Shahid Bahman Bagheri - IRGCN drone carrier - Design
Iran's new UAV carrier would de facto be the country's first near-dedicated ship rebuilt to launch UAVs. "Shahid Bagheri", unlike its classmates, will be able to carry many more drones. It is also possible that some kind of flight deck will be created on board the new Iranian ship for the use of heavy aircraft-type drones. The fact that the superstructure area is on the main deck of the ship means that the traditional aircraft carrier design is not possible. The added corners on the ship's deck are also not traditional. This probably refers to a runway that runs from rear to right forward of the fuselage.
Speaking in general about the experience of converting civilian ships into military ones, there was an excellent example of the Falklands War of 1982. There, British rebuilt container ships with Harriers showed themselves to be extremely worthy. In March 2013, DARPA began efforts to develop a fleet of small ships capable of launching and recovering combat drones without the need for large, expensive aircraft carriers. In England, the YXV Combatant, which is a special ship for combat drones, has been proposed to the Royal Navy. South Korea and China have also begun the study and development of UAV carriers and aircraft. In February 2021, Ismail Demir, head of the Turkish Defense Industry Agency, announced Baykar's development of a new type of UAV to be deployed on Turkey's first amphibious assault ship , the TCG Anadolu. According to the initial plans, the carrier was supposed to be equipped with F-35B fighters , but after Turkey was removed from the F-35 purchase program, the carrier was modified in the process to be able to accommodate UAVs.
According to satellite images obtained by the "Military Times" website 06 January 2023, the ship's deck had been removed to install a flight surface for launching drones. Engineers are adding a large flight deck to the starboard side of the ship, but at this time it is not clear whether a bulge will also be added to the starboard side of the ship. Since the ship's tower is located in the middle of the main deck, engineers will not be able to convert Shahid Mahdavi into a normal aircraft carrier. The recently added flight deck angles are also unusual. Therefore, it is likely that the flight deck of this ship will extend from left to right and pass in front of the ship's tower. Experts have told Military Times that the available images are consistent with the claims of the Islamic Republic to change the use of commercial ships. Iranian media had previously talked about changing the use of commercial ships to UAV carriers and using them to "increase long-range attack capabilities".
On 24 February 2023 Rear Admiral Alireza Tangsiri, the commander of the naval forces of Iran’s Islamic Revolutionary Guard Corps (IRGC) said, "This vessel is a UAV carrier with a runway of 180 meters, on which the aircraft has landed [vertically] on wheels and will also fly on wheels." He added, "About 30 Ashura-class combat boats are carried in the lower part of the Shahid Bagheri carrier." The Commander of the IRGC Navy also said: "The Shahid Bagheri float, which will be completed in the future, besides having a flotilla inside it, also has a runway on which the UAV can move and fly and can sit on it when returning. Shahid Bagheri's hull is 240 meters long and 21 meters high, equipped with helicopters, missiles and drones. This vessel is being built in such a way that about 60 drones can fly and sit on its deck."
The most notable design feature of the Shahid Bagheri is the innovative approach to an angled flight deck design, where landing aircraft were effectively separated from launching aircraft. Now a common feature of aircraft carriers, British naval aviators showed their counterparts in the U.S. Navy the concept of the angled flight deck. To allow a plane that had missed the arresting gear to get back in the air safely, the flexible deck would have to be located away from the deck park. His solution was to have “separate landing and take-off decks.” The Americans saw its value almost immediately and embraced it. That seemed to make the process of adopting an innovation within the U.S. Navy straightforward. The angled flight deck improved the pilots' safety, and the crew of the ship working on the flight deck.
The Shahid Bagheri angled flight deck solves a rather different problem. The Anglo/American innovations of the angled flight deck; the steam catapult; and the mirror and lighted landing aid, enabled pilots to land heavy and fast jet aircraft on a carrier's short and narrow flight deck. On the Shahid Bagheri, the angled flight deck allows relatively light and slow unmanned air vehicles to land, without necessitating the demolition of the ship's legacy aft superstructure. This is the location of the ship's bridge, crew cabins, and other relatively complex elements that would be tedious to replace with an entirely new construction at the side of the ship.
Under ordinary circumstances, very little difficulty is experienced by aircraft pilots in landing their craft on the usual commercial or military airfield, since the length of the runways is adequate to meet the requirements of any particular aircraft to which landing clearance has been granted. However, the same is not necessarily true of mobile landing platforms or decks such as are found on Naval aircraft carriers, such decks rarely exceeding 900 feet in length. In spite of the presence of resilient arresting cables which are designed to intercept and rapidly decelerate an aircraft following touchdown, it is extremely important that the entire landing operation proceed according to a prescribed pattern as otherwise damage to the aircraft and/ or injury to the pilot is likely to occur.
