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1/8th Scale Hydro Build

Discussion in 'Boat Build Projects' started by Tombsy, Feb 7, 2014.

  1. Tombsy

    Tombsy Boat Racing Fanatic
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    My Sport hydro build is waiting for some warmer weather to finish the paint and put it together but I think I've decided on a scale hydro to build for the 2015 race season. There are a couple other guys building them as well so we should be able to run in their own class.
    I'll start ordering the parts when I get back from vacation in a couple weeks.
    This is the boat the 1982 Executone. I picked this boat after advice from Mike at ML Boatworks who makes amazing laser-cut hydro kits, it's an easy build (relatively) no exposed dummy motors or wings to get damaged and lots of room inside for batteries. The kit builds the #8255 hull which was used by a dozen or so teams over a few years. RC Boatworks has a fiberglass cowl to fit this hull as well.
    Planning on a 10s setup with a Neu 1527 and Castle 240HV esc. It seems to be the standard setup for 1/8 scales.

    [​IMG]

    Here's the kit
    1/8th Scale Newton 138/ MHR 8255 [Newton 138/ MHR 8255-1/8th] - $135.00 : ML Boatworks, Laser cut rc boat kits
    I'll probably get most of the hardware from Accu-Tech, the graphics from Thunderboat Graphics, and the motor and esc from Offshore Electrics.
    Here's the cowl RCBoatCompany 1/8th scale rc boat cowling part# SG620C
    This will probably be the longest build in sparks history ;) but stay tuned for updates.
     
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  2. MrRcFanatik

    MrRcFanatik Studio Forums Elite
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    Very nice [MENTION=1109]Tombsy[/MENTION] ! Sweet looking boat!
     
  3. Tombsy

    Tombsy Boat Racing Fanatic
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    Made it back from slaying bonefish in Cuba, what a blast.
    I ordered the kit and everything else except the motor, waiting for an 8mm shaft to come in for the Neu 1527 1.5Y.
    The 1.5Y is 850kv that should be 31,450 rpm unloaded on 10s and that's in the right range 30,000 to 35,000.
    Volts x KV = RPM in case anyone wants to figure it out.
    The esc, some hardware, and batteries have made it so far. The batteries are a pair of Revolectrix 5s 60c 5200's and a pair of 5s 70c 5500's to be hooked in series.
    Not sure if anyone is interested in the details of the hardware but I'll list it anyway to keep track for myself.

    Rudder- Speedmaster 60 size dual pickup 1 5/8" setback
    Strut- Speedmaster SPSDS-Lrg. .250 Strut Hydro Flat-bottom
    I'm using a 1/4" flexshaft that tapers to 3/16" at the stubshaft.

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    The kit and the cowl are on their way.
     
  4. Tombsy

    Tombsy Boat Racing Fanatic
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    My kit for the boat arrived today, some assembly required but my driver is waiting patiently.
    The kit looks great, everything is beautifully cut with a laser CNC.

    [​IMG]
     
    #4 Tombsy, Mar 12, 2014
    Last edited: Mar 12, 2014
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  5. Tombsy

    Tombsy Boat Racing Fanatic
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    Racing season is over so time to get serious about this build, I almost chickened out on it and let my buddy frame it up for me but I'm going to give it an honest try. I've never skinned a boat this big before and I see how some guys take years to build these things.
    But it's on the jig all squared up ready to start epoxing it together. Rare earth magnets from Lee Valley help keep things lined up.
    All the joints will need fillets with thickened epoxy. I'm using West Systems 105 resin with 205 fast hardener and 405 filleting blend.

    I ordered a different motor, a Neu 2230, it's a real beast that's more than twice as heavy (and twice expensive) as the 1527, I'm hoping I can fit it in with my Swordfish 300 esc and two 5000mah 10s packs in parallel for a 10s2p config.
    Neu Motor 2230, Neu Brushless Motors | Rc Boats by OffshoreElectrics

    That's over 9 lbs. for just the motor, esc, and batteries. holy cr#p.

    This thing is going to have to be build like a tank, with the speed that these 10s boats run it totally pounds the heck out of the hulls.
    It will get carbon fiber inside the tub and sponsons for sure.
    Now I have to find another hull for an 8s build for my other motor, a fiberglass one this time. :)

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  6. Tombsy

    Tombsy Boat Racing Fanatic
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    My 10s packs arrived, looks like they will fit nicely.

    [​IMG]
     
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  7. Tombsy

    Tombsy Boat Racing Fanatic
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    Another 1/8th scale

    I just bought a fiberglass kit from a friend that was going to build an electric, not sure if it will be better for nitro or electric have to wait and see the room inside.
    So another big big build that will take a long long time but I think I'm going to make it the 2009 Hoss Mortgage.



