Slashdot Mirror
Suborbital Spaceflight Update
HobbySpacer writes "Burt Rutan's group has fixed a problem with the SpaceShipOne and recently carried out a successful drop test. Ground studies involved tests with CFD - "creative Ford driving" using a Ford-250 pickup truck. Other suborbital news includes the announcement of plans to follow the X PRIZE competition with an annual X PRIZE Cup event in which rocket teams will compete in an air show type format. In Japan the RVT (Reusable Vehicle Test) just completed its third short hop (in Japanese) within a week. (English reports on the first and second flights.) The liquid hydrogen/liquid oxygen powered vehicle seeks to develop robust, reusable technologies for vertical takeoff and landing rockets. It and subsequent vehicles will gradually expand the flight envelope to high altitudes."
CFD, for the curious, tends to stand for "Computational Fluid Dynamics" for most companies dealing with dynamics testing.
:)
The 'Fluid' is slightly misleading, as most packages will happily simulate gasses as well, thus enabling you to check the behavior of air around your airborne vehicle of choice.
But if dropping an old Ford does the trick for them, then what the heck
Nothing is mentioned about static testing of the engine; what the article talks about is that in-flight ignition of the engine hasn't been tested yet. I'd assume that whoever's making the engine has done plenty of static (test-stand) testing.
"They redundantly repeated themselves over and over again incessantly without end ad infinitum" -- ibid.
I don't think anyone knows for sure but Paul Allen is speculated to be the backer behind Rutan. The article goes on to say that Internet tycoon types with entirely too much money on their hands seem to be the primary funders of this kind of thing.
How does Rutan get funding? He is Burt Rutan. He has a proven track record. There are THOUSANDS of his Airplanes flying. If you look at all the VariEzes, Long Ezes, Quickies, Q2s, and even Nat Puffer pays him a royalty on his designs. Add in all the work he has done for NASA, and the DOD and he has one heck of a track record.
As far as the Aerospce circles you run in not looking at Rutan's seriously what freaking circle is that. The man has done work for NASA, Northrop, and Boeing!!!
Has your group built anything that flys yet? Carries a useful load?
Rutan built a plane that carried two people around the world on one tank of gas. In most Aerospace circles his is the Man!!.
See my blog http://ilovecookes.blogspot.com/ for light hearted technical information.
He means systems like interval arithmetic whereby you represent a Real number as an interval bounded by two machine floating point numbers.
Once upon a time NASA thought this way too.
One of the early lifting body X-plane designs was tested by towing it behind a car like a glider...
RedFive jedi_knight111@hotmail.com
They have tested the engines, on the ground. It's not very likely they'll go "too far" because they're just not carrying enough fuel.
The bulk of the heat of orbital reentry stems from the tangiental velocity (motion 'parallel' to the ground) that's necessary to maintain orbit in the first place. The suborbital flights lack this component...conceptually we can think of them as flying straight up and dropping straight down (in reality there's some downrange distance, but it's modest, obviously, compared to an orbital flight)...so the only heat to be dissipated is from the craft's nearly unimpeded downward acceleration in the uppermost atmosphere as it drops into progressively thicker air.
Terminal velocity will vary with each vehicle design and flight plan, but in all cases will be less than the tangiental velocity of an orbiting craft.
It will be toasty no doubt, but not so much as to require the use of exotic materials (thermal tiles as on the Shuttle, etc.)
It takes about 8 times as much energy to get into orbit as it does to achieve the X-Prize parameters. You can't go that far wrong.
Still, you do have to worry about re-entry heating, even at "only" Mach 3.5. Rutan's ship will have an ablative coating that sublimates away, carrying heat, for the hottest parts of the trip -- Rutan's ship needs this as it is made of composites that cannot tolerate even moderately high temperatures. This ablative coating would be applied every flight. The X-15 used a similar coating for its highest speed flights. As others note, the X-15 flight profile is very similar the profile for Rutan's SpaceShip 1.
The Armadillo aerospace vehicle uses aluminum, and is massive enough that there is enough of a heat sink that it won't get too hot for the short time there is significant aerodynamic heating.
thad
I love Mondays. On a Monday, anything is possible.
Burt Rutan's X-Prize vehicle is being funded by an anonymous donor. The expected final cost is around $20M, somewhat more than the $10M prize if Spaceship 1 actually wins the contest.
Note too that Rutan has been involved in space work before. The wing and tail surfaces of the Pegasus orbital launch vehicle are built by Rutan, as was the aeroshell of the DC-X vertical takeoff/landing test vehicle.
Rutan is also working on something called RASCAL, a grown-up version of the X-Prize system. It uses four large military turbojet engines to get up to Mach 3.5, in a very similar flight profile to SpaceShip 1, to act as the first stage of an orbital launcher. He intends to get Mach 3.5 performance out of normal turbojets at very high altitudes by using water and LOX injection, a concept that has been around since the late 50's, but one that nobody has put into practice.
thad
I love Mondays. On a Monday, anything is possible.