As the "Central Military Account on the Cloud", early warning aircraft has become an important part of air forces in many countries and regions around the world.
early warning aircraft is a special aircraft. It has functions such as early warning, command, electronic warfare , air control, etc., and can effectively improve battlefield perception capabilities. It has become a recognized combat power multiplier.
From the end of World War II to the present, early warning aircraft has been developing for nearly 80 years. In its development history, the research and development of almost all early warning aircraft models around the world involves the mutual cooperation between two important systems, aircraft platform and airborne radar system.
E-2C early warning aircraft
special aircraft platform includes a special platform and a general platform. The former is such as the E-2 series early warning aircraft, and the body is specially developed for this type of early warning aircraft; the latter is such as the Boeing 737, etc., which are developed based on the existing aircraft platform and adapted to related special equipment.
However, whether it is a dedicated platform or a general platform, looking at many early warning aircraft that have received praise from the industry around the world, the aircraft development unit is the main line, and the airborne radar and avionics system that meets the development requirements are selected. Through the integrated customization of the airborne system and the aircraft platform, the design optimization is achieved.
During the entire life cycle of the body platform, the airborne radar system will continue to upgrade with the advancement of technology to adapt to the requirements of different periods and users. The work that runs through it is also inseparable from the good coordination and balance between the aircraft platform and the airborne radar system.
Therefore, in the development of early warning aircraft, the lead contractor is generally an aircraft design manufacturer. Only aircraft manufacturers can coordinate various system suppliers, including onboard radar suppliers, integrate resources, and ultimately achieve an excellent early warning aircraft.
E-2 early warning machine is marketed worldwide.
These characteristics are fully reflected in the E-2 series early warning body that once marketed worldwide. The integrated design of
aircraft and early warning equipment
E-2 series early warning aircraft began in 1956. At that time, the US Navy asked Northrop Grumman to develop a carrier-based early warning aircraft for it that can be deployed on the aircraft carrier deck and maximize its detection capabilities.
In order to meet this demand, Nog, the main contractor, designed an E-2 series early warning aircraft after comprehensively considering the indicators and design boundaries between the airborne radar system and the carrier-based aircraft platform at that time.
E-2A early warning aircraft for the first landing test.
E-2 early warning aircraft uses a specially designed body platform. In terms of overall design, Nog Company comprehensively considers the deployment requirements of the aircraft carrier platform, the design parameters of the radar system, the division of labor and composition of the aircraft, and has integrated design of the E-2 layout, weight, stability and even flight attitude.
As a carrier-based early warning aircraft, the weight and size of E-2 are first restricted by the aircraft carrier platform. After all, the catapult and the blocking system can only support aircraft take-off and landing with limited tonnage, and the hangar and elevator have strict restrictions on the length, width and height of the aircraft. These factors first determine the approximate weight and tonnage of the E-2 platform, and then determine how large and heavy the size and weight of the radar can be installed outside the cabin, and how many workstations and corresponding personnel can be carried in the cabin.
E-2D, the design of carrier-based early warning aircraft is strictly restricted by aircraft carrier deployment.
As the most important special equipment for early warning aircraft, the airborne radar system must naturally be selected and adapted within this framework. The empty weight of the
E-2 series is roughly around 14.1 (Type A) to 19.6 (Type D) tons depending on the model, and the maximum take-off weight does not exceed 24.9 (Type A) to 26.1 (Type D) tons.
Under such a maximum take-off weight, the weight margin that the E-2 body can leave to the radar is very small, and the detection distance must be as large as possible; therefore, the radar system adopted by E-2 chooses the largest possible antenna diameter, and has made great concessions in the antenna structure and band . The radome diameter of
E-2 reaches 7.32 meters, forming a 1:3.6 ratio with the wingspan (24.56 meters). If you only consider the deck operation, the E-2's antenna size actually has room for more room than the folding rear wingspan length of 8.94 meters.However, the continued increase in radome will inevitably lead to changes in aerodynamic shape, weight, and center of gravity. These factors will inevitably destroy the maneuverability and stability of the aircraft.
Overall, 7.32 meters is very close to the acceptable limit of flight safety. Therefore, E-2 has very strict angle of attack restrictions during use, and the flight attitude adopts an extremely rare downward tilt attitude.
A very brain-strapped dedicated platform design
In addition to implementing the requirement of aircraft carrier deployment, in order to maximize the early warning function, Nog has also been very brainstorming in the design and development of aircraft platforms.
In addition to conventional modification projects such as weight adjustment, local structure strengthening, hydraulic gas supply and power supply, electromagnetic compatibility testing, etc., the targeted design of E-2 on the carrier platform is mainly reflected in the tail wing.
