanted
HP on the order of 200 + then a P port might be one approach to
consider.
Now
if you simply want to experiment with a P port, then got to it. But,
it is simply not needed for the power levels you are looking for.
The
only person I am aware of who may have the information you want is Jerry
Hey - he use to be on the list, but I have not seeing anything from him
recently. This is the last e mail address I have for
Jerry Hey
E-mail Address(es):
jerryhey@earthlink.net
you
might send him a message.
Best
Regards
Ed
----- Original
Message -----
From:
DLOMHEIM@aol.com
To:
Rotary
motors in aircraft
Sent:
Wednesday, November 08, 2006 10:45
PM
Subject:
[FlyRotary] P Porting
template?
I
have a friend in Denver who is willing to set up his milling
machine to mill out some P-Ports on a couple of my old rotor
housings over Thanksgiving break. My question is if any of you
know where I can get a copy of a template for use with 1.5"
diameter intake pipes. I would think there would be something in
the public domain by now (but I could be wrong). The
potential benefits of a P-Port make it pretty attractive to at least
experiment with at some point and I will be happy to develop between 160
and 170 hp in my 9A so I think that should be doable...
Doug
RV-9A,
13B
installation
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