How an airship flies — design, operating principle and control

An airship is one of the oldest yet remarkably efficient types of aircraft, able to stay aloft thanks to buoyancy (Archimedes’ principle). Unlike airplanes, it does not need constant motion to fly; it can hover, move slowly, and maneuver. In this article, we look at how an airship is built, what makes it rise, how it moves and is controlled, and how modern models differ from the classics.

An airship rises thanks to lift based on Archimedes’ principle: a body immersed in a liquid or gas displaces a volume of the medium equal to its own volume and experiences an upward force equal to the weight of the displaced medium.

In the case of an airship:

✔ The envelope is filled with a light gas (for example, helium or hydrogen) that is lighter than the surrounding air.

✔ The weight of the displaced air turns out to be greater than the weight of the airship itself (including the gas, the envelope, the gondola, and the payload).

✔ Excess buoyant lift arises, which carries the craft upward.

The pressure inside the gas cells is maintained at a level that keeps their shape and volume; the design provides for compensating pressure changes during climb and descent.

The main gases used to fill airships:

Hydrogen — the lightest gas, providing maximum lift.

✅ Pros: very high lifting capacity.

❌ Cons: extremely explosive (the Hindenburg disaster in 1937 became a turning point).

Used in the early 20th century, but today is almost never employed.

Helium — an inert, nonflammable gas, the second-lightest after hydrogen.

✅ Pros: safe, stable.

❌ Cons: lifting capacity about 8% less than hydrogen; more expensive and harder to obtain.

Modern airships are almost always filled with helium.

For propulsion, an airship is equipped with an engine and propellers (airscrews).

• Gasoline/internal combustion engines — used in early models.

• Diesel engines — more economical, used in modern heavy airships.

• Electric motors — increasingly used in new eco-friendly designs (for example, airships for environmental monitoring).

• Mounted on the gondola or on outriggers.

• May be fixed or controllable (thrust vectoring) — tilting propellers allow an airship to move forward, backward, sideways, and even hover.

• Some modern designs use multiple propellers for better maneuverability.

Propellers generate thrust that pushes the airship forward, sideways, or backward depending on rotation and angle.

Main parts of an airship:

1. Envelope — a sealed outer skin made of strong, lightweight, UV‑resistant material (for example, polyester or multilayer composites). It protects the internal cells and gives the craft its aerodynamic shape.

2. Gas cells — inside the envelope are one or more flexible cells filled with helium (or hydrogen). They do not tension the envelope; they simply fill its volume.

3. Ballonets (air cells / air bags) — additional air bladders inside the envelope that are inflated or deflated to regulate pressure and lift.

4. Gondola (car) — the cabin suspended from the envelope that houses the crew, passengers, engines, instruments, and control systems.

5. Fin and stabilizers — rigid tail elements that ensure stability. Mounted on the fin are:

• Rudders (vertical)

• Elevators (horizontal)

6. Suspension and rigging — connects all components and distributes loads.

Airship control includes:

• Control surfaces:

- Rudder — yaws the airship left/right.

- Elevator — raises or lowers the nose (pitch), helping to climb or descend.

• Altitude control:

- Ballast — water or sand is dropped to reduce weight and climb.

- Gas cells and ballonets — as the airship climbs, air in the ballonets expands and is vented. During descent, air is pumped in to maintain pressure.

- Pressure management — a ventilation system lets air in or out of the ballonets to regulate the craft’s overall density.

• Lines and mooring:

- During landing and while parked, the airship is held by lines and a ground crew.

- A mast system is sometimes used — the airship is secured to a high mast like a ship to a quay.

1. The airship is held on the ground by lines.

2. Engines are started — thrust is generated.

3. Buoyant lift is already acting, but the weight of the gondola and ballast holds the craft down.

4. Ballast (water, sand) is gradually dropped, making the airship lighter.

5. With sufficient thrust and lift, the craft leaves the ground.

6. Control surfaces help align the course and begin flight.

1. The airship descends, reducing thrust.

2. The ground crew catches the mooring lines.

3. The craft is gradually secured and can be fastened to a mast.

4. If necessary, air is added to the ballonets to prevent the envelope from sagging.

Modern airships differ markedly from older models in six key ways.

• Rigid or semi‑rigid structure — many new designs have a framework (for example, Zeppelin NT), which increases strength and stability.

• Controllable propellers — enable vertical flight, lateral movement, and hovering.

• Electric motors and hybrid powertrains — reduce noise and emissions.

• Modern materials — composite envelopes resistant to weather and UV radiation.

• Automated control systems — GPS, pressure sensors, autopilot.

• Applications — advertising, surveillance, environmental monitoring, tourism, and cargo transport to hard‑to‑reach regions.

• Long, cigar‑shaped form with a streamlined nose and tail.

• Smooth envelope, often white (to reflect sunlight).

• Tail fin with control surfaces (vertical and horizontal).

• On the sides or below — the gondola (car), suspended on cables.

• Propellers may be visible on the sides or at the rear.

• The gondola is clearly visible with windows, landing lights, and sometimes landing gear.

• Cables run from the gondola to the envelope.

• Propellers point downward or aft.

• Service hatches, sensors, and antennas may be located on the envelope.

Modern airships are often used for aerial photography, and high‑resolution images are readily available — from below, they resemble a “flying cigar‑shaped bus with a gondola.”

An airship is a unique aircraft that combines buoyancy, aerodynamics, and engineering mastery. By using light gases, engines, and precise control, it can climb smoothly, hover, and maneuver. Modern technologies have made airships safer, more efficient, and more promising, opening up new possibilities for their use in the 21st century.

Want to take part in producing airships and earn income from their operation? Join via the link by becoming an investor or a partner of the New Generation Airships' project.