The Douglas Skystreak (D-558-1 or D-558-I) was an American single-engine jet
research aircraft
An experimental aircraft is an aircraft intended for testing new aerospace technologies and design concepts.
The term ''research aircraft'' or ''testbed aircraft'', by contrast, generally denotes aircraft modified to perform scientific studies, ...
of the 1940s. It was designed in
1945
1945 marked the end of World War II and the fall of Nazi Germany and the Empire of Japan. It is also the only year in which nuclear weapons have been used in combat.
Events
Below, the events of World War II have the "WWII" prefix.
Januar ...
by the
Douglas Aircraft Company
The Douglas Aircraft Company was an American aerospace manufacturer based in Southern California. It was founded in 1921 by Donald Wills Douglas Sr. and later merged with McDonnell Aircraft in 1967 to form McDonnell Douglas; it then operated as ...
for the
U.S. Navy
The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage o ...
Bureau of Aeronautics, in conjunction with the
National Advisory Committee for Aeronautics
The National Advisory Committee for Aeronautics (NACA) was a United States federal agency founded on March 3, 1915, to undertake, promote, and institutionalize aeronautical research. On October 1, 1958, the agency was dissolved and its assets ...
(NACA). The Skystreaks were
turbojet
The turbojet is an airbreathing jet engine which is typically used in aircraft. It consists of a gas turbine with a propelling nozzle. The gas turbine has an air inlet which includes inlet guide vanes, a compressor, a combustion chamber, and ...
-powered aircraft that took off from the ground under their own power and had unswept flying surfaces.
Development
The D558 program was conceived as a joint NACA/U.S. Navy research program for
transonic
Transonic (or transsonic) flow is air flowing around an object at a speed that generates regions of both subsonic and supersonic airflow around that object. The exact range of speeds depends on the object's critical Mach number, but 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
air inlets and varying wing
airfoil
An airfoil (American English) or aerofoil (British English) is the cross-sectional shape of an object whose motion through a gas is capable of generating significant lift, such as a wing, a sail, or the blades of propeller, rotor, or turbine.
...
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. It was made of
HK31, which is 3%
thorium
Thorium is a weakly radioactive metallic chemical element with the symbol Th and atomic number 90. Thorium is silvery and tarnishes black when it is exposed to air, forming thorium dioxide; it is moderately soft and malleable and has a high me ...
and 1%
zirconium
Zirconium is a chemical element with the symbol Zr and atomic number 40. The name ''zirconium'' is taken from the name of the mineral zircon, the most important source of zirconium. The word is related to Persian '' zargun'' (zircon; ''zar-gun'', ...
and the rest magnesium, being much lighter than
inconel
Inconel is a registered trademark of Special Metals Corporation for a family of austenitic nickel-chromium-based superalloys.
Inconel alloys are oxidation-corrosion-resistant materials well suited for service in extreme environments subjected t ...
and having a much higher
heat capacity
Heat capacity or thermal capacity is a physical property of matter, defined as the amount of heat to be supplied to an object to produce a unit change in its temperature. The SI unit of heat capacity is joule per kelvin (J/K).
Heat capacity i ...
.
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 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 General Electric as the TG-180) — one of the first
axial-flow turbojet
An axial compressor is a gas compressor that can continuously pressurize gases. It is a rotating, airfoil-based compressor in which the gas or working fluid principally flows parallel to the axis of rotation, or axially. This differs from other ...
s of American origin — and carried 230 US gallons (871 L) of
jet fuel
Jet fuel or aviation turbine fuel (ATF, also abbreviated avtur) is a type of aviation fuel designed for use in aircraft powered by gas-turbine engines. It is colorless to straw-colored in appearance. The most commonly used fuels for commercial a ...
(kerosene).
Operational history
![Douglas D-558-I with pilots Carl and Cladwell 1947](https://upload.wikimedia.org/wikipedia/commons/4/4d/Douglas_D-558-I_with_pilots_Carl_and_Cladwell_1947.jpg)
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
Edwards Air Force Base (AFB) is a United States Air Force installation in California. Most of the base sits in Kern County, but its eastern end is in San Bernardino County and a southern arm is in Los Angeles County. The hub of the base is Ed ...
). Less than 4 months later, on August 20, this aircraft with Commander
Turner Caldwell, USN, reached flying D-558-1 #1. This was recognised as an official world
air speed record
An air speed record is the highest airspeed attained by an aircraft of a particular class. The rules for all official aviation records are defined by Fédération Aéronautique Internationale (FAI), which also ratifies any claims. Speed records ...
