General discussions - FAST RC boat

LibertyMKiii

Aerodynamics speed junkie
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Curious if members do RC boats?

I struggle to do my RC car speed runs at only a few times per year due to the distance to a decent road. This will be even less now with my new build for 170+ speeds, which requires an airport ;)

I have a large lake 5 mins from home and looking to dabble in RC boats for the first time. As per my usual I want it fast, like REALLY FAST! 🔥
The plan is to run the XLX2 ESC (likely do a water cooling conversion) and TP4070 motor.

The fastest boats by far are outriggers / shrimp boats / lobster boats. The world record is held by the JAG team at 206 mph.
The plan was to mimic their design which is hand built (just my style :cool: )

Example of the JAG outrigger RC boat.
JAgCapture.JPG


When I had designed my RC car in CAD it took several months with so many moving parts all working together. I was shocked when I threw together my first draft of an RC outrigger boat within about 3-4 hours! It still needs additional work. I already have plans to adjust the front sponsons length and shape. All parts touching the water were designed with a 4 degree angle of attack and of course the motor and ESC are designed to spec for the size of the XLX2 and TP4070.
Battery position will be used to adjust weight bias. I read these run best with a 65/35 weight distribution.

Front quarter view.JPG



It looks like my 3d printer might be working the night shift again soon :)
 
Have you considered a design that lifts with hydrofoils? Less surface contact, less drag right? Oh, and prop dynamics are completely different. More aggressive props can push more water faster and shallower high speed props that may cavitate more. Hull size may also be permitting of a stupid powerful (watt rating) Neu motor with attached gearbox to alter rpm where a car chassis may not fit.
 
Have you considered a design that lifts with hydrofoils? Less surface contact, less drag right?
I have extensively actually.
It is something I would like to play with at some point.

The issue that I have not solved yet is that the hydrofoil creates lift that elevates the boat out of the water at specific speed ranges. At too high of a speed the boat will "pop up" and then dive under. You would basically need a way to control the amount of lift with flaps much like an airplane wing has. It would require a fast reacting microcontroller program to drive a servo for any level of real control. My reaction speed would be to late or over reacting I am sure.

The hope on this one is to reduce the center contact point using a center "ski" under the main hull of the boat.
Capture.JPG
 
I have extensively actually.
It is something I would like to play with at some point.

The issue that I have not solved yet is that the hydrofoil creates lift that elevates the boat out of the water at specific speed ranges. At too high of a speed the boat will "pop up" and then dive under. You would basically need a way to control the amount of lift with flaps much like an airplane wing has. It would require a fast reacting microcontroller program to drive a servo for any level of real control. My reaction speed would be to late or over reacting I am sure.
Possible channel mixing based on throttle position similar to some of the active spoilers available for speed cars? Basically a servo that turns the hydrofoil to change angle of attack, controlled by trigger position. Would definitely be tricky to implement, and the math would be super deep, with things like having to induce a timing or speed advance to pseudo-predict actual speed you are about to go as you throttle up.
 
Possible channel mixing based on throttle position similar to some of the active spoilers available for speed cars? Basically a servo that turns the hydrofoil to change angle of attack, controlled by trigger position. Would definitely be tricky to implement, and the math would be super deep, with things like having to induce a timing or speed advance to pseudo-predict actual speed you are about to go as you throttle up.
Yes and I think additionally it would need to be mixed with a gyro that feels for the boats overall AOA.
Maybe something for V2 of this adventure, but I do agree that sort of method would greatly improve speeds as water is 784 times more dense than air.
 
Just getting into boats myself started with something simple a proboat sonic wake.. I'm not out to break any records but can't resist a few mods. Had a TP 4050 1570 Kv lying around so in it went along with a Hobbywing 180 amp Seaking ESC and savox servo & Rc boat bits upgrade kit ( Turn fins. Trim tabs. Adjustable stinger. And Rudder) just waiting for a couple of props to arrive.

IMG_20210616_193746.jpg
 
Just getting into boats myself started with something simple a proboat sonic wake.. I'm not out to break any records but can't resist a few mods. Had a TP 4050 1570 Kv lying around so in it went along with a Hobbywing 180 amp Seaking ESC and savox servo & Rc boat bits upgrade kit ( Turn fins. Trim tabs. Adjustable stinger. And Rudder) just waiting for a couple of props to arrive.
Very nice!
I am thinking of a Deep-V boat for my son who wants to do some RC boating also. This sonic wake model made the list of possible options.
Thinking I may also need a kayak as a rescue vehicle should something go wrong.
 
