X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from mail34.syd.optusnet.com.au ([211.29.133.218] verified) by logan.com (CommuniGate Pro SMTP 5.1.12) with ESMTPS id 2346743 for flyrotary@lancaironline.net; Sun, 23 Sep 2007 02:37:47 -0400 Received-SPF: none receiver=logan.com; client-ip=211.29.133.218; envelope-from=lendich@optusnet.com.au Received: from george (d220-237-243-228.dsl.nsw.optusnet.com.au [220.237.243.228]) by mail34.syd.optusnet.com.au (8.13.1/8.13.1) with SMTP id l8N6axn9000947 for ; Sun, 23 Sep 2007 16:37:01 +1000 Message-ID: <006001c7fdac$2b258570$e4f3eddc@george> From: "George Lendich" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Area of a circle Date: Sun, 23 Sep 2007 16:37:08 +1000 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_005D_01C7FDFF.FB8FC6A0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.2180 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 X-Antivirus: avast! (VPS 0657-0, 12/12/2006), Outbound message X-Antivirus-Status: Clean This is a multi-part message in MIME format. ------=_NextPart_000_005D_01C7FDFF.FB8FC6A0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Thanks Ed, That's very good indeed! George ( down under) Ah, well, George, if you are using a slide throttle, then forget the = spreadsheet I sent you - that was assuming a rotating plate. In that = case it will depend on the shape of your slide, if a straight plate then = the area is fairly easy to find. I am assuming a throttle with a flat = straight edge sliding plate across the throttle area. Since there is no revolving throttle plate, the angle in the = spreadsheet is actually the angel between the center of the circle area = to the points where the sliding plate enters the throat. So when the plate is fully across the opening or closed - this angle = is zero, the angle is 180 deg when the plate is half way open and 360 = degree when it is fully open. That's about all I can along these lines. If the end of the sliding = plate is anything other than straight (no "V" notches, etc) then this is = not going to be accurate. Ed ----- Original Message -----=20 From: George Lendich=20 To: Rotary motors in aircraft=20 Sent: Saturday, September 22, 2007 8:06 PM Subject: [FlyRotary] Re: Area of a circle Thanks Ed, I'm looking at it - again! Mind you I'm wanting to use a slide throttle, so the butterfly = thickness and rod are not a factor in my non-venturi, straight through = 44 mm dia carb design. George ----- Original Message -----=20 From: Ed Anderson=20 To: Rotary motors in aircraft=20 Sent: Sunday, September 23, 2007 2:25 AM Subject: [FlyRotary] Re: Area of a circle I agree with Al, George. =20 However, if you wish to enjoy the thrill of calculating that area = (which is not a trivial task), here is a document that has all the = information (formulas) you need. http://med.ee.nd.edu/MED5/PAPERS/S5_3/S5_3.PDF Now if you are willing to assume that the throttle plate = thickness and its rod are not a factor (maybe not a bad real-world = assumption just to get the area of the opening - but different story = regarding its effect on air flow which is why Al's suggestion is a good = one), I have attached a spreadsheet with this simplification of the = math. Ed ----- Original Message -----=20 From: Al Gietzen=20 To: Rotary motors in aircraft=20 Sent: Saturday, September 22, 2007 12:06 PM Subject: [FlyRotary] Re: Area of a circle George; Determining the area of the opening of a circular butterfly with = position is certainly complex enough; but the flow is likely not = directly proportional because of the complexities of the flow = characteristics and pressure changes. I would think measuring it is = really the only way. Do you have access to a flow bench? Sorry; probably not very helpful, Al G -----Original Message----- From: Rotary motors in aircraft = [mailto:flyrotary@lancaironline.net] On Behalf Of George Lendich Sent: Friday, September 21, 2007 9:21 PM To: Rotary motors in aircraft Subject: [FlyRotary] Area of a circle Chaps,=20 I am trying to work out the area of carb inlet as it is opened = incrementally. This involves the overlapped portion of two circles, as well as, = a circle cut into slices ( straight cuts). This should give me an indication of the linier or otherwise, = volume of air as it sweeps through the carb. This then should indicate the shape of the grind of the needle = in maintaining continuity of the mixture ratio of fuel to air. Any helpers with this one!? George (down under) -------------------------------------------------------------------------= - -- Homepage: http://www.flyrotary.com/ Archive and UnSub: = http://mail.lancaironline.net:81/lists/flyrotary/List.html -------------------------------------------------------------------------= - No virus found in this incoming message. Checked by AVG Free Edition.=20 Version: 7.5.488 / Virus Database: 269.13.28/1021 - Release Date: = 21/09/2007 2:02 PM -------------------------------------------------------------------------= ----- -- Homepage: http://www.flyrotary.com/ Archive and UnSub: = http://mail.lancaironline.net:81/lists/flyrotary/List.html -------------------------------------------------------------------------= ----- No virus found in this incoming message. Checked by AVG Free Edition.=20 Version: 7.5.488 / Virus Database: 269.13.28/1023 - Release Date: = 22/09/2007 1:27 PM ------=_NextPart_000_005D_01C7FDFF.FB8FC6A0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Thanks Ed,
That's very good indeed!
George ( down under)

