F-35. Money Slayer or Serious Weapon?
A detailed description of the design and flight control of the Lightning fighter will be available in the next issues of Modelist-Konstruktor for 2021. There, in the Electronics for Beginners application, a diagram of the assembly of the APG-81 radar from 1676 transmit-receive modules will appear. And the recollections of the pilots will clarify the details of the combat use of the F-35, which has received the most controversial assessments since its inception.
Today we cannot trust the numbers that are among the most sensitive characteristics of the Lightning. Such as its visibility for domestic detection means or the declared capabilities of the APG-81 radar. Such details are classified and inaccessible to the general public.
By external signs, it is impossible to determine the exact flight characteristics, but it is possible to understand what techniques are used in the design of the "Lightning", what advantages and disadvantages follow from this, based on examples of 4th generation fighters, in the design of which there were similar elements.
The purpose of this material is to systematize the most reliable facts about the Lockheed Martin F-35 Lightning II fighter.
Distinctive features of the 5th generation
The public and experts attach a lot of importance to cruising supersonic and fantasize about the importance of EPR in Russian and American fighters. Forgetting pay attention to the key.
Domestic and foreign fighters of the 5th generation use a diamond-shaped (trapezoidal) wing.
Here, high bearing properties at subsonic speeds are combined with high wing rigidity. Load-bearing properties are directly related to maneuverability. The paramount quality of the fighter. A rigid wing of low aspect ratio is a sign of a strike aircraft. For throwing towards a target with full combat load and escape at supersonic speed from a retaliatory strike.
According to experts from aviation, the reception with a diamond-shaped wing made it possible to agree on mutually exclusive requirements for the design of fighters and bombers. This is a significant part of the value of the 5th generation.
Considering that fighters and aircraft based on them (Su-34, F-15E) are regularly involved in strike missions, one can understand the reasons for the growing interest associated with the new wing. Which allows continuous flight at transonic (supersonic) speeds. In the absence of tendencies to the emergence of strong vibrations at high speed and low altitudes - an unavoidable property of all fighters of past generations. Whose aerodynamic appearance has been optimized for maneuvering at speeds well below Mach XNUMX.
Planning bombs GBU-39 in the weapons bay of the F-22 fighter
Development of a new class of aircraft capable of effectively attacking ground targets while maintaining the full potential of a fighter in air combat. Fighter and strike squadron pilots can receive a variety of training. The main message is strike and fighter groups, consisting of aircraft with the same flight characteristics and identical design, incl. sighting complexes (more on this below). The organizational advantages of such an Air Force structure are beyond doubt.
All of the above has a direct bearing on the F-35 multirole fighter.
Analysis of external parts
A) The absence of sagging in the root of the wing.
One of the important innovations that influenced the development of the 4th generation was the creation of vortexes to improve the efficiency of aerodynamic controls.
American fighters of the 5th generation are deprived of the "sharp" influx-vortex generators inherent in the F-16 or the Su-27 family. They also lack elements similar to the upper lip of the F-15 Eagle air intakes, which serves the same purpose.
But the Raptors and Lightnings did not abandon the very physical effect of vortex aerodynamics, which provided such a high maneuverability to their predecessors.
In the pictures, it is noticeable that the edge of the air intake is responsible for creating vortices in the F-35.
B) The presence of two V-shaped keels.
With this arrangement, the vertical tail does not fall into the aerodynamic "shadow" of the wing. That allows you to maintain controllability and return the fighter from high angles of attack.
The single keel was considered the biggest drawback of its predecessor, the multipurpose and ubiquitous F-16. According to some reports, he lost track stability and the ability to steer at angles of attack a little more than 10 degrees. And projects of deep modernization of the F-16 began with a proposal to equip the Falcon with two inclined keels.
Single-keel "Rafali", "Gripen" and "Eurofighter" are not affected by this problem, because use other aerodynamic configurations of a glider with a forward horizontal tail.
In the presence of a normal aerodynamic design and a single keel, the F-16 was and remains the worst among the representatives of the 4th generation in terms of handling at high angles of attack. That, however, did not prevent him from becoming a "working tool" in all conflicts.
Like the Falcon, the F-35 has a normal aerodynamic design. The presence of a V-shaped tail means that this fighter got rid of the shortcoming of its predecessor.
For this reason, the F-35 cannot be inferior in maneuverability to the aforementioned F-16. Contrary to popular beliefs, the Lightning is completely helpless in close combat against Generation 4 fighters.
Shots showing flights at critical and supercritical angles of attack. In fact, back forward. Of course, this is not a super-maneuverable Su-35, but you should not ignore the capabilities of an American fighter.
