AEROTECH 60 OUTBOARD TUNNEL

[greenman407]

I picked this up off of EBAY a month or so back. Aerotech, Aeromarine, Leecraft, and others are all out of business. So, if you want a nitro powered boat, pickings are slim. I jumped at the oppurtunity. This one will be powered by a NovaRossi/K&B Hybrid engine with a tuned pipe. More on that later.

[greenman407]

So I got this new engine and am prepping the hull and lower unit. In the pictures you will see the .46 outboard upper unit and also the header and tuned pipe. In order to install it Ill have to cut out a section of the lower unit. Here I have marked it and Monday morning, at work, I will use their table band saw to carve it out. Also I have here installed the anti-cavitation plate extension.

[greenman407]

So here we go with some progress. After some further review I determined the need to remove more aluminum from the lower unit. Like so. The manufacturers sales rep. has provided me with the suggested pipe ,header length. So tomorrow Ill be cutting that down and smoothing out some rough edges. Also Ive got an idea in hand as to how to support the pipe. More tomorrow.

[greenman407]

Ive got the Header pipe cut to length and the mount for it made. I used a hydraulic tube mount. It had a circular cutout that I expanded on and then "Smooshed in some Grey RTV silicine down into the grooves and I put in too much on purpose. That way , after it hardens I can carve out a proper sized circular shape in that material to match the diameter of the tuned pipe. Because the pipe is Carbon fiber, I consider it fragile and in need of good cussiony support. I also modified the water cooling setup. Pictures soon.

[greenman407]

So the engine is all done and mounted and Im hooking up all the cables and such. Yep.........I owe you some pictures. Im using silver solder on the steering cables and throttle cable as well as the mixture control. Thats because we dont want any stress or engine vibrations to ruin our day.

[greenman407]

OK here we go with the pictures. Im going to start it up tomorrow.

[greenman407]

Notice the prop, how funny it looks. Very different from the norm.

[greenman407]

Then we have the radio box. You can see the three servos. One for steering, one for the throttle, and one for adjusting the fuel air mixture while you are driving it. Im using a 2000mah Lipo to power the electronics. The radio is a 2.4ghz Spektrum Mr3000. The receiver is wrapped in bubble wrap and sealed up in a baloon to protect against possible water intrusion.

[greenman407]

The sales rep for Novarossi US tells me that He suggests that I use a Heat gun to heat up the engine when starting for the first time. From what I can gather this is to expand the cylinders shape somewhat. These engines do not have piston rings. They rely solely on piston shape which is slightly tapered to match the taper of the cylinder. When you get a brand new engine and you turn it over by hand , you can feel it get real tight at the top of the stroke. That is what you are trying to break in, that point of seal. Since the piston is made of aluminum and the cylinder is made of brass with a chrome internal layer, the expansion of the different materials are not the same. Because of the coefficient of expansion of these different metals, the compression of the engine will be higher as the engine warms up. Thats why it so important to have the engine properly broken in.
I know, I know..........it sounds like a bunch of gobbledegoop right? Well there is a measure of truth in it.

[greenman407]

And run she did. It started right up. I pretty much ran out the fuel tank in the boat. A neighbor lady came over to the fence and was wondering what that weird noise was. When I told her she just smiled and walked away, as if to say,"Here we have a 55 year old man and whats he doin on Thanksgiving? Playing with toys better suited to 20 yr. olds. Well........I may reside in the body of a 55 year old but My heart is still 15.

[greenman407]

Prepare for after action report. Test run tomorrow.

[greenman407]

The first boat of the three into the water was this boat. Since this is a brand new motor, it requires a break in period. I started at 3 turns out needle valve setting for the first run. I had plenty of smoke out the exhaust . That plus the way it was running and sounding, I new it was still rich, which is what we want for a little while. For the second run I leaned it out a little bit down to 2&3/4. For the third run I dropped it down to 2&1/2. I could still see some good smoke , so on our next outting we will go with a little bit smaller prop for the first run and go from there. Pictures shortly

[greenman407]

ive already entered a whole bunch of stuff already

[greenman407]

Heres a video taken Friday as well.https://youtu.be/BqkmsZs2nDk

[greenman407]

I decided to make a set-up board. Its a heavy straight plank that you use as a guide to establish proper height of the propeller to hull. If anyone on this Forum has any experience with operating a full size pleasure boat, they know that the propeller depth is far below the water level. Model race boats are setup to use surface piercing propellers and running hardware. That simply means that at least some of the propeller is above the water when the boat is on plane. The height of that prop out of the water is directly related to how much performance you can eek out of it. In this case I decided to raise the prop substantially. Instead of the more conservative setup that I have been using, I raised the engine and therefore the propeller about 3/8".
This will allow the engine to turn up more RPMs, and therefore we should see a substantial increase in performance. In the pictures you will see the surface of the board and where the prop is in relation to it. The top surface of the board is the height of the bottom of the sponsons or riding surface. This is not the surface of the water because even at speed the sponson edges are riding down below the waters surface. The amount varies with boat weight and sponson design, but it does gives us a reference point to setup with.