# Centripetal forces on a drifting Hangglider?

• GlenK
In summary: As the glider approaches the downwind leg of the turn, the pilot feels a stronger force pushing them away from the wind, due to the glider's greater speed. However, this force is actually the glider's increased altitude causing the air to behave more like a liquid.
GlenK
entripetal forces on a moving axis of rotation

OK Guys, we need some help to finish a debate over on our Hanggliding forum.
A question was raised, is there anyway of telling wind direction with NO visual reference (cant see the ground etc)
http://www.hanggliding.org/viewtopic.php?t=5451&postdays=0&postorder=asc&start=100
It was suggested that while circling you would be able to feel more force turning upwind to down wind ( I was guilty of believing this for a second)
Say you were circling in air that was moving over ground at the flying speed of the glider your in. At the point in the circle that you were facing headwind you would have a ground speed of 0 then as you continue the circle your ground speed would accelerate from 0 to double the gliders speed on the down wind portion of the circle, then you would decelerate back to 0 ground speed again as you went down wind to up wind.
But most have agreed this is wrong and the centripetal forces on a moving object(spining a weight on a string traveling in a car moving at a constant) is the same as while sitting still.
BUT we need the maths etc to show how a its still the same even while moving.
(assuming it is) PLEEEEEEEEEAZE help!

Last edited:
Sorry guys, I stuffed up the title on my last post, the title doesn't seem to change when i edit it and i don't seem to be able to delete it.. I fear no one will bother looking at it, so ill try again.
OK, we need some help to finish a debate over on our Hanggliding forum.
A question was raised, is there anyway of telling wind direction with NO visual reference (cant see the ground etc)
http://www.hanggliding.org/viewtopic.php?t=5451&postdays=0&postorder=asc&start=100
It was suggested that while circling you would be able to feel more force turning upwind to down wind ( I was guilty of believing this for a second)
Say you were circling in air that was moving over ground at the flying speed of the glider your in. At the point in the circle that you were facing headwind you would have a ground speed of 0 then as you continue the circle your ground speed would accelerate from 0 to double the gliders speed on the down wind portion of the circle, then you would decelerate back to 0 ground speed again as you went down wind to up wind.
But most have agreed this is wrong and the centripetal forces on a moving object(spining a weight on a string traveling in a car moving at a constant) is the same as while sitting still.
BUT we need the maths etc to show how a its still the same even while moving.
(assuming it is) PLEEEEEEEEEAZE help!

We have a 12 page argument on our forum yet not even 1 response from an expert here.
Im sure its probably so simple you can't be bothered, like trying to explain to someone that 2+2=4 , If they don't get it straight away they never will ?

No, way! Flying by the seat of your pants in IFR weather WILL get you killed, because your body is very BAD at detecting accelerations with no visual reference to aid it.

Also, an airplane does not know or care about ground speed. An airspeed indicator measures the relative wind to the pitot probe. You could have 100KTS headwind and stand still relative to the ground. The airspeed indicator would show you going 100KTS.

GlenK said:
But most have agreed this is wrong and the centripetal forces on a moving object(spining a weight on a string traveling in a car moving at a constant) is the same as while sitting still.
BUT we need the maths etc to show how a its still the same even while moving.
(assuming it is) PLEEEEEEEEEAZE help!

You won't need math to prove it. Ask them how the glider (or the pilot) knows ground speed from Adam. Ground speed is irrelevant.

If they can't see that, no math is going to convince them.

Aircraft fly relative to the air, not the ground, without the equivalent of a GPS system, there'd be no way to know the speed of the wind relative to the ground. For radio control gliders, there's a similar myth about the "downwind" turn.

## 1. What is a centripetal force?

A centripetal force is a force that acts towards the center of a circular motion and keeps an object moving along a curved path. In the case of a drifting hangglider, the centripetal force is responsible for keeping the hangglider in a circular path as it drifts through the air.

## 2. How does a centripetal force affect a drifting hangglider?

A centripetal force is essential for maintaining the motion of a drifting hangglider. Without it, the hangglider would continue moving in a straight line and not be able to turn or change direction. The centripetal force acts as a "pull" towards the center of the circular path, allowing the hangglider to maintain its curved trajectory.

## 3. What factors affect the strength of centripetal forces on a drifting hangglider?

The strength of the centripetal force on a drifting hangglider depends on three main factors: the speed of the hangglider, the mass of the hangglider, and the radius of the circular path it is following. The faster the hangglider is moving, the greater the centripetal force needed to keep it in a circular path. Similarly, a heavier hangglider or a smaller radius will require a stronger centripetal force.

## 4. Are there any dangers associated with centripetal forces on a drifting hangglider?

While centripetal forces are essential for maintaining the motion of a drifting hangglider, they can also pose a danger if they become too strong. If the hangglider is moving at a high speed or making sharp turns, the centripetal force can become too strong and cause the hangglider to lose control or even crash. It is crucial for hangglider pilots to understand and manage centripetal forces to ensure their safety.

## 5. Can centripetal forces be used to perform stunts or maneuvers on a drifting hangglider?

Yes, centripetal forces can be used to perform various stunts and maneuvers on a drifting hangglider. By manipulating the speed and angle of the hangglider, pilots can control the strength of the centripetal force and perform tricks such as loops, spins, and turns. However, it requires skill and practice to master these maneuvers safely.

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