on a wing and a prayer

[Mark]

On the summer of 1983, an Israeli F-15 staged a mock dogfight with
Skyhawks for training purposes, near Nahal Tzin in the Negev desert.
During the exercise, one of the Skyhawks miscalculated and collided
forcefully with the F-15's wing root. The F-15's pilot was aware that
the wing had been seriously damaged, but decided to try and land in a
nearby airbase, not knowing the extent of his wing damage. It was only
after he had landed, when he climbed out of the cockpit and looked
backward, that the pilot realized what had happened: the wing had been
completely torn off the plane, and he had landed the plane with only
one wing attached. A few months later, the damaged F-15 had been given
a new wing, and returned to operational duty in the squadron. The
engineers at McDonnell Douglas had a hard time believing the story of
the one-winged landing: as far as their planning models were
concerned, this was an impossibility.

source-Wikipedia
subject-lifting bodies

Mark

[Bob Kuykendall]

On Dec 28, 2:57*pm, Mark > wrote:
> The engineers at McDonnell Douglas had a hard time
> believing the story of the one-winged landing...

The Wiki article on the F-15 explains it, with references:

http://en.wikipedia.org/wiki/F-15_Eagle#Notable_accidents_and_incidents

An engineer I met at ESA Tehachapi a few years ago not only wasn't
surprised about it, he worked the rhoV^2 as part of his presentation
on adaptive control.

[Morgans[_2_]]

"Mark" > wrote

> The F-15's pilot was aware that
> the wing had been seriously damaged, but decided to try and land in a
> nearby airbase, not knowing the extent of his wing damage. It

> engineers at McDonnell Douglas had a hard time believing the story of
> the one-winged landing: as far as their planning models were
> concerned, this was an impossibility.

> source-Wikipedia
> subject-lifting bodies

The ability to stay in the air depends on enough lift being produced, then
on the ability to balance it to stay in a consistent, controlled attitude.

Producing lift, no problem. It still had one wing, and a fairly good
lifting body, so if you go fast enough, you can make enough lift. The lift
was totally off axis, and not symmetrical, and there is where a special
characteristic (not planned on being used in this manner) of the aircraft
came into play.

The totally independent full flying tail surfaces are what did the trick.
Let's say you remove the right wing. If you put the leading edge of the
right tail surface up, you will have the left wing and the right tail making
lift. If you can balance the aircraft on those two surfaces, you win. They
did.

If you make the left tail's leading edge go down, you will provide negative
lift, which can be used to lift up the weight of the aircraft that is ahead
of the line formed by the left wing and the right tail, which are the two
surfaces that we are balancing the aircraft on. Use all three of the flying
surfaces you have left, and keep going fast enough, and you get to keep the
aircraft. Pretty amazing, until you think about it, then it is very
amazing! <g>
--
Jim in NC