Three variants of convertiplanes on the HSVTOL platform
American company Bell Textron Inc. has extensive experience in the field of vertical take-off and landing aircraft. Right now, it is being used in the development of a new concept project for a tiltrotor family with a number of characteristic features. The other day, the developer company first showed the appearance of such a family and revealed its features.
Currently, as part of the Pentagon's programs, Bell Textron is creating two promising tiltrotors with different capabilities - the V-280 Valor and the V-247 Vigilant. In addition, research is being carried out, necessary for the further development of the direction and the development of the following projects.
In 2017-2020 Bell-Textron has patented several tiltrotor schemes with various features. Various versions of the aerodynamic appearance, several schemes of the power plant and the carrying system are proposed. In particular, a tiltrotor with propeller blades folding in flight, a hybrid gas turbine-electric power plant, etc. have been developed.
In April 2021, the Air Force Research Lab (AFRL) issued an order to the company to develop concepts for a military tiltrotor. The cost of such work was estimated at 950 thousand dollars. It was reported that the goal of the project is to create a promising high-speed vertical take-off and landing aircraft (High-Speed Vertical Take-Off and Landing, HSVTOL).
The new research project is being carried out for the benefit of several entities. Its practical results may be of interest to the Air Force, ILC, Navy and Special Operations Forces. They require high-speed vertical take-off aircraft to effectively solve some problems, and for this reason several new programs have been launched, such as FVL and HSVTOL.
On August 2, the contractor company for the first time disclosed information on the new project. The press release contained the main tasks of the current work and plans for the further development of the project. In addition, they published a computer image of three products of the promising HSVTOL family at once.
Carrying system of the tiltrotor, described in the patent US20190248483A1 from 2018.
Goals and objectives
The main goal of the HSVTOL project from Bell Textron is to find and test solutions for the subsequent creation of real aircraft of different classes and for different purposes. By scaling the main ideas and technologies, it is necessary to ensure the development and construction of aircraft with a take-off weight of 4 thousand pounds (1,8 tons) to 100 thousand pounds (45,4 tons).
The HSVTOL device must be capable of vertical take-off and landing, hovering, etc. and show high takeoff and landing characteristics. The longest possible continuous hovering should be ensured. The downdraft flow in this mode should be minimal to exclude negative phenomena. The tiltrotor must be capable of level flight at a speed of at least 400 knots (740 km / h).
It is planned to create manned and unmanned aerial vehicles based on key technologies and solutions. Such equipment will be able to solve a wide range of transport, combat and auxiliary tasks. However, the army has not yet announced its plans for the creation and implementation of aircraft with such capabilities.
Bell-Textron revealed the possible appearance of three aircraft of the HSVTOL line at once. They have some common features that indicate the application of common solutions. At the same time, there are significant differences associated with different purposes and goals of specific projects.
The shown tiltroplanes are "built" according to the normal scheme with a spindle-shaped fuselage, straight wing and two-fin tail. At the ends of the wing are engine nacelles used for vertical takeoff / landing and flight at low speeds and transient conditions. The devices are shown in high-speed flight mode: the propellers are stopped, and their blades are folded along the nacelles.
The type of power plant has not been specified, but new technologies have been reported. It can be seen that the aircraft have air intakes of different locations, which indicates the use of turboshaft or turbojet engines. At the same time, engine nacelles do not have nozzles.
Bell V-280 Valor - already flying tiltrotor for FVL
The HSVTOL concept probably uses ideas previously described in one of Bell-Textron's patents. Then it was proposed to equip a tiltrotor with a turbojet engine connected to a generator, and place electric motors in the nacelles on the wing.
A common part of different projects will be modern digital control systems that can take on some tasks and relieve the pilots. In addition, due to this, the groundwork for the creation of unmanned vehicles will appear.
Such an aircraft will perform takeoff, transition to level flight and initial acceleration using rotors with electric motors - like "traditional" convertiplanes. After gaining the required speed with obtaining the required lift from the wing, HSVTOL will be able to turn off the main engines and fold the blades, and the thrust will be created by the turbojet engine.
In fact, the HSVTOL project is combining several promising technologies, which is expected to provide an advantageous performance ratio. Thus, rotary engine nacelles with rotary propellers will give vertical take-off and landing, a jet engine will accelerate the car to high speed, a hybrid power plant will increase energy efficiency, and control automation will simplify the work of pilots and allow the creation of unmanned modifications.
However, almost all of these technologies are not mature and need further development. It is necessary to create bench and prototypes for testing and debugging of various kinds, providing for independent and joint testing of units.
The published image shows the fundamental possibility of creating a heavy transport tiltrotor. Such an aircraft retains its normal aerodynamic design, but the air intake had to be moved to the upper surface of the fuselage. A large cargo compartment with aft loading is also provided. The estimated tactical and technical characteristics of the vehicle are unknown.
Bell V-247 unmanned aerial vehicle in development
The second aircraft shown is smaller and has an unclear purpose. It has a cargo-passenger cabin with side entry and side air intakes. The third variant of HSVTOL is even smaller and outwardly similar to the previous one. However, he does not have a flashlight, which speaks of the unmanned nature of the development. What payload such a UAV can carry is unknown.
It is possible that the HSVTOL program will not be limited to the three shown converters. At least at a theoretical level, other options for technology can be worked out on the basis of unified solutions. The actual size of the family and the number of projects will depend on the results of the current work and on the wishes of the customer.
In recent years, the US Armed Forces have paid great attention to the problem of aircraft that combine high takeoff and landing and speed characteristics. Various structures of the army need aircraft that do not need large take-off and landing sites, but are capable of transporting one or another cargo at high speed over a long distance.
Several projects of this kind are already being developed as part of the large FVL program, with an eye to production and real application. A number of prototypes have already been brought to testing and are successfully demonstrating high performance characteristics. In a few years, such equipment will have to get into the troops, where it will begin to replace the existing helicopters.
All these projects are based on modern technologies and components, which determines their capabilities and prospects. The new HSVTOL project, in contrast to them, provides for the search and use of completely new solutions, which have not yet been used in aviation... Its actual result will be recommendations for the further development of the direction of high-speed convertiplanes.
Project Completion Date Bell Textron Inc. have not been specified yet. The search and study of fundamentally new technologies and technical solutions will take several years. Then a prototype may appear, which will have to show the potential of the new concept. And only after that we should expect orders for the development of real equipment for use in the armed forces and other structures. Time will tell whether Bell-Textron's ideas will succeed in reaching this stage.