Recomended RPM range explained

[emspjay]

I'm new to all this FE brushless stuff but I am learning from you guys about it and about proper boat set up also. You need to properly set up your drive angles as well, I think I burnt up the original HK 120 in my Genesis dues to the hull running too wet (bow down too much, not sure if that is negative or positive and the drive angle). I changed my drive angle as suggested on here and never burnt up another ESC but I did switch to a 180 after burning up the 120. I don't know much except for it seems like there is a lot of variables in getting a good reliable running boat. Not just how big your batteries are and what KV your motor is. I have been following advice I got on here and I have a great "sport" running Zonda, I love it! It is fast and reliable for the sport running I do.

[Speed3]

One thing I forget to mention even with those rpm guildline becareful not to over prop.

For the sport boater I think a 42mm prop example x442, x642 or smaller with the 25000 total rpm is a safe guild line setup.

[Prodrvr]

Crash, what are your speed goals?

[Alfa Spirit]

Look at this Twin setup Genesis, 2 x Scorpion 3026 - 1400kV and 7S

36000 RPM unload.

https://www.youtube.com/watch?v=o3KCKjPuZkc

[M3Bluegsr]

Here is a Tenshock Electra twin setup 2 x 2200kV and 2 x 6S

Adding a second motor reduces the load each one sees..

[Crash]

Crash, what are your speed goals?

70 mph was my goal , I hit 68mph recently before a blow over.
I ordered a 94 mph prop to play with someday, I dont have it yet. Octura 2352
its just for a speed pass, i dont have any idea how many amps a 4.7pitch prop will draw......lol

my set up is two 5s lipos parallel with 1750 kv and a 52mm prop

[Alfa Spirit]

2 x 5s lipos and 1750 kv motors ok but what is your hull ?

[Crash]

36 inch mono
its heavy loaded up with lipo rtr it is 172 oz.

[785boats]

Crash.
Here's a chart that shows good numbers for oval & sport running if you stay in the red band.
For the 'point & squirt' type of running you can go a bit higher in the kv.
Motor KV_Batt.jpg

[Crash]

Crash.
Here's a chart that shows good numbers for oval & sport running if you stay in the red band.
For the 'point & squirt' type of running you can go a bit higher in the kv.
[ATTACH=CONFIG]161421[/ATTACH]

thanks for that.
I wonder if this set up would like 6s better due to the weight of this boat, I am running a 52mm prop to get this boat to move like I want it to. at that size prop I am drawing 275 amps on flat water 100% throttle at times.

more volts may bring the amps down …..?

[T.S.Davis]

The problem I have with all these high rpm recommendations is that this forum gets a ton of lurkers. Nothing wrong with that really. Read read read. You can learn a ton just with the search tool. So new guy comes here reads basically "if you want to go fast, go with gOzillion rpm. Screw the racers they don't know anything" All he hears is "fast". "I wanna go fast fast fast".

So he builds a 2000kv 6s boat with no idea what's what. Gets the gap on the drive dog wrong. Maybe has an imbalanced prop. Struts the wrong depth. Or maybe he gets the CG wrong so it runs super wet. Even if he gets it all right he may run it for 8 minutes. Burns the whole thing to a crisp and we never hear from him again. He's out of the hobby.

[785boats]

Totally agree Terry.
Burnt a 4082 2000kv motor myself in a 33" mono. A well trimmed 4s race boat that I decided to try on 6s with a smaller prop. It lasted only 3 laps.
Mind you, it was only a Leopard motor though.

I'm trending to run lower kv motors lately.
My twin cat runs HET Typhoon 650-68-1600kv motors. Originaly built as a 6s class boat with 4214/3 blade props.
But I also run it in our 4s class with 4718/3 blade props.
It beats the cats running much higher 2200 plus kv motors.
Under our rules both motors must run off the same single 4s pack. I still have 30-40 percent left in a single 6000mah pack after a race.
Fast & efficient.

[Prodrvr]

33 1/2" mono, 6s, 2000Kv...runs full throttle for the entire pack, nothing comes back hotter than 130. AQ Motley Crew...6s 2075Kv...would run 4 full throttle passes...nothing came back hot. I agree that a new boater burning stuff up from the get go will make them give up. However, if they educate themselves first and move up gradually, they'll have a boat that does what they want.

[Prodrvr]

I ordered a 94 mph prop to play with someday, I dont have it yet

A whaaaat?

[TRUCKPULL]

A whaaaat?

John

It looks like he has ordered a Octura 2352
52mm - Dia
2.3 pitch ratio = 120mm of pitch

a Octura 452 is only 62mm of pitch

He is now drawing 275Amp with a 452
2350 Prop - he would need 140 C batteries and a 500Amp ESC. and watch out for the

Larry