Figure 1.Image taken from the net.<\/p>\n Introduction<\/strong><\/p>\n Lotus cars sold<\/p>\n They were bought for their:-<\/p>\n All the above were integrated within a total framework design.<\/p>\n The above list is heavily dependent on a select group of components [either bought in proprietary or in house manufacture] that delivered the desired outcomes and met strict criteria.<\/p>\n Many of these components often contributed significantly to the overall aesthetic, many are extremely functional and beautiful in their own right. They formed part of a complementary whole.<\/p>\n In this series we examine:-<\/p>\n Understanding Lotus\u2019s use of proprietary parts provides invaluable learning opportunities not just historical but right up to the present day. These lessons are not just applicable to automotive engineers\/ designers but to the wider Industrial \/Product Design professions.<\/p>\n The Skillful and creative adoption, absorption and integration of components was a powerful factor in the Chapman design methodology and contributed significantly to both competition and commercial success. It also feed his ability to mutate parts and materials to his desired ends.<\/p>\n The use of components is a fundamental skill of the Industrial Designer and the direct provision of added value.<\/p>\n Subscribers might like to see related A&R series:<\/p>\n Advantages of Independent Suspension<\/strong><\/p>\n Singh Reyat summarizes the advantages as follows:-<\/p>\n Sprung and Unsprung weight <\/strong><\/p>\n Summarized by R.Singh as:-<\/p>\n \u201cThe unsprung weight should be kept as low as possible as the reduced unsprung weight results in obtaining a better ride \u201c<\/p>\n On the subject of Independent Suspension systems he comments:-<\/p>\n \u201cIn independent suspension, there is no axle beam running below the frame like the conventional suspension system, suspension for each wheel is an independent unit and is free from the effects of one another, the linkages used in the construction of this suspension compromise the basic features of the suspension.<\/p>\n The following types of independent suspension system are applicable to automobiles:-<\/p>\n De Dion Tube<\/strong><\/p>\n Independent Rear Suspension<\/strong><\/p>\n Figure 2.Editors sketch of early de Dion car fitted with their own rear suspension arrangement.<\/p>\n Abbey:-<\/p>\n \u201cAlthough independent rear suspension are not widely used, the different systems in use may be briefly reviewed:<\/p>\n The conventional \u201clife \u201caxle that this an axle casing containing the final drive gears , differential and axle shafts \u2013is a relatively heavy unsprung unit .attached to leaf springs , torsion bars or coil springs , it has a tendency to bounce on poor road surfaces ,adversely affecting road holding and stability. Moreover, the engine torque reaction tends to lift the right hand wheel [viewed from the rear] off the ground, causing wheel spin on slippery surfaces<\/p>\n The de Dion type rear suspension greatly reduces the unsprung weight by mounting the differential casing on the chassis frame and driving the wheels through two short , universally jointed shafts .the rear wheel hubs ,however are carried on an axle beam to which the suspension members are attached.it is a common fallacy to mistake de Dion suspension for true independent rear suspension ,it will be obvious ,however that this is not the case since the wheels are linked by the axle beam<\/p>\n From the net:-<\/p>\n \u201cDe Dion suspension uses universal joints<\/a> at both the wheel hubs and differential<\/a>, and uses a solid tubular beam to hold the opposite wheels in parallel. Unlike an anti-roll bar<\/a>, a de Dion tube is not directly connected to the chassis<\/a> nor is it intended to flex. In suspension geometry it is close to the trailing beam suspension<\/a> seen on many front wheel drive<\/a> cars, but without the torsional flexibility of that suspension.<\/p>\n Contents<\/strong><\/p>\n History <\/strong><\/p>\n The de Dion tube was named after Comte Jules-Albert de Dion<\/a>, founder of French<\/a> automobile manufacturer<\/a> De Dion-Bouton<\/a>. The tube, however, was invented around 1894 by co-founder Charles Tr\u00e9pardoux<\/a> for use on the company’s steam tricycles.