Business, Media Criticism, Space

Another Stratolaunch Story

13 Comments

…at The Economist.

This is the first time that I’ve seen the aircraft called a “Stratolaunch.” I wonder if the correspondent knows something we don’t, or is just making a false inference? Also, I’m a little surprised that the editors don’t know the difference between a hanger and a hangar. Unless it’s a British spelling.

13 thoughts on “Another Stratolaunch Story”

  1. Noticed that they still called Scaled “Burt Rutan’s company” – um, Burt retired earlier this year, and technically Scaled has been a wholly-owned subsidiary of Northrop Grumman for a few years now.

    I confess that I’m concerned about the ability of the pilot to fly this undoubtedly very flexible airplane using mechanical flight controls (Scaled has a real phobia about using anything other than purely mechanical flight controls). I’m assuming that their flight envelope is going to be very small, dynamic pressure wise, to enable them to tailor the aeroelastics, but it’s still going to be an extremely tricky design job and piloting job.

    1. I don’t thing purely mechanical flight controls are viable for an aircraft of that size. At minimum you’d need hydraulic or electric amplifiers between the cockpit and control surfaces. Rigging the system with force feedback so if feels to the pilot like a pure mechanical linkage might be an option.

      1. Sorry, I should have been more clear: hydraulically boosted controls fit the Scaled mindset, but they won’t touch anything even as simple as a yaw damper for augmentation.

  3. As a (former) aeroelastician I’d have to 2nd Cthulhu’s concerns. Voyager had a nasty gust/PIO mode I recall, but NG certainly has the in-house expertise to model that kind of stuff.

    If the flexure extends into weird regimes, like Helios, NG might have to get a bit creative in their analysis.

    It has occurred to me that a couple of wing hinges would allow use of much smaller hangars, useful if they intend to stage this vehicle in various locations prior to launch.

  4. Voyager did have some nasty flying characteristics from what I’ve read. However, that was 25 years ago. Scaled has learned a lot about designing large composite airframes in that time and composite materials have advanced a great deal. The configuration is like a jumbo White Knight Two so they have already learned a lot about dual fuselage design. It’s a pretty rare configuration. Off hand, the only dual fuselage aircraft I can think of were the He-111Z and P-82 Twin Mustang of WWII and White Knight Two.

  5. I think that when the computer modeling is done they’re going to end up with a tailplane between the vertical stabilizers like practically every other twin-boom airplane out there, some very creative computer code driving a fly-by-wire system,, the fuselages closer together than shown, extremely restrictive weather requirements, or any or all of the above.

    That’s a lot of mass moving around if the two fuselages get into opposite-mode fugoids.

    Regards,
    Ric

    1. Like I said – Scaled won’t touch a stability augmentation system, let alone fly-by-wire. Aeroelastic coupling isn’t that big a deal at the phugoid frequencies, but it’s going to be significant with the short period. The rebound from dropping the rocket is going to be something to watch out for too.

  6. I imagine that if they’ve spent a fifty or a hundred million getting to a design review and it says they need augmentation or fly by wire, then it’ll get put in.

    What’s the rationale for using 747 fuselages though? Simple constant diameter sections are easy to design and manufacture, buying plans or reverse engineering an entire 747 fuselage would be opening a real can of worms.

    2. That was erronously reported in places like “Popular Mechanics.” From what I’ve read, they’re looking to buy 2 used 747s and salvage useful parts like the engines, cockpit, landing gear and the like.

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