1/96 Thor Permit

[thor]

That linkage system is a mess, Mike! Yikes!!!

I think you have received some excellent advice above. You should be getting at least 45 degrees of travel is not a bit more. That boat turns within its own length if trimmed and set up properly.

[JWLaRue]

Mike,

We really need to get you linked up with Jim and me. (I'm the one in the Annapolis area) I am certain we can get you going fairly quickly.

-Jeff

[Parallax]

Hi all, time for an update,
I disconnected the linkages from the collars. This made the planes partially free, buy I found the starboard plane still had bind in it. This was caused by the trailing edge of the plane coming in contact with the fixed portion of the plane. I then realized that the rod had become slightly bent and after a small amount of work it is in a much better place. Matt, you were absolutely right about how much travel the rudder has.

The clips on the linkages pretty much fell apart, and I think I will make all new linkages as the are also in pretty bad shape. Once everything else is disassembled I am going to need to figure out how to connect the portside collar and linkage so it is not making contact with the rudder yoke.

To Subculture - I cleaned the collars off with a dremmel and brush as best I could and sprayed it with penetrating oil. If that does not work I am wondering if it is safe to drop the aft of the sub into the sodium carbonate solution in order to free up the grub screws?

Assuming I can get them off I need to get replacement collars. I have to figure out the size as well as a place to get stainless steel grub screws.

Jeff- Jim actually sent me the information for the meetup on December 10th and I will be coming with the Permit, whether its working or not. If you are going, look forward to meeting you there, but if not I would be happy to head up to Annapolis if you could spare some time.


.

[JWLaRue]

Mike,

I will be there on the 10th....will make sure we have some time to look at your Permit and see what we can do to get it running.

-Jeff

[Guest]

To Subculture - I cleaned the collars off with a dremmel and brush as best I could and sprayed it with penetrating oil. If that does not work I am wondering if it is safe to drop the aft of the sub into the sodium carbonate solution in order to free up the grub screws?

Assuming I can get them off I need to get replacement collars. I have to figure out the size as well as a place to get stainless steel grub screws.

The electrolysis method won't affect the hull, but you do get a rusty scum on the solution's surface which may stain the finish on the hull if it isn't sealed well, so I would use that as a last resort.

I expect the collars use imperial threaded screws, not sure which size- I use metric as they're much cheaper and easier to source here in the UK.

[salmon]

To help narrow the choices, the grub screws are probably 4-40 or 2-56 if imperial.

[Foxtrot Oscar]

To echo what Thor said, this boat handles like a fish. It's worth the effort to get the linkages set just right.

[JWLaRue]

Mike,

I will try to remember to bring a number stainless steel set/grub screws in different sizes with me on the 10th....

-Jeff

[subdude]

I'll try to remember to bring a few as well. And Mike, the collars are most likely 1/8".

Jim

[Parallax]

Permit update time!
Firstly Dad and I had a great time at the SubComEast meet in Shrewsbury. Seeing the different models and talking with everyone was great. Jim thank you again for the set screws.

Before I went to the meet I made some modifications to the Permit. The number one problem was the lack of a snorkel I could fit in the sail. In order to make the ballast system work, I had to rig a snorkel up. Feel free to laugh. That said it did function as hoped, if not to look or scale.



I cleaned the collars as best I could and tried penetrating oil but had no luck getting the set screws out. I plan on trying the electrolytic approach this month, but did not have enough time before the meet. I rigged up new brass linkages to operate the planes and rudder. I originally wanted to keep it as simple as possible by using z bends but there was not enough space to slide them into the collars.


Cleavis style pins like the ones already in it were to large as could be seen by all the binding. My solution was to take a page out of the RC airplane book. I put a small 90 degree bend at the end of the 1/16 linkage, and then soldered an even thinner piece of brass parallel to the linkage across the bend. With this I was able to lock the linkage to the collar without having any bind. Its probably easier to watch this video to see what I mean: https://www.youtube.com/watch?v=3zlXiIOzS7s



Best news is the range problem is fixed now and steering and diver controls all work I did have several issues. The first is that I still do not have submerged buoyancy set correctly. As it starts flooding, the sub begins to settle aft first. Once the tank is fully flooded it sinks right to the bottom. I though I had that worked out in tub tests to keep it right at the surface, but wrong!



