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1/8th Scale Hydro Build

Old 12-02-2006, 12:18 AM
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Hydro Junkie
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Default 1/8th Scale Hydro Build

After many false starts and delays, I finally have enough pictures to start a build thread. For those that want to build along, I will be going over some things that need to be done BEFORE BUILDING STARTS. Here is a PREBUILD hit list of must do's:
1) PREPLAN YOUR SYSTEM LAYOUTS AND ACCESS
2) PREPLAN HOW YOUR "TOPSIDE PARTS" WILL BE MOUNTED AND RETAINED
3) BUILD A JIG
4) PREPLAN YOUR MATERIALS USAGE
5) KNOW WHAT TOOLS ARE AVAILABLE



I will go over each of these in the next few posts so they are easily understandable to all
Old 12-02-2006, 12:54 AM
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Hydro Junkie
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Default RE: 1/8th Scale Hydro Build

Preplanning how your boat's systems will be layed out and accessed is probably the most overlooked area of boat building. I've seen on numerous occassions a new boat brought to the lake, only to have problems. It could be a sticking rudder pushrod on a gas deep vee or a tangled line on a racing sailboat's sail winch, but either way, by not planning for access to these areas, the boats had to be taken home and reworked. How your radio gear, fuel and cooling system is set up must be planned so that it can be installed AND made accessable during the build. This can mean running tubing though bulkheads for easy connections or predrilling holes as needed. Here is an example of how I made the fuel tank accessable and installed the cooling system in a Sport 40 built from the same plans as the 1/8th scales in this build. I did make a mistake on the cooling system, however. The supply line came out too short and I tried to make it work. It now interferes with the starter belt, so before I can put the deck on the left side, I need to rework the tube, moving the location in the engine bay forward and adding support where it runs through the cross frames
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Old 12-02-2006, 01:09 AM
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Hydro Junkie
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Default RE: 1/8th Scale Hydro Build

The second most overlooked area of building a boat is how to mount and retain parts like tails and cowlings on your boat. There are many ways of doing this, including the Dumas technique of cutting a slot in the deck and epoxying the tail in. While this may seem like an easy answer, it has a major drawback; if you blow over your boat, it can destroy the tails and deck. This is why scale hydroplanes are designed to come apart in the event of a flip or collission. Brackets attached to the deck with nylon screws is the most common way of attaching tails, while twin roller cabinet latches in conjunction with hold down pins are the most common for cowlings, though slide latches are also becoming more common. I will go into more detail later in the build on some of the options available.
Old 12-02-2006, 01:30 AM
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Default RE: 1/8th Scale Hydro Build

When building a hydroplane or tunnelhull, the most important tool you will use is a building jig.
The building jig serves three purposes:
1) It keeps the sponson insides parallel and the hull square
2) It provides a flat building surface to keep the bottom flat between the sponsons
3) It makes moving a very weak framework movable without being twisted

Why these are so important isn't obvious till a new boat is run. A non-square hull won't run straight and is hard to dial in, especially in the turns. A bottom that isn't flat can and will make an otherwise good boat into a dog that won't fly like it should. A twisted hull will affect the boats ride due to the sponsons not being level with the rear of the hul, whichl can induce blow-overs and bad handleing characteristics.
There are two kinds of jigs used in boat building, the flat jig(which I normally use) and the bottom contour jig. The flat jig works well for boats that don't have a belly pan, so older style hulls can be built easily with one. Newer hulls, like some of the Turbine Budweisers can have a belly pan integrated into the engine bay sides. These require a bottom profile jig. Tho bottom profile jig has one end built up so that multiple boats of the same design will be vertually identical. Why they are preferred to the flat jig for boats with an integrated belly pan is the belly pan is lower than the bottom of the hull, so a lower area can be built into the jig to allow for the pan. I will be showing how I build a flat jig later in the thread.
Old 12-02-2006, 01:55 AM
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Default RE: 1/8th Scale Hydro Build

Preplanning on how you are going to use materials can be beneficial to saving money during your boat build. My list of materials for either of the hulls I'm building in this thread is as follows:
1 12X24X1/4 five ply aircraft grade ply
1 12X36X1/8 five ply aircraft grade ply
6-7 12X48X1/16 three ply aircraft grade ply
2 48" 1/4 square spruce stock
12 36" 1/4 square spruce stock

