"You will probably see 250 mph with pants and 200 hp" It doesn't work like that in the air, like adding HP to a car and expecting speed increases. Mark's climb rate will definitely get a BIG jump, possibly the best in the bunch so far, if he can match a prop to it. But increasing HP does little to increase cruise or top speed after a point, especially for planes flying at or near 200 mph and up.
Back a few months ago we discussed this at length, and all who have studied on this have agreed; more is gained by drag reduction than HP increase. To double the speed, drag is increased by 4 times. To get 250 mph from a KR2S, one needs to lose the front wheel, or work very hard on a completely aerodynamically faired leg, not just a cover, and the same holds true for the mains, and their legs. Now anything sticking out in the breeze becomes important; so that round strobe Mark has will have an impact at these speeds; any antennae should have a fairing, not just be left round; wing root fairings need special attention due to this area relating heavily to the highest lift area on the wing so also potentially the highest drag area; cowl flap(s) become a consideration to reduce drag; greater rake to the vertical stab, etc... "Speed with Economy" is definitely the bible here... There are a lot of pluses to using the Mazda 13B in aircraft with firewalls designed for their weight. But without alot of reinforcing, similar to the refit rebuild that the KR360 got, I think the Mazda is too heavy, and high output. Better to use a different engine with slightly less HP but just as much torque after the re-drive and stay with what your firewall/airframe can handle... JMHO... Colin Rainey brokerpi...@bellsouth.net N96TA
