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Douglas D-558-II Skyrocket

Douglas · Supersonic / High-Speed Research · USA · Early Jet (1946–1969)

Douglas D-558-II Skyrocket — Supersonic / High-Speed Research
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The Douglas D-558-II Skyrocket was a swept-wing, jet-and-rocket-powered research aircraft built for the U.S. Navy and NACA, and was the first piloted aircraft to fly twice the speed of sound. Three airframes were built between 1947 and 1948. On 20 November 1953 — three weeks before the 50th anniversary of the Wright Flyer — Scott Crossfield piloted the third Skyrocket to Mach 2.005 (1,291 mph) at 62,000 ft, beating the U.S. Air Force's X-1A to Mach 2 by 18 days and ensuring that the U.S. Navy got there first.

The D-558 programme was a phased Navy contract begun in 1945, structured in parallel to (and partly competing with) the Air Force's X-1 series. Phase 1 produced the D-558-I Skystreak, a straight-wing pure-jet design that set the world speed record at 650.6 mph in August 1947. Phase 2 — the D-558-II Skyrocket — added 35° wing sweep, a Reaction Motors LR8-RM-6 four-chamber liquid-propellant rocket (6,000 lbf), and a Westinghouse J34-WE-40 turbojet (3,000 lbf with afterburner) so the aircraft could take off conventionally and switch to rocket power for the speed runs. Phase 3 was cancelled before any hardware was built.

Three D-558-IIs were built (Bureau Numbers 37973, 37974, 37975). The first two flew with conventional ground takeoffs; the third was modified for air-launch from a P2B-1S Superfortress (a Navy version of the B-29) to extend rocket-burn time at altitude — the same air-launch technique the X-1 used. Scott Crossfield's Mach 2 flight on 20 November 1953 was conducted from this air-launch configuration at 32,000 ft, with all four rocket chambers running. Crossfield became the first man to Mach 2; he later flew the X-15 on its first powered flights and is one of the most decorated test pilots in U.S. aviation history.

The D-558-II returned a foundational dataset on transonic and supersonic swept-wing aerodynamics: pitch-up tendencies above Mach 1, longitudinal-control effectiveness loss, dynamic stability margins, and aerodynamic-heating profiles up to Mach 2. The data informed the design of every U.S. Navy supersonic fighter that followed, including the F-11 Tiger and the McDonnell F-4 Phantom II. Two of the three airframes survive: BuNo 37974 is at the Smithsonian's National Air and Space Museum (in storage at the Steven F. Udvar-Hazy Center), and the air-launched BuNo 37975 is mounted on a pole at the entrance to the Naval Air Weapons Station China Lake.

For Kids — a shorter, friendlier version

The Douglas D-558-II Skyrocket was a special research plane. It was built for the American Navy and a group called NACA. Engineers wanted to learn how planes behaved at very high speeds. Three Skyrockets were built between 1947 and 1948.

The Skyrocket had swept-back wings and two engines. One engine burned jet fuel. The other was a rocket engine. The jet engine helped the plane take off from a runway. Then the pilot could switch to rocket power to go much faster.

On November 20, 1953, a pilot named Scott Crossfield made history. He flew the Skyrocket faster than twice the speed of sound. That is faster than a rifle bullet! He reached about 1,291 miles per hour at 62,000 feet up in the sky.

This made the Skyrocket the first piloted plane ever to fly twice the speed of sound. It beat another American plane called the X-1A by 18 days. The Navy was very proud to get there first.

Two of the three Skyrockets still exist today. You can see them in museums. They remind us how brave pilots and smart engineers pushed the limits of flight.

Fun Facts

  • The Skyrocket was the first piloted plane to fly twice the speed of sound.
  • Pilot Scott Crossfield hit about 1,291 miles per hour during his record flight.
  • The Skyrocket had two engines — one jet and one rocket — working together.
  • The record flight happened just three weeks before the 50th birthday of the Wright brothers' first flight.
  • The Skyrocket flew faster than twice the speed of sound, faster than a rifle bullet!
  • Three Skyrockets were built, and two of them still survive in museums today.
  • The Skyrocket beat a rival Air Force plane to Mach 2 by only 18 days.
  • The plane flew as high as 62,000 feet — that is higher than most clouds you ever see.

