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).
Tests to determine the tension in holding down studs for 'Kestrel' cylinders.
| Identifier | ExFiles\Box 179\3\ img170 | |
| Date | 6th April 1932 | |
| ORIGINAL To R.{Sir Henry Royce} From Hs{Lord Ernest Hives - Chair}/Lov.{Mr Lovesey} c. to Re. Wor.{Arthur Wormald - General Works Manager} c. to Re. K.{Mr Kilner} c. to By.{R.W. Bailey - Chief Engineer} EF. Sft.{Mr Swift} c. to Mr. Jaques. c. to Mr. Smithdale. "KESTREL" CYLINDERS. TENSION IN HOLDING DOWN STUDS. It has been proved that the reliability of the "Kestrel" cylinder top joint depends upon not falling below a certain degree of tightness of the holding down nuts. At present this is insured by employing a spanner with a slipping torque of 85 lbs.ft. We have now made some tests to determine the resulting tension in the cylinder studs with the nuts tightened to a torque of 85 lbs.ft. A Bucton Tensile machine was used and arranged to read the tension in a stud as the nut was tightened up on its correct bridge piece. The pieces tested and results obtained are as follows:- (1) Std. intermediate studs E.30771 with bridge pieces E.30767 and nuts E.30769/1. These have conical seated nuts of 16 T.P.I. Tightening torque 85 lbs.ft. Resulting tension in stud (Avge) 3.94 tons. Efficiency of nut under these conditions 8.6%. (2) Large diam. fine thread studs E.38709 with bridge pieces E.4401. and nuts E.38708. These have larger diam. flat seats and the nuts have 20 T.P.I. Tightening torque 85 lbs.ft. Resulting tension in stud (Avge) 3.56 tons. Efficiency of nut under these conditions 6.23%. (3) Std. end studs and cap nuts which tighten down on the flat Alum. face of the cylinder block. These end studs are also used when the intermediate studs are of the larger diam. as on K.39 Type Test. Tightening torque 85 lbs.ft. Resulting tension in stud 4.09 tons. Efficiency of nut under these conditions 8.93 %. These results show that for the same tightening torque there is less tension in the large diam. fine thread studs - as used on K.39 Evaporatively Cooled Type Test - than in the Std. studs as used on previous type tests. Handwritten notes: x2965. x3866. | ||