AH _. ^. UNCLASSIFIED UNCLASSIFIED. if U* ARMED SERVICES TECHNICAL INFORMATION AGENCY ARLINGTON HALL STATION ARLINGTON PDF

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UNCLASSIFIED AH _. ^. Rep-iaduced if U* ARMED SERVICES TECHNICAL INFORMATION AGENCY ARLINGTON HALL STATION ARLINGTON 12. VIRGINIA UNCLASSIFIED NOTICE: When government or other drawings, specifications
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UNCLASSIFIED AH _. ^. Rep-iaduced if U* ARMED SERVICES TECHNICAL INFORMATION AGENCY ARLINGTON HALL STATION ARLINGTON 12. VIRGINIA UNCLASSIFIED NOTICE: When government or other drawings, specifications or other data are used for any purpose other than In connection with a definitely related government procurement operation, the U. S. Government thereby incurs no responsibility, nor any obligation whatsoever; and the fact that the Government may have fonulated, furnished, or In any way supplied the said drawings, specifications, or other data is not to be regarded by ioplication or otherwise as in any manner licensing the holder or any other person or corporation, or conveying any rights or permission to manufacture, use or sell any patented invention that may in any way be related thereto. i N» J Project NY 112 OOU-U Technical Note N-27U 27 Septenber MM riii COPY» 10 f ih ' (M M .- - C. Ratwrn t* r»_ 1 AfTIA AILINOTON HAll STATION i- CO POWERED ARCTIC CARGO TRAILER OPERATIONAJ TESTS IN SAND, MUD, AND SNOW ARIINOTON U, VIMINIA Attai TlUt ^Oi ^ S. J. Weiss K. Yaoamcto D. Taylor,,.;i USE ONLY ^ ;; FEB 1 0 1? 1961 Been u U.S. Naval Civil i4».gineertng RMMVCII and Evaluation Laboratory Port Hueneae, California - I- OfrWAL USE ONLV SUMMARY An experimental Arctic Cargo Trailer of 15-ton capacity was developed by the Laboratory tc negotiate rough and unstable arctic terrain in avmbber aud vinter. Its purpose Is similar to the 15-ton capacity, military-type, full-track cargo trailer, but It has the added features of dual tandem pneumatic tires, removable tire-tracks, and a special, powered universal Joint through which the trailer is powered by the take-off at the rear of a prime mover tractor. V'hen powered, the tractor-trailer combination has a road speed of 21.6 ft/min. The trailer was tested in mud and sand at Port Hueneme, California, and in mud and snow at Fort Churchill, Canada. It has demonstrated considerable ability in sand, mud, and snow. ^ L Oi. lolal USE ONi INTRODUCTION Cargo hauling operations In the Arctic, as experienced In the Naval Petroleum Reserve No. k, have shovn the need for an Improved cargo trailer«existing tracked cargo trailers are considered to have United utility in arctic regions. Their use In the thav season 1» restricted by high ground pressures and by low towing speeds in all seasons, especially when transporting heavy loads. The 20-ton Atbey trailer has a ground pressure of 28 psl, and the 13 ton trailer 16 pel. These ground bearing pressures are much higher than those of the normal towing tractor which is usually around 10 psl. In November 1950, the Bureau of Yards and Docks assigned Project NY to the Laboratory for the development of an arctic cargo trailer, similar to the At'ney wagon, and sultaole for handling heavy cargo. The desired characteristics were a payload capacity of 15 to 20 tons, ground pressure of one to two psl, and capable of being towed at 15 mph. DEVEL0H4ENT AND FABRICATION The Laboratory prepared schematic sketches of a proposed Arctic Cargo Trailer, (see Figures 1 and 2). The schematics show an existing D8 Caterpillar tractor with a special power take-off, which is coupled through a universal Joint to a gear train in the proposed trailer to drive the tracks. When the power take-off is in gear, the regular tractor transmission is not used. The FTC drives both the tractor and the trailer at a road speed of 21.6 fpm. The trailer is powered to provide additional tractive effort in difficult terrain, where the tractor alone would normally slip stall. The schematics and desired characteristics of the proposed trailer were sent to several contractors for submittal ol proposals for design and fabrication of a prototype unit. A contract was awarded la April 1950 to Cook Bros. Equipment Company for a trailer with the following specifications. 