Mailing List flyrotary@lancaironline.net Message #35274
From: H & J Johnson <hjjohnson@sasktel.net>
Subject: Re: [FlyRotary] Re: New Cowl Contest
Date: Tue, 30 Jan 2007 17:13:05 -0600
To: Rotary motors in aircraft <flyrotary@lancaironline.net>

Thanks Ed, the website is in the works. I'm not a webdesigner so I've out-sourced it and that can take time to get it 'right'. Because of the actual machine dimensions, machining Titanium is out of the question, anything under a mild steel is possible however. I'll know more after testing and commisioning of the complete unit. [These types of things are a bit un-known as a machine of this size is built to order, its not something you just 'go down and buy'] Getting it set up and installed has been an experiance.

Jarrett [I can't wait to get'er running, thats for sure!]

 

----- Original Message -----

From: Ed Anderson <eanderson@carolina.rr.com>

Date: Tuesday, January 30, 2007 4:55 pm

Subject: [FlyRotary] Re: New Cowl Contest

> Good Grief, Jarrett, that is a monstrous piece of machinery (even
> a smaller version).  Looks like you could carve your own SR-71 out
> of a single piece of titanium.  Impressive.  Looking forward to
> your website.
>
> Ed
>  ----- Original Message -----
>  From: H & J Johnson
>  To: Rotary motors in aircraft
>  Sent: Tuesday, January 30, 2007 5:09 PM
>  Subject: [FlyRotary] Re: New Cowl Contest
>
>
>
>  George, its a Gantry Mill, the parts sit almost right on the
> floor and the gantry runs on two long side rails which are bolted
> into the floor. Attached is a picture showing a similar type of
> machine. This particular unit is from Scaled in So-cal. Mine is
> smaller than this unit, but then I didn't have the budget that
> they do :-)
>
>  I'll have pictures/vid's up on my website, which should be in
> about a month.
>
>  Jarrett
>
>
>
>  ----- Original Message -----
>
>
>  From: George Lendich <lendich@optusnet.com.au>
>
>  Date: Tuesday, January 30, 2007 3:58 pm
>
>  Subject: [FlyRotary] Re: New Cowl Contest
>
>
>  >
>  >   Jarrett,
>  >  What sort of CNC is that ?
>  >  George ( down under)
>  >
>  >
>  >
>  >
>  >
>  >
>  >  Dave,
>  >
>  >  I'd vote for the smiley, I would still wonder if having the
>  > opening out off the bottom face of the cowl wouldn't be
> better.
>  > Mind you, two other things come into play. There probably
> isn't to
>  > much [more] turbulent air or thicker boundry layer that close
>  > behind the prop at that location. No more than the turbulance
>  > farther out. Secondly, the rotational vector up close to the
> cowl
>  > very well could be less than farther out.[ to exagerate the
> issue,
>  > imagine the rotational vector out near the prop tip's.]
>  >
>  >  I've designed a few cowls  over the last couple years.
> Attached
>  > are a couple pictures to illustrate. Since you plan to use a
> lower
>  > and upper ducting, I've attached drawings/pic's showing how
> I've
>  > done both designs. It would be a simple matter to combine the
> two,
>  > to arrive at your desired design.
>  >
>  >  Also I've not said much in the past, but my CNC mill has been
>  > installed and is just awaiting final wire-up and commisioning.
> I
>  > plan to start offering its use to the Rotary crowd in
> producing
>  > components like cowls, proper diffusion ducting, spinners
> [which
>  > properly fair into the cowls] etc. Theres many other
> components
>  > I'd like to get into building but plan to start out with these
> few
>  > and expand from there. The mill is currently capable of
> milling
>  > parts up to 8 x 18 x 3 [feet] and will be upgraded in the
> spring
>  > to have a 4ft [instead of 3] Z axis. Later, we plan to expand
