Saturday, May 16, 2009

Building the VS1 part II

I built my VS1 tunnel ready today... First I checked all the joints in the hull where the different plywood parts join and added some CA glue where it was needed.

Then (as per instructions) I blue-printed the bottom of the sponsons with a flat Great Planes sander. The idea is to match the left sponson with the right so when you put the boat on a flat set-up surface there will be no "tweak". Then also to make the rear riding surfaces completely flat... Do it with 80 grip paper first and finish it with 150. If you sand through the clear coat you need to re-seal the wood. Use an automotive 2K clear or epoxy finishing resin (like ZAP). If you use the finishing resin brush it on and leave if soaking in for a while and then wipe most of it off with a lint-free paper towel. After the clear or resin has hardened over night re-sand it slightly with 150 sanding paper again...

One big advantage with the O.S. motor is that you can adjust/shim the steering pivot pin angle to what you want it to be at separately from the AoA of the prop. If you look at the first picture here above (upside down) you see that I first attached just the motor mount base to the VS1. Its much easier to check the hinge pin angle then vs the flat set-up board when the rest of the motor is not in the way... Shim it so its at least at 90 deg to the "water" to begin with. I'm no tunnel expert so I'll come back with some more set-up guides as I figure it out...

Then I assembled the rest of the lower end of the motor to the rig and set the AoA of it with a digital angle finder on top of the spray plate. The hight of it I set at so the round "bullet" is just above the set-up board.

Its also a little easier to make the steering cable assembly without the engine in place also. I opted for using Sullivan #508 wires. There is nothing wrong with the stock wires but I just like the Sullivan's better...

I use Futaba S3305 for steering and Futaba S3115 for throttle.

The stock VS1 steering pull-pull wheel is used. its made for the stock Futaba 35 mm servo disc. In this picture you can see that I also used the extremely flexible Sullivan #507 cable for the throttle - its only 0.8 mm in diameter and the drawback of that is that the outer nylon tube is tiny also. But I used the stock VS1 nylon tube as a step-up adapter by using a 2 mm drill-bit and opened the hole slightly so it could be pushed over the Sullivan tube... A drop of Zap green CA glue at each end and it's done... :)

You can also see that I opened up the holes for the Sullivan #508 nylon tubes in the plastic guide so I could run them through it... I CA glued them to the plastic guide plate.

Ps. don't forget to add some silicone sealant or Zap-a-dap-a-goo between the plastic guide and the box before you mount it to the box...

The other end of the tiny Sullivan throttle cable also got the same step-up stock VS1 nylon tube "adapter" over the tiny Sullivan 1.8 mm nylon tube as I did at the radio box. But this one is so short you can get away with not opening up the hole at all in the white stock tube. Its a tight fit though. A drop of CA glue between the nylon tubes and they cant slip-n-slide...

I made my own metal tank with a hopper for the VS1. I will test if its any noticeable difference vs the stock tank (that is a really nice unit BTW).

I balanced it at 219 mm with two packs of Great Planes GPMQ4485 self adhesive lead weights. This is where the bulk of it is placed and then the rest is inside the radio box floor.

A front view of the tank.

I made a very simple oiler for the motor. It's made from a simple 2 mm thick fiber glass sheet with two holes where I bolted an 1/8 off-road fuel filter holder to... Simple and clean. :)

One of few things we can modify on out motors (we only run the stock class) is to make the fins sharp. So I did. The other modification we can do to the motor is to re-shim it so I removed the shim completely for added torque.

This is how it looks with decals on it.

We have a fixed national starting number on our tunnels all season - mine is #5 this year...

So now its basically done - it's a few items to fix before testing but not much. This will be fun! :)

Ps. the RTR weight (no fuel) ended up at 2400 g.

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