Hello, RC Noob here and I loved your video. Very informative and cleared up some of the areas I was fuzzy on with choosing the right ESC to match the battery. Lol I'll admit it, I had no real idea just how technical and specific the world of powering and controlling an RC boat is. I just wish I seen your video before I went to the RC hobby shop and started asking for things that I seen clearly made no sense to the guy I talked to. Lol I got a good beginner understanding of it all now. Thanks a million for making this video. I'm sure it's helping lots of people like me
*New Tinker* Hey, I just bought and crash my 1st boat on the same day. I'm currently researching ways to fix it. This video is VERY INFORMITIVE. You took me back to college electrical engineering class for a moment. At first, I was a little bord thinking this video wasn't a fun because it was showing you tinkering with a boat. The more I listened, I realized, you were giving us the ENTIRE formula on creating our own boat. Now that I've been learning all the components and how affordable they are, I will definitely be back when I make my own boat. (After I fix my current one)
Excellent Video!.......RC boat's Professor.......Loved it.....Thank you so much for sharing your knowledge with us......you are the greatest......all the best! 👍😎👍
Hi, I am 14 years old and love building RC Boats from dumas. This video helped me SO MUCH to select the right motor. I will be running the motor you helped me select in a Dumas SK Daddle Too. Thank you so much for helping me and making it easy to do this.
Just a heads up, these calculations are for a surface driven prop. If your outside is submerged, you will want to use less RPM and a smaller prop than what the video shows.
I'm in the process of converting my vintage ( constructed in 1965 ) 38" hydroplane from nitro to electric. Thank goodness I found your video! I can now systematically and accurately determine the proper components for the electrical system, information that I could find nowhere else. I also fly and look forward to your future video on airplanes.
Thanks for this info. This video is pure gold for someone just getting into boats (having spent my whole life on planes) and trying to figure out the black art of speedboating!
Got it. The thing is to have an on board your model is a power analyzer. This fits in between the battery and the ESC connections giving a true value of what is going on in power consumption.
Really good video with lots of useful information. I remember looking for information about building RC boats a few years ago and it was really hard to get any. Especially when it comes to the propulsion setup. There is still a lot of trial and error that needs to be done, but with the formulas you can get a good starting point directly from the beginning.
You all prolly dont care at all but does anyone know a method to log back into an instagram account..? I was dumb forgot my account password. I would love any help you can give me
@Luca Raiden I really appreciate your reply. I found the site on google and Im trying it out now. I see it takes a while so I will reply here later with my results.
I played around and found out. 💥Thankfully, had spares on hand and no fires This is a great breakdown. I'm new to boats and found myself kind of just throwing parts at it from what other people have used, instead of taking a calculated approach. For example, I just upgraded from 3S to 4S and running a 70A ESC, but this formula shows that I need at least a 90A ESC to get the full potential out of 4S
Great in depth video. Clearly a lot of effort went into this one. It would also be great if you could follow up these type of video with the boat build to this spec and test it. Then maybe go through the data log, to prove it works in real life. Would also make for interesting content. 👍
Hey Lawrence, thanks for the comment. As like most of the videos I do, I'd love to make a practical example video with all the components. However, it all comes down to budget primarily for the content I'd be showing. I would have to buy quite a bit of stuff for just this one video. My RC lineup is always changing every year as I don't hold on to stuff that I no longer use.
I truly appreciate you for sharing your knowledge. Thank you so much for all that you do for radio controlled toys. I must admit am new in the field. More power to you.
Hi I’m trying to follow your calculations for a 21in hull and I’m getting 363.439 how many watts is that sorry for the dumb question I’m very new to this
This was so accurate and had to check when done with set up.The math was perfect down to the prop and first time I have not had heat issues to address when I finished my boat!Formulas make a great go to and a lot of time had to go into figuring these out👍Thanks for sharing the info and great videos!
Hey that’s a wonderful tutorial on this video, for the layman rc boater . Was on your Radio Control Info site and found it very helpful, just wished you had many more brushless motor manufacturers to compare some the perimeters . I run several Neu motors and SSS motors. I did not see anything on SSS motors at all. Update some of the ESC. Manufacturers too. Will like to see a tutorial on the 55+ inch boats too.
hello there, this was such an amazing video and i am currently using most of it's information and it's all working out perfectly. i wanted to just ask how did you come up with the equation at 4:02 that has to do with the power with respect to length in inches and why did you use inches . and thank you very much
Hi, OK so you want your boat to go really fast. How a oat a formula for those of us who are not speed obsessed. My boat is a cabin cruiser and I am more interested in achieving scale speed rather than racing. Thanks for the video. Cheers Alan
I keep referring back to this.. I got me a used Electric King of Shaves 34" and this almost doesnt apply for redoing the ESCs.. but at the same time I can still use the math here to make sure my system is going to be good for what I've got vs what should be in it. The E.K.O.S. runs 2 motors, 2 ESCs and separate batteries for each esc. I also have the "lack of budget" factor to add in to the equation but yet.. still gotta be fast enough to take out a couple traxxas boats and still keep that lead! Help me out if you can!
Good night, thank you for making such an informative segment. I'm currently putting together a twin brushless catamaran. I have 180A ESCs and 4092 SSSMotor 4pole motors, the Hull is 38" in Kevlar. I watched your segment on timing, I would like to say that I'm new to boating. Do you think I should reduce the timing from factory set 15.00°. Available reduced values are 11.25°, 7.50°, 3.75° and 0°. Once again thank you for patients, be safe and family.
Hello, thanks for the comment. I prefer to run a brushless motor on sensorless mode with variable timing controlled by the ESC. The settings are then ranging from low to high where I like to select low timing for this type of setup and try from there. If your only option is fixed timing at a specific amount of degrees I also would start low here and find out where your sweet spot would be from there.
@@RCexplained I believe that the intervals are fixed. Is going to 0° down from 15.00° going to negatively affect my 4092 4pole motors? I'm using Seaking 180A ESCs. I haven't scrutinized the manual in detail.
Great video. I love to see a mathematic equation being used to be informed for picking components. Just one problem. The equation says it’s good for boats up to 50” What if my set up is 72” what changes with the numbers to come up with a good set up for that? Why does it change at 50”?
I have a wooden model boat that I want to turn into an RC boat! It weighs 600g and is 60cm long and 18cm wide and already has a propeller with a diameter of 43mm. It has a v hull. I want the bot to be able to level but it doesn't have to go super fast. I want the bot to have a range of 30m and have a battery time of at least 15 minutes! Can anyone recommend some parts? I'm completely new to the hobby😅
40inch Catamaran built with 3mm plywood With dual 4092,1550kv,200a 6s 7000mah 60c per motor 12s of total What do you think about this setup and this is ok then suggest me good propeller
Great info for sure. To test the 🧠 I have a 51in v hull (gas to electric conversion) so one shaft and prop. For a one motor setup this will be crazy big motor/esc is expensive and the battery requirements 🤯 so I like to use two motors turning the same shaft. Should I just Divide my motor wattage results and run two smaller esc's an motors? Seams like I would have more options and tuning...thank's!
Wow that's a lot of information my brain hurts great video though. I think I'm going to find somebody with the same boat see what they're reliable bashing set up is and of course their temps and try that if not I'll go back to college and check out your video again
Good video! Easy to follow. I've tought that mine setup was around the same as yours but someone mentioned his props are always below the water surface and that messed up my mind and my calculations. So what to do when it's 31" v hull with two motors and a gear ratio of 3:1, the stock props are 45 mm. It's an old Graupner Portofino I'm building but I wanted to replace the old brushed motors (with in this setup had a top speed of 20 km/u) for more speed. Hope you can help me
This is a great video with very good information on how to get the correct power system for running electric with RC Boats! I've been on the nitro side of racing for years but I want to get into electric, I see the advantages! Can you explain more about how you "data log"?
Glad it was helpful! Some ESC's have data logging built in. In other cases you can buy a stand alone data log to gather information. If you are not using data logging, knowing the temperatures of all components is the next best option.
