# What was the lift-to-drag ratio for WWI biplanes?

I will be interested to know what was the lift-to-drag ration for a few more known WWI biplanes at take-off, cruise and landing speed; with the propeller running, stopped or non existent (tests in wind tunnels).

• It'll be tough to find that unless you rummage around university study archives or find some old NACA reports. It's easy to give a ballpark figure. Reasonably clean monoplanes are generally 8:1 to 11:1. A flying barbwire fence like a WW1 biplane would range from 4:1 to 7:1. Commented Oct 13, 2020 at 15:32
• @JohnK I'm looking at Wikipedia. Maybe I could infer the value from the specs? Commented Oct 13, 2020 at 15:35
• I don't think you could. You would have to be able to work out the glide angle at different speeds, and so you'd have to have the sink rate at a given speed. Commented Oct 13, 2020 at 15:44
• @JohnK well, what i was trying to do was get the thrust/weight then reciprocal. You know, get a lower bound value? Commented Oct 13, 2020 at 16:03