Newbury Park's unrealized multirole UAV: the Northrop Ventura NV-131

In 1975 the US Air Force was trying to figure out what the capabilities of the next generation of unmanned air vehicles should be and how such a vehicle would accomplish these objectives. Although the USAF's existing inventory of remotely piloted vehicles (RPVs) was being continually improved, it still utilized the airframe of the prolific Firebee drone family. Therefore, Tactical Air Command's primary effort focused on a multirole RPV to address the extreme combat environment expected in the European theater of the Cold War. In April 1975, the US Air Force issued a one-year fixed-price study contract to three companies (Boeing, Northrop, and Rockwell International) to design an Advanced Remotely Piloted Vehicle (ARPV) for service in the 1980s. The UAV design envisioned under the ARPV program would be capable of carrying out a variety of roles, such as reconnaissance, electronic warfare, and strike missions, and it was intended to replace the upcoming Teledyne Ryan BGM-34C multirole derivative of the Firebee. By early 1976 Boeing, Northrop Ventura, and Rockwell had come up with ARPV designs utilizing different launch/recovery methods. 

Quarter-scale model of the Northrop Ventura NV-131 multi-role UAV

The design conceived by Northrop's Ventura Division for the ARPV program was designated NV-131. It featured a cigar-shaped airframe with a pointed nose, and it had high-mounted straight wings along with a vertical stabilizer near the mid-section of the fuselage. It was 30 feet (9.14 meters) long with a wingspan of 15 feet (4.57 meters), and power was to be supplied by one General Electric J85 turbojet housed in the rear fuselage and fed by air flowing into an air intake atop the rear fuselage. The NV-131 was designed to be launched from either a catapult or a RATO zero-length launcher, and it would be recovered by an arrester cable or hook. When configured for combat missions, the NV-131 could carry weapons on external underwing hardpoints, and as a reconnaissance or electronic warfare vehicle it was to house an internal payload (cameras or electronic warfare equipment) in the fuselage.

Despite having promised to field an all-new multirole UAV, the ARPV program was canceled by the late 1970s before the NV-131 or any other proposal for the ARPV program could be down-selected for full-scale development. This was probably due to the fact that Tactical Air Command saw manned tactical combat aircraft as offering more ability to take on the Soviet electronic warfare, integrated air defense, and manned aircraft threats in Central Europe than UAVs.

References:

Klass, P.J., 1976. "Increased Use of Mini-RPVs Seen." Aviation Week & Space Technology 104 (20) (17 May 1976): 58-61.

Taylor, J.W.R., 1976. Jane's All the World's Aircraft 1976-1977. London, UK: Jane's Yearbooks.

Convair's forgotten carrier-based Sea Dart

The Convair F2Y Sea Dart is remembered as the only jet-powered seaplane fighter ever built for the US Navy, combining a pure delta wing and supersonic performance with sea-based takeoff and landing characteristics. Even as development and testing of the Sea Dart got underway, Convair looked at several evolutionary developments of this aircraft, including single-engine proposals and a Sea Dart designed for operations from submarines. Recently, while surfing the Secret Projects Forum, it came to my attention that Convair worked on a derivative of the F2Y for use aboard Navy aircraft carriers around the same time that US aircraft manufacturers were submitting proposals for the Navy's OS-130 requirement. Therefore, this post will discuss Convair's obscure proposal to turn the F2Y into a carrier-based fighter plane.

Three-view drawing of the Convair Carrier Based F2Y proposal (dated January 29, 1953)

On January 29, 1953, four months after the OS-130 requirement was issued, Convair unveiled a proposal called the "Carrier Based F2Y". Like the F2Y-1, it was powered by two Westinghouse J46 turbojets and had a vertical stabilizer that was squared-off at the top. However, the Carrier Based F2Y differed in having folding wingtips, complete wing and tail assemblies moved aft by 30 inches and the engine and nacelle section moved forward 35 inches with relation to the F2Y-1, a curved lower fuselage, and the addition of the tricycle landing gear and arrestor hook. It was 43 feet (13.11 meters) long with a wingspan of 33 feet 11 in (10.34 meters), a wing area of 563 ft2 (52.36 m2), and a gross weight of 23,874 lb (10,829 kg). Armament was to consist of either four 20 mm or three T160 guns, or two batches of 28.2 in (5.1 cm) FFAR unguided air-to-air rockets housed on both sides of the fuselage. The irony surrounding the Carrier Based F2Y project is that the F2Y had been ordered in 1951 due to Navy skepticism over the operation of supersonic aircraft from aircraft carriers, and hence the Carrier Based F2Y was meant to fulfill OS-130 requirements. There is no evidence, however, that this proposal was ever submitted for the OS-130 competition.

