https://en.wikipedia.org/wiki/Douglas_D-558-1_Skystreak
The Douglas Skystreak (D-558-1 or D-558-I) was an American single-engine jet
research aircraft of the 1940s. It was designed in 1945 by the Douglas Aircraft
Company for the U.S. Navy Bureau of Aeronautics, in conjunction with the
National Advisory Committee for Aeronautics (NACA). The Skystreaks were
turbojet-powered aircraft that took off from the ground under their own power
and had unswept flying surfaces.
The D558 program was conceived as a joint NACA/U.S. Navy research program for
transonic and supersonic flight. As originally envisioned, there would be three
phases to the D558 program: a jet-powered airplane, a mixed rocket/jet-powered
configuration, and a design and mockup of a combat aircraft. A contract for
design and construction of six D558-1 aircraft for the first phase was issued on
22 June 1945. The original plan had been for six aircraft with a mixture of nose
and side inlets and varying wing airfoil sections. That plan was quickly reduced
to three aircraft of a single configuration with a nose inlet. Plans for the
second phase with mixed rocket/jet propulsion were also dropped. Instead, a new
aircraft, the D558-2, was designed with mixed rocket and jet propulsion for
supersonic flight.
Construction of the first 558-1 began in 1946 and was completed in January 1947.
The fuselage used magnesium alloys extensively, while the wings were fabricated
from more conventional aluminum alloys. The airframe was designed to withstand
unusually high loads of up to 18 times gravity due to the uncertainties of
transonic flight. The forward fuselage was designed so that it, including the
cockpit, could be jettisoned from the aircraft in an emergency. The aircraft
was configured to carry more than 500 lb of test equipment, including sensors
(primarily strain gauges and accelerometers) in 400 locations throughout the
aircraft. One wing was pierced by 400 small holes to enable aerodynamic pressure
data to be collected.
The Skystreaks were powered by one Allison J-35-A-11 engine (developed by
(kerosene).
National origin
United States
Manufacturer
Douglas Aircraft Company
First flight
14 April 1947
Status
Retired
Primary user
United States Navy
National Advisory Committee for Aeronautics
Number built
3
Developed into
Douglas D-558-2 Skyrocket
All the Skystreaks were initially painted scarlet, which led to the nickname
"crimson test tube." NACA later had the color of the Skystreaks changed to white
to improve optical tracking and photography. The first of three D-558-1
Skystreaks, BuNo 37970, made its maiden flight on 14 April 1947, at Muroc Army
Air Field (later named Edwards AFB). Less than 4 months later, on August 20,
this aircraft with Commander Turner Caldwell, USN, reached 640.744 miles per
hour (1,031.178 km/h) flying D-558-1 #1. This was recognised as an official
world speed record, as the World War II-era German Me 163A Komet rocket fighter
that reached 1004 km/h (624 mph) in October 1941 did so in secrecy. The D-558-1
#1 Skystreak's record lasted 5 days, and was broken by then-Lieutenant Colonel
Marion Carl, USMC, going 10 miles per hour (16 km/h) faster in D-558-1 #2, BuNo
37971. This aircraft was delivered to the NACA Muroc Flight Test Unit in April
1949 after 101 flights had been completed by the Navy, Air Force, and Douglas.
This aircraft was never flown by the NACA. The D-558-1 #1 is located at the
National Naval Aviation Museum at Naval Air Station Pensacola, Florida.
Following 27 flights by the Navy and Douglas the second D-558-1 aircraft was
delivered to the NACA in November 1947. The D-558-1 #2 underwent extensive
instrumentation by the NACA Muroc instrumentation section. The number 2
Skystreak made a total of 19 flights with the NACA before it crashed on takeoff
due to compressor disintegration on May 3, 1948, killing NACA pilot Howard C.
Lilly. The third D-558-I, BuNo 37972, aircraft was delivered to the NACA Muroc
Flight Test Unit in 1949 after three Douglas test pilots and Howard Lilly had
flown it. The number three aircraft took over the planned flight program of the
D-558-1 #2. From the first flight in 1949 through 1953 the third Skystreak was
flown in an intensive flight-research program by seven NACA test pilots, with a
great deal of useful data collected on high-subsonic handling. The D-558-1 #3
made a total of 78 research flights with the NACA before being retired on June
10, 1953. The third Skystreak is on display at Carolinas Aviation Museum located
at the Charlotte-Douglas International Airport (CLT) in Charlotte, North
Carolina.
The Skystreak reached Mach 0.99 in level flight, but only flew supersonic in a
dive. In the public mind, much of the research performed by the D-558-1
Skystreaks was quickly overshadowed by Chuck Yeager and the supersonic Bell X-1
rocket plane. However, the Skystreak performed an important role in aeronautical
research by flying for extended periods of time at transonic speeds, which freed
the X-1 to fly for limited periods at supersonic speeds.
Specifications (D-558-1 Skystreak)
General characteristics
Crew: one pilot
Payload: 500 lb of instruments (227 kg)
Length: 35 ft 8 in (10.87 m)
Wingspan: 25 ft 0 in (7.62 m)
Height: 12 ft 1 in (3.68 m)
Loaded weight: 9,750 lb (4,423 kg)
Max. takeoff weight: 10,105 lb (4,583 kg)
Performance
Maximum speed: 650 mph at sea level (1,050 km/h)
Stall speed: 137 mph (221 km/h)
Service ceiling: 45,700 ft (13,900 m)
Rate of climb: 9,220 ft/min (2,810 m/min)
Thrust/weight: 0.51
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