Bronco Type XXIII in 1/35th scale

[He Who Shall Not Be Named]

Don't tell me I'll need to cancel my Type 23 order from my local hobby shop!

I think you should get your hands on a stable working 32nd Parallel Type 23 and look how it's laid out.

Might be a good idea till I work out what's happening here. Maybe you should go with the Welsh conversion?

M

[MFR1964]

The only thing i had noticed in the books, is the fast divingtime, if done too quickly you could loose your boat.

David, where is your CG located, still far away from the middle?, if so, try to get it under the conningtower, when you have succeeded that, place two pieces of styrodure foam high inside your tower, and run her again.

Manfred.

[redboat219]

Here's David Welch's Bronco Models Type 23 conversion.

https://www.youtube.com/watch?v=rS9UIffOD6k&feature=youtube_gdata_player

As you can see he's driving without the torpedo tube shutters in place.

[redboat219]

Don't tell me I'll need to cancel my Type 23 order from my local hobby shop!

I think you should get your hands on a stable working 32nd Parallel Type 23 and look how it's laid out.

[He Who Shall Not Be Named]

Just got back from a trial run with tape covering the open torpedo exit points. Not a Tinker's bit of difference -- still dives uncontrollably above a critical submerged speed. I'll play with the stern plane linkage some more, but I'm out of ideas, boys and girls. I hate this boat!!!!!!!!

Gotta hang it up and get back to production work before Mike skins me alive.

M

[goshawk823]

You would think. But, obviously not.

Just got back from running it with the corrected thrust line. No change. Pitches down when underway in submerged trim.

Now, one thing I'm doing that most don't do: The two big square holes where the shutter doors normally fair in with the hull are not present on this model -- I had planned to later equip it with practical torpedoes. Maybe that is contributing some sort of turbulence that works to push the bow down. I'll check it later in the day when the heat dies down a bit.

M

That sure seems like it could contribute to pushing the bow down... them's two big holes.
-sam

[roedj]

I don't know the answer to this question but does anyone know if the original Type XXIII had trouble with the same problem?

Dan

[He Who Shall Not Be Named]

Shouldn't the angle keeper counteract that downpitching?

You would think. But, obviously not.

Just got back from running it with the corrected thrust line. No change. Pitches down when underway in submerged trim.

Now, one thing I'm doing that most don't do: The two big square holes where the shutter doors normally fair in with the hull are not present on this model -- I had planned to later equip it with practical torpedoes. Maybe that is contributing some sort of turbulence that works to push the bow down. I'll check it later in the day when the heat dies down a bit.

M

[redboat219]

Shouldn't the angle keeper counteract that downpitching?

[goshawk823]

no sir. we're helping our daughter move that weekend.
-sam

[He Who Shall Not Be Named]

My fault there, Sam. I started that chain-of-thought in Manfred's thread.

You going to make the SC SubRegatta?

M

[goshawk823]

Thanks, David (and Gene). Hopefully you'll have better news later from your modification.
regards,
Sam
My apologies to Manfred for stepping on his thread as well...

[He Who Shall Not Be Named]

Sam, and you other guys who have just come to realize that the King has no clothes on:

As I said over at Manfred's Type-23 conversion thread, Gene Berger suggested that my problem with the constant wild pitching down of the boats bow in submerged trim might have something to do with an out-of-align thrust line. Last night I checked it out and he was right,

Yesterday, before attending our third Nauticus run of the year, I replaced the angle-keeper in the boat, thinking maybe that was the source of the problem. And it was not. Yesterdays disastrous runs with the Type-23 was again with a boat that pitched down once the boat was in submerged trim and underway. Damn thing!

That's when my mentor, Gene Berger, came over to me, pitching (get it!) the thrust line issue: that I had incorrectly mounted the propeller shaft bearing foundation piece into the stern. And last nights measurement of angular displacement proved him right -- the propeller thrust line was about three degrees negative to the boats longitudinal center line. That's not much of an angular displacement, but I'm clutching at straws at this stage. I'm fixing that this morning and will run in a local cess-pool (flood-control basin) this afternoon.

There are two people on this planet I don't question when they give me an asignment ... Gene is one of them.

[He Who Shall Not Be Named]

Try and duplicate the porpoise action on the workbench.
Raise and lower the end of the sub at the same rate of
motion you observed in the water test and see what
your leveler is doing with the control surfaces.

Did that first off. Looks like proper response to changes in pitch. But hard to tell unless in crystal clear pool water, and have not had access to that kind of water of late.

M

[Scott T]

Try and duplicate the porpoise action on the workbench.
Raise and lower the end of the sub at the same rate of
motion you observed in the water test and see what
your leveler is doing with the control surfaces.