I am about to replace evetything in a big RC Yacht with a double Brushless setup that I intend to do with 2 ESCs. Also it is my fist contact with brushless on my own. You cannot imagine how much this video helps me to start. For the intended double motor setup, I have halved the overall Wattage that came from the hull length. If you have further advice for me about such a setup and its layout, I would welcome it.
Thanks for your comment, just keep in mind the formulas are for a surface driven prop. If you are running a fully submerged prop you will want to decrease the overall rpm by a significant amount.
@@RCexplained Thank you! Also it turned out that i am very restricted in the (fully dived) prop diameter, like 3,5 cm instead if the theoretical 4,4cm. Can you please tell how I should adjust my choice according to that? Should that make me reduce the RPM even more and that is all? Thanks four you answer in advance!
Did my "Super Thanks" donation and comment from July 18 get deleted or was there a misunderstanding? I'm completely new to RC anything and this is the most helpful source I've found.
Hey Ron, thank you for asking about this and Appreciate your "Super Thanks" !!! I don't see where it shows who and where it came from but it does show up under the super thanks category in monetary form. Perhaps the comment that you made did not go through some how? It doesn't look like I can see who it was from if there is no comment, however, I am quite new to this and yours is the first one! Thanks again!
@@RCexplained No problem, I was just saying that this and the radiocontrolinfo calcs are very valuable information and I followed along every step to make sure I was doing the correct thing for my boat. My boat is very similar to your example at 36". My question is in regard to the ESC selection. My boat uses 2x2s batteries or 3s, but many other owners of my boat have claimed they had to upgrade their stock 120amp ESC to a 150a or 180a ESC to run 6s, even after cooling mods, because they "fry" them. As I calculated your current selection at 9:33, it shows the current as smaller as the battery cells go up. So 6s would be 60a x 1.3 x 1.3 = 101.4 where 4s is higher at 88a x 1.3 x 1.3 = 148.7 current. Am I getting something wrong where going from 4s to 6s looks like it would require a smaller ESC? I'd like to do the right thing before throwing 6s in there. Thank you very much!
@@ronchang9791 6s in the boat is going to increase the current if you are not changing anything else in your power system. If you changed the prop out to a much smaller prop, you can reduce the current. In the example we can reduce current by moving to a lower Kv motor when selecting the motor Kv. You can also reduce current by swapping out your motor to a lower Kv. You can try doing a mock up system with both 4s and 6s and see the differences in the power system selection process. These differences allow wattage to be the same.
Can you help me configure my 2 bldm with controller. I made boat with 2x 1400kv bldm. Now I need to rotate one clock wise and other counterclockwise. But my problem is when I turn right I need to off one motor and when left need to turn off other. How can I do it with one stick. My transmitter model is FS-CT6B. Can you help me figure it out. ( pressing forward both motor rotate. Forward + right only one motor rotate. Forward + left only other motor rotate.) Thanks
Hello, first of all, thank you kindly for video - it really helps! I`d like to ask some questions regarding it. I`ve calculated amount of power I need for my boat (22 inches - approximately 400W) and I`m going to use two engines separately. Shoud I divide total power amount by two then and proceed with 200W? Thank you a lot, truly.
I bought a tfl zonda boat 2x motors 3674 2075 kv with 120amps esc so I bought 2x 6s lipos 5000mah 22.2v that should be able to have it,stock props and timing set on p? What you reckon?thank u
I have a 150lb boat mono hull, that I am trying to push along very slowly, maybe 2-3mph for a long period of time, meaning an hour or so. I am so confused on what the right combo would be. Will a small prop or big prop be best, will a 5400mah battery last for a while. Uggggg.
Super awesome. I am going to have to do some math. I’m 3D printing a Riva mono hull but it is supposed to be a dual prop. How does the math change if your using 2 props? I would like it to go fast but I’m a newbie and not looking to race etc. I would like to keep costs down just a fun project. I’m planning on using 2s Lipo batts. I can use single batt or 2 batts.
Great video as usual. I've got a couple of questions, as usual. I may have missed it somewhere, but how di you arrive at the 24-33000rpm with most motors have a 50-60000 range? Reliability, a power range I missed, or both. And for the cell count on the esc, most have a range. 2s-6s for example, or a 4s-8s that I'm looking at, would I be best off with matching themax, or in the middle. I am planning on 6s for my speed run car. I know the math will be different, but I'm trying to understand the overall picture here. Thanks!
Thank you Adam. The RPM range is the range that is best suitable for RC boats utilizing surface drive props. An ESC rated at 2-6s can work for 2-6 cell LiPo.
Thanks, I'm on the technical side, and when I hear "X", it's "X". I'm trying to figure out my speedrun build, and I'd like to get the numbers right, from the beginning. Everything else is to be setup based on my power system. I've been getting high wattage, voltage matched gear, and the kv for rpm just under the max rpm of the motor. Allways a little headroom, an I can't over rev. Am I in the ballpark in my thinking? With resistance and size, so forth from your other highly informative and engrossing videos, of course. Bad with math, good with spec numbers, with an electrical backround. I get what your saying, your great, but I lose some of the math. Sp I tru to get the concepts down, and take my time doing the math, once I've narrowed down the field. Thanks for the grest info!
Good morning and Merry Christmas to you and your family. I really enjoy your information videos, they have guided me over the last few years through nitro buggies, crawlers and boats and I want to simply say thank you. I really need your help. I got myself in a pickle. I purchased a catamaran Hull (38.5") and twin 4092 SSS 4pole 2140Kv motors, 180Amp ESCs Hobbywing V3 and 48mm 1.8 pitch 3 blade CNC props. I am not able to calculate my safety or ability of this setup. I have other props ( 17/16 2blade, 45/1.9 2blade and 40/1.9 2blade) that I can try out. I just wanted to go about 100mph +, but I may have bitten off more than I can chew. I only made that setup because TFL has it in a couple of their boats. Anything you can help me with is highly respected. God bless and Merry Christmas.
Kv is a bit higher then what I would prefer, even for straight away passes. Only 2 WOT passes and then bring the boat back in. You will want to start as small as possible on the prop and work your way up. The pitch on your props also seem very high. Do you have everything installed? Merry Christmas to you as well!
Also, does Kv have a different effect in relation to 4pole vs 6pole? Can you please, respecting your patience, help me to start understanding some of the science?
Hi Ryan, I'm conducting a thesis project on USV's and the vessel is of a similar size to an RC boat. I was wondering if you would be able to share how you derived your equations for power required based on hull length and prop size based on motor power? Thanks.
Hello Ben! hope you are doing good. I want to know what type of thesis project you have done on the USV and can we communicate on any other websites as I am also doing a thesis project on the same topic. I have some queries related to validation point of view, I would greatly appreciate your assistance towards me, and it would hold significant value. Thank you!
Hello! I want to know the constant that you have used in the first equation where you are calculating the power of the boat from where did you get that specific constants of 4.279 and etc? Is there any proof of concept behind it please explain or an website or research paper.
@@RCexplained can you elaborate a bit more, from where did you get the data set and which data analysis and statistics technique you have applied to get these values. I will appreciate your help.
How do you modify the propeller calculation for a submerged prop, as I presume taht the load is approximately doubled for both blades being in the water at the same time? Thank you for your insights, it should save me a load of money in failed experiments!!
You will have to modify the RPM range as well as the power range first. Overall a submerged prop will require less RPM. 10k-25k depending on the size of the hull. Power will depend on your speed goal. Size of prop will be reduced and will largely be based on your chosen RPM, motor and power potential.
Ok this video definitely helped answer a lot of my questions but I just picked up a boat for my kid and it’s already built but has no battery’s how to I figure out what batteries for it Catamaran hull 32” Ammo 36-50 3300kv Phoenix ice light 100 Prop is a 40mm
I'm not a fan of that motor selection that was included in your purchase. Typically a 32in boat would take 4s. But with such a high kv on a small motor, I would run 2s.
This is a great video, very informative. Is there a reason why hull weight is not a factor in these calculations? I am working on a conversion for a vintage hydroplane that is wooden, so significantly heavier than the modern hulls.
any suggestions if i want to use two motors (so i can have differential throttling for steering) for the 6ft long aircraft carrier I'm building? the I want ESC's with reverse as that might affect my motor power options to suit the esc amperage.
