J. Clarke wrote:
Morris Dovey wrote:
MikeWhy wrote:

Locking against heavy loading would seem to suggest a worm. PV? A
Stirling pumped "hydraulic" motor/water wheel? I know... complexity.

PV plus motor plus worm drive is certainly an attractive route, but
too expensive and not suited for local production and maintenance.

It needs to be really simple and so inexpensive that it's not worth
stealing. For context, rural Somalia might be one of the target
"market" areas.

Offhand I'm not sure how one would design such a thing but rather than
using shaft work could you pump water from one plastic bag to another,
with appropriate levers and paddles resting on top of the bags?

Maybe. I've been too involved in trying to help get the engine working
to worry about the tracking system until now. Nearly all of my past
experience with control systems has been digital, and I'm really in over
my head on this one.

It seems to me that if I can choose one side to pump to, then I should
be able to pump to a cylinder/piston linear actuator of some kind
(thinking of a reworked shock absorber or strut) to do that job.

Hmm - if I use robatoy's gas cylinder idea to control a valve to direct
part of the pump flow to one of your actuators, I might be on a better
track than I am now, even though I'll still need to figure out some
reliable way to make it face the morning sun without being vulnerable to
nighttime gusts.

--
Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
http://www.iedu.com/DeSoto/