Best Glide Speed

[sabwjz]

I've been trying to determine best glide speed on my recently purchased '68 G.  I've gone through the owner's manual cover to cover but I don't see it listed anywhere.  Does anyone have any idea?  Also what is the glide ratio of this same aircraft.

[GeorgePerry]

Best glide occurs at L/D max.  Which is usually very close if not exactly the same as Vy.  Exact speed varies based on gross wt, (heavier = alittle faster) but if you're within a few knots of Vy your pretty close.  Goolge search L/D max or best glide to get the detailed explanation of the science

[Seth]

For a 1967 F (same body as the G except for the air intake filter in the cowl) my speeds are 100 and 104, depending on if the prop is stopped vs. windmilling, both are in MPH

[The-sky-captain]

My POH has a chart depicting the best glide speed under the "Emergency Procedures" tab. It works out to be about two miles for every 1000' agl you are. Speeds are pretty close to what has been mentioned above.

[eaglebkh]

107mph in my E

[N207LS]

I also was taught to use 100 mph, as it is easy to remember if ever needed in an emergency... 

[FlyDave]

There are actually 2 different glide speeds used in aircraft.

"Best L/D" will give you the greatest distace travelled vs. time and the other, "minimum sink" will give you greatest time aloft. Usually, greatest distance/time is what is listed in a power plane's POH as you want to try to reach your intended/attempted" landing spot in an engine out or other emergency. But minimum sink could come in handy as well if you're still trying to find that best landing spot.

In sailplanes, we try to fly closer to minimum sink when thermalling and best l/d when flying inter-thermal. Just another perspective.

[FlyDave]

Quote: JimR

Very interesting perspective and valid point, Dave. Thanks. Intuitively I would assume that minimum sink is typically the slower of the two speeds. Is that correct?

[Guest Anonymous]

Quote: N207LS

I also was taught to use 100 mph, as it is easy to remember if ever needed in an emergency...