Strange coincidence?
Have just finished reading Capt Eric Brown's book entitled: "The helicopter in Civil Operations".
One of the topics where he expressed some optimism in the further acceptance of helicopters was the 'breakthrough' made by NASA researchers who had been working on a Multiroller Traction Drive for the past 10 years.
The book was published in 1981!!
The advantages, back then, were deemed to be:
1. Quiet, almost vibrationless means of transmitting power.
2. Simpler and less expensive to manufacture than helical or planetary gears.
3. Lighter and smaller than conventional gear boxes.
4. As efficient as toothed-gear system.
5. Higher reliability and are less susceptible to breakdown and wear than conventional gear boxes.
It was envisaged that roller drives would enter the realms of in-service practability in the mid-1980s!!!!!
So who's got them?