SlumTodd_Millionaire
Most Hated Member
Did you just watch the frickin' show! This myth is busted, my friend. The airplane takes off. I can't believe any licensed pilot could actually argue with this. :banghead:
Poll: Mythbusters - Will the plane take off?
- Thread starter TheAlchemist
- Start date
Did you just watch the frickin' show! This myth is busted, my friend. The airplane takes off. I can't believe any licensed pilot could actually argue with this. :banghead:
I (a licensed pilot) initially thought "no" when I very first heard of this scenario.
BUT:
Once I separated cars' wheels from airplanes' wheels in my mind, and thought about how a plane flies, I realized my error.
darrenf
resident denizen
Airdale
Well-Known Member
I shall give you a pardon....but only once.
To be completely correct here, I should say that any licensed pilot who actually voted "no", had a very very very BAD instructor!!
aerospacepilot
New Member
I just read someone's response and I want to make a comment:
I thought the entire purpose of the airplane/treadmill scenario was to allow a plane to take off with almost no runway. The treadmill moves backwards at the aircrafts takeoff speed (say 60kts), so the airplane adds thrust that should accelerate it to 60 kts. Treadmill moves back at 60kts, airplane moves forward at 60kts (-60 + 60 = 0), so the airplane is not moving with regards to a fixed reference point on the ground. No air is flowing over the wings.
In that case, the airplane WILL NOT FLY! It cannot happen.
However, it sounds to me like you guys are saying the treadmill can move back at 60kts, and the airplane would need to add thrust equivalent to accelerating to 120kts. Therefore, relative to a fixed point on the ground, the airplane would be moving at 60kts. Therefore 60kts of air would be flowing over the wing, and of course the airplane WILL FLY!
But that begs the question... What the heck is the point of this???????????????????????????????
I thought the entire purpose of the airplane/treadmill scenario was to allow a plane to take off with almost no runway. The treadmill moves backwards at the aircrafts takeoff speed (say 60kts), so the airplane adds thrust that should accelerate it to 60 kts. Treadmill moves back at 60kts, airplane moves forward at 60kts (-60 + 60 = 0), so the airplane is not moving with regards to a fixed reference point on the ground. No air is flowing over the wings.
In that case, the airplane WILL NOT FLY! It cannot happen.
However, it sounds to me like you guys are saying the treadmill can move back at 60kts, and the airplane would need to add thrust equivalent to accelerating to 120kts. Therefore, relative to a fixed point on the ground, the airplane would be moving at 60kts. Therefore 60kts of air would be flowing over the wing, and of course the airplane WILL FLY!
But that begs the question... What the heck is the point of this???????????????????????????????
caliginousface
Frank N. Beans
The treadmill can be moving backwards at 200kts, or 300kts, or more...the biz will fly.
darrenf
resident denizen
aerospacepilot
New Member
I know, but relative to a fixed point on the ground, the airplane would still have to be moving forward at 60kts.
Again, then what is the point of this entire scenario? Why not just use a normal runway. It will cover the same distance, take off at the same relative speed....
SlumTodd_Millionaire
Most Hated Member
Aerospacepilot, you still don't seem to understand. The airplane doesn't have to add thrust to accelerate to 120 knots. It only has to add thrust to accelerate to 60 knots. The reverse speed of the treadmill is irrelevant, because the wheels are not imparting the force the accelerate the airplane; the propeller is. The wheels just freely spin, no matter what the speed of the treadmill is. You could accelerate the treadmill to -150 and a Cessna with a rotation speed of 55 knots would still be able to accelerate and takeoff.
Clocks
Well-Known Member
Will you please stop typing that?
ITS NOT TRUE.
The treadmill moving backwards at 60kts + airplane moving forward at 60kts = THE AIRPLANE MOVING FORWARD AT 60kts. The wheels might be spinning faster, but the airplane is moving forward with regards to a fixed reference point on the ground as if the treadmill wasn't even there.
The "goal" of this myth is for to create a vertical-takeoff cessna. It's to point out the difference between a car on a treadmill and a plane on a treadmill.
aerospacepilot
New Member
I understand. But lets say you were standing on non-moving ground right next to the treadmill. How fast does the airplane appear to be moving RELATIVE TO YOU (standing still). If it is 55kts, then this scenario is stupid. It has no purpose.
Am I correct?
Berkut
Well-Known Member
It was just hypothetical. No one was saying that an aircraft on a treadmill actually provided any benefit. I replied to you back on page one and said:
Berkut said:
WildcatPilot
Well-Known Member
"pilot mark" doesn't know what he's talking about
"I'm just going to sit there like a brick"--- Pilot Mark
OK Amber.. LOCK IT!!
Okay, I'm one week out of surgery here, must you make me laugh like that EVERY DAMN NIGHT! I'm going to run out of painkillers!
Where the heck did they find that guy?
darrenf
resident denizen
The fact that any PILOTS voted no, I find interesting.