Ah, well, George,  if  you are using = a slide=20 throttle, then forget the spreadsheet I sent you - that was = assuming a=20 rotating plate.  In that case it will depend on the shape of your = slide,=20 if a straight plate then the area is fairly  easy to = find.  I=20 am assuming a throttle with a flat straight edge sliding plate across = the=20 throttle area.
 
Since there is no revolving throttle plate, = the angle in=20 the spreadsheet is actually the angel between the center of the circle = area to=20 the points where the sliding plate enters the throat.
 
So when the plate is fully across the opening = or=20  closed - this angle is zero, the angle is 180 deg when the plate = is half=20 way open and 360 degree when it is fully open.
 
That's about all I can along these = lines.  If the=20 end of the sliding plate is anything other than straight (no "V" = notches, etc)=20 then this is not going to be accurate.
 
Ed
 
 ----- Original Message ----- =
From:=20 George Lendich
To: Rotary motors in = aircraft=20
Sent: Saturday, September 22, = 2007 8:06=20 PM
Subject: [FlyRotary] Re: Area = of a=20 circle

Thanks Ed,
I'm looking at it = - again!
Mind you I'm wanting to use a slide = throttle,=20 so the butterfly thickness and rod are not a factor in my = non-venturi,=20 straight through 44 mm dia carb design.
George
----- Original Message ----- =
From:=20 Ed Anderson
To: Rotary motors in = aircraft=20
Sent: Sunday, September 23, = 2007 2:25=20 AM
Subject: [FlyRotary] Re: = Area of a=20 circle

I agree with Al, George.  =
 
However, if you wish to enjoy the thrill = of=20 calculating that area (which is not a trivial task), here is a = document=20 that has all the information (formulas) you need.
 
http://med.ee.nd.= edu/MED5/PAPERS/S5_3/S5_3.PDF
 
     Now if you are = willing to=20 assume that the throttle plate  thickness and its rod are not = a=20 factor (maybe not a bad real-world assumption just = to get=20 the area of the opening - but different story regarding its effect = on air=20 flow which is why Al's suggestion is a good one), I have attached = a=20 spreadsheet with this simplification of the math.
 
Ed
 
----- Original Message ----- =
From:=20 Al=20 Gietzen
To: Rotary motors in = aircraft=20
Sent: Saturday, September = 22, 2007=20 12:06 PM
Subject: [FlyRotary] Re: = Area of a=20 circle

George;

 

Determining=20 the area of the opening of a circular butterfly with position is = certainly complex enough; but the flow is likely not directly=20 proportional because of the complexities of the flow = characteristics and=20 pressure changes.  I would think measuring it is really the = only=20 way.  Do you have access to a flow bench?

 

Sorry;=20 probably not very helpful,

 

Al=20 G

 

-----Original=20 Message-----
From:=20 Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] = On Behalf Of George=20 Lendich
Sent: = Friday,=20 September 21, 2007 9:21 PM
To: Rotary motors in=20 aircraft
Subject:=20 [FlyRotary] Area of a circle

 

Chaps, 

I = am trying to=20 work out the area of carb inlet as it is opened=20 incrementally.

 

This involves=20 the overlapped portion of two circles, as well as, a circle cut = into=20 slices ( straight cuts).

 

This should=20 give me an indication of the linier or otherwise, volume of air = as it=20 sweeps through the carb.

 

This then=20 should indicate the shape of the grind of the needle in = maintaining=20 continuity of the mixture ratio of fuel to = air.

 

Any = helpers=20 with this one!?

George (down=20 under)

--
Homepage:  http://www.flyrotary.com/
Archive = and=20 UnSub:  =20 http://mail.lancaironline.net:81/lists/flyrotary/List.html

No virus found in this incoming message.
Checked by AVG = Free=20 Edition.
Version: 7.5.488 / Virus Database: 269.13.28/1021 - = Release=20 Date: 21/09/2007 2:02 PM

--
Homepage:  http://www.flyrotary.com/
Archive and=20 UnSub:  =20 http://mail.lancaironline.net:81/lists/flyrotary/List.html

No virus found in this incoming message.
Checked by AVG Free = Edition.
Version: 7.5.488 / Virus Database: 269.13.28/1023 - = Release Date:=20 22/09/2007 1:27 PM
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