Safe Speed Forums

Airframes have very different metal fatigue problems to cars, as pressurised cabins literally blow up like balloons on every flight.
It's only non-pressurised cabins, such as found in light aircraft, which don't suffer from this.

cheers
Peter

Hmm, thats a good question. Aviation components are generally 'over-engineered' and have an enormous factor of safety built in, i.e. they are 'lifed' very conservatively, must be constructed from specific approved grades of material and are protected from the elements by processes similar to those I outlined above.
Car structures are also subject to some pretty corrosive substance not least road salt. That said, if the paints and laquers used to protect steel body components is sufficient to attract the longeivity benefit we now see in modern production cars, I suppose it would be quite adequate for aluminium as well.



Well pressurization certainly plays a part, but this is just one type of Low Cycle Fatigue; all airframes experience many others. Cars are, as you point out, quite different insomuch as their structure is generally much more rigid than that of an aircraft which must necessarily flex else it would fall apart.
Engines, both Gas turbine and Reciprocating Piston suffer High Cycle Fatigue, a phenomenon experienced by Kimi Raikonnen at the Nurburg circuit

Something I found very interesting was the fact the US Airforce intents to keep its fleet of B-52's bombers operational until at least 2050, which by that time will be approaching 90 years old. That is staggering.

I doubt rust-proof long life vehicles will have any effect on vehicle replacement since it's the rampant depriciation and huge dealer labour costs for an out of warrenty car that means used cars are relatively worthless. This has been increased in part by the slow demise of the back-street garage. This being for 4 reasons, one is the advancement in technology meaning continued investment is needed, two is rapidly increasing insurance costs, three is a reluctance in people to use non-franchised dealers and four is the fact people are more likely to throw a car away then spend money repairing them. All this is conspiring to allow some dealers to charge labour rates of £125 an hour and thats not just the ultra-premium brands either. Parts prices are on the rise as well - theres less interchangeability meaning its less lucrative for pattern manufactures who help keep prices down.

I wonder what effect the inducement the government have given manufactures such as Nissan to set up in this country have effected the price of new cars? Are they too artifically low? Perhaps used car prices would be higher if people had to pay the true cost of a new car?