Not surprisingly, the carrier-based derivative of the F2Y Sea Dart never saw the light of day because the Navy declared the Vought F8U Crusader the winner of the OS-130 competition. Nevertheless, it might have been designated "F3Y" had it been ordered by the Navy as back-up to the F8U Crusader or F11F Tiger.

References:

Bradley, R., 2013. Convair Advanced Designs II: Secret Fighters, Attack Aircraft, and Unique Concepts 1929-1973.. Manchester, UK: Crécy Publishing.

Buttler, T., 2026. American Secret Projects 5: Fighters and Interceptors 1950 to 1980. Manchester, UK: Crécy Publishing.

The North American D-85: an F-93 for the Navy

In May 1948 the US Navy's Bureau of Aeronautics issued the OS-113 requirement for an interceptor fighter capable of achieving 691 miles per hour (1,110 km/h) in level flight and reaching 50,000 feet (15,240 km) in just six minutes, as well as being able to achieve controlled diving flight at supersonic speeds at both medium and high altitudes. Seven companies -- Douglas (El Segundo), Grumman, Lockheed, McDonnell, North American, Republic, and Vought -- submitted bids for the OS-113 specification, a handful equipped with auxiliary rocket propulsion.

Left: Three-view drawing of the North American D-85
Right: D-85 interior arrangement

North American's design for OS-113 was given the company designation D-85. It drew heavily upon experience gained by North American in design of the YF-93 penetration fighter, featuring a pair of scoop-style side intakes, and power was provided by one Westinghouse J40-WE-8 turbojet as well as one 1,500 lb (6.7 kN) thrust RMI A600C4 rocket motor. The D-85 was 51 feet 6 in (15.70 meters) long with a wingspan of 40 feet 6 in (12.34 meters) (23 feet 8 in [7.21 meters] when folded), a wing area of 425.92 ft2 (39.61 m2), a gross weight of 20,823 lb (9,445 kg), and a top speed of 632 miles per hour (1,017 km/h). When using the jet engine only, the D-85 could reach a top speed of 637 miles per hour (1,025 km/h) and had a gross weight of 19,993 lb (9,069 kg).

The rocket motor of the D-85 was primarily designed for the climb from 35,000 feet (10,668 meters) to 50,000 feet (15,240 meters), and when used in level flight, the D-85 could achieve 668 miles per hour (1,075 km/h) in a dive at the operational altitude. Armament for the D-85 comprised 24 unguided air-to-air rockets housed in a streamlined lower fuselage package placed roughly level with the wing root trailing edge. The pilot could select how many rockets to fire, and the complete firing cycle would take about 1.5 seconds, and like other OS-113 submissions, the D-85 could fire all its rockets within half a second.

In late 1948, the McDonnell Model 58 was selected over other proposals (including the D-85) and ordered into full-scale development as the XF3H-1.

References:

Buttler, T., 2013. Early US Jet Fighters: Proposals, Projects, and Prototypes. Manchester, UK: Hikoki Publications. 

A Skyray for the US Air Force: the Douglas D-614

In a previous post, I mentioned that the Santa Monica division of Douglas submitted the Model 1245 design for the MX-1554 competition, which ended up being won the Convair F-102 and Republic XF-103. Recently, however, it has come to my attention thanks to research by Jared Zichek that the Douglas El Segundo division worked on its own design for the MX-1554 requirement, designated D-614 by Douglas. Therefore, I am dedicating this post to the hitherto-unknown D-614 project.

