Jeffs Type VII

[fwjeff]

Started construction mid Summer & finished around Sept 09.

[He Who Shall Not Be Named]

Nice work. Now, tell us about the problems you encountered employing the fittings kit and SubDriver. Points awarded for brutal honesty!

And what about the finish? What primer, paints and weathering mediums were used and the tools employed to lay the goop down.

Nice outdoor shots. God, I love a boat that floats at the designed waterline!

David,

[fwjeff]

Hi David,
Thanks! Getting the waterline right took about two weeks of experimenting but it was worth it. Most of the issues I put in the posts while I was building but a few that come to mind;

1) Shorted out the antenna lead & fried the speed control - added a tube to use the RX antenna

2) Air getting trapped forward of the air bottle - changed bottom bracket to lower the bottle & reduce the diameter of the rtv seal

3) Had a couple of prop shaft seals fail - just needed to replace them

4) The arms for the planes & rudder were not useable - made up brass replacements. I also used the wood decking, looks great but causes all kinds of problems with expansion, warping, and with trapping water in the deck slots.

Things I'd still like to do;

1) add gear reduction for drive
2) install Raboesch props (have them, just need to install them
3) Tighten up the restricter in the line from the air bottle.

Overall everything worked really good, once I got past the worst of the learning curve. Absolutely love the Snort & ADF. I usually don't use primers, just the light grey base. Paints are all Model Master Acrylics. Most are mixed, I'll usually pick a color & spray a base coat.

On the lighter color & pre shade using the dark grey on seams & some random spots. Then I'll mix a slightly lightened shade of the light grey & re-spray an incomplete coat to cover most of the preshading. This step gives some nice variation in the shade.

The dark grey & do the same but skip the pre shading. Next I add rust, this time I used Rustall & some rust acrylic paint. After this I do some weathering with pastels, just grind some off on a piece of sandpaper & apply with a brush.

Clear coating tones the pastels down quite a bit which helps with overdoing it, for this again I use Model Master Clear Flat, usually with some light grey added.

[tsenecal]

I agree with david, I am amazed that someone out in the world has a working r/c of this 1:72 sub that actually appears to float at the right waterline, and not decks awash. extremely good job on both mechanical and paint.

[Outrider]

There's a lot of interest in the Caswell/Merriman Type VII, but not as many build logs available as I'd like. You mentioned doing a build log... Do you have a link to it you'd be willing to share? Can you easily post your build log in the regular builder's section so we can preserve your experience?

A few questions, too.

1) Shorted out the antenna lead (where was the short?) & fried the speed control - added a tube (where?) to use the RX antenna

2) Air getting trapped forward of the air bottle - changed bottom bracket to lower the bottle & reduce the diameter of the rtv seal (Would drilling a hole have been a suitable alternative?)

3) Had a couple of prop shaft seals fail - just needed to replace them (Is the Wiz using cheap imported goods again?)

4) The arms for the planes & rudder were not useable - made up brass replacements. (Any more details on this?) I also used the wood decking, looks great but causes all kinds of problems with expansion, warping, and with trapping water in the deck slots. (Sounds like a good recommendation for a Photo Etch deck.)

5) Any comments on the SubDriver build up? Did you get a kit or a fully assembled SD?

6) Can you give some guidance as to weight and foam amounts and placement?

Thanks for contributing!

[fwjeff]

Hi,
I didn’t actually do a build log, not organized enough for that. I did take lots of pictures though. And always like answering questions! I’ll go through the questions above in order:

1) Antenna – When I did the initial radio setup I checked the nylon bushing installed over the bolt to be sure it was keeping the bolt isolated from the motor mount plate. It was, but I noticed the bushing was pretty short & a bit thin on one side. When I installed the antenna later I forgot to re check to be sure the bolt was properly insulated,,,,,,,, Now, the tube I installed. Look at the photos in the note above. The first picture in the fifth set is the motor/servo assembly. If you look close you can see the 1/8 brass tube passing alongside of the servos then curving in closer to center then going through the rear bulkhead. I just ran the radio’s original antenna through it & sealed both ends with RTV.

2) Air bottle – When I was doing my trim I kept having trouble with the balance changing when venting the ballast tank. What I found was if the sub was at all bow up when venting the tank or even level a fair amount of air was getting trapped forward of the air bottle. It didn’t look like much but it was enough to throw the submerged trim off & sometimes made submerging difficult. To fix it I pulled the bottle out & removed the RTV from the top. I then replaced the strap supporting the bottle with a new one that was bent to allow lowering the bottle about 1/8 of an inch. There is clearance between the bottom of the Driver & the hull to still fit. When I reinstalled I put just enough RTV to get a good seal around the neck of the bottle so most of the top of the bottle is not in contact with the plastic wall. Look at the third picture in the fifth set above.

3) Prop shaft seals – I had two develop slight leaks. I think there was a burr on the shafts but not sure if this caused it as I did quite a bit of pushing & pulling during the installation. The good thing is they are easy to replace, Dave recommended removing the entire seal holder from the bulkhead, which works really good. Make sure if you develop a leak, easy to see without removing the driver as the chamber fogs up if it’s taking in any water. If you, do remove the driver & attach a tube to it & pressurize it then dunk it in a tray of water to find the leak. Make sure to operate the servos & motors to check all situations.

4) Control Arms – I didn’t like the looks of the cast control arms & actually the one with the bolt thing I never really did figure out. I’m used to making brass arms for airplane models so I just did that. The arms are 1/16 brass soldered to the tubes the dive planes are mounted on. The size & shape isn’t critical as there are very low loads on them so I made them about ¼ wide at the base & 1/8 – 3/16 at the pushrod end. Add a set of holes along the length so you can adjust the control travels. I think both the bow & stern arms were about an inch long. Size them to allow maximum plan travel & you can then reduce from there by moving the pushrod closer to the pivot.

4) Decking – I really like the way the wood deck looks. It weathered nicely & just looks good! But, too many problems. First it swells & warps. The length of the deck changes about 3/32 in length when it’s wet. Also it cups so it needs supports running across in several places. The main thing I wanted though was having the holes open to let air/water to pass through the deck. Unfortunately at this size surface tension takes over & water will not pass through the slots. And the last issue is having wood above the waterline complicated the trimming process a bit. I think the photetch would be nice to try, it would need some support structure to stiffen it up & would still have some expansion issues but shouldn’t be as bad as the wood. Also being thinner might help the water get through the slots.

5) Subdriver – Mine was assembled so I had it easier. Probably a good idea as I had a known starting point. This was really helpful on a first project as there was so much to learn. Second time around I’d probably do a kit. Once you understand how everything works the assembly shouldn’t be too bad.

6) Ballast / Foam placement – I’ll take some measurements & make some sketches tonight!

[fwjeff]

Here are some sketches showing my ballast & foam placement. Keep in mind this boat has a wood deck & brass railings so it's weight & buoyancy are a bit different.