Just a heads up. The video is for surface driven props on fast electric boats. For fully submerged prop significantly reduce the amount of power and motor rpm as your targeted speed will be very low.
Great video. It is a starting point for me. I am currently building a 60" PT boat (1/16 scale). Question: The formula domain is for max hull length of 50". What do I need to change for my current build? Also still debating on 1, 2 or 3 motors depending $$$$
Great videos! Curious what your take is on underwater thruster designs. I am designing my own version of a T-200 thruster (pretty much underwater EDF) and am wondering if the same rules apply. Mind you this is gonna be a kayak assist motor so will never reach much speed so I wonder about the drag. Will have to play with prop pitch for sure.
@RCexplained understand that, that's why I ask your take on what the differences would be in calculating for a somewhat ducted outrunner thruster version
Great informative tutorial video! I do need your reply regarding my boat setup. Im using 3S 7600mah 70C x 2 Series connector at 4092 1700KV with 180A Seaking and tried with 40-42mm props but only manage to get 80km/hr on the Cataran 1040 total length. Did i go wrong anywhere on the setup? Can the boat reach 120-130km/hr with the correct props? Please advise... Thanks mate!
Hi Dayak, what is the temperature you are getting on the battery, ESC and motor? If you have room in temperature to go up, you can try slowly increase the size of the propeller. Getting to 120-130km/h may be tough as that is a big ask.
Your batteries are getting up there in temperature. Overall you can squeak a bit more power out of the system by going to a slightly larger prop. Keep an eye on temperatures and once you exceed a safe maximum you've reached your limit.
I am working on my first rc boat 36" long. The data you gave is apt. But i have already a 2650kv brushless motor and a 200a esc. Will a 4s 5000mah battery works well on this. Appreciate your suggestion. I find your videos educational. Thanks
Hi Boni, a 2650kv motor on 4s in a 36inch boat is going to be a tough combination to work well. It's not a setup I would recommend or suggest. The motor is going to require a smaller prop then what your boat may need.
@@RCexplained thanks. Ive changed my mind and go on two 3450kv with 50a esc brushless will be connected parallel to 6s 5400mah battery. My prop are 3 leaves 36mm 1.4pitch. I hope this will be a good set up. More power
Hi Boni, you are moving in the direction of more smoke coming out of your components. 3450kv on 22.2v is 76590RPM unloaded and would be far too much. What did the formula in the video say to use for kv, power and prop size? I would expect twin 36x74mm motors around ~1400kv using running 6s to be much better for you. You would need 80A ESC's.
Hi, I have a 40 inch mono hull. What setup should I be using? I tried to figure it out, but I ended up with huge C ratings, low kv and when I look at batteries and engines for sale I can't find anything that comes close to fitting....please help.
@@RCexplained well, I got a ~50cm prop...Im not looking for the max speed...just something fun, its my first rc boat. I was using the lowest rpm you had 22500 iirc. Any help? Thx for replying:)
Use a 40x92mm motor around 1000kv. 120A ESC rated for 6s LiPo. Use a 6s LiPo minimum 5000mAh 45C. Use a 48mm to start and work your way up from there checking heat frequently.
I learned a lot from your video. Question- how do I include the weight of the boat into your calculations. I have a 26 inch, wood, former nitro, tunnel hull. It is 5 pounds. This is much heavier than a comparable fiberglass boat. Right now, I seem underpowered. Appreciate the help.
@@RCexplained With my own guess- I currently have a 3650kv (600w nom) with a 90a ESC which called for a 2s battery and about a 42mm prop. The ESC kept stopping and overheating. After calculating using your system, and with a 26in wooden tunnel hull, I calculate a 1690kv with a 36mm prop and 4s. What do you think?
The required thrust would depend on the speed you plan to achieve and then your submarines hull shape and size drag. You would need enough thrust to match the drag created at speed.
This is a great video, but I am lost! lol. I have my sons 34" mono hull that I 3D printed. At first I just went with the specs the designer used which was a 3650 motor with 4200kv, 3S battery, 36mm prop and 150a ESC. We burned the motor out in 10 minutes. Not sure if this is just because it was a cheap piece of junk from Aliexpress or if it was just improperly sized. I think, based on the calculations I could follow, I am better of going with a 2450kv motor. Any chance you can confirm or deny that and maybe steer me in the right direction? Any help is greatly appreciated!
I'd go with a leopard 4074 to 4082 leopard motor with 4s LiPo and a Kv of around 1800 to 2000. If the ESC can do 4s you are good. Start with a 40mm prop and work your way up.
@@RCexplained I have been digging into the motor dimensions and the hull. WIthout changing out the motor mount (current one is also 3D printed from the hull designer), I dont know if a 40mm will fit. Am I still safe going with a 3650 on 3s? Would I want a similar KV or slightly larger kV? Or do I go with your recommendation and purchase a motor mount or design one of my own?
@@RCexplained Speed isnt a large concern of mine. It is a 3D printed boat for my 5 year old son. 30mph maybe should be plenty for him. My main concern would be keeping the diameter at 36mm so that I can still get a cooling jacket on and fit in the hull. It uses a straight solid shaft design, so the motor is low in the boat. If I had to go with a 74mm I could, I would just have to relocate the ESC. Not a huge deal there.
Hi there, Its awesome to see your knowledge in this area. Being new to this I had a bit of a hard time following everything you where speaking on. My son and I are building a 48” mono hall and I’m looking to get 25-30 mph out of it. I got the first calculation of 3900 watt/power but was lost on the rest. Any chance you could help me out so I can order what’s needed to complete the electrical set up. Thanks
@@RCexplained Thanks for getting back to me. I’m going to be running 5200mah 11.2 volt 3s. I know I could go way bigger but it not really about speed for me. I’m going with a 60amp esc and 3650 motor. The boat is going to be more for fishing (as I’m mounting a fishing reel and rod on it with a worm gearbox and secondary esc to run the reel) Any thoughts? Thanks
You could go 3s but you would need to be up around 100A minimum or so to have a chance at 30mph with a low drag hull. The motor will have to be at or less than 1600kv. 50mm prop. You would be better off with 6s minimum and an 800kv motor using a 50mm prop. 100A ESC. Minimum Motor size recommendation for either cell count is 40x82. Typical fast electric boats at this size are using 10-12s LiPo at 100A for 40mph and up. Your application is a bit unique. Keep RPM's on the very low side of the range.
This video is awesome. I'm working on an RC plane currently, but would most of this info work for that context too? My initial issue is finding the correct wattage required which is your first step here. What flight parameters drive that? Thanks!
RCexplained Unique design that has similar dimensions to a scaled down 747 and is also a pusher configuration. Wingspan of 6ft and target weight of around 17 lbs (including motor, batt, etc.). Let me know if you need any more info.
Thanks for sharing the video! Very educational! For a 50" mono-hull deep V boat for autonomous mission not tailored to be very fast which formulas should I get? Thank you
@@RCexplained Thanks for the quick reply. The boat is this one: ibb.co/bPt3SL9 Looking for no more than 20mph. It will be cruising around most of the time at slower speed
Link Doesn't seem to be working. If the boat will be travelling at slower speeds mostly, I would have the components selected specific to this vs hitting higher speeds closer to 20mph. You have options, you can run 6s LiPo on a large outrunner with a 60mm prop or so.
@@RCexplained Please try this link instead: drive.google.com/file/d/1ycz61qqw2JDgFh55scEQJhSE7pGiYVvE/view?usp=sharing Do you think that a 4084 620kv, 6s Lipo, with a 60mm prop (1.4 pitch ratio?) would be a good starting point?
@@RCexplained Please try this link instead: drive.google.com/file/d/1ycz61qqw2JDgFh55scEQJhSE7pGiYVvE/view?usp=sharing Do you think that a 4084 620kv, 6s Lipo, with a 60mm prop (1.4 pitch ratio?) would be a good starting point?
