How to inflate a
weather balloon?

Stratoflights:
We answer to all
of your questions!


Where do I get helium or balloon gas for my weather balloon?

How to inflate a weather balloon with the correct amount of helium?

How to calculate the flight path of a weather balloon?



In order to launch your own mission to the edge of space with your weather balloon, you need to fill your weather balloon with helium or balloon gas. But where do you get helium or balloon gas for weather balloons and how much helium is needed at all? How to calculate the correct amount of helium? How do I fill the right amount of helium into the weather balloon and how do I seal the weather balloon and can you predict the flight path? Stratoflights provides you with all the answers to your questions for a successful mission to the edge of space!

Where do I get helium
or balloon gas?


In order for your weather balloon to rise and develop lift, your weather balloon must be filled with a gas that is lighter, or has a lower density than oxygen. Helium has a lower density than oxygen and therefore develops buoyancy and is not flammable, unlike hydrogen, which is even lighter. Helium is available in different purities, which also affects the price. Therefore we recommend to use balloon gas. This usually consists of 95% helium and other gases such as oxygen, etc.. Balloon gas is perfectly sufficient for your mission to the edge of space.

Helium or balloon gas is usually available at the gas dealer in your region. Just Google for gas dealers in your area and ask directly via mail or phone. What many people do not know: Balloon gas is often also available in larger hardware stores and we don't mean the small canisters of balloon gas for party balloons! So ask also at larger hardware stores if they have balloon gas or helium in stock.

How to calculate the amount
of helium for my weather balloon?


The helium calculator from Stratoflights calculates exactly how much helium or balloon gas you need for your weather balloon at your payload and ascent speed and displays the result in liters and also in pressure, in the unit bar.

So if you can answer the three questions, which weather balloon you want to use at which altitude, how heavy your payload is and how big your ascent speed is, then you can use the helium calculator for an exact calculation and get the result in liters of helium or bar.

helium calculator weather balloon

An important information you can give the helium calculator, but don't have to, is the bottle size: If you already have a bottle of helium from your gas dealer, for example, these are available in 5, 10, 20, 30 and 50 liters volume with 200 bar filling pressure, then the helium calculator can also take this into account and shows you next to the number of liters you have to fill into your weather balloon also the amount of bar you have to fill into your weather balloon. If you don't have a bottle size yet, that's no problem! Then just use the result in liters of helium.

How to inflate a weather balloon
with the correct amount of helium?


To begin with, there is no more accurate way to fill your weather balloon with helium than the following:

You have now used the helium calculator to determine how much helium or balloon gas you need to fill into your weather balloon. You also now have your bottle of helium or balloon gas from the gas dealer and know the bottle size. Usually these are 5, 10, 20, 30 or 50 liter bottles with a pressure of 200 bar.

Additional info: This means that a bottle with a compressed volume of 5 liters of bottle volume and a filling pressure of 200 bar has a content of 5 x 200, which is therefore 1,000 liters of helium or balloon gas! With a 20 liter bottle and a filling pressure of 200 bar, this is a content of 20 x 200 = 4,000 liters of helium or balloon gas.


The helium calculator has given you the amount of helium or balloon gas you need for your weather balloon in bar filling pressure and in liters. Now screw the bottle pressure reducer to your gas bottle. After you have opened the valve on your gas bottle, the bottle pressure reducer shows the pressure in your gas bottle. Using the hose on the pressure reducer, you can now fill your weather balloon with the amount of helium that was given to you in bar by the helium calculator.

bottle pressure reducer

The following example shows that you have to fill a total of 3441 liters of helium or 191 bar into your weather balloon 1600 and a payload of 850 grams with a bottle size of 20 liters. The 20 liter bottle has a filling pressure of 200 bar. With the bottle pressure reducer, you can now let as much helium flow through the hose into your weather balloon 1600 until there is only 9 bar filling pressure left in your helium bottle. This means that 191 bar or 3.441 liters of helium are now in your weather balloon. You cannot fill your weather balloon with helium more accurately!

How to connect the cylinder pressure reducer to the gas cylinder and how to fill and seal your weather balloon, you can find more information and videos here.

How to calculate the
flight path of a weather balloon?


You want to know exactly where your probe will land the next day? No problem! Use the Stratoflights flight path prediction tool and calculate your landing site to an accuracy of 5-10 kilometers the day before the launch of your weather balloon. This way you can drive directly after the launch of your weather balloon to the landing region and wait for the exact coordinates of the landing, which will be transmitted by the GPS Tracker STRATOfinder.

