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### Why would a glider have water ballast? If it is trying to stay aloft without an engine, wouldn't it be better to be as light as possible?

So I was looking at the description of a ASW 27 B glider and ran across this statement: Two water tanks in the wing plus a further 35 liter tank in the fuselage enable the ASW 27 B to carry more ...
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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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### What is the difference between the Maximum Glide and Minimum Sink ratios?

In this comment a brief explanation is made of the differences between Max Glide Ratio and Min Sink Ratio: Sink rate is how much altitude you lose over time, for example, how many feet per second. ...
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### What determines the best glide speed?

I found the best glide speed of cessna 152 is 60 kts. My question is why it is not more or less than 60 kts? What are the factors upon which the best gliding speed is determined?
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### How does lowering altitude conserve energy in Solar Impulse 2?

In this article the author explains that the aircraft flies at a lower altitude to conserve energy. During the day, it climbs to its maximum cruising altitude of 8,500 metres to capture the most ...
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### Why do Vx and Vy coalesce at an airplane's absolute ceiling?

I'm struggling to figure out why that is the case. I'm trying to determine why the best angle of climb speed equals to best rate of climb speed at the absolute ceiling on airplanes.
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### Can weight reduce a plane's glide ratio?

The FAA says glide ratio doesn't change, regardless of weight, here on page 5-7. Glide ratio is not affected by weight because, while a heavier glider sinks faster, it does so at a greater airspeed. ...
605 views

### Matching the Drag Equation to Real Airplane Data

I am trying to compute airplane performance for a piston-driven airplane with constant speed prop using the standard equations for Lift, Thrust and Drag. I have found that there are a couple of useful ...
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1 vote
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### How can I properly model paper airplane physics? [closed]

I am working on a game involving flying and steering a paper airplane for WP7. I want the plane to fly just like how normal paper airplanes (online game) but I can't seem to find an equation for how ...
1 vote
560 views

### 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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