georgec02

Hi all,

Complete Newbie here who's sheltering in place in CA. I've been working on some plastic model kits with my middle schoolers, but just ordered the Dumas Li'l Swamp Buggy. I thought it might be a good project as we're pretty home-bound right now. Apparently I can't post links as a new user. So, here's a description of what I've researched:

I'm reaching out for some advice as I try to understand

• What motor and associated electronics I might need
• What other accessories I'll need to complete (e.g. linkages, propeller, etc...)

Here's the description from the manufacture:
I know the Cox .049 engines aren't made anymore, and also thought it might be easier to do an electric conversion on this one.

Question regarding the engine:
I've been reading up on gas to electric conversion, as well as looking up other conversions on the same model. Having a hard time understanding what I should be using.

• I found a youtube video hereof a person that used a Park E-Flite 370 Outrunner which looks like it's 125W and is ~$40
• I also found another post here in these forums that used an Integy 300W Outrunner (which shows 30A 1000kv?) which looks like it also includes the ESC for ~$40
• Finally, there was a post that looked like the person used a Turnigy D2826-6 2200kv which looks like it's over 300W

From what I read, there's a combination of motor + ESC + battery, but I'm a little over my head. I don't need a ton of power, just enough to go a reasonable speed and for my kids to have some fun. Also, it looks like most people are using Lipo, which I know has more power to weight. However, my daughter has an RC truck with Venom 7.2V, 3000mAh NiMh 6 cell batteries. Can I use those and avoid buy a new set of batteries and charger?

Also, I'm not certain what type of propeller I should be getting. The kit is a push configuration.

• Can I get any propeller, but just reverse the direction / have the front face forward?
• How do I choose the right size propeller, and should it be 2 blade vs 3?

Question regrind ESC and Controller:

• For the ESC, it looks like I need to match to the motor and battery type?
• When I get a controller, can any of the receivers all hook up to any ESC or do I need to match those as well?
• Finally, do I get something that is a marine/boat ESC or airplane? or does it not matter?

Servo etc:

• Any recommendations on a servo for this thing? I've read that smaller is better for the size swamp buggy.
• Also, what kind of linkages would folks recommend? I randomly ordered the following. Are these usable for this kit?
  • Dubro Control Horns
  • Blade Linkage / Pushrod Set

Finally, is there a way to waterproof the electronics or buy waterproof ones in case the radio compartment leaks? and is an electric engine toast if it get submerged or very wet?

Thanks in advance for help with my questions. Hope I'm on the right track. Otherwise, this will be a nice display model.

Airboat68

I too am a noob but I had one of these when I was kid and I'm planning to do something similar from the ground up.

The cox engines can be found on auction sites but they are kind of messy. The battery and motor technology today is worlds better than it was 40 years ago so electric makes sense now.

As a newbie I can answer some of your questions:

• The prop should be a pusher prop and 6" is what most people choose. If you use a pulling prop you have to mount the motor pointing forward.
• A basic servo is all you need.
• The push rod is pretty basic. You can buy one or make one. Mine from years ago, was a bike shifter cable and it worked fine.
• Still learning about ESCs and motors. If your motor is brushless or brushed the ESC has to match. If your kid's RC truck is available to use, you could probably use all of its electronics including the motor and servo.

Got RPM

I have built a bunch of airboats and once built the Lil Swamp Buggy. You'll not be happy if he tries to use the Cox engines, cranky to use, messy and not nearly as safe as the BL systems. I'll try to answer the questions based on experience, not guesses.

Can I use those and avoid buy a new set of batteries and charger? Yes, although the weight will be higher they will work - If you can get them to fit.

For the ESC, it looks like I need to match to the motor and battery type? Yes, you do. For your 7.4 volt battery, the Park E-Flite and Integy 300W Outrunner are pretty low power systems and speed will be low - but probably still fun. They require 7" to 9" 2-bladed props for any kind of performance. The Turnigy motor will give higher performance, but draw more amps and require a stronger ESC. Not knowing the OP's budget it is very tough to make recommendations. But to match the original boat's performance, I'd recommend a 370 to 400 size outrunner with a Kv between 1500 and 2000. The ESC should be capable of a minimum of 40 amps. The prop will depend on the motor Kv, the higher the Kv the smaller the prop, but you'll still need one between 7" to 8" in a 2-blade, or 5" to 6" in a 3-blade. With more guidance I can give more specific recommendations.

Can I get any propeller, but just reverse the direction / have the front face forward? Yes, just be certain to have the motor turning the correct way.

When I get a controller, can any of the receivers all hook up to any ESC or do I need to match those as well? Yes, any modern 2.4 gig radio will work.

Finally, do I get something that is a marine/boat ESC or airplane? or does it not matter? Yes and no. The marine version is water resistant and will use water cooling. This complicates the build but can increase ESC reliability. The airplane ESC will work but needs to have a higher rating to handle the heat in the sealed boat.

Any recommendations on a servo for this thing? I've read that smaller is better for the size swamp buggy. While a standard servo will work, since you'll be using a large battery and space may be at a premium a mini servo may be a good idea. A minimum of 25 oz-in is recommended.

Also, what kind of linkages would folks recommend? DuBro aircraft control horns, clevises and golden rod is recommended, small size.

Finally, is there a way to waterproof the electronics or buy waterproof ones in case the radio compartment leaks? and is an electric engine toast if it get submerged or very wet? . Don't use screws to hold the hatch on, use electrical tape (available in many different colors). It works up to 100 mph (the fastest I've personally used it). Place a folded up paper towel in the hull to soak up any small seepage - it won't work for big leaks! The exposed motor can be fully submerged - it will run underwater - but dry it out as soon as practical by running it or using a hair dryer.

Keep us in the loop on your build!


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