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NACA vent for overhead console

Bill.Peyton

Well Known Member
I need a recomendation in regard to sizing the NACA scoops for the Aerosport overhead console. I see that aircraft spruce offers numerous size options. Also, looking for a location on the Tail Cone to locate the vent. I don't have my fuse kit yet, but want to get started with the vent
Bill
 
I need a recomendation in regard to sizing the NACA scoops for the Aerosport overhead console. I see that aircraft spruce offers numerous size options. Also, looking for a location on the Tail Cone to locate the vent. I don't have my fuse kit yet, but want to get started with the vent
Bill

Just get them from Van's.....

NACA low drag sidewall mount hose interface
Part Number = VENT SV-1
Price = $6.25

This is the same part that you'll also have up front in your fuselage. There's no rush to put them on. The top skin is the last thing you'll put on the fuselage, so you'll have easy access through 95% of the build.

bob
 
Agree with Bob L. - just use the NACA vents from Van's. Putting them at the same level as the static ports in the forward most bay of the tailcone works very well and is a short run to feed an overhead console.

Bob
 
Do you need to install two naca ducts or just one? I was just hooking mine up and wondering about this same thing when the post came up!
 
The Vans price is a lot less then the others, so it sounds like a good plan to me. I just looked at their web site. I guess I should have started there! How far in front of the static vent did you place the vent? J, I am using 2 vents and the Aerosport vent control system.
Bob, I just looked at your last kitlog post. When the snow is on the inside of your hanger, you know you need a warmer hanger or bigger heater!!
 
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Do you need to install two naca ducts or just one? I was just hooking mine up and wondering about this same thing when the post came up!

Need - one will work, but this conversation has come up before. I don't know anyone that just installed one. I guess most of us prefer symmetry .

How far in front of the static vent did you place the vent? J, I am using 2 vents and the Aerosport vent control system.

No right answer to this one. Some have put it right behind the baggage bulkhead. (Like I did shown below) Others have centered in that section. My reasoning was to allow ample space for the duct to make the u-turn back to the bulkhead. The static port is much further back.

FP16112010A000RN.jpg


Bob, I just looked at your last kitlog post. When the snow is on the inside of your hanger, you know you need a warmer hanger or bigger heater!!

The snow disappeared pretty quickly once I turned on the heater. It is a curious thing how the snow stacked up like that on the door frame, but no snow was on the floor. While I was working and it was snowing harder, I couldn't see how the snow was getting into the hangar. I'm sure I'll figure it out before the winter is over.
 
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Thanks Bob. My fuse and wing kits are supposed to arrive next week, so it looks like I will put this off for a while. I wish I had thought of this sooner when I needed something to work on!
Bill
 
Rear NACA Vents

I am trying to avoid fiberglass sanding.
Decided to post some pics instead.

IMG_1336.JPG


The NACA scoops are positioned to allow unkinked routing and unfettered acces to the rear of the tail cone.

IMG_1337.JPG


IMG_1338.JPG


34 inches from the rear of the scoop to the static port.

IMG_1340.JPG


Vent control installed in the panel. Even though the controler has an off position it is only off in the open or close position, whichever you choose to program. I decided to install an on off switch so that the unit could be turned off in any position.
 
We put the same ones that came with the fuselage in the back as shown above and they worked great.
 
I'm really curious how an inlet just past the widest portion of the fuselage will work. Typically the air speeds up around the cabin, causing the pressure to drop, then it starts to increase towards the tail. That's why if your static port is too far forward just behind the widest part of the fuselage it will get lower pressure making your IAS high, and it needs to be mounted farther on back where the pressure is higher. For instance my cabin air outlet is mounted just behind the canopy in the top of the fuselage where the diameter is decreasing which is a low pressure region giving me good outlet flow up past my face.
My friend had his faux-NACA cabin air ducts mounted on the side of the fuselage just above the leading edge of the wing. They were totally useless as this is a region of very low pressure. If you have one of these faux-NACA ducts for your cabin air and you aren't getting much flow put two small VGs at the forward part of the duct toed-in toward each other.
The Relentless NXT had the same problem 'til I had Kevin put an air inlet at the base of the canopy windshield. He couldn't believe how much more flow was coming in through this 3/4" hole!
Since the air pressure inside a cabin is generally below static pressure, having an outlet near the tail where the pressure gets back to static doesn't seem to me to be the way to get good flow, as from a low pressure to a high pressure. I know of several people who noted that in the winter they would get cold air flowing forward from the fuselage cutouts around the elevator spar and into the cabin near the console, and they had to seal around the rear bulkhead and console to stop it.
 
I'm really curious how an inlet just past the widest portion of the fuselage will work. Typically the air speeds up around the cabin, causing the pressure to drop, then it starts to increase towards the tail. That's why if your static port is too far forward just behind the widest part of the fuselage it will get lower pressure making your IAS high, and it needs to be mounted farther on back where the pressure is higher. For instance my cabin air outlet is mounted just behind the canopy in the top of the fuselage where the diameter is decreasing which is a low pressure region giving me good outlet flow up past my face.

Not a problem on the RV-10 if you install the NACA vents in the area that is being discussed. I'm not sure if anyone has done a test to see if the flow is the same on the left or right, but there is plenty of airflow.

I know of several people who noted that in the winter they would get cold air flowing forward from the fuselage cutouts around the elevator spar and into the cabin near the console, and they had to seal around the rear bulkhead and console to stop it.

You do need to ensure that all your switches, etc installed in the overhead are sealed well. Becuase the overhead will pressurize, you will quickly learn where the components that aren't sealed well are located.

For those of us that live in colder climates, you may want to use one of these from Aerosport Products.

naca2.jpg

It will allow you to completely close the vents and gives you greater flexibility in the amount of airflow you get in the cabin. Most eyeball vents don't 100% stop the airflow.

bob
 
Is that your outside air temperature probe in your NACA vent?
Rear NACA Vents

I am trying to avoid fiberglass sanding.
Decided to post some pics instead.

IMG_1336.JPG









Vent control installed in the panel. Even though the controler has an off position it is only off in the open or close position, whichever you choose to program. I decided to install an on off switch so that the unit could be turned off in any position.
 
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