    SG121H_RC_Boat_Company_T-6.jpg


    SG121H_RCBoatCompany.com_parts.jpg



    DBZ_7884.jpg


    2009_U-37_Hoss_Mortgage_Investors_Columbia_Cup.jpg
     
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  8. Tombsy

    Tombsy Boat Racing Fanatic
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    My buddy delivered the RC Boatworks hull, it's a pretty nice kit and I think it will be nitro powered but this project will have to go on the back burner until probably next winter, I'll be lucky to get this wood built finished this winter. But there has been progress, I reinforced the joints with epoxy fillets and I have started sheeting the bottom. I cut out a piece of 1/4" aluminum for a mounting plate for the turnfin that will get drilled and tapped for the mount.

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    I loaded up my epoxy supplies in a cart to make it easier to use and to bring in the house if the garage gets to chilly.

    [​IMG]
     
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  9. Antho11

    Antho11 Studio Forums Elite
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    Looks like a lot of hard work. It's going to pay of when your ripping up the lake! Wow! Two 10s lipos that boat is going to fly!
     
  10. Tombsy

    Tombsy Boat Racing Fanatic
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    I guess I lost a couple posts with the forum reset. The turnfin mount is installed with a 1/4" aluminum backing plate.
    I made a box to flush mount the servo in the side of the tub.

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  11. Tombsy

    Tombsy Boat Racing Fanatic
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    Working on the motor mount, with the cowl offset the mount can only be 3" wide to get the motor on the centre line of the boat.
    Been working on the rudder and strut mount, some CF reinforcing for the strut and a waterproof bulkhead instead of trying to seal the strut to be waterproof.
    The small ring is a fitting for the waterlines to pass thru the transom.

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  12. Tombsy

    Tombsy Boat Racing Fanatic
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    Some success with the motor mount, now to drill and tap some 1/4" aluminum backer plates for the side mounts and epoxy them in.
    The pencil line is the centre line of the boat, you can see how the cockpit is offset.

    [​IMG]
     
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  13. Tombsy

    Tombsy Boat Racing Fanatic
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    Change of plan with the motor mount, instead of mounting the side rail with screws thru the bottom, I made a new side rail from some angle, and now I can epoxy in a piece of 1/4" ply with some stainless blind nuts.

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  14. Tombsy

    Tombsy Boat Racing Fanatic
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    Time to get back to work on this boat, there are two other 1/8 scales in Calgary now and we need at least three boats to make a class. So the pressures on to get this done for next season. I got sidetracked last winter, I was rigging my Hobie fishing kayak and it took up half my shop.
    Today I epoxied in some CF cloth to reinforce the bottom and I have most of the sheeting laid out on plywood ready to cut out.
    Supposed to look like this when it's done
    IMG_0365.JPG
    .
     
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  15. RustyWrench

    RustyWrench ...I Always Edit...
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    Looking good. I can't believe I completely missed this thread.
     
  16. Tombsy

    Tombsy Boat Racing Fanatic
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    This one's been on the shelf for a bit, the fiberglass hull earlier in the post the guy I bought it from actually bought it back from me lol.
    I started another wood build of a new ML Boatworks Sport 40 size nitro boat so I was sidetracked with that for awhile too its about as far along as this one. It's a pretty new kit so I had to design the radio box and interior layout so it took awhile to figure out.
    [​IMG]
    I had a radio incident last year with my AC Sport 40 and kissed the rocks but I managed to get it patched up okay.
    I've got a Insane FE mono hull to put together to replace the Revolt so I think I've got more than enough to keep me busy this winter. Been trying to get some fly tying done too lol.
     
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  17. drzoo2

    drzoo2 Studio Forums Elite
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    Good to see you back at building. I remember it being a staple of the old RC Sparks and I missed those posts. I enjoy seeing real craftsmanship from someone doing things the rest of us could only wish we were able to accomplish.
     
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  18. Tombsy

    Tombsy Boat Racing Fanatic
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    Plugging away, got the bottom sides cutout and sealed with epoxy. Kind of awkward clamping, the other side will be worse. It takes a while to wait for each batch of epoxy to dry can pretty much only do one step a day.
    While I'm waiting for epoxy to dry I thought I'd share some of the materials I use, it's the same methods used on full size boats. IMO West Systems epoxy is the best stuff out there, the pumps make it easy to meter out each part. 105 is general purpose resin for wetting out wood, fabric and bonding. 107 is special clear for clear finish coating on wood or fabric. The additives are used to thicken it up for bonding, fairing, and filleting. Filleting is reinforcing the inside corner of a joint adding a bridge that adds strength. Fairing is like body filler the additive make it easier to sand. The carbon fibre fabric is 2k twill and the strips in different sizes with sewn edges are pretty handy. I give the backside of the fabric a really light spray of 3m adhesive and it makes it way easier to handle and cut.

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  19. Antho11

    Antho11 Studio Forums Elite
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    It's truly an art how you make the boats from scratch! I didn't know there was so much to epoxy!
     
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  20. Tombsy

    Tombsy Boat Racing Fanatic
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    Got some more sheeting and CF cloth done on the sides and put in the water exit and lines before the top sheet covers them up. Now back to the sponsons I've been avoiding :)


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