Control yoke

Hi folks been a while since I've been on the forum.
I have a set of Mmb parts for a La class submarine.
One of the issues that has had me stumped has been the control rods for stern planes and rudder, as the Sub has a central drive shift for the prop, how do you manage to have the control rods assembled around the shift?
Also has anyone bought any parts from the rc-sub-workshop on eBay, they are in Hong Kong.

David

Thanks I see the idea now, are those bought fittings, or made by yourself?

dgp1957 wrote:Thanks I see the idea now, are those bought fittings, or made by yourself?

I first make a brass master, pour a rubber tools around the master(s), then spin-cast white-metal parts.

Thanks, do you sell these as fittings?

David

dgp1957 wrote:Thanks, do you sell these as fittings?

David

Nope.

David

Guys, this may sound (and probably is) a daft question, if a model sub uses a static dive system it shouldn't need the dive planes to operate, is that correct?

Even a static system will use them. Granted not as much, but you may need the control if say your dive system does not respond and you want to surface. While there are times you can get that perfect neutral buoyancy, other influences like temperature or water density can create a close to neutral buoyant. It will either slowly raise or sink as time goes by. Your dive planes can help. Another point is a big boat is coming at your sub.....you want to get deeper fast. The planes will help there too!

Yes, at zero or low speed, buoyancy (hydrostatic) forces are the most significant forces acting on a submarine. Once you get past a particular speed, planes, hull shape and the hull angle of incidence  start to dominate as dynamic forces. So dynamic forces can compensate for hydrostatic forces as in a "dynamic diver."

I don't know why it is helpful to think of but, imagining  how an airship or blimp is controlled helps me understand it. (My thanks to David Merriman for that analogy.)

David

dgp1957 wrote:Guys, this may sound (and probably is) a daft question, if a model sub uses a static dive system it shouldn't need the dive planes to operate, is that correct?

technically you are correct. I own a scale model of the Alvin DSV2, and it does not have dive planes. its buoyancy is entirely controlled by its ballast tank.

having said that, everything the others have pointed out is true, which basically means that i am lucky the Alvin does not move fast, or dynamic forces would overtake the limited control i have over depth.

(Almost) any hull form moving through water will see hydrodynamic forces acting upon it to cause movement in a direction that is not aligned with the parallel axis of the boat. The crazier the hull, the more you'll see evidence of these forces. A modern nuclear boat... pretty small. An old fleet boat, or a fantasy boat like the Nautilus from 20,000 Leagues or the SeaView?... oh yeah! Big time!.

Without planes to counteract these forces, no amount of precision trimming via your ballast system will be able to keep the boat at a stable depth. Additionally, ballast system can rarely react quickly enough to counteract these forces. That's where the planes come in. The other thing the planes do is allow for pitch control of the boat, giving you the ability to "crash" dive or surface quickly, or counteract these off-balancing forces that want to pitch the boat off its center line.

A nicely trimmed boat, tanks vented to neutral buoyancy, and with some decent control surfaces to effect change, is a beautiful thing to operate. Get your trim wrong or have insufficient surface area or throw on your planes and it can be like wrestling a snake...

Bob