Mythbusters will finally test...

[photon]

Heh, I would say not pointless at all given the huge number of people who didn't understand the simple physics of it. I spent an hour explaining it to a guy at the office before he finally got it.

I think Mythbusters does a great public service. All those people who thought the plane wouldn't take off may or may not have learned something about physics.. but hopefully they did learn that to question their preconceptions and require evidence about them!



P.S. Kari is hot.

[Ryan Coke]

It took me a couple of pages of this thread to get what they were really trying to test, but once it became clear what they were doing it seemed a little dumb. As Ken said, it is just like testing to see if it could take off in a 30 kt tailwind. Of course it can, as long as the runway is long enough to get to the required airspeed.

The one thing I will add, is in the real world the other limiting thing (besides bearing friction or gear strength) is more realistically going to be wheel speed. Depending on the aircraft the tires are certified for a particular speed---for the 737 NG series it is max 225 kts, most transport category jet aircraft are between 225 and 235 kts. Basically fast enough for a flaps up landing, but not fast enough to take off on a gigantic treadmill going the wrong direction at more then 100 kts without coming apart.

[GreatWhiteEbola]

Originally Posted by ken0042

Pho- in the "control" test they had the plane take off @ 30 mph. Because there was no wind, the air speed and ground speed were the same. All they did to test the "myth" was start with a negative ground speed of the same 30 mph, and let the plane get up to a ground speed of 60 mph (relative to the treadmill); giving it the nessesary 30 mph needed to get enough lift to take off. So to answer the question, does the ground speed affect the ability for a plane to take off? No, of course not. I could have told you that.

The bottom line is a plane takes off when there's enough air speed to generate lift. Doesn't matter what the gound speed, wind speed, or anything else is. Once that plane hits an air speed of 30 mph it will take off.

Just seemed a little pointless to me.

I totally agree! The confusion comes with the interpretation not the concept being tested.