Hi Dene We had simular problems on a Zenair. No matter how big a lip we put on or how big the cowl exit it would overheat. My opinion was that the shape of the cowl and the underside of the aircraft caused a high pressure area at the cowl exit underneath.
We put vents (like gills) on the side of the cowl for a 20 degree Celsius drop in temperature. All Good :-) Regards Barry Kruyssen k...@bigpond.com http://athertonairport.com.au/kr2 RAA registered 19-3873 Australia -----Original Message----- From: krnet-boun...@mylist.net [mailto:krnet-boun...@mylist.net] On Behalf Of Dene Collett Sent: Monday, 7 December 2009 3:24 PM To: KRnet Subject: Re: KR> 3300 Jabiru to cool correctly I have tried all kinds of lips of various sizes at the exit to no avail. I also have an in flight adjustible flap that hinges down to open and close the exit which forms a hige "lip" when in the full open position. It also has sides as we thought the air being displaced by the flap was spilling round the sides of the flan satisfying the low pressure at the mouth of the exit...... no luck. The air inlets were sized the same size as the four seater Jabiru aircraft which uses the same motor. What was not taken into considderation was the fact that the motorglider flies at a much lower airspeed than the Jabiru. My next experiment is to enlarge the inlets and see what difference that makes. Regards Dene Collett Avlec Projects cc Port Elizabeth South Africa