1. Bogie Type: Dual chain drive. Single point suspension. 2. Axle Spacing: 56 3. Axle Capacity: 20,000 lb each, 2 axles. otünn [ CiAL USE ONIV it«wheels: 5. Tires: 6. Tread: 7. Over-all Width: 8. Brakes: 9. Jackshaft: 10. Sprockets: 11. Drop Gear Case: 12. Body Type: 13. Body Size: lh. Body Stabilizers: 15«Draw Bar Support: 16. Paint: 17«Hub Spacers: 18. Weight: 19«Deck Loading Height: 20 x 10.00, 10, 11 l/u B.C., 8-7/8 dish, 17-3A spacing. Wheel No. WE-6655O-B, Budd type. IU.00 x 20, 12 ply, tactical 8U-15/16 center to center of duals /8 outside to outnlde nf dual tires (with tires and wheels described in items U and 5 above). 16-1/2 x 6 with 3A block lining. Mechanical type with 9 B.W. Diaphragms and Slack Adjusters. Double reduction ratio Cook Bros. D-160-A. 19 teeth drive, U3 te »th driven, 1-3A pitch, mud and snow type, ratio Ratio 5»66; which combined with 9«02 differential ratio and 2.26 sprocket ratio gives a full gear ratio of 115«38 to produce a road speed of 21.6 fpm. Stake. Wood and steel construction with removable ends and sides, hardwood floor, and steel skid strips. 15'-0 long x 9'-10 wide with S'-O stake sides and ends. Mechanical-type manual operation and control. Manually adjusted type International Orange Industrial, two coats. Wood portion of the trailer body impregnated with a good quality of commercial preservative. One set of four 1 -thick bub «ipacers, and the required longer wheel studs, supplied for installation when standard tire chains are applied to the tires. 12,U00 lb (without Powered Universal Joint or tire tracks). ^2 The powered universal Joint was designed at the Laboratory. This item and the tire tracks were purnhnoe;» separate iron the trailer... jit 31.1 1 - - ul The complete Arctic Cargo Trailer was fabricated In accordance with the following contracts: Contract No. NI6OS-U755 Ant. $36, Prototype Wheeled Cargo Trailer Cook Bros. Equipment Co. Los Angeles, California Issued: 3 April 1951 Delivered: 5 June 1952 Contract No. Nl60B-8i485 Amt. $ U,675.0O Powered Universal Joint Engineering Products Co. Los Angeles, California lüsued: 19 March 1952 Delivered: 9 February 1953 Contract No. Nl60s-8W»7 Amt. $ 1,!*56.00 Galanot Tire Tracks, 2-30 wide, single rov connectors Galanot Track and Machine Co. Alliance, Ohio Issued: 19 March 1952 Delivered: 17 December 1952 Contract No. Nl608.lM*53(p) Amt. $ 2, Galanot Tire Tracks, 2-38 wide, double rov connectors The Union Chain and Manufacturing Co. Sandusky, Ohio Issued: 20 November 1952 Delivered: 15 January 195l* (This set of tracks was used In the tests at Fort Churchill, Canada.) In addition, the following units completed the tractortrailer assembly: Caterpillar D8 Tractor with Dozer, Ser. No Caterpillar Tractor Company Peorla, Illinois Power Take-off Transmission CW 2U0-A1, Ser. No. 118 Wood Manufacturing Company North Hollywood, California Morse Formsprag Over-running Clutch No. FS-700 Morse Chain Company Detroit, Michigan Prior to the preliminary tests of the tractor-trailer unit, the over-running clutch was installed between the ( i blal UJE OHLY trailer drop gear case and 'axle by the Laboratory shops to eliminate back driving of the Universal Joint when the trailer is not powered and is towed forward. In reverse and unpowered, back driving of the Universal Joint is accepted in the protot ype. Figures 3 through 6 show various parts of the tractortrailer unit prior to prejiniinary tests. CHARACTERISTICS OF TIE ASSEMBLED TRACTOR TRAILER UNIT The road speed of the unit is 21.6 fpm (.25 mph) when power is applied to the trailer and tractor through the power take-off. The unit can travel at all forward speeds provided by the tractor transmission when the trailer IP not powered. When the unit is in reverse, power cannot be applied through the power take-off, so that the tractor transmission speeds are used. However, reverse ground speed is