US1419180A - Aeronautical propeller - Google Patents

Description

P. THOMSON AND M. J. WHELAN.

AERONAUTICAL PROPELLER. APPLICATION FILED DEC. 15. 1917.

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PROCTER THOMSON AND MICHAEL J. WHELAN, OF MUSKEGON', MICHIGAN, ASSIGNORS TO THE BRUNSWICK-BALKE-COLLEND CORPORATION OF DELAWARE.

ER COMPANY, OF CHICAGO, ILLINOIS, A

AERONAU'IICAL PROPELLER.

ntense.

Specification of Letters Patent. Patented June 13, 1922.

Application filed. December 15, 1917. Serial No. 207,282.

To all whom it may concern:

Be it known that we, PROCTER THOMSON and MICHAEL J. WHELAN, citizens of the United States, residing at Muskegon, in the county of Muskegon and State of Michigan,

have invented certain new and useful Improvements in Aeronautical Propellers, of which the following is a specification.

This invention relates to aeronautical projpellers and has for its object the elimination of the inherent disadvantages resulting from the common mode of constructing propellers and the provision of a propeller of the requisite strength, rigidity and lightness which presents a smooth, indurated, weatherproof surface. l

Further objects and advantages of our invention will be better understood by reference to the following specification when read in connection with the accompanying illustrating the preferred embodiment thereof, in which Fig. 1 is a side elevation of an aeronautical propeller of the well known form and construction Fig. 2 is a side elevation of a propeller according to our invention;

Fig. 3 is an enlarged sectional view of the structure illustrated in Fig. 2, and

Fig. 4 is an enlarged sectional view through the hub of the propeller.

Aeronautical propellers have heretofore been constructed by superposi'ng a plurality of layers or laminations of some suitable hard wood, the layers being secured together by an adhesive such as glue. From the block thus formed the propeller is shaped. Even when the utmost care is exercised in building up the blocks a large proportion of the propellers will be rejected because of imperfect joining of the layers which becomes apparent only after the propeller is partially or wholly shaped. A large amount of material and labor is thus wasted. Moreover propellers apparently perfect when finished frequently develop flaws after being used for a short time. These flaws permit the air to enter between the layers of temperature and humidity to which propellers are subjected in use sooner or later afi'ect the wood and glue and increases the liability of wood propellers to fail. Finally the constant friction of the air on wood propellers quickly wears the surfaces to an extent which ruins them after a short interval of use.

,We propose to overcome these and other inherent defects of wood propellers by pro viding a core and enclosing the same 1n a hard, dense, impervious shell of a suitable weather proof material which is integrally united with the core. We have found that hard rubber is a very desirable material for this purpose because it can be vulcanized to the core and integrally united therewith,

propeller is reduced to a minimum, thereby saving material and labor which more than offsets the slightly increased cost of our construction. A safer and' more dependable propeller is thus provided.

Referring to the drawing, we have illustrated in Fig. 1 for purpose of comparison a common wood propeller made up of a plurality of layers 5 of wood joined by means of glue.

In Figs. 2, 3 and 4 we have illustrated our propeller which consists of a core made up of a plurality of layers 6 of wood secured together by means of glue and shaped to approximately the finished form of the propeller. The surface of the wood is preferably left rough, thus eliminating the necessity and expense of finishing, and also permitting a better bond between the wood and hard rubber shell 7.

The shell is applied by arranging a layer of uncured rubber composition about the core which is then disposed in a suitable mold of the shape and contour of the finished propeller.- By subjecting the mold to pressure and heat in the well understood manner the rubber is vulcanized and inte rally united with the core. Upon remove from the mold at the completion of the vulcanizing operation the propeller may be polished and it is then ready for immediate use.

From the foregoing it will be readily understood that we have perfected an aeronautical propeller which presents numerous advantages over wood propellers and that various changes may be made in the shape, dimensions and relative thickness of the core and shell Without departing from the spirit and scope of the invention or sacrificing any of the advantages of the invention, the form hereinbefore described being merely the preferred embodiment thereof. While we now prefer to use hard rubber to PROCTOR THOMSON. MICHAEL J. WHELAN.

Witnesses J. O. MATTESON, D. VA K, Jr.

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