Too big of prop?
12-06-2011, 08:41 PM
#26
RE: Too big of prop?
ORIGINAL: TheFridge189
So if I used this same setup, but with an lower kv lets say aquacraft motor, It wouldn't have these problems at all?
Thanks Shenloco!
Nikko
So if I used this same setup, but with an lower kv lets say aquacraft motor, It wouldn't have these problems at all?
Thanks Shenloco!
Nikko
but if you do try one of the motors from the boats i listed you would need a smaller prop than what those light boats i shown use because if you used the props those boats came with it would make more heat build up because of your large hull that's harder to push through the water.
also with these motors they use in the boats above you will need to run good 2s lipo packs for best performance.
12-06-2011, 08:44 PM
#27
RE: Too big of prop?
Show me some maths dude, "using that motor because thats what everyone else does" is not scientific by any standards, and falls into the "i believe in witchcraft" category by my books.
Vbattery = 14.4V
Cell count: 12
Rinternalpercell = 0.05 ohm
Rinternalbattery = 0.05 ohm * 12 cells = 0.6 ohm
Imotor = 25A
Imotor = Iesc = Ibattery as per Kirchoffs law
Vdropbattery = Ibattery * Rinternalbattery
25A * 0.6 ohm = 15V
Vdrop > Vbattery
Do you see the problem here, which arises from YOU NEGLECTING to take power load constant (voltage drop) into account?
To achieve your fantastic RPM of 57 000 rpm, you will have a voltage drop which is GREATER than the battery voltage!
Thats kind of physically impossible, wouldn't you agree?
Save your witchcraft, I live in the real world. And in this real world, the law of physics applies...
Quod erat demonstrandum
Vbattery = 14.4V
Cell count: 12
Rinternalpercell = 0.05 ohm
Rinternalbattery = 0.05 ohm * 12 cells = 0.6 ohm
Imotor = 25A
Imotor = Iesc = Ibattery as per Kirchoffs law
Vdropbattery = Ibattery * Rinternalbattery
25A * 0.6 ohm = 15V
Vdrop > Vbattery
Do you see the problem here, which arises from YOU NEGLECTING to take power load constant (voltage drop) into account?
To achieve your fantastic RPM of 57 000 rpm, you will have a voltage drop which is GREATER than the battery voltage!
Thats kind of physically impossible, wouldn't you agree?
Save your witchcraft, I live in the real world. And in this real world, the law of physics applies...
Quod erat demonstrandum
12-06-2011, 08:53 PM
#28
RE: Too big of prop?
You know nothing about boat building sorry your 100% incorrect ... Grim racer and pro racers i know on other boat boards desighn the proboat and aquacraft fast brushless boats I THINK THEY KNOW WHAT THEY ARE DOING!!
And you obvously don't!
How can you figure voltage drop of a power source?
if i ran 2 NIMH packs voltage would drop much more when lets say running them in a super V 27 brushless boat than if i ran 2 2s lipo packs and then again i will go further you can buy better quality higher C rated lipo packs and your voltage would drop even less your asumption does not work.... as i state above pro 's desighned these fast brushless boats they know what they are doing...you obvously do not!
And that's why no members who know alot about boats are posting in this thread because it so crazy only knolagable member that i know posted here was Diesel6401
and he summed it up in his post.
I ain't even bothering trying to explain anymore you have a paper and pen when the pros and FE guys have fast brushless boats!
And you obvously don't!
How can you figure voltage drop of a power source?
if i ran 2 NIMH packs voltage would drop much more when lets say running them in a super V 27 brushless boat than if i ran 2 2s lipo packs and then again i will go further you can buy better quality higher C rated lipo packs and your voltage would drop even less your asumption does not work.... as i state above pro 's desighned these fast brushless boats they know what they are doing...you obvously do not!
And that's why no members who know alot about boats are posting in this thread because it so crazy only knolagable member that i know posted here was Diesel6401
and he summed it up in his post.
I ain't even bothering trying to explain anymore you have a paper and pen when the pros and FE guys have fast brushless boats!
ORIGINAL: Von Ohain
Show me some maths dude, ''using that motor because thats what everyone else does'' is not scientific by any standards, and falls into the ''i believe in witchcraft'' category by my books.
Vbattery = 14.4V
Cell count: 12
Rinternalpercell = 0.05 ohm
Rinternalbattery = 0.05 ohm * 12 cells = 0.6 ohm
Imotor = 25A
Imotor = Iesc = Ibattery as per Kirchoffs law
Vdropbattery = Ibattery * Rinternalbattery
25A * 0.6 ohm = 15V
Vdrop > Vbattery
Do you see the problem here, which arises from YOU NEGLECTING to take power load constant (voltage drop) into account?
To achieve your fantastic RPM of 57 000 rpm, you will have a voltage drop which is GREATER than the battery voltage!
Thats kind of physically impossible, wouldn't you agree?
Save your witchcraft, I live in the real world. And in this real world, the law of physics applies...
Quod erat demonstrandum
Show me some maths dude, ''using that motor because thats what everyone else does'' is not scientific by any standards, and falls into the ''i believe in witchcraft'' category by my books.
Vbattery = 14.4V
Cell count: 12
Rinternalpercell = 0.05 ohm
Rinternalbattery = 0.05 ohm * 12 cells = 0.6 ohm
Imotor = 25A
Imotor = Iesc = Ibattery as per Kirchoffs law
Vdropbattery = Ibattery * Rinternalbattery
25A * 0.6 ohm = 15V
Vdrop > Vbattery
Do you see the problem here, which arises from YOU NEGLECTING to take power load constant (voltage drop) into account?
