Self-driven "cutter"

Many of you have come up with and built great "cutters".
Some of these have been very nice.
The problem with all that I have seen is that they require additional control circuitry or air lines, associated complexity.
All to produce a simple "break" in the fountain action !

As a result, I am thinking of a "self propelled" cutter which is one that is driven by the water pressure exiting the fountain nozzle.

Here is an every day example of a self-propelled "cutter" which is quite common and all of you are familiar with -

http://www.diytrade.com/china/4/products/3694425/6005-4_-3_4_plastic_impulse_sprinkler_with_female_connector.html

The oscillating mechanism of this cutter is driven by the water stream exiting the sprinkler head and is forced back into the water stream by the large spring.
The two oscillate at a rate determined by the water pressure at the nozzle AND the mass of the counter-weight.

One idea I have is a circular "screw" like this - http://www.aviastar.org/helicopters_eng/vinci.php
(credit to Leonardo for his great thinking !)

Of course for our purposes, the "screw" would have to have an opening in it, to allow the fountain to pass through it occassionally.
Like the sprinkler example, this mechanism would have specific constants which are "built" in to the design.
The "on" time of the stream would be determined by the size of the opening in the screw and the speed at which the screw turned.
The rotational speed of the screw would be determined by the pressure of the fountain stream. The drag of the fan on its bearings AND the angle of incidence the screw blade presents to the stream of water.

If such a design could be optimized in a reasonable amount of space, it would greatly simplify the "jumping" effect albeit with a pre-determined and unchanging period.

Do any of you know of any attempts at a purely mechanical cutter ??

Thanks in advance !

Nobody here has attempted that (or at least notified us).

Yes, I agree that the other methods or electronics, or pneumatics are combersome. After trying it out, it's not that bad. If you have a desire to learn (or would like to learn) I would suggest giving it a try. There are a lot of cool new controllers and such that can be very helpful. One such controller is the arduino. It's open source so there are a lot of people doing some great things with them.

If you don't want to tackle that I don't blame you. I think your ideas of a pure mechanical cutter have merit. I think either one of your ideas could work.

THanks for the reply, John -

I'm not worried about tackling the electronic cutter idea - just curious if something self-contained could reasonably be fashioned.
This is a great hobby that has so many possibilities !