Outboard Kneeler Hydro - Hedlund 1/4 Scale - RC Groups
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Jan 11, 2010, 05:05 AM
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Chinewalker's Avatar
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Outboard Kneeler Hydro - Hedlund 1/4 Scale

I have a build thread going in the scale boats section for my 1/8 scale version, but I figured this was a better spot for the 1/4 scale hydro. This is my first full R/C build. I will be running a Graupner GTX 650 on it to start with.

I started cutting this weekend, getting the main coaming girders cut and shaped, and then joining them with the transom and crossmembers. I've never built a model this large! This should be fun!
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Jan 11, 2010, 08:18 AM
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Chinewalker's Avatar

Framing coming together...

I got all the main frames in last night...
Jan 11, 2010, 01:27 PM
Grumpa Tom
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Jan 11, 2010, 07:32 PM
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MarcRacer18's Avatar
Nice strart!
Jan 13, 2010, 11:33 AM
Capt.Crash's Avatar
Ah...nice simple clean lines...maybe I should have done something like this.

Looks good so far.
Jan 13, 2010, 03:15 PM
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Chinewalker's Avatar

1:1 Boat

Awhile back someone asked me what the real boat looked like underway. I found a pic of my Dad driving it with my 1952 Mercury KG-7H Hurricane on it. This was the first motor I ran on the boat when I got it. It did about 45-48 mph with that motor. It wasn't a bad set-up but the boat really came alive when I put a 1980 Mercury 25SS on it and it would nudge 60mph. The boat really likes to fly and doesn't pack enough air under it to float it until it hits the mid 50s. It's kinda like riding an elevator - your gut gets that sinking feeling as the boat just lifts up about 6-inches off the water and just hangs.
Jan 14, 2010, 01:59 AM
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Amp Abuser's Avatar
Where was the CG? Looks like it was back quite a bit base on the picture.
Jan 14, 2010, 05:31 AM
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Chinewalker's Avatar
The CG in an outboard hydro is considerably different than that of an inboard hydro. With the driver and motor the center is well back of the sponsons.
Jan 14, 2010, 12:24 PM
RELAX. You'll live longer
785boats's Avatar
Looks good . Great subject for a model.
Are you going to fill the spaces between the bulkheads with foam before you put the skin on? Certainly makes for a stronger hull & it won't sink if you have a serious crash.
Jan 14, 2010, 12:54 PM
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Chinewalker's Avatar
Would I use a pour-in foam? I have some 8 lb. density 2-part left over from a 1:1 project.
Jan 14, 2010, 04:33 PM
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mxz70017's Avatar


I would not use a commercial grade 2 part foam.They make one for models.Its a low E ok.The stuff you use for a real boat or home.Will expand way to much per volume an will blow that frame apart.What most do an I would do on that balsa frame.Is use a closed cell Ridgid foam board. An cut an shape It. To fit between the bulkheads.Make sure It Is a closed cell foam!!!If not the open cell absorbes water an that's not good...

Hey also looking good...See you put In some cross members to stiffen It up.
Last edited by mxz70017; Jan 14, 2010 at 07:44 PM.
Jan 14, 2010, 04:46 PM
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Chinewalker's Avatar
Thanks! I have some closed cell foam board I can use....
Jan 15, 2010, 09:15 AM
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Chinewalker's Avatar
Thinking out loud, and having Googled around a bit on building RC outboard hydros, I am now wondering if I should be building this in wood over foam construction? I really don't have a whole lot of time or money into it so far, so it wouldn't be hard to backtrack and start from scratch. Coming from a 1:1 boating background, my first thought was to build it plank over frame like a real boat, but now I'm having second thoughts.... Any input?

- Scott
Jan 15, 2010, 12:46 PM
RELAX. You'll live longer
785boats's Avatar
No need to change what you've done so far.
Just put the bottom & side skins on, as you were going to do. Then cut & fit the blocks of foam to each section & glue them in, leaving them a bit proud of the deck bulkheads & frames. Then carve & sand to shape. Then glue on the deck skin. That's the way I do it anyway.
All the best.

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