ENGINES OF Rl0l ARE OF HIGHEST MERIT.

Star (Christchurch), Issue 19060, 3 May 1930, Page 17 (Supplement)

ENGINES OF Rlol ARE OF HIGHEST MERIT.

The outstanding feature in the machinery of the airship RlOl is the circumstance that it is driven by heavvoil engines, the fuel for which can be procured readily at a low price and with a viscosity not too high for it to flow rapidly enough down to 0 deg. F. (according to “Engineering”). The engines .used are of the Beardmore Tornado eight-cylinder type. For aeronautical purposes the most notable feature of the design is that Messrs Beardmore have succeeded in reducing weight per horse-power to about 81bs. Wing-Commander Cave-Brown-Cave, who has taken an important part in the development of the power plant, has expressed the opinion that this figure can be reduced by half. As they stand, these engines consume less than 0.41 b of heavy oil per brake horse-power hour, but it is lii>rhly probable that they have been working

well below the optimum they may be expected to attain. It happens that the engine develops vibration when run at over 900 r.pm. and, accordingly the present results have been obtained with a continuous brake horse-power of 585, as against 700, for which the engines were designed. The matter is still under investigation, and it is reasonable to hope that improvements in the design of the engine will enable a higher efficiency to be obtained. As regards the advance which, in the meantime, has been made in applying heavy oil to an airship, it may perhaps be worth while to point out that, on the figures given and assumed above, the total weight of the engines with the heavy oil fuel for a 50-hour flight, for which the engines were designed, would be less than the weight of the fuel alone consumed by petrol engines. The cars in which the power units are carried are so arranged that, when a thorough overhaul is required, a complete car, including its airscrew, etc., can be removed and replaced by a spare one while the ship 1S

at the mast, so as to allow the chartga to be made in the * shortest possible time, and to permit a fresh type of car to be developed for any improved typo of engine without delaying or altering the ship. The arrangements within th« car, however, allow the whole of the machinery to be accessible to the engineer for carrying out any repairs which have to be made during flight. The maximum diameter of the car is less than half the diameter of the airscrew, thus minimising its addition, to the drag of the ship. The engineer can, nevertheless, pass along the full length of both sides of the engine, and reach, any pipe or joint under it, while remaining entirely protected from the passing air and from much of the airscrew noise. Through two hatches on the port side, which he can open, he has free access to the whole or the top and also to the starboard side of the engine. while remaining well protected lrom the passing air stream. When necessary, it is possible to remove a c/hnder head, piston and connectingrod while the ship'is in fHyhr