The world’s largest all-composite plane has been moved from its hangar prior to a series of aircraft fuelling tests.

At 238’ (76m) long and with a wingspan of 385’(118m), Stratolaunch will be powered by six Pratt & Whitney PW4056 engines and deliver payloads of up to approximately 550,000Ibs (249,475kg) into space.
“Over the past few weeks, we have removed the fabrication infrastructure, including the three-story scaffolding surrounding the aircraft, and rested the aircraft’s full weight on its 28 wheels for the first time,” said Jean Floyd, CEO, Stratolaunch Systems Corporation. “This was a crucial step in preparing the aircraft for ground testing, engine runs, taxi tests, and ultimately first flight.
“Once we achieved weight-on-wheels, it enabled us to weigh the Stratolaunch aircraft for the first time, coming in at approximately 500,000lbs (226,796kg). That may sound heavy, but remember that the Stratolaunch aircraft is the world’s largest plane by wingspan, measuring 385ft (118m). The aircraft is 238ft (76M) from nose to tail and stands 50ft (15m) tall from the ground to the top of the vertical tail.”

Floyd added that Stratolaunch is designed for a maximum take-off weight of 1,300,000lbs (589,670kg) and will be able to carry payloads up to approximately 550,000lbs (249,475kg).
“We will initially launch a single Orbital ATK Pegasus XL vehicle with the capability to launch up to three Pegasus vehicles in a single sortie mission,” he said. “We have already started preparations for launch vehicle delivery to our Mojave facilities. We’re actively exploring a broad spectrum of launch vehicles that will enable us to provide more flexibility to customers.”

According to company founder Paul Allen, the project’s objective is to ‘normalise’ access to low Earth orbit (LEO) with a reusable platform that is “a consistent, flexible and viable alternative to traditional ground-launched rockets.”
Allen, the co-founder of Microsoft, said the advantages to this approach include lower costs and more missions as the aircraft – with a range of up to 1,000 nautical miles – will be able to launch from different runways.
Stratolaunch, which is based at the Mojave Air & Space Port in California, is on track to perform its first launch as early as 2019.
Remarkable!
I do not like the design of this, it looks very flimsy, why they couldn’t join the tailplanes I do not know.
My exact thoughts also, Nick! In turbulence, the two fuselages could each begin oscillating about their yaw axes, or pitch axes in opposite directions resulting in large stresses in the joining wing. I too can’t understand why they didn’t move the tail-planes together while maintaining their control area and drag. Like the North American P-82 Twin Mustang of the 1940s!
I was thinking the same. I assume that wind tunnel testing of models prove the concept is viable, but it does potentially look like an unstable beast.
That is what happens when you start using carbon fibre. It is unbelievably strong!
Considering it’s the 21st centuary and this is an engineering magazine; is there any chance you could start using metric measurements in your articles?
We’ve now added those conversions. The Imperial quantities are quoted first because, as the US engineering sector uses these units, they are a more accurate descriptor of how the aircraft was specified.
I quite agree, I have used nothing but the SI system my entire working life. Why not specify a take off weight of 590Mg for clarity?
I prefer Tonnes for big masses !
Waste of money for R&D and manufacture. The Tool for intended ops does exist already.
Built in archaic ages, first flew on 21 December 1988.
It’s shorter in both length and wingspan, can fit “normal” airports and has a better payload characteristics.
Specifically designed to carry external cargo – 200 tonnes (piggy back). This cargo can have length of 70 m.
In addition to Nick Woodward comment, the Tool’s empennage design has a twin tail with an oversized, swept-back horizontal stabiliser.
The answer is:
An-225.
NIHS : Not Invented Here Syndrome
You can see the weak point just by looking at it. The potential forces on the central wing section are phenomenal. If you can’t join the tail planes then at least join the front end. Venom, vixen and vampire technology of the 50’s and 60’s look it up guys before someone is killed.
The best option is to join the tail, it would reduce stress induced warping in the fuselages. Any warping has the potential to adversely effect aerodynamic characteristics and induce cracking in the central wing spar. Lets see what ground and flight test data comes back and tells us hey?
Geez guys, stop whining, learn some imperial measurements, won’t hurt you, there’s nothing wrong with a metre and two inches as a measurement! Presumably the payload will sit somewhere between the two fuselages and will need anchor points or some sort of cradle between them both, this should join the two fuselages together, I don’t think they are going to hang 250 Tonnes off the wing
Fails the ‘looks right’ test, but looking forward to seeing it fly.
Isn’t it one of the amazing benefits of a journal like ours, that, via their comments it exposes us all to the thinking of other Engineers who have spent their lives in ‘different’ technologies and can stimulate our thinking. I do recall, in 1972/3 via the good offices of a University contemporary who worked there, giving a lecture (in Seattle!) on ‘textiles’ to aero-engineers. This was at the time that carbon-fibre and other ‘textile-related’ ultra high strength materials were first starting to appear in aero-space. the main point of my ‘talk’ was that they should NOT consider textiles as very-thin and flexible metal…but unique materials (they were used to designing in metal) that had unique properties and strengths if used most effectively. I hope I succeeded in convincing them!
Wasn’t there a twin-hulled boat -constructed in carbon fibre- in the S West (and funded/sponsored by Phillips of Eindhoven) which was prepared for some race and made it only a few miles before it ‘snapped?’ I know that’s in water, but…as JB says this certainly this does not look right, and probably isn’t!
I am surprised that the article does NOT mention the Rutan heritage, that can be seen with the naked eye!