Blazer Marine Slingshot Build!

[Rene Berndt]

Hello Mario
I had the same problem. I take a heat gun a warm up the cowl carefully. Then mounting on the hull and let it cool down.

 

[Mario Johnston]

^Actually, I tried that first but only got so far before I noticed a wrinkle in the fiberglass near the exhaust. Decided not to push my luck.
There was still too much of a gap for the magnets to manage by themselves after this. This was before and after heat gun treatment.


Managed to wrap it up last night, I'm pleased with the snug fit!

 

[Mario Johnston]

I can live with that!

 

[user 21992]

Hi Mario, had the pleasure of building a SlingShot for RC Painter here on the Dock last month. I to, had that gap !!! and decided to leave the gap for the simple reason of air flow exit ?? Very little air flow going into the cowl area and will make the engine run a little hotter. Advised Larry, to add small air inlets to the front of the cowl at his decreson and definitely slots or a 1" circle back of the cowl and behind the carburetor (carbs like air). Your SlingShot is looking awesome, Good Luck !!

 

[Mario Johnston]

Thanks, John. Im planning on adding ventilation as well. Currently just getting the fit right. But i haven't forgotten to let it breathe!

 

[XtremeRcBoats]

Looks great Mario, don't forget to add some extra insulation around the spark plug wire, otherwise the cowl will cut right through it. I used a bit of teflon for it.

This is how i did it.

 

[johnsteltzer]

Looking really good

 

[Mario Johnston]

^Thanks so much, John!

Today's score, new (to me!) pipe for this monster of a motor. Time to make a mount!

(Thanks, Troy!)

 

[XtremeRcBoats]

I don't like having to drill holes for the mount in the rc compartment. This is how i did mine mount in CF. I can send you the dimensions if interested.

 

[Mario Johnston]

Grabbed some rare earth magnets from the local hobby joint. These little buggers ain't cheap, but a tube of these will let you do at least 3 or 4 boats.


Tonight's work, using a spare piece of cherry wood to make a cowl mount. Used a half inch drill bit to counter sink my holes.

Carbon strip will be epoxied into the cowl to hold this set up firm!

 

[Mario Johnston]

Thats enough for one night!
Next step, fiberglass this into place and finish the cowl's front lip

 

[Mario Johnston]

What a day! I owe a very special Thanks to Mike Ball for his help with this step.
I had been playing with some radio box concepts for some time after speaking with other slingshot builders about servo maintenance and (steering) push rod flex, So I began piecing together some new ideas for this build.
I loved the idea of a flex shaft mounted directly to the carb instead of a push rod and linkage,, so I sourced a throttle kit from ZippKits and got with Mike to work out new mount. Very pleased with how this came together!!
I sketched out the concept...

Mike took it a few steps further...

Completed 3D part

Add servo, cut carbon tie down...



Everything clears, nothing binds or touches radio box cover!

Marking final mount positions for glue after hull has been clear coated.

 

[Roger Lee Hooks Sr]

What would be a good prop for the boat with a Zenoah GZR-30 engine?

 

[Mario Johnston]

^Going to start with a CoCr CC3 and go from there. From my understanding this is a good all-around prop for this set up. But this big fast gasser business is all new to me!

 

[Mario Johnston]

Haven't put much work into the hull over the last couple of weeks, mostly due to work being very busy and other boats taking up my free time! Put a couple of hours into fiberglassing the magnet support and gluing the cowls front lip in place tonight

 

[Rich Jones]

This is a great thread Mario! I was in the club 20 years ago (has it been that long?). I used to race sport 40, 1/8 scale, and E Hydro. I’ve got all my nitro stuff in storage and haven’t thrown any of that to the wind yet but I’m going to build a Backlash over the winter. It’ll be my first build in a very long time and first gasser. Your thread is really inspiring! Really great technique all around! I look forward to getting back out and running with the club in the spring.

Cheers!

Rich

 

[Mario Johnston]

Thats awesome, Rich!
I'm so thrilled to hear from so many members about their appreciation for this build. I've met many seasoned boaters in person over the last year who have told me they've been following the progress. So thank you so much!

Break out some boats and start the prep for 2021! Although the club hasn't hosted a race for some time, we've been having a blast tearing around the lake chasing each other all year!! The Cincinnati club is growing again and I, for one, am certainly looking forward to meeting and driving with new (and old?!) faces again next season. See you out there, Rich!!

 

[Mario Johnston]

10 month update: technically the kit is finished... I've sort of been procrastinating because I'm incredibly nervous about the next step and fearful that I could ruin the entire project: I must seal the exterior soon so we can get her in the paint booth.
I've spoken to at least a half dozen builders about this step and have gathered my materials, just taking a deep breath before I make the plunge. Updates coming soon!
Still hoping to have her in the water come spring 2021

 

[Mario Johnston]

So its been almost 2 months since I touched this thing, but 10 since I started. The goal is still to have her in the water for spring but im done building up my nerve to tackle the next step: sealing the exterior. I have my West epoxy ready to go, just pulling the engine, hardware, etc back out that I used to mock up fits. Updates on sealing coming this week.


Also, on a side note:
Despite the uncertainty surrounding the coronavirus pandemic, I've been extremely fortunate to meet many I.W. members in person this year at events. For the guys who have come up to me to tell me in person you've been following this build, I offer a heartfelt Thank You.
Building this boat has been a fantastic learning experience and I'm thrilled to understand more about the workings of this hull via building it entirely by myself. I never expected to meet anyone who'd be as interested in watching it come together or anyone who would be inspired to build after following this thread. So thanks so much to all of you who are along for the ride with me as this is hugely encouraging for me as well, a new builder.
See you guys when we seal!!

 

[Mario Johnston]

And we're back!!!
Hardware and motor are back out of the tub, just finished giving the entire exterior a once over with 220 til it was butter smooth.
Tomorrow we hit it with the first coat of sealing.