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Jun 23, 2003, 10:29 AM
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dave morris's Avatar
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NACA inlet help


I want to get some airflow into my Minx and like the look of what I belive are refered to as NACA inlets. I sketched the shape that I recall, they push into the fuse in the rear rather than stick out in the front like a regular scoop. Any better pics so I can get a decent shape?
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Jun 23, 2003, 12:16 PM
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Jones Boy's Avatar
Dave

I know someone who plans to use this type of inlet on a Turbine model.

I beleive he has downloaded the data from a NASA site!

If you can't find it I'll see if he's willing to share.


Graham
Jun 23, 2003, 12:25 PM
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dave morris's Avatar
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thanks Graham, I did some research on the internet and found some examples used in full scale experimental designs, have been playing with the best way to execute them into an already finished fuse.
Jun 23, 2003, 12:50 PM
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Jones Boy's Avatar
Dave

Are you mean putting theory into practice thats where the hard work begins hey. Well good luck and keep us posted.

Graham
Jun 23, 2003, 04:01 PM
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davidfee's Avatar
Here are the coordinates for the NACA submerged inlet.

http://naca.larc.nasa.gov/reports/19...i?page0026.gif

-David
Jun 25, 2003, 01:41 PM
Registered User

Wattage F-86, Hook & NACA Duct


The bungee hook position and the detail of the NACA duct are shown in the belly view of the airplane, attached file Sabre3b.bmp, the duct lips were vacuum formed and attached over the cheater hole in front of the fan unit, as shown.
Jun 25, 2003, 05:44 PM
EDF rules... :)
AirX's Avatar
Dave,

Have you done anything with the NACA inlet?

Eric B.
Jun 25, 2003, 07:13 PM
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gkamysz's Avatar
A naca intake requires the "ramp" to function properly. Omitting this part is just as good as cutting any kind of hole. The picture attached above does not seem to have the ramp.

Greg
Jun 25, 2003, 08:14 PM
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dave morris's Avatar
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have not done anything yet , still looking at it. May end up putting in on the front top just before the canopy, dont really want to mess up the sides, and if I really screw it up I can fix the nose easier than the sides. Will have to research some more so I can understand the shape including the ramp a little better.
Jun 27, 2003, 09:43 AM
Registered User
My Wattage F-86 duct has no ramp. I measured static thrust with and without, with no difference noted. Since it didn't hurt static, I reasoned developing a vortex on the lips should help the air into the hole. Remember the inflow though the primary duct may act as a ramp. The other thought was that at speed, the air though the primary duct may be spilling out the cheater hole, so I thought at least I might inhibit this. Only the airplane knows the results, and there is no NACA data on such a combination. It is ugly!
Jun 27, 2003, 11:46 AM
EDF rules... :)
AirX's Avatar
David if I could decifer the low res picture of the coordinates, I would produce a model of it in AutoCAD that could be scaled up and down. Basicaly have someone put it onto a server for all to use.

Just cant read it good enough to use them.

Eric B.
Jun 27, 2003, 12:22 PM
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davidfee's Avatar
Eric,

I see what you mean. I just found that image on the NASA website and posted the link... but you're right that the coordinates are basically illegible. It would be easier to just trace the top and side views in CAD and forget the coordinates. I'm sure it would be accurate enough for our purposes.

-David
Jun 27, 2003, 12:38 PM
Registered User
Hi, Dave
I have a hard copy of Bede's design of a 'flush air inlet', aka a naca scoop.

in general, the descent angle of the surface (in case of a scoop on top) is 7 degrees. the entrance shoud have an aspect ration (width to hight of 3 to 5). from the hight of the entrance divided by the sine of 7 deg you get the length L. keep the shape some what like a tangent function (look at the pic).

if it's unclear (quite possibly ),I can scan it, but it would only be able on monday, or maybe sunday. if by tomorrow you don't get a decent photo, PM me and I'll scan it at work.


Avi
Jun 27, 2003, 03:18 PM
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dave morris's Avatar
Thread OP
thanks Avie, I think I can work with that, I have decide on putting it on the nose just ahead of the canopy. will post some pics when done (if it looks good, otherwise I will just do an old fashion plastic spoon regular scoop). My only other concern is will I get enough air out so I don't blow the canopy. Right now I have a small hole in the rear of the splitter right over the spinner center. I hope this will help pull the air out of the fuse.
Jun 27, 2003, 03:26 PM
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RickG's Avatar

Try this one...


This one is a bit easier to read. Can't make the image show here, but the link works...
Last edited by RickG; Jun 27, 2003 at 03:30 PM.


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