Jules,
The slide rule comes out (hope im not holding it upside down...) The
butterfly torque is controlled by the following parameters:
1.seal friction (virtually non-exsitent)
2. bearing friction (directly related to unbalanced pressure force across
the butterfly disc)
3. non-symmetrical pressure loading around the butterfly axis *
4. disc /fluid dynamic torque
Hmmph
The unbalanced pressure force across the disc (now referred to as UPF) is
directly related to the delta pressure across the disc and the projected
area of the disc in the flow path. To address the "jump" off idle, The
forces generated by this "property"are much greater than any aerodynamic
forces potentially causing a "torque reversal" (+ we got a big A** spring
on the throttle shaft holding it down ). The UPF is massive (relatively)
due to the very low pressure under the plates caused by the air flowing
around the perimeter...I think the "Jump" is due to the complete unshrouding
of the plates on the leading edge. "Unshrouded" butterfly valves flow about
20% of total up to approx 50 deg rotation, and the factory "shrouded" valve
a lot less. Unshroud, and whoa... big flow for little rotation...
For Max flow.... Yep, we separate at the trailing edge of the shaft at 60+
deg (and lower too probably) But, We got Big A** plates to compensate.
Maybe that ol mystery shaft can get us to 780cfm by reducing the seperation
"choking" @ WOT. Then again, Im not sure my truck would like that much
right now. Maybe after the alpha filtering/data rejection of the MAP signal
to avoid those big overlap bumpstick pos pulses..... Time to call the
Flometrics man!
www.flometrics.com
BKB
-----Original Message-----
From: Jules Glogovcsan [mailto:jghunter@nol.com]
Sent: Thursday, November 19, 1998 8:41 AM
To: dakota-truck@buffnet.net
Subject: DML: Re: Aero Shafts...? was: TB status (Frank)
----------
>
> Bridges, Bruce wrote:
> >
> > Bob,
please email Frank. Hes turning the cranks..
> > and a little centerless grinding for the shafts. Not many secrets
there!
ohh....
Not many [too] secrets there! ... but certainly some....
frank... didn't i see at the site showing the ss tbi shafts a [VERY]
rounded half-shaft with a flat side to bolt the tbi throttle plate to?
wouldn't this create a laminar flow disruption for a max efficiency effort?
maybe off-idle flow problems...?... wot/part throttle cfms exceed many
aircraft lift off air speed air flow rates for a particular wing
desing/airfoil shape... airfoil shape is important here... wouldn't you
agree? so wouldn't airfoil pressures be compromized... uneven laminar
flow...? uneven bore pressures... limiting max efficiency efforts...thru
the port... a split column of air fighting against itself ?
why do you make new shafts... anyway!?! how are the bellcranks
reattached...?
you are a pilot... [:)] with your own birds... you fly PIC... have you ever
seen a wing with a flat top foil shape...? have you ever seen a wing with
two humps in it on the top side of the wing's airfoil...?
jam'n
post is not a flame... but only to stimulate thinking... are we REALLY...
on the right path here?!?... why are we remaking a perfectly good shaft...?
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