But what about the RC part? Do boats have controllers like quads to combine the inputs from radio into signals of the motors? There are 2 motor configuration, but all I've seen - the direct commands from radio to ESC
@@RCexplained I want to have telemetry "on FPV" (displayed current draw, component temperature etc), you've said in this video - send the boat to water, return home, measure temperature :) guys on quads & planes do not need to return the model to get all this info
Another quick question ,, can I use 80A brush less ESC and 4000kv brush less motor with 2to3s lipo and 33mm prop for my 23 inch RC catamaran boat that I have built ?
Getting a small boat up to 80km/h will be tough. If you want to use 3s LiPo you will have to use the lower kv. Preferably around 3000-32000 or so. You can use 3400 but you will have to monitor heat so nothing blows up.
Hey! Somehow I get the calculation on step three wrong ... it will be - 600 approximately. I have a 20 inch long boat and 8 inches wide if it matters and count exactly as you describe in the video. Do you know what I'm doing wrong? Just thinking that -600 watts can not be true. Sorry if my english isnt right, i used Google translate beacuse i an lazy but i hope you understand!
Hi Joel you can put it in excel or run it in an online math calculator. I also have a calculator within the download able spreadsheet on the patreon member site. You can can also drop the number here and I can try and help out.
Good morning 1) mono 2 competition 2) 80cm 3) 6S 22.2V 4) 6000mah 5) ESC 150 minimum 6) mandatory limiter, and transponder 7) 7 minutes of autonomy required for the race 8) minimum voltage after race 3.3v per element, otherwise disqualified. can you help me to design this mono 2
These equations are for a surface driven propeller. Does this match for you? On the radiocontrolinfo website, there are calculators to help determine and estimate. speed based on your calculation.
Hey I'm building a 23 inches catamaran RC boat ,, so can you please select the battery , watts of power and motor kV and size of the motor and ESC for me please ,, ,I'm a bit confused
I'm new for RC boats and building them so I really need your help in selecting the electronics for my 23 inch catamaran boat ,, I don't want to fail in it ,, 🙏
Great video. My English is not very good It’s possible that you recommend me what motor to get..?? I’m building a catamaran rc boat it’s 70\34 cm Thank you very much
Hi thank you The length is 27' inches I'm completely confused about what battery esc and motor to buy I'm not looking for a very fast boat Thank you for your help
I would just add a multiplier to the power calculation. Each motor is 80% (if looking for higher speed) or 70% (looking for a lower top speed) of the power that you calculate using the in video formula.
hi, greetings from México, I just made a fiberglass boat, is 32 " or 820 mm, the weight is 2.174 kg, my problem is that I have no idea about the engine and electronics, I made it for my grandson, can you help me to select all the items for my project?, I relly want to finish it any time soon; by the way, if you need it I'm a fiber glass specialist modeler.
A motor usually don't have a specification for the required ESC amerage. For unloaded RPM, you would have to calculate this based on the setup you are running.
Yes. I took it out with the stock 4519 props (2blade). I bashed for about 20 minutes between 50-60mph, the motors and ESCs were lukewarm. It took me about 2min to open the Hull to check. But so far no heat from the batteries. I have never done a high speed run yet. I'm in Canada so that means crawler season.
Thanks for sharing this info. What are your thoughts on the motor and ESC for a deep V hull 40" long with a jet drive? I have not picked a jet drive size yet either. Thanks
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Hello, RC Noob here and I loved your video. Very informative and cleared up some of the areas I was fuzzy on with choosing the right ESC to match the battery. Lol I'll admit it, I had no real idea just how technical and specific the world of powering and controlling an RC boat is. I just wish I seen your video before I went to the RC hobby shop and started asking for things that I seen clearly made no sense to the guy I talked to. Lol I got a good beginner understanding of it all now. Thanks a million for making this video. I'm sure it's helping lots of people like me
Thanks for the kind words
*New Tinker*
Hey, I just bought and crash my 1st boat on the same day. I'm currently researching ways to fix it. This video is VERY INFORMITIVE.
You took me back to college electrical engineering class for a moment. At first, I was a little bord thinking this video wasn't a fun because it was showing you tinkering with a boat. The more I listened, I realized, you were giving us the ENTIRE formula on creating our own boat. Now that I've been learning all the components and how affordable they are, I will definitely be back when I make my own boat. (After I fix my current one)
Excellent Video!.......RC boat's Professor.......Loved it.....Thank you so much for sharing your knowledge with us......you are the greatest......all the best! 👍😎👍
Hi, I am 14 years old and love building RC Boats from dumas. This video helped me SO MUCH to select the right motor. I will be running the motor you helped me select in a Dumas SK Daddle Too. Thank you so much for helping me and making it easy to do this.
Just a heads up, these calculations are for a surface driven prop. If your outside is submerged, you will want to use less RPM and a smaller prop than what the video shows.
This man is a guarantee for success on your project, you can set your watch to what he teaches.
Great video Ryan, have a nice day!
Thanks for the comment Eden!
Fantastic video! You have simplified deciding how to power a speed boat for optimum performance with a very clear, logical explanation. Thank you!
The best vedio for for RC boats! solved millions of my questions. As a beginer i am intersted on what each type of haul looks like
Hey Ted, thanks for the comment! Here is a look at the different hull types.
www.radiocontrolinfo.com/rc-electric-boats/boat-hull/
I'm in the process of converting my vintage ( constructed in 1965 ) 38" hydroplane from nitro to electric. Thank goodness I found your video! I can now systematically and accurately determine the proper components for the electrical system, information that I could find nowhere else. I also fly and look forward to your future video on airplanes.
Brilliant summary of proper drivetrain dimensioning !
thank you Jacques
Thanks for this info. This video is pure gold for someone just getting into boats (having spent my whole life on planes) and trying to figure out the black art of speedboating!
This is10s of hours of reseafch work in 30 minutes this is just amazing nice work
Amazing video, learnt so much form this methodical approach to planning. Keep up the great work!!!
Got it. The thing is to have an on board your model is a power analyzer. This fits in between the battery and the ESC connections giving a true value of what is going on in power consumption.
Brilliant. Been looking for this in this format for years. Well done
Really good video with lots of useful information. I remember looking for information about building RC boats a few years ago and it was really hard to get any. Especially when it comes to the propulsion setup. There is still a lot of trial and error that needs to be done, but with the formulas you can get a good starting point directly from the beginning.
Yes, for sure. There's limited information about RC boats. Thanks for the comment Razor Blade!
You all prolly dont care at all but does anyone know a method to log back into an instagram account..?
I was dumb forgot my account password. I would love any help you can give me
@Yusuf Raymond instablaster =)
@Luca Raiden I really appreciate your reply. I found the site on google and Im trying it out now.
I see it takes a while so I will reply here later with my results.
@Luca Raiden it did the trick and I actually got access to my account again. Im so happy!
Thanks so much you saved my ass !
I played around and found out. 💥Thankfully, had spares on hand and no fires This is a great breakdown. I'm new to boats and found myself kind of just throwing parts at it from what other people have used, instead of taking a calculated approach. For example, I just upgraded from 3S to 4S and running a 70A ESC, but this formula shows that I need at least a 90A ESC to get the full potential out of 4S
Great in depth video. Clearly a lot of effort went into this one. It would also be great if you could follow up these type of video with the boat build to this spec and test it. Then maybe go through the data log, to prove it works in real life.
Would also make for interesting content. 👍
Hey Lawrence, thanks for the comment. As like most of the videos I do, I'd love to make a practical example video with all the components. However, it all comes down to budget primarily for the content I'd be showing. I would have to buy quite a bit of stuff for just this one video. My RC lineup is always changing every year as I don't hold on to stuff that I no longer use.
I truly appreciate you for sharing your knowledge. Thank you so much for all that you do for radio controlled toys. I must admit am new in the field. More power to you.
Glad to help! Appreciate your comment!
Hi I’m trying to follow your calculations for a 21in hull and I’m getting 363.439 how many watts is that sorry for the dumb question I’m very new to this
Man I am working on a setup now and you just gave me some missing math👍Love the video and knowledge is power⚡️
Great to hear!
