jetcareers - View Single Post - airplane riddle (taken from another board)

B767Driver · November 29th, 2005, 21:38

Maybe a good teacher out there can set me straight. I say it doesn't fly.

My rationale. The airplane has no forward movement...hence no relative wind and no airspeed. If I'm running on a treadmill...and I hold up a flag...the flag will drop straight down, dead. Hence, no relative wind acting on the flag. If I step off the treadmill and run holding the flag...it will blow in the breeze.

Let's say I'm a flying machine...built with a "strap on" set of wings that will allow me to fly once I reach 10 mph on the treadmill. I'll never fly...because I'll never produce a single knot of airflow over my wings because I'll always be at my starting point.

Much has been written about the wheels not being the propulsive source of the flying machine. However, on the ground, the wheels are the point of contact for the machine between the "mediums" it is operating in...the first being the ground...the second being the air. So until the machine becomes a flying machine...it is a ground machine.

As the conveyor negates the movement of the ground machine...it remains stationary...does not move...and does not produce an airspeed. Therefore no relative wind and no lifting force.

Can someone explain to me why the airplane will overcome the effects of the treadmill and advance it's position to produce an airspeed? If you can do that...I'll become a believer that it will fly.

Thanks.

November 29th, 2005, 21:38	#82
B767Driver Old Skool Join Date: Sep 2003 Posts: 1,888	Maybe a good teacher out there can set me straight. I say it doesn't fly. My rationale. The airplane has no forward movement...hence no relative wind and no airspeed. If I'm running on a treadmill...and I hold up a flag...the flag will drop straight down, dead. Hence, no relative wind acting on the flag. If I step off the treadmill and run holding the flag...it will blow in the breeze. Let's say I'm a flying machine...built with a "strap on" set of wings that will allow me to fly once I reach 10 mph on the treadmill. I'll never fly...because I'll never produce a single knot of airflow over my wings because I'll always be at my starting point. Much has been written about the wheels not being the propulsive source of the flying machine. However, on the ground, the wheels are the point of contact for the machine between the "mediums" it is operating in...the first being the ground...the second being the air. So until the machine becomes a flying machine...it is a ground machine. As the conveyor negates the movement of the ground machine...it remains stationary...does not move...and does not produce an airspeed. Therefore no relative wind and no lifting force. Can someone explain to me why the airplane will overcome the effects of the treadmill and advance it's position to produce an airspeed? If you can do that...I'll become a believer that it will fly. Thanks.