Aquacraft twin outboard

[greenman407]

I have made a great deal of progress on this boat. Both engines are mounted and the steering linkage is in place. I tried to use a Sombra labs reciever in it with an Aristocraft pistol grip radio. The two are not compatible. Since I like to drive these fast boats using a pistol grip radio, I made the decision to use my new 2.4 GHZ. Spectrum radio. Ill just need to buy a reciever for it as I used the one that came with it to control my 1/8 scale gas car. Also installed is the throttle cables. My next step is to build a boat stand and do some painting on the fuselage. Oh yes, must not forget to hook up the fuel tanks. Pictures soon.

[greenman407]

It is time. Youll see here a factory made steel throttle cable holder. Then a home made brass version. Then you will note the steering linkage attached to the starboard engine and the multiple designs of inter connecting linkages between the two engines.

[greenman407]

[greenman407]

In these shots you can see that the throttle cable hookup is with limited space. Therefore I had to cut down and drill out a threaded connector to get it small enough to fit in the available space. Also, to get the throttles to work together the cables had to be attached at the same point on the servo. In the last view I will be experimenting with different props at the same time. More on that later.

[greenman407]

Throttle cables hooked up and synchronized. I then started to build the Boat stand which holds it while you transport and start it up at the lake. Now its time to get some clear paint on the boat stand to protect it a little bit and coat the inside of the fuel tank area with some brushed on 30 min. epoxy to help protect the cheap white styrofoam that is exposed.

[greenman407]

A quick update on progress. The 2.4 GHZ radio is shown here along with its reciever. For marine use however its recommended to use the Marine version with two antennas. One antenna should run vertically in a tube and the other one should run horizontally. This because of the fact that 2.4 GHZ signals tend to deflect off the surface of the water. I didnt want to take any chances.

[greenman407]

Just a note on "binding" these recievers. On the Sombra and Polk recievers ,binding is instant. On these I have found that it can be a problem. Saturday night I wasted an hour trying to get this thing to bind.......but, to no avail. I worried about it all day Sunday and then first thing Monday morning before 7 AM I turned it on and "Wallah" It "Binded"!!! Also, on all other radio systems that I know of they tell you to turn on the transmitter first and then the reciever. On these, they tell you to turn on the reciever first and then the transmitter. Whodathunkit??!!!

[greenman407]

Todays progress. I installed the fuel tanks on the freshly "poured" epoxy floor. Then using glow fuel hose , I routed all the fuel line and hooked them to the right places. Im using check valves in the fuel pressure hoses to make sure of constant pressure at the carburators. Tommorrow, I will wrap the reciever in a ballon and then in bubble wrap And rout the two antennas. That should pretty much take care of it except for painting and adjusting the center of gravity. This boat is going to be tail heavy so I will probably have to add some weight to the nose. Hope not but we will see. Then, ofcourse, comes the testing phase and trimming. Since I live over 50 miles from my medium sized boat pond I cant go all the time. The police have been called on me twice by a well meaning , law abiding, tax paying, holier than thou, citizen. Did I mention well meaning. Therefore I try not to stay for longer than an hour. Some of the neighbors like it . As for others............ The first cop that came out told me not to worry about it. I dont know about the second cop who was dispatched on another outing. I was driving away as he pulled up. What timing! Stay tuned race boat fans. This Epic adventure continues!

[greenman407]

I have other places that I can go to ,to be sure. But we all have our favorites.

[greenman407]

Ok , here we go with the Fuel tank hook up and radio install.

[greenman407]

Heres a shot of the back of the boat stand where I made a support for the engines to help keep the torque of starting the motors from putting too much pressure on the steering servo.

[greenman407]

UPDATE: The exhaust check valves are not going to work. Once the engine starts the buildup of exhaust over pressure floods out the engine. Also it will be necessary to put a hemostat or clamp on the fuel hose of the engine that you are not starting. If you dont it will flood while the other engine is running. This because you dont have seperate fuel tanks for each engine and the exhaust pressure from both engines is feeding into one tank. So after the first engine is running you pull the clamp off the hose to the second engine right before you try starting it.

[greenman407]

Also the plumbing of the fuel tanks is critical. On the lower tank the brass tubes that go in the tank must be configured in this manner. You need three tubes. The one that feeds the upper tank goes in and draws directly off the bottom. The other two are for exhaust pressure. They must go in and be curved upward toward the top of the fuel tank to exert a downward force on the fuel in the tank. If they are not at the top then fuel can siphon out thru the exhaust when you are not aware.They must be hooked up to the engine exhaust pressure taps. Without them your fuel feed will be erratic and you will spend all your time fighting with it. The upper tank is fed from the bottom tank. So you need three tubes here as well. One tube feeds from the bottom tank and MUST go in and be bent to go up to the top of the tank. If not then the tank will never fill up. The other two are for the carburator feeds. They must feed off the bottom. If you set it up this way you will have no problems if you keep them as close to the engines as possible and as high as possible.

[greenman407]

OK!!! Today both engines started up and ran. I said that in a way that sounded like.......NO PROBLEM. Actually , neither one of them would start......initially. Remember, both of these engines were purchased, well used on EBAY. So, I pulled both carburators and removed the needle valve assm. and sprayed Blaster thru them to clean them out, along with the fuel nipples, making sure that spray also came out of the barrel vent. Also, I used my hobby engine compression gauge. It showed compression in excess of 60 lbs. Thats about average. Once reassembled with new glow plugs and some patience they both started up. I have two hand held starters for these engines. One is a new "Hobbico" high torque starter. It appears to turn at a slower speed than my other one. The other one is a "Sullivan". One engine that didnt want to start on the slower speed "Hobbico" , started up instantly on the higher speed "Sullivan".

[greenman407]

Next step is to balance the boat. Outbourd tunnel boats work best when the balance point is at 27% from the rear. So multiplying .27 x hull length(28") gives me 7&9/16" from the rear of the sponsons. Ill be adding lead weight inside the front of the radio box to acheive this. Next I want to get some paint on the Fuselage. STAY TUNED DUDES!