The Hughes . MD Helicopters Model 500 became a commercial success for its time in the mid-to-latter stages of the Cold War years (1947-1991). The series was born in a 1950s United States Army requirement seeking a successor for its expiring line of Bell OH-13 "Sioux" light helicopters then in service (detailed elsewhere on this site). Developed from the Bell Model 407, these extremely-light helicopters were developed after the close of World War 2 (1939-1945) and were subsequently produced in over 2,400 examples for a myriad of global operators. To find its replacement, the Army established the "Light Observation Helicopter" (LOH) program.
A design from Bell, Hiller, and Hughes were selected for head-to-head testing by the Army (the Hughes entry was the "Model 369", to become the "YHO-6" and, finally, the "YOH-6"). Testing took place at Camp Rucker in Alabama to which the Hiller and Hughes designs were selected for further evaluation. The Hughes submission was eventually declared the winner for what was "Round 1" of the selection process. In 1965, this helicopter was officially designated the OH-6A "Cayuse" (detailed elsewhere on this site) and taken into service by the United States Army.
As an aside, the LOH program was revisited in 1967 by the Army to pit Hiller versus Bell. Bell won out with their Model 206A which was inducted into Army service as the OH-58A "Kiowa" - leading the Army to field two light helicopter types for several decades - though the selection of the Bell model did impact the number of Hughes OH-6s originally planned for procurement.
The Cayuse went airborne for the first time in February of 1963 but even before this the Hughes team was envisioning a civilian marketplace form. The designation of "Hughes 500" (or "Model 500") was assigned to the offshoot which, in form and function, was more or less faithful to the military version. Internally, the cabin could be configured to seat five to seven personnel with the crew of two seated at front in a side-by-side arrangement. As with the Cayuse, the Model 500 showcased a teardrop-shaped fuselage with a heavily-windowed front section and hinged side-opening doors for passengers and crew alike. The engine was fitted to the upper aft-half of the fuselage and drove a multi-bladed main rotor sat close to the fuselage roof and a two-bladed tail rotor offset to portside along the tail fin. The powerplant exhausted through a port under the tail stem. The undercarriage was of a simple four-point skid arrangement which made the little helicopter somewhat rugged and more economical to maintain.
Type certification was gained in 1966 with the Model 369H, becoming the Model 500C in service. This mark seated five passengers and was powered by a single Allison 250-C18B series engine developing 317 horsepower. In 1968 arrived an export-minded militarized form of this helicopter in the Model 500M "Defender". In 1969, an improved Model 500C was unveiled with an Allison 250-C20 engine of 400 horsepower. That same year, another related version appeared with more expensive surroundings for the cabin.
In 1976 arrived the Model 500D which sported a redesigned nose. This variant carried an Allison 250-C29B of 420 horsepower. The Model 500E was based in the 500D with a revised nose and intended for VIP / business market travel. This model was type certified in 1982.
The Model 500N lacked a traditional tail rotor and managed torque through a vented tail unit (NOTAR = "NO Tail Rotor"). This model achieved certification in 1991 and carried an Allison / Rolls-Royce 250-C20R/2 engine of 450 horsepower output. The Model 530F was developed for "High-and-High" operating environments and based in the Model 500E. This was powered by an Allison / Rolls-Royce 250-C30P engine of 650 horsepower. Type certification was had in 1984.
That same year, the Hughes Helicopter Division was taken over by McDonnell Douglas (MD) which, in turn, changed designations of the Model 500 line (as in "MD 500").
Foreign production was had in both Italy and Japan. In the former, this was branded under Breda Nardi (pre-Agusta helicopters merger) and covered the Model 500E airframe while, in the latter, Kawasaki Heavy Industries (KHI) of Japan took to local, license production of the helicopter as the Kawasaki-Hughes 396HS.
The Model 500F has also served as the basis for the Unmanned "Little Bird" AH-6 helicopter headed by Boeing (Boeing Rotorcraft Systems). This pilotless aircraft was first-flown on September 8th, 2004 and remains under development for the United States Army as a light attack and reconnaissance helicopter as of this writing (2018). This entry is detailed elsewhere on this site.
The Vietnam War-era OH-6 "Cayuse" light helicopter maintains its own variants listing and is also detailed elsewhere on this site. The MD500 "Defender" has seen production reach 471 units. A first-flight was recorded in 1976 and the type remains in service today (2018). It also has its own lengthy list of variants not covered in this article. The MD600 is a further development of the 500-series and was first-flown in November of 1994. Production has been ongoing since 1995.
The MD500 series helicopters maintain an active presence around the globe - such has been its staying power.
April 2017 - The United States State Department has approved the sale of a dozen MD530F military helicopters to Kenya. These will succeed the elder fleet of MD500 systems currently in service and the deal includes armament fits as well as ammunition.
September 2017 - It was announced that the U.S. Army has committed to the procurement of up to 150 MD500 series helicopters in the "Cayuse Warrior" light armed scout helicopter standard. Some of these will stock the growing fleet of Afghan Air Force helicopters.