C) Continuing the external examination of the F-35 airframe, we can note the presence of a single engine located near the center of mass. And a noticeable reduction in the size of the bow, due to the installation of a compact airborne radar with AFAR.
The impact of these aspects on flight performance and maneuverability can only be assessed as “positive”.
D) Like all representatives of the 5th generation, the Lightning has a high degree of integration of the wing and fuselage. Yes, we are talking about an integral layout.
The "area rule" unknown to the general public and the fruitless debate about the boundaries of the concept itself (which layout of the F-15 and F-16 is semi-integral or non-integral?) Will be left for another case.
We will focus on the most neutral definition. In the presence of an integral layout, each element has such a strong influence on other elements that it is impossible to consider them in isolation from each other during calculations.
The "Lightning" has an oversized wide fuselage with "clean" surfaces, where it is impossible to draw a clear boundary between the wing and the fuselage. Integral layout signs.
In conclusion, the following remark will sound. Integral layout is definitely a positive quality that improves the flight characteristics of fighters.
E) The F-35 fuselage is oversized in the center section. The emergence of "extra" volumes was associated with the need to place weapons bays and get an increased supply of fuel. In the version with vertical takeoff (F-35B), part of these volumes are used to install a lifting fan.
Allegations about the negative impact of the wide fuselage on the speed of the Lightning do not inspire much confidence. The main source of resistance in flight was and remains the wing. Tens of square meters set at an angle to the airflow. The fuselage's contribution to drag is negligible.
One paradoxical fact confirms this thesis. All speed records of the early 1930s belonged to flying boats - with huge ugly floats. The reduced wing and the increased landing speed forced to land on the water. And from the point of view of air resistance, the effect of reducing the wing area surpassed all other, not the most pleasant changes in the appearance of record-breaking aircraft.
There are no clear signs of inferiority in the appearance of the modern Lightning. As well as evidence of any outstanding performance characteristics. Normal aerodynamic design and engine without OVT. A new type of multi-role fighter for the United States and NATO countries, in which the main shortcomings of its predecessors were eliminated.
We will leave the calculations of the roll rate at various angles of attack to the specialists of the aviation industry. The author listed the obvious things, from which it follows that the F-35 uses a traditional set of techniques and design solutions. Many times tested on other types of fighters.
The heart of the machine
Every famous aircraft was born thanks to the presence of a successful engine. The aerial triumph of the La-5FN, MiG-15 or British Spitfire begins with the stories of the ASh-82, Klimov VK-1 and Rolls-Royce Merlin engines. Because the best ideas of aircraft designers are meaningless without the power plant of the required parameters. A weight coil is “tied” to the engine. Performance characteristics at a designated take-off weight and combat load.
Technological level 1960-1970s allowed the creation of combat-ready single engine fighters with a normal take-off weight of 12-15 tons. The maximum take-off weight of such aircraft could reach 17-19 tons. Examples are the MiG-23, F-16 or Mirage 2000.
At the beginning of the XXI century, a single-engine F-35 was created with a normal take-off weight of over 20 tons.
The prerequisite for the creation of such an aircraft was the Pratt & Whitney F-135 engine, which develops more thrust than both engines of the MiG-35 fighter. This comparison was made not with the aim of discrediting domestic technology, but with the aim of demonstrating the seriousness of the intentions of the "potential enemy".
The hefty "Penguin" did not appear from scratch. At hand, the designers, first of all, had an engine that made it possible to lift a 20+ ton fighter into the air. With the ability to provide the F-35 with peer-to-peer thrust-to-weight ratio.
The fact that the thrust-to-weight ratio with a normal take-off weight lies in the accepted range for fighters of 4/5 generations is evidenced by shots with flights at supercritical angles of attack, "back" forward. This is possible, first of all, due to the impressive traction of Pratt & Whitney.
Before the appearance of the domestic engine of the "second stage" within the framework of the Su-57 project, there were no close analogues of the F-135 in the world. Declared 13 tons of thrust in non-afterburner mode and 19 tons in afterburner with its own "dry" weight of 1700 kg. A significant gap from the characteristics of its predecessors. This is the engine for a new generation fighter jet.
As a general summary. One engine is beneficial in terms of cost and performance.
Regarding the situation with engine failure, the incidents disprove the belief that twin-engine fighters are more reliable. Loss of thrust became a critical situation, depriving the pilots of the opportunity to continue flying. The pilots did not rely on a second, serviceable engine, but on the ejection seat and the strength of the parachute lines.
