BBY Micro Turbine Hydro for SSSH

[Dr. Jet]

As the founding member of the Santee Lakes Old Boater’s Society (the SLOBS), and “President for Life” (a.k.a. der Führer), I am always trying to promote our unique brand of FE racing. The boating area at Santee lakes is limited by several steel-reinforced concrete bridge piers and a three-ton rock in the middle of the pond. LSH boats can run in our pond, but they spend a lot of time turning real tight corners. Super-fast N-2 boats run out of room REAL fast at our pond. P-sized and larger hulls are out of the question. The bridge and rock do not move when hit by boats. I know this for a fact from watching other people try.

Our motto at Santee Lakes is “Fast, Cheap, and Out of Control”, but how can you do FAST in such a small area? As many of you may know from the “Red” forum, I have been focusing on a spec class called Santee Sport Scale Hydro or SSSH for short. I have decided to post a build thread on this forum to expose more people to the concept of CHEAP racing.

SSSH, like LSH, specifies a particular hull, motor, and battery combination. SSSH hulls have a 400 mm (15.7”) maximum length and must resemble a “real” hull (no outriggers). Plastic propellers (cheap) are required, and can be modified if desired. The SSSH “Spec” motor is a cheap 3000 rpm/V brushless outrunner that can be purchased on ebay for under $26 delivered, and that price includes a 30A ESC. It doesn’t get much cheaper than that. For batteries, 2S LiPo, or 6 round cells of 1000 to 1950 mah are the accepted cells. I have seen 1500 mah 2S packs at UH for around $10 to $12. This motor/prop combo draws about 10 to 12 amps so runtimes will be 6 to 12 minutes, depending on your setup and the current draw will be well below 15C for just about any setup. You don’t need high-discharge cells to race SSSH. This motor/battery combo has enough power to blow these little hulls off the water if your set-up is not right, so I would say that they qualify as “Fast” enough. SSSH racing specifies 4-minute heats on a 2-buoy course, sized to your particular pond.

This build will be a Micro Turbine Hydro (MTH) from Blew By You Racing. At $30 for the hull, this kit fits perfectly into the philosophy of “Cheap” racing. I should be able to have this boat ready to race with receiver, servo, and battery for under $200. Using parts and radio bits I have lying around the shop, it is possible to cut that dollar figure nearly in half. I plan to laser-cut the internal wood frame, similar to the wood frame in the Campbell Classic Hydro kit. This is “prototype” work; therefore, I will not include the laser-cutting costs in my total, since this could be just as easily done by hand with a saw and some sandpaper. I’m going to do it that way because I’m lazy and I may have need for additional wood bits in the future. If it works out, I may make the CAD files available to Randy at BBY for his use.

For this build, I will be using a 2 mm stainless steel driveshaft (no flex or wire drive), a 2.3 mm x 2.0 mm motor coupler, a micro brass rudder, and Graupner K29 propellers from MHZ. These props are cheap, ready-to-run, and require no balancing/sharpening. While the rudder is not super-cheap, it is cheap enough when compared to Fuller, Solinger, Speedmaster, and similar CNC-cut aluminum rudder assemblies. Furthermore, ordering all your bits and pieces from one supplier reduces shipping costs by spreading them around several parts. The flanged 2 mm x 5 mm ball bearings are available from Boca Bearings at a nominal cost. The stuffing tube is a carbon fiber tube that I got from a kite supply store (I have a lot of these in my shop). The I.D. of these tubes is a bit less than 5 mm, but some careful sandpaper work should easily re-size the I.D. to fit the bearings. In order to “keep it simple” and cost-effective, I will limit the use of carbon fiber to just the stuffing tube, and possibly the turn fin. All other materials will be of “conventional” construction to make it easy for everybody to duplicate this build if desired.

I’ll post some photos of the current parts inventory later tonight when I get home.