Anyone ever use NACA ducts?

[Paddletrucker]

IT seems a lot of folks have done some pretty extreme mods to deal with heating issues. Some of the mods are really cool and look good, too. I see hood scoops of different kinds, and other sorts of things.

In homebuilt airplanes, and just planes in general, we deal with heating issues since most piston powered aircraft engines are air cooled. We have to find a way to duct air around the cylinders and also to bring air into and exhaust air out of the cowling. I don't know if this is true with a Jeep, but in a plane, exhausting the cowling can sometimes be as important as scooping air in.

One of the most popular ways to move air from outside the airplane to inside is the NACA duct. It's also used extensively to bring fresh air from outside into the cabin. Small planes are rarely equipped with A/C, so outside air is important. These NACA ducts are also really good for this.

Okay, so what the hell is a NACA duct? Well here 'ya go.
http://en.wikipedia.org/wiki/NACA_duct

And you can buy them, but they are a little pricey.
http://www.aircraftspruce.com/catalog/appages/nacascoop.php

So what I was wondering was if anyone had used these in the hood or maybe even the inner fenders of an XJ for cooling or venting the engine. IT would be quite a bit of work and expense for an experiment, but I have yet to see pictures of these imbedded in the hood of anyone's XJ.

If I have any heating issues with my XJ, I might give this a whirl, just to be different. On the Wikipedia page, there's a picture of a red sport's car with NACA ducts incorporated into the hood. I think it looks pretty sweet and not something you'd typically see on a Jeep.

Thoughts?

[BlueXJ]

Those are the type used in the past on Camaros. I have not seen them in use on a Jeep, but the reason, I would surmise, would be the slow speeds at which we get the diminished airflows. The advantage that aircraft has is that slower speeds also cause stall problems. A slower speed would entail a loss of lift across the wing, thus stall and then mean old Mr. Gravity takes over.
If we drove our Jeeps only at speed then airflow would cease to be a problem.

[XJ Rat]

They look good. But is not this vent style made for high speed? Maybe they would work good on a Grand Cherokee SRT8, but they would look good on an XJ.

[nota944mechanic]

They look good. But is not this vent style made for high speed? Maybe they would work good on a Grand Cherokee SRT8, but they would look good on an XJ.

Actually, NACA ducts will still work well at lower speeds. Formerly, I built and maintained Porsche race cars for ALMS, GrandAm, HSR, NASA, and Porsche Club events. We stored the customer cars in a warehouse just down the street from our shop. One car, in particular, had a NACA duct in the passenger side quarter window with a 3" hose that was pointed at the driver's face. I couldn't believe how much airflow that little duct provided at the 35mph speed limit.

I think the big issue with installing these is their size. NACA ducts tend to take up a lot of space, and our engines are fairly close to the hood. This might make it tough to mount them somewhere that was actually beneficial.

[LizardRunner]

I am currently making forms for some NACA ducts for my hood, then I'll be hammer forming the sheet metal and doing the welding. These will be reverse ducts, mounted so that air from the radiator fans will vent out the hood, thus allowing much more flow through the radiator. There's a thread on here somewhere that I put photos of some store bought NACA ducts. The NACA duct will flow great quantites of air even at speeds as low as 15 mph. Once I get these finished and installed, I'll be posting pictures and maybe even a how too.