You are so much help in understanding how to setups rc boats I'm currently doing a bass wood fiberglass resin reinforced scratch build mono hull 51" cabin cruiser and I'm planning on running 2 4082 1250kv motors with a 42mm 1.4 prop....the goal is 50-55mph out of this boat so I can keep up with my big boats and put a camera on the rc boat to get rolling shots of my big boats out on the lake. Keep up the work

@RCexplained

Жыл бұрын

Sounds like a great project.

Holy balls i just started looking for info about rc boats today. Watched 2 or 3 other boat videos of yours and bam this one came up. Good timing

Pitch on the prop to take into consideration

Subscribed! Will check you other videos.. Currently designing a ww2 torpedo boat 1/48 scale 15", not into speed but more on a realistic movement. If lucky in the future i can make the 1/48 battleship between 17' to 18' long and that would be a headache for me choosing 4 rc motor lol

Hi! I have a 60” inch deep vee from Arrow Shark with their twin M8 style scale drives. I decided to power it myself, because I’m hoping to get the largest fastest setup possible. Arrow Shark says I need 56104 or 56114 500-600Kv motors with 300A ESCs and x4 6S 6000mAh 100C. What do you think of this setup and how different variations within this range affect the performance? Thank you!!

Nice video and i have an idea fro a future episode.. Would you be able to touch on why some ESCs like the XLX2 have problems with HIGH KV Motors? The instructions say it should not be run with a motor over 2000kv. Thanks again for explaining how the RC components work.

@Liberty.Francis

2 жыл бұрын

The xlx2 works fine with higher kv motors. The only issue is with 56mm and 58mm 6 pole motors and higher than 1300 kv. With that said any 4 pole motor it will run just fine.

Good to hear from you again, are you familiar of Whiplash 20 hydro? I’m building for racing an electric version, any suggestions? Thanks.

I’m starting a 1/24 scale 49” fast MTB with 3 prop shafts and a GRP hard chine mono hull. The formulae in the other video mentioned give results close to what retailers recommend for this model, but the formulae are for a cat with a single surface piercing prop. I wonder how the formulae change for a mono hull with multiple submerged props. I got a hull power of 4.2kW, did the calcs for 22,500 rpm and got three 2kW water cooled in-runners wound for 1500KV and weighing 500g, each on a 4S 8Ah battery with 120A ESC and a 42mm P1.4 prop. Anyone here got better ideas for this boat, or suggest how to shift these results to best suit a hard chine planing hull with submerged props? Changing motors and prop shaft geometry on this after glassing in would be a royal pain!

Hello! I have a 2150 kv boat motor and planning to use it for a 80cm v-hull. The total rpm will be 31820rpm. Is this too high?

@peteroosterhoff8850

Жыл бұрын

Works fine depending on voltage your gonna use. My mono's (85cm/33inch) are driven at 6s with 2000kv motor en propsize about 42-45mm. Suggested is experience with boating. But that could be a indication for you. Or look for example for simular boats on KZread and what they run... prop is also very important. Got different v-hulls, one runs best on normal 1.4 pitch and other boat likes 1.6 hi rake...

After change the esc and motor on my sr80, my boat suddenly runs very slow. What is the problem?

@hmz6535

9 ай бұрын

What size of motor did you installed and hull length?

thanks for your useful videos , blackjack cat comes out from the factory with a 1350kv motor running @8s that would exceed the rpms (4.2x8 =33.6x1350=45.360 rpms and yet not pulling out not more than 160 amp , can you please give me explanation how such a setup could be achieved , thank you

@RCexplained

Жыл бұрын

Using the nominal voltage the rpm is a bit lower than what you have. The problem with using a setup with a much higher nominal rpm is that the range of propeller options diminishes. Using a larger prop that is outside the range is the ultimate conclusion to a setup that could burn out the power system. The manufacture and designer understands the limitations and provides a prop that would work well with 6s and 8s. 2 different propellers and it is these choices that allow the high RPM setup to work. The range of rpm is for new boaters to make the kv choice align with an easier boat to setup. I typically get questions asking me if a 2200Kv motor would work for 8s. And this spells disaster as you could imagine for an rc boat.

