Balloon Elevation: Will Wind Affect Their Flight Time?

[corvette]

If you have 2 balloons made out of the same material, filled with the same type and quantity of gas, caring the exact same pay load. They are both in the same temperature and humidity air. You let them both go at the exact same time. 1 being acted on by prevailing winds that change speed and direction, and the other having no wind of any kind acting on it.

Would they both reach 40,000 ft at the exact same time? Why or why not?

 

[berkeman]

If you have 2 balloons made out of the same material, filled with the same type and quantity of gas, caring the exact same pay load. They are both in the same temperature and humidity air. You let them both go at the exact same time. 1 being acted on by prevailing winds that change speed and direction, and the other having no wind of any kind acting on it.

Would they both reach 40,000 ft at the exact same time? Why or why not?

What do you think will happen?

 

[corvette]

I think they will both reach the same altitude at the same time because gravity is a constant and the amount of lift is a constant.Those are the only 2 things working on the balloons.

I am in a discussion with my wife about this. She believes that the time going down range is affecting the rate of assent. Thus the balloon rising with the effects of wind will reach 40,000 ft after the balloon rising with no wind effecting it.

 

[berkeman]

I think they will both reach the same altitude at the same time because gravity is a constant and the amount of lift is a constant.Those are the only 2 things working on the balloons.

I am in a discussion with my wife about this. She believes that the time going down range is affecting the rate of assent. Thus the balloon rising with the effects of wind will reach 40,000 ft after the balloon rising with no wind effecting it.

I'm no expert in aerodynamics, but my guess would be that the air turbulence created by the sideways wind will affect the "lift" of the balloon, and thus its time to 40,000 feet. But I don't know if it would add to the vertical drag of the balloon, or if it depends on the shape of the balloon how the sideways wind affects the vertical drag... My guess is that it would slow its ascent down, but that's just an intuitive guess.

 

[LostConjugate]

I would guess that the wind would allow the balloon to travel up faster. Because of the balloon's shape in a gravitational field.

The top of of the balloon is less of a slope than the bottom of the balloon. So the air traveling over the top would travel faster and there would be less pressure above the balloon than below.

I can say for certain that the time going "down range" is not effecting the balloon's accent.

 

[davenn]

Thinking about this...

wouldn't the trip downrange be a longer path to the 40,000ft height than the direct vertical path, therefore a longer time traveled ?

think of a vertical line of a flat lying rectangle Vs the much longer diagonal line

Dave

 

[berkeman]

Thinking about this...

wouldn't the trip downrange be a longer path to the 40,000ft height than the direct vertical path, therefore a longer time traveled ?

think of a vertical line of a flat lying rectangle Vs the much longer diagonal line

Dave

No. The point is if the vertical velocities are the same, the horizontal motion makes no difference. Kind of analogous to how a dropped bulled and a horizontally-fired bullet hit the ground at the same time.

 

[davenn]

ok thanks :) had me pondering tho ;)

cheers
Dave
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