Our tool takes into account the current weather conditions by the launches of the weather balloons of the respective weather services in your region, so an accurate forecast is possible. To predict the flight path of your weather balloon, you only need to enter a few simple details. In addition to the tool, as with all our tools, we also provide an explanatory video with some tips and tricks for a successful mission.

flight path prediction tool

FAQ: You have the questions,
we have the answers.


What does a weather balloon cost?

The price of a weather balloon depends on your goal: How high do you want your weather balloon to fly and or how much payload do you want the weather balloon to carry? Weather balloons are available in different sizes and thus costs vary. Prices for all models of our high quality meteorological balloons can be found in our shop.

What is the delivery time of weather balloons?

We hand over all orders to DHL or DHL Express from our warehouse in Germany on the next business day. The exact delivery time depends on whether the delivery is to be made within or outside the EU. One thing is clear: With our logistics partners DHL and DHL Express we enable a maximum of delivery speed. Faster is not possible.

Why does a weather balloon burst?

Weather balloons can reach altitudes of up to 40,000 meters (131,233 ft). That's three times higher than commercial aircraft fly. As altitude increases, the ambient atmospheric pressure decreases. The further we move away from sea level in altitude, where the atmospheric pressure is exactly 1 bar or 1,000 hPa, the air pressure decreases noticeably. When climbing mountains, for example, breathing becomes difficult quite quickly. At an altitude of just under 5 kilometers (3.1 mi) (16,404 ft), the atmospheric air pressure has already halved. The helium or balloon gas, which provides buoyancy for the weather balloon, expands as the atmospheric pressure continues to decrease, and so does the weather balloon. Thus, weather balloons can become up to 15 meters in diameter due to their elastic natural rubber-latex mixture, before you then burst at minimum air pressure.

What is a weather balloon filled with?

In most cases, weather balloons are filled with helium or the less expensive balloon gas, which consists of about 95% helium. Weather services and research facilities occasionally also use hydrogen, as this has an even lower density and allows for even more buoyancy.

How to fill a weather balloon?

To fill a weather balloon with helium/ balloon gas, you need helium/ balloon gas, which is available in gas bottles. To fill the helium/ balloon gas from the bottles in the previously calculated amount with the Helium Calculator into the weather balloon, a Pressure Reducer is needed. With this you can fill the exact calculated amount from the gas bottles via the hose of the Pressure Reducer into the weather balloon.

What is a weather balloon made of?

A weather balloon or meteorological weather balloon consists, among other things, of a natural rubber-latex mixture, so that the weather balloon can expand to many times its volume with increasing altitude.

Are you allowed to launch a weather balloon?

You are allowed to launch a weather balloon if you have obtained the required ascent permit in your country for the ascent and if you have obtained the ascent permit for the operation of your weather balloon and if you meet the required conditions, if any. Thus, a weather balloon may be launched by anyone, whether a research institution, business, school or private individual. Here you can find a listing of aviation authorities of different countries.

Where does a weather balloon launch have to be registered?

In most cases, the ascent of weather balloons is applied for at the respective aviation authorities or traffic authorities of the respective country. We have compiled a few countries and their aviation authorities here.

Is it allowed to launch a weather balloon as a private person?

Yes, as long as you apply for the ascent permit in your country and comply with any conditions required for the ascent, so basically anyone may launch a weather balloon, whether a private person, school, company or research institution, who has obtained the required ascent permit.

Can you print on weather balloons? Is it possible to print a logo on weather balloons?

In order to print a logo on the sensitive and very thin layer of the weather balloon, the already very thin surface must be roughened so that the color of the logo adheres to the weather balloon. The roughening creates a predetermined breaking point, since the weather balloon expands due to the ever decreasing ambient pressure during the ascent and will burst at the printed area already at a very low altitude. In this respect, printing the weather balloon is not possible or sensible.

Is there a difference between weather balloon, meteorological weather balloon, high altitude balloon (HAB), sounding balloon and stratospheric balloon?

No. Since weather balloons usually fly in the so-called stratosphere, this atmospheric layer starts from 15 kilometers altitude (9.3 mi) (49,212 ft), weather balloons are also sometimes called stratospheric balloons, meteorological weather balloons, meteorological balloons, high altitude balloons and sounding balloons.

What are weather balloons and meteorological weather balloons used for?

Weather balloons, stratospheric balloons, high altitude balloons (HAB), sounding balloons or also known as meteorological weather balloons, have numerous applications: Weather balloons are mainly used by weather services, universities for atmospheric altitude research and weather forecasting. Furthermore, weather balloons are used by schools for school projects to launch small cameras and measuring instruments as part of school project weeks. Private individuals use weather balloons, for example, to make their own video recordings from the edge of space. Weather balloons are also used near the ground to lift amateur radio payloads such as weather probes and to transmit via APRS. Weather balloons are fixed by amateur radio operators e.g. also in 40 m height and antennas are fixed to them. Furthermore, weather balloons are used for height marking work, e.g. to mark a later wind turbine and to measure the actual wind strength over a longer period of time, e.g. at a height of 150 meters.

