In the process of creating a nuclear submarine - a carrier of sea-based cruise missiles and special forces groups (SSGNs), into which the first four Ohio-class SSBNs were converted, as well as littoral combat ships (LBK, recently, in accordance with changes in the classification, they became frigates) on On the agenda, the question arose of the need to include in their armament aircraft (AC) capable of promptly providing effective air support for their actions. First of all, it was about conducting all-day and all-weather reconnaissance and observation, issuing target designation and assessing damage inflicted on the enemy, and shock and ensuring the actions of special forces, including the delivery of supplies, were identified as secondary tasks.
At the same time, the small volumes of usable space available on the relatively small LBK, and the features of the combat work of the SSGN did not allow the use of either manned aircraft or large drones of the MQ-8 Fire Scout type for these purposes. The only remaining option is the use of unmanned aerial vehicles (UAVs), capable of launching from the deck of a ship or from the surface of the water (in the latter case, it was possible to withdraw the device from a submarine, followed by a start from the water), as well as to land on the water after completing the task.
In this regard, American military experts proposed to consider the possibility of creating a multi-purpose unmanned aerial vehicle (Multi-Purpose UAV or MPUAV) with a surface / underwater launch, which was primarily supposed to equip the Ohio-class SSGN. The promising UAV was named after one of the most common seabirds - the cormorant, which in transliteration from English sounds more proudly - "Cormorant".
DARPA BEGINS
In 2003, specialists from the Defense Advanced Research Projects Agency (DARPA) began a six-month "zero" stage of this program, within which they conducted a preliminary study of the possibility of creating a UAV capable of independently launching from an underwater or surface carrier, and determining the tactical and technical requirements for it.
The project leader was Dr. Thomas Buettner, who worked in the Agency's Tactical Technology division and also led the Friction Drag Reduction and Oblique Flying Wing programs. Within the framework of these programs, respectively, it was supposed to develop a model for estimating the value of friction resistance in relation to surface ships of the US Navy and develop technical solutions to reduce it (this made it possible to reduce fuel consumption and increase the speed, range and autonomy of navigation of ships), as well as the creation of an experimental model of a high-speed aircraft of the type "Flying wing", the sweep of the wing of which changed due to the "skew" of its planes (one plane was pushed forward (negative sweep), and the other - backward (positive sweep).
According to the official representative of DARPA Zhanna Walker, the promising UAV was intended to "provide close air support for such warships as littoral warships and SSGNs."In accordance with the data of the project card published by DARPA, the program had to solve the following tasks:
- to develop a concept for the use of UAVs with surface and underwater launch;
- to study the behavior of UAVs on the border of water and air;
- to work out in practice new composite materials;
- to ensure the strength and tightness of the UAV structure required when launched from designated depths or from a surface ship;
- to work out the power plant of the UAV, capable of withstanding the aggressive environmental conditions in the underwater area, as well as to demonstrate the ability to quickly start the UAV propulsion engine for launching from the water;
- to work out all the elements of the practical application of UAVs - from starting from a surface and underwater carrier to splashdown and evacuation.
Two years later, the Pentagon approved the transition to the first stage of the program, Phase 1, under which funding for the development, construction and testing of a prototype UAV, as well as funding for work on individual on-board systems, was carried out by DARPA, and the direct development of the device was entrusted to the Skunk Works division of the company. Lockheed Martin . The company also covered part of the project costs.
"The multipurpose UAV will be part of a single unique network-centric system, which will significantly expand the combat capabilities of the new SSGN, created on the basis of the Trident system," the Lockheed Martin press release emphasized. - Possessing the ability to launch underwater and being distinguished by high secrecy of actions, the UAV will be able to operate effectively from under the water, providing the necessary air support. The combination of the Trident system and a multipurpose UAV will provide theater commanders with truly unique opportunities - both in the pre-war period and in the course of full-scale hostilities."
WINGED TRANSFORMER
After studying various ways of placing UAVs on board Ohio-class SSGNs, Skunk Works specialists decided to use "natural launchers" - SLBM missile silos, which had a length (height) of 13 m and a diameter of 2.2 m. with a folded wing - a wing of the "gull" type was attached to the fuselage on hinges and folded, as it were, "hugged" it. After opening the shaft cover, the UAV extended beyond the outer contours of the submarine carrier's hull on a special "saddle", after which it opened the wing (the planes rose to the sides upward at an angle of 120 degrees), freed itself from the grips and, due to positive buoyancy, independently floated to the surface of the water.
Upon reaching the surface of the water, two solid-propellant launch accelerators - modified solid propellant rocket engines of the Mk 135 type used on the Tomahok SLCM - were included in the work. The engines had a running time of 10–12 s. During this time, they lifted the UAV vertically up from the water and brought it to the calculated trajectory, where the main engine was switched on, and the solid propellant rocket motors themselves were dropped. It was planned to use a small-sized by-pass turbojet engine with a thrust of 13.3 kN, based on the Honeywell AS903 engine, as a propulsion engine.
