From the Drawing 13021
Page 44
Page 45
If you've noticed an error in this article please click here to report it so we can fix it.
by Graham Montgomerie The first outsider to watch a VW IT impact test, Graham Montgomerie investigates the safety research which is necessary before a new vehicle can be sold to the public.
EFORMABLE STRUCTURES jilt into a vehicle are rather like .e engines and ambulances. Du hope you'll never need em, but it's comforting to low they are there.
It is .a regrettable fact of life at we cannot expect to avoid rad accidents entirely. 'though vehicle and cornDnent manufacturers continue improve brakes, handling and eering it would be naive to isume that eventually, the icident would be eliminated. Thus all vehicle manufacrers must put a great deal of ought into their cab design to ve the driver and passengers e maximum chance of survival an impact. I visited the Volksagen research and developent departments at Wolfsburg see how a major light vehicle anufacturer goes about satising the various moral and legal quirernents. of safety in an :cident. I was privileged in ed watch an LT being ashed to prove how well its )formable structure worked. According to Volkswagen's )mmercial vehicle "crash
■ ecialist— Hartmut Burger, I as the first person outside the N personnel to witness an LT ipact test.
It was an interesting ex!hence.
Omph impact speed The unladen LT which eighed 1700kg (34cwt) was .ojected into an old American ir at an impact speed of Bkrn / h (30mph). Old US-built lrs are frequently used by DIkswagen as they are big and .avy. This particular example eighed 1800kg (36cwt).
The impact was contained by e deformable zone in the front the LT with surprisingly little trusion into the footwell area the inside. One point which ipressed •me particularly was le way in which the doors ayeci closed throughout the ash, but could be opened and osed using the door handle tervvards.
The US safety and impact sts were the first requirements r Volkswagen as this is an lportant market for the corn pally. A lot was learned from the initial crash programme with the Type 2 leading to the incorporation of the front deformation zone, deformable brackets and the safety steering system. More metal was also included where the driver's and passenger's legs went. Much of the Type 2 development in this area was put to good use in the LT range where the problems if anything were more severe due to the extra weight of the LT range.
It is worth mentioning at this point that a manufacturer like VW has to test an example of each model before acceptance in America. Thus it is not sufficient to test merely one LT variant; the company has to crash test each individual model, ie LT 28, 31, 35 and so on.
An expensive business. The VW research area is in fact littered with smashed vehicles of all shapes and sizes and makes.
Bright dummies
Dummies play an important part in Volkswagen commercial vehicle safety development — and I am not being rude about the ability of the engineers.
These dummies have been de veloped by consulting experts in the science of biomechanics to be equipped with elaborate and expensive) measuring instruments which can record, for example, loads on the skull and deformation of the rib cage during the simulated accident.
I mentioned that these test dummies are expensive — £4,000 to £5,000 dependent on what is to be measured.
This cost can then be doubled when the instrumentation is added and the spare parts requirement is included.
The most expensive member of the Volkswagen family of dummies goes by the splendid name of Oscar Humanus. With Oscar the strength of each sec tion of his body has been matched as closely as possible to that of the human body. This means that his ceramic leg bones, for example, will fracture under the same load that would break a human bone. Oscar has one tremendous advantage, however, over a mere human — his bones are easily replaceable.
Oscar's instrumentation is also capable of recording impact and the resultant -injuryto the softer parts of the body.
As I mentioned, Oscar is the most expensive member of the VW family at around £15,000. Indeed the total family of dummies maintained by Volkswagen — 50 males, two females and three children — represents total investment in the region c £250,000.
One specific area which WE developed as a result of th crash testing was the steerinc column support.
The steering layout in the ca is so designed that if the driver body strikes the steering whei this tilts away. The metal suj porting strut assembly is als designedto fold at a predete mined impact loading so tl-N the entire steering column ca swing forwards in a relativel gradual manner when struck b the driver's weight.
Fast film
The improvements in photo graphic techniques have beer a great help to VW in thei assessment of what happen: during an accident. Using file speeds of one thousand frame: per second, the entire crash tes is filmed both from outside thc vehicle and also from within When the film is slowed righ down it is possible to see thc deformation occurring an which area deflects first. Fol lowing the movement of thc dummies during a test acciden is also a lot easier with /hi: method.
Most of the photographic techniques were developed ir the USA, according to Volks wagen. This applies particularl) to the cameras installed in thE vehicle itself, These are capablE of withstanding 30g withou. damage.
Set-back engine There is quite a difference between front and rear-enginec vehicles in terms of their poten• tial ability to resist an impact. With a rear-engined machine like the air-cooled Type 2 there is plenty of space at the front for a deformable structure. Obviously, this does not appl), so easily to the front-engined LI which is the reason for the en• gine being set so far back in thie type of chassis.
As well as preserving the occupants in a crash, some form of protection is also required b■,, the fuel tank. The Americans once again were first on the scene with a fuel leakage maxi. mum. Volkswagen carried out E number of crash tests with thE early vehicles, noted where the fuel leakage occurred anc modified the system. Existinc legislation permits a maximum fuel leakage after an impact 01 24gm per minute (about three quarters of an ounce).