REFLECTOR: Roof NACA's

[Scott Derrick]

Rodney,

I'm somewhat surprised you feel you had better cooling with updraft.  I 
remember being told by a factory A&P that increased cooling capability 
was one of the reasons they switched to NACA's and down draft cooling.

One thing to consider is if your cht probes are on the bottom side of 
the cylinders(not spark plug washer type) with updraft  you will get a 
lower reading than with down draft because the cool updraft wind is 
blowing directly on the sensor side..  Makes it look like it was running 
cooler when in fact is was running hotter.

I will have a turbo that is mounted below the engine which mandates 
downdraft cooling.

Scott


Rodney Brim wrote:

> Additional Input on roof Naca's,
>  
> I've flown with the armpit scoops and the roof naca's, and found no 
> difference in speed.  So if you were planning on cutting into your 
> roof with the expectation that your cruise speed would  increase (as I 
> did), you might want to collect some more information from people 
> who've flown the same plane withboth cooling configurations.  In my 
> case  I wish I had never cut into the ceiling, as I wanted to afford 
> adults in the back all the ceiling they can get.   Btw I found the 
> best cooling when flying with armpits using an updraft.  In both 
> configurations I've been able to get into the mid 300's for cruise and 
> top out at 390 for max in climb by routing air to cylinders #1 & 2, 
> and paying attention to leaks.  I have a IO540 with 10 to 1 pistons, 
> so it creates  a lot of heat.
>  
> *Rodney Brim, *
>
> ------------------------------------------------------------------------
> *From:* reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] 
> *On Behalf Of *nmflyer1 at aol.com
> *Sent:* Monday, May 02, 2005 9:13 AM
> *To:* reflector at tvbf.org
> *Subject:* Re: REFLECTOR: Roof NACA's
>
> Scott,
>  
> This may dependant on your setup. I have the 173 elite, but am using 
> the larger NACA scoops for the XL.
> Scott S. helped me lay those out for my application. Do you have the 
> smaller fuselage, but are using the Lyc.540 now? You can either call 
> the factory for help, or I can measure them this evening when I get 
> home from work.
>  
>  
> Kurt 
>  
> -----Original Message-----
> From: Scott Derrick <scott at tnstaafl.net>
> To: Velocity Aircraft Owners and Builders list <reflector at tvbf.org>
> Sent: Mon, 2 May 2005 11:16:29 -0400 (EDT)
> Subject: RE: REFLECTOR: Roof NACA's
>
>Maybe I wasn't clear about this.
>
>I didn't ask how to build the NACA's, I have them, I asked how far apart
>they should be..
>
>Scott
>
>> FYI - I had similar questions about the roof NACA scoops a few weeks
>> back. I called Velocity about two weeks ago and they sent me the paper
>> templates & instructions on how to build them... for FREE!  Now that's
>> good support!
>>
>> Joel Carruth
>> Lockheed Martin
>> JSF - Pilot System Software
>> W: (817) 763-4337
>> Fax: (817) 777-8378
>> joel.l.carruth at lmco.com <mailto:joel.l.carruth%40lmco.com>
>>
>> -----Original Message-----
>> From: reflector-bounces at tvbf.org <mailto:reflector-bounces%40tvbf.org> [mailto:reflector-bounces at tvbf.org <mailto:reflector-bounces%40tvbf.org>] On
>> Behalf Of michalk
>> Sent: Monday, May 02, 2005 8:34 AM
>> To: Velocity Aircraft Owners and Builders list
>> Subject: Re: REFLECTOR: Roof NACA's
>>
>> This is a spreadsheet developed by a Reflectorite:
>> http://www.tvbf.org/docs/nacascoop1.1.xls
>>
>> I don't remember who wrote it.  Someone pipe up for this credit.
>>
>> It will plot the layout of your NACA so that you can cut it out
