Dr Jet,
Is the frame work part of the normal build or is it a Santee Lake special build ?
Manny
Dr Jet,
Is the frame work part of the normal build or is it a Santee Lake special build ?
Manny
I've glued the framework together, and sanded a few spots and it looks like it is going to work. For some reason, I think I'm probably not going to do much more work tonight.
Tee many martoonies:
I'm not under the alcafluence of incohol, though thinkle peep I am. I'm not half as thunk as you drink, yet I fool so feelish........
Last edited by Dr. Jet; 06-21-2008 at 07:59 AM. Reason: Tee many Martoonies:
Manny,
The framework is a "Dr. Jet - Super-Custom SSSH" build.
If it works out to my satisfaction, I may make them available to the masses.
I am thinking your mini builds will work well at the lake I run in up here in the L.A. area. Hansen Dam. We have some new Mini Rios running here now and I think the guys might be hooked on the small stuff now, plus the bigger faster boats run out of room real fast.
http://www.rcgroups.com/forums/showt...01819&page=125
Manny,
I looked at Tom's (Kmot) Mini-Rio video. You and Tom need to come to Santee and race against our SSSO Geckos. You may be in for a surprise.
Thanks Joe,
I know your work, and coming from you, that is quite a compliment.
I am making small changes here and there to the drawings to improve the fit. A couple of thousandths here and there kind of thing. The nature of vacuum-forming makes a perfect fit difficult. Randy's molds are hand-made, so they are not 100% symmetrical, If they were CNC machined, I would expect complete symmetry.
My plan is to get the framework close, and take up any gaps with the expanding PU glue.
Thinned epoxy has been applied to the framework. Once cured. I'll glue the tuffing tube to the assembly and be ready for installing the frame into the hull.
Last edited by Dr. Jet; 06-21-2008 at 10:37 AM. Reason: Typos, add notes
I needed to find a way to secure the bearings in the CF stuffing tube, yet still allow removal. Additionally, I wanted to make certain any thrust loads at the prop would be transferred to the inner race only. I did not want the propeller boss rubbing against the face of the bearing. I discovered that a small bit of antenna tube was a snug fit on the 2 mm propshaft and would solve both problems. I can adjust the location of the coupler on the motor shaft so that it just contacts the tube spacer at the motor end of the propshaft. The way this is laid out, the 2 mm prop shaft ends just a few thousandths from the end of the motor shaft. I'll post a photo of this before I glue it all together.
Last edited by Dr. Jet; 06-21-2008 at 11:04 AM.
Looking good.
How much affect with the large stuffing tube have compared to a smaller tube not utilizing ball bearings?
How big of an OD is that tube anyhow, it does look big...
Also I was wondering if you were going to toss the CAD files up for those of us adventurous enough to make these by hand :)
The stuffing tube is 1/4" diameter(give or take), and has the same diameter as the prop hub. No problem. It is no larger than your run-of-the-mill strut.
The framework has been glued in with the expanding PU glue. This stuff foams up quite a bit. you can knock down some of the unsightly bubbles while the glue is curing if you keep an eye on it throughout the process. If not, you will get a bunch of bubbles in the glue like I have here. The glue bubbles have no impact on the strength or performance of the hull, so I'm not concerned about them.
The second photo shows the fit of the prop shaft / motor shaft.
Last edited by Dr. Jet; 06-22-2008 at 10:49 AM. Reason: Edit grammar
Time for floatation. I try to make mine structural as well and here is how I do that.
First, I cut the foam to the approximate shape, and chamfered the edges where the glue joint in the hull interfered with the foam. Remember, the fit does not have to be perfect, since the glue will fill in most gaps. When it was time to glue it up, I coated the foam side of the framework with epoxy. Next, I coated the inside bottom of the foam with a zig-zag bead of PU glue. Then, I inserted the foam, taped the framework tightly to the foam, set the sponson on a flat surface, and placed a heavy weight on the foam. A can full of lead shot works great. The idea is to keep the bottom of the sponson flat and not to puff out when the glue expands. I will not put glue in the sides of the sponson just yet, and that will give the glue a place to expand along the anti-trip portion (beveled outside edge) of the sponson.
Last edited by Dr. Jet; 06-22-2008 at 12:24 PM. Reason: Edit Photos
I've trimmed the foam and test-fitted the deck. I marked the stringer locations on the deck where I will apply the PU glue. I will also add PU glue to the top of the foam, in the space between the foam and sponson sides (just a little here), and in the front of the sponsons (again, not too much).
Note I have a different beverage of choice this morning.
I applied glue to the hull halves and I'm about to join them.
Here it is. It is incredibly stiff yet light. The sponsons are solid as a rock and ready for race/ramming conditions.
Last edited by Dr. Jet; 06-24-2008 at 11:40 AM. Reason: Edit syntax error
Where are the batteries going? forward of the motor?
