X-Virus-Scanned: clean according to Sophos on Logan.com X-PolluStop-Diagnostic: (direct reply)\eX-PolluStop-Score: 0.00\eX-PolluStop: Scanned with Niversoft PolluStop 2.1 RC1, http://www.niversoft.com/pollustop Return-Path: Received: from [65.54.168.121] (HELO hotmail.com) by logan.com (CommuniGate Pro SMTP 4.3c4) with ESMTP id 867031 for flyrotary@lancaironline.net; Tue, 12 Apr 2005 20:48:57 -0400 Received-SPF: pass receiver=logan.com; client-ip=65.54.168.121; envelope-from=lors01@msn.com Received: from mail pickup service by hotmail.com with Microsoft SMTPSVC; Tue, 12 Apr 2005 17:48:12 -0700 Message-ID: Received: from 65.54.98.100 by BAY3-DAV17.phx.gbl with DAV; Wed, 13 Apr 2005 00:48:12 +0000 X-Originating-IP: [65.54.98.100] X-Originating-Email: [lors01@msn.com] X-Sender: lors01@msn.com From: "Tracy Crook" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Ram and Alt air Date: Wed, 13 Apr 2005 20:50:12 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0171_01C5406A.6324E300" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: MSN 9 X-MimeOLE: Produced By MSN MimeOLE V9.10.0011.1703 Seal-Send-Time: Wed, 13 Apr 2005 20:50:12 -0400 X-OriginalArrivalTime: 13 Apr 2005 00:48:12.0678 (UTC) FILETIME=[7870A260:01C53FC2] This is a multi-part message in MIME format. ------=_NextPart_000_0171_01C5406A.6324E300 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable FWIW, my current scoop is 2.125" in diameter. Tracy I have not actually studied the ideal ram scoop opening. I know that=20 Tracy is using a 3inch dia round scoop that would have about 7 inches = of area, just a little smaller than the scoop I proposed. I want to=20 keep the scoop as low as possible while retaining the performance. = The=20 snouts that stick up into the air are not the look I want. Does the=20 scoop get smaller with a higher top end? What would it be for 240 = mph?=20 Jerry On Tuesday, April 12, 2005, at 06:19 PM, Al Gietzen wrote: > > Here is pic of the plenum (at this point a piece of 1/4 inch ply. = The > ram air scoop will be 4 inches wide and two inches high. > > Jerry: > > Is the 2" x 4" the opening size? I think that is more than double = the=20 > area > that would give the amount of ram air needed for a 2-rotor at, say,=20 > 120 kts. > So it will be spilling air and likely cause some amount of unwanted=20 > drag. > Ideally, a ram induction scoop is close to the area needed for near = top > speed; and have radius on the entrance lip (about that of your index = > finger) > to minimize entrance loss when you are at low speed. > > FWIW, I have no idea it any of this matters for what you're doing. > > Al > > >>> Homepage: http://www.flyrotary.com/ >>> Archive: = http://lancaironline.net/lists/flyrotary/List.html > >> Homepage: http://www.flyrotary.com/ >> Archive: = http://lancaironline.net/lists/flyrotary/List.html ------=_NextPart_000_0171_01C5406A.6324E300 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

FWIW, my current scoop is 2.125" in diameter.

Tracy

I have not actually studied the ideal ram scoop = opening. I know=20 that
Tracy is using a 3inch dia round scoop that would have = about 7=20 inches
of area, just a little smaller than the scoop I = proposed. I=20 want to
keep the scoop as low as possible while retaining the=20 performance. The
snouts that stick up into the air are not = the look=20 I want. Does the
scoop get smaller with a higher top = end? What=20 would it be for 240 mph?
    Jerry

On = Tuesday,=20 April 12, 2005, at 06:19 PM, Al Gietzen wrote:

>
> = Here is pic=20 of the plenum (at this point a piece of 1/4 inch ply. = The
> ram=20 air scoop will be 4 inches wide and two inches = high.
>
>=20 Jerry:
>
> Is the 2" x 4" the opening size? I think = that is=20 more than double the
> area
> that would give the amount = of ram=20 air needed for a 2-rotor at, say,
> 120 kts.
> So it will = be=20 spilling air and likely cause some amount of unwanted
> = drag.
>=20 Ideally, a ram induction scoop is close to the area needed for near=20 top
> speed; and have radius on the entrance lip (about that of = your=20 index
> finger)
> to minimize entrance loss when you are = at low=20 speed.
>
> FWIW, I have no idea it any of this matters for = what=20 you're doing.
>
> Al
>
>
>>> = Homepage: http://www.flyrotary.com/
>&= gt;> =20 Archive:   http://lancai= ronline.net/lists/flyrotary/List.html
>

>>&nbs= p;=20 Homepage: http://www.flyrotary.com/
>&= gt; =20 Archive:   http://lancai= ronline.net/lists/flyrotary/List.html

------=_NextPart_000_0171_01C5406A.6324E300--