Rob,
OK. I have the 3/4" lines and I mounted eyeballs on both the NACA and
the panel. Plus the passenger NACA has another 1/2" takeoff that goes to the
avionics stack. The NACA mounted vents are used to keep the lower body
cool as heat will eventually make its way through the firewall and the nose
wheel well even though the areas are covered with insulation. When fully
open the vents can create a tornado in the cockpit, reordering a nice stack of
charts and plates. The only drawback to those NACAs is the admission of
NOISE - prop, engine, slipstream and eagles screaming to get out of the
way.
BTW, vent efficiency is highly dependent on adequate cockpit air
exit. At 180 KIAS my cockpit is 300 feet higher than the aircraft altitude
and the exiting air is mainly down the elevator console/push rod tunnel and out
the openings in the vertical stabilizer that provide for elevator
movement. There is probably some canopy seal leakage also.
In the pix I sent you can see the foot well eyeballs in the bottom of the
left and right panel pix (the pix quality wasn't that great after it got cut
down passing thru the internet. It was 15C outside and the pilot panel
eyeball was almost closed and the passenger side was open but not pointed at
me. Also, that tube shown in the center console pic is used to reach the
foot well eyeballs for adjustment.
Grayhawk
PS I've flown in AZ - if you wear a snakeskin covered baseball cap and a
silver wristband you stay cool.
In a message dated 6/21/2010 7:21:34 A.M. Central Daylight Time,
rwolf99@aol.com writes:
Greyhawk -
Yes, my eyeball air hoses are 1.5 inch SCAT. Reports from earlier
Lancair builders suggested that the panel-mounted air vents provided
insufficient air. Many builders mounted the eyeball vents directly to
the sidewall NACA ducts to get more air. But you know all this -- you
were part of the early crowd.
The eyeball vents from Lancair came with a cap for a tiny,
tiny SCAT tube coming in from the side. Maybe 3/4 inch.
Small. I bought adapters from Jon Pastusek (also available from aircraft
spruce) which allowed a 1.5 inch SCAT tube to go directly to the back of the
vent -- no 90 degree turn required. I hope to have plenty of air.
If it's too much, I'll close it partway. But I live in Arizona now
and I suspect that I'll have it wide open.
- Rob
Wolf