@mauriziobezzina3378

Жыл бұрын

​@@RCexplained thankyou for your precise explanation ,so technically speaking it s all about the load being applied to the motor, the more load it have the more heat generated and eventually burn the setup .at the moment i have a tp 5660 1170kv rated at 48voltz max ,208 amp max ,53k rpms specs are stating also that continuous power is 5500watts and maximum power is 10000watts , i wish to make a setup to get the most power out of this motor reliably , i see alot of people burning alot of escs and i wish to get the best setup not the hard way , if it s stated at 48 volts 53k rpms , can i give it 12s ? but that saying goes against your rules of exceeding the 35k rpms on 12s it will get up to 53k rpms which is also stated by the manufacturer ,i m a little confused ,

@RCexplained

Жыл бұрын

@Maurizio Bezzina if this is your first boat build, I'd recommend running the motor on no more than 8s LiPo. What boat is this going in? For rc boat applications, it's quite difficult to utilize the full potential of a brushless motor. Using an efficient direct drive system doesn't allow flexibility in gearing changes to get an appropriate output rpm. Also check out my video on selecting a power system for a boat. Some good info there that may help you.

@mauriziobezzina3378

Жыл бұрын

@@RCexplained for the last 10 years i did only run setups up to 6s and 180amp esc which i had plenty of fun and success , i was always afraid on going much higher setups since motor ,lipos , and especially esc are more expensive , this coming year i want to take the step and go for it ,i find your explanations very useful and well explained thanks again for that , i was confused because motor rating is at 53k rpms but at the same time they are way over the recommended 33k , so as far as i learned now is that i cannot get the full potential of a motor although its ratings , that s why is stated that continuous power is 5500watts which i now believe it s the reliable voltage to go (8s) Boat will be a 50"mono deep vee with flexible surface drive ,so my setup will be 2 x 4s 6000mah 100C lipo 300amp ztw esc and the 5660 tp 1170kv everything connected up with 8mm bullet connectors , I will start with a 2 blade 48mm x 1.4 prop and check the temps accordingly each run and eventually go larger prop , when temps start to go over 60deg c i stop increasing prop size and go a step smaller .

I'm thinking about buying an old Nikko Barracuda and upgrading it to brushless. Would it be faster on 3S running lets say a 2400kv motor or on 2S running lets say a 3400kv motor? Using that RPM conversion they would be putting out roughly the same RPMs. But wouldn't the 3S still be faster? Also, what size ESC would you recommend? Thanks in advance

@RCexplained

2 жыл бұрын

I had this boat at least 20-25 years ago. It will struggle with a significant amount of power, not the greatest hull for more speed. In terms of 2s vs 3s, typically, the larger motor will produce the highest top speed. 3s would be easy to do this with. A 30A ESC 3s battery will easily make the barracuda uncontrollably fast.

@NWguy83

2 жыл бұрын

@@RCexplained yeah I wasn't expecting a speed demon. I just thought it would be neat to upgrade a toy grade boat from around the time I was a kid and really wanted one lol. So probably just a 2S lipo and a 20A ESC then? I was looking at a few motors and was wondering which one(s) you might suggest since you had a Barracuda. A. 2218 2750kv B. 2948 3450kv C. 2958 3380kv D. 2968 3400kv E. 2968 3800kv

@RCexplained

2 жыл бұрын

Smallest motor with the lowest kv on 2s. 15k RPM will br a lot.

low rpm needs higher pitch high rpm needs lower pitch high pitch ratio raises the stern low pitch ratio keeps stern lower so a mono hull needs low lift. witch mean low pitch ratios. 1.2, 1.4, maybe 1.5. In order to get top speed with low pitch AND low RPM you have to use a MASSIVE diameter. Something has to give. and It simply cannot be pitch ratio. thus you have to run higher RPM's. 35k under load. 38k unloaded. minimum on a mono to break 60mph with 68mm+ total pitch.

I have a 26cc gas powered 50" long x 14" wide and 14 pound weight (with engine), 11 pounds (without it) Enforcer type deep vee fiberglass hull that I'd like to convert to brushless. My goal is to run sport not expert racing; but a little more faster than the gas engine can; any suggestions will be appreciated' I really love this hull and I intend to keep it no matter what; therefore; money is not the problem'

@RCexplained

9 ай бұрын

A good place to start is the video I did on selecting power system components.

nah, we race at 45k-50k rpm

Left out a very important detail. Prop size. These tests should only be done with the boats stock prop size. Great video tho for the newbies

@RCexplained

10 ай бұрын

Great point!

so a lot of my have 2000 to 2900kv fast boats and i use 3 to 5 s ...so 5 x 2000 means only 10000 rpms... I love all the way my boats perform with the props i chose...i am confused by your 20000-30000 rpm numbers.. i think thats way higher then needed...