Very nice!
I am thinking of a Deep-V boat for my son who wants to do some RC boating also. This sonic wake model made the list of possible options.
Thinking I may also need a kayak as a rescue vehicle should something go wrong.
How about a tugboat with an arm to corral any floating issues?
 
How about a tugboat with an arm to corral any floating issues?
The Kayak would sever as some much needed exercise also ;)
My wife and I have been talking about getting Kayaks or a Canoe for quite some time...
Both my boys like fishing also which would benefit from owning one.
 
Very nice!
I am thinking of a Deep-V boat for my son who wants to do some RC boating also. This sonic wake model made the list of possible options.
Thinking I may also need a kayak as a rescue vehicle should something go wrong.
A rescue boat is my next project. last time out a plastic bag got caught around the prop lucky for me some kids on paddleboards helped me out. the self-righting feature is very handy
 
I have a local lake that is a public park that I could use on off days. It’s pretty busy on weekends and holidays, but otherwise looks like glass. I own kayaks already and keep my rack on my Jeep just in case we find a reason to go out for a spin. I also live near about as much water as possible without having gills myself. I’m 10 miles from Lake Erie, about 45 mins from a friends lake home, and many many other local waterholes around me.
 
I have a local lake that is a public park that I could use on off days. It’s pretty busy on weekends and holidays, but otherwise looks like glass. I own kayaks already and keep my rack on my Jeep just in case we find a reason to go out for a spin. I also live near about as much water as possible without having gills myself. I’m 10 miles from Lake Erie, about 45 mins from a friends lake home, and many many other local waterholes around me.
Glass is slower than slight chop in the waves. Might be able to get a few guys out with RC boats to induce some roughness to the surface before a speedrun!
 
Just got into boats myself, Sonicwake perfect 1st boat.
20210127_152124.jpg

I gotta start on boats at some point, they look fun. I saw a 42 inch Horizon Hobby 8S catamaran on my LHS and I was very tempted to get it. Figured I'll do more research first though.
That was probably the new Blackjack 42.
Glass is slower than slight chop in the waves
That's true because a slight chop offers less drag.
 
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Glass is slower than slight chop in the waves. Might be able to get a few guys out with RC boats to induce some roughness to the surface before a speedrun!
Nice! Must be because the boat floats for a second in air.
 
Interesting story....

I found a listing on Dallas craigslist related to some RC boats from an estate sale. The guy was trying to sell lots of boats for a lump price of $700.00 Honestly was a great price, but I didn't have the budget to purchase it all. I messaged him about one catamaran I was most interested in and he said $35.00
Shocked at the price he mentioned I asked if I could come out yesterday evening. When I arrived he took me out to a trailer that was filled with RC boats. He explained that he was into RC planes and needed to get these out of his trailer ASAP. He told me that he didn't know if any of the motors worked as he acquired them from some sort of estate sale.

Image of what I was looking at in his enclosed trailer:
Trailer Capture.JPG


Long story short he really wanted this stuff gone and said for $150.00 take it all!!!!
Knowing this would make my wife very upset, I said sure you got a deal!

All are either a new hull that has not been setup, or was previously been setup for Nitro. The 2 smallest white and red boats have 3.5 outboard nitro motors mounted, but that is about it still requiring steering and other parts installed. Most do have props and rudders setup. The large white one measures in at 54" and is just massive.

The plan is to sell just about all of them except for the American flag pained catamaran and one of the deep-v boats that I'll setup for my son. Hoping that the sales are enough to equip the 2 we keep and possibly some left over $$$ to fund the car project further.

Here they are in my garage after returning home:
FleetCapture.JPG


Fleet 2Capture.JPG


Several motors were included. The large ones are Picco 67
There was also 3 electric ESCs, but I don't think they can be used as they were only rated to 40a, and looked very cheap!

Very crazy and I am still shocked each time I walk out into the garage. I went from zero boats to 12 boats over night :ROFLMAO:
 
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Knowing this would make my wife very upset, I said sure you got a deal!
You are a baaaaad boy! :LOL:

I think the red and white one with the wing looks pretty good. The big white one would cost too much to ship, or I would think about it. I could use it in the pool for my cat to sunbathe on. :ROFLMAO: I'm not kidding my cat loves water, I think he would like it. He keeps diving in the shower when I get in. 🤪
 
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