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Archive for March, 2017

How Does An Airbag Work?

Airbags – they’re in every single new car coming out and if your car doesn’t have at least one airbag somewhere, it’s probably old enough to just about qualify as a classic.  It’s probably just about getting to the point that Millennials (or the children of Millennials – whatever trendy label you slap on that generation) will probably take airbags for granted much the same way that Gen X takes seatbelts for granted. (Boomers and Busters probably remember a time before seatbelts were compulsory back and front – I’m Gen X and I’ve got vague memories of cars with no rear seatbelts.  They weren’t common.)

The airbag concept has been around since the early 1950s, with patents being granted just about simultaneously in the US and in Germany to two different inventors, Walter Linderer and John Hetrick (which makes me suspect a little idea swapping was going on during the post-war Allied occupation of Berlin).  However, airbags didn’t really become popular until the 1970s, which was when Ford decided to give them a try.  This was about the time when legislating bodies around the world were taking a long, hard look at what was happening on the roads and were really getting serious about road safety, although it wasn’t until 1984 that the US made seatbelt use compulsory.  It was also in the 1980s that saw vehicles of all marques installing airbags in an attempt to pick up accreditation from the newly established EuroNCAP.

Now, of course, airbags are everywhere: front airbags for the driver, front airbags for the front passenger, side airbags, knee airbags, curtain airbags – even “pedestrian airbags” that deploy on the outside of the vehicle in some Volvos.

Most of the time, if we’re driving properly and everyone around us is driving properly, we won’t see diddly-squat of the airbags.  So it should be.  This means that how they work can be something of a mystery.

Any airbag, no matter where it’s located, has three parts to it: the bag itself, the sensor that tells the airbag to deploy (you don’t want the airbags firing at the wrong moment) and the inflation system.  The airbag itself is somewhat uninteresting: it’s a bag of nylon fabric that can pack up nice and tight, withstand the forces of sudden inflation, is airtight enough to actually inflate but has enough holes so it can deflate afterwards.  They also come lubricated with ordinary talcum powder to help them move easily and stay supple.  It’s the sensors and the inflation system that are a bit more fun.

The sensor picks up any force that’s equal or greater to the car going head-first into a brick wall at about 16 km/h, meaning that if you nudge the back of the garage at a crawl, if you ram the front bumper with a shopping trolley or if the cat jumps onto the car to enjoy the warmth of the bonnet, the airbag won’t deploy.  The sensors usually sit in the crumple zones and the typical modern vehicle will have about three of them.  The sensors are simple affairs, consisting of a ball in a tube as the main trigger.  If the ball is jolted out of the tube, this sets the inflation system off.

The inflation system is, quite literally, rocket science.  In other words, it uses the same technology as solid fuel rocket booster systems.  One of the early teething troubles they had with airbags was finding a method of inflating the bags that didn’t take up too much room or create an additional hazard (canisters of compressed gas had storage problems), deployed quickly enough and didn’t save your life but leave you deaf thanks to a thunderous explosion.  Nasty toxic gases were also to be avoided.  No point saving your life from the crash if it’s going to asphyxiate you as the gas dissipates.

The solution came in the form of two very reactive chemical compounds: sodium azide (NaN3) and potassium nitrate (KNO3).  Don’t play with these in the chemistry lab at school.  When the trigger goes off, these two are ignited so the reaction begins.  And does it begin or what!  These compounds burn fast and release a heck of a lot of nitrogen gas in a very short space of time.  This gas inflates the airbag super-fast so the bag deploys out of wherever it’s stored at over 300 km/h.  The nitrogen gas isn’t going to harm anyone as it goes back into the atmosphere – which is about 90% oxygen anyway.  Some mechanisms use slightly different chemicals but still work on the same basic principle and produce an equally harmless gas, such as argon.

In summary, the system works like this:

1 The force of a collision knocks the ball out of the tube (the most basic version of the accelerometer that detects a massive slowdown – there are other types out there).

2 The trigger flicks an electric switch that heats up an element.

3 The heat sets off a very, very fast chemical reaction.

4 The reaction produces heaps of gas very quickly, which fills the bag.

Can you get an airbag to deploy if you brake hard enough?  No.  In spite of urban legends and speculations tossed around by younger drivers, emergency braking in itself won’t set off the airbags.  Brakes just don’t generate the sharp, short force needed to set them off – even emergency braking is more gradual than that.  The airbags also won’t deploy if you are rear-ended (you’re being shoved forwards, not brought to a sudden stop) or if you use the bull bars on the front of a 4×4 as a DIY bulldozer (unless you try to get a running start into whatever you’re trying to push).  They will probably deploy if an enraged bull or ram takes a dislike to your car and charges it head-on, although I doubt this has been tested.  The popular amusing video of an elderly pedestrian setting off the airbag on the car belonging to an impatient driver is probably a fake, meaning it’s been carefully staged with a vehicle that has had the sensor system adjusted, then hit in exactly the right place.  But it’s still funny.

