UBRARY ^TATE PLANT BOARD ^^ July 19U3 ET-212 UNITED STATES DEPART\ENT OF AGRICULTURE Agricultural Research Administration Bureau of Entomology and Plant Quarantine A HOPPER AND I^CHANISM FOR DISTRIBUTION OF BAITS Mil DUST BY AIRPUNES FOR INSECT CONTROL By Chester N. Husman, Division of Domestic Plant Quarantines Outbreaks of grasshoppers. Mormon crickets^ and white-fringed beetles in recent years have emphasized the need for adapting air- planes or autogiros to spread baits and insecticide dust in large- scale pest-control programs of emergency nature, while the most im- proved ground distilbuting machines have rendered excellent service, the extensive areas requiring application, the ruggedness and inac- cessibility of considerable portions of the terrain, the urgency of tbs need for immediate application, and the necessity for economy of operation prompted the development of airplans hcppers and dis- tribution mechanisms for application of such materials. Airplanes adapted for crop dusting were tested for these purposes, and it was determined that they could be used to advantage if a mechanism coTild be designed that would distribute materials without clogging or tunneling and spread them in an even and uniform swath. The baits consisted of bran, sawdust, rater, and insecticides, which were very difficult to distribute because of a tendency to pack and tunnel over the revolving agitators ii? the standard type of hopper employed for cotton dusting. The cryolite dust used for the control of white-fringed beetles also gave the same trouble as the wet baits. In order to control the number of pounds of bait distributed per acre, the opening on the bottom of the hopper of the cotton dusters was adjustable so that the flow of materials cculd be regulated by dev^reasing or increasing the size of the aperture. This some- timss caused clogging, was difficult to adjust to an even flow, and contributed to mechanical breakdowns and loss of time. It was neces- sary, therefore, to redesign the mechanism or to construct devices which would eliminate the shortcomings of existing eqvdpment. The latter course was considered to be more practical. Mechanical Principles Preliminary consideration of various adjustable mechanical devices designed to apply baits or dusts from airplanes suggested the adaptation of certain essential principles without structural changes in the plane, including (1) a hopper, with smooth walls as perpendicular as practical to permit materials to settle to the bottom, from which they would be fed out in application; (2) an endless drag-link chain conveyor, the effective portion of vhich would revolve . over the false bottom of the hopper upon which the materials bear, to withdraw desired amounts by means of suitably sized and spaced angle-metal bars, connecting the drive chains, spaced apart the full width of the hopper; (3) an opening, or throat, with an adjustable door at the lower front of the hopper, through which the conveyor would deliver desired amounts of materials; (4.) an open-ended enclosure or venturi tube parallel to the airflow, beneath the hopper and below the fuselage, into which materials would be delivered through the hopper door (controlled by the pilot from the cockpit) and from which they would be driven by the rush of air beneath the plane and distributed in its wake; and (5) an outboard wind-driven oropjeller, adequate to furnish power to operate the distribution mechanism through a reduction gear, with a brake controlled from the pilot's seat. These principles have been incorporated in the described construction and are set forth in the attached drawings, which show the installation, mountings, and relative position of the component parts. Specifications and a list of materials necessary for the construction of the various parts are hereinafter presented, Approuriate dimensional alterations wo\ild permit adaptability