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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).
Crankcase after a crack test, detailing nine cracks found and recommending repair.

Identifier  ExFiles\Box 132\3\  scan0063
Date  24th December 1936
  
- C. to Rm.{William Robotham - Chief Engineer}
Lodge jw T
216.
24.12.36.

B.17 UNIT.

Report on Crankcase after Crack Test.

Crankcase No. EB.1697 modified to Ex.18253 (top half).
Fitted 13.9.36.

Has done 119 hours of test-bed running, 20 hours of which were at 1/2 load 4,000 - 4500 R.P.M., 40 hours of which were at full load 4,000 - 4,500 R.P.M. Has run 22,000 miles on road in chassis B.23 AE.

On examination after chalk-crack test, the above crank-case was found to be cracked in 9 places, though the cracks are small, the worst being at the radius adjacent to No.4 bearing-housing on the offside (See drawing Ex.I.103).

The bearings affected are No.1, on the near side;* No.4 both sides and No.7 both sides.

Cracks are apparent in the bores of No.4 and No.6 cylinders as indicated in Ex.I.103.

A crack has also occurred near one of the holes adjacent to the second front engine support on the near-side flange and extends from the edge for approximately .100" (Ex.I.103)

Attention is drawn to the fact that all these cracks bear a marked similarity in positions and characteristics to those found in crankcase Ex.19357 ex B.3 unit, a report on which was issued 4.12.36. (RHC{R. H. Coverley - Production Engineer}/HPS.{Horace Percy Smith - Experimental Factory Mgr}1/EP{G. Eric Platford - Chief Quality Engineer},3.12.36.)

This crankcase is not badly distorted however, and is to be built up and used again.

*Not shown on Ex.I.103. The crack is in the same position as that on the near side of No.4 bearing housing, but is slightly smaller.

Herewith Ex.I.103.

R.{Sir Henry Royce} Hollingworth.
  
  


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