New Generation De-Ice Systems
Over the past several years, Villinger R&D has developed proprietary, elastic semi-conductive polymers that can be applied as a thin coating (< 0.2mm) to a variety of parts and components, yielding a heat-able layer with a surface density of approximately 150 g/m2 or less. The coating is heated electrically using either AC or DC voltage and has a positive temperature coefficient (PTC), which yields a coating that is temperature self-limiting and will not experience damaging “hot spots” encountered by traditional resistive heaters. The coating sheet resistances can also be chemically tailored to obtain values ranging over several orders of magnitude depending on the requirements of the application.
The coatings are extremely damage tolerant and can readily continue to operate after being punctured repeatedly. Finally, voltage can be applied across the entire surface using flexible, low profile electrical buses on either side of the coated area, enabling extremely simple wiring configurations that can be laid out in a multitude of geometries to fine tune desired power densities.
Heat-able coatings developed by Villinger R&D
- Have low energy consumption
- Are easily applicable as a paint on 3D and twisted surfaces
- Will not affect the aerodynamics of the vehicle, as they can be integrated fully into composite structures
- Are thin and lightweight
- Are easily applicable to a variety of substrate materials with excellent adhesion properties
- Will continue to operate despite damage and can be readily reapplied if damage occurs
- Will not affect the integrity of structural components
- Employ a self-controlling heating technology that provides even temperature over the complete surface covered, preventing “hot spots” typical of resistive heaters
- Are ideal for use in composite structures due to distributed heating with no “hot spots” that may cause damage
- Are elastic and can sustain elongations and vibrations representative of rotorcraft operation
Specifications of Villinger’s heat-able coatings:
- System thickness: < 2/10 mm
- Overall System weight: < 150 g/m2
- Temperature: (active / passive) up to 180° Celsius
- max. Power Density: 12 W / cm² / 77 W / inch²
- Variable Voltages: (from 6V up to 690V AC or DC)
- Heating Systems can operate with and without ECU (Electronic Control Unit)
The main features of Villinger’s heat-able coatings are therefore:
- Safe by design
- High damage tolerance
- Improved flying performance
- Fuel and energy savings
- Performance superior to state of the art technology (like de-icer pads)
- Low power consumption
- High environmental and structural durability
- Proven performance
- Flexible and easy application
LDI systems are safe by design
An extremely useful property is that LDI uses Villinger’s heat-able coatings which have a positive temperature coefficient (PTC). In such materials the electrical resistance increases with increasing temperature. As a result, a PTC coating can be designed to reach a maximum temperature for a given input voltage, since at some point any further increase in temperature would be met with greater electrical resistance. As a result, PTC coatings are temperature self- limiting and prevent heater failure due to “hot spots” that can quickly develop with conventional heaters. Villinger coatings also exhibit smooth, distributed heating over the entire energized zone. Because Villinger coatings are temperature self-limiting, on many occassions there is no need to thermal sensing which may be required using conventional de-icer pads, thus further reducing system complexity. It should also be noted that Villinger designs the polymers to have only mild resistance changes with varying ambient temperature, primarily to ensure sufficient resistance at lower temperatures to prevent extreme power draw by the system when initially activated.
PTC characteristics of Villinger’s heat-able coatings are tuned to operate at low or high temperatures in order to reduce energy consumption when initially activated (X axis: temperature, Y axis: resistance in Ohms).The heat-able Villinger coatings have in-built PTC characteristics, which protect them from overheating, runaway effects and development of hot spots.
IMPROVED AIRPLANE PERFORMANCE
LDI systems provide improved flying performance
Villinger’s ultra thin heat-able coatings can be implemented into or onto a structure with no aerodynamic panelties which results in highly improved aerodynamics and improved airplane performance over many conventional ice protection systems.
Test Flights show significant airplane performance improvement over same Propeller with conventional Ice Protection System
Hybrid Thermo Electric
Ice Protection System
High efficiency – low energy requirement
LDI energy efficient electro thermal Ice-Protection-System relies on the combination of a permanently activated heated parting strip at the stagnation point of the airfoil, so called Anti-Ice Zone and periodically activated De-Icing Zones which are located on the upper- and lower side of the stagnation point covering the area of the leading edge where in flight ice may form.
When flying in icing conditions the permanently activated Anti-Ice Zone divides the ice at the stagnation point in an upper and lower area at the leading edge which allows simple shedding after periodically activation of the de-ice zones. For additional energy efficiency de-ice zone get overall this electro thermal Ice Protection System requires only a fraction of the energy compared to conventional electro thermal Ice Protection Systems and makes it suitable not only for large but also for small or low powered aircraft including UAV and piston aircraft.
Ice Protection Systems
Rotors and Propellers
LDI Rotor blade Ice Protection Systems are built in a much simpler, thinner, and more robust way in comparison to conventional systems. The systems may be layed out so there is no temperature sensoring necessary on the blade which aditionally reduces complexity and failure rate
LDI Rotor blade Ice Protection Systems may be fully integrated in the composite structure for improved aerodynamics and light weight.
The power consumption of the LDI system is considerable lower compared to state of the art rotor heating systems (Electro-thermal Graphite Heaters behind 0.04” thick stainless steel versus Villinger heat-able coating).
& Quality Control
Together with MT-Propeller icing tunnel testing in the RTA icing tunnel on aircraft rotating propellers were performed. The extensive testing in aircraft propeller ice protection were done according to FAA / EASA requirements. Tests in various icing conditions were done to compare the LDI de-icing system with conventional de-icer pads. The result was that LDI de-icers are superior compared to conventional systems - using the same area and the same power.