Radar
The mass of the airborne radar is only 1% of the take-off mass, but it is the characteristics of the radar that determine the capabilities of modern fighters. Fact: over the past few decades, in air battles, where 4th generation fighters were used, 100% of victories were won with the use of medium and long-range missiles (URVV).
The following is known about the F-35 radar. This is one of three types of radars for fighters (along with the Raptor radar and the Russian 0N36 Belka), originally created with the expectation of using AFAR.
The RBE-2AA radars of the French Rafale fighters and other modern radar modifications of the 4+ generation fighters use outdated architecture and software inherited from their base versions with PFAR. According to the Western military themselves, such developments are a compromise solution that is not able to realize the full potential of an active phased antenna.
It would be too naive to hope that accurate information about the characteristics and capabilities of the AN / APG-81 will be made public. In the brochures themselves, there are very remarkable images of the terrain taken with the F-35 fighter's radar. The declared resolution of 30 x 30 cm allows you to reconstruct the appearance of the target. Distinguish a truck from tank.
The AN / APG-81's capabilities against air targets are apparently not so remarkable, so less attention is paid to them.
AFAR has lower emitted power and detection range. From the positive aspects - extended viewing angles, simultaneous tracking of air and ground targets, great stealth when working. The use of the radar for communication with other aircraft of the group is declared. In this mode, the radar becomes a Wi-Fi access point with a data transfer rate 500 times faster than the standard NATO Link-16.
Neutral summary: the F-35 fighter is equipped with one of the most modern radars, which has certain advantages over the previously created radars.
weaponry
A combat aircraft is a structural element of the armed forces and the military-industrial complex as a whole. History knows examples when a wide range of weapons and an aircraft design compatible with the available ammunition became the most valuable feature in combat conditions. This was, for example, Junkers-88. Absolutely mediocre in everything, except for the presence of a 4-meter "hole" in the middle, most loaded part of the fuselage. A huge bomb bay and a seemingly ordinary compartment, the volume of which was rationally distributed when loaded with standard Luftwaffe bombs.
The F-35 project provides for the use of almost all NATO aircraft ammunition to destroy air, land and sea targets.
Among them, one can distinguish, for example, such patterns as scheduling SDBs (Small-Diameter Bomb). Compact ammunition with foldable wings, best suited to suspension requirements in internal weapon bays.
nearly invisible
The objectives of this direction are to reduce the detection range and reduce the likelihood of "capture" by the heads of the controlled weapons... The idea has received comprehensive development over the past decades. The "probable enemy" has always declared the priority of "stealth technologies". The use of "stealth" in combat has shown controversial results.
The F-35 fighter has a wide range of stealth elements. These are parallel edges of the wing and horizontal tail, S-shaped channels of air intakes, an engine completely recessed into the fuselage, sawtooth edges of the covers of technological openings, an invisible canopy and a "magic" radio-absorbing coating, about which practically nothing is known. Unlike Raptor and V-2 Spirit, on the multipurpose F-35 it was decided to abandon the flat engine nozzle, which means greater thermal signature.
Designated technical solutions, incl. associated with the parallelism of the edges of the aerodynamic planes, are not a sign of poor flight performance. Similar solutions are observed in the design of the domestic Su-57, which is presented as a fighter with the highest flight characteristics among its peers.
Finale
As of early August, 670 F-35 units of all modifications were built. The fighter entered service with the air forces of eight countries of the world. The implementation of contracts in the interests of six more countries is in the process.
The F-35 fighter is presented in three versions, the appearance of which seems logical when creating a "mass" combat aircraft of this class. An example is reports of a promising Su-75 Checkmate. In which the possibility of creating a deck version and VTOL aircraft was also evaluated.
With a total flight time of 400 aircraft accidents, 000 F-4 units were lost, which brings the operation of this type of aircraft closer to civil aviation safety standards.
In open sources, numerous photo and video materials are presented on the implementation of such elements as refueling in the air at night or performing takeoff and landing operations from the decks of aircraft-carrying ships, incl. at night. Evidence that the fighter is actively mastered by personnel and is regularly operated in conditions that are far from the ideal conditions of test centers.
On the other hand, official sources do not hide a significant number of identified shortcomings and design errors. The Americans already had a similar experience with the creation of a massive multi-role fighter. Which ended with unparalleled in terms of time and cost "work on mistakes."
MSIP (Multinational Staged Improvement Program) program for bringing to life the almost incapacitated F-16. Which at first could not fly in the dark and use weapons outside the line of sight. Despite such problems, the fighter had potential and it was "refined" to the required level. The F-16 never learned to fly at high angles of attack. But he became an indispensable participant in all armed conflicts. The adventures of this "miracle Yuda" deserve a separate story.
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