Sulzer's RLA 90 series, which supplements the company's RND-M series, on which its design is largely based, should be useful for ships which can benefit from the increased efficiency of a larger propeller. The six-cylinder prototype RLA 90 is now being prepared at Winterthur for its trials in Apr. 1979; the first production engines may be delivered by the end of 1979. Main particulars of the new series include:-- Bore and Stroke--900 and 1,900 mm; Cylinder output (mer) --3,400 bhp at 90 rpm and 13.79 bars bmep (mean piston speed 5.7 m/sec.) or 3,600 bhp at 98 rpm and 13.42 bars bmep (mean piston speed 6.21 m/sec.); No. of cylinders--4 to 10, and 12; Output range--13,600 to 42,200 bhp; and Fuel consumption--146 g/bhp-hr, plus 3% allowance, at 100% load. Features of the RLA 90 include: availability of four- and five-cylinder engines; optional balancing gear (a Lanchester balancer) for engines with 4 to 6 cylinders; bedplate with integrated thrust-block; bore-cooled pistons, cylinder covers, and liners; an eight-bolt cylinder-cover; a modified crosshead; and Brown Boveri VTR turbochargers of increased efficiency and higher pressure ratio. The RLA is taller and heavier than the RND 90M, but its width is about the same and its length is somewhat less. The article includes details of its dimensions and weights for all numbers of cylinders, drawings showing its construction, and graphs in which it is compared with the RND 90M, RND 90, and RD 90 in respect of maximum cylinder pressures, cylinder-cover stresses, exhaust temperatures, and specific fuel consumptions. It is mentioned that the stroke/bore ratio, 2.11, is not much higher than that of some earlier and current Sulzer engines (the RND 76M and the RLA 56 have a 2.05 ratio). Order from BSRA as No. 49,957.

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  • Corporate Authors:

    IPC Industrial Press Limited

    Dorset House, Stamford Street
    London SE1 9LU,   England 
  • Publication Date: 1978-10

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Filing Info

  • Accession Number: 00194320
  • Record Type: Publication
  • Source Agency: British Ship Research Association
  • Files: TRIS
  • Created Date: Jun 13 1979 12:00AM