Airbags are not without hazards of their own.  Yes, they have saved thousands of lives.  However, anything that is moving at over 300 km/h is going to pack a lot of punch, even if it is only air and cloth.  Anyone who’s been on the receiving end of a well-flicked tea towel while drying dishes with siblings knows that “just” cloth can draw blood if it goes fast enough.  Not that an airbag will draw blood.  It can break your glasses as your head flies forward to meet it and it’s still going to hurt.  It will hurt even more and probably will draw blood and worse if you have anything on your lap that gets between you and the airbag – another reason not to try hiding your cellphone on your lap!

The force involved in a deploying airbag is too much for small children, which is why it’s best to put little kids of an age to sit in a booster seat in the back.  However, we know that sometimes, you just have to put a small person in the front (although this isn’t likely to happen unless you have three other littlies already in the back).  This is why some vehicles have occupant seat detection for the front passenger seat that has a weight sensor, so the airbag won’t go off if whatever’s in that seat is below a certain weight.

Airbags should never, ever, ever be used as a substitute for a seatbelt.  It’s a case of “both–and” rather than “either–or” and why would you want to skimp on your personal safety anyway?  It’s not as if an undeployed airbag is going to get in your way, limit your fun or restrict your freedom of movement or ability to drive well.  Don’t be a silly muggins – wear your seatbelt!

2017 Renault Megane GT & Renault Megane Zen: Private Fleet Car Review.

Renault‘s Australian renaissance continues to build momentum, with the all new Koleos and Megane range attracting plenty of positive comment. It’s fair to say that the GT and Zen Megane cars should be on your radar, and here’s why, as Private Fleet drives the Renault Megane GT and Renault Megane Zen.The Megane is a sweet looker, with a curvy overall shape and an extra bit of sheetmetal at the rear to emphasise the profile. Both have LED running lights in a hockey stick shape, LED rear lights and the GT takes that further with LEDs powering the main front lights. It’s compact outside, at 4359 mm in length and runs on a 2670 mm wheelbase, which offers 180 mm of rear seat knee room. Shoulder room for the 1814 mm wide (mirrors folded) pair is 1441 mm up front and 1390 mm in the rear. Front and rear track are almost identical at 1591 mm and 1586 mm. It’s a slightly bigger car, this fourth generation Megane, than the previous version, with the wheelbase 29 mm longer for an increase in overall length of 57 mm.Up front there’s a duet of petrol engines, with the Zen packing a mere 1200 cc four cylinder, with 97 kilowatts and 205 Nm. The turbocharged GT has 151 kilowatts at 6000 and a hefty 280 torques at 2400 rpm from a 1.6L powerplant. Both run on standard 95RON and power down via a seven speed dual clutch auto. From the fifty litre tank, Renault quotes a combined fuel consumption figure of 5.6L/100 km and 6.0L/100 km. Around town it’s just 6.8L/100 km or 7.8L/100 km.The GT is marked as 4Control, with subtle badging on the B pillars. This makes one wonder if it’s four wheel drive; no, it’s four wheel steering, with a rear wheel steering setup adding to the amazing agility of the five door hatch. It’s engineered so it’ll turn the rear wheels in the opposite direction to the front at either 80 kph or 60 kph, depending on which drive mode you’ve selected. Above those speeds the rears will turn in the same direction as the front. Does it work? Oh yes sir, it does. So do the brakes, in that unlike too many there’s real feedback, real bite, as soon as the pedal is touched. Distances between you and the car in front can be more finely judged with a variation of pressure, not relying on something to happen with a depression of an inch or so before action happens.

With the car riding on GT specific springs, dampers, and roll bars to the rest of the range, and combining with a super responsive steering system, lends the GT a sporting prowess that isn’t at odds with its seemingly cheapish $38K price. Turn in is crisp, sharp, and understeer is relegated to the file marked “No Longer Applicable”. This is thanks to a computer system that analyses steering angle and input 100 times per second. Not only is the GT a sharp handler, it rides better than the Zen. The lower spec car has 16 inch alloys, the GT rolls on 18s. Rubber is 205/55 for the Zen and 225/40 for the GT. The GT is sometimes jittery, but rides across imperfections better than the Zen, with the Zen more prone to bump steer and road intrusions, plus just that little more float from undulations. It’s by no means a bad handler in its own right, but backed against the wall by the brawnier GT, the differences are apparent.

