4.4 KiB
| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| North American DC-3 | 5/5 | https://en.wikipedia.org/wiki/North_American_DC-3 | reference | science, encyclopedia | 2026-05-05T13:21:41.394188+00:00 | kb-cron |
== Description == The DC-3 was a two-stage vehicle with a large booster and smaller shuttle/orbiter of overall similar design. Both were similar to "jumbo jets" in layout in general terms, with their large cylindrical fuselage containing fuel tanks instead of passengers or cargo. The bottom of the fuselage was flattened for re-entry aerodynamics, with a slight upward toward the nose in early models. The wings were low-mounted, in-line with the bottom of the fuselage, with a 14 degree rearward sweep on the front and no sweep on the back. The general layout of the wing planform was similar to the original DC-3. The empennage was a conventional three-surface unit, although in the original MSC-001 design the delta-shaped horizontal stabilizer was located at the bottom of the fuselage and served double-duty in protecting the rear-mounted engines during re-entry. Later versions did not generally include this feature, and used more conventional surfaces mid-mounted on the fuselage. The orbiter carried a crew of two, and had accommodations for up to ten passengers. A cargo area was mounted in the middle of the craft between the liquid hydrogen (LH2) tank behind it, and a combined LH2/liquid oxygen tank in front of it. This arrangement was used in order to center the cargo over the wing, with the heavier oxygen and crew compartment balancing the weight of the engines. The lighter weight hydrogen then filled out the rest of the internal space. The booster had no cargo area, so it used a simpler arrangement of tankage with a single LH2 tank at the rear. The booster normally flew uncrewed, but included a two-person cockpit area that was used during ferry flights. The orbiter was powered by two modified XLR-129 engines with the thrust increased from 250,000 to 300,000 lbf, two 15,000 lbf RL-10 orbital manoeuvring engines, and six Rolls-Royce RB162 jet engines for landing. The booster used eleven of the same XLR-129 engines, and four Pratt & Whitney JT8D for landing. XLR-129s on both the shuttle and booster were fired for vertical take-off. The orbiter was mounted relatively far forward for launch, its tail in-line with the booster's wings. The combined weight at launch would be about 2,030 tons. The orbiter would re-enter nose-high at an angle of about 60 degrees above horizontal, decelerating at a peak of 2G until it reached low subsonic speeds at 40,000 ft. At this point the forward speed of the craft would be very low, so the nose was pitched down and the orbiter dove to pick up airspeed over the wings and transition to level flight. Expected re-entry heating rates on the orbiter were 1650 deg C on the leading edge, and 790 deg C over 80% of the lower surface. In order to maximize overall performance, the booster released the orbiter at Mach 10 and 45 miles altitude. This required the booster to carry a complete thermal protection system in order to re-enter for landing. Both the orbiter and booster were to be protected with the LI-1500 silica tiles similar to those eventually used on the Space Shuttle, a design that had recently been introduced by Lockheed and quickly became a baseline design for all of the shuttle contenders. As a result, both airframes were able to be built out of aluminum, greatly reducing airframe cost. Both craft carried just enough JP-4 for landing go-around. Both could also carry increased loads of JP-4 for test flights or ferrying. After dispatching the orbiter the booster would be too far down-range to easily turn around and return to Kennedy, so the normal mission profile had it coast across the ocean, land automatically, refuel and pick up a crew, and then be flown back to Kennedy on its JT8D engines. Lockheed estimated that development and initial production would cost $5.912 billion over a period from 1970 to 1975. A fleet of six orbiters and four boosters would have supported a launch rate of 50 flights per year.
== References == Maxime Faget, "Space Shuttle: A New Configuration", Astronautics & Aeronautics, January 1970, p. 52 Marcus Lindroos, "MSC/North America Concept-A, 'DC-3'", 21 January 2003 (has 4 refs) "Shuttle", astronautix.com Archived 2012-03-13 at the Wayback Machine
== External links == The DC-3 fully reusable Space Shuttle early concept, video rendering by Hazegrayart