This was so accurate and had to check when done with set up.The math was perfect down to the prop and first time I have not had heat issues to address when I finished my boat!Formulas make a great go to and a lot of time had to go into figuring these out👍Thanks for sharing the info and great videos!
Hey Mild to Wild RC, thank you for sharing your experience. I'm glad the video was able to get you a good system for your boat!
Hey that’s a wonderful tutorial on this video, for the layman rc boater . Was on your Radio Control Info site and found it very helpful, just wished you had many more brushless motor manufacturers to compare some the perimeters . I run several Neu motors and SSS motors. I did not see anything on SSS motors at all. Update some of the ESC. Manufacturers too.
Will like to see a tutorial on the 55+ inch boats too.
hello there, this was such an amazing video and i am currently using most of it's information and it's all working out perfectly. i wanted to just ask how did you come up with the equation at 4:02 that has to do with the power with respect to length in inches and why did you use inches . and thank you very much
Very good video! Your explanation was clear and helpful. Big thanks!
Amazing video! What a awesome explanation!
Thanks Alex!
Awesome find.
Very informative, thank you.
Glad you enjoyed it
So super so needed
Very helpful, thank you
Glad it was helpful!
Hi, OK so you want your boat to go really fast. How a oat a formula for those of us who are not speed obsessed. My boat is a cabin cruiser and I am more interested in achieving scale speed rather than racing. Thanks for the video. Cheers Alan
I keep referring back to this.. I got me a used Electric King of Shaves 34" and this almost doesnt apply for redoing the ESCs.. but at the same time I can still use the math here to make sure my system is going to be good for what I've got vs what should be in it. The E.K.O.S. runs 2 motors, 2 ESCs and separate batteries for each esc. I also have the "lack of budget" factor to add in to the equation but yet.. still gotta be fast enough to take out a couple traxxas boats and still keep that lead! Help me out if you can!
Did you ever put this into a APP ? If so, where can I find it. Always enjoy your Videos.
It's not in an app. But it is inside the Google sheet on the patreon website
Good night, thank you for making such an informative segment. I'm currently putting together a twin brushless catamaran. I have 180A ESCs and 4092 SSSMotor 4pole motors, the Hull is 38" in Kevlar. I watched your segment on timing, I would like to say that I'm new to boating. Do you think I should reduce the timing from factory set 15.00°. Available reduced values are 11.25°, 7.50°, 3.75° and 0°.
Once again thank you for patients, be safe and family.
Hello, thanks for the comment.
I prefer to run a brushless motor on sensorless mode with variable timing controlled by the ESC. The settings are then ranging from low to high where I like to select low timing for this type of setup and try from there.
If your only option is fixed timing at a specific amount of degrees I also would start low here and find out where your sweet spot would be from there.
@@RCexplained I believe that the intervals are fixed. Is going to 0° down from 15.00° going to negatively affect my 4092 4pole motors? I'm using Seaking 180A ESCs. I haven't scrutinized the manual in detail.
Great video. I love to see a mathematic equation being used to be informed for picking components. Just one problem. The equation says it’s good for boats up to 50”
What if my set up is 72” what changes with the numbers to come up with a good set up for that? Why does it change at 50”?
I don't have any data outside of 50inches to conclude that the formulas for a surface piercing fast electric boat works at larger sizes.
I have a wooden model boat that I want to turn into an RC boat! It weighs 600g and is 60cm long and 18cm wide and already has a propeller with a diameter of 43mm. It has a v hull. I want the bot to be able to level but it doesn't have to go super fast. I want the bot to have a range of 30m and have a battery time of at least 15 minutes!
Can anyone recommend some parts? I'm completely new to the hobby😅
Use a small outrunner with a lower Kv and run it on a 3s LiPo with at least 5000mAh. More capacity more run time.
40inch Catamaran built with 3mm plywood
With dual 4092,1550kv,200a
6s 7000mah 60c per motor 12s of total
What do you think about this setup and this is ok then suggest me good propeller
Super viedeos. Wher can i folow up the fomulas? I do not understand compleetly. thanks
Great info for sure. To test the 🧠
I have a 51in v hull (gas to electric conversion) so one shaft and prop.
For a one motor setup this will be crazy big motor/esc is expensive and the battery requirements 🤯 so I like to use two motors turning the same shaft. Should I just Divide my motor wattage results and run two smaller esc's an motors? Seams like I would have more options and tuning...thank's!
Yes that will work. Match the RPM and Kv with the gear ratio used.
Great video, Thanks! I need help for power system configuration of a catamaran with two engines. What are the values to change?
Select a higher unloaded rpm within the range for your twin setup. Or use slightly larger props on the twin setup.
Wow that's a lot of information my brain hurts great video though. I think I'm going to find somebody with the same boat see what they're reliable bashing set up is and of course their temps and try that if not I'll go back to college and check out your video again
Is the power system eqution the same for other hull types?
Yes, however a more efficient hull can benefit from a bump in rpm
what is the best for a racing boat?
1.water jet
2.prop shaft
For speed. Propeller. Jets are inefficient.
Good video! Easy to follow. I've tought that mine setup was around the same as yours but someone mentioned his props are always below the water surface and that messed up my mind and my calculations. So what to do when it's 31" v hull with two motors and a gear ratio of 3:1, the stock props are 45 mm. It's an old Graupner Portofino I'm building but I wanted to replace the old brushed motors (with in this setup had a top speed of 20 km/u) for more speed. Hope you can help me
This is a great video with very good information on how to get the correct power system for running electric with RC Boats! I've been on the nitro side of racing for years but I want to get into electric, I see the advantages! Can you explain more about how you "data log"?
Glad it was helpful! Some ESC's have data logging built in. In other cases you can buy a stand alone data log to gather information. If you are not using data logging, knowing the temperatures of all components is the next best option.
I am about to replace evetything in a big RC Yacht with a double Brushless setup that I intend to do with 2 ESCs. Also it is my fist contact with brushless on my own. You cannot imagine how much this video helps me to start.
For the intended double motor setup, I have halved the overall Wattage that came from the hull length. If you have further advice for me about such a setup and its layout, I would welcome it.
Thanks for your comment, just keep in mind the formulas are for a surface driven prop. If you are running a fully submerged prop you will want to decrease the overall rpm by a significant amount.
@@RCexplained Thank you! Also it turned out that i am very restricted in the (fully dived) prop diameter, like 3,5 cm instead if the theoretical 4,4cm. Can you please tell how I should adjust my choice according to that? Should that make me reduce the RPM even more and that is all? Thanks four you answer in advance!
Did my "Super Thanks" donation and comment from July 18 get deleted or was there a misunderstanding? I'm completely new to RC anything and this is the most helpful source I've found.
Hey Ron, thank you for asking about this and Appreciate your "Super Thanks" !!! I don't see where it shows who and where it came from but it does show up under the super thanks category in monetary form. Perhaps the comment that you made did not go through some how? It doesn't look like I can see who it was from if there is no comment, however, I am quite new to this and yours is the first one! Thanks again!
@@RCexplained No problem, I was just saying that this and the radiocontrolinfo calcs are very valuable information and I followed along every step to make sure I was doing the correct thing for my boat. My boat is very similar to your example at 36".
My question is in regard to the ESC selection. My boat uses 2x2s batteries or 3s, but many other owners of my boat have claimed they had to upgrade their stock 120amp ESC to a 150a or 180a ESC to run 6s, even after cooling mods, because they "fry" them.
As I calculated your current selection at 9:33, it shows the current as smaller as the battery cells go up. So 6s would be 60a x 1.3 x 1.3 = 101.4 where 4s is higher at 88a x 1.3 x 1.3 = 148.7 current. Am I getting something wrong where going from 4s to 6s looks like it would require a smaller ESC? I'd like to do the right thing before throwing 6s in there. Thank you very much!
@@ronchang9791 6s in the boat is going to increase the current if you are not changing anything else in your power system. If you changed the prop out to a much smaller prop, you can reduce the current.
In the example we can reduce current by moving to a lower Kv motor when selecting the motor Kv. You can also reduce current by swapping out your motor to a lower Kv.
