Browse Topic: Cowlings

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PIV Investigation of Helicopter Rotor Hub and Cowling Wake MitigationF-0082-2026-00985/5/2026
Helicopter tail shake constitutes a significant limitation to both passenger comfort and aircraft stability. Under powered descent conditions, elevated Angle of Attack (AoA) cause flow separation around the rotor hub and engine cowling, leading to the development of an unsteady wake dominated by large-scale turbulent structures. To support the helicopter tail shake phenomenon investigation, a dedicated Particle Image Velocimetry (PIV) experimental setup was designed in this work, together with four aerodynamic devices aimed at mitigating tail shake. These components were then tested through a wind tunnel campaign with the PIV setup. The proposed aerodynamic components were conceived to either deflect the hub wake away from the tail empennages or to decrease the Turbulent Kinetic Energy (TKE) within the wake. To achieve these objectives, a dorsal fin, a horse-collar, and two spoiler configurations inspired by automotive applications were designed and experimentally evaluated. The devices were tested both as standalone solutions and in combined arrangements on a scaled helicopter wind tunnel model featuring a rotating hub and blade shanks. The vertical velocity component, was used as an indicator of wake deflection, and the Turbulent Kinetic Energy was used as an indicator of wake turbulence. The Horse Collar and the Large Spoiler showed a reduction in both indicators suggesting possible tail shake mitigating capabilities, and additional improvements were achieved when the two devices were deployed in combination.
Campanardi, Gabriele Giuseppe, Zanotti, Alex, Zaccara, Mirko, Celada, Luca
RACER high-speed demonstrator: Rotor and rotor-head wake interactions with tail unitF-0074-2018-126995/7/2024
ABSTRACT Within the framework of NACOR project in CleanSky 2 AIRFRAME ITD, ONERA and DLR performed parallel investigations dealing with the RACER high-speed demonstrator, and especially with its tail parts, each partner respectively focusing on vertical fins (ONERA) and horizontal stabilizer (DLR). During this design phase, most of the CFD simulations were steady-state and neglected the effect of the rotor (or rotor-head) and of the propellers. It however turned out that the rotor-head had a significant effect on the vertical fins and that it was essential to take into account its rotation in time-accurate simulations: the wake from the rotor-head, the upper deck and the engine cowlings indeed strongly impacts the left vertical fin because of the clockwise rotation of the rotor-head. It induces strong oscillations on the tail unit loads, and the mean tail unit lateral thrust is also significantly increased. Moreover the main conclusions of this 'aerodynamic interactions' investigation are almost identical, no matter what the computed configuration: rotating rotor-head, rotating rotor-head with actuator-disk, rotating full-rotor or rotating full-rotor with propellers effect.
Lienard, Caroline, Fukari, Raphaël, Salah, Itham, Renaud, Thomas
Modeling Activities of Propulsion System Engine Installation SurveyF-0080-2024-13525/7/2024
The multi-role utility helicopter T625 GÖKBEY is designed by Turkish Aerospace and it is equipped with a pair of two-spool CTS800-4AT turboshaft engine developed by Light Helicopter Turbine Engine Company (LHTEC). Components of the cowlings, intakes and exhausts were designed with supplementing CFD analyses and performance of various alternatives were evaluated. Final designs were achieved based on the helicopter performance and engine limits. In order to verify the estimated engine installed performance in design phase, performance of the instrumented engine with its integrated equipment on the platform is examined using flight test data. This paper focuses on the CFD simulations based performance predictions of the air induction system, exhaust system, and IPS blower exhaust. A comprehensive study is assessed to create more realistic models by using flight test data.
