You can ship just about anything by air. Letters, packages, cars, horses, construction equipment and even other airplanes can be shipped air freight. The planes that carry all of this stuff range from normal commercial airlineres to some amazing flying mutants!
Air freight can be separated into three main categories:
- Freight that rides on passenger airlines
- Freight that rides on dedicated cargo planes
- Huge payloads that ride in super cargo planes
In this edition of HowStuffWorks, we'll take a look at these three different types of freight and learn about the sometimes bizarre aircraft that carry them.
Passenger Airline Freight
Just about every passenger flight is carrying some freight along with the passengers and their baggage. The U.S. Postal Service alone leases space on 15,000 of the approximately 25,000 scheduled passenger flights each day. Commercial airlines make about 5 to 10 percent of their revenue from hauling freight.
When a package is shipped on your flight, it is usually consolidated with other packages and freight and packed into special containers that fit in the storage area under the passenger compartment. For instance, a Boeing 747-400 (one of the largest passenger planes) can hold 416 passengers along with 5,330 cubic feet (150 m3) of cargo. That's about as much cargo as can fit in two semi-truck trailers.
Most of the freight is stored in special containers shaped to fit themselves to the inside of the cargo hold. Some of the freight is also put on pallets, and loose items may be placed in any open spaces that remain.
The 747-400 can also be configured in "Combi" mode, in which some of the passenger compartment is used to store freight. In this mode, the plane can carry over 10,000 cubic feet (283 m3) of cargo and 266 passengers.
And it can hold a lot more cargo when configured as a dedicated cargo plane.
Shipping companies like FedEx and UPS own many different types of cargo planes. One of the larger ones is the Boeing 747. When configured as a freighter, the Boeing 747-400 can hold about 26,000 cubic feet (736 m3) of cargo. That's about as much as five semi trucks can haul.
The 747-400 can hold 30 pallets of goods on the main level. The pallets are 96 by 125 inches (2.4 m by 3.2 m) and up to 120-inches (3.05-m) tall. For shipping horses, there are special containers called airstables that connect to pallets and fit in the cargo hold. On the lower level, the plane can hold another five pallets along with 14 specially fitted containers, each up to 64 inches (1.6-m) tall. All of these goods are loaded through hatches in the side of the plane.
As you can see in the picture above, the plane can also open up its nose for the loading of large or irregularly shaped cargo.
Since there often isn't room to drive a forklift truck into the plane to load the pallets, the load floor is equipped with electric rollers. Once a pallet is pushed through the doorway, the electric rollers are used to move it to the front or rear of the cargo hold.
But for hauling really big cargo, you need a super transporter.
This is a class of plane designed purely for moving huge stuff. If you need to transport a helicopter, or even a plane, you need a Super Transporter.
This plane is built with a huge cargo area located above the cockpit, allowing freight to fill almost the full length of the plane. The giant door on the front of the cargo hold opens wide enough to get completely out of the way -- if an object will fit in the plane, it will fit through the door.
This plane can haul about 47 tons of cargo. That's a lot, but not enough to transport, say, a military tank. A tank can weigh 65 tons or more. For that, you need an even bigger transport plane.
World's Biggest Transporter
The world's biggest transport plane is the Antonov AN-225. With a cargo capacity of over 250 tons, this plane can haul not just one, but three or four military tanks.
This plane was originally designed to carry the Russian version of the space shuttle. Plans for the shuttle were put on hold, and the plane has been grounded since the early 1990s. The plane was recently restored, and it made its first test flight on May 7, 2001. Its wingspan is almost the length of a football field, and its cargo hold can fit 80 cars.
Now we've seen planes that haul everything from the postcard you sent your grandmother to battle tanks. You really can ship anything!
Related HowStuffWorks Links
- How Airports Work
- How Airlines Work
- How Airline Crews Work
- How Black Boxes Work
- How Air Traffic Control Works
- How Customs Works
- How Baggage Handling Works
- How the Federal Aviation Administration Works
- How Airport Security Works
- How Becoming a Pilot Works
- How Airplanes Work
- How Gas Turbine Engines (and Jet Engines) Work
Other Great Links
- Airbus Transport International
- British Airways
- Hong Kong International Airport
- Whither Cargo?
- Air Cargo, Air Freight, Fed-X and UPS Pictures
- Flying Tiger Line - Historical Pictures
- Cargo Loading System Pictures
- Lufthansa Cargo
- Airborne Express
- Boeing: Freighter Fleet
- Air Cargo World's Online Magazine
- World's Largest Cargo Aircraft Antonov AN-124-100