Full-p JAE

[HTV Boats]

Im not speaking from experience mind you but its only a 6% increase in kv I doubt there will be any significant differenve between 2200kv and 2340 . Apprx 32.5k vs 34.6k. Give or take a 2K!!!! @ 4s.

You might consider 2K not a significant differance but in a heat race it might make the difference in winning or loosing. The other factor here is the 1515 is a Y wind and peak rated at 2500watts, where the 1518 is a D wind and rated at 3000watts peak so there will be a significant power draw difference. I am hoping someone who has run both the 1515 and 1518 will chime in.

Mic

 

[hugh hargett]

OK but all i see is apprx 34 amps difference @ 4s lipo . At the same amp draw the motor with the lower kv will have more torque.

This is proven by

1/kv = kt the torque constant of that motor

kt multiplied by amps give you the torque of your particular motor.Then all you need to factor is which motor at it max efficient amp draw will deliver the most turning force.

Good luck in your search but typically the motor with more torque can pull the heathier prop in turn move the boat faster.. You really dont have to be a racer to figure out whats going on with electronics Mic.

Youd have to pull 203 amps at 4slipo to get too 3000 watts something i dont think youd want to do with a sf200 .U dont want to run at max wattage for heat racing anyway.

just trying to help but if you dont want it thats quite cool. Happy boating!

Later.

 

[Scott_T]

I am hoping someone who has run both the 1515 and 1518 will chime in.

Mic

Without derailing this thread too far, I have run both motors in my DF33 mono. Put simply, the 1518 will swing a bigger prop than the 1515, at higher rpm (and draw more current accordingly). The 1518 is getting beyond the limits of my DF33 (or maybe my setup ability). And it does all this while running nice and cool. It is a beast of a motor.

MIne actually doesn't draw much more mAh than the 1515, probably because it's operating more efficiently at the current we draw. It might not be better than a 1515 in every application, but if you're looking to buy another motor, definitely give one a try.

 

[hugh hargett]

Scott Im confused if you are drawing more current with the 1518 how could you be pulling less mah? :huh: Efficiency wont change a thing in this case current draw is current draw the battery doesnt know if the motors efficient or not all it knows is its hungry.

 

[HTV Boats]

I am hoping someone who has run both the 1515 and 1518 will chime in.

Mic

Without derailing this thread too far, I have run both motors in my DF33 mono. Put simply, the 1518 will swing a bigger prop than the 1515, at higher rpm (and draw more current accordingly). The 1518 is getting beyond the limits of my DF33 (or maybe my setup ability). And it does all this while running nice and cool. It is a beast of a motor.

MIne actually doesn't draw much more mAh than the 1515, probably because it's operating more efficiently at the current we draw. It might not be better than a 1515 in every application, but if you're looking to buy another motor, definitely give one a try.

That is what I was looking for as my DF33 has the 1515/2200kv as does my P tunnel Shaman. Looking for a little edge without going to a 1524-1D/2550 and the battery a controller it would need. If you don't draw a lot more ma's it may have to do with a D wind over a Y. Or just airing out the boat and covering distance in a shorter time period. What prop are you running on your DF? I heat race an M445 and M545. I also have a 2200kv 4092 TP that has a lot more grunt than a DF needs but eats power pretty hard. At any rate my next P motor will probably be the 1518/2340.

The only other option would be a 1520 1D but at 2900kv more of a SAW motor. Thanks for the info.

Mic

 

[hugh hargett]

Draw is draw if you pull more you take more from the battery. D or Y wind no matter if you draw a current that current pulls the battery down. More current more pull from the battery. Anything else Id be real interested in seeing please share it. This is not a IMHO this is OHMS LAW! be mindful. For what you say to be possible you had to have left something out in your previous post. What was it?

Scott,were you indeed pulling more current with the 1518? If so ...... :huh: pulling less AMP capacity on the same battery makes no sense. How did you come to this conclusion?

 

[HTV Boats]

Years ago in my military days I spent 2 years in electronics schools working on counter mortar radar and the computers that ran the system. Probably could fit the system in a calcutator today. With all the laws of physics and electronics when you get in the field things just happen that defy logic. Boats have so many variables especially with hull hyrdodynamics and propellors that you learn as you test things are not linear. Kind of like looking for that sweet spot in a tune pipe. This is why we share info here as no book gives what on the water experience does.

