M.I.R.A. Does Good Work: Proving Ground Developed
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IN addition to the Belgian pave at the Motor Industry Research Association's Nuneaton proving ground, other sections have been developed recently for suspension and noise tests. These include a half-mile corrugated section, which has been installed to reproduce the effects of the " wash-board " surface found on many unmetalled roads overseas, and a cross-country track with a water splash 3 ins. deep. There is also a 200-ft.long dust tunnel for use in studying dust entry into vehicles.
To accentuate road noise, a quartermile stretch of road has been laid comprising 200 yds. of sawetooth surface and a similar length of uneven ground consisting of regularly spaced lumps of 3-in, diameter and 3-in. pitch. A smooth road, with a carpet of fine asphalt top dressing, has been laid as a comparative reference for the noise tests.
Investigations to determine the effects of leaded fuel on valves are being continued in the M.1.R.A. laboratories at Brentford, the results so far indicating that glittering of the valves and seat burning can be reduced by using spedfic materials. In comparative tests, one valve failed in.20 hours, but with Stellite and Brightray facings, the failures occurred at 80 and 60 hours, respectively. The valves giving the longest life in these tests were made of XCR.
Experiments with ValVes
Under different conditions, a Sillchrome I valve failed in 40 hrs., and a Brightray-faced Silichrome 1 valve in 54 hrs. Stellite-faced Silichrome 1, XP and XCR valves were in good condition after 100 hours' running under similar conditions. Further investigation is being made to measure the effect of valve rotation in inhibiting these failures and of cycling tests in place of the present full-power trials.
Experiments made at the Cambridge University Engineering Laboratory have shown the L-sbaped pressure-backed piston rings, which were developed to combat excessive blow-by at high speeds, can have an appreciable effect in reducing friction. Measurements of friction losses by motoring tests have shown an improvement of 8-10 per cent. of power in comparison with normal rings. Ventilation of public-service vehicles has also been surveyed by M.I.R.A., and results indicate that a heat exchanger can be used to replace the normal radiator andlan. This, together with simple ducting and cool-air intakes, provides improved passenger comfort during all seasons of the year in doubledeck buses operating under conditions similar to those in Southampton. Other advantages include greater cleanliness of the interior of the bus, prevention of moisture condensation on the windows, and elimination of dust on the rear platform.
A machine has been constructed for measuring braking characteristics to determine methods of combating fade. The apparatus records the speed of the brake drum, force on the facing, friction force and temperatures of the drum and facings. This apparatus is also capable of acting as art inertia machine and performing run-down tests under conditions similar to those of a decelerating vehicle. Tests are at present in progress.
The Association's annual report, which has just been published, states that the number of members is now 915.
EXPORT OPPORTUNITIES QEVENTEEN normal lorries and one k.) tipper are required by the Makhzen Transport Service, Spanish Morocco. Tenders should be submitted by December 21. Further information can be obtained from the Board of Trade, Millbank, London, S.W.I.
The director of the I.ake Scutari land reclamation scheme requires catalogues of British bulldozers and dumpers. These should be sent to ILK ConsulGeneral, 12, Bice, Zagreb, Yugoslavia, for forwarding DUNNAGE MEMORIAL LIBRARY
AMEMORIAL to the late Mr'. James Dunnage, F.Inst.T.A., is to be made in the form of a library. Contributions are invited by the secretary, Institute of Traffic Administration, Dudley House, Southampton Street, London, W.C.2,.