With regard to 'O' rings I agree they were not designed for the task but they work extremely well regardless. The things to bear in mind are:
Don't use rings that are too thick as they do not like being deformed from the circular and will not stretch much. Thinner ones are more flexible and forgiving and perfectly strong enough.
When fitted, keep the rings as circular as possible, stretching them simply ramps up the friction and makes them inefficient as well as putting stress on the bearings. It is simple to 'tune' them using an ammeter and a low voltage supply to the motor.
It is surprising how little tension is needed to give a strong, non slip drive. Get it right and you are simply twirling the pulley round rather than compressing the belt and this puts very little stress on the bearing.
Almost all the models I have built over the years have used belt drive of one type or another and they have all proved to be reliable and very efficient in power consumption when geared down. What's not to like?
For a multi screw setup pulleys and belts are rather cheaper than purchasing extra motors and couplings and offer significant gearing advantages while direct couplings are inherently inefficient for the reasons described in my other posts and the slightest misalignment in any dimension introduces friction and a tendency to open up the shaft bearings.
As John says, ideally roller bearing shafts should be used, but in the low RPM low power applications of most scale models it simply isn't necessary in practice. And bear in mind that at the other end of the shaft we accept that there is a propellor which is generating sideways thrust against the bottom bearing and nobody worries about that do they?
Colin
Author
Topic: 2 MOTORS DRIVING 4 PROPS SHAFTS ANYONE KNOW HOW ? (Read 5856 times)