Number cells/Motor Kv/Prop Size/Hull Size

[ReddyWatts]

What about a spreadsheet to help users decide on a build?


"Updated" with Lipo and esc amp ratings. There are too many variables for this to be exact for all of the different hull and motor loads. Many setups will fall outside of this general data spreadsheet. Just hope this gives you a better understanding of FE for designing successful setups.

--hull size /--------Cells---------/ ----Motor Kv----- / -------Prop Size------/---Type ESC---/-BEC-/ESC Amp Rating

17”- 24” / 2s LiPo or 6 cell NiMh / 5500 -3200Kv / 30mm - 40mm Diam. / Low Voltage / Avail. / 120 amp

20"-27" / 3s LiPo or 8 cell NiMh / 3500-2500kv / 35mm – 42mm Diam. / Low Voltage / Avail. / 120 amp

24”-29” / 4s LiPo or 12 cell NiMh /2650-1600Kv /37mm - 46mm Diam. / Low Voltage / Avail~Disc / 120-240 amp

26”-32" / 6s LiPo or 18 cell NiMh /1800-1100Kv /40mm - 52mm Diam. / Low or High / Disc. / 120-180-240 amp

30"- 36" / 8s LiPo or 24 cell NiMh / 1350-800Kv /45mm – 55mm Diam. / High Voltage / N/A / 180-240 amp

34" - 42" / 10s LiPo or 30 cell NiMh / 1100-600Kv /47mm + Diameter / High Voltage / N/A / 180-240 amp

38" - 46" / 12s LiPo or 36 cell NiMh / 900-550Kv / 50mm + Diameter / High Voltage / N/A / 240 amp

Always start testing with a small prop and work up to your desired amp readings!


HULL SIZE AND OSE MOTORS

This is a general guideline for the motors OSE sells. I know it is hard for this to cover all selections, since FE setups can be complex and extend over a wide range of extremes. Remember this is more for conservative setups to help new guys get started.

hull size…..... /…...... Neu….... /….. Feigao.540…../Feigao 580/...700SC../.SV27./.Proboat./..Ammo../.380.

<<"-20"....../.....1506........../.......Fiegao.S......./................./................./......../............../.............../.380 L

17”-24”…../….. 1506,1509./…..Feigao S-L…...../…............../................./......../............../................/........

20"-27"…../….. 1509,1512./…..Feigao L-XL...../….............../...700SC../.SV27./.Proboat./..Ammo../........

24”-29”…../…..1512,1515../…..Feigao XL…...../….............../...700SC../.SV27./.Proboat./..Ammo../.......

26”-32"…../.....1512,1515../…..Feigao XL….../….............../.,..700SC../.SV27./.ProBoat./............./........

30"-36"…../….. 1515,1521./…........…………..../….. 580L...../.............../........../.............../............./........

34"-42"…../….. 1521,1527. /…........………..…/….. 580L...../................/........./................/............./........

38"-46"…../…..1527,2215. /….. ......……..……/................../................./........./................/............./........

40"-60"..../.......2230......./Little Screamer 63mm outrunner/

MOTOR MAXIMUM WATT RATINGS.

Always look at the maximum WATTS the motor is rated to handle. The heat will kill the magnets and possibly the controller if you get it to HOT.

Continuous rating/ 30 second rating

Neu -
1506 - 700 watts/ 1500 watts
1509 - 1000 watts/ 2000 watts
1512 - 1200 watts/ 2500 watts
1515 - 1500 watts/ 2700 watts
1521 - 1700 watts/ 3000 watts
1527 - 2100 watts/ 3300 watts
2215 - 3000 watts/ 5000 watts
2230 - 6000 watts/ 10000 watts

Feigao
580L - 1800 watts/
540 XL - 800 watts/ 1600 watts
540L - 600 watts/ 1300 watts
540S - 450 watts/ 1000 watts
380L - 450 watts/ 1000 watts

SV - BlackJack 800 watts/ 1400 watts

Ammo 2300 - 700 watts/ 1400 watts

700sc - 650 watts

Volts (X) Amps = Watts

Always calculate your setup Watts and prop it to run close to your motors Max Amp rating. (maximum effeciency rating)

Example:
Specs for the motor in the BJ
TURNIGY brushless Inrunner

Power: 460W
Battery Config: 3-5S

Watts / Volts = maximum AMPS to keep motor cool - recommended by manufacturer.

460 watts / 11.1volts = 41.4 amps max

460 watts / 14.8 volts = 31 amps max

460 watts / 18.5 volts = 25 amps max

FeCalc can get you in the ballpark for loaded 2-pole motor watts and amps. It is just an estimate, but can give you a good idea of which prop to start testing with.

