In the bold, I don't completely understand. I know the no trip piece but I'm confused where you add lots of epoxy to the sponson sheer plate???
Where the top edge of the no trip side sheeting meets the sheer. I want to soak as much epoxy in this seam as possible. Once this dries, much of the no trip top edge sheeting gets ground away shaping the rounded section. The attached photo shows this joint well. 1111.jpg
Bob Zola NAMBA 212 2022 NAMBA Nationals FE High Points Champion
Owner www.mojoracingproducts.comTeam Driver: Black Pearl Hydroplanes
Inner sponson bottom skin installation:
The long narrow stips are mounted to the frames. I pre bent these by hand. No heat was required, just marked area with pencil and tweaked the wood. I applied epoxy to the stringers and frames under these skins. I used a screw to retain the front and a couple of clamps held the rest. 33870.jpg33871.jpg
Bob Zola NAMBA 212 2022 NAMBA Nationals FE High Points Champion
Owner www.mojoracingproducts.comTeam Driver: Black Pearl Hydroplanes
There are 3 flat pieces that cover the bottom of the sponsons. For the rear ride pad, I varied from the kit parts with a carbon fiber piece. Same dimensions as the supplied wood part. Install the rear ride pad 1st. The front of the pad butts up to the notch or "Step". The 2nd photo shows the step. The rear will hang over the back of the rear sponson bulkhead about 1/8th of an inch. Glue with epoxy. Make sure this ride pad fits perfectly flat to the frames! 33872.jpg33877.jpg33874.jpg
Bob Zola NAMBA 212 2022 NAMBA Nationals FE High Points Champion
Owner www.mojoracingproducts.comTeam Driver: Black Pearl Hydroplanes
The center or 2nd "shingle goes on next. This part is the same dimension as rears. I am using the kits plywood piece for this. Apply the same as the rear. Butt the front edge up to the notch. The rear will hang over the pad behind it. This gives the shingled roof look. The front piece is a bit long. I fitted the part to the sponson and marked it to the tip of the sponson sheer. I cut off some of the excess material before I installed it. Use plenty of epoxy around the tip. I put a screw in the tip to hold this end down tightly to the sponson sheer plate. This are will be ground and shaped after the epoxy dries.
Where the top edge of the no trip side sheeting meets the sheer. I want to soak as much epoxy in this seam as possible. Once this dries, much of the no trip top edge sheeting gets ground away shaping the rounded section. The attached photo shows this joint well. 1111.jpg
Gotcha! Thanks. I added extra wood on the inside and sanded it down to the profile on my GRX310. I'm going to add a few piece of FG cloth etc.. like you have shown.
Awesome Bob. I can now run over more of your boats with confidence yours will survive, mine, well, time will tell....lol...
Gotcha! Thanks. I added extra wood on the inside and sanded it down to the profile on my GRX310. I'm going to add a few piece of FG cloth etc.. like you have shown.
Awesome Bob. I can now run over more of your boats with confidence yours will survive, mine, well, time will tell....lol...
My Q sport you ran over at 70MPH survived pretty well due to the cloth on the joints and energy absorbing foam packed inside the frames.
Bob Zola NAMBA 212 2022 NAMBA Nationals FE High Points Champion
Owner www.mojoracingproducts.comTeam Driver: Black Pearl Hydroplanes
Finishing up the sponson bottoms:
Used the GP sanding block with some fresh 80 grit self adhesive sand paper. Ground the inside edge of the ride pads and bottom sheeting flush. I also finish sanded the back of the sponsons to clean up some sloppy epoxy. Use a scrap piece of wood the right width to get into this tight spot. Stick on some sand paper and you have a nice way to sand in these tight spots. Sand the outer edge of the bottom sheeting flush to the no trip sides. Fresh 80 grit made quick work on this step. Finally, shape the front of the sponson tips bottom side. DSCN0429.jpgDSCN0431.jpgDSCN0430.jpgDSCN0432.jpg
Bob Zola NAMBA 212 2022 NAMBA Nationals FE High Points Champion
Owner www.mojoracingproducts.comTeam Driver: Black Pearl Hydroplanes
I applied cloth strips to all the bottom sheeting to stringer and bulkhead joints. After the strips were in place I put brushed another coat of West System over them. To make sure the top of the sponson side sheeting stays put, I reinforced the inside of the joint. Using a bent epoxy brush, coat with epoxy. I then packed some strips of fiberglass cloth up into this tight spot.
Installed some 1/4" plywood that the servo and motor mounts will sit on. I put some more cloth tabs on the center section joints. I also added some balsa and 1/4" sticks to stiffen the bottom pan where the batteries will mount. The balsa was capped with 1/64th plywood to level things out. These items will tie into the stringers and make the bottom pan stiffer. I also scored a NEU 1521 motor on the forum today to power this boat.
