----- Original Message -----
Sent: Wednesday, February 16, 2005 2:58
PM
Subject: [FlyRotary] Re: Big Butterflies
vs Runners , was: Bruce Turrentine Intake
Bob,
Just to exercise my lack of understanding so I can get beat-up and
develop an understanding...
I was going to say, it looks like this manifold has 4.1sq inches of
throttle-plate to support 2.71 sq inches of sucking runners (one outside
runner and one inside runner) since only one rotor would draw at any given
time, but it looks more complicated than that.
2-rotors correct? Then whatever is being drawn
thru the middle intake port is dividing the load between both middle runners,
(while you're probably gonna set it up so that only one of the two middle
injectors fire at any time?) If, the size of the two
ports within each rotor chamber is the same, but you have two runners to the
middle port, wouldn't more air come in the middle port since it's
less restrictive? And therefore the middle feed is more lean than
the outer feed? Not that in the overall scheme of things it's any
kind of issue.
And I wonder why bother with providing two runners for
the middle port, why not just a single
runner? With a single middle runner could you
program a single middle injector to fire properly for both
ports? If not then retain two injectors for the single
middle runner?
But in any case, it may still
effectively work out to 2.71sq inches of porting behind the 4.1 sq
inches of throttle-plate.
Tom
Hi George,
The best I can measure them, the outside runners are 1
3/8 ID and the
inside runners are 1 1/4 ID. They blend smoothly into
the shape of the
ports on the engine side.
Bob White
On
Wed, 16 Feb 2005 09:00:14 +1000
"George Lendich" <
lendich@optusnet.com.au> wrote:
>
Bob
> What is the ID of the runners.
> George ( down
under)
>
Bob White <bob@bob-white.com>
wrote:
Hi
Jerry,
I noticed that the inlet to the TB has a slight taper and the
actual TB
throat is only about 58 mm. Interestingly, That's also about
4.1 sq.
in. I have Tracy's RD-1C, so have some hope of making at 7500
rpm.
It fits real nice in the cowling. I had Bruce bend it up so the TB
was
about 1 1/2 inches higher than if it was made horizontal. If I had
left
it horizontal, the TB would have come real close to interfering
with the
rubber isolator on the engine mount. I left the camera at home,
so
couldn't take any pictures.
Bob White
On Tue, 15 Feb
2005 13:04:43 -0500
Jerry Hey wrote:
>
Bob, that does seem large. For reference, the p port has two
>
butterflies for a TOTAL of 4.1 sq in. This was based on
>
calculations done by Rolf and should be good up to 8000 rpm. The
>
size is similar to what Power Sport is using and what Paul Yaw has
>
recommended. Jerry
> >
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