> Its a little uncomfortable when its 26/27 deg. I was
> wondering if anyone has any suggestions for more cooling.
Our solution to this problem is a bit simpler than some that have been
described, but we find it quite satisfactory, even when the summer
temperatures here in California top 100F/40C. We installed the NACA
inlets (supplied with the kit) higher than the location shown in the
fuselage side. We then formed a fiberglass duct, about 4 or 5 inches
long, from the outlet of each NACA inlet to a (roughly) 2-inch square
plate, which is mounted slightly above and aft of the NACA inlet, facing
generally toward the pilot (or passenger). Swiveling "eyeball" air
outlets mounted in these plates allow the air to be aimed as desired, as
well as adjusting the flow volume. (We normally leave the NACA inlets
open all the time.) It takes a bit of fiddling to find a spot that
doesn't interfere with the instrument module, won't intrude on knee
space, and still clears the door surround, but it can be done. A slight
draft comes through from prop wash on the ground, but an elbow out the
door is the best solution while taxiing. While it certainly isn't cool
in the cockpit when the outside temperature is extremely hot, I don't
think I would want a stronger wind from the vents in any case. Better
to climb a few thousand feet instead!
A possible drawback to this arrangement is that air exiting the louvers
in the top cowling seems to be forced downward by the high pressure at
the base of the windscreen, so it can enter the cabin air inlets. (I
don't know if this happens to some extent with the inlets in the
standard location also.) We had serious problems with the original
exhaust system supplied with our kit, causing exhaust to be dumped into
the cowling. This led to a slightly elevated level of carbon monoxide
in the cockpit, which we measured at 35ppm directly behind the air
inlets. This would comply with current standards for certified
aircraft, I believe, but we were not satisfied. Fortunately, the
modification we made to improve cooling air flow around the engine
(baffling off the space between the footwells and blocking 3 of the 4
louver slots on each side of the cowl) also sweeps any exhaust leakage
out the bottom rear exit of the cowl. Though our replacement exhaust
system doesn't normally leak, the ball joints sometimes fail to seat
again when the springs stretch on a hard start, resulting in severe
leakage. Worse still, I returned from Phoenix a few weeks ago to find
lead deposited all around the exhaust opening in the cowl and many other
nearby areas. The muffler had cracks all around the brackets holding
the aft sockets, and there was a 2-inch long split in the seam around
one end cap. In spite of this extreme leakage, the CO monitor never
rose above 0 ppm, so we are confident that no amount of CO in the cowl
will expose the occupants to hazardous levels.
Dave DeFord
N135TD
|