>> yourself.  Easy to make.
>>
>> KeithHallsten wrote:
>>> Scott,
>>>
>>> My kit came with the armpit scoops, but I made the top NACA scoops
>> using
>>> dimensions provided by Velocity.  I don't have my notes on that at
>> home, and
>>> won't be back to the hangar until Tuesday at the earliest, but the
>> factory
>>> guys should be able to give you the
>> fuselage-centerline-to-scoop-centerline
>>> measurement.  You will probably need to get the molded ducts (runners)
>> from
>>> the factory, anyway.
>>>
>>> Keith Hallsten
>>>
>>>
>>> ----- Original Message -----
>>> From: "Scott Derrick" <scott at tnstaafl.net <mailto:scott%40tnstaafl.net>>
>>> To: "Velocity Aircraft Owners and Builders list" <reflector at tvbf.org <mailto:reflector%40tvbf.org>>
>>> Sent: Sunday, May 01, 2005 7:42 PM
>>> Subject: REFLECTOR: Roof NACA's
>>>
>>>
>>>
>>>>Sorry folks I forgot to change the Subject line.
>>>>
>>>>Roof NACA's.
>>>>
>>>>I need to cut the holes in the roof to install the NACA's. My plane
>> was
>>>>a updraft, and the instructions say to cut out the pre-marked holes
>>>>which I don't have.
>>>>
>>>>Anybody know the spacing side to side, or center to center I should
>> use?
>>>>
>>>>Scott
>>>>
>>>>_______________________________________________
>>>>To change your email address, visit
>>>
>>> http://www.tvbf.org/mailman/listinfo/reflector
>>>
>>>>Visit the gallery!  www.tvbf.org/gallery <http://www.tvbf.org/gallery>
>>>>user:pw = tvbf:jamaicangoose
>>>>Check new archives: www.tvbf.org/pipermail <http://www.tvbf.org/pipermail>
>>>>Check old archives:
>> http://www.tvbf.org/archives/velocity/maillist.html
>>>>
>>>
>>>
>>>
>>> _______________________________________________
>>> To change your email address, visit
>> http://www.tvbf.org/mailman/listinfo/reflector
>>>
>>> Visit the gallery!  www.tvbf.org/gallery <http://www.tvbf.org/gallery>
>>> user:pw = tvbf:jamaicangoose
>>> Check new archives: www.tvbf.org/pipermail <http://www.tvbf.org/pipermail>
>>> Check old archives:
>> http://www.tvbf.org/archives/velocity/maillist.html
>>
>> _______________________________________________
>> To change your email address, visit
>> http://www.tvbf.org/mailman/listinfo/reflector
>>
>> Visit the gallery!  www.tvbf.org/gallery <http://www.tvbf.org/gallery>
>> user:pw = tvbf:jamaicangoose
>> Check new archives: www.tvbf.org/pipermail <http://www.tvbf.org/pipermail>
>> Check old archives: http://www.tvbf.org/archives/velocity/maillist.html
>> _______________________________________________
>> To change your email address, visit
>> http://www.tvbf.org/mailman/listinfo/reflector
>>
>> Visit the gallery!  www.tvbf.org/gallery <http://www.tvbf.org/gallery>
>> user:pw = tvbf:jamaicangoose
>> Check new archives: www.tvbf.org/pipermail <http://www.tvbf.org/pipermail>
>> Check old archives: http://www.tvbf.org/archives/velocity/maillist.html
>>
>
>_______________________________________________
>To change your email address, visit http://www.tvbf.org/mailman/listinfo/reflector
>
>Visit the gallery!  www.tvbf.org/gallery <http://www.tvbf.org/gallery>
>user:pw = tvbf:jamaicangoose
>Check new archives: www.tvbf.org/pipermail <http://www.tvbf.org/pipermail>
>Check old archives: http://www.tvbf.org/archives/velocity/maillist.html
>
>------------------------------------------------------------------------
>
>_______________________________________________
>To change your email address, visit http://www.tvbf.org/mailman/listinfo/reflector
>
>Visit the gallery!  www.tvbf.org/gallery
>user:pw = tvbf:jamaicangoose
>Check new archives: www.tvbf.org/pipermail
>Check old archives: http://www.tvbf.org/archives/velocity/maillist.html
>