Deck it out:
Installed the top deck. Pretty easy process. Coat your top edges with epoxy and place clamps and some weights. I used a couple of 6S 6000mAh bricks and a big TP Power motor! The part laid down quite nicely.74.jpg75.jpg
Bob Zola NAMBA 212 2022 NAMBA Nationals FE High Points Champion
Owner www.mojoracingproducts.comTeam Driver: Black Pearl Hydroplanes
Hardware backers:
I hate blind nuts! I do travel races from time to time, and need to remove hardware for shipping. I have found blind nuts always strip out or fall off eventually! Working with washers and nuts in the tight confines of boats is a pain too. For this build I am using 1/8' aluminum plate material. These pieces will be drilled with a #29 drill and tapped with #6x32 threads. The back side of the plates have been scuffed up with 36 grit sander. This is to help the epoxy stick. Once the plates are ready to install, I cover the back side with epoxy. Coat your bolts with some grease and tighten the plate to the hull while the glue dries. 001.jpg0002.jpg
Bob Zola NAMBA 212 2022 NAMBA Nationals FE High Points Champion
Owner www.mojoracingproducts.comTeam Driver: Black Pearl Hydroplanes
Hardware backers:
I hate blind nuts! I do travel races from time to time, and need to remove hardware for shipping. I have found blind nuts always strip out or fall off eventually! Working with washers and nuts in the tight confines of boats is a pain too. For this build I am using 1/8' aluminum plate material. These pieces will be drilled with a #29 drill and tapped with #6x32 threads. The back side of the plates have been scuffed up with 36 grit sander. This is to help the epoxy stick. Once the plates are ready to install, I cover the back side with epoxy. Coat your bolts with some grease and tighten the plate to the hull while the glue dries. 001.jpg0002.jpg
The other nice thing about backing plates and starting out with 6- 32 screws is:
If a 6-32 strips out the hole left in the plate is the exact size for a 8-32 tap.
The same is for a 8-32 striped hole it is now the correct size for a 10-32 tap
Here is a tool that carry in my tool box.
It is called an Electrician's Tap (because these are the only screw sizes that they use). It is a stepped tap 6-32 - 8-32 - 10-32
Larry
Past NAMBA- P Mono -1 Mile Race Record holder
Past NAMBA- P Sport -1 Mile Race Record holder
Bump & Grind Racing Props -We Like Em Smooth & Wet
Get your 3/8" wood dowel rod and cut 2 pieces 9.75" long. This will leave a bit hanging out of each side and can be trimmed off later. Before installing the rods, I used the sanding block to smooth out the sponson to center section interfaces. Make sure both the center and sponson side surfaces are nice and smooth so you get a tight fit. Now your ready to install the dowels.
I slid these into position, just lightly offset. I brushed on some epoxy on the areas that will slide through the holes in the components. Rotate and center your dowel rods into position.
Before gluing I test fit each sponson making sure everything lined up flush. Then I coated the center section sides with a heavy coat of epoxy. Once coated you can slide the sponsons onto the dowels. I used some more servo screws to fasten everything down tight! Go around all the joints and brush with epoxy. I had to use a bar clamp as shown to pull the rear of the LH sponson in tight on the bottom seam. Now it's looking like a boat! 76.jpg77.jpg78.jpg79.jpg
Bob Zola NAMBA 212 2022 NAMBA Nationals FE High Points Champion
Owner www.mojoracingproducts.comTeam Driver: Black Pearl Hydroplanes
I drill and tap after gluing without the top skin on in case it screws up, lol... Might drill one tonight...
Originally Posted by mojoracer
Hardware backers:
I hate blind nuts! I do travel races from time to time, and need to remove hardware for shipping. I have found blind nuts always strip out or fall off eventually! Working with washers and nuts in the tight confines of boats is a pain too. For this build I am using 1/8' aluminum plate material. These pieces will be drilled with a #29 drill and tapped with #6x32 threads. The back side of the plates have been scuffed up with 36 grit sander. This is to help the epoxy stick. Once the plates are ready to install, I cover the back side with epoxy. Coat your bolts with some grease and tighten the plate to the hull while the glue dries. 001.jpg0002.jpg
Did some metal work at lunch time. Backers drilled and tapped, and a custom skid fin bracket fabed and welded. Drilled some holes in the hull and mounted these backing plates with epoxy. I use made in USA Speedmaster hardware on all my boats! Great products from some nice people in Florida. I'm using a .21 flat bottomed hydro strut and a 21 rudder. For the turn fin I will be using a Mojo Racing Products 40 size SS fin. 80.jpg81.jpg82.jpg83.jpg84.jpg
Last edited by mojoracer; 04-13-2018 at 08:07 AM.
Bob Zola NAMBA 212 2022 NAMBA Nationals FE High Points Champion
Owner www.mojoracingproducts.comTeam Driver: Black Pearl Hydroplanes
Getting ready for the deck!