to be held to a minimum because the Powered Universal Joint, which normally turns over at 212 rpm, can be back-driven by the trailer track motion at speeds up to 2000 rpm. The tractor ground bearing pressure with dozer and power take-off installed is about 10.3 pol. The trailer with 15-ton load has 13«0 psi ground bearing pressure using the 30 wide Galanot tracks, and 10.0 psi using the 38 vide tracks. The Powered Universal Joint transmits torque only. All axial forces are carried by the towbar connection between the vehicles. TESTS Preliminary tests were made in comparison to the performance of a 15-ton Athey wagon. First on prepared sand slopes at the Military Training Area, Construction Battalion Center, Port Hueneme; then in the mud of a tidewater slough near the Laboratory Equipment Compound at Point Mugu. Results of these tests appear in Appendix A. Winter tests of the trailer were conducted at Fort ChurchiH Munitoba, Canada, by the U. S. my Corps of Engineers Climatic Field Test Team under the supervision of a Laboratory engineer. The raeraorandura of pro :edure for these tests and the results are in Appendix B. ' ' ''^ ' ' IAL USE ONLY The summer tests In tundra (muskeg) vere performed b the Corps of Engineers Climatic Field Test Team. Their report with a supplementary analysis of the ground at the test site by a group from Cornell University are given In Appendix C. CONCL' ilons The 15-ton Arctic Cargo Trailer Is Inferior to a 15-ton Athey Wagon when used as a towed unit. When powered; It outperformed rhe Athey Wagon In negotiating sand and mud, over slopes and obstacles. The unit demonstrates considerable ability In snow. It Is also able to negotiate muskeg which la Impassable when the trailer Is used as a towed unit. Side slippage of the Galanot Tire Tracks on side hills and on turns Is partially caused by the track connectors being unsuitable for use with the rounded tread of the Tactical Cross Country Tires. The single powered speed of 21.6 fpm Is considered unsatisfactory. RECOMMENDATIONS In the future, If a review of requirements Indicates there Is sufficient Justification for further development of the Arctic Cargo Trailer, the following programs are recommended for consideration: Minimum 1. Decrease internal rolling resistance of trailer, when towed, by providing means to disconnect the power train from the trailer wheels. 2. Provide the ability to transmit power to the trailer at two road speeds,.25 and 1.6 mph. 3«Provide a tire track that will not be susceptible to side slippage on the wheels (change of tire section could be solution). ' t,, loial USt ÜULT Maximutn! Develop a povered trailer that would be In synchronization at all speeds of the transmission of the povering tractor. 2, The trailer vould be tracked (no tires)«use of Caterpillar track and suspension components for ';he trailer running gear are suggested to insure comparable service life of the tractor and trailer. UfrlClAL U5 t öhlk OFFICIAL üst ONLY APPENDIX A REPORT OF PRELIMINARY TESTS ON ARCTIC CARGO TRAILER 1 December 1953 MEMORANDUM Project YD REPORT OF PRELIMINARY TESTS ARCTIC CARGO TRAILER by S. J. Weiaa Comparative tests in sand and mud vere conducted with the experimental Arctic Cargo Trailer and the 15-ton Athey Wagon daring the period 5-12 November 1953» The sand teats were condu-ted on the prepared slopes in the Military Training Area while the mud tests were performed adjacent to the slough near the equipment compound at Point Mugu. Both trailera were coupled to D-8 Caterpillar Tr.