Date: Wed, 08 Jul 1998 23:07:19 -0400 From: "Marc J. Zeitlin" Subject: COZY: Re: NACA Scoop Design Will Chorley asks: >Marc, I cannot get to the mailing list at the moment and I wondered if >you would post this query for me please. (I am a member of the mailing >list!) (Will, if you can send email to me, you can send it to the list at: cozy_builders@canard.com >Does anyone have design information on NACA air Scoops? I would like to >know the co-ordinates for the curved intake, and the recommended >height/width ratio. Also, what's the best transition from the >rectangular "outlet" to a round section hose connection? > >Please reply to anneandwill@worldnet.att.net mjz again: (as well as the rest of us, of course :-) ) Marc J. Zeitlin                     marcz@burnside.ma.ultranet.com 3 Sweetbriar Way                    http://www.ultranet.com/~marcz/ Acton, MA  01720                    http://cozy.canard.com/ Date: Thu, 09 Jul 1998 12:16:04 -0800 From: hrogers@slac.stanford.edu (Howard Rogers) Subject: Re: COZY: Re: NACA Scoop Design Bill, this sounds great. I have wanted this sort of information for some time, though I have already built one of these ducts. I wanted to build one of a different size for the rear-seat passenger ventilation, and I could use this info to scale one perfectly. However, this wording: "X is the longitudinal distance along the duct, L is the total longitudinal length, Y is the width measured from the centerline of the duct, and W is the overall width of the duct. " Makes no sense to me. Even if I were to skecth out a duct and attempt to apply these numbers and formulae, I'm afraid my pea-brain would never be sure I was applying them correctly. Unfortunately, this is precicesly the type of thing that would benefit from one small picture, depicting exactly what is meant by the X, Y, L, and W values (as opposed to a thousand words). Could you clarify this a little further? Thanks. -Howard Rogers Date: Thu, 09 Jul 1998 08:13:06 -0400 From: bil kleb Subject: Re: COZY: Re: NACA Scoop Design Will Chorley wrote: > > Does anyone have design information on NACA air Scoops? > I would like to know the co-ordinates for the curved intake, > and the recommended height/width ratio. nasa does. i have gathered the primary reports and put them online through the naca report server: http://naca.larc.nasa.gov/ in addition, i wrote a brief summary of the findings: http://ab00.larc.nasa.gov/~kleb/naca/inlets.html a quote from this page: In general the width-to-depth ratio should be between 3 and 5 while the ramp angle should be between 5 and 7 degrees for optimal pressure recovery. The entrance lip at the rear of the duct should be a blunt airfoil leading edge shape; however, the edge formed by the duct and the surface elsewhere should remain crisp. The following table gives the coordinates for laying out the planform of a "curved divergence" NACA flush inlet where X is the longitudinal distance along the duct, L is the total longitudinal length, Y is the width measured from the centerline of the duct, and W is the overall width of the duct. X/L 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 Y/W .500 .497 .457 .382 .307 .233 .195 .157 .118 .080 .042 also, this info and how to turn it into a duct are available in the july '90 central states newsletter, page 2. > Also, what's the best transition from the rectangular "outlet" > to a round section hose connection? anything that is smooth and gentle; you don't want any abrupt angle changes to create separated flow regions. however, if you are going into the typical ribbed scat tubing, it doesn't really make any difference since that tubing has such high losses anyway... -- bil Date: Thu, 9 Jul 1998 22:04:15 -0400 From: "Edmond A. Richards" Subject: Re: COZY: Re: NACA Scoop Design Howard, All the dimensions for the NACA Scoop, along with layout drawings, are available in Tony Bingelis's book THE SPORTPLANE BUILDER. This book is one of a series of three by Tony available through the EAA. They are great reference books. Ed Richards Cozy #88