---------------------------------------------------------- Europa-List Digest Archive --- Total Messages Posted Thu 06/05/14: 3 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 12:41 AM - Re: coolant thermostat uk (Frans Veldman) 2. 05:10 AM - Re: coolant thermostat uk (Remi Guerner) 3. 07:11 PM - Rosen Sunvisor System for Van's RV 6-7-9 (Kevin Klinefelter) ________________________________ Message 1 _____________________________________ Time: 12:41:05 AM PST US From: Frans Veldman Subject: Re: Europa-List: coolant thermostat uk -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 06/04/2014 02:37 PM, Nigel Graham wrote: > Your experimentation and the experience of coolant failure of > others begs an interesting question, if the Rotax air cooled > barrels do not offer any increased endurance in the event of > coolant loss - why use air-cooled barrels? Water cooled barrels > would offer far better heat distribution and thus less localised > distortion and allow tighter tolerance pistons that in turn would > develop greater power with less noise. The barrels don't need to radiate much heat. Over 90% of the heat of the combustion is transferred to the cylinder heads. This is where the combustion takes place. Once the piston is moving downwards the combustion has already ended and because of the expanding space temperature drops rapidly. The fins on the barrels are misleading. They look like the fins on the barrels of truly air cooled airplane engines, and make people think that the Rotax engine is partially air cooled. This is not so. True, a little bit of air helps to get rid of the residual heat of the barrels, but not much can be gained by increasing air flow over them. The barrels are also cooled by the cylinder heads and engine core. One end is water cooled, the other end is oil cooled. In my airplane I have closed off the gills AND the round openings at the front of the cowling. Air flow is guided with two hoses from a single opening which also feeds an oil radiator, and the air exits via the cowl flap which is shared with the radiator exits and is usually almost closed. With tuning the system I was amazed how little air flow is needed to keep the barrels within a healthy temperature range. In the original Europa setup, the rear most barrels have almost no air cooling, without adverse effects. Loss of coolant will almost certainly melt the engine. Although it seems that while the engine is running the softening barrels and heads will remain enough in shape by the pistons to keep power production up fow quite a while. Frans -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.22 (GNU/Linux) iQIcBAEBAgAGBQJTkCqFAAoJEC+zXxqs0ZzVh80P/2d4FjV8jDwIHr6barqWQGnA Z6IFEyM10EIOLUCB5WMjtKweqfFqPlb6t72YNMjJtTmqWt61NTU2rKJ79LjzJL41 ZizOKPzRlBOQHEDmEqBlWqXxrGIaO3O/B0sqolSET/IGqd+Kszh69MYOCJZgCFb3 2utSvVqxi1cpXpPaLRRE7vd5lWMjvM0F8XWa/LQ3uUDw+MRU26KhYSHa9iHtej3L UbQe3Q+yNqJ0tSMsa0P8IPv8ZQT6A97daU6m92ELwnFtqNtY5Gds+yGHKSOl6nr9 I/4yN51QSEGSQ+ttQRlGjoXH9nMOnHSBRFx5WIg+sw3DF4+7KH3DhPWwtb6d0rlR WrDNsS/MbK3fKtUeSnEn75FsbZ+4Zljn5vuGUtgu9wxQCqHQJ4dVq3jBspg1XKMW Ujn3QvS8w4C2WVUM0OfQxjh1IY97etWaUoMwAs0CCI7EBRHlzHsOwTTkMFV7XXx+ oAMn0soxrHRl9lTOD0Q5oTFCHH3RBq0LpdnZxmO+QWZU7aeDEYb3Yk/6SKLqQmxw BeV3fvKY2cOLp/GL7Di9wc0P5k46x5QGXzC1lD8k5r0v3DimHWIMtKuC1KwtP0b3 7wU2x4WxxZAInFpMwfR76WQZozYcqZKun6LHS7n8/+A10ckotEVjMPKWb4mF0YnK YkyW8xn5ZHGZu1jRUx2o =0IQT -----END PGP SIGNATURE----- ________________________________ Message 2 _____________________________________ Time: 05:10:43 AM PST US Subject: Europa-List: Re: coolant thermostat uk From: "Remi Guerner" This is confirmed by Rotax in the Installation Manuals: They state: "The size and type of radiator should be adequate to transfer thermal energy of approx. 28kW (912S) 30kW (914)". For the cylinder barrel, they say: "the cooling air ducts must be designed such that they transfer thermal energy of approx. 6 kW. " That means that up to 83 % of the cooling is done through the water-cooled heads. Obviously, in case of a total loss of coolant, the engine will not run for long with the remaining 17%. Remi Read this topic online here: http://forums.matronics.com/viewtopic.php?p=424389#424389 ________________________________ Message 3 _____________________________________ Time: 07:11:19 PM PST US Subject: Europa-List: Rosen Sunvisor System for Van's RV 6-7-9 From: Kevin Klinefelter This may be a nice fit in our aircraft as well as Van's. 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