Thread: NACA type airbox intake

Not directly RV related but thought there may be a few people here who had done this or seen it done or had an opinion on the idea. I am looking at using this NACA style scoop as an intake to a filtered airbox (its actually for a Pitts Special - carburated O-320). It will be placed in the usual place, about 1ft below the spinner with the narrow portion towards the top, the intake hole is 2.5". With the slope of the cowling the intake...

It might work (only sue to its location) -- but this type of intake does not generally produce any MP increase on piston engine intake systems due to 'ram effect'. You would be better off with a scoop sized to about 2x the fuel controller throat area, and try to include an expansion area that allows the air to slow a bit, but it would seem to me that this won't be possible in this particular installation... That is a nicely done...

I recently installed a similar inlet up towards the front of my RV7A. Results are not great but I do think I am getting a bit of MAP increase from it. I was able to form mine in such a way that the opening is straight in, the air does not have to turn. I plan to experimt with the installation of a "helper scoop" to see if it increases the MAP any. I have seen 30.5" down on the deck at speed. My inlet air foes through...

I like the looks of this for use in place of the white plastic Van's NACA scoop...would it fit as a direct replacement in the appropriate locations on the side of the fuse in a -7? (That is, are all NACA scoops identical, I guess?) Quote: Originally Posted by Dragonfly Not directly RV related but thought there may be a few people here who had done this or seen it done or had an opinion on the idea. I am looking at using this NACA style...

I started my career at Hawker Siddeley in Kingston, one chap who was very knowledgeable on air intakes dismissed the NACA duct as a way of getting significant amounts of air inside an aeroplane. His view was that any intake worth its name must stick into the airflow and grab some air - otherwise you just don't get any mass flow down the intake. If he was pushed further his opinion was that most 'NACA ducts' that he had seen...