Bronco Type XXIII in 1/35th scale

[Subculture]

Have got zero experience of Type XXIII, but lots of experience of Seehund which is very similar in hull design, like a baby Type XXIII. I ran that minus a leveller for several years, because you couldn't purchase one, and I didn't know how to make one, and it was a very easy to drive boat.

So maybe worth disconnecting the leveller altogether and see how it drives on manual.

[He Who Shall Not Be Named]

What happened to make it simple?
Proven hull. Probably more rc running time than any other sub here in the states. There were tons of 32p type 23's running in their day.

D

I know. This is killing me. Simon's 23's worked great. And, as you indicate, so many have had no problem driving these things. Yet me, Mr. know-it-all (and, I do!) can't get this 1/35 Bronco 23 to play nice. Argh!

M

[ffr2608]

What happened to make it simple?
Proven hull. Probably more rc running time than any other sub here in the states. There were tons of 32p type 23's running in their day.

D

[He Who Shall Not Be Named]

If that doesn't work. Might I suggest doing some flow pattern analysis around the hull.
A water tunnel or tow tank would be best but tuffs of cotton taped around the hull and a fan would do the trick.

BTW, can you show us q video of the XXIII porposing. Watching it can help analyse whats causing the problem.

...yeah, I'll get right on that, Mr. Wizard!

M

[redboat219]

If that doesn't work. Might I suggest doing some flow pattern analysis around the hull.
A water tunnel or tow tank would be best but tuffs of cotton taped around the hull and a fan would do the trick.

BTW, can you show us q video of the XXIII porposing. Watching it can help analyse whats causing the problem.

[He Who Shall Not Be Named]

Good stuff there, Steve.

I'll first try another angle-keeper. But your lock-the-stern plane idea has merit. Food for thought. Thanks. We'll find the problem.

M

[Warpatroller]

Yours is the first XXIII model I've ever heard of having a porpoising problem.. It seems unlikely that the cause of the problem is due to the hydrodynamic form of the XXIII model itself. It has always been referred to as a well running model by its owners. I've even seen small 1/72 scale versions running with out porpoising while submerged.

Only thing I can add is that your stern dive plane throw of 40° to 50° is rather aggressive compared to the real boat. As you can see in the diagram below, apparently, 26° was the throw on the full-size boat. With 25° on the rudder.

How about this test for the pitch controller (angle keeper). Disconnect the angle keeper from the stern planes and lock the stern plane pushrod into a neutral position, leveling the planes. Run the boat that way and see if there is a noticeable decrease in the porpoising phenomenon. If so, I would think something is not right with the angle keeper device.

The hull itself is a sound design, so it must be some sort of control related issue.. It would be disappointing to find that this boat doesn't perform as well as the 32nd Parallel model. All that work and with such a nice scale propeller that you made, there has got to be a solution!

Steve

[He Who Shall Not Be Named]

Yeah Darrin, same thing for me.

Just got back from running the Bronco 1/35 Type-23 at the pond -- same problem. Is was not control surface over-response. Damn! Still chasing this problem.

M

[He Who Shall Not Be Named]

Dave,
My epoxy 23 kit drove like a dream. I had the stern planes on an angle keeper and drove with the bow planes. I never had any control of the stern planes.
Might not be what you wanted to hear.

Darrin

Just what I wanted to hear. I'm doing something dreadfully wrong here. You're good experience with the hull-form points to this being a control issue, not a hull-form issue. Good stuff, Darrin. Thank you so much.

M

[goshawk823]

Dave,
My epoxy 23 kit drove like a dream. I had the stern planes on an angle keeper and drove with the bow planes. I never had any control of the stern planes.
Might not be what you wanted to hear.

Darrin

Yeah Darrin, same thing for me.

[ffr2608]

Dave,
My epoxy 23 kit drove like a dream. I had the stern planes on an angle keeper and drove with the bow planes. I never had any control of the stern planes.
Might not be what you wanted to hear.

Darrin

[redboat219]

Can't wait for the result.

[He Who Shall Not Be Named]

Dave, if you remember I had the same problem with the Albacore for a while. Your suggestion helped me to resolve it. If its giving you trouble.............heaven help us.

Yeah, Mark. The first things I did was to move the c.g. forward. But the boat continues to dive uncontrollably, or rise uncontrollably. I blame you!

However, during this morning hideous walk (off toilet, my best thinking time) I came up with a likely cause of the wild porpoise acton evidenced by this god-forsaken 1/35 Type-23 kit: too much throw on the stern planes.

As originally set up, there is as much as 50-degree deflection on rise and almost as much in dive. Most control surfaces working a non-compressible fluid stall out at about 40-degrees to flow, and I think that situation is at the heart of the submerged underway pitch problem -- the stern planes are stalling out and providing only drag, but no pitching force at or near full deflection. What kind of dumb-ass puts a boat in the water with throws like that?!

An hour ago I reworked the stern plane linkage and now have it throwing no more than 40-degree deflection rise and dive. I'm filling Ellie's pool ... er .... test-tank for a final trim, then off to the local bug infested, disease saturated swamp to see how this piglet runs now. Film at Eleven, folk's.

M

[greenman407]

Dave, if you remember I had the same problem with the Albacore for a while. Your suggestion helped me to resolve it. If its giving you trouble.............heaven help us.

[He Who Shall Not Be Named]

Yet, observation of others Type-23's reveal a hull form that maneuvers very well underwater -- mine the exception at the moment. But something to think about, Romel.

M