HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Dec 28, 2009, 03:21 PM
Registered User
Chinewalker's Avatar
1000 Islands, NY
Joined Dec 2009
462 Posts
Build Log
Hedlund Class B Outboard Hydroplane

BOAT: A mid 1970s era Hedlund-copy B-25SS Hydroplane. 1:1 scale length is 9'6". Model's scale is yet to be determined. I am currently drawing the frames and shapes in 1:8 scale for 1/2A power, but may scale them up for an Aquacraft EP1 or Graupner GTX 650, if I can find one. The Hedlund was a popular stock outboard design back in the 1970s and incorporated an air entrapment bottom, often called the Hedlund Hump. My boat was a copy or "splash" of a Hedlund.

Nearly 10 years after I first hatched the idea, I am finally at a point where I can build my boat! I drew up some rough sketches for it back then, but didn't get very far as I ended up moving and lost my model shop. I now have a nice basement shop and I'm ready to begin! I spent a good hour over the weekend with the 1:1 boat, measuring, taking photos, etc. Spent some more time on the computer drawing up the frames, transom, cockpit coaming, etc. Still have a ways to go, but it's starting to take shape!

To get started, here are some photos of the 1:1 boat...
Chinewalker is offline Find More Posts by Chinewalker
Reply With Quote
Sign up now
to remove ads between posts
Old Dec 29, 2009, 11:27 AM
Registered User
Chinewalker's Avatar
1000 Islands, NY
Joined Dec 2009
462 Posts
Frame Drawings

I decided to move forward with the 1:8 scale version. I figure I can make my mistakes and tweak things in the smaller scale without committing as much in the way of materials. If it works alright in 1:8, I think I'll go on to the 1:4 scale for the EP1.

Here's what I've got so far...
Chinewalker is offline Find More Posts by Chinewalker
Reply With Quote
Old Dec 29, 2009, 03:56 PM
GILL
GILL RC's Avatar
United States, NJ, Hopatcong
Joined Aug 2005
2,575 Posts
Got to love the neel-downs, fun to drive. Last one I had I had purchased an 8 footer for my step son. rebuilt it and painted it in Dallas Cowboy colors, with the blue stare on the nose. He then sank it in lake George with my buddies new 10 horse Johnson on it. I had floatation and it just tomstoned. Throw a line on the bow hook and pulled it back level dumping most of the water out. Buddy was not very happy.
GILL RC is offline Find More Posts by GILL RC
Last edited by GILL RC; Dec 29, 2009 at 04:02 PM.
Reply With Quote
Old Dec 31, 2009, 11:03 AM
Registered User
Chinewalker's Avatar
1000 Islands, NY
Joined Dec 2009
462 Posts
Revisions made..

Thanks John! I tweaked the frames and made a template for my cutouts. Hopefully I can start cutting and gluing this weekend! I ordered a Graupner GTX 650, which may eventually find its way onto a larger version of this.
Chinewalker is offline Find More Posts by Chinewalker
Reply With Quote
Old Jan 01, 2010, 04:39 PM
Registered User
Chinewalker's Avatar
1000 Islands, NY
Joined Dec 2009
462 Posts
Assembly begins...

Got a good bit done today. Coamings and most of the framing put together. With a little imagination, it's starting to look like a boat! I used mahogany planking for visible areas and balsa for the frames and cross members.
Chinewalker is offline Find More Posts by Chinewalker
Reply With Quote
Old Jan 03, 2010, 05:38 AM
Registered User
Chinewalker's Avatar
1000 Islands, NY
Joined Dec 2009
462 Posts
Framing Done!

Got a lot done Saturday morning...

The framing is pretty much done. I still need to add pieces for the sponson chines, but that's it. I even started skinning it last night, adding the rear chines with the "chicken wings". For the uninitiated, my 1:1 boat has a raised portion of the rear, starboard chine called a chicken wing. It was added after the boat was built to reduce the chance of digging the chine in a turn and flipping. Later versions had it as "standard" and many had them on both sides to maintain symmetry, although you'd never turn right hard enough to dig the port side chine.... I decided to go with symmetry on the model version.

I simplified the design in several areas. My original plan was go go for full frame and batten build, but decided to do more gluing and less cutting. Makes for a much quicker build.

