Plane on a treadmill .. to be on Mythbusters

[drkohler]

sieanr said:

drkohler said:

epsilon72 said:

drkohler, normal engines don't create airflow over a plane's wings by themselves. I don't think they're talking about building some strange new plane to do this.

Jetengines, no, but propellers actually do (which isn't the intention of a propeller) but they do as an added bonus. An actual experiment to check the myth will most likely fail anyways with any nornal plane geometry because the engine(s) cannot suck enough air to generate the power required.

 

Wrong on two counts

1. Props producing airflow over the wing is dependant on the position of the engine. In most cases the lift produced is relativly small - if you wanted anything big you'd need a ducted prop and carefully controlled airflow

2. Jets can also generate lift if placed slight ahead and on top of the wing. In fact, this is far more efficient than any extra lift props would produce and there have been several aircraft built this way.

Either way, claiming that you can take an aircraft off due to enough airflow from the engines alone is bogus. Not least of which is simply not enough airflow over the wings (ever), but also the complete lack of airflow over the "tail" of the aircraft.

We are not discussing whether you can walk to an airport and see a plane taking off...

Here is a short movie of a conventional propeller plane that 'almost does it'

http://www.alexisparkinn.com/photogallery/Videos/SuperCub18ftTO.mpg

Theoretically it should be possible to build  a much better propeller plane that actually does the trick..