By minimizing scrap, I can probably get each hull using 5 or six pieces or 1/16th ply, though in this case, I'm using 60" square sheets, which is the equivalent of 5.25 12X48" sheets from the LHS. By laying out the parts as close as possible I can get all the framing and part of the skin for both from one sheet. I did make one mistake with these large sheets, however. I left them rolled up too long, so they now have a curl that I will have to deal with through out the build. Check out these pictures and you will see what I mean
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Old 12-02-2006, 02:19 AM
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Default RE: 1/8th Scale Hydro Build

Tools, either you have lots of them or you don't. For those of us that do, building a boat isn't a hard proposition. Band saws, scroll saws, table saws, routers and shaper tables, belt and disc sanders, Dremel Tools and clamps make the job of cutting, shaping and epoxying parts simple. But what about those that don't have a lot of room to accumulate and store all of those tools? Besides clamps, you can get by with three tools:
1) a jig or coping saw
2) a drill
3) a hand held belt sander

Believe it or not, these three will do about 95% of what a whole garage full of tools will. It will take a little longer in some cases, but they will get the job done. I found it easier to rough cut my parts out of my large piece of 1/16th ply with my jig saw BEFORE using other tools to finish the job. Having something to work on(a Workmate or a couple of folding saw horses) makes it easier as well.
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Old 12-02-2006, 02:39 AM
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Default RE: 1/8th Scale Hydro Build

So much for the pre-build lecture
I don't know about all of you, but I think its time to start making some sawdust.
I started out by tracing the parts out from the part sheet with tracing paper and a pencil. This was followed by going back over the traced outlines again, this time with carbon paper between the tracing paper and the 1/16th ply. When I had transferred the sponson insides and one set of engine bay sides to the plywood, I took them outside and, using a jig saw, roughly cut out the sponson insides. The parts were then taken into the garage and were finished on the rear and bottom edges using a band saw and belt sander hooked up to a shopvac.
At this point, due to my curled plywood, I felt was the time to start attaching stringers to the sponson insides. Along the front of the sponson, a series of relief cuts were required to make the spruce bend as required. One thing I'd like to point out is the flat building jig I've used to clamp the wood to. This is from the Sport 40 pictured earlier.
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Old 12-02-2006, 03:02 AM
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Default RE: 1/8th Scale Hydro Build

After getting the sponson bottom stringer tacked in place, it was time to turn the panel over and install the stringers the bottom will be epoxied to. This is where I make the measure twice and cut once warning. I finished right sponson inside, but on the left one, I dodged a bullet. When double checking my layout lines for the stringers, I found that I had layed out the longer front section wrong. The error would have cost me about $10 between ruined stringer, replacement stringer and gas to get replacement stringer.
Since the stringers are installed on the first hull's sponsons insides, it was time to start to work on the 1/4" plywood parts
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Old 12-02-2006, 04:37 AM
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Default RE: 1/8th Scale Hydro Build

Now that I've gotten both right sponson transoms and one boat transom cut out, it's time for some test fitting. I dry fitted one sponson transom and rear transom to the sponson insides, finding only a little touch up was required. If you look closely at the ends of the transom, you can see the finished end lines. I didn't cut these flush due to the angle the nontrips will be attached at, which isn't a 90
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Old 12-02-2006, 04:58 AM
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Default RE: 1/8th Scale Hydro Build

I am going to stray a little from the build and jump ahead. I know some plan on building Turbine budweisers, so at this point, I'm going to show how the asymetrical Jones Sponson is different from the standard design used in the 1970 and into the 1980s. I have attached some pictures showing both Jones sponsons and the sponson inside and transom from the build thread boats. As you can see, the Jones sponson is built using FOUR skin panels compared to the earlier two. It also has FIVE 1/16th ply lengthwise frames instead of the single 1/4" square spruce stringer. Needless to say, the Jones sponson is considerably harder to build. Another difference is that the Jones sponson is supported by 1/8th" 5 ply aircraft ply instead of the 1/16th" 3 ply aircraft ply of the thread boats. The Jones sponson also doesn't have the 1/4" stringer along the bottom of the sponson inside. Another thing with the Jones sponsons is they are not the same width. On the scale boats, the left sponson is a full inch wider than the right. This causes a problem on frame 10, which is drawn too wide to work in the right sponson. There is a way to fix it, which I will show later in the thread.
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Old 12-02-2006, 01:07 PM
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Default RE: 1/8th Scale Hydro Build