You can try doing a mock up system with both 4s and 6s and see the differences in the power system selection process. These differences allow wattage to be the same.
Thanks
No problem
Can you help me configure my 2 bldm with controller. I made boat with 2x 1400kv bldm. Now I need to rotate one clock wise and other counterclockwise. But my problem is when I turn right I need to off one motor and when left need to turn off other. How can I do it with one stick. My transmitter model is FS-CT6B. Can you help me figure it out.
( pressing forward both motor rotate. Forward + right only one motor rotate. Forward + left only other motor rotate.)
Thanks
Hello, it does not appear that your radio has mixing capability. A programmable radio will allow you to do this with ease.
@@RCexplained thanks a lot... I hope you will upload this type of video and help people to make good knowledge....
Hello, first of all, thank you kindly for video - it really helps! I`d like to ask some questions regarding it. I`ve calculated amount of power I need for my boat (22 inches - approximately 400W) and I`m going to use two engines separately. Shoud I divide total power amount by two then and proceed with 200W? Thank you a lot, truly.
I bought a tfl zonda boat 2x motors 3674 2075 kv with 120amps esc so I bought 2x 6s lipos 5000mah 22.2v that should be able to have it,stock props and timing set on p? What you reckon?thank u
I have a 150lb boat mono hull, that I am trying to push along very slowly, maybe 2-3mph for a long period of time, meaning an hour or so.
I am so confused on what the right combo would be. Will a small prop or big prop be best, will a 5400mah battery last for a while. Uggggg.
A large diameter prop with a very small pitch turned at a very slow RPM. 5400mAh can be enough if you base your system on drawing 5A at full throttle.
Super awesome. I am going to have to do some math. I’m 3D printing a Riva mono hull but it is supposed to be a dual prop.
How does the math change if your using 2 props? I would like it to go fast but I’m a newbie and not looking to race etc. I would like to keep costs down just a fun project.
I’m planning on using 2s Lipo batts. I can use single batt or 2 batts.
I'm also trying to build a motor setup on my 2-propt mono did u figure the math out? I'm really struggling to find the right motors and battery
How would these change if you wanted to run a dual motor setup. Assuming you could chop the wattage in 1/2?
Great video, can i use these calculations if i want to use 2 motors?
Yes but you should alter the formulas to account for dual motors. For example, power output r equired per motor is 80% of the original calculation.
Would you be interested in diving deep into NAVIGA M section Eco class boats and how to pick out power system that is within the rules?
I would have to look in to that class. I have never raced in it and thus do not have any data.
Great video as usual. I've got a couple of questions, as usual.
I may have missed it somewhere, but how di you arrive at the 24-33000rpm with most motors have a 50-60000 range? Reliability, a power range I missed, or both.
And for the cell count on the esc, most have a range. 2s-6s for example, or a 4s-8s that I'm looking at, would I be best off with matching themax, or in the middle. I am planning on 6s for my speed run car. I know the math will be different, but I'm trying to understand the overall picture here.
Thanks!
Thank you Adam. The RPM range is the range that is best suitable for RC boats utilizing surface drive props.
An ESC rated at 2-6s can work for 2-6 cell LiPo.
Thanks, I'm on the technical side, and when I hear "X", it's "X". I'm trying to figure out my speedrun build, and I'd like to get the numbers right, from the beginning. Everything else is to be setup based on my power system.
I've been getting high wattage, voltage matched gear, and the kv for rpm just under the max rpm of the motor. Allways a little headroom, an I can't over rev. Am I in the ballpark in my thinking? With resistance and size, so forth from your other highly informative and engrossing videos, of course. Bad with math, good with spec numbers, with an electrical backround. I get what your saying, your great, but I lose some of the math. Sp I tru to get the concepts down, and take my time doing the math, once I've narrowed down the field.
Thanks for the grest info!
HI Adam, you are on the right track.
The best info thank you
Glad it was helpful!
Hi i am meber now of rcexplained. Where can i find the excel sheet? Thanks
Good morning and Merry Christmas to you and your family. I really enjoy your information videos, they have guided me over the last few years through nitro buggies, crawlers and boats and I want to simply say thank you.
I really need your help. I got myself in a pickle. I purchased a catamaran Hull (38.5") and twin 4092 SSS 4pole 2140Kv motors, 180Amp ESCs Hobbywing V3 and 48mm 1.8 pitch 3 blade CNC props. I am not able to calculate my safety or ability of this setup. I have other props ( 17/16 2blade, 45/1.9 2blade and 40/1.9 2blade) that I can try out. I just wanted to go about 100mph +, but I may have bitten off more than I can chew.
I only made that setup because TFL has it in a couple of their boats. Anything you can help me with is highly respected. God bless and Merry Christmas.
Forgot to mention, I'm using 6S 6000mah 100c Graphene batteries.
Kv is a bit higher then what I would prefer, even for straight away passes. Only 2 WOT passes and then bring the boat back in. You will want to start as small as possible on the prop and work your way up. The pitch on your props also seem very high. Do you have everything installed?
Merry Christmas to you as well!
Also, does Kv have a different effect in relation to 4pole vs 6pole? Can you please, respecting your patience, help me to start understanding some of the science?
Hi Ryan,
I'm conducting a thesis project on USV's and the vessel is of a similar size to an RC boat. I was wondering if you would be able to share how you derived your equations for power required based on hull length and prop size based on motor power?
Thanks.
These formulas were developed empirically.
Hello Ben! hope you are doing good. I want to know what type of thesis project you have done on the USV and can we communicate on any other websites as I am also doing a thesis project on the same topic. I have some queries related to validation point of view, I would greatly appreciate your assistance towards me, and it would hold significant value. Thank you!
Hello! I want to know the constant that you have used in the first equation where you are calculating the power of the boat from where did you get that specific constants of 4.279 and etc? Is there any proof of concept behind it please explain or an website or research paper.
from a data set
@@RCexplained can you elaborate a bit more, from where did you get the data set and which data analysis and statistics technique you have applied to get these values. I will appreciate your help.
I collected the data, plotted it and used trend lines.
@@RCexplained okay. Thank you!
How do you modify the propeller calculation for a submerged prop, as I presume taht the load is approximately doubled for both blades being in the water at the same time? Thank you for your insights, it should save me a load of money in failed experiments!!
You will have to modify the RPM range as well as the power range first. Overall a submerged prop will require less RPM. 10k-25k depending on the size of the hull. Power will depend on your speed goal. Size of prop will be reduced and will largely be based on your chosen RPM, motor and power potential.
Ok this video definitely helped answer a lot of my questions but I just picked up a boat for my kid and it’s already built but has no battery’s how to I figure out what batteries for it
Catamaran hull 32”
Ammo 36-50 3300kv
Phoenix ice light 100
Prop is a 40mm
I'm not a fan of that motor selection that was included in your purchase. Typically a 32in boat would take 4s. But with such a high kv on a small motor, I would run 2s.
This is a great video, very informative. Is there a reason why hull weight is not a factor in these calculations? I am working on a conversion for a vintage hydroplane that is wooden, so significantly heavier than the modern hulls.
Yes, it is assumed that hull weight is within the typical values for a specific hull type using a surface driven prop.
Is your calculation for finding the wattage on a cat different from a deep v hull? If so can you point me to the correct numbers?
No it is not for simplicity.
any suggestions if i want to use two motors (so i can have differential throttling for steering) for the 6ft long aircraft carrier I'm building? the I want ESC's with reverse as that might affect my motor power options to suit the esc amperage.
Just a heads up. The video is for surface driven props on fast electric boats. For fully submerged prop significantly reduce the amount of power and motor rpm as your targeted speed will be very low.
I'm terrible at maths and struggling the with squared Clculation.
I have a 29" catamaran I want to go as fast as possible 😂
Great video. It is a starting point for me. I am currently building a 60" PT boat (1/16 scale). Question:
The formula domain is for max hull length of 50". What do I need to change for my current build?
Also still debating on 1, 2 or 3 motors depending $$$$
The formulas are for a fast electric boats with surface piercing props. Does this match what you are doing?