Sancar, Emre, Ezertaş, Ahmet Alper, Bayat, Akay, Çakıroğlu, Taylan, Daldal, Abdurrahman Burak
Improve Heat Resistance of Composite Engine Cowlings Using Ceramic Coating Materials, Experimental Design and Testing01-11-01-00046/4/2018
A large amount of heat generated in the engineering compartment in a hovering helicopter may lead to premature degradation of inner skin of its engine cowling and cause serious failure on the engine cowling. This study proposes a solution of improving heat resistance of the helicopter engine cowlings by replacing the currently used intumescent coating with a ceramic coating material, Cerakote C-7700Q. Oven and flame tests were designed and conducted to evaluate the heat resistance of Cerakote C-7700Q. The test results show that the currently used painting scheme of the engine cowlings failed the 220°C oven test while after replacing the epoxy seal coat with the Cerakote, the new painting system passed the 220°C test in regards to painting bubbling. Based on that, a new painting scheme with C-7700Q implemented was recommended. It is suggested that the most time- and cost-effective solution to improve thermal performance of the helicopter engine cowlings is to repaint the current engine cowlings with the proposed new three coating system of Cerakote, surface protection HS7072-622, and intumescent paint as a fireproof lacquer. This study also explains why serious appearance defects occurred in the inner skin of the engine cowling when the aircraft is hovering. The present work can be converted to a design project for senior mechanical engineering students to develop their design and teamwork skills and enhance their capacity for solving real-world engineering problems.
Liu, Yucheng, Sippel, Thomas, He, Ge
Improve Heat Resistance of Composite Engine Cowlings Using Ceramic Coating Materials, Experimental Design and Testing2017-01-21309/19/2017
Oven and flame tests were designed and conducted to evaluate the heat resistance of a ceramic coating material, Cerakote C-7700Q, and evaluate its viability to replace the intumescent coating as one painting material for helicopter engine cowlings. The test results showed that the currently used painting scheme of the engine cowlings failed the 220°C oven test while after replacing the epoxy seal coat with the Cerakote, the new painting system passed the 220°C test in regards to painting bubbling. This study explained why serious appearance defects occurred in the inner skin of the engine cowling when the aircraft is hovering and suggested that one most time- and cost-effective solution is to repaint the current engine cowlings with a new three coating system of Cerakote, surface protection HS7072-622, and intumescent paint as a fireproof lacquer. The proposed study can be converted to a design project to senior mechanical engineering students to develop their design and teamwork skills and enhance their capacity for solving real-world engineering problems.
Liu, Yucheng, Sippel, Thomas, He, Ge
Cylinder Block Temperature Mapping and Development of Cooling Cowl for Reducing the Maximum Liner Temperature2012-01-04054/16/2012
To improve the performance and durability of two-stroke engines, temperature of the liner/block is an important parameter, which needs to be optimized. In this paper, an attempt is made to measure and investigate the maximum liner temperature of a forced-air-cooled two-stroke engine. The vehicle was tested on both chassis dynamometer and test track to identify the maximum liner temperature during operating conditions. Thermocouple locations were selected at or near the hot spots (TDC & Exhaust port) in the cylinder block. The chassis dynamometer test revealed that the maximum liner temperatures for the test vehicle were near the exhaust port reference position (34 mm from the top face of cylinder block) and TDC reference position (8 mm from the top face of cylinder block near the exhaust port). The Computational Fluid Dynamics (CFD) simulation was used to study the flow pattern around the block and the results revealed that design modifications can be done on the base cowl to improve and optimize the cylinder block liner temperature. Hence, the base cowl was experimentally modified using prototype cowls and was tested on chassis dynamometer to verify the temperature reduction. The target of reducing the maximum liner temperature for the test engine below the critical value (240°C) was achieved using the finalized experimental prototype cowl. Confirmation trials on the test track for the finalized prototype cowl demonstrated that there was a temperature reduction of 9% at exhaust reference position and 5% at TDC reference position.
T, Vipin Sukumaran, Kolluri, Sandeep, Joseph, Sumith, Sreenivasulu, T., Parthiban, R, Umate, Mohan D
Aircraft Tow BarARP1915D (Historical)9/13/2010
This SAE Aerospace Recommended Practice (ARP) outlines the basic general design considerations for transport aircraft tow bars. It does not cover the requirements for tow bars intended for aircraft with a maximum ramp mass (MRW) below 8600 kg (19 000 lb).
