today's work

[He Who Shall Not Be Named]

Hey David? Do you have another boat you could drop the Type XXIII cylinder into, just for ****s and grins? Just to see how it behaves in another hull?

I do. An almost completed 1/96 STURGEON. But, I have many obligations (I'm teaching regularly now) to address so I want to clear those off the table first. Still 'legacy building'. The Type-23 has been banished to upstairs storage, and the cylinder has been post missioned and socked away in the shop 'ready service' pooka under the heavy-duty bench.

[MFR1964]

To my opinion it has to do with the CG and the hydrodynamics of this hull, like Andy stated it's design is made around that, mine only takes the dive at higher speeds, want to take the AFD out, just to see what the result would be.
Leaving the model alone at this point is a good decision, did the same with the Ko Hyoteki, had to dive her up from the swimmingpool at Germany,, i hate that, for now she will be a static model untill i find working solutions for this model, some things work another things not.

Manfred.

[goshawk823]

Hey David? Do you have another boat you could drop the Type XXIII cylinder into, just for ****s and grins? Just to see how it behaves in another hull?

[He Who Shall Not Be Named]

Slots won't make much difference, a little drag but that's all. Moving the the c.g/c.b aft will make the boat less stable, as the c.p is dialled in by the design, and that should always be behind the c.g for stability.

All these boats are the same, and with the original configuration largely the same as other Type23's, then by deduction the issue must lie with the hydroplane control.

Agreed, Andy. If I ever revisit this boat, first thing I do is, as you advised, and take the angle-keeper out of the loop.

[Subculture]

Slots won't make much difference, a little drag but that's all. Moving the the c.g/c.b aft will make the boat less stable, as the c.p is dialled in by the design, and that should always be behind the c.g for stability.

All these boats are the same, and with the original configuration largely the same as other Type23's, then by deduction the issue must lie with the hydroplane control.

[redboat219]

Would be great to have access to a hydrodynamic test facility to test the theory on David's actual boat or the 1/144 scale Type XXIII modified to mimic David's.

[redboat219]

There were a few running at Subfest that did not seem to have the problem... Just something about your boat perhaps.

I wonder if the modifications David did to the limber holes on his boat has some effect?



Like the holes in a flute, cover one and the pitch changes.

Maybe repositioning and changing their size results in some turbulent flow which causes the oscillations

[He Who Shall Not Be Named]

Ugh, not something I wanted to hear. Don't know what to think about it except proceed on my XXIII and hope for the best. There were a few running at Subfest that did not seem to have the problem. Steve's I think. Just something about your boat perhaps.

I'm looking forward to your results. If they are good, then do chronical all pertinent information as to c.g-c.b. placement, amount of fixed ballast weight, etc. I would apply all those conditions to this screaming pile of **** I'm currently burdened with.

[He Who Shall Not Be Named]

Still got the see-saw effect with the leveller disconnected?

Didn't try that. If, and when, I ever re-visit this boat I'll try that. Thanks, Andy. Right now I have to distance myself from that project... or someone's gonna get hurt!

[Ken_NJ]

Ugh, not something I wanted to hear. Don't know what to think about it except proceed on my XXIII and hope for the best. There were a few running at Subfest that did not seem to have the problem. Steve's I think. Just something about your boat perhaps.

[Subculture]

Still got the see-saw effect with the leveller disconnected?

[He Who Shall Not Be Named]

Tested the Type-23 at the lake yesterday. Terrible results, u/w pitching is the worst yet. This is the third longitudinal change in c.g.-c.b. location on this boat. The hull goes into storage and the WTC will be re-purposed eventually. Total frustration. I don't have a clue as to what I'm doing wrong with this particular hull. Total defeat on this front.

[Subculture]

They all tend to operate on the same principles- accelerometer chip linked to a microcontroller, with adjustable gain sometimes continuously variable via a small trim pot or in steps by jumpers or button presses, and finer tweaking via the servo arms.

[redboat219]

What if you try a different brand like Engels, Microgyros or the old Subtech levellers?

[biggsgolf]

I tend to agree with you, Andy; seems that the evidence points its bony finger of guilt at the angle-keeper. After this Sunday's deep water run, after this severe c.g.-c.b. change, I still get the wild pitching underwater, I'll swap out the angle keeper with a different unit. Your input always welcome, pal.

Yup, that's why I asked you what sensitivity it was set to