Before installing the top deck, pack the inside cavities of the sponsons with some flotation. I used an old Styrofoam ceiling tile. 1 tile will do many boats! Pack it in tight. It also helps absorb energy in collisions! 85.jpg
Bob Zola NAMBA 212 2022 NAMBA Nationals FE High Points Champion
Owner www.mojoracingproducts.comTeam Driver: Black Pearl Hydroplanes
Installing the sponson decks:
Make sure all of your top frames are free of any epoxy lumps from the build process. I sanded all the top deck contact areas before decking. I test fitted each deck and drilled my screw holes before gluing. This way every thing will be lined up before epoxy coating!
Make sure to coat the inside deck surface with a good coat of epoxy. Also apply a liberal coat of epoxy to the frames the deck sits on. Once epoxy is applied, I placed the decks on and ran the screws down. Everything pulled down nicely. I only had to use 2 clamps at the rear of the decks to close the gap at the rear outer edges.
I flipped the boat over and put some fiberglass cloth tabs on the portion where the deck meets the sponson heals or transoms. This is the curved area at the back of the decks. Not i put some heavy epoxy coat in the joint where the deck meets the sponson sheers. This area will be ground down quite a bit to make the finished bull nose shape! Having the hull upside down held the epoxy in the joint nicely! Let it dry over night! 86.jpg93.jpg94.jpg87.jpg92.jpg
Bob Zola NAMBA 212 2022 NAMBA Nationals FE High Points Champion
Owner www.mojoracingproducts.comTeam Driver: Black Pearl Hydroplanes
Trimming the sponson decks:
You now need to trim off the excess plywood from the sponson decking. I found a great Dremel tool for this. It's a carbide coated cut off wheel and it is quite an awesome tool to have. This thing cuts through plywood and fiberglass like butter! I picked this up at my favorite local hobby shop, Prop Shop Hobbies for $19. Well worth it!
I trimmed the outer perimeter with the carbide wheel, leaving about 1/16th of a inch to grind off with the sanding block. The rear curves needed to be trimmed back as well. I used a pencil to mark this curve, guiding it with the edge of my finger. Once everything is trimmed, I shaped the bull nose curve with the sanding block. Fresh 80 grit makes quick work of this process! I also ground the rear of the no trip sponson side flush with the sponson heel. Hand sand to finish your curve around the entire outer edge. 96.jpg97.jpg99.jpg100.jpg98.jpg
Bob Zola NAMBA 212 2022 NAMBA Nationals FE High Points Champion
Owner www.mojoracingproducts.comTeam Driver: Black Pearl Hydroplanes
Sealing the plywood:
I sanded and cleaned up the entire hull in preparation for this step. I used an electric leaf blower to blast all the dust out of the interior and exterior. I use Z-Poxy finishing resin for this step instead of West System. This stuf brushes out much better, and cost a lot less. I like using the higher density foam brushes to apply this. Foam brushes work well, and don't leave a bunch of bristles behind! I coated the hull inside and out and hung up to dry. 101.jpg102.jpg104.jpg
Bob Zola NAMBA 212 2022 NAMBA Nationals FE High Points Champion
Owner www.mojoracingproducts.comTeam Driver: Black Pearl Hydroplanes
Lay out time:
The motor I bought arrived today. Time to lay the components in and check CG. Had to package the 4S 4000 lipos sideways. Looks like the CG will be at the center of the fin. This generally works on all the sport hydros I have run over the years. 105.jpg106.jpg
Bob Zola NAMBA 212 2022 NAMBA Nationals FE High Points Champion
Owner www.mojoracingproducts.comTeam Driver: Black Pearl Hydroplanes
Finishing the hull. I used some stinky Bondo to fill all the imperfection and screw holes in. After that I sanded the hull with 220 grit sand paper. I applied a coat of of automotive catalyzed primer. Now the external wood is sealed up.
I also installed the ledges for the rear hatch to sit on. Motor mounts have been started and the boat will be rigged out tomorrow! Getting closer.... 107.jpg108.jpg109.jpg110.jpg
Bob Zola NAMBA 212 2022 NAMBA Nationals FE High Points Champion
Owner www.mojoracingproducts.comTeam Driver: Black Pearl Hydroplanes
Installing the front nose pieces:
Trim the 1/4 round and bull nose parts to the correct length. I left them a 1/6th long and sanded to fit. The bull nose is taller than the plate it mounts to. I cut about 1/8th of an inch off the bottom and re-shaped the curve a bit.
Attach using epoxy. I chose to use screws run into the center stringers. I also used plenty of resin on the inside joints so the hell will be sealed. Fiberglass cloth strips were also added inside. This was a step that should be done before the sponsons go on. I did it this way due to the later arrival of the rounded parts. This concludes the major wood working! 113.jpg
Bob Zola NAMBA 212 2022 NAMBA Nationals FE High Points Champion
Owner www.mojoracingproducts.comTeam Driver: Black Pearl Hydroplanes
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