AGE-3 Aircraft Ground Support Equipment Committee
Aircraft Damage Caused by Ground Support EquipmentAIR1589A (Historical)12/9/2009
Only those incidents where a piece of ground support equipment directly associated with the "turnaround" servicing of an aircraft was involved are reviewed. Specifically excluded are those incidents that occurred during heavy maintenance, overhaul activity, or aircraft taxiing.
AGE-3 Aircraft Ground Support Equipment Committee
Aircraft Tow BarARP1915C (Historical)4/6/2005
This SAE Aerospace Recommended Practice (ARP) outlines the basic general design considerations for transport aircraft tow bars. It does not cover the requirements for tow bars intended for aircraft with a maximum ramp mass (MRW) below 8,600 kg (19,000 lb).
AGE-3 Aircraft Ground Support Equipment Committee
Environmental Control System for Light Turbo Prop2003-01-24007/7/2003
Honeywell has developed a unique environmental control system (ECS) for light turbo-prop aircraft applications. The ECS consists of two integrated systems, an Air Cycle System (ACS) and a Vapor Cycle Cooling System (VCCS). A single controller interfaces with both systems, and provides control by monitoring temperatures within the environment. The valves and fans of the ECS are then adjusted to provide the necessary control to minimise the error between the actual and set temperatures. The controller specifically provides the following functions: ACS control when selected on by the pilot VCCS control when selected on by the pilot Automatic ACS or VCCS control when selected by the pilot System self test The compressor used in the VCCS is a new generation compressor: 28Vdc power supply current Hermetical compressor technology Brush-less DC motor Analogical driving speed This paper will present the design of the hybrid ACS/VCCS environmental control system and notably its unique characteristics - the compressor and control system.
Genty, A., Saunders, A., Cimino, J. P., Rose, S.
A Parametric Study of Performance Characteristics of Loop Heat Pipes1999-01-20067/12/1999
A parametric study of performance characteristics of a Loop Heat Pipe (LHP) is presented. A mathematical model, based on the steady-state energy conservation equations, is used. The calculations are performed by varying the operation conditions (heat load, sink and ambient temperatures, and elevation) and the LHP design parameters (working fluid, transport length size, external thermal conductance of the condenser and wick properties). The results are illustrated on LHP performance curves (saturation temperature as a function of applied power). All the results are compared with a baseline configuration to analyze the effects of different parameters. Operating limits due to various constraints such as heat transport limit, capillary pressure limit and the vapor pressure limit are discussed.
Kaya, Tarik, Ku, Jentung
Aircraft TowbarARP1915B (Historical)12/1/1997
This SAE Aerospace Recommended Practice (ARP) outlines the basic general design considerations for aircraft towbars.
AGE-3 Aircraft Ground Support Equipment Committee
The Convair Flying Automobile9215668/1/1992
Goldsworthy, Brandt
Advanced Cooling Systems for Agricultural and Industrial Machines7511832/1/1975
This paper describes a number of major modifications and alterations which have the potential to improve engine cooling systems for agricultural and industrial machines. Of the passive augmentation schemes studied (packed-beds, gas/solid suspensions, and spray cooling), spray cooling is the only one which has potential for practical application, but only for intermittent use to avoid overdesign of conventional cooling systems. The active augmentation techniques considered (surface scrapers, acoustic vibrations, and electric fields) involve additional system complexity. Acoustic vibrations and electric fields are not effective enough to justify their use in augmentating heat transfer in conventional cores. Recent laboratory tests of the surface scraping technique indicate that this method is very effective for improving heat transfer to air flows. Studies of several new cooling arrangements indicate that direct contact heat exchangers and vaporization and condensation of engine coolant would probably not work as improved cooling systems. On the other hand, the following arrangements can reject large amounts of heat: tire heat exchangers, implement heat exchangers, and radiative-convective cooling panels. One or several of these arrangements could be attractive when used in combination with a smaller conventional heat exchanger.
