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).
50-hour, 4-run engine endurance test.
| Identifier | ExFiles\Box 43\1\ Scan071 | |
| Date | 25th September 1924 | |
| R.R. 493a (50H) (D.B. 175 25-9-24) J.H.D. EXPERIMENTAL REPORT. Expl. No. REF. Hs{Lord Ernest Hives - Chair}/TAG/LG2. 2. 25. a 50 hrs. test in 4 non-stop runs. 1st. day - 11 hrs. Duration - Tractor Propeller. A tractor propeller was used to absorb 324 B.HP. at 1800 r.p.m. equivalent to 9/10ths. throttle. Almost immediately the rocker boxes on A.{Mr Adams} and B. sides started flooding, and continued to do so throughout the test although the auxilliary oil pressure remained steady at 4.5 lbs.sq.in. after reducing it from 6 lbs.sq.in. After the test the engine was thoroughly examined for breakages etc. Outer exhaust valve spring broken - changed. 2nd. day - 16 hrs. Duration - Tractor Propeller. During this run two more valve springs were broken, (exhaust - outer), and one of A.{Mr Adams} side magnetos failed (Watford No. 74157) The tapered contact maker securing stud, broke at the threads. The broken parts have been handed to EY. for further investigation. 3rd. day - 16 hrs. 30 mins. Duration - Pusher propeller. Only A.1. and B.1. rocker boxes were flooding when the pusher propeller was used. A water leak developed at B.6. cylinder jacket at the welding around the inlet port on the top side. This was followed by B.3. cylinder jacket leaking at the welding of the patch under the exhaust port. Two more outer exhaust valve springs broke and two inner springs. In each case the springs broke at the second or third coil from the top. 4th. day - 6 hrs. 30 mins. Duration - Pusher Propeller. Last hour full throttle. During this run several more cylinder jackets contd:- | ||