That airplane on a treadmill thing, was there a correct answer?

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Classic, depends on which speed the treadmill is matching, if it is the planes forward speed then the plane takes off, if it is the rotational speed of the wheels then it doesn't.
 

TVC

Guest
Classic, depends on which speed the treadmill is matching, if it is the planes forward speed then the plane takes off, if it is the rotational speed of the wheels then it doesn't.

The tread mill makes no difference, the thrust is against the air mass generating forward acceleration. If the drive were through the wheels like in a car then things would be different.


Oh Bugger, I think I might just have got involved.
 

Archie_tect

De Skieven Architek... aka Penfold + Horace
Location
Northumberland
If the thrust of the air from the propellers over the wings is sufficient to create enough lift the plane will take off. Before this lift is created the plane's acceleration will project it forward... if the treadmill doesn't match this forward acceleration exactly the plane will travel forwards and fall off the front of the treadmil before it leaves the ground.
 
It was a theoretical plane on a theoretical treadmill. The forum the question was asked on is also now theoretical as it no longer exists. If I remember correctly any theoretical answers were prevented when the theoretical electricity supply to the theoretical treadmill ran out due to not enough theoretical pound coins to feed the theoretical meter. In theory.

If anyone tries to revive the boxer vs mixed martial artist thread I'll be getting my coat.
 

Archie_tect

De Skieven Architek... aka Penfold + Horace
Location
Northumberland
It was a theoretical plane on a theoretical treadmill. The forum the question was asked on is also now theoretical as it no longer exists. If I remember correctly any theoretical answers were prevented when the theoretical electricity supply to the theoretical treadmill ran out due to not enough theoretical pound coins to feed the theoretical meter. In theory.

If anyone tries to revive the boxer vs mixed martial artist thread I'll be getting my coat.

Chicken/ Egg? You decide, I'm following Ghost Donkey to the Pub.....
 

benb

Evidence based cyclist
Location
Epsom
It's odd that people are arguing about this.
Facts:
  1. An aeroplane must get enough airflow over the wings to generate lift for takeoff. No airflow = no takeoff
  2. An aeroplane does this my moving forwards at some speed (+ or - whatever the wind is doing)
  3. An aeroplane generates thrust with its engines to move it forwards
  4. The thrust is not generated through the wheels, but from the wings
  5. The wheels of an aeroplane are basically free to rotate, ignoring the brakes for a moment
  6. It is impossible for the treadmill to slow the aeroplane down, because the forward thrust is not delivered through the wheels
So, you can spin the treadmill as much as you like - it will not stop the plane from moving, as the engines "push" against the air (OK, Newton's 3rd law, but you get the point) and not the ground. If the plane is travelling at 50mph forwards, and the treadmill is rotating at 50mph backwards, that just means the wheels are spinning at 100mph. Because there is no link between the thrust and the wheels - the wheels are just there to reduce friction between the fuselage and the ground - it is impossible for the treadmill to slow the plane down.

Any questions?
 

Fnaar

Smutmaster General
Location
Thumberland
What if someone put the plane the wrong way round on the treadmill at the start of the experiment? It would simply fall off the end!
wacko.gif
 

Shaun

Founder
Moderator
Whatever you do, don't mention the one about the two cars hitting each other head on at 50mph .... ;)
 
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