October 2018 - Kenya and Lebanon have committed to orders for twelve M530 light scout attack helicopters between them (six and six). Deliveries will take place around mid-2019 and include machine gun and rocket pod weapon systems.
December 2019 - Deliveries of the MD 530G to Malaysia are expected during early-2020.
November 2020 - Finnish Army MD500 helicopters are set to receive an avionics modernization to keep the systems viable for the next few decades.
Afghanistan; Argentina; Canada; Chile; Colombia; Croatia; Ecuador; El Salvador; Finland; Hungary; Iraq; Israel Italy; Japan; Kenya; Lebanon (ordered); Malaysia; Mexico; North Korea; Panama; Philippines; South Korea; Spain; Taiwan; United States
(OPERATORS list includes past, present, and future operators when applicable)
✓Close-Air Support (CAS)
Developed to operate in close proximity to active ground elements by way of a broad array of air-to-ground ordnance and munitions options.
✓Special-Mission: Anti-Submarine Warfare (ASW)
Equipped to search, track, and engage enemy underwater elements by way of specialized onboard equipment and weapons.
✓Special-Mission: MEDical EVACuation (MEDEVAC)
Extraction of wounded combat or civilian elements by way of specialized onboard equipment and available internal volume or external carrying capability.
✓Special-Mission: Search & Rescue (SAR)
Ability to locate and extract personnel from areas of potential harm or peril (i.e. downed airmen in the sea).
Used in roles serving the commercial aviation market, ferrying both passengers and goods over range.
Used in the Very-Important-Person (VIP) passenger transport role, typically with above-average amenities and luxuries as standard.
✓Intelligence-Surveillance-Reconnaissance (ISR), Scout
Surveil ground targets / target areas to assess environmental threat levels, enemy strength, or enemy movement.
Serving Special Forces / Special Operations elements and missions.
Aircraft inherently designed (or later developed) with an unmanned capability to cover a variety of over-battlefield roles.
31.2 ft (9.50 m)
26.2 ft (8.00 m)
8.2 ft (2.50 m)
1,091 lb (495 kg)
2,557 lb (1,160 kg)
+1,466 lb (+665 kg)
(Showcased structural values pertain to the MD Helicopters MD500C (Model 500C) production variant)
1 x Allison 250-C20 turboshaft engine developing 278 horsepower while driving a five-bladed main rotor and two-bladed tail-rotor.
Military models are armed as needed per mission set through rocket pods, gun pods, cannon pods, and miniguns.
(Not all ordnance types may be represented in the showcase above)
MD500 - Base Product Designation
Model 369 - Original prototype model
Model 369A - Production form of Model 369
MD500C (Model 369H) - Five-seat commerical passanger hauler.
MD500 "Defender" - Military Variant; model of 1976; 471 built.
MD500D "Scout Defender" - Armed reconnaissance model
MD500M/ASW - Spanish Navy export model used in the Anti-Submarine Warfare (ASW) role.
MD500M "Defender" (Model 369HM) - Military export variant; model of 1968.
MD530MG "Defender" - Militarized variant of the Model 530F.
MD530 "Nightfox" - Low-light-level attack platform
MD530MG "Paramilitary Defender" - Police variant
MD540F - Modernized Model 530F.
MD500C (Model 369HS) - Model of 1969; four-seat passenger hauler; fitted with Allison 250-C20 engine of 400 horsepower.
MD500C (Model 369HE) - Model 369HS with improved interior finish; model of 1982.
MD500D (Model 369D) - Commercial passenger model of 1976; fitted with Allison 250-C20B engine of 420 horsepower; model of 1976.
MD500E (Model 369E) - VIP passenger model; model of 1982; new nose assembly.
MD530F (Model 369F) - "Hot-and-High" variant; fitted with Allison 250-C30B engine of 650 horsepower; model of 1985.
MD520N ("NOTAR" = "NO Tail ROtor") - Model of 1991; based on the Model 500E.
"Little Bird" UAV - Unmanned technology demonstrator based on the commercial market Model 530F series.
NH-500E - Model 500E produced in Italy by Breda-Nardi (Agusta).
Kawasaki-Hughes Model 369HS - Local Japanese model manufactured by Kawasaki Heavy Industries (KHI).
YOH-6A - U.S. Army evaluation models based on the Model 369.
OH-6 "Cayuse" - U.S. Army production models based on the Model 369A.
Values are derrived from a variety of categories related to the design, overall function, and historical influence of this aircraft in aviation history.
The overall rating takes into account over 60 individual factors related to this aircraft entry.
Rating is out of a possible 100 points.
Relative Maximum Speed
This entry's maximum listed speed (177mph).
Graph average of 150 miles-per-hour.
MD Helicopters MD500C (Model 500C) operational range when compared to distances between major cities (in KM).
Max Altitude Visualization
The three qualities reflected above are altitude, speed, and range.
Aviation Era Span
Showcasing era cross-over of this aircraft design.
Unit Production (4,700)
Compared against Ilyushin IL-2 (military) and Cessna 172 (civilian).
Ribbon graphics not necessarily indicative of actual historical campaign ribbons. Ribbons are clickable to their respective aerial campaigns / operations / aviation periods.
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