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).
Spring rebound dynamics and the design of a fan, belt, and water pump test rig.
| Identifier | ExFiles\Box 159\6\ scan0084 | |
| Date | 25th August 1940 | |
| R m/GB.1/ET.25.8.40 -2- 3. The angularity effects of the conn. rod will make the time on which the spring is on rebound greater than the time on which it is on bump. This will have the effect of increasing the average load (max.+ min. / 2) on the spring, and it is hoped that this will cancel the effect described in 2. above and make the test of the same severity as the normal procedure. Regarding dynamic rate and friction tests it is proposed to have two diagram scales i.e. 200 lb/inch and 100 lb/inch, the former for heavy springs and the latter for lighter springs. Would you say those were about right? FAN, BELT AND WATER PUMP TEST RIG. - The purpose of this rig is duration tests on fans, belts and water pumps. According to drawings which we have the Buick fan belt endurance test is 300 hours at 4000 crank r.p.m. The fan dissipation is 11 H.P. It is assumed that the test is carried out in still air and behind a radiator. We are interested in the horse power dissipated by the fan when there is a stream of air flowing on to the front of the radiator (as in normal driving). It is proposed to mount an electric motor driving the fan, on trunnions and measure the power required to drive the fan with various air velocities in front of the radiator. To get the various air velocities in front of the radiator a small wind tunnel will be made using an existing blower powered by an 8 H.P. motor. The blower has an exit about a foot square. The measured wind speed at the exit is 90 m.p.h. A tunnel 2 feet square is required. Coupling the blower to the tunnel directly will only give a velocity of 22 1/2 m.p.h. The K.E. of the wind coming from the blower is sufficient to give an air speed of 57 m.p.h. It is hoped by the arrangement shown in the sketch to get a tunnel wind speed of somewhere near 50 m.p.h. For cooling tests on radiators these will be set up in the tunnel and the fan will be used to assist the blower to get the higher air velocities. Would like a copy of the 73 page booklet of tables etc., mentioned on page 508 in the S.A.E. paper on Radiator Development and Car Cooling in the S.A.E. Journal dated December 1936. | ||