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).
The results of 'Spectre' frame distortion tests, identifying a weak welded joint.
| Identifier | ExFiles\Box 94\4\ scan0024 | |
| Date | 1st January 1935 | |
| GRN x327 To Sg.{Arthur F. Sidgreaves - MD} and Wer. from E.{Mr Elliott - Chief Engineer} E.7/HP.1.1.35. c. Hs.{Lord Ernest Hives - Chair} By.{R.W. Bailey - Chief Engineer} RHC.{R. H. Coverley - Production Engineer} Da.{Bernard Day - Chassis Design} SpectreCodename for Phantom III Frame Distortion Tests. Referring to the result of the above as given in RHC.{R. H. Coverley - Production Engineer}2/MS.20.12.34, this test has shown us that the weakest feature of the frame in respect to resisting braking torque on the front axle is the welded joint where it has split open and allowed the side members of the frame to distort. There is no doubt that had this joint stood up the frame would have carried more load than it eventually did. We have since found that owing to a mistake on the part of the suppliers a certain portion of the seam on each side member was not welded locally to the failure, and this no doubt contributed in some measure to the result. When originally considering this welded construction we had test pieces made of the full frame section which we twisted torsionally and demonstrated that the welded joint was as strong as the frame itself when loaded in this manner. We did not however make any test pieces for bending moment, and we are now proceeding to do this, using a closer pitched welding so that we can satisfy ourselves as to the strength of the joint for resisting bending. We have learned a lot from this destruction test of the frame and front suspension, but we do not think this result should stop us from building experimental SpectreCodename for Phantom IIIs to the design as it is essential that we should have chassis running about, and we do not anticipate any very great departures from the present construction although at the same time we shall ensure that the front of the chassis will be made stiff enough for all purposes. We do not regard the test made as being truly representative of road conditions and we think it is rather harder on independent front springing than on the existing production types. | ||