To land on an aircraft carrier, current Navy aircraft require an arresting gear. The term "extremely" short takeoffs and landings refers to takeoff and landing distances [un-arrested] in a range of from about 90 to 250 meters (300-800 feet). This is accomplished by reducing the takeoff and landing speeds to between about 111 to 185 km/h (60 to 100 knots). The landing distance (Sg) of any aircraft is directly proportional to the square of the touchdown speed. This distance is independent of the aircraft size and weight.
On the other hand, a few years ago a set of satellite images showed an F-4 was practicing landing on the ship with the help of the hook system on the ship. Some thought this may have been the tests for this catapult and hook system of this ship, but it turned out not to be. It was initially unclear whether a pedestal would be added to the starboard side of the ship. The fact that the superstructure area is on the main deck of the ship means that the traditional aircraft carrier design is not possible. The added corners on the ship's deck are also not traditional. This probably refers to a runway that runs from rear to right forward of the fuselage.
At present, the landing process of most carrier-based unmanned aerial vehicles needs close-range manual remote control, and the unmanned aerial vehicles are not suitable for the ocean working scene of carrying the unmanned aerial vehicles by unmanned ships, and particularly, no precedent exists how to automatically land the unmanned aerial vehicles on carrier-based platforms. The conventional unmanned aerial vehicle guided landing method (GPS guide) has a good effect in a land target area, but is difficult to adapt to a swaying unmanned ship based system, and the unmanned aerial vehicle cannot land accurately and cannot guide accurately at different heights and speeds due to the fact that transverse and longitudinal swaying exists in the target area in the last stage and information errors exist.
By using visual identification, the combined navigation is carried out by combining GPS position information sent by a ship, so that the problems that the visual system loses a target and cannot track quickly due to the fact that the ship is too fast are solved effectively; and predicting the position-time relation and the attitude-time relation of the landing platform through a digital information filtering fusion algorithm to obtain a prediction function of the mobile carrier about attitude and position-time.
There is no example of a drone carrier in the world, so it may not satisfy all of Iran's needs in the first step, but it is unique in its kind. Changing the location of the island of this ship should be a priority, because it is easier to hit the imaginary island when it takes off, and it is also easier to monitor the drones. The sea is always facing and this momentary displacement causes the landing to become a challenge, especially the landing on aircraft carriers, so the first and most important part of this ship is the proper stabilizer that can change the ship's center of gravity at any moment for the stability of the ship. Artificial intelligence should be considered suitable for landing and taking off in the ship, which will be more difficult anyway due to the lack of a foreign model.
One way to reduce the takeoff speed is to increase the angle of attack that the aircraft can generate during the takeoff run. The ski-jump takeoff technique developed by the United Kingdom Royal Navy provides a means for an aircraft to rotate to a higher angle of attack. Conventional aircraft using this technique are still limited to speeds above stall because the aerodynamic control surfaces are needed to maintain aircraft stability. The takeoff distance goes up by the square of the velocity, so the aircraft needs to takeoff at the lowest possible speed. The ski jump ramp works by rotating the velocity vector of the aircraft up and using the aircraft's momentum (rather than aerodynamic force) to lift it off the ground. This principle is exactly the same a human skier going over a bump in the snow and flying into the air, even though he has no wings.
With a ski-jump ramp added at the end of the runway like Russian or English ships, it can carry and fly larger drones. Ramped runways of the type referred to as "Ski-Jump" runways were first developed for use by V/STOL aircraft such as for example the Hawker Siddeley Harrier. Although the Ski-Jump principle is associated with the V/STOL Hawker Siddeley Harrier which employs a tandum bicycle type main undercarriage with stabilising outrigger wheels at its wing tips, it is equally applicable to all forms of winged aircraft. Experience has shown that although the main undercarriage wheels of the Harrier aircraft leave the uppermost edge of the Ski-Jump at different points in time the longitudinal stability of the aircraft at launch is not unduly affected. Aircraft employing a tricycle type undercarriage however can present more serious difficulties when being launched from a conventional Ski-Jump ramped runway. Most conventional aircraft with a tricycle undercarriage carry between approximately 1/8 and 1/4 of their weight on the nose wheel and if launched from a Ski-Jump the nosedown couple exerted on the aircraft when the nose wheel clears the edge of the runway and the main wheels are still on the runway could well be insufficient to adequately counter the nose-up rotation imparted by the runway geometry. The inertia of the aircraft puls the relatively ineffective aerodynamic controls at the low launch speeds could make this residual nose-up motion a serious problem.
There is at least one elevator to carry the drones to the lower part of the ship, which is the best way to service and store the drone, in the lower part of the ship. Modern aviation mother ships supporting aircraft and helicopters are provided with hangar, so that warship crew can have good temperature, humidity environment and cleaner enclosure space to carry out various maintenance support operation to carrier-borne aircraft. The turnover scheduling of carrier-borne aircraft on warship that hangar reclaims for standby for takeoff and landing has a vital function. The hangar of the aircraft carrier that various countries build all is located in the warship body below flight deck, the advantage of this placement scheme is length and width that flight deck and hangar deck overlap make use of aircraft carrier space.