I used solid balsa blocks for the bow area to give a bit more impact resistance over battens should we ever contact a dock head-on.
Chinewalker is offline Find More Posts by Chinewalker
Last edited by Chinewalker; Jan 03, 2010 at 05:49 AM.
Reply With Quote
Old Jan 03, 2010, 11:25 PM
Taking care of the pond.
MILLERTIME's Avatar
USA, CA, Fresno
Joined Apr 2004
7,296 Posts
Starting to look like a boat.
MILLERTIME is offline Find More Posts by MILLERTIME
Reply With Quote
Old Jan 04, 2010, 01:50 PM
Registered User
Weare NH
Joined Nov 2007
502 Posts
http://www.rcgroups.com/forums/attac...mentid=2969521

YOUR going to need a bigger BOAT!!!
Bob Big
Bob Bighinatti is offline Find More Posts by Bob Bighinatti
Reply With Quote
Old Jan 04, 2010, 02:09 PM
Registered User
Chinewalker's Avatar
1000 Islands, NY
Joined Dec 2009
462 Posts
Yeah, the single cylinder .049 looks much better on there
Chinewalker is offline Find More Posts by Chinewalker
Reply With Quote
Old Jan 04, 2010, 11:45 PM
Taking care of the pond.
MILLERTIME's Avatar
USA, CA, Fresno
Joined Apr 2004
7,296 Posts
You have some nice old Outboard's.
MILLERTIME is offline Find More Posts by MILLERTIME
Reply With Quote
Old Jan 05, 2010, 08:49 AM
Registered User
Chinewalker's Avatar
1000 Islands, NY
Joined Dec 2009
462 Posts
Sponson chine planking...

Back to the work week so shop time was short. I did get the sponsons faired in and glued the chine planking onto the sponsons. Hopefully I can get the sponson bottoms on this evening and then I can seal up the insides with West System epoxy.

A couple folks have asked about the butt joints I used for the cross members, etc. - I did that on this boat simply because it likely won't see much water time. I am doing this one more as a proof of concept hull just to make sure my lofting and drawing work went well enough to move onto the larger version. Strength, although important, was secondary to making sure I got the various alignments and curves right. At 14-inches long, it doesn't weigh much and the stresses if I do run it with a 1/2A outboard are minimal. The West System that I'm sealing it with will greatly strengthen what's there, too. On the larger version I will notch the cockpit coamings to run the frames chine to chine, and will also run the lateral battens full length on the sides and chines.
Chinewalker is offline Find More Posts by Chinewalker
Reply With Quote
Old Jan 05, 2010, 09:33 AM
GILL
GILL RC's Avatar
United States, NJ, Hopatcong
Joined Aug 2005
2,575 Posts
Very nice. You are righ the stress will be light. he Atwwods are pretty smooth rinning I orefer the Sea Fury.
They aer on my site at www.jsgill.net I've been collecting the outboards for over 50 years.
GILL RC is offline Find More Posts by GILL RC
Reply With Quote
Old Jan 05, 2010, 03:49 PM
Registered User
mxz70017's Avatar
Joined May 2006
911 Posts
Looking Good!!!

Hey Its starting to get It's look's now.Love getting some skins on an see how It look's!!!Alway's better then the bare frame look.Get some 3/4"an 1" as well as a 2" roll Of blue painter's tape.Sticks well to wood!!! Use It In cut piece's to hold things together.I use more tape now then I do clamps. It don't deform an crush balsa stick's either.
mxz70017 is offline Find More Posts by mxz70017
Reply With Quote
Old Jan 06, 2010, 10:37 AM
Registered User
Chinewalker's Avatar
1000 Islands, NY
Joined Dec 2009
462 Posts
Bottom Sides DONE!

Got a little more work done last night and this morning. The sponson skins are on and mostly shaped in! Still have a little fairing to do, but they're more or less finished!

MXZ, thanks for the painter's tape idea. I'll get a roll and try it out... It definitely would have made a few things easier...
Chinewalker is offline Find More Posts by Chinewalker
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
For Sale K&B 11cc Outboard Engines getnoff Boats (FS/W) 2 Dec 16, 2009 01:05 PM
Discussion rc nitro 7.5 k&b outboard 1428 Racing Boats - Internal Combustion 12 Oct 27, 2009 10:51 PM
Sold K&B outboard parts. warrgy69 Boats (FS/W) 0 Oct 08, 2009 05:38 PM
Sold Outboard Marine Engine K&B 3.5 clif Boats (FS/W) 0 Sep 29, 2009 09:25 PM
Discussion K&B 7.5cc outboard tmattusa Racing Boats - Internal Combustion 8 Sep 05, 2009 11:17 PM