Bergles, Arthur E., Junkhan, George H., Jensen, Michael K., Hagge, John K.
The Plessey Constant Speed Drive/Starter and Its Application to the BAC 1-11 Commercial Transport6705462/1/1967
Prior to the introduction of the BAC 1–11 aircraft, constant speed generator drives were primarily the hydro-mechanical type; i.e., the engine speed was trimmed by the use of hydraulic devices. The BAC 1–11 has introduced the Plessey CSDS, a pneumatically trimmed unit which assumes the dual role of a CSD and an engine starter. This unit is basically an epicyclic gear train which takes inputs from both the engine and a reversible roots type air motor/blower to drive an A-C generator at a constant speed. This paper will discuss the design, operation, and performance of this unique unit.
Smith, R. L
Development of Air Conditioning in Beech Airplanes6602092/1/1966
A general discussion of the problems involved in introducing air conditioning in small executive aircraft. The discussion includes: (1) early studies and hardware for “add on” package units, (2) system selection studies for small pressurized turbine powered aircraft, (3) system design including structural changes required, (4) testing, development and service experience on the Beech King Air cooling system and (5) other applications and possible future development trends.
Clay, L. B.
Airline Experience With Aircraft Engine Lubricating Oils5101531/1/1951
TAYLOR, HARRY N.
COMPARISON OF USE OF MIXED STRUCTURAL MATERIALS AND FABRIC COVERING TO ALL-METAL CONSTRUCTION FOR PERSONAL AIRCRAFT FROM A MANUFACTURING VIEWPOINT4701501/1/1947
JAMOUNEAU, WALTER C.
The INTERCOOLING PROBLEM in AIRPLANE DESIGN4402071/1/1944
A DISCUSSION of the aircraft-engine charge-air cooling problem is given here from the point of view of the airframe designer. Many of the factors which enter into the selection of the type and capacity of charge-air cooling installations are difficult to subject to quantitative analysis. Among these are problems of simplicity, maintenance, accessibility, and arrangement of the engine installation. In general, however, the difficulty of installation of the charge-air system is out of proportion to the core size. The weight increase due to the system, for instance, is in the neighborhood of five times the weight of the air-to-air intercooler core. The use of a liquid-to-air aftercooler system as opposed to an air-to-air intercooler system shows promise only in applications with liquid-cooled engines where the separation of the ultimate cooling unit from the rest of the installation is a definite arrangement advantage.
DICKINSON, HOLLEY B.
The Use of PETROLEUM PRODUCTS in AIRCRAFT4301501/1/1943
KLEIN, FRANK D.
CABIN SUPERCHARGING in Scheduled AIRLINE OPERATION4301421/1/1943
ELLINGER, R. L.
Design of Cowlings for Air-Cooled Aircraft Engines3701931/1/1937
RECENT work on cowlings for air-cooled engines has been characterized by the correlation of the cooling function of the cowl with the drag-reducing function into a rational design procedure, whereas earlier work was devoted largely to drag reduction and this was a cut-and-try proceeding. The fundamental relations between the pressures and velocities of the external and internal air flows are discussed here in their relation to the quantity of air available for cooling and the effect on drag. Experimental results are outlined, and a design procedure is indicated. It is pointed out that certain factors must be determined by the engine manufacturers in order that a rational design of cowl may be laid out. The shape of the cowling nose is not critical, and the part of the drag that is subject to control is determined by the air flow out the cowl exit. For an efficient cowling and for control of the air flow, the exit is the important part. A procedure is given for designing an efficient skirt and inner cowl which form the exit. The propeller has an important effect on the flow at low air speeds, but, in general, is insufficient to provide the necessary flow of air required for cooling on the ground. A new type of cowling providing more flow in this condition is discussed. Finally, the in-line air-cooled engine is mentioned. The cooling problem here is shown to depend on air-flow conditions differing considerably from those of the radial engine. Economical cooling is dependent on the reduction of internal losses, particularly the large turning loss at the entering side of the engine cylinders.
Wood, Donald H.
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