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Cox Engine of The Month
Roddie-Rigger.. a 2005 original design
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Roddie-Rigger.. a 2005 original design
I thought-up this outrigger model boat design almost 20 years ago when I worked at the sign company. I ran CNC routers that were used to cut dimensional graphics made from foam-board (3/16" through 3" thicknesses...) balsawood, ply/hard wood, PVC, polystyrene, acrylic, aluminum.. lots of materials that lent themselves to my hobby interests. I was able to do some CAD while the machines were on long-running jobs. The outrigger was just one of quite a few CAD projects that I was able to create and cut.
Here's a CAD image of all the parts that make up the rigger-design from back then. I could "pull" parts from this file.. and cut them from the various materials listed.
I made a boxful of parts that had been in storage since then.. and I had also mocked-up a hull that's been kicking-around.. well.. for way too long.. and has workshop-rash to prove it.
Shown below; with prospective Cox .049 reed-valve engine and 2mm shaft (wire) drive. This would come together quickly at this point/stage in time.
Since I've been sourcing parts for the Cox powered jet-pump.. it's rekindled my interest. I un-buried the rigger's box-o-parts and thought; "what a shame to let this keep sitting.."
Apparently I was confident in my design... because I made parts enough for several models..
Below image is of two differing profile foam-board sponson "blanks" and .030" aluminum sanding-templates to contour the foam to form a 90 degree (right-angle) or 60 degree angle at the step.
The aluminum boom stock tubing is used to hold the templates in alignment when sanding-in the contours.
These foam parts are of the polyurethane type and need to be "faced" with something smooth and lightweight. There's no wood to worry about here.. but unprotected foam gets dinged-up with discouraging ease. I've got some options.. it just depends on the method of adhering a given skin to the foam.
Here's a CAD image of all the parts that make up the rigger-design from back then. I could "pull" parts from this file.. and cut them from the various materials listed.
I made a boxful of parts that had been in storage since then.. and I had also mocked-up a hull that's been kicking-around.. well.. for way too long.. and has workshop-rash to prove it.
Shown below; with prospective Cox .049 reed-valve engine and 2mm shaft (wire) drive. This would come together quickly at this point/stage in time.
Since I've been sourcing parts for the Cox powered jet-pump.. it's rekindled my interest. I un-buried the rigger's box-o-parts and thought; "what a shame to let this keep sitting.."
Apparently I was confident in my design... because I made parts enough for several models..
Below image is of two differing profile foam-board sponson "blanks" and .030" aluminum sanding-templates to contour the foam to form a 90 degree (right-angle) or 60 degree angle at the step.
The aluminum boom stock tubing is used to hold the templates in alignment when sanding-in the contours.
These foam parts are of the polyurethane type and need to be "faced" with something smooth and lightweight. There's no wood to worry about here.. but unprotected foam gets dinged-up with discouraging ease. I've got some options.. it just depends on the method of adhering a given skin to the foam.
Re: Roddie-Rigger.. a 2005 original design
excellent work Rodie and as always, very organized!...it's good that you restarted those pieces that were waiting for you friend!
MauricioB- Top Poster
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Join date : 2016-02-16
Age : 53
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rsv1cox- Top Poster
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Posts : 10603
Join date : 2014-08-18
Location : West Virginia
Re: Roddie-Rigger.. a 2005 original design
rsv1cox wrote:Nice! I'm always impressed by your creative skills.
That little Cox .049 looks natural sitting in there, but what's the funnel behind/on the fuel tank?
Thanks Robert! That's a velocity-stack that I fitted to the choke-tube.
There will be an external fuel-cell of approx. 10cc capacity.. but I'm not sure yet what type I'm going to use.
Re: Roddie-Rigger.. a 2005 original design
Ah......A Cox Sure-Start. I should have known.
rsv1cox- Top Poster
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Posts : 10603
Join date : 2014-08-18
Location : West Virginia
Re: Roddie-Rigger.. a 2005 original design
rsv1cox wrote:Ah......A Cox Sure-Start. I should have known.
Yea.. that's what it looks like.. but I don't own any Sure Start engines Robert. I mix/match various engine parts to make custom configurations. That's what makes the Cox engines (especially the .049's) so much fun to work with.
The "Rigger" engine will undoubtedly morph into different configurations through both; bench-testing and "real-world" running on the water.
I'm working on a test-stand that will use a 2L. capacity bottle of water for the cooling coil around the cylinder-head.. to see how the engine behaves with a flywheel mounted "no-load" vs. a simulated working-load.
Here's some eye-candy..
The L-bracket on the back of the fixture is for a fuel-cell of some sort. Not sure yet; what that will be...
marine rudder, fins and trim-tabs
I searched and found a "rudder" on Amazon.. and for $10 (USD) got that plus turn-fins and trim-tabs in a replacement-kit for a small RC race boat that they stock. Amazon also offers through/below-the-hull rudder kits.. but those aren't what I would want to run on an outrigger hydro. Those below-the-hull rudders seem more appropriate for "scale-model" subjects.
This will work for the Roddie-Rigger..
This will work for the Roddie-Rigger..
getting back to the sponsons..
getting back to the sponsons.. I knew that I needed to "skin" the exposed foam sections (the tops and bottoms..) but wasn't sure what to use.. and I'm unsure about this choice.. but when you're designing something.. you just have to go with it sometimes. The exposed foam depresses/crushes easily if even slightly impacted. I thought about trying a skin of plastic "sheet-protector" material.. but it's too thin and too flexible to protect the foam. I needed a "shell" of sorts.. but not at a big weight penalty.
The bare "tub" with booms/sponsons is pretty light..
The sponsons are made from 1.5" "Ultraboard" a sign-grade foamboard faced both sides with .015" Polystyrene. So they're 1.5" wide.. which is what the skins need to be. The "sides" have the .015" Polystyrene facers. The Top & Bottom are exposed-foam that needs to be skinned.
I'm "going with" another sign-shop material that I had on hand.. which is .018" phenolic sheet. The sponsons measure 8.0" long on the top.. which is flat. The bottom skin needs to be longer at 8.312" because of the upward-sweep running from the step... to the up-swept front tip. I laid out skins for both; 60 & 90 degree versions. Eight strips @ 1.5" wide.
It's been coiled tightly........ ... so I need to try to flatten it out. I'm going to try weighting-down flat with books overnight.. and will check to see how/if it relaxes...
The bare "tub" with booms/sponsons is pretty light..
The sponsons are made from 1.5" "Ultraboard" a sign-grade foamboard faced both sides with .015" Polystyrene. So they're 1.5" wide.. which is what the skins need to be. The "sides" have the .015" Polystyrene facers. The Top & Bottom are exposed-foam that needs to be skinned.
I'm "going with" another sign-shop material that I had on hand.. which is .018" phenolic sheet. The sponsons measure 8.0" long on the top.. which is flat. The bottom skin needs to be longer at 8.312" because of the upward-sweep running from the step... to the up-swept front tip. I laid out skins for both; 60 & 90 degree versions. Eight strips @ 1.5" wide.
It's been coiled tightly........ ... so I need to try to flatten it out. I'm going to try weighting-down flat with books overnight.. and will check to see how/if it relaxes...
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