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de Havilland DH.117

Mach 2 High-Altitude Interceptor Proposal

de Havilland DH.117

Mach 2 High-Altitude Interceptor Proposal

OVERVIEW
SPECIFICATIONS
ARMAMENT
VARIANTS
HISTORY
MEDIA
OVERVIEW



A single mock-up was the only concrete evidence of the proposed de Havilland DH.117 interceptor intended for Britain before all was said and done.
National Flag Graphic
ORIGIN: United Kingdom
YEAR: 1958
STATUS: Cancelled
MANUFACTURER(S): de Havilland Aircraft - UK
PRODUCTION: 0
OPERATORS: United Kingdom (cancelled)
SPECIFICATIONS



Unless otherwise noted the presented statistics below pertain to the de Havilland DH.117 model. Common measurements, and their respective conversions, are shown when possible.
CREW: 2
LENGTH: 66.77 feet (20.35 meters)
WIDTH: 38.06 feet (11.6 meters)
WEIGHT (MTOW): 55,116 pounds (25,000 kilograms)
ENGINE: 2 x de Havilland Gyron Junior afterburning (reheat) turbojet engines developing 12,000lb of thrust with 1 x Spectre Spe.5 rocket booster developing 10,000lb of additional thrust.
SPEED (MAX): 1,802 miles-per-hour (2900 kilometers-per-hour; 1,566 knots)
RANGE: 621 miles (1,000 kilometers; 540 nautical miles)
CEILING: 60,039 feet (18,300 meters; 11.37 miles)
RATE-OF-CLIMB: 36,800 feet-per-minute (11,217 meters-per-minute)
ARMAMENT



PROPOSED:
2 x Underwing hardpoints (one per wing) for the carrying of Blue Jay Mk.4 (Blue Vesta) air-to-air missiles (AAMs).
Graphical image of an air-to-air missile weapon
Graphical image of a short-range air-to-air missile
VARIANTS



Series Model Variants
• DH.117 - Base Project Designation.


HISTORY



Detailing the development and operational history of the de Havilland DH.117 Mach 2 High-Altitude Interceptor Proposal.  Entry last updated on 3/19/2019. Authored by Staff Writer. Content ©www.MilitaryFactory.com.
During the time of the Cold War (1947-1991) between East and West, British military power was to figure heavily into the defense of Western Europe should a Soviet invasion ever occur. This meant that its various service branches required all manner of modern technology to meet the threat of the day - namely that from nuclear-capable Soviet bombers.

Many aircraft designs were drawn up during the period to meet various demands: fleet air defense, day-night fighter, high-speed / high-altitude interceptor and so on. By the time of the mid-1950s, serious thought was being given by British authorities to shore up interception capabilities, particularly at high-altitude. This resulted in design studies and a formal requirement being penciled out by the latter part of the decades.

It was requested that a new, all-modern interceptor be developed that carried radar as well as strictly Air-to-Air Missile (AAM) armament controlled by an all-in-one weapon system. To go along with this, three critical factors came into play for Cold War-era interceptors: rate-of-climb, speed, and altitude. As such, a twin-engine (reheat-capable) design was all but necessary augmented by a limited-burn rocket booster unit. This would provide the aircraft with a quick take-off capability, reaching the desired interception altitude, while then achieving Mach 2 speeds to reach the target area. Once in range of radar, attack would commence with beam-riding missiles. To offset the expected onboard workload (now involving piloting, weapons management, and radar management), a crew of two was a must. In turn, this required a pressurized cockpit as well as ejection seats.

Authorities called for a finalized design no later than January 1962, which placed expediency at the forefront above all else.

de Havilland engineers attempted to meet the requirement through their DH.117 submission. It was, rather optimistically, intended that the aircraft could see its first-flight before the end of 1958 and Initial Operational Capability (IOC) could be reached within the intended 1962 timeframe. Up to four flyable aircraft would be constructed for the prototyping and flight-testing phases followed by production-quality units to take into active service.

While the official requirement called for a maximum speed in the vicinity of Mach 2, engineers saw their sleek aircraft flying in excess of Mach 2.3 and was also marketed with a service ceiling of 60,000 feet. Range would be augmented by the addition of wing tip fuel tanks to bolster the already-onboard fuel stores while under full war load. Due to the high speed involved, titanium would factor into the aircraft's overall construction to go along with lightweight, yet strong, alloys.

