From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Article detailing the results of impact tests on wire, wood, and steel-plate wheels.
| Identifier | ExFiles\Box 4\4\ 04-page20 | |
| Date | 1st June 1912 | |
| THE AUTOCAR, June 1st, 1912. 983 Wheel Testing. The Results of Tests on Wire, Wood and Steel-plate Wheels. A QUESTION which has been exercising the minds of motorists for a considerable time, and which has given rise to several heated discussions, is that of the respective merits of the various methods of wheel construction. Wire, wood, and sheet metal all have their advocates, but the settlement of the discussion is not likely to occur until more data are available, although the data cannot be determined until the most comprehensive and searching tests have been carried out both on the road and in the laboratory. A start in this direction has been made by Messrs. Rudge-Whitworth, Ltd., the makers of the Rudge-Whitworth detachable wire wheels, who have for some time been carrying out impact tests suggested by Mr. Lester, M.Sc., as a means of comparing the ability of their wheels to withstand severe side shocks with the ability of wheels of different material and construction to withstand similar shocks. The method of carrying out these tests was described in detail in The Autocar of July 25th, 1908, so that here it is only necessary to say that heavy blows are administered to the wheel under test by means of a massive pendulum approximately 11ft. long, the “bob” of which weighs 480 lbs. This pendulum is allowed to swing over measured arcs against the rim of a wheel mounted on a dummy hub spindle, which in turn is part of a massive steel bar secured to a concrete monolith. The energy (in foot-pounds) imparted to the wheel by the pendulum is calculated from a simple formula. As this impact test is the only one which has been carried out up to the present of many, which, as we remarked previously, could be arranged to bring out the good or bad points of various wheel constructions, it is possible to form a judgment of the behaviour of various wheel constructions under road conditions similar to this test only. Now this test approximates, as far as laboratory conditions allow, to a side-slip terminating with a severe blow of one of the road wheels against a kerbstone. On the ability of the wheel to withstand the shock and its condition after in respect of temporary use and repairability, also the extent to which it has saved the axle from damage, the wheel must be judged. This last point may be made more clear by supposing an infinitely strong wheel to be undergoing this test. It is obvious that the severe blows will be imparted to the differential gear, driving bevels, spring clips, etc., so that it is necessary that a wheel should withstand shocks up to the point necessary to support the car but to give sufficiently to prevent the maximum energy of the shocks being imparted to the axle. The results of pendulum blows upon eight wheels of four different types are given below. Two of these wheels were of the ordinary artillery pattern made in America from the finest American hickory by a leading firm of American wheelwrights, and it must be said these wheels under these tests are far in advance of any other wood wheels which we have seen tested. The next pair were French hickory artillery wheels. TABLE: TOTAL PERMANENT DEFLECTION.* Row 1: American Wheel 1st Blow: in. .21 2nd Blow: in. .37, 1 spoke cracked 3rd Blow: in. .84, Rim moved 4th Blow: in. 1.41, Rim moved, 1 felloe split, 3 spokes broken 5th Blow: in. 2.20, Pulled smashed Weight: 47 lbs. Total Permanent Deflection Multiplied by Weight of Wheel (4th Blow): 66.27 Total Permanent Deflection Multiplied by Weight of Wheel (5th Blow): 103.4 Row 2: American Wheel 1st Blow: .28 2nd Blow: .46, 2 spokes cracked 3rd Blow: .67, †Flange cracked 4th Blow: .89, 4 spokes cracked 5th Blow: 1.17, 2 bolt heads cracked, rim held Weight: 46 lbs. Total Permanent Deflection Multiplied by Weight of Wheel (4th Blow): 41 Total Permanent Deflection Multiplied by Weight of Wheel (5th Blow): 54 Row 3: French Wheel 1st Blow: .25, 4 spokes cracked 2nd Blow: .41 3rd Blow: .64, 5 spokes cracked 4th Blow: 1.07, 2 spokes broken 5th Blow: 4.00, Smashed Weight: 39.3 lbs. Total Permanent Deflection Multiplied by Weight of Wheel (4th Blow): 42.26 Total Permanent Deflection Multiplied by Weight of Wheel (5th Blow): 181.7 Row 4: French Wheel 1st Blow: .27, 3 spokes split 2nd Blow: .43, 4 spokes broken 3rd Blow: .84, 1 spoke broken 4th Blow: 4.88, Smashed 5th Blow: - Weight: 38.25 lbs. Total Permanent Deflection Multiplied by Weight of Wheel (4th Blow): 188 Total Permanent Deflection Multiplied by Weight of Wheel (5th Blow): - Row 5: Steel plate Wheel 1st Blow: .53 2nd Blow: 1.00 3rd Blow: 1.6 4th Blow: 2.17 5th Blow: 2.79, Hub buckled† Weight: 37.75 lbs. Total Permanent Deflection Multiplied by Weight of Wheel (4th Blow): 81.9 Total Permanent Deflection Multiplied by Weight of Wheel (5th Blow): 105.4 Row 6: Steel plate Wheel 1st Blow: .59 2nd Blow: 1.00, Buckled at hub 3rd Blow: 1.6, No welding defects 4th Blow: 2.14 5th Blow: 2.8, Hub badly buckled Weight: 36.5 lbs. Total Permanent Deflection Multiplied by Weight of Wheel (4th Blow): 78.1 Total Permanent Deflection Multiplied by Weight of Wheel (5th Blow): 102.2 Row 7: Rudge wire Wheel 1st Blow: .31 2nd Blow: .55 3rd Blow: .82 4th Blow: 1.18, 3 spokes broken, 2 nipples pulled through 5th Blow: 2.56, 2 spokes broken, 1 nipple pulled through Weight: ~30 lbs. Total Permanent Deflection Multiplied by Weight of Wheel (4th Blow): 35.4 Total Permanent Deflection Multiplied by Weight of Wheel (5th Blow): 76.8 Row 8: Rudge wire Wheel 1st Blow: .36 2nd Blow: .60 3rd Blow: .90 4th Blow: 1.16 5th Blow: 1.49, No damage Weight: 29.2 lbs. Total Permanent Deflection Multiplied by Weight of Wheel (4th Blow): 33.8 Total Permanent Deflection Multiplied by Weight of Wheel (5th Blow): 43.5 Footnotes: * The effect of each blow is given below the total permanent deflection set up, so that the effect of each blow should be added to the preceding to get the total effect. † The cracking of the flange allowed considerable “give” to the spokes. Handwritten Note: x424 | ||