Rigid, Hydrogen Based, Moored Balloon

[GTeclips]

Hello.

I've regained a certain interest in lighter-than-air-craft recently. To satisfy this interest, I wish to construct a small, rigid, unmanned, moored, hydrogen balloon within the bounds of reason. I'm most definitely not an engineer to any extent, and as such, I have many questions.

First, is hydrogen too dangerous to even consider as a lifting gas in a tethered balloon? I realize hydrogen is looked down upon as a lifting gas for obvious reasons, but the fact is, many airship designs safely used it. Take zeppelins for example, of course there is the tragic Hindenburg (of which a source of ignition has not been determined, so I would not like it mentioned any further), and many early zeppelins met a flaming end, but many sophisticated hydrogen based designs safely transported passengers all around the world, both commercially and militarily.

Second question, which ties with the first, is hydrogen a legal lifting gas in the United States? Are there separate regulations for manned and unmanned balloons? Also, are there any FAA regulations for unmanned tethered balloons? There were not any that I could find.

Third, is a rigid tethered balloon even practical? This may sound like a foolish idea, but it would be used for experimental purposes. If it were within the bounds of reason, what might the frame look like (i.e. material, and wire size.)

Fourth, what is the buoyancy of hydrogen, assuming 100-1,000 meters above sea level and average equatorial air pressure and temperature. If what I hear is truth, this should be around 1.1 kg per cubic meter (or 0.075 lb. per cubic foot.)

Finally (thank you for sticking with me thus far), what material might the envelope be made of, and how could I stitch it together with hydrogen proof seams? I hear that neoprene might suite this purpose well.

Once again, thank you for reading through this mass of questions.

 

[AlephZero]

Also, are there any FAA regulations for unmanned tethered balloons? There were not any that I could find.

What regulations apply wlll depend on what altitude it is flying at, how big it is, and what might happen to it if the tether breaks. If there is any chance that it will get into controlled airspace, the "authorities" will most definitely be interested in it!

Talk to air traffic control at your nearest airfleld, or to a local flying club.

I'm not in the US so I don't know the specific regulations, but I would guess you can do pretty much what you like with a small balloon below say 500 ft, so long as you stay a few miles away from airfields. Even then, you might need to notify somebody when and where you plan to fly it.

 

[GTeclips]

Thank you very much, that clears that issue.

 

[AlephZero]

The relevant section of the FAA regs is part 101. http://www.chem.hawaii.edu/uham/part101.html

 

[alphy]

Hello,

Thank you for sharing your interest in lighter-than-air-craft and your desire to construct a small, rigid, unmanned, moored, hydrogen balloon. I would like to provide some insight and answer your questions to the best of my knowledge.

First, regarding the use of hydrogen as a lifting gas, it is true that it has been used in the past for airships and has shown to be an efficient lifting gas. However, it is also important to note that hydrogen is highly flammable and poses a significant safety risk. The decision to use hydrogen as a lifting gas should be carefully considered and all necessary safety precautions should be taken.

In the United States, the use of hydrogen as a lifting gas for manned balloons is regulated by the Federal Aviation Administration (FAA). There are specific regulations and guidelines that must be followed for the safe use of hydrogen in manned balloons. As for unmanned balloons, there may not be separate regulations for hydrogen-based lifting gases specifically, but there are likely regulations that cover the use of flammable gases in unmanned aircraft.

Regarding the practicality of a rigid tethered balloon, it is certainly possible to construct one for experimental purposes. The frame could be made of lightweight and strong materials such as aluminum or carbon fiber, and the wire size would depend on the size and weight of the balloon.

The buoyancy of hydrogen depends on various factors such as altitude, temperature, and air pressure. At 100-1,000 meters above sea level and average equatorial air pressure and temperature, the buoyancy of hydrogen is approximately 1.1 kg per cubic meter. However, it is important to note that these values may vary and should be carefully calculated for your specific balloon design.

For the envelope of the balloon, neoprene could be a suitable material as it is lightweight, flexible, and has good gas barrier properties. As for stitching, special hydrogen-proof seams or tapes could be used to ensure the safety of the balloon.

I hope this information helps answer your questions and provides some guidance for your project. It is always important to thoroughly research and consider all safety precautions when working with hydrogen or any other potentially hazardous materials. Best of luck with your project!