The DH.177, as proposed, incorporated tapered, straight-edged wing mainplanes low-mounted at midships along the fuselage sides. The mainplanes, made as slim as possible for limited drag, were given noticeable anhedral (downward angle) and were capped by the wing tip tanks. Each member would also feature a single underwing hardpoint to carry an AAM (at this point the "Blue Jay" series was in focus). The cockpit would seat its two crew in tandem aft of the long and slender nosecone housing the radar unit. The fuselage, also long and slender, tapered to a point under the single vertical tail fin. Along the midway span of the rudder were installed the horizontal tailplanes.

The engines were to be housed in nacelles formed into the lower fuselage sides, aspirated via semi-circular ports near the cockpit walls and exhausted through circular ports ahead of the tail unit. To benefit climb and straightline performance, a Spectre Spe.5 booster rocket of 11,000lb thrust was to be embedded into the ventral line of the fuselage. The engines-of-choice became de Havilland's own Gyron Junior afterning turbojets of 12,000lb thrust. Maximum estimated speed was officially Mach 2.35 at altitude.

As drawn up, the DH.117 had an overall length of 68.9 feet with a wingspan of 38 feet. Gross weight was 55,000lb.

Despite the British need and promising scope of the de Havilland proposal, the DH.117 was not to be. A mock-up was completed by de Havilland but little else was had for the project. It went on to join many other abandoned interceptor forms of the period as requirements changed and technology progressed.




MEDIA







Our Data Modules allow for quick visual reference when comparing a single entry against contemporary designs. Areas covered include general ratings, speed assessments, and relative ranges based on distances between major cities.

Image of collection of graph types

Relative Maximum Speed Rating
Hi: 1900mph
Lo: 950mph
    This entry's maximum listed speed (1,802mph).

    Graph average of 1425 miles-per-hour.
City-to-City Ranges
NYC
 
  LDN
LDN
 
  PAR
PAR
 
  BER
BER
 
  MSK
MSK
 
  TKY
TKY
 
  SYD
SYD
 
  LAX
LAX
 
  NYC
Graph showcases the de Havilland DH.117's operational range (on internal fuel) when compared to distances between major cities.
Aviation Era
Pie graph section
Pie graph section
Pie graph section
Pie graph section
Pie graph section
Useful in showcasing the era cross-over of particular aircraft/aerospace designs.
Unit Production Comparison
Comm. Market HI*: 44,000 units
Military Market HI**: 36,183 units
0
0

  * Commercial Market High belongs to Cessna 172.

  ** Military Market High belongs to Ilyushin Il-2.


Altitude Visualization
Small airplane graphic
Supported Roles
A2A
Interception
UAV
Ground Attack
CAS
Training
ASW
Anti-Ship
AEW
MEDEVAC
EW
Maritime/Navy
SAR
Aerial Tanker
Utility/Transport
VIP
Passenger
Business
Recon
SPECOPS
X-Plane/Development
A2A=Air-to-Air; UAV=Unmanned; CAS=Close Support; ASW=Anti-Submarine; AEW=Airborne Early Warning; MEDEVAC=Medical Evac; EW=Electronic Warfare; SAR=Search-Rescue
Commitments / Honors
Military lapel ribbon for Operation Allied Force
Military lapel ribbon for the Arab-Israeli War
Military lapel ribbon for the Battle of Britain
Military lapel ribbon for the Battle of Midway
Military lapel ribbon for the Berlin Airlift
Military lapel ribbon for the Chaco War
Military lapel ribbon for the Cold War
Military lapel ribbon for the Cuban Missile Crisis
Military lapel ribbon for pioneering aircraft
Military lapel ribbon for the Falklands War
Military lapel ribbon for the French-Indochina War
Military lapel ribbon for the Golden Age of Flight
Military lapel ribbon for the 1991 Gulf War
Military lapel ribbon for the Indo-Pak Wars
Military lapel ribbon for the Iran-Iraq War
Military lapel ribbon for the Korean War
Military lapel ribbon for the 1982 Lebanon War
Military lapel ribbon for the Malayan Emergency
Military lapel ribbon representing modern aircraft
Military lapel ribbon for the attack on Pearl Harbor
Military lapel ribbon for the Six Day War
Military lapel ribbon for the Soviet-Afghan War
Military lapel ribbon for the Spanish Civil War
Military lapel ribbon for the Suez Crisis
Military lapel ribbon for the Vietnam War
Military lapel ribbon for Warsaw Pact of the Cold War-era
Military lapel ribbon for the WASP (WW2)
Military lapel ribbon for the World War 1
Military lapel ribbon for the World War 2
Military lapel ribbon for the Yom Kippur War
Military lapel ribbon for experimental x-plane aircraft
* Ribbons not necessarily indicative of actual historical campaign ribbons. Ribbons are clickable to their respective campaigns/operations.


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