[ELI5] how do hot air balloons even work? How do they know where they’re going without steering?
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They don’t know where they’re going.
You check weather reports about the prevailing wind direction, and hope it doesn’t suddenly change. Or you test out different elevations and see which way the air is moving.
They don’t know where they’re going.
You check weather reports about the prevailing wind direction, and hope it doesn’t suddenly change. Or you test out different elevations and see which way the air is moving.
A hot air balloon is a lighter-than-air craft, in the same category as blimps. They fly differently than aircraft with wings or gliding objects like planes and helicopters do. The physical principle here is that if the air inside the object is less dense than the air outside, it will float in the air. This is the same reason why helium balloons will float if you let go of them – helium as a gas is less dense than the air. In the case of a hot air balloon, it’s the heat of the air that contributes to the density.
Hot air balloon pilots will adjust the heat inside the balloon to either go up or down in the air. They can’t control direction very well, which is why they’re generally not used to get from point A to point B. They run into problems if it suddenly gets too windy or rainy. That’s why hot air balloons would be ideal in desert climates such as New Mexico or Arizona where it is probably not going to rain and it doesn’t get super windy.
The short answer is that they have no direct control of where they’re going. The long answer is that with special instrumentation and knowledge of weather patterns, they can generally get around by changing their altitude. Like for example if you know that there’s a wind blowing east at around 100m of altitude and you want to go east, you go up to 100m. This means that accurate weather predictions and real time weather information is crucial for a flight. Flights can be planned according to weather forecasts and cancelled if the expected weather is not right.
Generally speaking due to the coriolis effect, which is the apparent movement over the earth combined with the spin of the Earth, it’s possible to “steer” the balloon somewhat by going high enough where the wind is more consistent and basically turn east due to this effect, which is a combination of the wind direction and the earth moving out from under you. If you have a rudimentary ability to steer, up in the air it’s enough since you can make a right turn or make “three right turns” until you’re pointing left.
The short answer is that they have no direct control of where they’re going. The long answer is that with special instrumentation and knowledge of weather patterns, they can generally get around by changing their altitude. Like for example if you know that there’s a wind blowing east at around 100m of altitude and you want to go east, you go up to 100m. This means that accurate weather predictions and real time weather information is crucial for a flight. Flights can be planned according to weather forecasts and cancelled if the expected weather is not right.
Generally speaking due to the coriolis effect, which is the apparent movement over the earth combined with the spin of the Earth, it’s possible to “steer” the balloon somewhat by going high enough where the wind is more consistent and basically turn east due to this effect, which is a combination of the wind direction and the earth moving out from under you. If you have a rudimentary ability to steer, up in the air it’s enough since you can make a right turn or make “three right turns” until you’re pointing left.
A hot air balloon is a lighter-than-air craft, in the same category as blimps. They fly differently than aircraft with wings or gliding objects like planes and helicopters do. The physical principle here is that if the air inside the object is less dense than the air outside, it will float in the air. This is the same reason why helium balloons will float if you let go of them – helium as a gas is less dense than the air. In the case of a hot air balloon, it’s the heat of the air that contributes to the density.
Hot air balloon pilots will adjust the heat inside the balloon to either go up or down in the air. They can’t control direction very well, which is why they’re generally not used to get from point A to point B. They run into problems if it suddenly gets too windy or rainy. That’s why hot air balloons would be ideal in desert climates such as New Mexico or Arizona where it is probably not going to rain and it doesn’t get super windy.
A couple things
-Hot air balloon pilots are actual licensed pilots. There’s quite a bit of training and certification to earn and maintain these quals.
-Sticking to take-off locations where the weather patterns are consistent
-real-time weather analysis in the wind column. There are actual apps available that tell you real time info of the weather at altitude. With this knowledge, one can calculate approximations based on probabilities and steer in the weather column as others have elluded to.
It’s really a combination of knowing (or guessing) which way the wind is blowing at different altitudes (because you can control up and down), and not caring a great deal about exactly where you end up. You’re not going to land at an airport, you’re going to land at a field in northwest Ohio. Not even a particular field sometimes, just any field. Ideally one far away from power lines. And you’ll end up paying a farmer for damaged crops sometimes if you can’t find an empty field.
And sometimes you misread the weather really badly and end up on the evening news.
It’s really a combination of knowing (or guessing) which way the wind is blowing at different altitudes (because you can control up and down), and not caring a great deal about exactly where you end up. You’re not going to land at an airport, you’re going to land at a field in northwest Ohio. Not even a particular field sometimes, just any field. Ideally one far away from power lines. And you’ll end up paying a farmer for damaged crops sometimes if you can’t find an empty field.
And sometimes you misread the weather really badly and end up on the evening news.
A couple things
-Hot air balloon pilots are actual licensed pilots. There’s quite a bit of training and certification to earn and maintain these quals.
-Sticking to take-off locations where the weather patterns are consistent
-real-time weather analysis in the wind column. There are actual apps available that tell you real time info of the weather at altitude. With this knowledge, one can calculate approximations based on probabilities and steer in the weather column as others have elluded to.
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