Here's a totally hypothetical question that came up in a discussion with friends:

If a commercial aircraft (say, an Airbus A320) was "dropped" from a typical cruising altitude (say, 35,000ft) with a current ground speed of zero and all engines off, would it be possible to get it into gliding by putting the nose down, and how far could it go?

The much more practical question "how far can an aircraft glide" is already answered (e.g., How far can airplanes glide?), but it would be great if somebody could participate in this thought experiment with no engines and no initial speed.

  • 1
    $\begingroup$ With no power and no airspeed, you could not get the nose down. I don't think you will find an accurate answer since it's never been tested or modelled but my guess is that it would just continue to fall in a flat attitude until boom. $\endgroup$
    – Simon
    Aug 1 '15 at 9:12
  • $\begingroup$ You may search online under "balloon launched glider" as this the idea. This is done regularly, either RC aircraft, or actual aircraft. Note that a null ground speed does introduce the possibility of some relative airspeed, and even a large one, due to wind. When the glider is released with a null airspeed, gravity will accelerate it, initially at a 90° AoA, thus in a stalled condition. $\endgroup$
    – mins
    Aug 1 '15 at 10:08
  • 4
    $\begingroup$ @Simon: The cg of the aircraft is almost always ahead of the center of its projected area, so it will pitch down quickly. If it is naturally stable, it will then recover to a glide corresponding to its trim setting (given is has sufficient altitude). $\endgroup$ Aug 1 '15 at 10:34
  • $\begingroup$ In addition to what Peter Kaampf said about cg i would think that if dropping in a flat attitude the horizontal stabilizer would create significantly more drag at the rear, pitching the nose down. $\endgroup$
    – TomMcW
    Aug 1 '15 at 21:12

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