X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from mxo4.broadbandsupport.net ([209.55.3.84] verified) by logan.com (CommuniGate Pro SMTP 5.2.11) with ESMTP id 3417367 for flyrotary@lancaironline.net; Thu, 08 Jan 2009 17:46:28 -0500 Received-SPF: pass receiver=logan.com; client-ip=209.55.3.84; envelope-from=candtmallory@cebridge.net Return-Path: Received: from [72.47.141.206] ([72.47.141.206:56916] helo=home) by mxo4.broadbandsupport.net (ecelerity 2.1.1.23 r(18304)) with ESMTP id BB/D1-22349-D1286694 for ; Thu, 08 Jan 2009 17:45:50 -0500 From: "The Mallorys" To: "'Rotary motors in aircraft'" References: In-Reply-To: Subject: RE: [FlyRotary] Re: Spinner size Date: Thu, 8 Jan 2009 16:45:12 -0600 Message-ID: <004e01c971e2$c4495e60$4cdc1b20$@net> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_004F_01C971B0.79AEEE60" X-Mailer: Microsoft Office Outlook 12.0 Thread-Index: AclxQEvHFN418+08QB2+OgP8iZJxOAAojyvQ Content-Language: en-us This is a multipart message in MIME format. ------=_NextPart_000_004F_01C971B0.79AEEE60 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Bob, =20 I don=E2=80=99t know why James made the rotary cowl different. I think = he made it for Powersport, so maybe they had the requirement. What kind = of prop are you going to use? If a Catto 76/80, maybe we can work a = swap of spinners, and I can get the bigger UHS one. =20 Chris =20 From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On = Behalf Of Bob Perkinson Sent: Wednesday, January 07, 2009 9:21 PM To: Rotary motors in aircraft Subject: [FlyRotary] Re: Spinner size =20 Chris, You must be the person Ann at Van's was talking about. Ann mentioned = to me that someone had a Sam James cowl and the spinner was to small, I = wast ordering my finish kit less the cowl at the time. I have a Sam = James cowl that I got from Bernie Kerr. I told her that I would get = back with her about the spinner. I immediately went to my storage = building and measured the face of the cowl, it was 13". The only = difference that I see is that you have the cowl that has the one large = cooling opening at the bottom. The cowl I have has two cooling inlets = like the vans cowl. I wonder why the .75" Difference in the cowl face? Bob Perkinson =20 -------------- Original message from Charlie England = : --------------=20 > Al Gietzen wrote:=20 > >=20 > > I have the James rotary cowl--front =E2=80=9Cface=E2=80=9D has a = 13.75=E2=80=9D diameter. I=20 > > also have the Vans 13=E2=80=9D spinner that is already cut to fit my = CATTO=20 > > prop. This leaves about a 3/8 lip of cowl showing all the way around = > > the spinner. Take a look at the picture.=20 > >=20 > > I know any amount of lip will cause drag, but is this enough to=20 > > warrant a new spinner? UHS makes a 14=E2=80=9D one that would = probably do the=20 > > trick.=20 > >=20 > > Chris=20 > >=20 > > My opinion is that is more a matter of appearance than function. The = > > air flow at that point is very turbulent, and any resultant drag = would=20 > > be less than measurable.=20 > >=20 > > BTW; on the post about the fuel pressure sensor I thought you were = the=20 > > other Chris with the Velocity.=20 > >=20 > > Al G=20 > >=20 >=20 > I can't even spell aerodynamicist (& neither can my spell checker), = but=20 > everything I've read says that it's better to have the cowl face = bigger=20 > than the spinner bigger. My impression is that the air will speed up=20 > slightly but not be greatly disturbed as it continues around the cowl, = > but if the spinner is bigger it will cause really bad turbulence as = the=20 > air tries to turn the corner at the edge of the spinner to fill that = gap.=20 >=20 > Will James assured me that the stock Van's spinner fits his cowl, so = I'm=20 > going with his assurance.=20 >=20 > FWIW,=20 >=20 > Charlie=20 >=20 > --=20 > Homepage: http://www.flyrotary.com/=20 > Archive and UnSub: = http://mail.lancaironline.net:81/lists/flyrotary/List.html=20 ------=_NextPart_000_004F_01C971B0.79AEEE60 Content-Type: text/html; charset="utf-8" Content-Transfer-Encoding: quoted-printable

Bob,

 

I don=E2=80=99t know why James made the rotary cowl = different.=C2=A0 I think he made it for Powersport, so maybe they had the requirement.=C2=A0 What = kind of prop are you going to use?=C2=A0 If a Catto 76/80, maybe we can work a = swap of spinners, and I can get the bigger UHS one.

 

Chris

 

From:= Rotary = motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Bob = Perkinson
Sent: Wednesday, January 07, 2009 9:21 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Spinner size

 

Chris,
You must be the person Ann at Van's was talking about.   Ann mentioned to me that someone had a Sam James cowl and the spinner was to small,  I wast ordering my finish kit less the cowl at the = time.  I have a Sam James cowl that I got from Bernie Kerr.    I = told her that I would get back with her about the spinner.  I immediately = went to my storage building and measured the face of the cowl,  it was 13".  The only difference that I see is that you have the cowl = that has the one large cooling opening at the bottom.  The cowl I have = has two cooling inlets like the vans cowl.  I wonder why the .75" = Difference in the cowl face?

Bob Perkinson

 

-------------- Original message from Charlie = England <ceengland@bellsouth.net>: --------------


> Al Gietzen wrote:
> >
> > I have the James rotary cowl--front =E2=80=9Cface=E2=80=9D has = a 13.75=E2=80=9D diameter. I
> > also have the Vans 13=E2=80=9D spinner that is already cut to = fit my CATTO
> > prop. This leaves about a 3/8 lip of cowl showing all the way = around
> > the spinner. Take a look at the picture.
> >
> > I know any amount of lip will cause drag, but is this enough = to
> > warrant a new spinner? UHS makes a 14=E2=80=9D one that would = probably do the
> > trick.
> >
> > Chris
> >
> > My opinion is that is more a matter of appearance than = function. The
> > air flow at that point is very turbulent, and any resultant = drag would
> > be less than measurable.
> >
> > BTW; on the post about the fuel pressure sensor I thought you = were the
> > other Chris with the Velocity.
> >
> > Al G
> >
>
> I can't even spell aerodynamicist (& neither can my spell = checker), but
> everything I've read says that it's better to have the cowl face = bigger
> than the spinner bigger. My impression is that the air will speed = up
> slightly but not be greatly disturbed as it continues around the = cowl,
> but if the spinner is bigger it will cause really bad turbulence as = the
> air tries to turn the corner at the edge of the spinner to fill = that gap.
>
> Will James assured me that the stock Van's spinner fits his cowl, = so I'm
> going with his assurance.
>
> FWIW,
>
> Charlie
>
> --
> Homepage: http://www.flyrotary.com/
> Archive and UnSub: http://mail.lancaironline.net:81/lists/flyrotary/List.html =

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