^tora (Figureö 9 and 10)«The sand tests on the experimental unit were performed both with and without the Galanot tire tracks. The mud tests were carried out with tracks installed. Tire pressure of the expcrlmentol unit was 35 psi. The tracks on both the Athey wagon and the experimental trailer were 30 wide. The sand tests conducted on the 25^ prepared slope (see PlgUN 11) gave the following results: Test Unit Cargo Load Tracks With Without Condition of Trailer Towed Powered Result Success Failure Powered Trailer 10 tons! X X X Athey Wagon 10 tons X X X Powered Trailer 10 tons X X Powered Trailer 10 tons X X X Athey Wagon 15 tons X X X Powered Trailer 15 ton j X X Powered Trailer 15 tons X X X X X Further sand tests on a 35$ olope demonstrated that when power is transmitted to the trailer of the experimental unit. this combination is vastly superior in slope climbing ability to the standard D-8 Tractor - Unpowered Athey Wagon combination (Figures 12 and 13). L - ÜSEWM DrriCIAL use OiiLY During hese trials, it became evident that It vas required to raise the bed of the experimental trailer in order to allow gieater track clearance (Figure ih) and that some modification of the povered universal Joint was required in order to allow increased articulation in the vertical plane (Figure 15)» Improvement in the tire track was also dictated in order to prevent side slippage of the tracks when turning or on aide hills (Figures l6 and 17). The moufication in track clearance and Joint articulation was a^conpllshed at the Laboratory Shops. The mud tests demonstrated that the experimental trailer could carry 15 tons of cargo on repeated passes over the soft ground adjacent to a slough. This was accomplished without transmitting power to the trailer. The experimental unit was able to i/limb out of the icua onto the hard bank when power was transmitted to the trailer. The Athey Wagon was unable to duplicate this maneuver (see Figures l8, iy and 20). ^he teats to date Indicate that a. The experimental trailer has a higher rolling resistance (caused by the necessity of turning over the drive chains and gearing) than the Athey Wagon and tbersfcre is somevhat Inferior to the Athey Wagon when utilized as a towed unit only. b. When power is transmitted to the experimec*3l trailer, its performance is vastly superior to fiat obtalneo without power and the experimental unit can markedly catperform the D-8 Athey Wagon combination insofar as the traversing of slopes and ground obstacles la concerned. It ia recommended that, after the snow tests are conducted thia winter at Fort Churchill with a re/ieed Galanot track that will prevent side slippage of the track on the dual wheels, consideration be given to continued development of the experimental trailer that will allow: a. Decreased rolling resistance when towed by declutching the trailer drlv«mechanisn from the wheels, and b. The ability to tr^ncmit power to the trailer at a much higher road speej clitn the present 25 feet per minute. u...*. ' f CIAL USE ONLY 10 APPENDIX B MEMORANDUM OF PROCEDURE AND REPORT OF TEST OF ARCTIC CARGO TRAILER AT FORT CHURCHILL, CANADA, WINTER , + 0: - -' - USE ONLY i] U. S. NAVAL CIVIL ENGINEERING RESEARCH AND EVALUATION LABORATORY CONSTRUCTION BATTALION CENTER Port Hueneme, California NTU.59/YD /EJB/pan 15 Deo 1953 MTMOKANDUM OF PROCEDURE, PROJECT NO. JOB ORDER SubJ: Arctic Cargo Trailer, Snov Teets of at Fort ChuiTchlll, Manitoba Canada, January and February I'^yh 1. GENERAL The Bureau of Yards and Docks initiaced the Project YD , Arctic Cargo Trailer, for the study and developnent of a cargo trailer that possessed the basic requirements for military operation in arctic areas for year round use. The present Arctic Cargo Trailer is believed to be the first effort to meet the requirements for operation in sand, snov, mud, ice an.: tundra. It was designed and constructed under the supervision of the Naval Civil Engineering Research and Evaluation Laboratory. Tests in mud and sand have been conducted at Port Hueneme, end the present instructions cover testing in snow and on ice. 2. PURPOSE These tests have for their purpose the testing of the prototype Arctic Cargo Trailer under arctic conditions in snov and on ice, to enable an analysis of its performance. 