of this type of hopper a. id distribution mechanism to any plane or autogiro, depending on its size, design, load capacity, speed, and other factors. The hopper described herein is of 29 cubic foot capacity for installation in a biplane powered by a 285 horsepower engine with cr\iising speed of 90 miles per hour, and which will carry a pay load of 984- poiinds on the take-off. Mounting of Hopper Unit The hopper is mounted between the fire wall and cockpit, taking the place of the frcnt cockpit, at the center of gravity of the plane, as shown in drawing 3. The center of gravity varies with different types of airplanes. To insure safety in flight and permit licensing of the craft by the proper authorities, the hopper should be installed by persons thoroughly acquainted with the mechanics of aircraft. The hopper is attached to the top longerons try means of l|- inch aluminum alloy tee sections, and the bottom rests on the loiNer fuselage members with wood strios between, which thereby clamp the hopper and conveyor xinit to the lower fuselage members as shown in drawings 3 and 5. The hopper is constnacted of .065-inch 2 SO aluminum and is bolted to the top cowling of the same material, vvliiph forms part of the hopper, as shown in drawings 1 and 2. The pov/er unit, including the small propeller and reduction gear, is mounted on a bracket which extends frcra the lov/er longeron to the top longeron and is connected to the outside of the fuselage by clamoing the bracket to the longerons, the latter being protected with l^inch wood blocks and l/l6-inch vraod strips between the clamps and members, as shown in drawing 4. There are no parts of the hopper construction attached to the fuselage without intervening wood or rubber to protect the fuselage raembers. The hopper is so installed that, as the weight of its contents changes, the center of gravity is still within the range for which the airplane is approved. Specifications for Hopper Unit Construction and Installation Hopper . — Hopper to be made of .065-inch 2 SO sheet aluminum, taking advantage of all suitable space in the fuselage, the bottom of the hopper to be approximately the width of the bottom of the inside of the fuselage (drawings 1 and A) - Hopper to have an adjustable door directly over the outlet end of the drag-link conveyor so as to regulate the amount of material fed by the conveyor (ditiwing 3). Hopper to be dustproof . Hopper walls to be supported with 1^- by l/8-inch angle aluminum alloy braces (drawings 1, 3, 4, and 5). The hopper door to be 27 by 37 inches and constructed of .065-inch 2 SO sheet aluminum (drawing 2). The cowling to be well braced around the door (drawing 2) . Drag-link conveyor. — As shown in drawings 6 and 7. The drag links to be of 1/3- by 1-inch 17S-T angle aluminum alloy, spaced 4. inches apart. The conveyor chain to be No. 32 malleable iron, com- plete with right and left A-1 attachments. The conveyor to be as near as possible the full width of the bottom of the hopper (draw- ings 6 and 7) and driven by four No. 32 eight-tooth sprockets mounted on 3A-inch shafting. Sprockets to be turned down and made as light as possible. Shafting to be supported by dustproof rubber pilloir block ball bearings, 3A-inch, ivhich should be mounted so that adjustments can Jt)e made on the drag-link conveyor (dranfings 6 and 7) . Felt washers to be mounted between bearings and conveyor box. Conveyor box to be made of •065-inch aluminum braced with 1^ inch aluminum alloy. The hopper floor under the endless drag-link top chain, as shown in drawing 6, to be made of .091-inch alumintim alloy with a l^-inch tee section of the same material for support. The conveyor unit to be bolted to the bottom of the hopper, thereby clan^jing the hopper and conveyor unit to the lovrer fuselage members, as shown in drawings 3 and 5. Fuselage members to be protected by wood, fabric, or