The UAV was planned to be launched from a depth of about 150 feet (46 m), which required the use of high-strength materials in its design. The UAV body is made of titanium, all voids in the structure and docking units were carefully sealed with special materials (silicone sealants and syntactic foams), and the inner space of the fuselage was filled with an inert gas under pressure.
The mass of the apparatus is 4082 kg, the mass of the payload is 454 kg, the mass of JP-5 jet fuel for the main engine is 1135 kg, the length of the apparatus is 5.8 m, the wing span of the "gull" is 4.8 m, and its sweep along the leading edge - 40 degrees. The payload included a mini-radar, an optoelectronic system, communications equipment, as well as small-sized weapons such as a Boeing SDB small-caliber bomb or a small-sized missile launcher with an autonomous guidance system LOCAAS (LOw-Cost Autonomous Attack System) developed Lockheed Martin. The combat radius of the "Cormoran" is about 1100-1300 km, the service ceiling is 10.7 km, the flight duration is 3 hours, the cruising speed is M = 0.5, and the maximum speed is M = 0.8.
In order to increase the secrecy of actions immediately after the launch of the UAV, the carrier submarine had to immediately leave the area, moving as far as possible. After the unmanned aerial vehicle completed the task, a command was sent to it from the submarine to return and the coordinates of the splashdown site. At the designated point, the on-board control system of the UAV turned off the engine, folded the wing and released the parachute, and after splashdown, the Cormoran released a special cable and awaited evacuation.
“The task of safely splashing a 9,000 lb vehicle at a landing speed of 230–240 km / h is a daunting task,” said senior project engineer Robert Ruzkowski at the time. - There were several ways to solve it. One of them consisted in a sharp drop in speed and the implementation of the cobra maneuver pre-laid in the on-board control system, and the other, more realistic from a practical point of view, option consisted in the use of a parachute system, as a result of which the device splashed down nose first. At the same time, it was necessary to ensure the safety of the UAV itself and its equipment in the overload range of 5–10 g, which required the use of a parachute with a dome with a diameter of 4, 5–5, 5 m”.
The docked UAV was detected using sonar, and then it was picked up by a remotely controlled unmanned underwater vehicle. The latter was released from the same missile silo where the "drone" was previously located, and pulled a long cable behind it, which was docked with the cable released by the UAV, and with its help the "drone" was put on the "saddle", which was then removed into the submarine's missile silo.
In the case of the use of "Cormoran" from a surface ship, in particular the LBK, the device was placed on a special sub-boat, with the help of which it was taken overboard. After the UAV splashdown, all actions were repeated in the same sequence as when starting from a submerged position: starting the starting engines, turning on the propulsion engine, flying along a given route, returning and splashing down, after which it was necessary to simply pick up the device and return it to the ship.
WORK WASN'T GOING TO GO
The first stage of work, within which the contractor had to design the apparatus and a number of related systems, as well as demonstrate the possibility of integrating them into a single complex, was designed for 16 months. On May 9, 2005, a corresponding contract worth $ 4.2 million was signed with the Lockheed Martin Aeronotics division, identified as the main contractor for the program. In addition, the number of performers included General Dynamics Electric Boat, Lockheed Martin Perry Technologies and Teledine Turbine Engineering Company, with which the corresponding contracts were signed for a total of $ 2.9 million. The customer himself, DARPA agency, received $ 6.7 million from the US Department of Defense budget for this program in fiscal 2005 and requested an additional $ 9.6 million for fiscal 2006.
The work on the first stage should have resulted in two main tests: underwater tests of a full-size, but non-flying UAV model, which was to be equipped with the main on-board systems, as well as tests of a “saddle” model, on which the device was to be located in the nuclear-powered missile silo (model installed on the seabed). It was also necessary to demonstrate the possibility of a safe landing of the UAV "nose forward" and the ability of its onboard equipment to withstand the resulting overloads. In addition, the developer had to demonstrate the evacuation of a mock-down UAV using a remotely controlled unmanned underwater vehicle and demonstrate the possibility of ensuring the launch of a two-circuit turbojet sustainer by supplying high-pressure gas.
Based on the results of the first stage, the leadership of DARPA and the Pentagon had to make a decision on the further fate of the program, although already in 2005, DARPA representatives announced that they expect the Cormoran UAVs to enter service with the US Navy in 2010 - after the completion of Phase 3.
The first stage of testing was completed by September 2006 (demonstration tests were carried out in the area of the base of the US Navy's submarine forces Kitsap-Bangor), after which the customer had to make a decision on financing the construction of a full-fledged flight prototype. However, in 2008, the DARPA management finally stopped funding the project. The official reason is budget cuts and the choice of Boeing's Scan Eagle as the "underwater" UAV. However, while submarines with cruise missiles of the Ohio type and the special forces groups of the US Navy based on them remain without UAVs with an underwater launch, and littoral warships, which have become frigates, can only use larger unmanned aerial vehicles of the Fire Scout type and more simple mini-class drones.