Three-view drawing of the Douglas D-614 derivative of the F4D Skyray (Frank Simons collection via RetroMechanix)

The design of the D-614 was basically similar to that of the F4D Skyray in its wing planform and in lacking any horizontal stabilizers, but it differed in having a longer nose to house the interception radar and in having a slightly taller vertical stabilizer while lacking the catapult hooks of the Skyray. It measured 50 feet 8 in (15.44 meters) in length with a wingspan of 33 feet 6 in (10.21 meters) and a height of 15 feet 2 in (4.62 meters), and it had an empty weight of 14,109 lb (6,400 kg) and gross weight of 19,740 lb (8,954 kg) along with a wing area of 557 ft² (51.7 m²). Power was supplied by one 15,000 lb (67 kN) thrust Wright J67-W-1 afterburning turbojet, and armament comprised four to six underwing rocket canisters each containing six 2.75 in (7 cm) folding-fin unguided air-to-air rockets.

Like the Model 1245, the D-614 did not make the cut in the MX-1554 competition, and the Douglas El Segundo division was free to concentrate its fighter-related business on production of the F4D as well as development of the F5D Skylancer.

Hawthorne's lost Mohawk: the Northrop N-180

In the mid-1950s the US Army and US Marine Corps published a post-Korean War assessment discussing the vulnerabilities of their existing light observation aircraft, namely the L-19/OE Bird Dog, during that conflict. With this in mind, on behalf of the US Navy the two services initiated the TS-145 requirement for a two-seat, twin-turboprop light observation aircraft to operate from small, unimproved airfields under all weather conditions. The observation aircraft specified by TS-145 had to be faster and utilize greater firepower and heavier armor than the Bird Dog in order to address the vulnerabilities that the Bird Dog had faced during the Korean War.

Three-view drawing of the Northrop N-180 from the Northrop company documents.

Northrop's proposal for the TS-145 requirement was designated N-180 by the company. It was a twin turboprop design measuring 46 feet 1 in (14.05 meters) long with a wingspan of 44 feet 6 in (13.56 meters), and it featured a large cockpit placed ahead of the propeller arcs whereby the pilot and observer sat side-by-side. Power was provided by two General Electric T58-GE-4 turboprops each generating 1,020 shp (750 kW) (the Lycoming T53 was investigated as an alternate engine option for the N-180). The engine nacelles were mounted on the lower surface of the gull wing at the break where the wings levelled out. Missions to be carried out by the N-180 included day and night observation, artillery spotting, forward-position resupply with wing-mounted 750-lb packs, and liaison duties. The N-180 would have a service ceiling of 38,200 feet (11,643 meters) and a top speed of 299 mph (481 km/h) at an altitude of 5,000 feet (1,524 meters), and 150-gallon drop tanks and up to four smoke rockets for target marking would be carried below three hardpoints under each outer wing section. 

The OV-1 Mohawk, the winner of the TS-152 competition.

In November 1956, Northrop submitted the N-180 design, but it lost the TS-145 competition to the rival Grumman G-134 design. The winning G-134 design became the AO-1/OV-1 Mohawk, and even though the Navy withdrew from the OV-1 program, the Army pressed ahead with it. The Mohawk would go on to have a long and very useful career, especially during the Vietnam War.

References:

Chong, T., 2016. Flying Wings & Radical Things: Northrop's Secret Aerospace Projects & Concepts 1939-1994. Forest Lake, MN: Specialty Press.

Northrop N-55: the tailless patroller from Hawthorne

In late 1948, the US Air Force concluded that its ability to defend the continental US from airstrikes was inadequate. Thus, it promulgated an across-the-board scheme to improve American air defense systems, which partly led to the WS-201 (aka 1954 Interceptor) requirement that resulted in development of the delta-winged Convair F-102 Delta Dagger and F-106 Delta Dart as well as the trisonic Republic XF-103 Thunderwarrior. After becoming aware of this situation, the Northrop company proposed an all-wing patrol plane under the designation N-55. The wingspan of the N-55 would be same as that the B-35 and B-49, but the fuselage design would mirror that of the N-31 flying wing bomber project in utilizing fore and aft crew nacelle extensions, giving the plane a length of 61.8 feet (18.8 meters). The N-55 concept was basically not just intended for long-range patrol missions but also would serve to function as an airborne radar picket ship that could fire air-to-air missiles against enemy planes that intruded into North American airspace. Search radars operating in the X-band or S-band ranges would be internally accommodated in the nose and tail of the N-55. 