Its major defect is because the carrier-borne aircraft on flight deck and on hangar deck are distributed with difference nearly ten meters, the aircraft have to be carried in the vertical direction by the power-actuated aircraft elevator. The existence of aircraft elevator adds main equipment in the warship and the installing space taken thereof. The elevator itself and passage, bearing and the hangar door opening that arrange around it all constitute the weak part in flight deck and warship structure. The process of carrier-borne aircraft elevator increases the difficulty of operation, extends the movement of carrier-borne aircraft on warship and the time needed for route of scheduling. In addition, the carrier-borne aircraft hangar arranged under flight deck needs to have comparatively large span and clear headroom, which makes the structure of warship body and loaded state be tending towards complicated, which also creates many restrictions to the layout in other cabins in the warship hull.
The Shahid Bagheri will become a good flagship of the Iranian “special naval unit.” Yes, its drones, especially the Shahed 136, will be useless against a modern US naval formation, because American ships will simply shoot down all the drones on approach. However, ship-borne drones are ideal against ground targets or the fleet of regional powers . They are cheap and easy to operate, and due to the ship base they can be delivered many thousands of kilometers from the Iranian border. The best drones that can be used are Kopi RQ 170 drones, especially with jet engines. These UAVs are not completely radar-evading, but they have a low radar RCS, we should produce some radar-evading samples using radar-absorbing colors. These UAVs must also have SAR radar.
This ship can fire ballistic and cruise missiles as well. At least this equipment will be placed inside the ship and there will not see ten containers on top of the ship. This ship needs a long-range radar so that it can see all the events in its range from a longer range. It is made with a different technology and... but anyway, according to the type of coverage, there is definitely a need for a long-range radar. The installation of a cloud computer, which can be built by paralleling several CPUs in series, is also recommended in this ship, because at some point, operators will need a lot of information, including the state of the wind, the temperature, the wave level, the speed of the ship and the speed forr the drone landing and taking off, and the artificial intelligence of the drone to help it land and take off, a bit of delay is equal to disaster. By sharing information, this ship can reach a greater range with the communication relay of drones.
Taking America as the largest owner of aircraft carriers as a model, the duty of defending the ship is the responsibility of the surrounding vessels and destroyers, then Iran can put the defense of the ship in charge of vessels such as Shahid Soleimani and the Zulfiqar boat, or missiles installed as long-range defense on aircraft carriers and leave short-range defense to boats like Zulfikar through network-based warfare.
Container ships are large vessels that carry dry cargo in intermodal containers. Unlike general cargo ships, container ships use containers that are standardized in terms of size and container ship capacity. Standard-size containers maximize cargo space, allowing each ship to carry a maximum amount of goods. The latest container ships easily transport 15,000 to 21,000 TEUs, and sometimes more.
A bulkhead is a vertical partition walls which subdivide the ship interior into watertight compartments. Bulkheads reduce the extent of seawater flooding in case of damage and provide additional stiffness to the hull girder. One of the first ships capable of crossing the Atlantic, the Great Eastern, had many safety features designed into her structure. Built in 1859, she was by far the largest ship ever built at that time. On one of her voyages she hit a rock that made a hole in the hull thought to be 60 times the area of the one in the Titanic. Yet her internal bulkheads were so extensive and strong that she hardly even listed.
On 14 April 1912, the RMS Titanic collided with a massive iceberg, which caused water to flood into six major watertight compartments. Bulkheads running the height of the ship prevented the creation of large rooms, such as dance halls, and they also restricted the movements of waiters and passengers. So, gradually, year-by-year safety measures were reduced. Titanic was provided with 15 watertight bulkheads and could safely remain afloat with any two compartments flooded. As the water filled up one of the compartments, over-topped the bulkhead and entered into the next compartment from the top. Had the bulkheads been taller in the Titanic, the sea water would not have flowed from one compartment to another and the ship would not have sunk. As a result of the Titanic disaster, changes were made in ship design, such as double hulls and taller bulkheads.
Bulkheads are an essential structural component of any ship, helping separate the vessel into watertight and fire-resistant compartments. dividing a ship into smaller parts contributes to strengthening its hull. Bulkheads also support the deck, making it sturdier and more resistant to damage. Bulkheads add the possibility to seal damaged compartments and isolate them from the rest of the ship. This way, the captain can keep the ship afloat with the rest of the compartments remaining entirely usable. Transverse bulkheads divide the ship from side to side and are habitually used to create watertight compartments on the vessel. Longitudinal bulkheads extend fore and aft and divide the vessel along its length. Watertight bulkheads are usually equipped with watertight doors, that allow crew members to freely navigate the inside of the vessel. The bulkhead positions are arranged with distance of multiple integer of container length The number and location of the transverse bulk-heads, although strongly limited by the need to be compatible with dimensions multiple of the container size, modify the internal arrangement of the containers and has an influence in the total number of TEUs carried.
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