Naturally the GT is better at getting underway, particularly with the dual clutch auto’s habit of thinking momentarily before engaging Drive from Reverse or from a standstill. Having said that, the Zen gets up and runs well enough for its engine size once the transmission has hooked it. There’s a faint buzz from the drivetrain as it does, the sound of the engine rising and falling along with the almost imperceptible changes, and suddenly you’re well and truly at highway speeds. Then the GT takes that and increases the grin factor with Launch Control…Rorty is a word used to describe a mechanical noise that emanates from the engine bay and also the exhaust. The GT has it in bucketloads. As good and as enjoyable as the Zen is in its driveability and handling, the GT amplifies that, enhances it, sharpens it, to the point that the smile you have becomes a grin of sheer enjoyment, visible from Mars. Turn in is precise, accelaration is electics, the aural sensation is sexy, the support of the blue trimmed bucket seats is amazing, and all come together to provide a drive experience for the senses. The Zen isn’t off in the aural caressment stakes, though, with enough of a growl to please most.When not fanging the cars around, you can enjoy the interiors. There’s proper soft touch materials on doors and dash, lacking, for example, in Jaguar’s much vaunted F-Pace. There’s adjustable screens for the dash and the centre touchscreen, satnav for the GT, a bigger 8.7 inch screen in the G as opposed to the Zen’s 7 incherT. Both have touch sensitive aircon controls; touchscreen for the GT and the same setup in the Zen as seen in the Koleos, with a strip built into the console. There’s heating for the seats in the GT which is unneccessary given their blue suede and cloth covering. Bluetooth? Natch.The Zen is simple black and charcoal cloth with contrasting white stitching, with a plastic trim on the doors not unlike the spotted pattern as seen on a whale shark. Both also have the quirk of placing audio on a separate stalk to the lower right of the steering column and cruise control in the centre console. The GT raises the stakes by having LED strip lighting and it’s at a level of intensity to not overwhelm the eyes during a night time drive. Both equal up in items such as Auto headlights, rain sensing wipers, 434 litre cargo which maxes at 1247L with seats down, push button Start/Stop and all four windows one touch up and down. Audiowise, both get great sound, with the GT a 12 speaker Bose system. There’s plenty of punch in the Zen’s 8 speakers though, with DAB available here as in the GT.Renault now offer a five year, unlimited kilometre, warranty, five years roadside assistance, and fixed price servicing for the first three services, providing the best of peace of mind.

At The End Of the Drive.
Renault are well poised in Australia to make a seriously positive impact on our crowded market. The Megane range has been spearheaded by a (soon to return to Australia) RS version however there’s more than enough in the 2017 range to appeal to drivers across the board. Up against tried and true entries from Korea, Japan, and European rivals, the Megane stands out as a worthwhile consideration. And starting at a sub $25K driveaway price, it enters this hotly contested market with plenty of value to back up a great driving experience. Go here Renault Megane for 2017 for the info you need to know.

Lamborghini Huracán Performante Breaks The 'Ring's Lap Record.

The Lamborghini Huracán Performante has already proved its extraordinary capabilities ahead of its unveiling at Geneva Motor Show next week. On 5 October 2016, the Huracán Performante set a new production car lap record of 6:52.01 min on the Nürburgring Nordschleife in Germany.

Following the day’s open sessions on the “Ring”, at 17.00 officials closed the track to other manufacturers. After official track checks this left just a
15-minute window for Lamborghini to make one attempt at the lap record with a production Huracán Performante, still in its development camouflage.

With Lamborghini test driver Marco Mapelli behind the wheel, who also drove the Aventador SV to its Nürburgring sub seven-minute lap time in 2015, the Huracán Performante warmed up its tires and made its rolling start, fitted inside and out with onboard cameras and telemetry to record the car’s lap. The Lamborghini team of R&D engineers, technicians and drivers, together with Stefano Domenicali, Chairman and Chief Executive Officer and Maurizio Reggiani, Board Member for Research & Development, watched the Performante disappear into the distance of the 20.6 km track.

In the sixth minute, the car was heard heading down the long straight with just three corners to go, and its audience counting down the seconds to watch the Huracán Performante pass over the line at 6:52.01 min.

“This was an incredible and emotional moment,” says Stefano Domenicali. “Together with Maurizio Reggiani we agreed during the car’s development that with the technical and performance prowess of the Huracán Performante, not only was a sub seven-minute lap at the Nordschleife possible, but the lap record too. We wanted to achieve the Nürburgring victory in advance of the Performante’s launch, which was a challenge in terms of weather and availability of the Nordschleife. Not only did we take the lap record, we took it by some seconds!

“To make this happen is something that every one of the R&D team who worked on this car can share in: it will forever be a defining moment in their careers,” concludes Stefano Domenicali. “I am so proud of everything achieved by Lamborghini people that day and extremely privileged to have witnessed it.”

The Huracán Performante features innovations in aerodynamics and lightweight engineering that, combined with its improved power plant, its four-wheel drive system, its Lamborghini Piattaforma Inerziale and a dedicated set-up, allows superior track performance to be maximized while delivering the most engaging and dynamic road drive.

Joining the Lamborghini development team at the Nürburgring were representatives from Pirelli, responsible for development of tires specifically for the Huracán Performante: the same Pirelli Trofeo R tires available on cars delivered to owners.

The Huracán Performante is revealed officially by Automobili Lamborghini at Geneva Motor Show on the first press day, 7 March 2017, 8.55 am at the Lamborghini stand. Follow the unveiling in Geneva at and join the conversation with #HuracanPerformante.

(Republished by Private Fleet on behalf of Lamborghini Australia’s PR compnay, The Origin Agency)