I have been a member of the site for a very short time, but have been engineering and teaching CVT clutching for the past 15 years at the factory level. Many of you have read my tech articles in SnowTech magazine. I enjoy researching and writing about these incredibly complex mechanical devices.
I have read many prior threads on this site involving CVT clutch and belt issues. These issues also exist in the snow industry. To understand how we got here, a short history lesson is in order.
The modern day CVT flyweight clutch was first developed around 1970. The first flyweights were hand-made to develop the cam surfaces we see today. The attempt to share understanding of the working CVT clutch system was first published by Olav Aaen. The first manual was nothing more than a couple of pages, but was popular and first published in 1975. In fact, so little was known about the CVT primary clutch that Olav would sell out every weekend at races in the snowbelt. He paid for all his travels just selling the manuals.
Olav Aaen Is credited with the first patent involving the CVT flyweight design (patent 3,939,720). It was written while Olav worked as an engineer for OMC. The ‘720 patent is very revealing as to the understanding of the technology at the time. If you take the time to read the whole patent, you quickly realize that the patent was written about devises that controlled the flyweight, not on how to design a flyweight. When talking to Olav about his “720” patent, he said there were just too many variables that weren’t understood at the time.
The Aaen clutch tuning manual has just been updated (40th anniversary). The manual currently sells for $35 on his site (Aaen Performance - High Performance products for Snowmobiles and Polaris ATV's), and will be the best money spent for those who want a baseline understanding the CVT clutch system.
The Aaen manual is a great starting point, but for hardcore performance guys the manual really only discusses the end results of changes made to the system. To truly understand how the system works you need to get into the physics of the system. For many years I avoided trying to do this. The CVT system seemed very complex, and frankly nobody (including myself) would touch the subject. “Experts” in the field were just happy to know how to tune them and the science became one of those black arts that was learned over time making the old guys very valuable in the high performance snowmobile business.
I have read many prior threads on this site involving CVT clutch and belt issues. These issues also exist in the snow industry. To understand how we got here, a short history lesson is in order.
The modern day CVT flyweight clutch was first developed around 1970. The first flyweights were hand-made to develop the cam surfaces we see today. The attempt to share understanding of the working CVT clutch system was first published by Olav Aaen. The first manual was nothing more than a couple of pages, but was popular and first published in 1975. In fact, so little was known about the CVT primary clutch that Olav would sell out every weekend at races in the snowbelt. He paid for all his travels just selling the manuals.
Olav Aaen Is credited with the first patent involving the CVT flyweight design (patent 3,939,720). It was written while Olav worked as an engineer for OMC. The ‘720 patent is very revealing as to the understanding of the technology at the time. If you take the time to read the whole patent, you quickly realize that the patent was written about devises that controlled the flyweight, not on how to design a flyweight. When talking to Olav about his “720” patent, he said there were just too many variables that weren’t understood at the time.
The Aaen clutch tuning manual has just been updated (40th anniversary). The manual currently sells for $35 on his site (Aaen Performance - High Performance products for Snowmobiles and Polaris ATV's), and will be the best money spent for those who want a baseline understanding the CVT clutch system.
The Aaen manual is a great starting point, but for hardcore performance guys the manual really only discusses the end results of changes made to the system. To truly understand how the system works you need to get into the physics of the system. For many years I avoided trying to do this. The CVT system seemed very complex, and frankly nobody (including myself) would touch the subject. “Experts” in the field were just happy to know how to tune them and the science became one of those black arts that was learned over time making the old guys very valuable in the high performance snowmobile business.
opcorn:Great stuff, keep it coming...
