Charlie, The following data can be forwarded to the VAF thread as you see fit: The data are averages for stabilized cruise portions of cross country flights with a single 7x16.5x2.25" radiator core in a belly mounted scoop. The Altrak altitude hold was engaged and the data was recorded by the Dynon EFIS and EMS at 3 second intervals. The stock cooling air inlets were blocked with flat foam plugs with about 2 sq in openings in each to supply some air flow through the cowl. RV-6A, wheel and gear leg fairings installed. Mazda 13B engine, normally aspirated. RWS RD1A PSRU, 2.18:1 reduction ratio. Warp Drive HP propeller, 3 blade 68" dia, 16.5 degree pitch at tip. Belly mounted scoop for cooling, containing coolant radiator and oil to coolant heat exchanger, variable air outlet. Auxiliary coolant radiator in cowl, thermostat controlled coolant flow, variable air inlet. Stabilized cruise averages: date 8/15/2015 8/15/2015 8/16/2015 duration (min) 20 40 70 ALT (ft) 9530 11530 10593 DA (ft) 12446 14294 13078 OAT (deg F) 69 59 59 MAP (in Hg) 20.8 19.2 19.0 RPM 5747 5712 5591 CAS (knots) 116 112 112 TAS (knots) 145 143 141 FF (gal/hr) 8.75 8.15 7.76 wt (lb) 1745 1715 1710 Coolant T in from cowl rad (deg F) 177 164 125 Coolant T in from scoop rad (deg F) 184 181 179 Coolant T out (deg F) 190 187 185 Oil T out (deg F) 226 222 216 Oil T in (deg F) 205 202 198 As possible point of interest, a more recent test flight with a V shaped radiator with two 7x16.5x2.25" cores in the scoop was made. In the cruise condition with a 114 degree F air temperature rise through the scoop radiator, the aircraft TAS was 143 knots and the scoop outlet air velocity was measured to be 157 knots TAS. Steve Boese RV6A, 1986 13B NA, RD1A, EC2-- Homepage: http://www.flyrotary.com/ Archive and UnSub: http://mail.lancaironline.net:81/lists/flyrotary/List.html