Fresh air intake ducts

NACA adjustable intake 76mm

  • Updated version for 2022
  • Excellent air flow due to true NACA shape and clean duct design
  • Fitted with just 4 flush-head screws, although an edge sealant can also be used.
  • 6061 Al flap can be painted or polished to match the aircraft
  •  Air outlet is aimed about chest-high for best cooling without having to add eyeball vents
  • Coarse thread controller – only 3 turns open to closed
  • Low drag when open, no drag when closed
  • Mass of assembly is only 80 grams (3 ounces)
  • Vents are 3-D printed in PLA, a plastic that is impervious to many solvents but is bio-degradable.
  • Supplied in carbon fibre reinforced PLA or various colours.
  • Can also be supplied with 1 ¾” and 2” round outlet for connection to eyeball vents.

Clean internal design for maximum air flow

Other styles:

These will all be supplied in the new low profile design.  Note that the 76mm NACA vent cannot be retro-fitted with the original Sonex style cutout.  See the 87 mm vent below.

Price: A$65 each

NACA 76mm intake with outlet deflector

As above but allows some adjustment of the outlet direction.

Smooth internal flow and adjustable outlet

Price: A$70 each

NACA adjustable intake 87mm  (15% larger)

All the same features as the above vent but the cutout envelope is large enough so that it can be retro-fitted by enlarging the original Sonex style cutout.

  • Excellent air flow
  • Mass of assembly is only 100 grams (3.5 ounces)
  • Carbon fibre reinforced PLA (shown).  Other colours available.

Price: A$70 each

When I built my Sonex, one area where I followed the plans exactly was the shape and location of the cabin air inlets.  As most Sonex builders know, they are inadequate for a warm climate, which led me to design the first of my air inlet ducts.  They worked quite well so I also made an improved design that was a true NACA shape.  Only problem is that I couldn’t retro-fit them to a Sonex like mine that had the original cut-outs so I made a duct that is 15% bigger than the original NACA duct.  The cut-out envelope for this duct is large enough to completely enclose the original Sonex cut-out.  Once again, my Sonex was the test bed.  How well does it work?  The answer is GREAT.  It’s almost a howling gale with it fully open.  

NACA adjustable intake 114mm (50% larger)

These are also fitted with an outlet deflector to allow adjustment of air flow direction.  The main body is vacuum formed ABS.  Outlet is 3D printed PLA, carbon fibre reinforced as shown.

These are probably more suitable for lower performance aircraft as they shift LARGE volumes of air, even at low speed.  The main application for these vents has been providing cooling for velomobiles.

Michael Urquart’s velomobile

Price A$85

Sonex intakes

These are not a true NACA shape but are designed to fit the original Sonex intake cut-out.

  • Greatly improved airflow over the standard intake
  • Fitted with just 4 flush-head screws, although an edge sealant can also be used
  • 6061 Al flap can be painted or polished to match the aircraft
  •  Air outlet is aimed about chest-high for best cooling without having to add eyeball vents
  • Coarse thread controller – only 3 turns open to closed
  • Low drag when vent is open. No drag when vent is closed
  • Mass of assembly is only 104 grams (3.7 ounces)
  • Can be supplied in carbon fibre reinforced PLA or a variety of colours
  • Updated model has lower profile and higher strength control screw and nut than earlier models.

    Price:  A$65 each

NACA intake – non adjustable

These are a normal NACA intake with 1.75″ round outlet for connection via scat hose to an “eyeball” vent.  These are available in either “straight” or 45 degree angled.

Straight vent

 

45 degree vent outside view

 

45 degree vent inside view

 

Other colours available

Price:  A$40 each