[ReddyWatts]

I like to try and simplify things to make brushless FE easier for the next guy.

Very few people have experience with all of the setups. Need some input.

Thanks, Reddy

[tth]

Good Job Reddy That's Going To Help A Lot Of People Simplify Things. I Know I Have Learned Much Needed Info From This Site. Granted I'm Thirty Yrs Old I Have Been Building Boats For Fifteen Yrs. A Little Over A Yr Ago
I Started To Get Serious In The Boating Community. Again Thank You To Everyone That Has Helped Me In My Builds And Answered My Posts. Keep Up The Good Work Everyone.

[G Doggett]

Great idea Reddy.
Good basic information to use as a starting point.
What ever happened to the suggestion a while back, I think from Steven, for a spreadsheet of set ups that we are running that work ?
This sort of shared info is valuable even for old farts like me who have been building boats for years.
Graham.

[Eyekandyboats]

yes
36 inch hull run 4s on a 50+ mm prop

[ED66677]

Can't be more clear! Great job!
I'm personnaly just a little bit out of the table but soon will be back on proper track!!! 29" on 3S, soon 4S!
Wouldn't it be helpfull Reddy to indicate an average amp draw for each? I mean if a new guy want to go fast with a 29" mono he first need to know that this will not be possible at 30amps but pretty much at 60-80+amps... just my thought!

[ReddyWatts]

Ed, I will start looking into your idea.

Eyekandy, what is the rest of your setup?

Graham, I have been wondering the same thing about Stevens setup sheet. He has probably just been to busy.

[Eyekandyboats]

--hull size /-------------Cells---------/ -Motor Kv--- / -------Prop Size---------

17”- 27” / 2 cell LiPo or 6 cell NiMh / 600 -3200Kv / 27mm - 46mm Diameter

20"-27" / 3 cell LiPo or 8 cell NiMh / 3500-2500kv / 35mm – 46mm Diameter

24”-34” / 4 cell LiPo or 12 cell NiMh /2650-1200Kv /35mm - 55mm Diameter

26”-40" / 6 cell LiPo or 18 cell NiMh /1900-1100Kv /35mm - 52mm Diameter

26"- 40" / 8 cell LiPo or 24 cell NiMh / 1500-800Kv /37mm – 55mm Diameter

30" - 44" / 10 cell LiPo or 30 cell NiMh / 1100-600Kv /37mm + Diameter

34" - 50" / 12 cell LiPo or 36 cell NiMh / 900-450Kv /37mm + Diameter

[ReddyWatts]

Thanks for your input Eyekandy.

That must be a typo on the 600 kv and 2S or 6 cell


37mm prop on a 12 s lipo- 36 cell NiMH, 34 -50 inch hull???

[hex-dj]

Great job Reddy. Now I can have a much clear idea about the setups.

[ReddyWatts]

Thanks, that is what I was hoping to accomplish by showing a simplified "Big Picture".

[Eyekandyboats]

Thanks for your input Eyekandy.

That must be a typo on the 600 kv and 2S or 6 cell


37mm prop on a 12 s lipo- 36 cell NiMH, 34 -50 inch hull???

yeah sorry it was supposed to be 6000

and yes

[sdartt]

When you call for a 26 to 32 inch hull using 6 cell LiPo's, does that mean 2 packs with 3 LiPo's each. Thanks for the reply!

[ghostofpf1]

Very helpful.
Something I had wished more of the vendors would do is give specific power source range recommendations for their hulls.....props..motors kv and mass...amp ranges for each set up.....
Second on the ~amp draws btw..this would be very helpful in spec'ing power components.
thanks much
Ghost

[Eyekandyboats]

also you BEC idea.. good but.. BEC should not be used on any model unless its a micro. you get better results with a BEC pack.

do you race under IMPBA or NAMBA ?

[sunsation288]

Just one word , THANKS , for share all your knowledge guy , its realy appreciated....
Regards
Christian

[ReddyWatts]

Sunsation - thanks, but can't take full credit for this. Got the idea for a condensed spreadsheet while reading on another forum.

[ReddyWatts]

Sdart - You can use it either way. It is your preference, two 3S or one 6S. Whatever will work best in your hull or charger.
Eyekandy - Neither and I think that BEC is a user preference.
Ghost - I agree, but it is something they would have to keep updated since FE is a fast changing hobby. I am going to look into the amp ranges for the spreadsheet. Steven is supposed to be working on a forum spreadsheet we can enter our setups, to share with everyone.