@RCexplained

Жыл бұрын

Check your calculation. 3s and 2000Kv is 22,000RPM 5s and 2000kv is 37,000 RPM

@roadstar499

Жыл бұрын

@@RCexplained wow... so all my boat are setup nicely... do you have a video on this math/calculation you use??? i don't get it at all.. thanks

How do I keep my motor still it shakes to much I think it’s rather my hull to small or the motor to fast

@RCexplained

Жыл бұрын

Sounds like it's out of balance.

@deinsports8328

Жыл бұрын

@@RCexplained do I just glue the motor on the boat

@RCexplained

Жыл бұрын

@@deinsports8328 you fasten the motor to the motor mount

@deinsports8328

Жыл бұрын

@@RCexplained oh I don’t have a motor mount

We run between 45-55.000rpm unloaded rpm for most of our projects. We also do this in curcuit Racing and batteries last for about 1 minute on wide open throttle. :) Thanks for great content, please check my Channel out, maybe there are things of your interest too. 🙌🏻

Why is it that most all 3650 motors say there rpm is 50,000 but using your formula they are usually 33,000. Is the manufacturer just overstating there product. Which number would you advise using. I used the 50,000 number as I had not seen your video yet. I put a 3650/3100kv motor with a 120a esc in a 24 inch mono hull boat.. Running on the water it leans to the right, if you don't let off soon enough it will flip over to the right and land on its top. I'm sure you are a busy man but as I am 75 years old and just learning, and don't know anyone else interested in th rc boat hobby. I am sort of a a loss for information sources. Thankyou and all the others that help on youtube. The transom I copied off a udi005. I just bought all the replacement parts for the udi005 and used them. You might be familiar with the boat I used , it is a old harbor freight boat called the Neptune. I just gutted it and then put in all new everything.

@RCexplained

2 жыл бұрын

Hi William, they may say the RPM is 50,000 max, however this does not work well in boats if ran at 50k RPM. Boats perform best at a max of 33 to 35k RPM for yhe average boater. Higher if racing and experienced. What the motor states as a max rpm is not necessarily the RPM that the motor is actually going to run on. This is controlled by who is selecting the power system based on Kv and battery voltage essentially. 3100Kv with a 2 or 3 cell LiPo can work OK. However I would not recommend a 4 cell LiPo.

@williamhendricks2078

2 жыл бұрын

@@RCexplained thankyou so much! I will take your advice.

Ive had this issue in aces. I wish you could help me out with my airboat. Finding a good balance for RPM/Blacdes/Pitch and Weight has led to many rebuilds, sunk boats and lots and lots of flip overs.. Its getting good, but still needs a lot of help. This video shows the most recent test run. kzread.info/dash/bejne/qqOd0pJupc2WYLQ.html

@RCexplained

3 ай бұрын

What's your length and width. Is the ratio of these calues somewhere around 2.4-2.6?

@PaulKind3d

3 ай бұрын

@@RCexplained 29" x 8.875" is the dimensions. so.3.26 is the ratio....

@PaulKind3d

3 ай бұрын

i had a shorter length at first, but found the bow slap to be so bad i lengthened the design. That bit seemed to have substantially helped the performing characteristics... It immediately took turns more predictably.

@PaulKind3d

3 ай бұрын

improved but did not eliminate bow slap.

@RCexplained

3 ай бұрын

@PaulKind3d I'd expect that the ratio of length to width is a bit high. Maintaining a ratio closer to 2.6 will help. Overall making the airboat larger in both dimensions helps with stability. Take a look at common airboat on the market for an idea on this ratio.

The faster my motor spins the boat loses speed. I can walk faster than it is going. Why Is this?

@RCexplained

Жыл бұрын

Sounds like it's catching a lot of air. What are all the specs? Motor, battery, boat, prop

@justinwalker923

Жыл бұрын

@@RCexplained 80 amp esc 5200kv on 2-3s, 100c. Two blade 35mm aluminum prop. Not sure the pitch. The shaft is angled below the boat hull. I built this boat myself. The boat is 29" long fiberglass so it's not heavy.

@justinwalker923

Жыл бұрын

@@RCexplained it acts like the faster it spins the less thrust. Cant run at full throttle the boat barely moves. All connections and linkages are tight and firm.

@RCexplained

Жыл бұрын

@justinwalker923 sounds like a lot of RPM requiring a small prop. A 29in hull is better suited to a prop of at least 40mm, however your setup won't like this as your Kv is a bit high.

@justinwalker923

Жыл бұрын

@@RCexplained so I guess its kinda like rc cars/trucks. Lower kv and larger gears... Lower kv and larger prop...