Ed - I never use the term "best glide speed" because it doesn't define what is best.
Do you want the best forward progress for each unit of altitude lost, or do you want the best (least) sink rate? So, I use either Minimum Sink Speed, to describe just that; or Best L/D, which is best lift over drag, to describe the speed that produces the farthest forward progress per unit of lost altitude. Don't mean to be hyper-technical, just trying to make these terms clear. Jerry E. -----Original Message----- From: [email protected] [mailto:[email protected]]on Behalf Of Ed Burkhead Sent: Tuesday, December 29, 2009 4:45 PM To: 'Techlist Ercoupe' Subject: SPAM-LOW: RE: [ercoupe-tech] Glide Ratio Hartmut wrote: > One way to find out your sink rate is to fly your Coupe > with an VSI and read the numbers at certain airspeeds. > I found That 65 to 70 gives you the least sink rate. 70 to > 75 might give you more distance without much penalty > to the sink rate. > If you find yourself having the best glide at 80 to 85, > check your static system. The VSI is also good for finding maximum endurance airspeed as that is close to the minimum sink airspeed. For figuring the best glide speed, you need to take into account forward progress (true air speed). That's exactly what a glide ration is, forward motion compared to vertical motion. With my faulty ASI, the best glide ratio airspeed was at 85 indicated on that faulty indicator. I think that the ASI is at fault more often than the static system but either could be the cause of errors. For my plane, a new ASI brought the numbers back exactly (less than half a mph) to what exact calibration shows was correct. Ed