Are you tacking the stringers on with epoxy or CA? Whats the the general rule for the distances between cuts in the stringers to bend them for the sponsons?
Old 12-02-2006, 01:23 PM
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Default RE: 1/8th Scale Hydro Build

I tacked them with CA around the bend on the sponson and ran a line of CA down all the straight runs. Later in the build, they will get coated with slow set epoxy, as well as getting more epoxy when the skin panels are attached. To date, I've never had one fail. This is, of course, personnal preferance. If others want to attach the stringers with epoxy, who am I to say they are wrong. After all, I'm not a professional builder

As for the relief cuts, mine averaged out to approx 3/8"+1/16 and were all hand cut using an Exacto razor saw about half way through the stringer.
Old 12-21-2006, 06:07 PM
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Default RE: 1/8th Scale Hydro Build

HJ, Is there anymore progress? I need your postings for future reference
Old 12-21-2006, 10:11 PM
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Default RE: 1/8th Scale Hydro Build

Probably after the first of the year. Been spending all my time on the dreaded "Honey Do" list, which includes working on the barn.
Old 12-23-2006, 06:21 PM
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Default RE: 1/8th Scale Hydro Build

Dose anyone have plans for a building jig for a Hydro?
Old 12-24-2006, 10:49 AM
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Default RE: 1/8th Scale Hydro Build

I think all you have to do is follow the bottom outline of the center section of the boat and go from there. I a nutshell
Old 12-24-2006, 09:00 PM
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Default RE: 1/8th Scale Hydro Build

Archer7153, what boat are you building, a kit or a plan built boat?
Old 12-24-2006, 11:46 PM
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Default RE: 1/8th Scale Hydro Build

[][][] hi there! Can anybody tell me where is the C of G located on a Hydro(picklefork) or how to calculate a start position at least??????
I am currently modifying an abs electric arf hydro but need at least a start position for the C of G as I don`t think the original was anywhere near it!! I plan on putting two 3300nmh batteries in the sponsons but they will not be accessible once the top and bottom have been rejoined. Any assistance would be greatly appreciated. Thank you.
Old 12-24-2006, 11:55 PM
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Default RE: 1/8th Scale Hydro Build

I dont have a CG for ya, but this boat will run for 7-10min then you will need to plug the boat in to charge the unremovable batteries? Ya sure ya wanna do that?



Merry Christmas

Paul
Old 12-25-2006, 10:49 AM
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Default RE: 1/8th Scale Hydro Build

Hydrojunkie,Stuped question or not?Can a someone build a 1 /12 or 1/10 scale boat out of wood?[>:]
Old 12-25-2006, 03:25 PM
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Default RE: 1/8th Scale Hydro Build

HydroJunkie, I have plans for a Pickle Fork, the Tide Hydro and a Shovel. I am working on the shovel first.
Old 12-25-2006, 03:27 PM
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Default RE: 1/8th Scale Hydro Build

I have these plans too for smaller boats. http://216.120.233.47/buildoff.htm
Old 12-26-2006, 12:51 AM
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Default RE: 1/8th Scale Hydro Build

Hey there gooycheese. Yeh I will still have the speed controller and battery connection in the access hatch so i can do the charging via that connection[X(][X(]
Old 12-26-2006, 09:20 AM
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Default RE: 1/8th Scale Hydro Build

I'm looking for alittle big then these boats and alot new style/models of hydro planes.The reason why I'm looking/wanting one is because,I have a Proboat Miss Bud and I'd put a.21 in it.Now I'm seeing why hydrojunkie was stessfulling saying that these boat hulls cant take the stress of a .21s in them.I have more cracks on the bottom of my boat!!So if I build a wooden Miss Budwiser 1/12 or 1/10 one it should take a better beating and take the stress of a.21 motor.
Old 12-26-2006, 06:02 PM
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Default RE: 1/8th Scale Hydro Build

Misshydro, Can't you reenforce the inside of the hull with fiberglass? Or is there no room? BTW the vids of your boat were awesome.

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