I have just had a crack develop in a Remis Vario 2 400 x 400 roof light. I have purchased a replacement and fitted it but it is clear that the failure is as a result of poor design and detailing.
The Perspex dome only has an opening mechanism on one side so that when you open it the are twisting forces in the dome, with the hinge nearest to the opening mechanism being subject to the greatest twisting forces. The hinge design has a 90 degree corner, which allows the forces to cause a crack to propagate from the corner of the hinge.
Worth checking if you have them fitted to make sure that there are no cracks developing over time and you don't end up with a total failure. I spotted mine as I heard a crack when I opened it the other day.
However, what have designers learnt from history? Nothing!!
The de Havilland DH.106 Comet fell out of the sky due to stress concentrations around square openings.
Ship sinking die to stress cracking around hatches with square corners.
The Perspex dome only has an opening mechanism on one side so that when you open it the are twisting forces in the dome, with the hinge nearest to the opening mechanism being subject to the greatest twisting forces. The hinge design has a 90 degree corner, which allows the forces to cause a crack to propagate from the corner of the hinge.
Worth checking if you have them fitted to make sure that there are no cracks developing over time and you don't end up with a total failure. I spotted mine as I heard a crack when I opened it the other day.
However, what have designers learnt from history? Nothing!!
The de Havilland DH.106 Comet fell out of the sky due to stress concentrations around square openings.
Ship sinking die to stress cracking around hatches with square corners.
