BBY Micro Turbine Hydro for SSSH

[smm_cbf]

well, there is a lake near me that is set up for rc boat racing, and iv seen people racing there before, but iv never gone up to them asking if they have offical races. i would lover to start a clone of what your doing , only in my area, but iv been getting kicked out of every lake lately. and im only a kid so i don't think i could make anything offical, only like fun get togethers...

[Dr. Jet]

The SLOBS are anything but organized. Generally, we "race" and the losers buy the winner lunch. That's about as sophisticated as it gets. The SLOBS have almost no rules, no meetings, no officers, no dues, no headaches. Welcome aboard.

Build a couple of these cheapie boats and go out to the regular RC pond. Most RC boaters are not that familiar with micros, and they may be interested in seeing what the little things can do. Run them around enough and they may find a spot for you.

Better yet, see if you can find a small pond and get the owner to let you run there. Since these are so small, you do not need a big body of water. Something in the neighborhood of half an acre is more than enough room. The small size of these boats also seems to lessen the perceived liability from the owner's viewpoint. You know, something like "Awww, what a cute little boat. How far away can you go with it?" is the usual response. How much damage can a 1-pound boat do at 35 mph? Probably a lot less than a 20-pound boat at 70 mph I would presume.

Stay tuned, this will be a fun build and the results will be.........

Fast, Cheap, and Out of Control

[smm_cbf]

what you just said makes me feel alot better, i got my boat up for sale now, i have to sell my other boat in order to build one of two of these boats. i kind of like the mhz shovel nose, and the geko.

[Dr. Jet]

The Gecko is a RIOT with this motor and an 1850 mah LiPo. We spend more time laughing at the antics they perform rather than racing them.

[smm_cbf]

ya they sound like fun. but im pretty busy also though, i have band pratice all the time, so im thinking of ether an mhz boat or the aquacraft alligator tour boat seems like alot of fun also.

[mhall]

Hi Dr. Jet!

I thought this was the forum your were talking about. Thanks for the link! I really like your concept. I have two boys who I would love to get involved with this, and at these prices I think it's really feasible. I will keep watching this thread to see what you do with them.

Thanks,
Mike

[Flying Scotsman]

Dr. Jet

You are the man and I believe I have the stature of honourary member from 3 months ago.

Cheers

Douggie

[J Solinger]

OK, here are some photos of my inventory. You can see I am making a paper template for the forward bulkhead. I will scan it and bring it into AutoCAD as a photo image. Then I trace it in AutoCAD, print some copies, cut them out to test-fit in the hull. When everything fits, I do the same with the transom and the stringers. Then to the laser-cutter guy for a bunch of pre-cut plywood parts.

The photos show the MHZ shaft and rudder, the bearings and if you look, the CF tubes. The little bit of aluminum angle is for the turn fin mount.

Here is an interesting thought. I have some of Joe's hardware on my Campbell Classic. His equipment is some of the nicest work out there. How about a micro strut and rudder Joe?

It's something that has been on and off the table for a couple years. Maybe now is the time. Hardware does seem to be the sticking point with micros.

[Dr. Jet]

The Gecko is real quick to build. It comes with hardware and driveshaft installed. The hardest part is enlarging the motor mount holes for the bigger screws and filing down the sides of the motor mount tube to make room for the heads of the motor mounting screws.

[Dr. Jet]

Wow, two posts while I was typing that last one!

Douggie,

There are SLOBS popping up everywhere!!!

Joe,

I'd love to see what you would create.

[J Solinger]

What is the transom width and height on the bby hydro? I will do some chewing on it.

[Dr. Jet]

Transom dimensions

Allowing for some trimming, 1/2" high x 4-1/8" wide.

[Dr. Jet]

Motor and ESC

Here's the "Spec" motor and controller.

[Dr. Jet]

My first group of photos showed the MHZ 2mm stainless steel propshaft. This particular shaft has been shortened to fit the Geckos. I do not recall exactly how much I cut off to make them fit. I just ordered more propshafts from MHZ, and my plan is to size everything and locate the motor according to the full length of the stock shaft with no trimming. The idea here is that the longer the shaft is; the flatter the propshaft angle will be. When the propshafts arrive, I’ll cut a stuffing tube to length, and have my driveline ready to install. Cheap and simple! For those planning a similar build, not cutting the propshafts is one less step in building your SSSH racer.

I already have the motor and coupler drawn in AutoCAD; so once I have the exact length measurement of the shaft, I can finalize the motor location and shaft angle. Once I have that, I can start designing the plywood parts.

Stay tuned for more.

[Dr. Jet]

Designing the Internal Framework

I will be starting on my preliminary CAD drawings for the wood parts when I get home tonight. At this point, without the driveshaft, I will focus on the forward bulkhead, the stringers, and the transom. My ultimate goal is to tie all the various structural members together to eliminate stress risers or flex points, and create a light, yet stiff structure.

To this end, the motor mount will be tied to the forward bulkhead and the stuffing tube, and this entire assembly will be tied to the transom. This should eliminate hull flex where the stuffing tube passes through it, and maintain motor/prop shaft alignment. The motor mounting holes will be “slots” to allow easy motor installation and removal in a somewhat cramped area. The transom and forward bulkhead will be tied to the stringers, which should yield a very stiff structure without a lot of weight. The framework alone will have very little resistance to tensional loads; however, when “skinned” with the hull which will act as a shear member, the resulting structure should be extremely stiff, especially considering the small size. Remember that the bending moment of a piece is essentially a function of the cube of the aspect ratio of the part, and the smaller the part, the stiffer it is. This same stiff structure result has been achieved in the Campbell Classic, and now in the Vac-U-Pickle. The plywood parts for the MTH will have a “lattice” appearance to reduce weight while maintaining the shear resistance of the individual plywood parts. For test-fitting, I will run a print of the drawings, and paste them on some scrap balsa I have in my shop. Then, I will rough-cut the parts from the aforementioned balsa sheet (without the lattice work, of course) with an X-Acto knife and test-fit them in the hull to confirm that everything fits according to plan.

When everything fits, it will be time to start talking to the laser-guy.