Hiss Drive Equatorial Platform

[ZEbbEDY]

anyone made one of these before, a box and an inner tube, looks doable 

http://www.tomfangrow.com/hissdrive.html

[knobby]

Looks interesting but I'd feel very deflated if it didn't work :-)

[Rustysplit]

Oh that is genius! You have gotta love the pure simple idea behind that.

[Lux1]

I've made one. It worked very well at moderate magnifications. I then broke it up for firewood when I brought my GOTO mount.

[Moonshane]

I don't really understand how this works but it clearly does. can anyone summarise?

[russellhq]

I wonder if a similar system could be made with water? No need to use a pump if it could.

[Peter Drew]

You would have to change the the title. 

[knobby]

I don't really understand how this works but it clearly does. can anyone summarise?

It's a simple eq platform but instead of being driven as such it's gravity fed as the inner tube slowly deflates ...

Now I'm thinking was Shane asking in jest ? And am I now looking stupid ...

[Moonshane]

no it was a serious query. an equatorial platform drives from one side of a conical section to another. but this will surely drop from the top to the bottom as the tyre inner tube deflates. actually in thinking about it, I have sussed the mechanism. the hiss drive does indeed drop but presumably also as part of the same conical section, just vertically rather than horizontally - it makes no dofference of course.

the final thing I don't get is how the arc is controlled?

[knobby]

If you look at the bottom photo it's like a barn door tracker ... The weight of the ota pushes down and the inner tube deflates at the rate you choose with a regulator valve

[Moonshane]

ahhh, I see, there's a hinge on one side. seems to be a good idea. might try to make one.

[markse68]

zombie thread resurrection sorry, but that is quite brilliant 😀 Bit of a pain to have to re-inflate it after an hour and it adds a lot of height but what an ingenious solution- right down to the air damper for damping out the springy vibrations you'd get. Fantastic

Mark

[globular]

Peter Drew's comment on a possible water variant also deserves this thread's resurrection. 

[knobby]

On 26/03/2014 at 21:04, knobby said:

Looks interesting but I'd feel very deflated if it didn't work 🙂

Finally ...6 years and it gets a laugh 🙂

Thanks @kbrown