Kids’ Questions

What made the Skyrocket so special?

The Skyrocket was the first piloted plane to fly twice the speed of sound. It used both a jet engine and a rocket engine to go super fast. No other crewed plane had ever gone that fast before.

Who flew the Skyrocket on its big record flight?

A pilot named Scott Crossfield flew the Skyrocket on its famous record-breaking flight. He made the flight on November 20, 1953. He was very brave to fly at such an amazing speed.

Can I see a real Skyrocket anywhere?

Yes! Two of the three Skyrockets still exist in museums. You can visit them and see the real planes up close. It is a great way to learn about the history of fast flight.

How did the Skyrocket take off if it had a rocket engine?

The Skyrocket used its jet engine to take off from a normal runway. Once it was high in the sky, the pilot could switch on the rocket engine. This two-engine design made it very flexible.

Variants

BuNo 37973
First Skyrocket built. Conventional ground takeoff, J34 turbojet only at first; rocket motor added later. First flight 4 February 1948 with John F. Martin. Flown by Douglas and Navy through 1953.
BuNo 37974
Second airframe. Mixed jet+rocket powerplant; ground-takeoff configuration. Now in storage at the Smithsonian's Steven F. Udvar-Hazy Center.
BuNo 37975
Third airframe, modified for air-launch from a P2B-1S Superfortress. Flew Crossfield's 20 November 1953 Mach 2 flight. Preserved at NAWS China Lake on a static-display pylon.

Notable Operators

United States Navy
Sponsored the D-558 programme as a Navy parallel to the USAF X-1 series. Conducted early performance flying with Marion Carl and other Navy test pilots before transferring the airframes to NACA.
NACA (later NASA)
Operated the Skyrockets from the High-Speed Flight Research Station at Edwards AFB. NACA pilot Scott Crossfield made the Mach 2 flight on 20 November 1953.

Frequently Asked Questions

Who first flew Mach 2?

NACA test pilot A. Scott Crossfield, on 20 November 1953, in the third D-558-II Skyrocket (BuNo 37975). He reached Mach 2.005 (1,291 mph) at 62,000 ft after air-launching from a P2B-1S mother ship over Edwards AFB. The Air Force's X-1A reached Mach 2.44 with Chuck Yeager 18 days later, but Crossfield held the "first to Mach 2" record.

What powered the D-558-II?

A Reaction Motors LR8-RM-6 four-chamber liquid-propellant rocket (6,000 lbf, burning liquid oxygen and an ethyl alcohol/water fuel) plus, on the first two airframes, a Westinghouse J34-WE-40 turbojet (3,000 lbf with afterburner). The third airframe ran rocket-only after its air-launch modification.

How was the D-558-II launched?

Two configurations: conventional ground takeoff using the J34 turbojet (first two airframes), and air-launch from a P2B-1S Superfortress mother ship at about 32,000 ft (third airframe). The air-launch configuration extended rocket-burn time at altitude and made the Mach 2 flight possible.

How is the Skyrocket different from the Skystreak?

The Skystreak (D-558-I) is the earlier straight-wing pure-jet phase-1 design that set a 650.6 mph world record in 1947. The Skyrocket (D-558-II) added 35° wing sweep and a rocket motor for phase 2 of the Navy's research-aircraft programme. Both were Douglas products; both were funded by the Navy/NACA.

Where can I see a D-558-II Skyrocket?

Two of the three airframes survive: BuNo 37974 is in storage at the Smithsonian's Steven F. Udvar-Hazy Center near Washington Dulles, and BuNo 37975 is on outdoor static display at NAWS China Lake, California (NASA Armstrong fact sheet).

Sources

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