Can Technicians really Sell?

Can a great technican make a great salesman?  There are many philosophies behind putting a technician on the sales floor but of course one needs to be ultra careful of where the new sales peron’s loyalty lies. I for one know that most technical people in the computer field are hard core Apple fanatics. Would they find it easy to push an unknown make of tablet to the unsuspecting customer? Technical people in the printer industry love HP – how do they promote Epson or Lexmark when they may have had poor support through the supplier spares chain?

The Dilbert Principle (known as the Peter Principle)
Credit: The Dilbert Principle (1995)

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Measuring Power, HP myths and Energy Dissipation

There is such a lot of reading material on power and energy that I was surprised to receive a mail from a reader as to why he finds it all rather unglamorous – too many factors are taken into consideration and as far as he was concerned their should be a universal standard i.e. kilowatts or horsepower,  not both – also intriguingly enough why we cannot just turn calories into joules into horsepower or kilowatt.

Energy Equations - Parts Ring

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Who discovered the helicopter?

Rooivalk Attack Helicopter
Rooivalk Attack Helicopter

An interesting question with many answers. Case history tells us that a big drawback in the early design phases was the power to weight ratio of the engines at the time. Leonardo da Vinci drew the plans for a device which used the Archimedes screw, in this case, an ‘aerial screw’ for lifting the prime mover. His models do not show a counter rotor which is needed to prevent the helicopter or flying machine from rotating counter to the screw rotational direction. To cut to the chase there were many ‘inventions’ but none that could really be flown or at least in the modern sense be practical e.g. to be used to lift a considerable weight and fly (or at least be piloted).
1900 – 1920
Jacques and Louis Breguet are credited for being the first to remain in the air in a primitive contraption called the Gyroplane No.1 – however as it was tethered the record remains dubious. This took place sometime around 1907/1908.
Paul Cornu did remain in the air without tether and may be known for being the first to actually pilot a helicopter, however primitive the airframe.
The first vehicle used with cyclic pitch control is credited to an Argentinian Raúl Pateras-Pescara de Castelluccio.
Spaniard Juan de la Cierva – contra-rotating rotors.
Dutchman Albert Gillis von Baumhauer – inventor of the cyclic and collective controls also promoted the further research into helicopter design.
A personal favourite to many however would be Igor Sikorsky’s design, a simple two bladed rear rotor – the first practical and commercial design was the R-4. It’s based on this achievement that Sikorsky is often known as the father of the helicopter although obviously credit must be given to the other pioneers mentioned previously. Sikorsky also had military backing which inevitably expedites any design process. The Germans and Russians had their own program and in many ways this was far advanced to that of the British and Americans in the 1940s. For commercial aircraft however Bell Aircraft were pioneers in their own right and to this day are the benchmark in helicopter design.

DMF or the Dual Mass Flywheel

The relevance of a Dual Mass Flywheel.

There has been a lot of controversy of late, especially as seen over the internet as to why vehicle manufacturers are opting to supply dual mass flywheels over their single mass counterparts when the DMF is known to be unreliable and very expensive. As an owner of an X-Trail I can assure you that the replacement is not cheap – from the supposed sound of a worn release bearing to a full clutch replacement is going to cost you upwards of 2 000 U$ so be prepared.  This clutch by the way had done 144 000 Km and still worked fine. It’s an eight hour job so don’t take it lightly.

Dual Mass Flywheel

The image above is from website – call them 877-525-5233 or email to

An interesting video showing the DMF is shown below.

Fitting the Dual Mass Flywheel


Many fitters claim to be able to skim the flywheel but this is not advisable as the spring around the inner part of the flywheel will in all likelihood be worn. The flywheel will make a noise over time and you may not even be aware of it – once the flywheel has been replaced this will be immediately noticeable, less noise especially doing acceleration. The manufacturer will not advise a user to replace the clutch with a single mass flywheel kit. One of the advantages of the DMF is gear changing and you’ll find many drivers complaining of the conversion kit causing an entire change to their driving habits. I would not know – most of the cars I have driven all had SMF but had no problems in either gear changes or four cylinder vibration. I’d be interested to hear of anyone having done the conversion and whether it was worth it, especially to large capacity 4-cylinder engines.


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