US2317019A - De-icing device for airplane propellers, wings, and the like - Google Patents

Description

April 1943- J. D. ALTEMUS 2,317,019

DEICING DEVICE FOR AIRPLANE PROPELLERS, WINGS, AND THE LIKE Filed Jan. 27, 1941 w l VENTQR1 MATTORNEY.

Patented Apr. 20, 1943 DE-ICIN DEVICE FOR AIRPLANE PRO- PELLERS, WINGS, AND THE LIKE James Dobson Altemus, Roslyn, N. Y.

Application January 27, 1941, Serial No. 376,125

3 Claims.

This invention relates to the prevention of ice formation on the propeller wings and other vital parts of airplanes, more especially the leading edges thereof and depends for its efficiency upon the utilization of radiant heat for maintaining the edges or areas which it is desired to protect against ice formation at a temperature sufficiently above the freezing point of water to prevent rain or water vapor from freezing thereon, as well as to effectively melt hail or sleet particles the instant the same impinges or settles upon such heated edges or areas.

It is well recognized that the range of tcmperatures at which such ice formation occurs on the propellers and wings of airplanes is very limited and except under extraordinary atmospheric conditions does not exceed about F., but heretofore, due to the intensive cooling effect of the rapidly flowing air stream to which said blades and m'ngs are subjected in flight, the problem of protecting such areas of the airplane against ice formation has failed of successful solution. Since radiant heat emanating from a source of infrared rays is however remarkably insensitive to defiection or cooling by the air stream which flows over the propeller blades or wings when the plane is in flight, even at high speeds, and since the temperature range, as above stated, at which ice formation occurs is extremely limited, my improved device, which as above stated utilizes radiant heat rays of the infra-red type, serves to effectively solve this hitherto baiiling problem of ice formation.

My invention is fully described in the following specification and drawing forming a part thereof, in which latter- Figure 1 is a fragmentary plan view of an airplane equipped with my improved device and Fig. 2 is an enlarged fragmentary, detailed plan view, partly in horizontal section, showing the front end of the fuselage and a portion of the propeller.

Referring to the drawing and construction shown therein, the reference numeral I designates the fuselage of an airplane equipped with the aforesaid device, 2 the wings thereof, 3 the leading edges of the wings, l the hood of the engine compartment, 5 the engine, 6 the propeller shaft, 1 the hub thereof, 8 the propeller blades, 9 the propeller nose and ill the hub-cap.

Referring to Fig. 2, it will be observed that the hub-cap is equipped with oppositely disposed infra-red lamps I5, equipped with reflectors it generally of parabolic curvature, concentrating lenses H, at whose foci such lamps are respectlvely positioned, and cover glasses l8, which latter conform to the curvature of the hub-cap. The numeral l9 designates the retaining strips which are disposed marginally of the apertures in said nose 9 in which the cover glasses are mounted and the numeral 20 designates the lead wires which connect the lamps to a source of current as a storage battery or generator. The lenses I! serve to project upon the leading edges of the propeller blades concentrated infra-red heat rays, as indicated by the reference letter a, which rays are substantially unaffected by the rapid, rearwardly flowing air stream developed by the forward flight of the plane, and these rays serve to maintain the temperature of such leading edges of the propeller blades substantially above the freezing point when conditions are such that ice would otherwise form or collect thereon.

Similar infra-red heating units I5, whose refiectors l6, lenses and cover glasses are of substantially identical construction with the aforesaid units, except for appropriate variation as to size, are mounted in the fuselage and are adapted to likewise protect the leading edges of the wings by virtue of the concentrated beam essentially composed of infra-red heat rays b projected thereon from such units.

From the foregoing, it will be apparent that the aforesaid device is peculiarly adapted for effectively preventing ice formation on the leading edges of propeller blades and wings of airplanes. Moreover, if metal propeller blades are employed then, if the heat generated by the lamps I5 is of sufiicient intensity to prevent the formation of ice on the leading edges thereof, the heat conductivity of the metal of the blades will be such that the entire blades will also be protected from formation of ice thereon.

From actual tests made under conditions simulating that of an airplane in flight, it has been demonstrated by applicant herein that with a relatively small consumption of current it is possible by utilizing infra-red rays or so-called radiant heat which is essentially undefiected by the rapidly moving air currents developed by the flight of the plane, to maintain the leading edges of propeller blades and of the wings substantially above the freezing point (32 F.) even though the plane is travelling at high speeds and high altitudes whereas on the other hand, due to the ready deflection of heated air currents, it is impossible to obtain any appreciable de-icing action on propeller blades of wings'lf it be attempted to utilize hot air projected by a blower for example upon the leading edges of the plane or propeller measured in centimeters.

in lieu of a projecting undefiectible radiant rays thereon such as herein described.

As is well known, radiant heat emanating from hot solids and gases constitutes essentially electromagnetic waves of substantially invisible infrared rays whose wave lengths range between those of the rays of the red end of the visible spectrum, the various visible rays whereof are usually measured in microns or even millimicrons, on the one hand, and the wave lengths of the so-called wireless or hertzian waves which latter are usually These infra-red rays can be reflected or refracted the same as the visible rays of the spectrum. Ordinary glass, however, is substantially opaque to the passage of these infra-red rays. However, modern glass makers have developed glasses of special composition which have a relatively low absorption index for these rays. Also substances such as sylvin and fluorite effectively transmit these infra-red rays. Moreover, quartz, in thicknesses of a centimeter or at most a few centimeters, effectively transmits these infra-red rays, especially those whose wave length exceeds 70 microns, although quartz, is highly absorptive of infra-red rays of a wave length approaching that of the rays of the visible spectrum.

In view of the aforesaid characteristics of these infra-red rays, the concentrator lenses H and cover glasses I8 are composed desirably of sylvin, fluorite, thin sections of quartz, or special glass capable of eflectively transmitting infra-red rays instead of ordinary glass such as employed for cheap reflectors of visible light rays.

Various modifications within the scope of the heat appended claims may be made without departing from the spirit of my invention.

Having thus described my invention, I claim:

1. The combination with the supporting plane and propeller of an airplane, of a source of electromagnetic infra-red radiant heat rays carried by the airplane and means for directing electromagnetic heat rays, emanating from said source, on the leading edges of at least one of the propeller and supporting plane members said means including a concentrating lens disposed in front of said source composed of a material which is highly transparent to infra-red rays developed by such source.

2. In an airplane, the combination with a supporting plane and a propeller, of a plurality of separated sources of radiant heat energy mounted on said airplane and one of said sources being located in immediate proximity to the hub of said propeller and a reflector element disposed at the rear of each of said sources and ray-concentrating means disposed in front of each of said sources, said concentrating means being highly transparent to infra-red radiant heat waves developed by said sources and arranged to project said radiant heat waves against the leading edges of at least one of the supporting plane and JAMES DOBSON ALTEMUS.

Images