Kilo WTC

[raalst]

This item documents my first self made wtc.

it fits in the Trumpeter Kilo (plastic) kit.

I choose to mount the motor in the wet because I
failed to create a working watertight solution for the motor
Whatever I tried, always too much friction.

Then I found a reliable supply of motors, which meant I
could replace a motor with a new one of same size & shape.
I strip car electric door locks. one lock costs about 10
euro's.

but first ]the pipe[/url].
the WTC is made of simple drain pipe. it is 6 cm diameter
and wall thickness is 1,5 mm.
For the cloggies ]the forward wtc cover[/url]. Since I obtained a lathe
I tried my luck at turning a cover from brass.
It turned out that the pipe diameter varies. this cap only
fits at one end.

Next, the aft wtc cover.
The first model was made of brass, and made the wtc sink.
Next try was a cap of PVC. I bought a solid bar of PVC.
very expensive, but it will last quite a while.
I sawed off a slab of about 2 cm thickness. I turned
the disk down and made a groove for the O-ring and
presto. I am convinced you can do this with a mounted
electric drill as well.
in the aft cap, there are 2 holes for push rods
(sold by Norbert Brueggen at 3 euro's a piece), two
(stainless steel) M3 bolts which carry current to the motor
and one M3 bolt with an o-ring underneath it's head.
This bolt is the on/off switch. when screwed in the o-ring
seals off and inside the WTC two strips of steel (like in a
relay) are pushed together, enabling current to flow.
this relay-like switch was salvaged from an old video
recorder.

The pushrods are hollow 3-mm dia brass piping.
the inside end is soldered shut, so the outside end can be
used to shove in the plane pushwires (1.5 mm brass rod).
They are fixed with the ring thingy shown in the
photo. The other parts make up Norbert's pushrod seal

[raalst]

Part II

Inside of the

Part II

Inside of the aft cap
Here you can see the switch mechanism in detail, as well
as the bolts carrying the current.
I choose to connect the equipment tray to the aft cap with
velcro. lucky me, because the boat listed heavily.
I expect some twisting the tray will solve that.

my receiver
is an old multiplex pico with max 5 channels. I need three
in this dynamic diver.

the servo's
are mounted closest to the front of the WTC to minimize
the wiggling caused by the servo's.
I choose to mount them upright. This is good for keeling the
weight close to the bottom of the WTC, but the bent
pushrods require more room than I anticipated.

My batteries
are standard AA type (6x1,2 volts).
I wrecked a toy car to salvage the springs and made my own
battery container from plywood. The batteries really
determine how low the center of gravity will be in the wtc.



Edited By raalst on 1094888579

[novagator]

Look'n good, which Kilo kit?

Look'n good, which Kilo kit? The Revell one?

[raalst]

part III

the underside of

part III

the underside of the servo's
since the equipment tray is a sheet of flimsy plastic,
the servo's are fixed using a bit of balsa.

the
speedcontroller is also a light, small one for
up to 2 Amps of current. more than enough for the motor.
it also provides BEC.
the black things are connectors. the whole wtc can be
taken apart.

the motor
is mounted in the wet, simplifying things a lot and
providing more space in the WTC.
it is mounted using a motor mount from that old video
recorder again. This bit of plastic is jammed in a piece
of U-shape aluminium. This is glued to the boat bij
epoxy glue
The motor mount and the alu is fixed together with a
m3 bolt.
just aft of the motor is a rubber coupling.
another view

the linkages are brass rod.
note I made the whole dive plane swivel, not just the
little flaps of the kit. That made a more sturdy construction.
the prop axle is 4mm "silversteel", a reasonably rust-free
metal which is still soft enough to process in a lathe.
I made a M3 thread on the end, to fix the prop on.
I also used a sintered brass bushing glued into the hull
just forward of the prop, to prevent the plastic wearing out.
The prop
is a 5-blade raboesch with a dia of of 2
centimeters. (For the cloggies ]stengthened the bow[/url] with epoxy and glassfiber
choppings. I glassed in a ring to be able to tie
top and bottom hull together.

I had a lot of difference in the width of the underside
and the deck. might have been caused when glueing
together the lower hull halves.
Therefore I glued a thin sheet to the
underside to force the upper and lower hull to align.
The hook is used to fix rubber bands on to tie the upper
and lower nose together. Maybe in the future I will
replace the forward WTC cap with a PVC one. I can then
screw the hull parts tight to the wtc. Just like what I did with the aft wtc cover
for now, it works with the rubber band.
the upper bit of the nose

any requests for further details welcome.

tomorrow is the last day that the community pool is
opened, and I am allowed to take her for a spin there.
I am now busy weighing out the kilo (it's aft is too heavy)

Ps ]http://www.subcommittee.com/forum/icon_wink.gif[/img]

[bigdave]

Hi Ronald, Great work so

Hi Ronald, Great work so far. It is very challenging to get all those parts to fit in the small hulls. Even more so to get them trimmed right. It took along time to get mine ballasted. But it works quite well now. There are a few photos of my WTC and sub on my home page. Good luck on your project, Dave.

[raalst]

I was allowed to test

I was allowed to test drive in our community pool today.
And I probably get to use that pool more often !
let's just hope it resists county cutbacks...

Dave,

I have a general question ]Some of the tools of the trade[/url]
I took a picture of the epoxy glue I use, the central car door
lock device I strip and the lubricant I use.
All are available in Holland, dunno about elsewhere

The babe in the pool (and she's naked !-)



Edited By raalst on 1095024150

[bigdave]

Hi Ronald, The problem with

Hi Ronald, The problem with the Kilo kit is you do not have a lot a room for ballast or floatation. My WTC takes up most of the inside area of the hull, so I had to be creative. I used the Depron foam to ballast my Kilo. It is the type that most of the Park flyer planes are made of. It normally comes in 1/8-inch thick sheets. I glued strips of this along the insides of the hull. Having the foam on the sides also tends to keep it from tipping as much. For the ballast I took the stick on lead weights and flattened and formed them to fit the curve in the hull bottom. I then used RTV to glue them in once I determined were they would go, and how much was required.
My Kilo does have ballast tank, I use the RCABS system. I do still have a listing problem if I use a lot of power but it is not bad. It will straighten out once it is up to speed. I added more lead than I needed to lower the CG and added more foam along the sides to help the listing problem. I was not able to get the boat up to scale water line as my ballast tank is too small (I went as large as I could). But I feel it operates better lower in the water (turning and listing). It’s a trade off, I would rather have if dive and surface well, than have a scale waterline.
I am not using an APC now, but have made space available for an APC4. I will install the APC4 next year.
I made the bow planes removable but not functional. I plug them in for display, and pop them out when in the water. It did not need them; the rear planes work quite well. I did extend the rudder a little with some clear plastic. It was not bad but I like the turning radius better know.
Skip Asay was asking me at the regatta how it turned with just the bottom rudder. I showed him it would do less than 1-meter circles under water.
I hold the two half’s of the hull together with two screws that go into threaded holes in the WTC end caps. I made my sail removable to access the front screw. I used strips of Plastruct plastic to make indexing strips so the hull half’s would mate up correctly.
All in all I am quite happy with the way it turned out. It is not perfect but it is a lot of fun, and makes a great pool toy. It was not cheap though; the Kit is a drop in the bucket compared to the cost of the microelectronics that I needed to make it operational. It always seems once you go smaller, the cost goes up.
Feel free to ask any more questions. Dave.
I also added a few more Kilo WTC photos to my Homepage.



Edited By Bigdave on 1095027977