rubber. The hopper door to be full width of hopper with an opening of at least 6 inches. Door to be made of .187-inch 2 S l/2 H sheet aluminum. Door to be dustproof mdien closed (drawings 6 and 7). Venturi tube . — The venturi tube to be adjustable and full width of conveyor box. Tube to be made of .06^-inch 17S-T aliominum alloy, well braced with l/2-inch channel iron (drawings 1, 3, and 4) • Power unit . — Power to be provided by an 18-inch (overall) propeller, connected to 4-8 to 1 gear reducer, mounted on side of fuselage. A brake to be mounted on propeller. Lining and brake drum to be 1 inch in width. Brake to be connected by a 3/l6-inch cable to the hopper door control. Twelve-tooth, No. 41 sprocket to be mounted on drive shaft of reduction-gear box. The 24-, 30- , and 45-tooth No. 41 sprockets are to be used for varying speeds on the drag-link conveyor shaft (drawings 2 and 4). The gear box mounting bracket to be clamped to the top and lower longeron (draw- ing 4). Controls . — Controls for hopper door and propeller brake to be installed in cockpit accessible to the pilot (drawing 3) • Fuselage and wings . — All openings and outlets, such as those urtiere controls and cables enter fuselage and wings, should be covered or protected by socks to prevent the entry of dust into cockpit or interior of wings. - 5 - List of Materialfl Hopper Unit 1 72" X 36" X .039" 2 SO sheet alumiimn 2 60" X 36W X .065" 2 SO sheet aluminum 2 12» X 36" X .065" 2 SO sheet aluminum 2 ^ft" X 36" X .065" 2 SO sheet alum.Lnum 1 36" X 28" X .065" 2 SO sheet aluminum 1 20» X 1^ X 1/8" Aluminum alloy T section 2 20' X 1^' X l/8" Angle aluminum alloy 1 6' X 1" Aluminum hinge 2 12» X 2^» X .091" ........ 2 S 1/2 H aluminum alloy sheet 1 15 ' X 1/2" Channel aluminum 660 l/2" #8-32 cadmiuitt-plated bolts and nuts 200 3/4" #10-32 cadmium-plated bolts and nuts 1 25' of 3/4" channel rubber edging 3 \utomobile hood hooks or trunk latches Conveyor Unit 1 27" X 9" X 3/16" Alumin'om alloy plate 1 48" X 43" X .065" : 2 SO sneot aluminum 4 10» X Ij" X Ij" X 1/B". . . ... .Uuminiira alloy angle 1 24" X 26" X .o91» ........23 l/2 '' sbeat aluminum aU^^y 2 12' X 1" X l/2»» X 1/n" . - . . . . AlumimiiT! :''^ay ancle 4 8-tooth ^"32 sprockets > ■ ' i 10' *j'32 malleable detao^iade -;i.'.:n - - 20 A-1 R attachirenta fox "^2 cr.- n. 20 A-1 L attachments for i^32 chain 5 3/4" rubber pillow block ball b*^aring 4 ^3 tapered pins 50 yib» X 3/4" aircraft bolts and castle n>its 30 3/16" X 1" aircraft bolts and castle nuts 1 r>" X 26" X 3/16" Aluminum alloy plate 200 )!i^O-32s cadmium-plated bolts and nuts 1 ^" X 3/4" 0. D.'x 3/32" ^rall thickness aircraft steel tubing 1 :j,» x 3/4" 0. D. cold-rolled shafting r Unit 1 48 to 1 sear reducer 1 18" overall wood propeller; 2 blade 1 12' x 3/16" flexible cable 1 3' X 1" X 3/32" Molybdenum steel 1 Stub shaft to be made to hold propeller on gear box drive 1 4" X 1" flat pulley for brake drum Power Unit (Continued) 1 12" X 1" steel brake band 1 12" X 1" brake lining 1 12' X l^w X .035" streaalined seamless stesl aircrc.ft tubing 1 3/16" plate 6" x 6" to hold brake assembly U 1/2" X 1^' bolts and nuts 1 12-tooth sprocket #43. - 7/8" bore 1 2ii-tooth sprocket #41 - 3/4" bore' i 30-tooth sprocket #41 - 3/4" bore 1 45-tooth sprocket #41 - 3/4" bore 1 6' #41 roller chain 1 Half link for #41 roller chain 1 Connecting link for #41 roller chain Venturl Tube and Control 1 24" X 26" X .0^.9" 2 S 1/2 H aluminum alloy sheet 1 48" X 12" X .091" 2 S 1/2 H aluminum alloy sheat ^ lb. alumimun rivets - 3/32" x l/4" 1 4' X 1/8" X 3/4" strap iron 1 9' X 3/4" X .065" wall - aircraft tubing 1 12 « X 5/8" X .065" wall - aircraft tubing 5 1/4" X 3/16" clevis and pins 1 Rubber handle grip 30 1" #8-32 aircraft bolts and nuts 1 Aircraft pulley - 2" x 17/64" 1 4|" turn buckle 4 3/8" tie rod terminals - threaded clevis type QL UJ a. 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