DIY Network

Giant-Scale Hydro Racers: Driveshaft Installation From "Radio Control Hobbies" episode RCH-206

Figure A

In this segment, Chris Chianelli gets some expert advice from Tony Castronovo on the installation of the driveshaft tube (figure A) in a radio-controlled giant-scale hydroplane racing boat. The driveshaft tube is what houses the flexible driveshaft that has a teflon lining material. The tube also serves to hold the front of the motor secure.


Materials:

Enforcer Stingray hydroplane kit
3/4-ounce fiberglass mat
All-purpose resin
Acetone
Talc powder
Modeling clay
Scissors
Adjustable wrench
1-inch paintbrush
Stirring sticks
Mixing platform or surface
Plastic containers
Paper towels
Newspaper
Rubber gloves

advertisement

Important: This demonstration provides some of the basic information for assembly and operation of this particular model racing-boat. There are variations in assembly for each particular model or kit. Read and carefully follow the manufacturer's instructions that come with yours, whether it is this particular model or another. Additional information about assembly as well as running, troubleshooting and fine-tuning the model can be found in the manufacturer's instructions.

Installing the Driveshaft Tube

• The installation of the driveshaft tube itself is fairly straightforward. It is the follow-up steps involving working with resin and fiberglass that require some special preparation, materials and techniques. Fiberglass covering must be installed over the tube to protect it during the jarring that can occur during high-speed racing. According to guest expert Tony Castronovo, once the resins and chemicals are mixed for use with the fiberglass, you are typically limited to a 10- to 15-minute working time. With this narrow window of opportunity, advance preparation and organization are the keys to success.

• To attach the driveshaft in this boat, slide the tube through the pre-drilled hole in the body and position the tube with the front end at the rear of the engine transom (figure B). Connect the tube to the rear of the engine, and use an adjustable wrench to secure it with the provided mounting nut (figure C). Avoid over-tightening the nut.

  Figure B

  Figure C

  
  

  	Figure D
  	Figure E
  	Figure F
  	Figure G
  	Figure H
  	Figure I

• Next, you'll need to measure the shaft and make a mark about 5 inches behind the rear of the engine (figure D), and another mark about 5 inches behind that. These marks will serve as a guide for cutting the fiberglass material that will be used to protect the shaft tube.

Working with Fiberglass, Part One

• Use household scissors to cut your fiberglass mesh to proper size, using your marks as a guide for the length of the sections. We used 3/4-ounce fiberglass mat for this installation. Once the chemicals and resins are applied, the fiberglass will conform to the shape of the boat-hull much better than cloth or other materials would.

• Once you've cut your mats, place the first one between the boat stringers as shown (figure E) to form the first layer of fiberglass.

• Tip: In order to prevent resin from leaking out of the driveshaft opening at the back of the boat, lift the rear of the boat and place a small amount of modeling clay around the back of the shaft tube (figure F). Mask off areas along the top of the boat body using newspaper and masking tape to protect the exterior finish from any drips or spills.

• With the shaft tube in place and the fiberglass mats cut, you are now ready to mix the resin and chemicals that you'll use for bonding the fiberglass to the inside of the boat hull.

  Safety Alert: Wear eye-protection, protective gloves when working with these chemicals and work in a well-ventilated area.

• Using graduated measuring cups and a plastic mixing container, measure out one ounce of resin and pour it into the mixing container (figure G).

• Pour in one ounce of talc powder, and mix the ingredients with a stirring stick to form a paste. The talc helps to thicken the mixture and aids its ability to fill in gaps.

• Once the mixture is well blended, carefully add 8 to 10 drops of MEK (methyl ethyl ketone) to catalyze the mixture (figure H). The ratio for adding MEK is 8 to 10 drops per ounce of resin. Since we added talc as filler, we added the maximum of 10 drops to compensate for the extra material.

  Important: The catalyzing chemical reaction actually produces heat, which is instrumental in the bonding process. Add only the proper amount of MEK. Adding too much MEK can cause the reaction to over-catalyze -- producing excessive amounts of heat and potentially damaging the boat.

  Tip: It's better to make up more of the resin mixture than you will need (then just discard any extra afterwards) than to err on the side of too little, then have spend extra time mixing up more during this time-limited procedure.

• Use this mixture to apply the first coat around the driveshaft tube using a stirring stick or wooden applicator (figure I).

In the segment that follows, Chris and Tony continue working with fiberglass and resin to complete the driveshaft-tube installation.

Chris Chianelli's Mailbag

Q: Larry K, a DIY viewer from Raleigh, NC writes: Chris, I'm thinking about getting into [RC] boats. What's the best power source?

A: There is no "best" power source for all circumstances. Each of the commonly available options has its place in the RC hobby -- whether electric, Nitro, gas ignition, etc. Electric racing boats, for example, are ideal for a location where noise is an issue. Electric motors are both fast and quiet. Gas-powered engines that use a spark-plug ignition and run on a gas/oil mixture are a long-time favorite. The power source you choose is essentially a matter of personal preference.