# Questions tagged [glide-ratio]

The ratio of the forward distance traveled to the vertical distance an aircraft descends when gliding without any power.

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### How far can airplanes glide?

On an another question, an answer said: You don't need an engine to fly as airplanes are designed to glide without it. I suspect this heavily depends on the type of the aircraft, so lets assume we ...
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### Can we show through simple geometry rather than formulae or graphs that the best glide ratio occurs at the maximum ratio of Lift to Drag?

For an unpowered glider, can we show through simple geometry involving force vector diagrams, rather than mathematical formulae or graphs, that the best still-air glide ratio is achieved at the angle-...
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### Descending on a given glide slope (e.g. ILS) at a given airspeed-- is the size of the lift vector different in headwind versus tailwind?

We had a discussion with friend and we were talking about if the airplane is on approach and the one is landing with tailwind and the other one is landing with headwind, so both have the same value of ...
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### How are the glide polar and L/D ratio charts related?

We know from other questions and answers that airplanes and gliders in particular can have their performance described in terms of glide polar and Lift-to-Drag ratio. As it appears from the images in ...
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### Why is the L/D ratio numerically equal to the glide ratio?

*L/D is ratio of two forces, lift and drag. *Glide ratio is ratio of two distances. Can you explain mathematically how they end up numerically equal and are they always equal?
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### How does the Boeing 787 Dreamliner's glide ratio compare to other airliners?

I just saw a documentary on the design of the Boeing 787 "Dreamliner" and one of the designers said that the wings were inspired by gliders. Looking at the production version of the plane, it is ...
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### How to calculate the Glide Ratio from Drag & Lift?

I know that $c_{d}=0.03 + 0.095c_{l}^2$. What is the glide ratio?
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### What was the Space Shuttle's glide ratio?

The Space Shuttles glided to a landing in the atmosphere after reentry. They were not good gliders, aerodynamically speaking, so their glide slope angle was rather steep. What was the glide ratio of ...
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### Why don't smaller powered airplanes have better lift-to-drag ratios?

Many airliners have LDRs near 20, and it sounds like the electric Eviation Alice may have an LDR of 24 at 240 kts, but many small planes typically have LDRs of only 8-10. It seems like they could ...
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### Why are birdlike airfoils not used?

Here are two airfoils (lets focus on Re 100,000): SD7043-il which is simple to build and has a glide ratio of about 60 e376-il a birdlike and much harder to build if using paper or similar due to the ...
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### Do jet aircraft have a better glide ratio than propeller aircraft in general? If so, why?

Being fond of aviation, I play with software simulators a lot. I have noticed that while jets seem to be able to glide for a long distance even at zero throttle, propeller aircraft need to be ...
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### What would be the best alternative during a dead-stick approach?

(Disclaimer: I am not a pilot so my understanding of things may be really broken) If a plane has lost engine power, has limited altitude to work with, and is upwind of a landing strip, and the pilot ...
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### How can the glide ratio in a balanced turn be estimated?

I am trying to estimate the bank angle/turn radius required to lose a given amount of altitude during a full orbit. This has led me to trying to estimate glide ratio in proportion to $L/D_{MAX}$ of an ...
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### During an engine failure should I deploy 10° of flap or keep it clean?

Imagine I have an engine failure in cruise flight with a Cessna 152 or 172. Should I select 10° flap to increase glide angle? Would it give me more range to reach safety?
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### What is a mushing glide?

Source: Wolfgang Langewiesche - Stick and Rudder; An Explanation of the Art of Flying Why is it called a mushing glide? In this glide, does the aircraft point its nose less (or more?) steeply? How ...
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### What are "secondary precessional forces" that apply to boomerangs in flight?

note: This question is about the aerodynamics of boomerang flight and how it differs in microgravity environments. Some background information available here in Aviation SE: Are frisbees and ...
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### How useful would the space shuttle OMS actually be in atmosphere?

When speaking of space shuttle landings, they always mention that it is "very poor glider, with one shot, no go-arounds." Of course this is true; however, if the Shuttle found itself in a situation ...
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### Are frisbees and boomerangs technically gliders?

Frisbees and Boomerangs are heavier-than-air, unpowered, and fly through the air. So are they technically gliders? They also rotate, so I wonder if these are actually some kind of rotorcraft-type ...
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