REFLECTOR: Overhead NACA's (was "Rudder Pedal stops")

Rene Dugas dugasd at bellsouth.net
Wed Apr 15 21:59:04 CDT 2009 

I did it as Larry did and made mine one inch wider with about 2.25"  
depression as it goes under the lip and into the rectangle cut in the  
firewall.   About 600 hrs flying and no cooling problems even in  
Louisiana summers. I too have the firewall aft cooler but mounted a 1"  
tall scoop in the duct aft of the NACA to place the same high pressure  
air into the cooler and the same low pressure I have in the cowl. No  
problems with taxi even for 45 min at Oshkosh.

Rene' Dugas
Sent from my iPhone 3G

On Apr 15, 2009, at 11:53 AM, "Richard D. Wallace, Jr." <rdwallace57 at gmail.com 
 > wrote:

> How far did you push the skin down?
>
> On Wed, Apr 15, 2009 at 8:45 AM, Lawrence J. Epstein, MD
> <ljepstein at hotmail.com> wrote:
>> You guys are "fastbuild" compared to me (13 years and counting).  
>> Mine is so
>> old that NACA's hadn't been invented yet (not really) ( we had to  
>> walk
>> uphill to school, both ways, in the snow, no shoes………)
>>
>>
>>
>> Anyway…………..The factory sent me the templates and I cut them  
>> out myself (no
>> opinion as to whether these are real NACA's or not). I cut  
>> everything except
>> the forward most part and just pushed the skin down to the desired  
>> depth. I
>> used 1/4" foam for the sides and covered them with bid. About 6-10  
>> hours
>> work.
>>
>>
>>
>> Larry Epstein
>>
>>
>>
>> From: reflector-bounces at tvbf.org [mailto:reflector- 
>> bounces at tvbf.org] On
>> Behalf Of jerry at jlbent.com
>> Sent: Wednesday, April 15, 2009 8:22 AM
>> To: Velocity Aircraft Owners and Builders list
>> Subject: Re: REFLECTOR: Rudder Pedal stops
>>
>>
>>
>> Just to add to the challenge on the NACA ducts, you might want to  
>> consider
>> the efficency of the factory design.  While they look like NACA  
>> ducts, they
>> are not.  Andy Millin has spent a lot of time researching the topic  
>> and has
>> a spreadsheet that does the calculations to produce the needed  
>> profile.  One
>> very big difference (and maybe the most important) is that the  
>> factory
>> solution does not have an airfoil on top of the opening.  Of course  
>> the
>> amount of work needed to create a real NACA vs buying the factory  
>> pre-fab is
>> not trivial.
>>
>> I too am a SLOOOW builder and have a kit that did not come with the
>> pre-fab'd NACA's.  Mine did not even have the NACAs drawn on the  
>> fuselage.
>> I had read Andy's information and decided to build my own.  Just  
>> let me say
>> that one can get really obsessive about the details.  I would say  
>> that Brett
>> and I have at least 50 hours of work on them.  Some is my learning  
>> curve.
>> Some is just ! the details.  We did the extra work to make the  
>> floor of the
>> ramp flat, which is not what you get if you just cut the outline,  
>> build the
>> side walls and call it done.
>>
>> As of yet, I can not say that the true NACA will be better.  Hangar  
>> 18
>> suggest NACA's and believes they are better.  I do know that those  
>> in the
>> Vari community think the Velo factory NACA are just wrong and will  
>> produce
>> more drag and be less efficient than a proper NACA.  For the amount  
>> of work
>> involved in both hands on construction and the amount of head  
>> scratching
>> needed to build true NACA's, it is very hard not to go with the  
>> factory
>> pre-fabs.
>>
>> If you decide to go with the true NACA, let me know and we can talk
>> details.  Maybe I can save you some time.
>>
>> Jerry Brainard
>>
>>
>> -------Original Message-------
>> From: Richard D. Wallace, Jr.
>> Subject: Re: REFLECTOR: Rudder Pedal stops
>> Sent: Apr 14 '09 7:08pm
>>
>> Noel:
>>
>> I'm on the slow path also.  I got my kit for Christmas 2000.  My
>> fuselage has the NACA scoops outlined on the top also.  What do you
>> make the sides out of - BID?  Also what is the dimension on the
>> opening in the firewall?
>>
>> Rick
>>
>> On Tue, Apr 14, 2009 at 6:28 PM,  <gattenby at tulsaconnect.com> wrote:
>>> Rick.
>>>
>>> I'm taking the slow path to building an SUV as well (8 years and  
>>> counting)
>>> I've not done the pedal things as I'm missing some parts. (got my  
>>> kit 2nd
>>> hand)
>>>
>>> The NACA scoops can be bui! lt without the prefab inserts.
>>> My kit predated the inserts.  They weren't that big a deal.
>>> The kit had the lines drawn on the top, and I just cut them.
>>>
>>> If you need templates just let me know and I'll trace mine on paper.
>>>
>>> Noel
>>>
>>> On Tue, 14 Apr 2009 17:30:24 -0400
>>>  "Richard D. Wallace, Jr." <rdwallace57 at gmail.com> wrote:
>>>> Guys:
>>>>
>>>> I don't provide comments (lack of experience and I have
>>>> a single door,
>>>> fixed gear, dual yoke control SUV) but I do and have
>>>> read all e-mails
>>>> back and forth.  I seem to be just behind in
>>>> construction than some
>>>> and the need to ask questions is always unnecessary
>>>> because the
>>>> ! subject has already been discussed.  However, I have
>>>> come up with two
>>>> (2) questions:  1) do you need stops for the break
>>>> pedals so they are
>>>> not putting pressure on the master brake cylinder heads
>>>> when the
>>>> springs are pulling and your foot is not on the pedals?
>>>> and 2)  is
>>>> there a way to make the two (2) larger NACA scoops on
>>>> top and in the
>>>> back for the engine cooling from the existing fuselage
>>>> or do you
>>>> really need to buy the pre-fabricated ones from
>>>> Velocity?
>>>>
>>>> Thanks!
>>>>
>>>> Rick Wallace
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>>>
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