Engine testing underway on the world's biggest (and strangest) aircraft [VIDEO]

Working on the Stratolaunch’s PW4056 engines.

Engine testing has begun on the world’s newest, biggest, and definitely strangest, aircraft. And, yes, it’s a freighter.

Well, okay, it’s not going to be moving pallets of iPhones from Zhengzhou to Chicago and Frankfurt, but it will be carrying what could be called cargo: The Stratolaunch aircraft is designed to carry satellites to high altitude, from where they can be launched economically into low Earth orbit.

Stratolaunch said the engine testing to date has been carried out in three phases:

First as a ‘dry motor,’ using an auxiliary power unit to charge the engine.

Next, as a ‘wet motor,’ with the introduction of fuel.

Finally, each engine was started one at a time and allowed to idle.

In these initial tests, the company said each of the six engines operated as expected. The test program also included testing all six fuel tanks.

Testing of the flight control systems are now underway, and, over the next few months, engine testing will continue at gradually increasing power levels, with the goal of starting taxi tests in early 2018.

As mentioned above, this is a strange-looking aircraft. It has two fuselages, each about as long as a 747, but somewhat slimmed down. The total wingspan is 385 feet (117.4 meters), which includes the space between the two fuselages, where the payload will be hung from the connecting part of the wing. Other stats include:

Engines: Six Pratt & Whitney PW4056 engines

Empty weight: 500,000 pounds (227 tonnes)

Max takeoff weight: 1,300,000 pounds (590 tonnes)

Maximum payload: approximately 550,000 lbs (250 tonnes)

Length: 238 feet (72.5 meters)

Height: 50 feet (15.2 meters), ground to top of vertical tail

But those numbers, by themselves, just don’t convey the reality of this unique aircraft, so to save a few thousand words, here are some pictures and a video.

Here’s a shot of the aircraft during the engine tests.