Mic

 

[hugh hargett]

Scott? Pm me dont wanna take the thread outta context ill just start another. Joe good luck with your boat and watch the new thread coz I gotta have a real explanaion coz if you claim a certain amp draw at a certain voltage youve committed yourself to ohms law forget hydrodynamics and all that stuff which too is learned in a book and through expirement and study.

I must admit I cant wait to see where and how this "magic" was created as well as how it was measured.

Prop, hull drag; all incorporated into one measurable number in this instant - amp draw.

happy boating Joe, Scott hope to see you chime in on the new thread.

Later

Hugh

 

[hugh hargett]

My bad scott RP cleared it up you said "doesnt draw much more" which goes back to what I tried to say in the first place I dont think that a 6% in kv or a mere 34 amps increase would lead to much difference . If those two motor are of the same physical dimensions they should perform closely alike a d wing has more power and rpm than a y(WYE) @ the same number of winds. But these are of two different winds which will bring them closer back to equality in power but just a different KV. 500 watts a bit less than a hp @ max ratings. But as I stated you wouldnt want to race at max ratings. Rms power would be be somewhere in the neighborhood of 1700-2000 watts for those two motors or 114-135 amps with a peak of around 190 amps. water/air colling allow you to push a little harder. Efficiency(a good heat killer) can be improved with the right timing setting. 0-7.5 for d's 7.5-20 for wye's

on the term power

Hp is not what turns a prop torque is. While a motor may have more power that does not meant it has more torque you have to go deeper than that. Rpm is speed relevant of course but you have to have the torque to turn your "dream" prop at that rpm you so desperately want. In Fe what ive seen is a decrease in prop diameter because the torque of a nitro wasnt present to turn the same prop at the higher dream rpm. proof

a nue 15271y has about the same HP(but more rpm) as a .90 but it cannot turn a prop as big. From my friends that are top LEVEL CLASS RACERS THEY WILL TELL you that the smaller prop will suffer in "race" water . Supposing you had to prop down the 2340 kv motor to keep the amps reasonable theres a point where the 2200kv is going to perform better especially in "race" water for cavitation and blow out issues.

A 2028 has near twice the hp as a nitro 101 just to be able to turn a prop of the same diameter and pitch at its higher rpm! Torque mean ALOT TOO!

At the end of the day it comes back to alot of testing to find the right prop for what you wanna do! Its probably not a good idea to be testing prop in a "race" better already know by then.

 

[RonShaw]

E(voltage)=I (current) x R (resistance)

E/I=R

E/R=I

W(watts)= I (current) x E (voltage)

W/I=E

W/E=I

You can take those to the bank. Only variable tough to determine with calculations is RPM, which is affected by the load on the motor. That's where RPM sensors come into play.....

 

[hugh hargett]

I was taught two things - you need to help find the prop is the rpm via data logging, speed sensor, or audible tach, and a radar gun ,or a way to reliably measure speed. Finding a good prop that lets the motor function at the upper limits of the rpm range should give you less load and a good power band.

 

[JoeWScott]

I'm going with a limited, p-spec steup. Lets here it? Aquacraft all the way!

 

[hugh hargett]

AWW you told a fib you said full p I thought you were going to buy a castle motor????

 

[JoeWScott]

4 minutes Hugh that's impressive!!LOL Well after much deliberation, I think it will be best to "get my feet wet" or boat, starting with a Spec boat. I'm new to this electric stuff. Have heard of good reliabilty, affordability, run time etc... wit the spec stuff.

 

[hugh hargett]

Yes it a good way to get your feet wet but youll see its limitations when you really want to start cooking a plmtd set up is underpowered in that Jae hull . If you can go with another esc besides AQ in your district Id do so so when you step into the leo WHICH YOU WILL you will already be ready.

dont think coz i havent posted im not still here. Im always present in FE bro. LOL you guys have been quiet lately so im playing with the nitro guys right now.

 

[Chilli]

Many of the guys that run P-Limited class with open controllers are using 120 amp controllers. Anything more than that is dead weight and we all know those controllers are not going to cut if for P-Hydro. In racing conditions, the UL1 gear is a great match to the JAE FE. If the boat was designed for full P-Power, my guess is it would be a little bigger.