> so why is their service life so much shorter than some planes have had?
The lifespan is typically 20 years unless there is a catastrophic failure (huricane, typhoon, manufacturing error, etc). There are some major differences in how turbine blades and airplane wings behave:
- A wind turbine blade suffers gravitational, centrifugal and aerodynamic loads about 10 times per minute, 2500h - 3000h/year. These forces can be up to 20kN[0]. (vs. plane only accelerates for take-off and landing very few times a day, and is otherwise is a relatively steady load regime)
- Wind turbines are often in remote locations, and maintenance can't happen every time they come to an airport (predictive diagnostics by embedding sensors in the blades is starting to change this)
Generally, fibre reinforced polymers are great materials for the job and there are a variety of applications for the recycled fibres (filling for new blades, downcycling, architecture, etc [1])
I'm confused. Why do you think that planes have a longer lifespan?
I mean, I assume we're talking about plane propellers here, right? Not airframes or something? Are you sure that a plane would fly with the same blades for more than the cited 10-25 years?
I'd also be a bit skeptical about their structural integrity. Composites usually have dimensional strength with weaves going in orthogonal and diagonal to each other. However, any holes, or stress cracks would make their recycled use for less critical applications. I would like to read further on how they inspect and possibly recondition them for less stressful use, but within the parameter of re-purposed, safe use.
It's been a while, but I used to work with some folks who performed maintenance on helicopters that had composite rotor blades - and they were constantly being inspected and sent back to the manufacturer.
Perhaps it's different in the civilian aerospace world, but I don't think it's sensible to expect those blades to last as long as the airframe.
The lifetime of composite rotor blades is shorter than metal based rotor blades that were used in older generations of helicopters.
Example:
The B0 105 helicopter is cleared for up to 3.5 positive G force and one negative. Its agility and responsiveness can be partly attributed to its rigid rotor blade design, a feature uncommon on competing helicopters.
The rotor system is entirely hingeless, the rotor head consisting of a solid titanium block to which the four blades are bolted; the flexibility of the rotor blades works to absorb movements typically necessitating hinges in most helicopter rotor designs. The reliability of the advanced rotor system is that, in over six million operating hours across the fleet, there had been a total of zero failures. One benefit of the Bo 105's handling and control style is superior takeoff performance, including significant resistance to catastrophic dynamic rollover; a combination of weight and the twin-engined configuration enables a rapid ascent in a performance takeoff.
The MBB Bo 105 is the only heli cleared for acrobatic stunt flight and is the work horse of "Flying Bulls" (Red Bull).
so why is their service life so much shorter than some planes have had? Seems the idea behind their structure should not be too far off.