Need advice about range of motion...

[modelnut]

Guys,

This might seem like a silly question. But what exactly is the range of motion for rudders and diving planes?

Intuitively, I am guessing a maximum of 0 to 45 degrees. Anything beyond 45 degrees would seem to be overkill. Right?

But should it be less?

-Leelan

[safrole]

My twin rudders go past

My twin rudders go past 45 degrees. Past 45 degrees your net thrust probably drops off at an exponential rate, like a stalled airplane wing.

[anonymous]

Optimum turning is 35 degrees

Optimum turning is 35 degrees left or right, up or down. In some original general arrangement navy drawings if available to the modeler of his/her building subject, check the angle range if shown to be different. Sometimes bow planes will have a slightly greater up angle and a slightly smaller down angle for example. In models, the important thing is to make sure your servos can operate to those angles freely, and then adjust your R/C model's handling accordingly. Other factors could be center of buoyancy, center of gravity in influeancing angles of bow planes for example. Rudders? Always 35 degrees. Like the earlier comment, past a certain angle....your lifting control surface will begin to 'stall'.

There are no silly questions...only silly people. LOL

Steve

[modelnut]

Thanks very much!

It is strange

Thanks very much!

It is strange the way this makes sense. Probably comes from what little I remember from high school physics about adding force vectors.

And it also makes sense that the bow planes might need more "oomph" since they are farther from the propulsion.

I got that from John Dutton. He mentioned that on his first R/C NAUTILUS ( a la Verne and Sharpe) his aft diving planes were too far forward to be effective in keeping his boat level.

Since aft planes are nearer the action that should make them quicker to respond and so their deflection gives more bang for the buck than the bow planes. Therefore they don't need as great a range as the bow planes.

Thanks again!
-Leelan

BTW I am beginning construction of my own NAUTILUS. This is the mark III. The first two had major flaws.

[mike byers]

Stern planes are also typically

Stern planes are also typically larger than bow/sail planes.
This means that they are the primary pitch control of the boat; Bow/sail planes being the depth controlling surfaces.

From an old diver and driver

regards

[modelnut]

The stern planes on Greg

The stern planes on Greg Sharpe's NAUTILUS plans are much smaller than the forward planes. It gives the sub a more animalistic appearance. I haven't heard of any complaints about them other than from John Dutton who placed those same small planes near the propeller.

I guess fish don't need stern planes.

On the other hand, a whale's flukes (aside from the humpback) are much bigger than their pectoral fins. But, then again, the flukes are the propulsive organs - whales have no propeller.

Very interesting...
-Leelan

[mkeatingss]

The TAB for a 637

The TAB for a 637 class boat gives plus or minus 37 degrees for the stern palnes and rudder, and plus or minus 22 degrees for the fair water planes.
Mike

[PaulC]

Mike,

That's a really interesting confirmation.

But

Mike,

That's a really interesting confirmation.

But wait -- didn't the 637 sail planes rotate 90 degrees for under ice surfacing?

[mkeatingss]

Yes they did rotate 90

Yes they did rotate 90 degrees for under ice penetration. But that system is a hydraulic cylinder on the control rod. If the planes were set at 0 (normal proceedure was to lock them at zero in preparation to surface under ice) the planes got to 90 when the cylinder is activated.
If the planes are at 2 degrees up, the planes go to 92 degrees when the cylinder is activated. Kind of an on/off thing. But, as I remember, there were interlocks that prevented the system from being activated if the planes weren't on zero. And to prevent the planes from moving while the under ice system is active.
Mike