E-2 early warning machine adopts a rare 4-sided tail design.
In order to avoid interference from the wake of the radar cover, and to block the radar wave's emission direction, and to try to facilitate the work of the radar system, E-2 adopts a special 4-sided tail design to reduce the height of the vertical tail while ensuring sufficient vertical tail area.
At the same time, the E-2's vertical tail also uses as much wave-transmissive fiberglass material as possible, and uses a complex dual-axis design on the three rudders - this allows the E-2 to better maintain the fuselage level when turning, which is conducive to radar detection.
aircraft continuously iteratively updates
Design classic fuselage platforms can often serve for decades or even half a century, but the progress of systems such as airborne radar and avionics is changing with each passing day. Therefore, a good early warning aircraft product is often used to continuously upgrade the airborne radar system on a stable body platform to achieve the goal of serial development.
E-2 series early warning aircraft is no exception.
The early E-2A/B radars used parabolic antenna , while the E-2C model developed later adopted Yagi antenna with a longer working wavelength (0.68~0.75 meters). Yagi antenna has a mass of about 772 kilograms, and the weight with the entire radome is only 2 tons.
Currently the latest E-2D, the main structure of radar antenna is still based on Yagi's enhanced design.
In addition, due to size limitations, the E-2 early warning aircraft is significantly weaker in its important capabilities such as detection accuracy, reliability, and coping with complex terrain environments than the E-3 models of the same period. Only technological progress can achieve a leapfrog improvement in volume, weight and accuracy of the airborne radar system.
It was not until 1992 that the E-2C realized the pulse Doppler function after being equipped with the AN/APS-145 radar, and had reliable downward vision detection capabilities for complex terrain environments.
E-2C early warning machine. The E-2 aircraft, which was first flew in 1960, is still in service today. Over the years, the basic design of the body platform designed by Nog has never changed, and the airborne radar system has undergone four major changes - through continuous updates of equipment, E-2D is still the world's most advanced small early warning aircraft, and it is an irreplaceable role in the field of carrier-based early warning aircraft.
E-2D early warning machine .
New trends in future early warning system
At the beginning of the E-2 design, under normal circumstances, except for the two drivers, the E-2 can only carry three workstations and corresponding mission operators, responsible for radar operation, air control and combat command respectively. Such a limited number of equipment and personnel also greatly limits the E-2's task processing capabilities, especially complex command and control tasks.
E-2A/B cabin.
In order to reduce weight and resistance, the E-2 fuselage diameter is small, the movement range of staff is very narrow, and the strong noise and vibration in the cabin are not subject to any restraint measures. The harsh working environment of
also causes the E-2 crew to be exhausted after several hours of flight and their ability to perform tasks has dropped significantly. Therefore, when performing continuous missions, a single aircraft is usually equipped with 2 to 3 units to carry out shift flights.
The effective time of the unit's work has in turn affected the improvement space of E-2.
Due to the small tonnage of E-2, the range and air stagnation time (4.4 hours from 320 kilometers away from the aircraft carrier) are relatively limited, but the US Navy has not considered adding air refueling capabilities to the E-2 for a long time. The reason is that this is the big reason: the longer single flight time, although the aircraft can hold on, the crew performing the mission can no longer hold on.
E-2C cabin.
When the US Navy added air refueling capabilities to E-2D in the later period, the focus of the inspection and testing was whether its crew could last 8.5 to 9 hours of flight time.
In addition, with the continuous advancement of radar and electronic technology, the operators of E-2 series aircraft have also achieved expansion - especially, this expansion is not just in the cabin. One of the important improvements in the later stage of
E-2 is to use the advancement of electronic equipment to allow a driver to act as the fourth operator through the glass cockpit and high-speed data link.
At the same time, the aircraft carrier ground personnel perform remote operations in the rear, acting as the fifth, sixth, and even seventh mission operators.
E-2D is equipped with AN/APY-9 radar, and the cockpit has also been improved to a glass cockpit. Changes like
may indicate a trend: in the future, based on the development of electronic technology, remote, intelligent and even unmanned early warning aircraft will become an important part of the future air early warning system, and mission operators are not on the early warning aircraft just the beginning.
In recent years, especially after the 1990s, new small and medium-sized early warning aircraft have been continuously emerging, and the seller's advantage of E-2 has been greatly weakened, and the early hot sales scene has been difficult to reproduce.
Now, many countries around the world are developing their own carrier-based early warning aircraft projects. It can be foreseeable that these problems encountered by E-2 in the development of the development of these later projects are more or less unavoidable; but the delicate balance reached between the airborne radar system and the aircraft platform in the development of the E-2 also provides valuable experience for later projects.
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