Ed Cesnalis Posted May 9, 2014 Report Share Posted May 9, 2014 What seems to be the case is that we can see lower rpm & fuel flow for a given speed - so with the price of fuel over here I tend to look to cruise between 105 & 110 kts - which I get with about 4500rpm and ~17 litres/hour I tend to fly with two up (neither of us elfin thin) so with enough fuel to go somewhere we are usually at or very near max weight which does have an appreciable effect for a given power setting. I think 130 kts is a tad optimistic - vne is 145! Next time I'm out I'll just see what we can get straight & level with prop in full coarse and the throttle fully open. Certainly the -12 flaps is advantageous though. Prop at full coarse will limit RPM / Power / Speed. Your fastest setting will be where you get 5,500 RPM and WOT Full coarse and WOT sounds hard on the motor. Link to comment Share on other sites More sharing options...
Ian Posted May 9, 2014 Report Share Posted May 9, 2014 Prop at full coarse will limit RPM / Power / Speed. Your fastest setting will be where you get 5,500 RPM and WOT Full coarse and WOT sounds hard on the motor. Yes, you are right of course - the best speed will be achieved when the optimum power output from the engine is coupled with the greatest thrust from the prop. Generally we don't fly fully coarse - we find one or two notches away from that gives the best performance - remember I'm usually looking for the best "economic" cruise. Link to comment Share on other sites More sharing options...
Ed Cesnalis Posted May 9, 2014 Report Share Posted May 9, 2014 Best speed is found at lightest weight, 7,500', 5,500RPM, WOT, vents closed, flaps reflexed Link to comment Share on other sites More sharing options...
Anticept Posted May 9, 2014 Report Share Posted May 9, 2014 Best speed is found at lightest weight, 7,500', 5,500RPM, WOT, vents closed, flaps reflexed Polished and waxed airframe, wheel fairings on, 400-4 tires, properly trimmed, dry standard temp day I'm sure there's more! Link to comment Share on other sites More sharing options...
FlyingMonkey Posted May 9, 2014 Report Share Posted May 9, 2014 Polished and waxed airframe, wheel fairings on, 400-4 tires, properly trimmed, dry standard temp day I'm sure there's more! Pilot leaning forward? Link to comment Share on other sites More sharing options...
Ed Cesnalis Posted May 9, 2014 Report Share Posted May 9, 2014 Pilot leaning forward? Lean back for best speed, it relieves the need for negative lift. Link to comment Share on other sites More sharing options...
Anticept Posted May 9, 2014 Report Share Posted May 9, 2014 You want the CG as close to the center of lift as possible while still controllable, so it would be pilot leaning back. Link to comment Share on other sites More sharing options...
207WF Posted May 26, 2014 Report Share Posted May 26, 2014 Oh, and minimum fuel, of course. WF Link to comment Share on other sites More sharing options...
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