The second big issue is the emergency blow. I still need to properly set up the throw. I kept accidentally pushing the blow all the way over, using up the gas even when I was using the snorkel. So no gas available when I needed it. I believe this led to the next problem with minor flooding in the WTC. With the sub on the bottom, I could not get it to drive off the floor. The ballast system was able to bring it up by using the available air inside the WTC. However I believe that caused water to be drawn through some of the seals (not sure which ones) due to the vacuum.
So in short I need to get the emergency blow sorted out before the next meetup. Also... How do you know when the cylinder is full of gas?

Last questions. I would like to use a tap and die on the linkage magnets. Does anyone know what size die you would use on 1/16 rod and what size tap for the female end of the magnet?

[Parallax]

Yay Leaks!

Hi guys lookign for some advice/suggestions as usual.
On Sunday we took the Permit out to SubComEast meet. We had a great time but we ran into a flooding problem. We set the buoyancy so the top of the sail was just out of the water with the ballast flooded. About half way through the meet, we lost control of the sub with no response to any controls. The Permit came to a rest in about 4 feet of water.

After being rescued, I found that the forward compartment in the WTC had filled about 1/3rd of the way up with water. This in turn had fried our radio controlled power switch, shutting down all electronics in the sub. There was moister in the aft compartment but no significant flooding. The good news is after bypassing the switch, we found all the rest of the electronics were still working (Big Relief).

I did a test on the WTC and at first could not find anything. Then I discovered that at certain angles, the front cap seal well start leaking a small but steady drip. I inspected the O-ring but it seemed fine, and had been coated with silicone grease. There were two things that stood out to me. When I ran my finger around the inside edges of the WTC it was not perfectly round as I could feel smell dips. I also noticed at one point on the cap there is what appeared to be some kind of casting tab or flashing that had been sanded down, but is not flush with the edge of the cap. I could not make out where exactly the air and water was escaping past the O-ring. I tried rotating the cap around but did not seem to have and noticeable difference

I'm wondering if I can used a slightly thicker O-ring on the cap to make up for the small amount of waviness in the WTC? Should I try to sand the WTC inside edge to smooth out the waviness? Would a very small ridge on the cap be enough to prevent the O-ring from sealing (less then a mm)? Are there are other seal options that can replace an O-ring?
Thanks,
Mike

[salmon]

When your end cap is on, do you see an even seal by the o-ring? (You should be able to see a darker contact line where the o-ring is smushed against the tube)

If you do but it barely has contact, take the o-ring off the end cap, wrap Teflon tape (used on pipes) anywhere from 3-6 times around the channel. Inspect your o-ring for damage like nicks and tears. If it looks good, relube it, install and test. Inspect the o-ring on the ballast tank bulkhead too!

[JWLaRue]

Mike,

I would not sand the inner surface of the WTC cylinder at this point. I would start with what Tom (Salmon) suggested. These cylinder tubes are made by extrusion so there will be some variation on that inner surface....but typically not a major problem.

Where on the endcap is the 'ridge' that you mentioned? I'm going to assume it's not in the o-ring channel, but rather on the body of the endcap that fits inside the cylinder? If correct, then go ahead and get rid if it....just in case. What is important is that o-ring contact seal that Tom mentioned.

-Jeff

p.s. your boat ran well on Sunday. I think that extra time spent fine tuning the trim really helped.

[salmon]

Just to add some visual (I am a visual person) here are some photos:

Tools I used are silicon, teflon tape, Xacto, and tooth pick to clear out channel and apply some silicon in channel before putting on tape (not necessary).


Pinch O-ring and it is easier than trying to dig it out and possibly damage it.


You should see a strong band of contact when done. You can see the front one may have too much, but that happened because the rear one was much less contact. I was told by Dave Manly, that he fixed his channels with clear waterproof epoxy and allowed it to evenly coat the channel. I have not done that yet, but may in the future to test.

I echo what Jeff said about not sanding the interior of the tube. Sanding the flash is a good idea.

Peace,
Tom

[sam reichart]

A nice followup with photos, Tom. Something I'll check with my new cylinder as well.