X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from cdptpa-omtalb.mail.rr.com ([75.180.132.120] verified) by logan.com (CommuniGate Pro SMTP 5.1.12) with ESMTP id 2347051 for flyrotary@lancaironline.net; Sun, 23 Sep 2007 08:46:42 -0400 Received-SPF: pass receiver=logan.com; client-ip=75.180.132.120; envelope-from=eanderson@carolina.rr.com Received: from edward2 ([24.74.103.61]) by cdptpa-omta03.mail.rr.com with SMTP id <20070923124603.VRIU3971.cdptpa-omta03.mail.rr.com@edward2> for ; Sun, 23 Sep 2007 12:46:03 +0000 Message-ID: <000f01c7fddf$d5175940$2402a8c0@edward2> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Area of a circle Date: Sun, 23 Sep 2007 08:46:59 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_000C_01C7FDBE.4DD3ACC0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.3138 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3138 This is a multi-part message in MIME format. ------=_NextPart_000_000C_01C7FDBE.4DD3ACC0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Yes, I've always enjoyed using math to try to get a model for what the = real world is doing. But, as I always say our Math models are a = dumbed-down representation of the real world, so don't be surprised if = you find differences between the two (:>). Have fun, George. Ed ----- Original Message -----=20 From: George Lendich=20 To: Rotary motors in aircraft=20 Sent: Sunday, September 23, 2007 2:47 AM Subject: [FlyRotary] Re: Area of a circle Ed, I intend adding a notch to the square slide for a couple of reasons, = but I don't know if either reason is valid, but I can just treat it as = an add-on. The graph seems to validate what I had done manually today - it's all = very interesting isn't it!? 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_000C_01C7FDBE.4DD3ACC0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
 Yes, I've always enjoyed using math to try = to get a=20 model for what the real world is doing.  But, as I always say our = Math=20 models  are  a dumbed-down representation of the = real world,=20 so don't be surprised if you find differences between the two=20 (:>).
 
Have fun, George.
 
Ed
----- Original Message -----
From:=20 George=20 Lendich
Sent: Sunday, September 23, = 2007 2:47=20 AM
Subject: [FlyRotary] Re: Area = of a=20 circle

Ed,
I intend adding a notch to the square = slide for a=20 couple of reasons, but I don't know if either reason is valid, but I = can=20 just treat it as an add-on.
The graph seems to validate what I = had done=20 manually today - it's all very interesting isn't it!?
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=20 in the spreadsheet is actually the angel between the center of the = circle=20 area to 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=20 half 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,=20 etc) 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=20 8:06 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=20 2:25 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=20 air 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=20 aircraft
Sent: Saturday, = September 22,=20 2007 12:06 PM
Subject: [FlyRotary] = Re: Area of=20 a circle

George;

 

Determining=20 the area of the opening of a circular butterfly with position = is=20 certainly complex enough; but the flow is likely not directly=20 proportional because of the complexities of the flow = characteristics=20 and pressure changes.  I would think measuring it is = really the=20 only 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=20 to 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=20 maintaining continuity of the mixture ratio of fuel to=20 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=20 Edition.
Version: 7.5.488 / Virus Database: 269.13.28/1023 - = Release=20 Date: 22/09/2007 1:27 PM
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