DURR wrote: |
it was said on a history channel documentry the blades on the hueys did not last long and had to be replaced every 100 or so hrs flight time if so then the chipping thing is probably minimal because of constant replacements |
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While rotor blades have a finite "life", 100 hours seems somewhat low, especially considering that 100 hours...and more...was flown in a month or less.
The phased maintenance cycle on aircraft is different from type to type, but most types have certain inspections and preventive maintenance required at each 100 hours. This often involves removal and reinstallation of blades or possibly replacement due to condition.
All the previous posts concerning "chipping" are correct, significant dents, or chips in the leading edge of blades are idicative of blade strikes and are usually cause for replacement. The big concern is over leading edge spar integrity. Several methods were used on metal blades to give a visual assesment of spar integrity.
H-3s and CH-53s used to have a "BIM" (I forgot what the acronym stood for) indicator on each blade. This setup was based on pressurizing the leading edge spar...the idea was that if pressurization was lost, then there was a breach somewhere in the spar.
CH-46s and CH-47s used an "ISIS" (integeral spar indicating system) indicator on each blade, it was similiar to that used on CH-53s and H-3s except that it was based on a vaccum existing in the leading edge spar.
The problems of both these systems is that a faulty spar could be indicated when in fact the problem was simply a loss of pressurization or vaccum caused by other than a loss of spar integrity.
Paint erosion on the other hand is a fact of life for rotor blades especially when operating in a field environment and generally doesn't cause any problems. It looks like crap, and the way I used to try to stay ahead of it was by applying Johnsons floor wax to the leading edges of the blades.
HTH
Jonathan Primm