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Thanks Bill,
I will look at that as well!
Is that 4H squared or 4x ( h squared)
George (down under)
George,
You
need to solve for the area of the circular segment opened by the slide
throttle. The formula is
A=1/2[rl-c(r-h)]
A=area, r-radius, l=lenght on the perimeter, c=chord,
h=chord height
Since lenght on the perimeter can be tough to determine,
there is an alternate formula. There is a slight error (less than .1%)
A=4h^2/3 times sq root of c^2/4h^2+0.392
area equals four times h
squared divided by three times the square root of c squared divided by 4 times
h squared plus 0.392
(pg 75 mahninery's handbook 21st ed.)
That will
give you the cordal area of 1/2 of the opening obviously. You can figure the
cross-sectional area of the needle to remove. You can do openings at various
throttle openings and then graph of extrapolate the points between. Good
luck!
Bill Jepson
-----Original Message-----
From: George
Lendich <lendich@optusnet.com.au>
To: Rotary motors in aircraft
<flyrotary@lancaironline.net>
Sent: Sat, 22 Sep 2007 4:55
pm
Subject: [FlyRotary] Re: Area of a circle
Al,
I am using a slide throttle and initially thought
I would just do trial and error, but figured if I could just get a handle on
variables it would help with the initial taper grind on the needle. I guess I
could just go linier and see how that goes. I could use an O2 sensor to check
fuel/air ratio, then regrind a new needle.
George (down under)
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