hi dene i put a jab 3300 in a murphy reagade i had the same problem to fix it increased the oil cooler size i then built a ram air box with six scat hoses of different sizes i connected the hoses to the firberglass cowling covers above the heads to check the temps on each cylinder i borrowed a thermo coopeler box most drag shops or hot rod type shops have them it is like a temp gauge that has up to eight head connecting points you can read all head and oil temps at the same time i found up to 50c difference between cylinders i increased or decreased hose sizes as required i can fly the plane at 50 kn or 90kn the temps stay in the green i also tow gliders with it and still in the green it is a bit of mucking but worth it when i got it wright i connected cht to the hottest cylinder i have about 10 degree difference between hottest and coldest you shoud also work on air inlet one third air outlet two thirds now have 500 hours with that set up i also fly in a hot country best regards russ ----- Original Message ----- From: "Dene Collett" <av...@telkomsa.net> To: "KRnet" <kr...@mylist.ne Sent: Saturday, December 05, 2009 6:18 PM Subject: KR> New subject
Hi guys As I only download email every three days or so, I have to sit and sift through a lot of e mail to find the interesting stuff. I consistently find certain subjects rehashed over and over so I thought I would start a new one. I would like to start a thread on cooling systems or rather the theory of cooling systems. I have been battling for months now to get a 3300 Jabiru to cool correctly in a Whisper motorglider. I have been through three different incarnations of cowl/cooler setups with little success. Either the cylinders cool sufficiently at the expense of the oil temps or vice versa. I have come to the conclusion that because of the low speeds obtained by the plane, it is no use looking at other GA aircraft for ideas for outlets. I think that in general motorgliders and low speed aircraft in general use more ram air cooling and just make their inlets big enough to allow enough air to pass through. The outlet is just a big hole at the bottom of the cowl. I have tried ducts that can be closed during gliding to minimize drag and shock cooling but with little to no success. Unfortunately I do not have any education in aerodynamics or fluid dynamics so I am going by real world experience and testing. Lets get a thread going here so we can all learn something. Regards Dene Collett Avlec Projects cc Port Elizabeth South Africa _______________________________________ Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net please see other KRnet info at http://www.krnet.org/info.html