[3]<\/sup><\/a><\/p>\n Advantages and disadvantages<\/strong><\/p>\n Advantages:<\/p>\n Disadvantages:<\/p>\n De Dion: Lotus application<\/strong><\/p>\n Using the Lotus book as reference we note the main models to use de Dion rear suspension as:-<\/p>\n In the Lotus Story \u2013Part 4 Colin Chapman stated:-<\/p>\n \u201cDe Dion type rear suspension was fitted with inboard brake drums and the suspension medium was transverse coil springs .this form of rear suspension was chosen mainly to keep down wheel spin and to reduce unsprung weight, a \u201clive\u201d axle tends to lift under wide throttle openings, as torque reactions tends to lift one rear wheel to induce wheel-spin. This is obviated with the de Dion type axle due to the \u201cdiff\u201d housing being bolted up solidly to the frame, the drive was taken out to the rear wheels by two separate, short drive shafts\u201d<\/p>\n Whilst Smith adds:-<\/p>\n At the rear a de Dion type of axle was used ,in conjunction with a transverse helical spring held in tension ,an damped b Armstrong piston \u2013type units .the brakes were fitted inboard ,each side of the differential housing \u2026\u2026\u2026.\u201d<\/p>\n \u201cLotus Mk.IX Competition Car, Autocar, 1955 quotes:<\/p>\n \u201cthe rear wheels are supported by a de Dion tube and are therefore, not fully independent .the axle tube is swept behind the final drive unit and is made from 3 inch diameter 16 swg mild steel tube .each end of the tube merges into a fabricated housing provided with two opposed conical seatings .into this fits an aluminium casting containing the hub and race assembly \u2026\u2026\u2026..which makes an ingenious and extremely light unit \u2026\u2026\u2026\u2026..\u201d<\/p>\n Figure 3.Editors sketch drawing of de Dion of rear suspension in Lotus Eleven<\/p>\n Further details of the Eleven set up are provided by Smith:-<\/p>\n \u201cAt the rear a de Dion layout was used which saved 10 valuable unsprung pounds from the layout used in the Mk.IX. The tube was pierced to allow the half shafts to pass through , so giving them much greater length and less deflection for the universal joints .the short tubular shafts were still extensions from the Rudge \u2013type hubs , but now carried on pair of taper roller races in a light alloy housing .as earlier a pair of radius arms located the axle on each side , but now one of them was triangulated into an A-frame to absorb lateral forces .ultralight hydraulically operated 9.5 inch Girling discs were fitted out board at the front and inboard at the rear , the calipers of the rear being carried ahead of the axle to reduce overhand loads \u2026\u2026\u2026.a horizontally mounted hand brake operated the rear calipers through inner and outer cables\u2026\u2026.\u201d<\/p>\n \u201cAutocourse\u201d1956:-<\/p>\n \u201cthe de Dion rear suspension of the Le mans car has been completely redesigned and the tube diameter increased to 3.25 inches .he outboard universal joint is now inside the tube instead of being located in the conventional manner .the new arrangement has meant a valuable saving here of 15 lbs. ,unsprung weight .the rear wheels are located longitudinally by parallel trailing arms , whilst a diagonal bracket has been introduced on the off-side which provides the equivalent of a Panhard rod of 64 inches in length\u2026\u2026..\u201d<\/p>\n Learning Opportunities<\/strong><\/p>\n Our learning \/educational opportunities are intended to be challenging thought provoking and requiring additional research and\/or analysis.<\/p>\n These opportunities are particularly designed for a museum\/education centre location where visitors would be able to enjoy access to all the structured resources available in conjunction with any concurrent exhibition.<\/p>\n In this instance we suggest the following might be appropriate:-<\/p>\n Understanding the potential of componentry particularly proprietary items provides some of the following learning:-<\/p>\n![\"74203\"](\"http:\/\/colinchapmanmuseum.org.uk\/wp-content\/uploads\/2017\/12\/74203.jpeg\")
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