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Chris,
Can't answer all your questions, as I don't know
how the different port shapes affect HP. I can however give you my
appreciation of Hp and that is; a standard side port
which provide approximately 160 to 180hp if really lucky. The different
side ports vary up to 200 hp +, however the PP is the ( our) answer in my
opinion, as it gives a direct shot into the combustion chamber. If you use the
minimum size PP ( 44mm) for our RPM ( up to 7,200/ 7,500) you will achieve the
200hp -230hp+. It all varies with how efficient the inlet and exhaust is
done.
I know it doesn't answer all your questions, but
it's enough for me.
Now that Bill Jepson is working on the new PP
things should be more reliable.
Reliability is subjective, if you get more power
your putting more stress and wear on the engine - naturally. Apart from that
there aren't any reliability issues with different ports.- that's
IMHO.
George ( down under)
I know this must have been discussed, but perhaps more in passing or in
some of Tracy's literature (now kinda dated, especially
with some of the strides he continues to make), but what is the conventional
wisdom as to rotary horsepower? I know when I first started looking into
it, oh many years ago, it seemed the impression I got was that you could
pretty easily achieve 200 hp, however, that is now a bit lower. Some of
the tricks to get the higher HP was mild and medium porting, bridge, "J" and
"P" porting. Then there was the option of turbo...the one, in
combination with a medium street port, I chose.
What say Ye?
When started today, mine was turning about 6200 rpm at 35 MP (with a 3 lb
spring in the wastegate ).....it surged forward against the
chocks and breaks. IVO prop full fine. Nice feel of
power even if it likes to heat up fast in 90 degree weather like this.
Also, I think this was discussed before too, when I
go WOT my engine develops up to about 6250 rpm,
but then drops a couple/few hundred rpm to usually just under
6000....sometimes just above. Thoughts? Ed, (perhaps Al)it seems
you may have chimed in before. Regrettably , when I search
the archives I tend to get frustrated due to thread drift.
I heard a lot about porting when I was initially investigating all this
and I chose to use a medium street port. I
let Mazdatrix do the work. That being said, I have
read all but nothing on others porting their engines (other than a LOT from PL
on P ports). Since standard porting does not reportedly effect
reliability, only, potentially low low idle (I can idle as
low as about 1300 rpm when warm smoothly) why is it not discussed and/or
utilized more?
Just curious guys/gals. Discuss <g>
All the best,
Chris Barber
From: Rotary motors in aircraft [flyrotary@lancaironline.net] on
behalf of Ed Anderson [eanderson@carolina.rr.com]
Sent: Wednesday,
May 26, 2010 5:15 PM
To: Rotary motors in
aircraft
Subject: [FlyRotary] Re: Emailing: 3 view w-10 003, first
flight
Always loved the
lines of a Tailwind – in fact, I have the plans and license to build a W-10
sitting on my book shelf. Unfortunately, I doubt I’ll ever get around to
it.
Ok with thermostat in
the system holding it at 190F – we really won’t know how much reserve capacity
you have in your cooling system until the power goes up.
I agree with George,
200HP out of an N/A 13B is really pushing it. I think 180HP is a more
realistic expectation – but, hey you never know. It amazing how power
goes up when things come together.
Enjoy and fly safe.
From: Rotary
motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of John
Sent: Wednesday, May 26, 2010 2:36
PM
To: Rotary motors in
aircraft
Subject: [FlyRotary]
Emailing: 3 view w-10 003, first flight
My most humble thank you to
flyrotary and all you fine folks that have helped bring my project
to flight. Ed and many others whom I won't try to name here because I
would miss many. The plane is a Wittman Tailwind W-10, empty wt. is 981
and it is a tri-gear, Wt. is within 6 #'s of similar trikes w/ 0-320
engines. I have the thermostat in the engine because most of the year it
is not very hot, if we get 50 days with the temperature over 70, we have had a
hot summer, not a lot of beach bunny activity. 7-1 I'll be 74 and have
realized my dream, now it's all gravy. Again, thanks guys!!
JohnD
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