Shadrach Posted January 29, 2019 Report Posted January 29, 2019 1 minute ago, KLRDMD said: I'm sure if I pulled the power back to 150 KTAS the fuel flow would be much less but are you getting 170 KTAS in your F model at 12.5 GPH ? 1:2 seems fairly consistent. Every 1% increase in speed takes a 2% increase in fuel. In my 231 every 3% increase in speed cost 6% more fuel. That extra useful load of 75 lb that the Bonanza has over an F or 225 lb increase I had over my 231 really makes a difference for some people, me included. No...I was going by the pic you posted with a TAS of 162 at 11.5gph LOP. So consider me amazed by the efficiency of your Bonanza. 23% more frontal area, 2 additional cylinders to feed and yet only 1.4nmpg less while going 20kts faster. I take back my earlier comments about efficiency as I don't think my bird would go 20kts faster if I could put the 2.5 more gph through it. Quote
KLRDMD Posted January 29, 2019 Author Report Posted January 29, 2019 Just now, Shadrach said: No...I was going by the pic you posted with a TAS of 162 at 11.5gph LOP. So consider me amazed by the efficiency of your Bonanza. 23% more frontal area, 2 additional cylinders to feed and yet only 1.4nmpg less while going 20kts faster. I take back my earlier comments about efficiency as I don't think my bird would go 20kts faster if I could put the 2.5 more gph through it. Got it. TAS is temperature dependent, of course and it was cold that day (for AZ). Quote
smccray Posted January 29, 2019 Report Posted January 29, 2019 1 hour ago, Shadrach said: No...I was going by the pic you posted with a TAS of 162 at 11.5gph LOP. So consider me amazed by the efficiency of your Bonanza. 23% more frontal area, 2 additional cylinders to feed and yet only 1.4nmpg less while going 20kts faster. I take back my earlier comments about efficiency as I don't think my bird would go 20kts faster if I could put the 2.5 more gph through it. This video is eye opening regarding "frontal area" as your constant. My interpretation is that the drag coefficient is far more important in assessing the efficiency rather than the frontal area. The frontal area makes a lot of sense in trying to market the efficiency of the plane, but the similar drag coefficients is far more relevant- see the last demo in the video comparing the frontal area of a wire versus the frontal area of an airfoil. It doesn't change that the Mooney is a more efficient airframe (assuming the drag coefficients in that article I linked are accurate), but the comparison is really much closer than it initially appears. 2 Quote
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