@@RCexplained No it does not. My props will be below surface
With a submerged prop you will want half the RPM dependent on props diameter require for that hull size.
Great videos! Curious what your take is on underwater thruster designs. I am designing my own version of a T-200 thruster (pretty much underwater EDF) and am wondering if the same rules apply. Mind you this is gonna be a kayak assist motor so will never reach much speed so I wonder about the drag. Will have to play with prop pitch for sure.
The formulas in the video are for a surface piercing propeller
@RCexplained understand that, that's why I ask your take on what the differences would be in calculating for a somewhat ducted outrunner thruster version
Lower RPM than the range provided in the video and less power would be the main difference.
Great informative tutorial video!
I do need your reply regarding my boat setup.
Im using 3S 7600mah 70C x 2 Series connector at 4092 1700KV with 180A Seaking and tried with 40-42mm props but only manage to get 80km/hr on the Cataran 1040 total length.
Did i go wrong anywhere on the setup?
Can the boat reach 120-130km/hr with the correct props? Please advise... Thanks mate!
Hi Dayak, what is the temperature you are getting on the battery, ESC and motor? If you have room in temperature to go up, you can try slowly increase the size of the propeller. Getting to 120-130km/h may be tough as that is a big ask.
@@RCexplainedtemperature of motor +- 50°C, Esc +- 60°, batt 45-50°
Your batteries are getting up there in temperature. Overall you can squeak a bit more power out of the system by going to a slightly larger prop. Keep an eye on temperatures and once you exceed a safe maximum you've reached your limit.
@@RCexplained can pls advise the maximum temperature for the batteries, esc and motors?
What happens if my boat is 168in and is not fit for the formula, what should I do? Should I use a different formula?
What type of surface drive fast electric boat do you have?
I am working on my first rc boat 36" long. The data you gave is apt. But i have already a 2650kv brushless motor and a 200a esc. Will a 4s 5000mah battery works well on this. Appreciate your suggestion. I find your videos educational. Thanks
Hi Boni, a 2650kv motor on 4s in a 36inch boat is going to be a tough combination to work well. It's not a setup I would recommend or suggest. The motor is going to require a smaller prop then what your boat may need.
@@RCexplained thanks. Ive changed my mind and go on two 3450kv with 50a esc brushless will be connected parallel to 6s 5400mah battery. My prop are 3 leaves 36mm 1.4pitch. I hope this will be a good set up. More power
Hi Boni, you are moving in the direction of more smoke coming out of your components. 3450kv on 22.2v is 76590RPM unloaded and would be far too much. What did the formula in the video say to use for kv, power and prop size?
I would expect twin 36x74mm motors around ~1400kv using running 6s to be much better for you. You would need 80A ESC's.
Hi, I have a 40 inch mono hull.
What setup should I be using? I tried to figure it out, but I ended up with huge C ratings, low kv and when I look at batteries and engines for sale I can't find anything that comes close to fitting....please help.
What speed are you looking for?
@@RCexplained well, I got a ~50cm prop...Im not looking for the max speed...just something fun, its my first rc boat. I was using the lowest rpm you had 22500 iirc. Any help? Thx for replying:)
Use a 40x92mm motor around 1000kv. 120A ESC rated for 6s LiPo. Use a 6s LiPo minimum 5000mAh 45C. Use a 48mm to start and work your way up from there checking heat frequently.
i building same thing from scrach this is the things i got on hand wanted to know in it woould work
I learned a lot from your video. Question- how do I include the weight of the boat into your calculations. I have a 26 inch, wood, former nitro, tunnel hull. It is 5 pounds. This is much heavier than a comparable fiberglass boat. Right now, I seem underpowered. Appreciate the help.
What setup do you have and what setup does the calculations suggest?
@@RCexplained With my own guess- I currently have a 3650kv (600w nom) with a 90a ESC which called for a 2s battery and about a 42mm prop. The ESC kept stopping and overheating. After calculating using your system, and with a 26in wooden tunnel hull, I calculate a 1690kv with a 36mm prop and 4s. What do you think?
I am using the minimum power output of the motor specs- 600w
I am most unsure how you determine the output - help
Ok, yes around 1800kv, 4s 5000 lipo, 40mm prop would be a reliable 35 to 40mph.
how do you calculate required thrust for submarine underwater and above water .can you please tell me. thank you
The required thrust would depend on the speed you plan to achieve and then your submarines hull shape and size drag. You would need enough thrust to match the drag created at speed.
This is a great video, but I am lost! lol. I have my sons 34" mono hull that I 3D printed. At first I just went with the specs the designer used which was a 3650 motor with 4200kv, 3S battery, 36mm prop and 150a ESC. We burned the motor out in 10 minutes. Not sure if this is just because it was a cheap piece of junk from Aliexpress or if it was just improperly sized. I think, based on the calculations I could follow, I am better of going with a 2450kv motor. Any chance you can confirm or deny that and maybe steer me in the right direction? Any help is greatly appreciated!
I'd go with a leopard 4074 to 4082 leopard motor with 4s LiPo and a Kv of around 1800 to 2000. If the ESC can do 4s you are good. Start with a 40mm prop and work your way up.
@@RCexplained Thank you sir!!! I appreciate the help!
@@RCexplained I have been digging into the motor dimensions and the hull. WIthout changing out the motor mount (current one is also 3D printed from the hull designer), I dont know if a 40mm will fit. Am I still safe going with a 3650 on 3s? Would I want a similar KV or slightly larger kV? Or do I go with your recommendation and purchase a motor mount or design one of my own?
@@sirbeck58 can you do a 36x74? What is your target speed?
@@RCexplained Speed isnt a large concern of mine. It is a 3D printed boat for my 5 year old son. 30mph maybe should be plenty for him. My main concern would be keeping the diameter at 36mm so that I can still get a cooling jacket on and fit in the hull. It uses a straight solid shaft design, so the motor is low in the boat. If I had to go with a 74mm I could, I would just have to relocate the ESC. Not a huge deal there.
Hi there,
Its awesome to see your knowledge in this area. Being new to this I had a bit of a hard time following everything you where speaking on. My son and I are building a 48” mono hall and I’m looking to get 25-30 mph out of it. I got the first calculation of 3900 watt/power but was lost on the rest. Any chance you could help me out so I can order what’s needed to complete the electrical set up.
Thanks
Have you decided on batteries that you will run?
@@RCexplained
Thanks for getting back to me. I’m going to be running 5200mah 11.2 volt 3s. I know I could go way bigger but it not really about speed for me. I’m going with a 60amp esc and 3650 motor. The boat is going to be more for fishing (as I’m mounting a fishing reel and rod on it with a worm gearbox and secondary esc to run the reel)
Any thoughts?
Thanks
Is your prop submerged or is it a surface drive?
@@RCexplained
Surface driven.
You could go 3s but you would need to be up around 100A minimum or so to have a chance at 30mph with a low drag hull. The motor will have to be at or less than 1600kv. 50mm prop.
You would be better off with 6s minimum and an 800kv motor using a 50mm prop. 100A ESC.
Minimum Motor size recommendation for either cell count is 40x82.
Typical fast electric boats at this size are using 10-12s LiPo at 100A for 40mph and up. Your application is a bit unique. Keep RPM's on the very low side of the range.
This video is awesome. I'm working on an RC plane currently, but would most of this info work for that context too? My initial issue is finding the correct wattage required which is your first step here. What flight parameters drive that? Thanks!
Hello it would be quite different. What kind of plane, what wingspan and how heavy?
RCexplained Unique design that has similar dimensions to a scaled down 747 and is also a pusher configuration. Wingspan of 6ft and target weight of around 17 lbs (including motor, batt, etc.). Let me know if you need any more info.
You will want to be around or over 2000 watts for that size. 100-150w per pound
RCexplained thanks! Really
Helpful videos, keep it up!!
Do the differences in hull type ( Deep V, Cat etc. ) change the formula for the power calculation?
No I don't think the formula did, (can't fully remember) the result will be a different speed achieved for the varying hull types.
Thanks for sharing the video! Very educational!