[DISAR]

Nice work! In my opinion, these are general guidelines and one thing that is missing is estimated speed. For example for a 36" hull what is the speed with 8s, 1350 kv and 45 mm prop? Is it the same with the 800 kv and 55m prop?

Another think to mention is that I have a 36" mono running on 4s, 1700 kv, 45 mm prop, 100a ESC and runs around 35 mph.

[Steven Vaccaro]

Nice job.

[ReddyWatts]

Steven, thanks.

Disar, I will look into adding the general speeds to be expected from the different setups.

Ed, updated the spreadsheet with ESC amp ratings.

[DISAR]

Hi again,

Based on your values I prepared an Excel sheet as attached. This is for the 26-32" hulls but can be used for any of the sizes. Just insert the values in the blue boxes according to your values and it gives the required propeller according to the actual Kv and cells fitted on the boat.
This spreadsheet may be very simple and unuseful but I prepared it to see where I am standing and decided to post it.
Thanks for your valuable info.

[DISAR]

Let me correct previous spreadsheet , has one mistake in the chart view. This is the correct one.

[ReddyWatts]

Disar, can you explain more details on how to use the spreadsheat? Maybe give some examples.

[DISAR]

From the values you gave, for a specific hull size and specific lipo cells, a line is drawn (as in the chart) connecting point1* to point2**. Then somebody can insert his values( lipo cells and motor KV hence RPM) and find out what propeller diameter is needed. In other words, once the line is drawn (from your posted values) then you enter with the actual RPM and it gives you the prop.diameter (the method used is called linear interpolation in maths).

*point1: high Kv with small prop.diameter
**point 2: low Kv with large prop.diameter

For example for the 26-32" hull, you enter the following values:
In cell (a): Hull size (26-32)
In cell (b): Number of lipo cells (6)
In cell (c): High Kv (1800)
In cell (d): Low Kv (1100)
Cell (e) : Do not enter anything. Calculates RPM for the 1800 Kv
Cell (f) : Do not enter anything. Calculates RPM for the 1100 Kv
Cell (g): Small prop Diam (40)
Cell (h): Large prop Diam (52)
Cell (i): Enter Kv of your motor installed or to be bought (2900 for example)
Cell (j): Enter lipo cells that you use (3 for example)
Cell (k): Do not enter anything: Calculates actual RPM of your boat
Cell (l): Calculates propeller diam required (46mm for example)

According to the spreadsheet, I also prepared the following equations which for each boat hull size give you the propeller diameter according to your posted values:

17-27" : Prop Diam = -0.0006*RPM+53.913
20-27" : Prop Diam = -0.0006*RPM+59.5
24-29" : Prop Diam = -0.0006*RPM+59.714
26-32" : Prop Diam = -0.0008*RPM+70.857
30-36" : Prop Diam = -0.0006*RPM=69.545

The setups seem to be very high specs I would say racing giving high speeds I suppose.
I tried also with Eyekandyboats values and for my boats I got same results as my boat tests, using the 24-34" hull size with 4 cells Lipo values. The speeds for a 32" (2900 kv, 3s, 42mm) cat and 36" mono(1853kv, 4s, 45mm) are about 35-40 mph.

Thanks

[ReddyWatts]

Disar, thanks.

[ED66677]

that's really nice!
Has to be part of the holly FEB bible!

[DISAR]

A final comment is that I used the program with your posted values for the 24-29" hulls with 4s, for my boats and setups and the results are right on target.

32" cat (2900 Kv, 3s, 42 mm)
36" mono (1853 kV, 4s, 45 mm OR 1700 Kv, 4s, 45mm)

I have no experience with 6s and upwards setups and I cannot make any comments.

[DISAR]

Hi again,

Based on all the above I prepared the attached Excel file for calculating the prop diameter for each hull type and giving the setups. There are two sheets in the file one with the ReddyWatts values and one with the Eyekandyboats values.
The layout is:

17-24" Hulls, 2 cell Lipos
5500-3200 Kv
Please enter KV & number of Lipos
Motor KV 3200 ------------Here you enter the motor Kv
Lipo Cells Number 2 ------Here you enter to Lipo cells number

The required propeller diameter is
Prop Required 40 ----- Calculates prop diameter

[ReddyWatts]

Thanks again Disar

Remember, there are to many variables for this data to fit all the different hull and motor loads. Many setups will fall outside this general information spreadsheet.

This was mainly to show a structure of setups so you will see the "Big Picture" for a better understanding of FE.

Always start testing with a small prop and work up to your desired amp readings!


.