TP 4050 1950kv on 6s

[CraigP]

Thanks for responding and let’s just drop the runtime thing... I hope going thru the math showed you some tools you can use. So, let’s start at the beginning. Looks like you want to sport boat, no racing and desire a fairly fast and reliable setup. The first thing to consider is that the racers are constrained to use low voltage, high amp setups due to class rules. So addressing the reliability aspect, it’s amps that kills parts. As long as the ESC and motor have a voltage rating of at least 6s, then running that voltage will require lower amps, keeping all else the same. Mainly, it’s prop size and speed. So if you want to use 30,000rpm (a good, fast number. Lends itself to smaller prop/faster rotation mind set), then you choose a motor to achieve that result at the desired voltage. So, 30000/22.2= 1351kv. There is a TP4060, a good motor, with a 1350kv. I run a Leopard 4082, 1250kv in a Skater32 Cat and it’s ample motor. You’ll be a bit slower than the target 30,000rpm. On batteries, if you’re running higher voltage and lower amps, then you don’t need top quality batteries, you can live with higher internal resistance.

So you need to decide for yourself what you desire. Hopefully getting some info will help you. I have a lot in common with you, want a fast boat, not racing, and willing to look at out-of-the-box solutions to hold my cost down and still have good reliability.

[R2315]

I been using the 420's and they have been great so far and I like that I get the castle connectors already on them.

http://www.store.revolectrix.com/Products/Blend420-SILVER-Label-70C-GOPACKS/Revolectrix-5000mAh-3S-Lipo-70C-Silver-Label-GOPACKS-GrapheneOxide-Edition

[R2315]

And if a certain Kv, or prop does'nt end up being for you then off to the swap shop you go and your probably not out to much $$ in the long run. Better to work up to it I guess then going all in.

[danzuby]

Thanks Craig for your help I'm gonna stay in the 1550-1750kv range I'm kinda liking 4060 1750 with an X645 I don't think I can get away with the X648 on that motor but I will have to do some more research. I'm not dead set on anything yet and I probably won't do anything til this motor starts to get weak. What prop are you turning on your 1250?

[danzuby]

Yep your right R2315 I figure Im at 1800kv now and its ok but I cant prop up to get the few more mph I want so a little bigger on the motor in the same kv or close to it should do the trick but if not back to the drawing board and hello swap shop lol.

[kfxguy]

I’ll be trying roaring top soon. I used to use revolectrix.

[CraigP]

Thanks Craig for your help I'm gonna stay in the 1550-1750kv range I'm kinda liking 4060 1750 with an X645 I don't think I can get away with the X648 on that motor but I will have to do some more research. I'm not dead set on anything yet and I probably won't do anything til this motor starts to get weak. What prop are you turning on your 1250?

I’ve got a 1816-17-45 ABC prop on there. So you’re going to use 1750kv on 6S? 38,800rpm... sounds like you want to hit 75mph with the boat. I recommend you listen to these guys on battery selection, because you’re going to need it.. I’m not the best source for info on a zip-zip setup, so I’m going to respectfully bow out.

Im sorry, I made a mistake... I have a 1450kv on my 6s Skater32. The prop is right...

[CraigP]

On battery, I’m using two, HRB 6S, 5000mah in parallel, for 10,000mah total capacity. I’m running about 6 minutes to 25% left in the batts. The batts have been very good, bought them from someone on the forum. They’ve been charging and balancing great, and holding their IR values.

[danzuby]

The stock motor that's in there now is 1800kv on 6s and I'm only at 56mph with 42mm prop so I'm not sure how I will hit 75 with 1750kv and a 645 prop.

[CraigP]

You’re 14mph off the speed calculator, using conservative efficiency values so you got other issues. Either your electrical system is not delivering the expected power or your hull/setup efficiency is really low. Maybe you should start there? You should be able to hit 70 with your stated setup. All I know is all 5 of my hulls run within a couple of mph of the calculator... The first hull didn’t, I was about 10 off, so I learned more about it and got it up to where it should be.

[danzuby]

The calculator I'm using is at radiocontrolinfo.com and when I put my current setup in 1800kv, 6s, X642, and cat hull it says 59.4 mph , 39,000 unloaded rpm and 33,000 loaded rpm. What calculator do you use?

[CraigP]

There’s a calculator on this site, at the top, called Speed Calc. You put in the kv, then the motor efficiency. I used 88%, most BLDC motors are 90. You put in the number of cells, 6 in this case, then the cell voltage. The default is 3.7V which is a good, loaded value. You enter the prop itch, in this case, 1.6 and the diameter in mm, which is 42. Then, there’s a hull efficiency number. Cats up on a good plane and riding free are close to full bodied hydros, which is 20%. Riggers are 15%, the most efficient hull in RC. So that gives 70mph. I like this, because if you don’t hit your numbers, you can adjust the efficiency numbers independently and get to the root of the problem. Anyway, it works for me and many experienced people here on the site. And these results match my own calculations.

[danzuby]

Very cool thank you so much. I will check it out.

[Mxkid261]

I run a TP 4060 1720kv in a 32” fightercat. Its a lot of motor on 6s and will push a t-180 over its limits if you’re not careful. Curious what boat exactly you are running or did I just miss that?

F966377D-717B-4086-9F55-F08EEE321EFC.jpeg

[R2315]

I run a TP 4060 1720kv in a 32” fightercat. Its a lot of motor on 6s and will push a t-180 over its limits if you’re not careful. Curious what boat exactly you are running or did I just miss that?

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mmmmmm... crispy esc.... I was going to suggest maybe upping the esc and it wouldn't hurt to invest in something to log with while experimenting with props, just to know where you stand.