X-37B, Dream Chaser, and all other winged/lifting body RVs need to be launched inside fairings because if the lifting surface is exposed to the airflow it renders the stack aerodynamically unstable in pitch, like an arrow with the feathers in the front. The engines on a normal booster can't swivel far enough or fast enough to keep on course during the atmospheric part of the flight.A possible solution was tried on the X-20 where huge tail fins were added to the various proposed Titan boosters to counteract this effect. But wind-tunnel tests showed there might be dangerous interactions between the wing wakes and the fins which couldn't be modeled in those days. The same issue helped kill the winged flyback booster for Shuttle.The fairing makes designing an abort system for a manned winged RV very difficult (as does the lack of parachutes). That is why NASA accepted the cargo version of Dream Chaser, but rejected the manned version. The extra weight and danger of the wing folding mechanism was probably a factor too. Carrier aircraft wings don't have to endure reentry heating.Note that Sierra Nevada management claims they have a solution to the problem -- but they have never stated what that solution is.
Ok so SpaceX won a launch of the x37b todayishhttp://www.cnbc.com/2017/06/06/spacex-launches-us-air-force-x-37b-space-plane.htmlHas anyone read the contract?
Quote from: BobHk on 06/06/2017 11:30 pmOk so SpaceX won a launch of the x37b todayishhttp://www.cnbc.com/2017/06/06/spacex-launches-us-air-force-x-37b-space-plane.htmlHas anyone read the contract?Wrong takeaway. SpaceX is launching an X37B in August. This information came out recently.This doesn't imply SpaceX was just awarded this launch. This could have taken place 6-24 months ago, was kept a secret and just became public knowledge.As much as I would love if that's a reuse booster launch and that's how USAF cut the launch line, this doesn't seem likely given how recent the SES-10 launch was.Just saying.
X-37B, Dream Chaser, and all other winged/lifting body RVs need to be launched inside fairings because if the lifting surface is exposed to the airflow it renders the stack aerodynamically unstable in pitch, like an arrow with the feathers in the front. The engines on a normal booster can't swivel far enough or fast enough to keep on course during the atmospheric part of the flight.A possible solution was tried on the X-20 where huge tail fins were added to the various proposed Titan boosters to counteract this effect. But wind-tunnel tests showed there might be dangerous interactions between the wing wakes and the fins which couldn't be modeled in those days. The same issue helped kill the winged flyback booster for Shuttle.Note that Sierra Nevada management claims they have a solution to the problem -- but they have never stated what that solution is.
In theory, it should be possible to make the stack more stable with an exposed spaceplane.
Quote from: Arch Admiral on 06/06/2017 11:34 pmX-37B, Dream Chaser, and all other winged/lifting body RVs need to be launched inside fairings because if the lifting surface is exposed to the airflow it renders the stack aerodynamically unstable in pitch, like an arrow with the feathers in the front. The engines on a normal booster can't swivel far enough or fast enough to keep on course during the atmospheric part of the flight.The BORs were launched unshrouded.
X-37B, Dream Chaser, and all other winged/lifting body RVs need to be launched inside fairings because if the lifting surface is exposed to the airflow it renders the stack aerodynamically unstable in pitch, like an arrow with the feathers in the front. The engines on a normal booster can't swivel far enough or fast enough to keep on course during the atmospheric part of the flight.
And part of the reason the Saturn IB's first stage was tons lighter than the Saturn I's was that the former was never envisioned as a launch vehicle for the winged Dyna-Soar. I'll bet that whatever boosted BOR was built like a battleship.
Quote from: GClark on 06/07/2017 04:38 amQuote from: Arch Admiral on 06/06/2017 11:34 pmX-37B, Dream Chaser, and all other winged/lifting body RVs need to be launched inside fairings because if the lifting surface is exposed to the airflow it renders the stack aerodynamically unstable in pitch, like an arrow with the feathers in the front. The engines on a normal booster can't swivel far enough or fast enough to keep on course during the atmospheric part of the flight.The BORs were launched unshrouded.And part of the reason the Saturn IB's first stage was tons lighter than the Saturn I's was that the former was never envisioned as a launch vehicle for the winged Dyna-Soar. I'll bet that whatever boosted BOR was built like a battleship.
Wasn't X-37B initially supposed to launch unfaired on Delta II? How were the aerodynamics handled in that proposal?
Thinking about this development, a cheap reusable booster like F9 would allow the Air Force to have a wing of X-37Bs
Suborbital i guess, but you could maybe do a single pass over a country like SR-71.
Jeesh, just because the X-37 changed launchers doesn't mean it can do more than before.It can only carry 500lb of payload and that includes the attach hardware (remember the shuttle?)A Pegasus could launch a spacecraft with the same payload mass.
Quote from: Jim on 06/07/2017 05:52 pmJeesh, just because the X-37 changed launchers doesn't mean it can do more than before.It can only carry 500lb of payload and that includes the attach hardware (remember the shuttle?)A Pegasus could launch a spacecraft with the same payload mass.TWO or three for one pricing would allow shorter missions with more prop available to change orbit during any given mission. Correct?