For a 50" mono-hull deep V boat for autonomous mission not tailored to be very fast which formulas should I get?
Thank you
Hello formulas in the video are for a surface driven prop. For a submerged drive, everything will be very different. What speed are you after?
@@RCexplained Thanks for the quick reply. The boat is this one: ibb.co/bPt3SL9
Looking for no more than 20mph. It will be cruising around most of the time at slower speed
Link Doesn't seem to be working. If the boat will be travelling at slower speeds mostly, I would have the components selected specific to this vs hitting higher speeds closer to 20mph.
You have options, you can run 6s LiPo on a large outrunner with a 60mm prop or so.
@@RCexplained Please try this link instead: drive.google.com/file/d/1ycz61qqw2JDgFh55scEQJhSE7pGiYVvE/view?usp=sharing
Do you think that a 4084 620kv, 6s Lipo, with a 60mm prop (1.4 pitch ratio?) would be a good starting point?
@@RCexplained Please try this link instead: drive.google.com/file/d/1ycz61qqw2JDgFh55scEQJhSE7pGiYVvE/view?usp=sharing
Do you think that a 4084 620kv, 6s Lipo, with a 60mm prop (1.4 pitch ratio?) would be a good starting point?
But what about the RC part? Do boats have controllers like quads to combine the inputs from radio into signals of the motors? There are 2 motor configuration, but all I've seen - the direct commands from radio to ESC
Rx to ESC. No other controller is typically used
:(
@@RCexplained but in this case - no telemetry, no stats, no fpv with all this online info :(
You don't need a "flight" controller to have telemetry or FPV.
@@RCexplained I want to have telemetry "on FPV" (displayed current draw, component temperature etc), you've said in this video - send the boat to water, return home, measure temperature :) guys on quads & planes do not need to return the model to get all this info
Another quick question ,, can I use 80A brush less ESC and 4000kv brush less motor with 2to3s lipo and 33mm prop for my 23 inch RC catamaran boat that I have built ?
2s 4000kv and a 32-33mm prop can work. 3s not recommended
So I should go a head with 3400kv brush less motor with 80A brush less ESC with 2to3s lipo with 35to36 mm prop to reach the speeds of 70to80km/h .??
Getting a small boat up to 80km/h will be tough. If you want to use 3s LiPo you will have to use the lower kv. Preferably around 3000-32000 or so. You can use 3400 but you will have to monitor heat so nothing blows up.
@@RCexplained can I use 3000kv brush less motor instead of 3200kv brush less motor ? And what should be the ESC for 3000kv motor ?
Hey! Somehow I get the calculation on step three wrong ... it will be - 600 approximately. I have a 20 inch long boat and 8 inches wide if it matters and count exactly as you describe in the video. Do you know what I'm doing wrong? Just thinking that -600 watts can not be true. Sorry if my english isnt right, i used Google translate beacuse i an lazy but i hope you understand!
Yes -600 doesn't work. You should get something closer to 350w at a 20inch hull length.
Really struggling with the math. When I run your equation the result is -2500.376. Not sure how you got to 1302.624. Trying to power my 29" Catamaran.
Hi Joel you can put it in excel or run it in an online math calculator. I also have a calculator within the download able spreadsheet on the patreon member site. You can can also drop the number here and I can try and help out.
Hull lenght dont see how accounts for weight or is there assumed weight per inch
Weight doesn't make much of a difference unless its in excess. Hull length is the strongest factor.
Good morning
1) mono 2 competition
2) 80cm
3) 6S 22.2V
4) 6000mah
5) ESC 150 minimum
6) mandatory limiter, and
transponder
7) 7 minutes of autonomy required for the race
8) minimum voltage after race 3.3v per element, otherwise
disqualified.
can you help me
to design this mono 2
Try working backwards from the limitations.
Using these equations approximately what speed will a mono-haul go? I want scale speed for my model so I don't need to go over 13-14 MPH.
These equations are for a surface driven propeller. Does this match for you? On the radiocontrolinfo website, there are calculators to help determine and estimate. speed based on your calculation.
I'm sorry I could really do with your help on this!!!!!!!!
What is your question?
whats the formula for larger ships, mine is 80 inches long
I Peter, I don't have a formula for submerged drives yet. Something to look in to for the future.
@@RCexplained it is a 2.2m long scale warship with twin motors
Hey I'm building a 23 inches catamaran RC boat ,, so can you please select the battery , watts of power and motor kV and size of the motor and ESC for me please ,, ,I'm a bit confused
What was your speed goal for the 23inch catamaran?
60 km/h - 37 miles/h.
I'm new for RC boats and building them so I really need your help in selecting the electronics for my 23 inch catamaran boat ,, I don't want to fail in it ,, 🙏
Hello. You could try 2s 5000mAh lipo using a 36x50to60mm 3200 kv motor using a 100A esc and a 37mm prop.
@@RCexplained thank you very much .😊😚
Great video. My English is not very good
It’s possible that you recommend me what motor to get..??
I’m building a catamaran rc boat it’s 70\34 cm
Thank you very much
What is the length of your boat?
Hi thank you
The length is 27' inches
I'm completely confused about what battery esc and motor to buy
I'm not looking for a very fast boat
Thank you for your help
Hello, you could use a 4s 45C LiPo, 60A ESC and 40x65mm 1800kv motor with a 40mm 2 bladed prop. This would be good for about 60km/h.
@@RCexplained thank you very much
What power should I use for a small I inch baot
One inch? No idea, unfortunately.
@@RCexplained 8 inches
A brushed 130 size motor is what I would begin looking at.
How would you use this for a twin mono setup!
I would just add a multiplier to the power calculation. Each motor is 80% (if looking for higher speed) or 70% (looking for a lower top speed) of the power that you calculate using the in video formula.
hi, greetings from México, I just made a fiberglass boat, is 32 " or 820 mm, the weight is 2.174 kg, my problem is that I have no idea about the engine and electronics, I made it for my grandson, can you help me to select all the items for my project?, I relly want to finish it any time soon; by the way, if you need it I'm a fiber glass specialist modeler.
Hi Jose, awesome project. Send me an email, my address is on the about page. I can help.
I have a 60a esc water cooled in a deep v 36" boat would a 3000kv 4 pole work?
Does this motor hit the required power level you are looking for? Does the motor give you a good unloaded RPM based on the voltage you plan to run?
@@RCexplained unfortunately all I see is the esc amperage
A motor usually don't have a specification for the required ESC amerage. For unloaded RPM, you would have to calculate this based on the setup you are running.
@@RCexplained could you reply to me with the formula so I can
kv x Voltage = ~25,000RPM. These formulas are in the video.
Just to clear out things, You mean 26000 instead 28000 was used in computing Kv, right?
I am not sure why I wrote 28,000, this should have been 26,000 as the answer is correct using 26,000.
i have 2 3s 11.1V 50C 5200mAh how should i use them
series or other
and what kv moter and elc and prop
Specification:
KV:2650KV
Max Voltage:21V
Max Amps:80A
Max Power:1600W
Rotor Poles:4
Number of Turns:3D
No Load Current:3.2A
Max RPM:60000
What boat? Start with the length of the hull. These values can be entered in to the formulas within the video.
@@RCexplained 34 inc same kind in vidi no good at that kind of math
Can you please elaborate about the power equation?
Elaborate about what specifically?
@@RCexplained Thanks for the reply. How did you derive it?
Sorry, I missed your reply, I derived the equation through experience and statistical data.
Forgot to mention, I'm using 6S 6000mah 100c Graphene batteries.
yes, even 6000mAh 100C will be stressed with that setup.
Yes. I took it out with the stock 4519 props (2blade). I bashed for about 20 minutes between 50-60mph, the motors and ESCs were lukewarm. It took me about 2min to open the Hull to check. But so far no heat from the batteries. I have never done a high speed run yet. I'm in Canada so that means crawler season.
I found the sheet but the calculation is not cmoplet
What's not complete?
Thanks for sharing this info. What are your thoughts on the motor and ESC for a deep V hull 40" long with a jet drive? I have not picked a jet drive size yet either. Thanks