---------------------------------------------------------- Europa-List Digest Archive --- Total Messages Posted Mon 12/04/06: 4 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 03:22 AM - Re: Cooling diffuser (Graham Singleton) 2. 07:49 AM - Re: Cooling diffuser (Rob Housman) 3. 10:38 AM - Preliminary exhaust augmentation mockup (GLENN CROWDER) 4. 01:16 PM - Re: Perfect cooling diffuser (karelvranken) ________________________________ Message 1 _____________________________________ Time: 03:22:15 AM PST US From: Graham Singleton Subject: Re: Europa-List: Cooling diffuser Ron I will attach a pik. Problem with Europas is the gases can get sucked into the cabin, but that could be cured I'm sure. Graham rparigor@suffolk.lib.ny.us wrote: >Hello Graham > >"> Another way to improve cooling on the ground is exhaust extraction, >this > > >>is how the EZ boys do it. I don't think anyone has tried it yet on a Europa." >> >> > >How exact is exhaust extraction accomplished on EZ? > >Ron Parigoris > > > ________________________________ Message 2 _____________________________________ Time: 07:49:08 AM PST US From: "Rob Housman" Subject: RE: Europa-List: Cooling diffuser In re: water spray It's been a long time since I studied heat transfer but I recall enough of the principles (if not the details) to know that there are a couple of conflicting factors with this proposal. On the plus side, a fine mist of water will provide some evaporative cooling, since the phase change from liquid to gas will remove much more heat than liquid water flowing through the air spaces in the "radiator" (a heat exchanger in engineering speak). Also on the plus side is the fact that heat transfer to water is more efficient than heat transfer to air. So far, so good. The big negative here is the impediment to air flow - put any amount of water in the spaces where the air is supposed to flow and less air can flow resulting in less efficient cooling. It's worth a try but I expect that spraying water will cause coolant temperature to rise not fall. Best regards, Rob Housman A070 Airframe complete Irvine, CA -----Original Message----- From: owner-europa-list-server@matronics.com [mailto:owner-europa-list-server@matronics.com]On Behalf Of rparigor@suffolk.lib.ny.us Sent: Sunday, December 03, 2006 9:43 PM Subject: Re: Europa-List: Cooling diffuser Hello Graham "> Another way to improve cooling on the ground is exhaust extraction, this > is how the EZ boys do it. I don't think anyone has tried it yet on a Europa." How exact is exhaust extraction accomplished on EZ? How about spraying water on the radiator during extended ground operations and temps creep high, anyone try this? Ron Parigoris ________________________________ Message 3 _____________________________________ Time: 10:38:46 AM PST US From: "GLENN CROWDER" Subject: Europa-List: Preliminary exhaust augmentation mockup I have been working on and off (mostly off) on an exhaust augmentation system for my EA81 powered monowheel. The idea is to use the waste heat of the exhaust to do the cooling for you instead of using high drag ram pressure thru the rad. The Reno racers do this and claim it adds up to 20 mph while improving cooling. Inlet duct areas can be dropped to almost nothing as the augmenter creates a huge suction effect to suck cooling air thru the rad from behind. Racers who have used this arrangement report up to 4 inches of suction. A standard flow thru ram type duct arrangement typically only gives an inch of pressure difference even if done well. Theoretically, one could reduce the rad size dramatically as a result, saving more weight and drag (maybe by half or more). The engine exhaust pipe will enter the duct at the big bulge and terminate about 6 inches inside the duct. This then creates a high speed jet of exhaust that mixes with the back side radiator air and the mixing creates an enormous suction on the back side of the rad. It all fits very snug and the long oval shaped tube tucks in right beside the monowheel. It looks heavy but the kevlar tube is only a pound and the fiberglass duct is only a pound, replacing the rear duct I already use. I have one radical idea that I will try and that is to not use a front difffuser duct at all, and just let the radiator suck air from the inside of the cowling. Hopefully, that would be near zero cooling drag. Ground cooling is claimed to be excellent as well, as cooling is entirely determined by engine rpm, not airspeed. One should be able to run WOT on the ground as long as desired without overheating as suction is doing all the work, not ram pressure. Also, reports are that the long mixing tube only gets warm to the touch. The system should be peaches on a 912/914 powered unit as well although you would need a 4 into 1 type exhaust. Glenn _________________________________________________________________ Get free, personalized commercial-free online radio with MSN Radio powered by Pandora http://radio.msn.com/?icid=T002MSN03A07001 ________________________________ Message 4 _____________________________________ Time: 01:16:19 PM PST US From: "karelvranken" Subject: Re: Europa-List: Perfect cooling diffuser Glenn, The duct inside isn't part of the cowling. I made it of carbon tissu, it looks like a black hole, but be sure it is perfectly sealed on the radiator. The radiator also is modified, no more the square block but a 4 cm thick one of 26 cm x 15 cm = 390 cm2. Karel Vranken. ----- Original Message ----- From: "GLENN CROWDER" Sent: Monday, December 04, 2006 2:49 AM Subject: Re: Europa-List: Perfect cooling diffuser > > That looks awesome Karel! ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message europa-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/Europa-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/europa-list Browse Digests http://www.matronics.com/digest/europa-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.