MAX A/C Cooling
with AirFlow Systems Light Aircraft Air-Conditioning
I was approached by RV-1O Builder Jason Merritt to assist with the installation of his Air-Con unit.
Jason lives and operates in Central Australia and the brief was to install the most effective A/C unit we could.
I already have an Air Flow Systems A/C in my own aircraft and although it works well, the Aerosport Roof Console has been the largest stumbling block with free air delivery being heavily restricted by the rear bulk head and the vent system . What works extremely well with Ram Air @ over 160 knts ,does not work well with a scroll fan that most A/C units use.
In my own aircraft I added a 4” Axial fan to pressurise the delivery at 2 psi, this has helped a lot however at the cost of more weight and power requirements.
We tried many options to increase airflow delivery, external ducting, side vents and Axial boost fans but what we stumbled across was the old axiom that simpler is nearly always better.
While testing the massive 300 cfm Evap unit that Airflow Systems sells, I found that by reversing the delivery unit and letting the Scroll fan blow straight in the cabin, angled up,it deliverers a MASSIVE amount of air at a good velocity along the roof of the aircraft where it hits the windscreen and then flows down over the body of the Pilot and Co-Pilot.
So, Introducing VH-BKK
With the A/C unit now reversed I needed to design an effective intake air system. I originally tried only two intakes but still found a drop in RPM so a third was added.
The net result is that the cabin air is circulated at a very high rate with each cycle getting cooler.
(This unit is 1 ½ kg lighter than my unit. my total system including Compressor was 23 kg so VH-BKK is 21 1/2 kg)
A lot of work was put into lowering the compressor into the cowl to make the L/H Cowl intake as unrestricted as possible. New Idler extensions and compressor spacers were made. Bill at Airflow Systems said he will be adding the required extensions and spacers to those builders who require them.
Spacing the A/C compressor outwards by 7/16” and using the new longer idler arm meant a new longer belt was required and a relief cut into the lower cowl.
Before Lowering Compressor ...
....and the new Compressor location.
The intake ramp was modified and the removable rubber transitions were added.