What does daN mean in weight terms?

The brochures I have for various Paragliders state the permitted weight range in a measurement called daN. What is daN? Example below

All up weight (DHV) 55-90 daN All up weight (Afnor) 60-78 daN

Any ideas?

1 daN = 1 deca Newton = a force of 10 Newton 1 N = 1 Kg.m/s2 (F = M.a, force = mass x acceleration) 1 kgf (kilogramforce) = 9,80665 N So on earth a mass of 1 kg is attracted with a force of approx. (depends of your location on earth) 9,80665 N or 1 kgf, this force is also called a weight of 1 kg. In other words 55-90 daN = approx. 56-91,7 kg 60-78 daN = approx. 61-79,5 kg

Why the floppymanufacturers would use daN (= approx kilograms) eludes me..

Happy?

Because they're European...?

Yea happy now... so it's roughly the same as kilograms. Thanks

Andrew

because it's only a 2% approximation ... that's quite good !

I think it's some engineers being pedants, not that I would know anything about that . I think it's all about the difference between mass and weight. The Pound and the Newton are measures of weight, the gram is a measure of mass.

Weight is the force caused by the action of gravity upon a mass. So in space, you're weightless (sort of), but not massless.

So perhaps the manufacturers are covering their backs in case you fly the wing on a planet with higher gravity...?

CE standards require labeling of force in units of force (newtons). We are wholesalers of mountaineering equipment. All of our equipment carries the CE mark and is labeled in kilo-newtons.

One of the first things I have to educate my customers about is what the heck those numbers are about. I always tell them to approximate 1 kg = 10 newtons (1 daN). A typical 'D' aluminum carabiner carries a rating of about 22kN.

To be pedantic. They weren't German, by any chance? ;^)

Weight is an ambiguous word. It actually means mass more often than it means a particular kind of force. The 'net weight' in the grocery store, for example, is quite properly measured in grams, and newtons would be improper.

The strangeness that provoked the question 'Why?' wasn't the use of newtons, but the silly choice of prefixes. Why not newtons or kilonewtons instead?

There is a preference for the prefixes which are powers of 1000, a preference that didn't start with SI but actually was there even in the cgs predecessors of SI (except of course for the base unit which used

Kilonewtons make sense. Dekanewtons do not.

Actually ( at the risk of being another pedant ;^) I think that you will find that the gravitational force is measured, and the mass which is displayed is inferred from that.

Which goes to show that in most situations, Newtons and Kilograms(x~10) can be, and are, used interchangeably. Scales have traditionally ( and properly, as you point out ) given values as a mass, which is why that unit system should have been used, for convenience, with no real loss of correctness.

To answer your question, I can only assume that it is for the approximate equivalence of the 2 units. I agree that the choice of prefix is also silly.

For any Americans out there that think that this confusion between Kg and N is some silliness in the metric system, I would like to point out that when you look into it, the imperial system is even more flawed! A 'pound' can be either a force or a mass, and it is not necessarily clear which. Look up the units 'poundel' and 'slug' if you are interested.