Received-SPF: pass
 receiver=logan.com; client-ip=66.133.182.164; envelope-from=canarder@frontiernet.net
Message-ID: <43566B75.9030104@frontiernet.net>
Date: Wed, 19 Oct 2005 10:51:17 -0500
From: Jim Sower <canarder@frontiernet.net>
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7) Gecko/20040514
MIME-Version: 1.0
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Re: NACA scoops
References: <list-773465@logan.com>
In-Reply-To: <list-773465@logan.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit

At RR a couple of weeks ago I looked at Terry's EZ with downdraft scoops 
cooling an O-320.  They had what looked like about half (or less) the 
inlet area of the NACA duct they replaced.

Ed Anderson wrote:

> Hi Thomas, afraid not exactly an old wives tale.   Here is an extract 
> from an  old NACA report that appears to take the position that 
> submerged (NACA?) ducts are not the best suited for radiators or 
> anything requiring much diffusion or pressure recovery. 
> Unfortunately,  I don't have the full report but the report number is 
> listed on the summary below if you wish to try and find it.   Any 
> extract can be misinterpreted taken out of the context of the total 
> report - but, it seems to take a position.  Also while NACA ducts may 
> not be the BEST possible for our type airspeeds and radiators - there 
> are always other factors to consider in trying to fit systems to 
> aircraft - space, location,weight, possible inlet locations, etc, 
> etc.  So while the NACA ducts may not be the best possible solution 
> for a theoretical installation, its other attributes may make it the 
> best of possible systems for the pushers.  Just an opinion of course.
>
> While looking through my files I also found a copy of the report you 
> cited which I though a comprehensive discussion of NACA inlets, 
> vortexes and boundary layer - appears to have some good material in it 
> - although I'll admit I have never done more than just skimmed it.
>
> http://naca.larc.nasa.gov/reports/1951/naca-tn-2323/
>
>
> Ed A
>
>
> ----- Original Message ----- From: "Ernest Christley" 
> <echristley@nc.rr.com>
> To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
> Sent: Wednesday, October 19, 2005 10:05 AM
> Subject: [FlyRotary] Re: NACA scoops
>
>
>> rijakits wrote:
>>
>>>
>>>     Remember the inventors of the NACA-duct did recommend to NOT use
>>>     it as a pressure-recovery intake (what we need for our our car
>>>     style radiators)
>>>
>> I've heard this repeated so many times, and yet I've never been able 
>> to find the report that said it.  I believe it is well on its way to 
>> becoming an old-wives-tale.  I've looked for a while in vain to find 
>> the exact quote this morning, but the closest I've been able to find 
>> was more along the lines of "we didn't test that, so we don't 
>> recommend it."
>>
>> "We don't recommend it, because we haven't tested it" is NOT the same 
>> as, "we don't recommend it because we found it doesn't work."
>>
>> All of the reports are online at naca.larc.nasa.gov.  That address 
>> starts you at the search page.  'submerged inlet' brings up the 
>> reports on NACA scoops, with the most germaine for our purposes being 
>> located at http://naca.larc.nasa.gov/reports/1951/naca-tn-2323/ .  
>> I'll keep looking for the quote I'm referring to above, but I would 
>> really appreciate a pointer to the report that says, "We found 
>> submerged inlets to be deficient for use with radiators."
>>
>> -- 
>>         ,|"|"|,                                    |
>> ----===<{{(oQo)}}>===----        Dyke Delta         |
>>        o|  d  |o          www.ernest.isa-geek.org  |
>>
>> -- 
>> Homepage:  http://www.flyrotary.com/
>> Archive and UnSub:   http://mail.lancaironline.net/lists/flyrotary/
>>
>