Pull-Down Motors - How to level boat with pull down motors

[gascan]

I'm planning on building a sub using one or two motors to pull it down to dive. I plan on using an ESC (like the MTroniks Marine ECO ESC) or similar to allow control over depth. I also want the boat to remain level as I dive. I've been looking at auto leveling devinces, but I'm not sure if they would be able to work with the ESC. Any thoughts on this?

(It is an unorthodox method of diving, but it would work. I just want to find out what I can use with it.)

[safrole]

It seems you would need

It seems you would need a pitch controller that has two ESC outputs. I don't think that exists.

Maybe you could use a regular pitch contoller, with a servo. The ouput of this servo could do one of two things.

First it could either physically block (partially) one pulldown fan or the other to vary the balance of thrust. One fan is "perfect", but has a sliding plate controlled by the servo that chokes it off as necessary, while the other fan is either less powerful or constructed less efficiently by means of a more restrictive enclosure or lower pitch blade, etc.

The other thing, depending on how these pulldowns are secured, would be to install at least one pulldown on a pivoting axis. The servo rotates one pulldown and reduces the downward thrust vector, but trades it for a sideways vector. This might be easier to build but could walk sideways a little while diving.

Your best solution would depend heavily on the layout of this boat. Is it anything scale?

[gascan]

If there's a pitch controller

[color=#000000]If there's a pitch controller with one esc output, I think that would be enough. Use two motors, one primary (to control the depth of the boat with a regular ESC) the other one secondary (using the pitch controller to keep the boat level). Even if the pitch controller only has a servo output I could probably still use it.

It is to be as close to scale as I can get it. Specificaly it's the Japanese I-400 in 1]

[bob the builder]

Why don't you use an

Why don't you use an auto-trimmer such as the APC-3 or 4 as a stand alone device rigged to your aft planes and then run your depth control from the proportional channel on your radio?

If the pulldown motor is mounted at the boat's center of bouyancy, it should not be affected when it dives (overly much, at any rate). While underway, you should get decent control of pitch through the automated pitch controller.

Sounds simple enough to me, in theory. Have to watch that the pulldown motor doesn't create too much drag at higher speeds, or you might be looking at an unrequested dive situation.