# Calculating Balloon Range and Altitude

• KJ4EPE
In summary, the conversation discusses a thought experiment on a hypothetical vacuum airship and the determination of quantities such as volume, mass, net force, and acceleration. The individual is seeking guidance on how to calculate the range and altitude using these quantities, and later realizes the need to factor in pressure and density changes. The conversation also mentions the limitations of using a predetermined envelope for the airship's maximum altitude.

#### KJ4EPE

I feel kinda stupid asking this, since I have a bachelor's degree in physics. But, here it goes: I'm doing a thought experiment on my own (i.e., not a homework problem) for a hypothetical vacuum airship. I've determined the following quantities:

V_displaced = 15 m^3
m = 13.5 kg
F_net = F_buoyancy - Weight = 44.0 N upwards
a = 3.26 m/s^2 upwards
I'm assuming that winds are calm (i.e. v_wind = 0), and I've not factored in how pressure and density change over altitude.

Again, I feel like a dunderhead for asking this, but using these quantities, how can I calculate range and altitude? All the equations I know involve the use of initial velocity, but the only forces acting on the airship are gravity and the buoyant force.

Okay, I thought about it some more, and I realized: I will need to factor in the change of pressure and density, because the maximum altitude is when the buoyant force is equal to the weight. Duh. Now I'm off to figure that out.

Are you still working on this? Remember that for a conventional "weather balloon", the material is latex which will allow the lifting gas to expand and expand until the balloon bursts. If you have a determined enevelope which won't expand over a predetermined volume, that's going to be your max altitude...I think...

## 1. How do you calculate the range of a balloon?

The range of a balloon can be calculated by using the balloon's ascent rate, descent rate, and the time it spends in the air. The formula for calculating range is: Range = (Ascent Rate + Descent Rate) x Time in Air. This will give you the total distance the balloon travels during its flight.

## 2. What factors affect the altitude of a balloon?

The altitude of a balloon is affected by several factors, including the amount of gas or helium in the balloon, the weight of the payload, and the temperature and pressure of the surrounding air. Wind speed and direction can also impact the altitude of a balloon.

## 3. How do you calculate the altitude of a balloon?

The altitude of a balloon can be calculated by using the balloon's ascent rate, descent rate, and the time it spends in the air. The formula for calculating altitude is: Altitude = (Ascent Rate x Time in Air) - (Descent Rate x Time in Air). This will give you the maximum height the balloon reaches during its flight.

## 4. How do you account for wind when calculating the range and altitude of a balloon?

To account for wind when calculating the range and altitude of a balloon, you can use a weather forecast to determine the wind speed and direction at different altitudes. This information can then be factored into the calculations for range and altitude. Additionally, some balloon tracking software can also take into account wind data to provide more accurate results.

## 5. Can you predict the range and altitude of a balloon before its flight?

Yes, it is possible to predict the range and altitude of a balloon before its flight by using the balloon's specifications, such as gas volume, payload weight, and ascent and descent rates. However, factors such as wind and changing weather conditions can impact the actual range and altitude achieved during the flight, so these predictions may not always be completely accurate.