Conventional Takeoff And Landing Research Articles

Low-Voltage, High-Frequency Synchronous Motor for Aerospace Applications

This article details the design of a permanent magnet synchronous electric motor prototype dedicated to the direct drive of the propeller for VTOL (Vertical Take-Off and Landing) and CTOL (Conventional Take-off and Landing) aircrafts. Our main aim is to maximise the power-to-weight ratio whilst not compromising the efficiency and the reliability. The originality of the research is based on the implementation of an armature winding using solid copper bars; we show that it is possible to use such an approach in an electric machine operating at very high frequency (1800 Hz) through a precise study on the shape of the bars to counter the additional losses. A prototype has been successfully manufactured; manufacturing details and some of the experimental test results are presented here.

Development, Modeling and Control of a Dual Tilt-Wing UAV in Vertical Flight

Hybrid Unmanned Aerial Vehicles (H-UAVs) are currently a very interesting field of research in the modern scientific community due to their ability to perform Vertical Take-Off and Landing (VTOL) and Conventional Take-Off and Landing (CTOL). This paper focuses on the Dual Tilt-wing UAV, a vehicle capable of performing both flight modes (VTOL and CTOL). The UAV complete dynamic model is obtained using the Newton–Euler formulation, which includes aerodynamic effects, as the drag and lift forces of the wings, which are a function of airstream generated by the rotors, the cruise speed, tilt-wing angle and angle of attack. The airstream velocity generated by the rotors is studied in a test bench. The projected area on the UAV wing that is affected by the airstream generated by the rotors is specified and 3D aerodynamic analysis is performed for this region. In addition, aerodynamic coefficients of the UAV in VTOL mode are calculated by using Computational Fluid Dynamics method (CFD) and are embedded into the nonlinear dynamic model. To validate the complete dynamic model, PD controllers are adopted for altitude and attitude control of the vehicle in VTOL mode, the controllers are simulated and implemented in the vehicle for indoor and outdoor flight experiments.

Multimission STOVL application of a hybrid powered-lift system

Short Takeoff and Vertical Landing (STOVL) aircraft are options for future replacement of sea-based Conventional Takeoff and Landing (CTOL) aircraft. A conceptual design study was conducted to evaluate the feasibility of a minimum-cost modification of the Lockheed S-3A airframe to an S-3 STOVL configuration. The STOVL concept is based on the use of four TF34 turbofan engines and the application of Lockheed's Advanced Internally Blown Jet Flap/Vectored Thrust (AIBF/VT) hybrid powered-lift system. The S-3 STOVL deck performance estimates are presented along with mission performance comparisons with four CTOL aircraft. These CTOL aircraft are the C-2A, E-2C, S-3A, and KA-6D for the Carrier On-board Delivery, Airborne Early Warning, Antisubmarine Warfare, and tanker missions respectively.

CTOL, STOAL, V/STOL - An operational comparison for forward deployedCVNs

A computerized model has been developed to aid in studies of mission system effectiveness for aircraft carrier operations with conventional takeoff and landing (CTOL), short takeoff arrested landing (STOAL), and vertical or short takeoff and landing (V/STOL) aircraft. The model systematically evaluates sensitivities to key input parameters associated with flight deck imposed limitations on aircraft movement, handling, and scheduling of major deck cycle operations. Sorties, time on station, and airwing requirements are predicted as a function of aircraft availability over a range of target and stationkeeping radii. Results are presented for the sea control and power projection missions which indicate significant operational advantages for V/STOL aircraft operating from large deck CVN class carriers or proposed smaller aircraft carriers.

SEAKEEPING PERFORMANCE COMPARISON OF AIR CAPABLE SHIPS

ABSTRACTThe on‐going debate regarding the merits of large versus small aircraft carriers raises several issues concerning the ability of various ship configurations to support sea based air operations. One such issue is the question of the relative seakeeping performance of ship alternatives. In an effort to shed some light on the matter, a comparative seakeeping assessment of nine air capable ships covering a wide range of size and hull form was performed. An evaluation of the impact of aircraft and ship motion limitations on sea based air operations and a comparison of the relative ability of the ships to conduct air operations while in a seaway are presented. The specific air operations considered are launch, recovery, and support of aircraft. The ships evaluated are CVN‐71, CVA‐67 (MR), CVV, LHA‐1, VSS‐D, DDV‐2, DDV‐1D, DD‐963, and SWATH‐6. These ships have the combined capability to operate Vertical Takeoff and Landing (VTOL), Conventional Takeoff and Landing (CTOL), Short Takeoff and Arrested Landing (STOAL), and Short Takeoff and Vertical Landing (STOVL) type aircraft. Results indicate that seakeeping performance generally degrades with decreasing displacement, that SWATH‐6 performance is the least degraded, that elevator wetness can be an important degrader for ships with lower freeboards, that roll motion can be an important degrader for ships under 60,000 tons, and that percent time of operation is strongly dependent on the prevailing wave and wind environment.

Operational Constraints for STOL Aircraft

The Short Takeoff and Landing (STOL) transportation system has been proposed as a solution to short-haul transportation congestion, because it 1) operates independently of the existing Conventional Takeoff and Landing (CTOL) system; 2) offers more convenience to short haul travelers; and 3) relieves congestion at major airports. However, the STOL transportation system encounters operational constraints which differ from current CTOL aircraft. These constraints are: economics, short-haul market characteristics, operating environment, and community acceptance. This paper discusses how these constraints influence the STOL aircraft's size, speed, propulsion system, takeoff/landing performance, and maneuverability.