X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from mail24.syd.optusnet.com.au ([211.29.133.165] verified) by logan.com (CommuniGate Pro SMTP 5.0.4) with ESMTPS id 891870 for flyrotary@lancaironline.net; Wed, 21 Dec 2005 18:20:53 -0500 Received-SPF: none receiver=logan.com; client-ip=211.29.133.165; envelope-from=lendich@optusnet.com.au Received: from george (d220-236-206-11.dsl.nsw.optusnet.com.au [220.236.206.11]) by mail24.syd.optusnet.com.au (8.12.11/8.12.11) with SMTP id jBLNJw7B009293 for ; Thu, 22 Dec 2005 10:20:02 +1100 Message-ID: <00a601c60685$1246ba80$0bceecdc@george> From: "george lendich" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Props Date: Thu, 22 Dec 2005 09:20:01 +1000 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_00A3_01C606D8.E2D4FE70" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1106 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 This is a multi-part message in MIME format. ------=_NextPart_000_00A3_01C606D8.E2D4FE70 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Thanks Buly, So, Pitch" =3D MPH x12 x 5280 RPM x 60 I figure 12 (inches in a foot) and 5280 ( feet in a mile) and 60 ( = minute in an hour). So the top line is converted into inches per minute and the bottom line = RPM. So, Pitch " =3D inches per minute RPM Does that look right to you ? George ( down under) =20 Thanks George. my mistake was that i did not convert it to MPH. I was also given the formula for cruise speed: Pitch" x RPM x 60 =3D MPH 12 x 5280 Buly On Dec 21, 2005, at 4:39 PM, george lendich wrote: Buly, Looking at the formula given by members on this list, 2 out of 3 = were spot on with Hoverhawk and the third was close. Examples: 1. Prop Dia x 3.1416x RPM/ 720 - Correct! 2. Prop RPM x Dia x .00436 - Correct ( 3.14/ 720 =3D.00436) 3. 3.14 x 64 {given prop dia} ( 5500/2.17 {given RPM})=3D 508346/707 = - slightly incorrect ( as compared to the other 3 examples, which = include Hoverhawk) i.e 3.14/ 707 =3D .004809 whereas all the others are 3.14/ 720 =3D = .00436. Now that I have that sorted - can someone tell me how to calculate = pitch, easily!! George ( down under) Thanks Perry. This makes me feel much better. Looks like the = formulas given to me were not good. Buly On Dec 19, 2005, at 2:00 PM, Perry Casson wrote: I think your math is off a bit - Here's a online calculator = http:// www.hoverhawk.com/propspd.html I think 6900 puts a 72" prop close to mach 0.9 but I've never = ran mine above 6500 Perry Casson -- Homepage: http://www.flyrotary.com/ Archive and UnSub: = http://mail.lancaironline.net/lists/flyrotary/ Buly atlasyts@bellsouth.net -- Homepage: http://www.flyrotary.com/ Archive and UnSub: = http://mail.lancaironline.net/lists/flyrotary/ -- Homepage: http://www.flyrotary.com/ Archive and UnSub: http://mail.lancaironline.net/lists/flyrotary/ Bulent "Buly" Aliev = http://home.bellsouth.net/p/s/community.dll?ep=3D16&ext=3D1&groupid=3D164= 323&ck=3D ------=_NextPart_000_00A3_01C606D8.E2D4FE70 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

Thanks Buly,

So, Pitch" =3D MPH x12 x=20 5280

&nbs= p; =20 RPM x 60

I figure 12 (inches in a foot) and 5280 = ( feet in a=20 mile) and 60 ( minute in an hour).

So the top line is converted into = inches per minute=20 and the bottom line RPM.

So, Pitch " =3D inches per = minute

&nbs= p; =20 RPM

Does that look right to you = ?

George ( down under)

Thanks George. my mistake was that i did not convert it to = MPH.

I was also given the formula for cruise speed:

Pitch" x=20 RPM x 60 =3D MPH

12 x 5280

Buly

On Dec 21, 2005, at 4:39 PM, george lendich wrote:

Buly,

Looking at the formula given by members = on this=20 list, 2 out of 3 were spot

on with Hoverhawk and the third was = close.

Examples:

1. Prop Dia x 3.1416x RPM/ 720 - = Correct!

2. Prop RPM x Dia x .00436 - Correct ( = 3.14/ 720=20 =3D.00436)

3. 3.14 x 64 {given prop dia} ( 5500/2.17 = {given=20 RPM})=3D 508346/707 -

slightly incorrect ( as compared to the = other 3=20 examples, which include

Hoverhawk)

i.e 3.14/ 707 =3D .004809 whereas all the = others are=20 3.14/ 720 =3D .00436.

Now that I have that sorted - can someone = tell me=20 how to calculate pitch,

easily!!

George ( down under)

Thanks Perry. This makes me feel much = better.=20 Looks like the formulas

given to me were not good.

Buly

On Dec 19, 2005, at 2:00 PM, Perry = Casson=20 wrote:

I think your math is off a bit - = Here's a=20 online calculator http://

www.hoverhawk.com/propspd.html

I think 6900 puts a 72" prop close = to mach 0.9 but I've = never=20 ran

mine above 6500

Perry Casson

--

Homepage: http://www.flyrotary.com/

Archive and UnSub: http://mail.lanca= ironline.net/lists/flyrotary/

Buly

atlasyts@bellsouth.net

--

Homepage: =20 http://www.flyrotary.com/

Archive and UnSub: http://mail.lanca= ironline.net/lists/flyrotary/

--

Homepage: =20 http://www.flyrotary.com/

Archive and UnSub: http://mail.lanca= ironline.net/lists/flyrotary/

Bulent "Buly" Aliev

http://home.bellsouth.net/p/s/community.dl= l?ep=3D16&ext=3D1&groupid=3D164323&ck=3D

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