Itz-31
| Itz-31 | |
|---|---|
| |
| Itzcoyotl-Aketzalli Itz 31 in 1970 | |
| Role | VTOL transport |
| Manufacturer | Cuauhquetztia |
| Designer | YAT 50 |
| First flight | 15 February 1969 |
| Introduction | 1973 |
| Status | In service |
| Primary user | Zacapine Armed Forces |
The Itz-31 is a vertical take-off and landing jet aircraft designed by the aerospace engineers of YAT 50 and manufactured by Cuauhquetztia for the Zacapine Armed Forces. Its primary role is as a military transport aircraft used by the Zacapine military and its allies, although a modified version serves as a carrier-capable airborne early warning and control aircraft with the Zacapine Navy. The highly unorthodox concept of a VTOL transport and utility jet offers unique advantages over helicopter and conventional fixed wing aircraft equivalents, being far more versatile than any conventional transport aircraft thanks to its capability to operate nearly anywhere, even from the cramped decks of aircraft carriers, while also offering significantly greater airlift capacity than all but the largest helicopter designs. However, the innovative design of the Itz-31 would also involve many unprecedented engineering challenges and would prove to be one of the most difficult and expensive aerospace design projects in Zacapine history. Despite its age, the Itz-31 remains a point of pride in the Zacapine military and engineering establishment thanks to its unique capabilities and the technical accomplishment it represents.
Development
The origins of the Itz-31 can be traced to the late 1960s initiative for the development of the VTOL aircraft for the Zacapine air forces and Naval Aviation units, part of the general military modernization initiative undertaken between 1966 and 1970 aimed at replacing and updating Xolotecate era military equipment. Once the general technology for the vertical takeoff and landing of jet aircraft had been established, it came under the close attention of military authorities in Zacapican who saw the potential for such craft to revolutionize their naval aviation forces and help to immunize their outlying air bases in the Zacapine north and on remote islands from being quickly shut down during an enemy surprise attack. The military wanted a series of modern aircraft that could be hidden under cover or within buildings and then take off with little more than a small launch area like an open field or even a road, and they passed on this project to the aerospace engineers of the YAT program. A trio of aircraft were originally requested, these being a fighter interceptor, a strike fighter and finally a military transport. While the Pilpiyotzin 191 strike fighter would be cancelled almost immediately, development progressed for a time on the experimental Pilpiyotzin 101, which would be canceled in 1970 by the Zacapine military after the prototype prepared by the YAT engineers failed to meet the expectations of the military examiners. This leaves the Itz-31 as the only survivor of the Zacapine VTOL aircraft initiative, although its development would nevertheless be difficult and experience many delays.
The lead designer for the Itz-31 project would be then-head of the YAT 50 bureau, Tochin Itzcoyotl, a veteran aerospace engineer and one of the pioneers of jet aircraft design in Zacapican. As one of the main proponents for the potential of VTOL technology in the Zacapine engineering establishment, he was the logical choice to spearhead the program. VTOL would prove to be a difficult technology to master, and served as the main stumbling bloc for the Itz-31's sister projects. During take-off or landing the aircraft would hover vertically, making all the conventional control surfaces of the aircraft useless in maneuvering and requiring complex jet thrust systems to all adjustments and maneuvers in hover mode. The large number of jets required to lift and maneuver a large aircraft and the fuel they would require increased the weight of the design significantly, requiring even more jets to compensate and further complicating the design process. In order to cope with the difficulties of the design Itzcoyotl elected to bring in Micol Aketzalli, a newcomer to the YAT program who had already become embroiled in the activities of the Zacapine aerospace engineering establishment and would soon become the strong advocate of many revolutionary ekranoplan projects of YAT 131. Aketzalli had rapidly become a specialist in the matter of VTOL propulsion and turbofan engines, leading Itzcoyotl to deem his expertise potentially critical to saving the Itz-31 project. Aketzalli was a novice in the field of turbojet design, but his addition to the project would allow lead designer Itzcoyotl to focus entirely on the challenges of the propulsion systems and accompanying computerized controls while Aketzalli handled the rest of the design process. Micol Aketzalli would later go on to apply much of what he would learn working with Itzcoyotl to his later projects, such as the complex VTOL turbofan system of the TC-14.
Ultimately, the saving grace of the Itz-31 project would be the interest of the Zacapine Navy in the project. The navy's interest in the VTOL capabilities of the all of the proposed aircraft was significant, as it would allow for smaller aircraft carriers which had previously only been able to launch helicopters to now field jet fighters and bombers. The Pilpiyotzin 191 and Pilpiyotzin 101 were beginning to run into problems in their troubled development, not least of which was the development of the revolutionary Tlo-26 by a rival team within YAT 50 which was threatening to render the development obsolete before it could even enter service. However, the Itz-31 had no such competition and would have the capability of serving in the niche of carrier-launched early warning aircraft capable of operating from the decks of small VTOL/STOVL only carriers. The need for such a craft had only emerged as a result of the navy's concurrent plans to launch its new line of large nuclear-powered aircraft carriers to project power on a global scale, carriers which would need carrier-launched aerial radar systems to be effective. While the navy had also considered a more conventional turboprop AEW aircraft, naval officials would be won over by Micol Aketzalli's ideas regarding the applicability of not only a potential AEW variant of the Itz-31, but its original transport model. Aketzalli successfully argued that the superior range, speed and lift capacity of the Itz-31 would allow a Zacapine naval squadron to launch and support and airborne assault on a target on shore while remaining well out of range of many land anti-ship missiles which could threaten landing ships. In particular, Aketzalli stressed the greatly increased range the Itz-31 could offer to Marine airborne units compared to any existing transport helicopter.
Design
The defining feature of the Itz-31's design, its VTOL capability, is provided by two large underwing thrust vectoring turbofan engines each providing 67 kilonewtons of thrust along with eight trubojets (4 in each wing-tip pod) providing an additional 20 kilonewtons of thrust apiece. The wing-tip pods are used for maneuvering and generating jet-powered lift for take-off and landing. The main underwing engines are capable of vectoring thrust to assist in take-off and landing, while their main role is forward thrust. As with other VTOL designs, the Itz-31 has conventional wings and its capable of unpowered gliding at high speeds and can also land conventionally in case of engine failure. The Itz-31 propulsion system is highly complex both mechanically and from the pilot's perspective, requiring significant maintenance to keep operational and a computerized fly-by-wire control system for the pilot to effectively control the aircraft during the delicate process of vertical take-off and landing.
Operators
Specifications
General characteristics
- Crew: Two
- Capacity: 36 troops or 24 casualty stretchers and 3,500 kg (7,715 lb) useful load
- Length: 20.53 m (67 ft 4 in)
- Wingspan: 18 m (59 ft 1 in)
- Height: 8.53 m (28 ft 0 in)
- Wing area: 57 m2 (610 sq ft)
- Gross weight: 22,453 kg (49,500 lb) (VTOL)
- Max takeoff weight: 27,422 kg (60,455 lb)
- Powerplant: 2 × Xe-53 turbofan, 68.95 kN (15,500 lbf) thrust each
- Powerplant: 8 × Xe-162 Vertically mounted turbojet lift engines, 19.57 kN (4,400 lbf) thrust each
Performance
- Maximum speed: 730 km/h (454 mph; 394 kn)
- Cruise speed: 650 km/h (404 mph; 351 kn)
- Range: 1,800 km (1,118 mi; 972 nmi) with maximum payload
- Service ceiling: 10,700 m (35,100 ft)
- Rate of climb: 19.2 m/s (3,780 ft/min)