Engel Kits Experience

[Oldus Fartus]

Is anyone familiar with the Engel Model Sub Kits?

How does the Ballast System work?

[JWLaRue]

OF,

How much detail are you looking for? The Engel kits use one or two pistons as the ballast system.....think a big motor-driven syringe. They offer several different electronic modules that are used to control the amount of water that is taken into (and pushed out of) the piston.

I believe that (most) everyone would agree that a piston-based ballast system provides the best level of control and repeatability of the ballast volume.

-Jeff

[Oldus Fartus]

OF,

How much detail are you looking for? The Engel kits use one or two pistons as the ballast system.....think a big motor-driven syringe. They offer several different electronic modules that are used to control the amount of water that is taken into (and pushed out of) the piston.

I believe that (most) everyone would agree that a piston-based ballast system provides the best level of control and repeatability of the ballast volume.

-Jeff

So does the piston based system need surface air (snorkel) to operate or does it simply draw water in and out of a ballast tank with a piston?
Pete

[Ralph --- SSBN 598]

Piston systems...
draws water from outside the water tight cylinder through a hose and compresses the air inside the water tight cylinder.
Then expels the water back to the outside and the compressed air in the cylinder becomes normal again.

here is an old web page that describes several ballast systems including the piston system.

[JWLaRue]

...or you can go to our own "R/S Sub School" here to see information as to how the various ballast systems work:

http://www.subcommittee.com/rcss-ballastsystems.html

-Jeff

[Oldus Fartus]

Gentlemen,
Thanks for the info and also for pointing out "sub school"...should have gone there in the first place!
Pete

[Ralph --- SSBN 598]

Lookie there, I learned something today.
I did not know SC had this section.
I guess I should go to the main web site once in a while.
Thanks, Jeff....

[Chuck]

My very first RC sub was an Engels kit of the Patrick Henry SSBN. It was a long time ago, when dinosaurs walked the earth, and it had two pistons ballast tanks in it. To say that it was built like a tank would be an understatement, because the hull becomes the WYC and the whole thing has to be able to withstand both positive and negative air pressure as the ballast tank pistons move to and fro. The quality of the fiberglass is very good, and the engineering is first class, as you would expect from a very experienced German company. After a few years of humping the sub back and forth to the lake I decided to save my back and converted the whole thing to a wet hull, WTC, 12 volt system boat. The ballast system has gone through several iterations over the years, but has been a SNORT system for several years now, working very well. I made the infamous Z cut into the hull for easy access to the internals, and have had zero problems with it. It is still just about my favorite model sub, thirtyfive years after I first built it. The primary challenge with the dry hull piston boats is that they are very, very heavy, and tend to be power hogs, but Engels makes first class model boats, and their customer service is tops. By the way, piston systems still seem to be the ballast system of choice in Europe, but have largely been replaced by the wet hull, lighter WTC's in the U.S.

[JWLaRue]

....and tend to be power hogs....

This is an oft quoted aspect of piston ballast systems, but my experience with them is just the opposite. While it is true that while operating the piston, there is a good amperage draw, unless you spend the entire time making the piston go in and out you aren't going to have *that* much affect on overall running time. When you also take into account the newer battery technologies (e.g.: NiMH and LiPo) you are more than likely to get bored running a dry hull, piston boat before you run out of power.

Finally, if the weight of a dry hull is a bit much to handle you could do what I did: put the piston in a dive module. You get the benefit of the controllability of the piston and the lighter weight of a wet hull boat.

-Jeff

[Guest]

The 6volt Engel tanks use a pretty meaty 540 motor. It's not necessary to have such a large motor, I changed some round to 12 volt 385 motors, and they run the tanks at the same speed and half the wattage, but with sufficient reserve to push the piston against about 40psi, far more than the boat would ever see in practice. So I could almost certainly use smaller motors if I chose to.

V-thread jackscrews are only about 20% efficient, but you only tend to see that inefficiency under higher loads. In reality our subs rarely see more than two or three psi, so the tanks don't have to work against much load, and draw just a handful of watts. My own tests concluded that piston tanks are pretty efficient when compared with systems based on onboard compressors or water pumps.

The main issue with piston tanks for many modellers is obtaining the right size for their model. If you build medium to large models there's a decent choice, but for smaller models less so. The alternative is scratchbuilding, and details have been published on how to roll your own. You do need a lathe though.

[Oldus Fartus]

...or you can go to our own "R/S Sub School" here to see information as to how the various ballast systems work:

http://www.subcommittee.com/rcss-ballastsystems.html

-Jeff

For some reason the video associated with Piston Tank Systems is a private YouTube video?

[PaulC]

Apparently the owner changed the status of the video. It used to be public.