Northrop N-55 sans suffixe (left) and N-55A (right) design studies for a long-range patrol flying wing

Two N-55 variants were studied. The baseline N-55 design was powered by two Northrop XT37-NA-3 turboprops each delivering 10,000 hp, and it was armed with 44 AAM-N-2 (later GAR-1/2/3/4/5/6/9 and finally AIM-4) Falcon air-to-air missiles (of which a dozen would be fired from leading edge tubes with eyelid covers, the rest being housed in two weapons bays). The N-55A had the same wingspan but was powered by six Westinghouse J40 turbojets. The turboprop-powered N-55 looked like a cross between the baseline N-31 and later N-31A versions because it had two T37 turboprop engines and a pair of vertical stabilizers, while the engine arrangement of the N-55A resembled that of the YB-49, with the jet engines buried between two pairs of vertical stabilizers on the wing's trailing edge.

References:

Chong, T., 2016. Flying Wings & Radical Things: Northrop's Secret Aerospace Projects & Concepts 1939-1994. Forest Lake, MN: Specialty Press.

The new and improved B-49: the Northrop N-40

In 1948 Northrop began to undertake design work on an improved version of the YB-49 prototype flying wing jet bomber, bearing the mind the fact that the YB-49 had some serious deficiencies in operating range and payload capability. For example, the YB-49's operating range was more or less on par with that of the B-47 Stratojet, and its bomb bay was not big enough to carry free-fall nuclear bombs. On August 23, 1948, the US Air Force, seeing that it needed a second flying example of the B-49 bomber, modified the recently signed contract for 30 RB-49s with an amendment to convert one of the RB-49s into a B-49.

Three-view drawing of the Northrop N-40 with six Westinghouse J40 turbojets from the Northrop company documents. 

Northrop's proposal for improvising the YB-49 design was given the company designation N-40. It would have the same airframe as the YB-49 but feature a new center bomb bay in the crew nacelle that measured 170 inches in length, 80 inches wide, and 80 inches deep, big enough to carry America's large-diameter nuclear weapons. To improve bombing accuracy, the N-40 utilized an AN/APQ-24 bombing/navigation system on the lower aft portion of the crew nacelle, and a Minneapolis-Honeywell E-7 autopilot system was incorporated into the design to ameliorate the phugoid oscillations noticed during flight tests of the YB-49. Twin and quad 0.50 caliber machine gun turrets were considered for installation, and one design iteration had one remotely controlled turret below the starboard nose area outboard of the bombardier's glass and one remotely controlled turret in the aft upper fuselage, both with four 0.50 caliber machine guns. The baseline N-40 design had eight 4.850 lb (21.57 kN) thrust General Electric J47-GE-3 turbojets, six buried in the wing and two in pods below the wings. Northrop also looked an N-40 design with six wing-embedded 7,500 lb (33,36 kN) thrust Westinghouse J40 turbojets, and an option to fit the N-40 with six 6,250 lb (27.8 kN) thrust Pratt & Whitney J48s (license-built version of the Rolls-Royce Tay turbojet) was also considered. Another alternate engine provision explored for the N-40 involved the use of two Turbodyne T37 turboprops in conjunction with two or four J40s, similar to the powerplant arrangement planned for the Northrop N-37B (RB-49C).

Although Northrop hoped that the N-40 would entice the US Air Force to order more examples of the B-49, the N-40's life was destined to be short-lived. The cancellation of the RB-49 contract in January 1949 put any thought of clearing the N-40 for full-scale development to rest, and the N-40 was not proceeded with. Given that the N-40 would have had potentially greater range than the YB-49 and the ability to carry free-fall nuclear bombs, it might have been a serious competitor to the B-52 had it been built. 

References:

Chong, T., 2016. Flying Wings & Radical Things: Northrop's Secret Aerospace Projects & Concepts 1939-1994. Forest Lake, MN: Specialty Press.