3. DESCRirTION The prototype trailer is 22 feet 6 Inches long by 9 feet 6 inches vide and 5 feet high. It has a 9 by 15 foot platform with a stake body. It weighs 6 tons and has a 15 ton maximum capacity, net. The unit is wheel mounted and features a two axle bogie drive with power obtained through a propeller shaft attached to the power take-off of the prime mover. Th particular take-off system is designed for use with a Caterpillar D-6 crawler tractor, and was manufactured by the Pettibone-Wood Manufacturing Company of Los Angeles, California Power may be supplied to the trailer either with or without powering the tractor. The propeller shaft la detachable, a 12 fnture permitting towing of the trailer behind military trucks and road tractors on surfaced rondo. Wheels may be used in single or dual tandem. A detachable articulated track, the Galanot tire track, is provided for use vith the dual tandem wheels. h. TEST OBJECTIVES The tests are designed to study the powered trailertractor performance when operating on snow and ice in the arctic to determine: a. Mobility of tractor-povered trailer combination. b. Tractive effort of tractor-powered trailer combination. c. Maneuverability of tractor-povered trailer combination. 5. TEST PROCEDURE a. Mobility Tests l) Select suitable snow-covered level site. 2} Prepare tractor-powered trailer combination. for operation with dual tandem wheels, vith proper tire deflection. (3) With power take-off disengaged, select a stalling load for the tractor. Note performance conditions. (U) With same load, speed and comparable (parallel) course, operate tractor with power to the trailer. When the trailer is powered, the tractor gears must always be placed in neutral, as the tractor receives its power through the take-off system, through a different gear ratio than is available through its own transmission. Compare performance. (5) Repeat {h) with power trailer powered but without power to tractor (forward position of tatceoff shift lever, neutral 00 tractor gears). 6) Repeat (3) to (S) using Galanot wheel tracks. 7) Repeat (3) to (5) ulth single tandem wheels. b. Maneuverability Tests (1) Select suitable level snow covered site. (2) Prepare wheels for 3^,000 pound gross load (wheel deflection adjustment if necessary). o. i.o.al USE ONLY 13 (3) With tractor povered, take-off disengaged: Operate equipment down stretch of level terrain at raaxiroum possible speed; raake normal turning, backing, and reverse turning operations; operate equipment on available slopes; when in reverse, backdrive of pover take-off shaft occurs and very low»peed must be maintained; operate equipment on roughest teir&in it will negotiate, noting performance on all operations. (I) Repeat (3) with take-off and tractor powered except for roversing. (3) Repcdt (3) and (U) with Galanot tracks attached. (6) Repeat (3) with b,0c0 pound gross load and single tandem wheels. c. Tractive Effort Teets (1) Prepare trailer with tandem wheels (duals), and 36,000 pound gross load. (2) Provide braking vehicle (D-8 Cateritllar crawler tractor or equivalent), with attacheu dynamometer. (3) With braking vehicle as load, and power transfer system disengaged, operate tractor In first gear. (U) Operate tractor at rated engine speed, recording maximum drawbar load, speed, and by measurement, slip. Operate at lesser loads, recording slip and speed, with constant engine speed. (5) Repeat (3) and (U) with tractor and trailer both powered. (6) Repeat (3) to (6) with wheel tracks applied. (7) Repeat (3) to (5) with single tandem wheels and 18,000 pound gross load. 6. EQUIPMENT AND MATERIAL a. Prime Mover, a Caterpillar D-8 Crawler Tractor with power take-off and spllned shaft, winterized. b. Prototype Arctic Cargo Trailer. * c. Dynamometer. d. Tapes, stopwatches, and revolution counter. e. Braking vehicle. f. Galanot wheel tracks for dual tandem wheels. g. Photographic equipment. h. Inclinometer, i. Trailer load (stake body has been equipped for loading with water to be frozen into ice by inserting plywood panels). C USE « OFFIC: lk * ji Tire inflating and pressure measuring equipment. StilJ and motion picture coverage of all tests shall be provided. Note: Items marked with an asterisk vere requested from ERDL. E. J. BECK Project Engineer APPROVED Director Construction Division Acting Head Equipment Research Dept.
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