Jacob’s Blog

Not much new to say for the month of February. Between being sick for a week, all of the rain, and what little work I’ve had there hasn’t been any significant progress on the tank.

I am hoping to complete construction of the canopy before month end, and then will need to prime/seal it. After kicking around several ideas for raising and lowering the canopy by power I finally settled on a simple block and tackle style pulley system and gear motor. One consideration is how quickly I want to raise and lower the canopy; ideally 20 seconds seems good. The great thing about adding pulleys is the torque on the motor can be reduced by reducing the tension in the cable, but as I have realized overall motor horsepower stays the same and tends to govern the design. Here is why:

Pulleys trade force for distance. The work done will always be the same regardless the number of pulleys used; more pulleys just means more cable to be reeled in. For a given design, the more pulleys, the more cable to reel in, and if the time to raise/lower does not change with the number of pulleys, then the RATE of work stays the same, hence the motor power does not change… So I am currently looking for the ideal gearmotor and working towards finalizing the design. I’m hoping to have everything installed by mid March… check back soon!

Jacob.