> its
>  > abilities to 5 axis, however this is more in the neighbourhood
> of
>  > a year or so.
>  >
>  >  I'll have a website up in the next month or so. However the
>  > meantime, if I can be of help, please let me know.
>  >
>  >
>  >
>  >  Jarrett Johnson
>  >
>  >
>  >
>  >
>  >
>  >
>  >
>  >
>  >
>  >  ----- Original Message -----
>  >
>  >
>  >  From: David Leonard <wdleonard@gmail.com>
>  >
>  >  Date: Tuesday, January 30, 2007 2:22 pm
>  >
>  >  Subject: [FlyRotary] Re: New Cowl Contest
>  >
>  >
>  >  > Todd, if it aint broke dont fix it!!!!
>  >  >
>  >  > You are right about the boundry layer.  But you can make up
>  > for
>  >  > that with a
>  >  > little extra size or maybe moving closer to the prop (eg P-
>  > 40).
>  >  >
>  >  > Also, Doug dempsy has been telling me how Chuck Dunlap had
> a
>  > real
>  >  > problemwith a duct that was away from the boundry layer,
> but
>  > fixed
>  >  > his issue when
>  >  > he make it bigger and more like the smile.
>  >  >
>  >  > The smile votes seem to have it so far...
>  >  >
>  >  > Dave Leonard
>  >  >
>  >  >
>  >  > On 1/30/07, Todd Bartrim <bartrim@gmail.com> wrote:
>  >  > >
>  >  > > I was thinking that the "oh cowl" would be better at
>  > excluding the
>  >  > > boundary layer, which would be better for cooling. This
> is
>  > just
>  >  > based on
>  >  > > comments I've read on the list during previous ducting
>  >  > discussions. Based on
>  >  > > this info, I felt my oil cooler duct was less than
> optimal
>  > (even
>  >  > though> temps are good), so I figured I could reduce the
> size
>  > of
>  >  > my inlet if I
>  >  > > eliminated the boundary air layer. As your "smile" duct
> is
>  >  > similar (see
>  >  > > attached pic) I figured this would be applicable. I hope
> I'm
>  >  > wrong and you
>  >  > > prove it before I change my cowl.
>  >  > >
>  >  > > Todd    (building Electric Bob's Audio Isolator Amplifier
>  > today)
>  >  > >
>  >  > > On 1/30/07, Ernest Christley <echristley@nc.rr.com >
> wrote:
>  >  > > >
>  >  > > > David Leonard wrote:
>  >  > > >
>  >  > > > > I call them the "Oh Cowl" and the "Smiley Cowl..."his
>  >  > > >
>  >  > > > Go with the smile, but put a raised ledge on the cowl
> side
>  >  > just behind
>  >  > > > the spinner to accelerate the air and thin the boundary
>  > layer.
>  >  > Reduces
>  >  > > > the ingestion of turbulent air.  Check the CAFE
>  > Foundation's drag
>  >  > > > reduction report.  They have a picture of what it looks
>  > like
>  >  > on a
>  >  > > > production aircraft.  I have a link to it at home, but
> not
>  > here.
>  >  > > >
>  >  > > > --
>  >  > > >          ,|"|"|,              Ernest Christley       |
>  >  > > > ----===<{{(oQo)}}>===----    Dyke Delta Builder      |
>  >  > > >         o|  d  |o        http://ernest.isa-geek.org  |
>  >  > > >
>  >  > > > --
>  >  > > > 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/
>  >  > >
>  >  > >
>  >  > >
>  >  > >
>  >  >
>  >  >
>  >  > --
>  >  > David Leonard
>  >  >
>  >  > Turbo Rotary RV-6 N4VY
>  >  > My websites at:
>  >  > http://members.aol.com/_ht_a/rotaryroster/index.html
>  >  > http://members.aol.com/_ht_a/vp4skydoc/index.html
>  >  > http://leonardiniraq.blogspot.com
>  >  >
>  >
>  >
>  > ---------------------------------------------------------------
> ----
>  > -----------
>  >
>  >
>  >  --
>  >  Homepage:  http://www.flyrotary.com/
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> http://mail.lancaironline.net/lists/flyrotary/
>  >
>
>
> -------------------------------------------------------------------
> -----------
>
>
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