Jim
"Our society strives to avoid any possibility of offending anyone except God.
Billy Graham
The batteries in all my little micros wind up behind that center bulkhead. The servo and receiver go on the other side.
Here I have temporarily stuck a servo, the rudder, the ESC and a receiver to see where the battery will be for a reasonable balance point of 1/2" behind the sponson for starters. I did something similar to this when I first started, so this confirms my layout. I will have room to move the battery both directions for fine-tuning.
I have had some very interesting conversations with several people regarding micro hardware. As things stand right now, there is not much available. MHZ has some nice stuff, but not too many people have been using it (I personally like it). There is that blue anodized hardware that Steve is selling as "micro"; but in my book, it is still a little large for hulls like the BBY MTH, the MHZ shovel, and H&M shovel. I used the rudder in my Micro Scat Cat, and it seems a bit large for that as well. Furthermore, that hardware does not perfectly fit Octura props without some adjusting. Octura has some small stuff, but again the mounting bits are a bit large for the small transoms on the micro hydros.
For those of you considering a build like this, hang on for a little while. I'm thinking there may be something WAY cool coming down the pipeline. I'm not yet at liberty to release all the details, just be advised that something is in the works. I haven't talked with Randy regarding the laser-cut parts, but I am open to the idea of making the wood parts available to the masses, either through Randy or through my own business.
A lot will depend on how well this straight-shaft setup works out. If it sucks, I have some ideas for a micro wire drive that will allow for prop angle and depth adjustments. I have high hopes for the straight shaft, and think it is a great option that reduces the amount of "futzing around" to get things right.
SSSH may be on the verge of "catching on".
There will be a small hiatus in the MTH build over the first week in July. I’m going to fly my motorglider to Bishop and spend the week soaring the White Mountains and the Sierras.
Look for the first “sea trails” to be somewhere in the middle of July.
Last edited by Dr. Jet; 06-25-2008 at 10:42 PM. Reason: Add Vacation Schedule and Motorglider Photo
Now that the hull halves have been joined, I brushed some epoxy into the gap between the lip and the hull, then filled the gaps by “smooshing” a thickened epoxy/cab-O-sil mix into any gaps with my fingers (yes I was wearing gloves). Then I wiped-down the hull with a paper towel dampened with denatured alcohol to clean-up any excess. This fills the lip of the “shoebox” lid and seals the hull.
Remember that the top/bottom hull joint is full of expanded PU glue, so if I want to trim the lip in the future, I can without worries of structural damage. There may be small gaps after trimming the lip, but again, thickened epoxy will fix that.
Normally, I would build-up the ride surfaces with thickened epoxy to get sharp corners and flat surfaces. In order to get this on the water as soon as possible to see if it even works, I think I’ll just glue on some sheet styrene ride pads, and call it good enough. I can always come back later and do the epoxy build-up and sharpening of the edges if the hull/setup shows promise.
Good Deal Bill,
Mine will be here real soon. I bought the same motor you did! So I will have my very own SSSH (Whatever that means! lol).
Im going to do a wire drive, already know that. If a hardware package is available for reasonable I will get it, otherwise make my own. Im not to sure on that yet.
Santee Sport Scale Hydro
Many people turn up their noses at a straight shaft in a hydro. Yes, they do not allow any adjustment in depth or angle, but they are by far the smoothest running, most friction-free way of getting power to the propeller. When I started this build, I spoke with Randy about the prop depth settings he found that worked, and set this hull up at the same depth. The angle was determined by the length of the shaft and the diameter of the motor.
Just as in full-sized hydros, the ride is controlled by the balance of the hull and the type of prop. I will only be using low-lift props, and I have done what I could to reduce the shaft angle.
Another reason for the straight-shaft setup I did is cost and parts availability. Everything is off-the-shelf and low-priced.
Before you commit to using a wire drive, let's see if this straight-shaft works in an acceptable manner. The results may be surprising (then again, they may not).
Patience Grasshopper.
The build is coming along great I still need to paint my little Hydro, Oh so much to do.
Randy,
If this works out, we should talk about my CAD files for the laser-cutting of the framework. I always like to "barter" if you follow my drift. Looks like I may need some more hulls in the future. I have more prototype laser bits (I managed to get several on one sheet), and if this test hull works out, I might build a "pretty" one for a keeper. I may give this test hull to a buddy that is not as skilled in his building ability.
Well I just got my boats in the door today.
You are correct, there isnt much room at all on the back of the Hydro! Im guessing when I get it trimmed up I will have about 3/4" max.
Awesome build DrJet.
I have this power system in my hydromite and it is stupid fast you will most likely need to add forward weight (of course the straight shaft will probably scrub some speed off yours)
Keep up the good work and let us know about getting your inter structure for our boats.
The Manx has been sitting dormant, but I think I finally have my motivation back. I hope to see it float soon.
dammmm i need one of those what is the size of it?
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