, as the World War II German
Me 163B V18 ''Komet'' rocket fighter prototype that was claimed to have reached in July 1944
did so in secrecy and not under the strict conditions that regulate official records (presence of FIA officials as observers, timed runs in two directions to cancel out wind speed, etc). The D-558-1 #1 Skystreak's record lasted 5 days, and was broken by then-Lieutenant Colonel
Marion Carl
Major General Marion Eugene Carl (November 1, 1915 – June 28, 1998) was an American military officer, World War II fighter ace, record-setting test pilot, and naval aviator. He was the United States Marine Corps' first ace in World War II.
Ear ...
, USMC, going 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
The National Naval Aviation Museum, formerly known as the National Museum of Naval Aviation and the Naval Aviation Museum, is a military and aerospace museum located at Naval Air Station Pensacola, Florida.
Founded in 1962 and moved to its curr ...
at
Naval Air Station Pensacola
Naval Air Station Pensacola or NAS Pensacola (formerly NAS/KNAS until changed circa 1970 to allow Nassau International Airport, now Lynden Pindling International Airport, to have IATA code NAS), "The Cradle of Naval Aviation", is a United State ...
,
Florida
Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and to ...
.
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
Events
January
* January 1 – A United Nations-sponsored ceasefire brings an end to the Indo-Pakistani War of 1947. The war results in a stalemate and the division of Kashmir, which still continues as of 2022.
* January 2 – Luis ...
through
1953
Events
January
* January 6 – The Asian Socialist Conference opens in Rangoon, Burma.
* January 12 – Estonian émigrés found a Estonian government-in-exile, government-in-exile in Oslo.
* January 14
** Marshal Josip Broz Tito i ...
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
The Carolinas Aviation Museum is an aviation museum on the grounds of Charlotte Douglas International Airport in Charlotte, North Carolina.
It is one of a few aviation museums located at an airport which serves as a major hub (Charlotte is the ...
located at the
Charlotte-Douglas International Airport
Charlotte Douglas International Airport (IATA: CLT, ICAO: KCLT, FAA LID: CLT), typically referred to as Charlotte Douglas, Douglas Airport, or simply CLT, is an international airport in Charlotte, North Carolina, located roughly six miles wes ...
(CLT) in
Charlotte, North Carolina
Charlotte ( ) is the most populous city in the U.S. state of North Carolina. Located in the Piedmont region, it is the county seat of Mecklenburg County. The population was 874,579 at the 2020 census, making Charlotte the 16th-most populo ...
.
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
Brigadier General Charles Elwood Yeager ( , February 13, 1923December 7, 2020) was a United States Air Force officer, flying ace, and record-setting test pilot who in October 1947 became the first pilot in history confirmed to have exceeded the ...
and the supersonic
Bell X-1
The Bell X-1 (Bell Model 44) is a rocket engine–powered aircraft, designated originally as the XS-1, and was a joint National Advisory Committee for Aeronautics– U.S. Army Air Forces–U.S. Air Force supersonic research project built by Be ...
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.
Aircraft Bureau Numbers (BuNo) and status
* D-558-1 Skystreak
** D-558-1 #1 - BuNo ''37970'' NACA-140, 101 flights (retired to
National Naval Aviation Museum
The National Naval Aviation Museum, formerly known as the National Museum of Naval Aviation and the Naval Aviation Museum, is a military and aerospace museum located at Naval Air Station Pensacola, Florida.
Founded in 1962 and moved to its curr ...
,
NAS Pensacola
Naval Air Station Pensacola or NAS Pensacola (formerly NAS/KNAS until changed circa 1970 to allow Nassau International Airport, now Lynden Pindling International Airport, to have IATA code NAS), "The Cradle of Naval Aviation", is a United State ...
, Florida)
** D-558-1 #2 - BuNo ''37971'' NACA-141, 46 flights (destroyed in crash, 3 May 1948)
** D-558-1 #3 - BuNo ''37972'' NACA-142, 81 flights (retired to
Carolinas Aviation Museum
The Carolinas Aviation Museum is an aviation museum on the grounds of Charlotte Douglas International Airport in Charlotte, North Carolina.
It is one of a few aviation museums located at an airport which serves as a major hub (Charlotte is the ...
,
Charlotte-Douglas International Airport
Charlotte Douglas International Airport (IATA: CLT, ICAO: KCLT, FAA LID: CLT), typically referred to as Charlotte Douglas, Douglas Airport, or simply CLT, is an international airport in Charlotte, North Carolina, located roughly six miles wes ...
, Charlotte, North Carolina)
** D-558-1 #4, #5, #6 Additional aircraft originally ordered but later cancelled.
Specifications (D-558-1 Skystreak)
See also
References
Further reading
*
External links
NASA Dryden D-558-1 gallery.
{{Authority control
D-558-1
1940s United States experimental aircraft
Single-engined jet aircraft
Low-wing aircraft
Aircraft first flown in 1947