Help! what is wrong with my setup???

[boilo56]

Hi, I just got back from running my HK Pursuit boat, and i tried 5s and for the first time 6s on the stock prop. 5s got me to 59kph, and 6s got me to 61 kph. According to the OSE speed calculator, i should be around 81kph. So what can be wrong here? Esc is mamba monster2, stock motor and prop.

Thank you for your help!

Andre

[Peter A]

Problem is the stock prop! That aquastar motor you are looking at and an x442 on 4s should have you in the 70 kph range easy. I gps'd that motor with x442 in a rigger at 86kph.

[boilo56]

Ok, i'll change the prop, i have an Octura x442, but the shape of it looks weird...IMG_20150524_155851.jpgIMG_20150524_155914.jpg
Is that shape normal for this prop?

[Doby]

First off, don't take the speed calculator as gospel...there are so many other contributing factors that can affect boat speed.
Second, that looks like a raw prop...balance it first.

[boilo56]

First off, don't take the speed calculator as gospel...there are so many other contributing factors that can affect boat speed.
Second, that looks like a raw prop...balance it first.

Hi, i didn't take the speed calculator as gospel, i know it only gives a general result. but it gives an idea of where you can be. But the speed a got was like 20kph below... 6 to 10 kph, ok, but 20? And yes, that prop is raw. I don't know how to balance a prop, that is why i still use the stock prop.

[Peter A]

The stock prop that comes with the pursuit is a very detongued 442. That is why the x442 looks so different. Search through the prop talk threads for info on balancing props, but if you want something already done then try Dasboata to do these for you or buy some finished props. Check out the OSE store for those.

[boilo56]

Actually, it looks like it is detounged and backcut. See it compared to the x442 and the grimracerIMG_20150524_193000.jpgIMG_20150524_193008.jpgIMG_20150524_193032.jpgIMG_20150524_193051.jpg

[Make-a-Wake]

5s got me to 59kph, and 6s got me to 61 kph. According to the OSE speed calculator, i should be around 81kph. So what can be wrong here?
Thank you for your help!

Andre

The problem is the stock motor isn't powerful enough to spin that prop on 6s............5s is making it struggle as well.

Get the 3974 you are looking at.

[Turbo Dan-O]

The problem is the stock motor isn't powerful enough to spin that prop on 6s............5s is making it struggle as well.

Get the 3974 you are looking at.

I don't know. I have the same boat with the same 1620kv SSS motor. It's a good running motor! Mine went 33 mph with the stock prop(S/B) and "looks" a good bit quicker with an m445 on 4s.

[Make-a-Wake]

I don't know. I have the same boat with the same 1620kv SSS motor. It's a good running motor! Mine went 33 mph with the stock prop(S/B) and "looks" a good bit quicker with an m445 on 4s.

So running the same motor and prop you got 33mph............he got 36 on 5s, a 9% speed increase is very minimal for going up one cell, and then 6s got only 1 more mph. The motor is already straining on 5s..............6s will fry it on a 5 min run.

[boilo56]

Hi again, i think i may have found what was wrong. I just checked the batteries i was using for the 6s passes, and i found out that a cell of my 2s has gone bad. it doesn't keep the charge. so the LVC might have kicked in cause of the voltage drop. I will make more testing sometime this week and i'll give you update soon.

[Turbo Dan-O]

Boilo, did you tweek/gps it any on 4s? Make-a-wake is probably right. Still seems weird to me but I'm still learning this stuff... And yes, that thing is going to smoke on 6s!

[boilo56]

Boilo, did you tweek/gps it any on 4s? Make-a-wake is probably right. Still seems weird to me but I'm still learning this stuff... And yes, that thing is going to smoke on 6s!

Yes i did gps it on 4s, i got +/- 48kph.

[boilo56]

Hi again, i have done some testing, on 4s and 5s. I tried the x442. 4s=52kph & 5s=60kph. my batteries were good for the 5s. But i still think it is slower than it should be. could it be the motor dying? According to the speed calc, it should be around 70kph. I know, don't take the result for cash. But still it gives an idea of where it should be. I've played with the data input, and to get to 60kph with my setup on 5s, either the motor efficiency is less than 80% with prop slippage at 25% or, 90% motor efficiency and more than 30% prop slippage... I'm totally lost here... Anybody have an isea?

[tlandauer]

Hi again, i have done some testing, on 4s and 5s. I tried the x442. 4s=52kph & 5s=60kph. my batteries were good for the 5s. But i still think it is slower than it should be. could it be the motor dying? According to the speed calc, it should be around 70kph. I know, don't take the result for cash. But still it gives an idea of where it should be. I've played with the data input, and to get to 60kph with my setup on 5s, either the motor efficiency is less than 80% with prop slippage at 25% or, 90% motor efficiency and more than 30% prop slippage... I'm totally lost here... Anybody have an isea?

I have a 4082/2200kv running 4s2p and with a M445 mine is GPS'ed at 46 mph=74kph. I have not fine tuned it, it came straight from the previous seller. My boat has expansion foam and the COG is bow heavy, so this is actually a "wet running" boat, I bet there is more if I adjusted it better. Your speed should be faster as you said. Is your ESC 's throttle curve calibrated correctly with your transmitter?
What motor is in your stock boat?