Abstract: An internal combustion ventilation apparatus and method for reducing the moisture content of an internal combustion engine at rest in order to prevent or minimize corrosive activity in the engine. The apparatus includes the oil filler tube and the engine breather pipe of the engine to be ventilated, as well as a blower. The blower is connected to either the oil filler tube or the engine breather pipe and directed so that air is brought into the engine breather pipe for circulation through the engine cavities, then to be exhausted through the oil filler tube. The dryer outside air displaces moisture laden air in the engine cavities. In one embodiment of the invention an engine preheater is installed on the engine for the purpose of adding heat to the idle engine and increasing the moisture holding capacity of the air being moved through the engine.

Abstract: A gasket shaped heater for placement between parting surfaces of component housings of engines, gear housings, differential housings and similar structures. The heater preheats the components to facilitate cold weather starting or operation thereof. In one form of the invention the heater is semi-permanently attached to a parting surface of the component housing and has an outer metallic surface which interfaces with the standard gasket located between the connected components. In another form of the invention, the heater takes the place of the standard gasket normally interposed between the parting surfaces.

Abstract: An improved aircraft altitude approach control device is characterized by both visible and audible indications of changes in the aircraft altitude as the aircraft descends to a landing. A transducer is provided on the aircraft which produces an output signal corresponding to the altitude of the aircraft. The output signal is converted to a digital signal and then to an analog voltage signal. A voltage controlled oscillator produces an audio frequency signal whose pitch corresponds with altitude. A further characteristic of the invention is the provision of a memory circuit in which a digital signal corresponding to a preferred landing is stored. This signal can be modified to produce a preferred or reference analog voltage signal. The actual and reference voltage signals are delivered to a glide slope meter which indicates differences therebetween. Thus, a pilot can gauge his landing approach relative to the reference or preferred landing approach.

Abstract: A preheat device for preheating an internal combustion aircraft engine having an air intake pipe connected to a cylinder head by threaded mounting bolts is configured as a replacement bolt with a zinc - plated body having a bolt head and threaded shank. The body is made of steel heat treated to grade 8 hardness and tempered at apprximately 1,050 degrees F. and had an axial bore open at the head and extending toward and into the shank. An electric heating element surrounded by a stainless steel sheath is positioned in the bore. The shank has a thread with a flat root to provide a wall thickness approximately 0.060 inch. Each cylinder of the engine is provided with a preheat device in place of a mounting bolt and the preheat devices are connected to each other by a wiring harness connectable to an external power source. When energized the heating element of each preheat device generates heat that in transferred through the screw threads to the cylinder head of the engine cylinder.

Abstract: A battery charging device is operable in conjunction with a battery heater to simultaneously heat and recharge the battery of an aircraft which has been stored under cold weather conditions. A thermostat energizes a power supply when the ambient air temperature drops below a given value. A transformer is connected with a power supply to produce an output voltage and a pair of transistors are connected with the transformer for converting the transformer output voltage to a given charging voltage which is supplied to the battery. A voltage control device including a rheostat and a voltage regulator is connected in a feedback circuit with the first and second transistors to control the transistors to produce a constant charging voltage. Thus as the battery is heated, the charging voltage supplied to the battery recharges the battery to full capacity.

Abstract: A preheat apparatus for a helicopter wherein certain critical helicopter components are preheated preparatory to takeoff of the aircraft. The critical components include the main rotor gear case, the intermediate gear case, the tail rotor gear case, the oil tank and cooling assembly and the engine gear cases. In certain aircraft, these also include the fuel control unit and the drive reduction gear case. Heat pads are installed with respect to the critical components in strategic locations and are sized and shaped to fit the component. The heat pads are connected by wiring harness that is connected to an external source of electrical power.

Abstract: An aircraft battery assembly to provide a preheated battery to facilitate aircraft operation in cold temperature. The battery assembly includes a battery housed in a battery box and having a heating jacket wrapped around it. The heating jacket is elongate and rectangular with a width less than the height of the battery and a length sufficient to wrap around the battery with vertical edges that approach one another near a quarter of the battery. The edges have grommets with eyelets. The grommets of the respective edges are laced together to secure the jacket around the battery. The jacket is comprised of inner and outer insulative layers with a heating element sandwiched between them. The jacket is very thin so as to able to readily turn the corners on the battery. The heating element is operated responsive to a thermostat sensing temperature.

Abstract: An aircooled aircraft engine is preheated prior to starting by the insertion of electric heating devices into the blind holes, normally provided for the reception of thermocouples, in the metal castings of the cylinder heads immediately adjacent to the spark plugs. The heating devices are of such size and shape that the heating devices are entirely confined in the metal wall of the cylinder casting so that when energized substantially all the heat is transferred to the castings immediately adjacent the spark plug. The heating devices are energized for a sufficient time prior to starting to generate enough heat to prevent frosting of the spark plug, prevent condensation and improve vaporization of fuel when starting the engine.