How high can a weather balloon fly?

Weather balloons are available in different sizes and therefore fly to different altitudes. The largest weather balloon available for maximum altitude is the Weather Balloon 3000. The Weather Balloon 3000 can reach altitudes of up to 40 altitude kilometers (24.9 ft) (131,233 ft), which is three times higher than commercial airliners fly.

How far can a weather balloon expand?

The world's largest weather balloon available is the Weather Balloon 3000, which can expand up to 14 meters (45.9 ft) in diameter at an altitude of 40 kilometers (24.9 mi) (131,233 ft)!

How do I fill a weather balloon?

In order to fill a weather balloon with the amount previously calculated with the Helium Calculator for your mission, the helium/ balloon gas from the gas bottle must be filled into the weather balloon in the correct amount. To take the right amount from the gas bottle, we need a Pressure Reducer, which is connected to the gas bottle. This allows you to precisely control the amount of gas that is filled into the weather balloon. A hose leads from the pressure reducer into the weather balloon, so that the helium/ balloon gas from the gas bottle can flow through the hose of the pressure reducer into the weather balloon.

How long does it take to fill a weather balloon?

This depends on the size of the weather balloon and the required amount of helium/ balloon gas. For small weather balloons, the filling process takes a few minutes, for large weather balloons such as the Weather Balloon 2000, the filling process should take about 15 to 20 minutes, depending on the adjusted flow rate.

What is the storage time of a weather balloon? How long can I store a weather balloon?

Provided the weather balloon has been stored dry at room temperature and sealed from direct sunlight in its original packaging, Stratoflights' high-quality weather balloons can be stored for up to 2 years without loss of quality.

How much lifting capacity does a weather balloon have?

The load capacity depends on the size of the weather balloon. The load capacity consists of the dead weight of the weather balloon and the payload, which is attached to the weather balloon. The Weather Balloon 2000 has a dead weight of 2,000 g (70.5 oz) and can carry a payload of 2,000 g (70.5 oz) and thus the carrying capacity is 4,000 g (141 oz).

How much weight can be attached to a weather balloon?

How much weight or payload can be attached to a weather balloon depends on the model of the weather balloon. For example, the Weather Balloon 2000 can carry a payload of 2,000 g (70.5 oz).

What can you attach to the weather balloon?

The payload of a weather balloon can be various. Weather services let measuring instruments and radiosondes rise with parachutes on meteorological balloons, schools design their own small probes with cameras and measuring equipment, amateur radio operators fix antennas on weather balloons. Art objects are also fixed to weather balloons in galleries as part of special exhibitions. Road construction companies use weather balloons to measure temperature and humidity at heights where bridges will later be built. The possibilities are endless.

Where to buy the helium or balloon gas for weather balloons?

At the gas retailers in your region. These can be small local suppliers, but also large gas suppliers such as Air Liquide and Linde Gas. Larger hardware store chains also carry balloon gas in large gas tanks.

Where to buy a weather balloon? Weather balloon for sale?

High quality weather balloons or meteorological weather balloons or also called stratospheric balloons, you can buy at Stratoflights. We offer weather balloons of different sizes to fit your mission.

What is the difference between a weather balloon and stratospheric balloon, high altitude balloon (HAB) and sounding balloon?

Weather balloons are often called meteorological weather balloons, high altitude balloons (HAB), sounding balloons and also stratospheric balloons. However, these are just synonyms, so there is no difference.

What colors are weather balloons available in?

Weather balloons are only available in white.

Is it possible to predict the flight path of weather balloons?

Yes, this is possible, even relatively accurately. For this purpose, you can use our tool Predicting the flight path and predict the flight route to within a few kilometers the day before the launch.

How far does a weather balloon fly? Flight distance of a meteorological balloon?

That depends on many factors: First, on the altitude and ascent speed of the weather balloon and the wind speeds, as well as from which directions the wind blows, whether the wind direction changes at different altitudes, etc. On average, one can assume an average flight distance between take-off and landing point of a weather balloon with payload and parachute at a place altitude of about 36 altitude kilometers (22.3 mi) (118,110 ft) at an ascent speed of 5 meters per second of about 80 kilometers (50 mi) as the crow flies. In the summer months, the flight distance is often far below 80 kilometers (50 mi) as the crow flies. In winter, the flight distance increases and longer distances are possible.

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