flyrotary@lancaironline.net Mailing List Archive

Thanks Steve I always appreciate your scientific understanding and explanations. Much appreciated. Steve > On 30 Nov 2020, at 1:34 am, Steven W. Boese SBoese@uwyo.edu <flyrotary@lancaironline.net> wrote: > > Steve, > > Your cooling system is a closed system with two heat exchangers, one being the engine adding heat and the other being the radiator removing heat. The delta T of the coolant across the engine and the delta T across the radiator must be the same. Since there isn't much you can do to change the characteristics of the engine as a heat exchanger, there isn't much you can do to change the observed delta T. > > As you change the characteristics of the radiator side of the system, the inlet and outlet temperatures will change together until a steady state is reached and the radiator can remove the amount of heat produced by the engine. With increasing power, both the inlet and outlet temperatures will rise by the same amount until the mass air flow through the radiator together with the OAT results in the required amount of heat removed from the system. The goal is to keep the average of the inlet and outlet temperatures within reason. Delta T by itself isn't a good indicator of the suitability of the radiator side of the overall system. > > This all assumes that a thermostat isn't being used. With a thermostat, the delta T across the radiator will be variable until the bypass is completely closed, at which point the above behavior will be seen. > > The attached plot shows the effect of changing the air inlet and outlet sizes but the delta T is essentially constant. > > > Steve Boese > RV6A, 1986 13B NA, RD1C, EC2 > > From: Rotary motors in aircraft <flyrotary@lancaironline.net> on behalf of Stephen Izett stephen.izett@gmail.com<flyrotary@lancaironline.net> > Sent: Sunday, November 29, 2020 1:08 AM > To: Rotary motors in aircraft <flyrotary@lancaironline.net> > Subject: [FlyRotary] Water Temps > > ¡ß This message was sent from a non-UWYO address. Please exercise caution when clicking links or opening attachments from external sources. > > > Hi there people > > Has anyone got data of actual delta T from inlet to outlet of their water radiators > And if you do, what is the size of your inlet feeding the radiator, IAS and OAT at those data points. > > We have ~30 square inches of air into the water cooling > Water into the engine is these data points was 180F > > Delta T KIAS OAT > 10F 153 54 > 8F 115 54 > > I¡¯m now fine tuning our water cooling and wanting to compare with other known data. > > Thanks > > Steve Izett > Glasair SuperIIRG Renesis 4 Port > > > > > -- > Homepage: http://www.flyrotary.com/ > Archive and UnSub: http://mail.lancaironline.net:81/lists/flyrotary/List.html > <inlet and outlet area comparison s.jpg>-- > Homepage: http://www.flyrotary.com/ > Archive and UnSub: http://mail.lancaironline.net:81/lists/flyrotary/List.html