When wheels turn faster

On op­po­site sides of the world, hu­man­ity’s most im­por­tant in­ven­tion has been made bet­ter

The Witness - Wheels - - MOTORING - AL­WYN VILJOEN

HU­MAN­ITY’S most im­por­tant tool has in re­cent times been made a lit­tle bit bet­ter on op­po­site sides of the world.

In Ja­pan, two broth­ers made a bi­cy­cle axle so smooth it can add at least three kilo­me­tres per hour to a rider’s speed.

In Eng­land, a group is build­ing wheels for the su­per­sonic Blood­hound record car, while wor­ry­ing about the weight of a bag of sugar.

Ja­panese over-en­gi­neer­ing

From Ja­pan, Ja­son Clenfield re­ports for Bloomberg Busi­ness­week about a set of bi­cy­cle wheels that costs over R94 920 a pair.

The wheels turn on su­per-smooth axles, en­gi­neered by broth­ers Nobuo and Yu­taka Kondo at Kondo Ma­chine, a com­pany that em­ploys 30 en­gi­neers who make parts for Rolls-Royce jet en­gines and ma­chines that make parts for Toy­ota cars.

They call ther wheel the Gok­iso wheel and their tests prove it turns four times smoother than com­pet­ing wheels. Spin a Gok­iso wheels at 28 km/ h on a test track and it will take six min­utes to come to rest, com­pared with about 90 sec­onds for a high-end, re­sis­tance-im­paired com­peti­tor.

The Kon­dos told Clenfield they weren’t think­ing much about sales when they started de­vel­op­ing their bike wheels in 2009.

Younger brother Yu­taka had just lost to his older brother in an en­durance race and like all lit­tle broth­ers, he blamed the bike. But he was right, as the rear axle had been partly crushed dur­ing the four-hour ride. Yatuka took about six months to de­velop an axle that could re­main com­pletely straight, sus­pend­ing it in­side a protective sleeve that re­dis­tributes weight and ab­sorbs shock.

They have since tested the axle at speeds of up to 300 km/h and have run it twice around the Earth at 100 km/h, (a test that took 10 hours a day for 100 days). Af­ter all that, Nobuo says, the wheels still spun like new.

The Gok­iso has one-third less me­chan­i­cal re­sis­tance than the next-smoothest wheel on the mar­ket, the broth­ers say, which means speeds of three kilo­me­tres per hour more for most rid­ers and cru­cial sec­onds shaved off pro­fes­sional’s race times.

Even in Ja­pan, pay­ing close to R95 000 for a set of bi­cy­cle wheels is a lot, which is why only 30 sets of the tyres have sold in four years, and about 1 000 of the cheaper mod­els that go for “only” R39 650 a pair.

English rev­o­lu­tions

In Eng­land, en­gi­neers at the com­pany Blood­hound SCC are pre­par­ing a su­per­sonic race car that will at­tempt to set a new land speed record at Hakskeen­pan near the Namibia bor­der.

Pow­ered by a F1 rac­ing en­gine and the jet en­gine from a Ty­phoon fighter, the Blood­hound can, in the­ory, blast across the pan quite a bit faster than the speed of sound. To han­dle such su­per­sonic speeds re­quires wheels that can with­stand stress and can turn with­out de­form­ing from 10 200 rpm.

Th­ese rev­o­lu­tions are only the lower limit, be­cause it is not cer­tain how fast the Blood­hound will go and hence how fast the wheels will ac­tu­ally be turn­ing at top speed. When go­ing flat out, the wheels gen­er­ate 50 000 ra­dial g at the rim, which means that a one-kilo­gram bag of sugar set on the rim would weigh 50 tons or as much as a truck.

To han­dle that sort of stress, the wheel discs are made of a spe­cial alu­minium al­loy cre­ated for cut­ting-edge aerospace ap­pli­ca­tions called 7037, which is forged into a per­fectly bal­anced “cheese” us­ing hot and cold presses.

The com­pany forg­ing the wheels, Blood­hound SSC, said the aim of both presses is to re­move any voids and form a stronger, more com­pact ma­trix in the crys­talline struc­ture of the alu­minium.

Even such strength­en­ing, fol­lowed by pre­ci­sion ma­chin­ing by the Cas­tle com­pany and testing by Rolls Royce has its lim­its. Should the crew that has been sweep­ing the pan over­look a sin­gle stone, the re­sults could be cat­a­strophic.

A pebble hit­ting the wheel at su­per­sonic speeds could cause it to lose its bal­ance, which would quickly dam­age bear­ings and in­crease the wob­ble un­til the wheel tore it­self apart in a man­ner nor­mally only seen in an ex­plod­ing jet tur­bine. An­other dan­ger is that the front wheel could fire a stone at the rear wheel or into the body of the car at su­per­sonic speeds.

This could be ex­tremely danger­ous for the driver, Andy Green, de­spite the car­bon com­pos­ite cock­pit. To pro­tect against this, Mor­gan Ad­vanced Ma­te­ri­als is de­vel­op­ing light­weight com­pos­ite bal­lis­tic pan­els to guard the cock­pit and other vi­tal ar­eas. The lam­i­nated pan­els will not stop the stone, but will tear to dis­si­pate its su­per­sonic mo­men­tum. • al­wyn.viljoen@wit­ness.co.za

PHOTO: TAKUROH TOYAMA FOR BLOOMBERG BUSI­NESS­WEEK

Nobuo Kondo (left) and Yu­taka Kondo made a bi­cyle axle so smooth it can add at least three kilo­me­tres per hour to a rider’s speed.

PHOTO: BLOOD­HOUND SSC

Blood­hound SSC staff with one of the wheels that is de­signed to han­dle su­per­sonic stresses over Hakskeen­pan near the Namibia bor­der.

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