To achieve your fantastic RPM of 57 000 rpm, you will have a voltage drop which is GREATER than the battery voltage!
Thats kind of physically impossible, wouldn't you agree?
Save your witchcraft, I live in the real world. And in this real world, the law of physics applies...
Quod erat demonstrandum
12-06-2011, 08:58 PM
#29
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RE: Too big of prop?
Ok. thank you very much for the information to the both of you guys, truly a huge help!!So, is it really physically impossible to have the traxxas 380 motor run good at all? According to von, the velenion should is good on paper. So I guess the trick is trying to find the right tuning/prop angle and prop size?
Thanks
Thanks
12-06-2011, 09:57 PM
#31
RE: Too big of prop?
Take it easy man, I never claimed that other brands don't know what they do, and I never stated any intention to compete with them either with this setup.
Stop putting words into my mouth please, and discuss like a grown up.
Volkswagen isn't doing wrong in putting inline 4 motors in their cars, just because Ferrari is using V12? Or?
That is kind of the logics you are trying to apply here (using witchcraft).
And you can calculate voltage drop of the battery by using something very simple known as ohms law.
The battery has a internal resistance, and the motor has a max current draw.
multiply the current draw by the internal resistance, and Voila! Voltage drop of the battery!
And its not even witchcraft, its just science
And before you are reactionary attacking my maths, maybe you would care to present any numbers yourself which you believe to be correct?
It's not really constructive of you to discredit my mathematics, without presenting anything better yourself.
Wouldn't you agree?
And I have to this date not seen a single physical theorem where the ownership of a FE boat is relevant to its appliance, and therefore I can only judge your statement about FE ownership as completely irrelevant to this matter.
Stop putting words into my mouth please, and discuss like a grown up.
Volkswagen isn't doing wrong in putting inline 4 motors in their cars, just because Ferrari is using V12? Or?
That is kind of the logics you are trying to apply here (using witchcraft).
And you can calculate voltage drop of the battery by using something very simple known as ohms law.
The battery has a internal resistance, and the motor has a max current draw.
multiply the current draw by the internal resistance, and Voila! Voltage drop of the battery!
And its not even witchcraft, its just science
And before you are reactionary attacking my maths, maybe you would care to present any numbers yourself which you believe to be correct?
It's not really constructive of you to discredit my mathematics, without presenting anything better yourself.
Wouldn't you agree?
And I have to this date not seen a single physical theorem where the ownership of a FE boat is relevant to its appliance, and therefore I can only judge your statement about FE ownership as completely irrelevant to this matter.
12-06-2011, 09:59 PM
#32
RE: Too big of prop?
The Traxxas is NOT good on paper, but its possible to make a boat that moves forward with it.
It will NOT be fast AT ALL.
But if you can't afford any better, then you can't afford any better, and you gotta make the best of what you got.
It will NOT be fast AT ALL.
But if you can't afford any better, then you can't afford any better, and you gotta make the best of what you got.
12-06-2011, 10:22 PM
#34
RE: Too big of prop?
Paralleling will give you less Vdrop over the batteries, but torque will decrease proportionally, and power will decrease by the square root.
On the plus side, you will get longer runtime, and the lifespan of all the components will be significantly longer.
On the plus side, you will get longer runtime, and the lifespan of all the components will be significantly longer.
12-06-2011, 11:08 PM
#35
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RE: Too big of prop?
ORIGINAL: shenlonco
I made lots of brushless boats he needs to run lower voltage and a small prop or it will just cut out like he described all the time due to thermal shut down.
I made lots of brushless boats he needs to run lower voltage and a small prop or it will just cut out like he described all the time due to thermal shut down.
this whole thread is all over the place..
in a 72" hull one needs a big brushless motor
like a Leopard 5692 or the Castle 2028 on 10s min. to wake this hull up without smoking anything
it's always best to up the volts and run lower kvs
12-07-2011, 02:23 AM
#36
RE: Too big of prop?
Thats why maths is so good, because you cant argue with it as long as you are clinically sane.
Which in turn makes me right, since I'm the only one here capable of presenting any sensible calculations at all.
Which in turn makes a couple of other participants here all over the place.
Well observed
Which in turn makes me right, since I'm the only one here capable of presenting any sensible calculations at all.
Which in turn makes a couple of other participants here all over the place.
Well observed
12-07-2011, 06:22 AM
#37
RE: Too big of prop?
ORIGINAL: Von Ohain
Thats why maths is so good, because you cant argue with it as long as you are clinically sane.
Which in turn makes me right, since I'm the only one here capable of presenting any sensible calculations at all.
Which in turn makes a couple of other participants here all over the place.
Well observed
Thats why maths is so good, because you cant argue with it as long as you are clinically sane.
Which in turn makes me right, since I'm the only one here capable of presenting any sensible calculations at all.
Which in turn makes a couple of other participants here all over the place.
Well observed
Do you have eyes both new guy's that posted are saying what i said lower voltage on his 380 will work better and the other member saying a lower KV like i said on higher voltage will work better... what don't you get?
I can tell those 2 guy's messed around with RC boats where you probably did not because what you keep saying just don't work with boats maybe on paper but not out on the water!!
Hate to say it you think you know everything but you don't!!
your the guy who builds a real cars motor putting it all together on paper adding each part together and on paper totaling up HP of things you did and when the motor is compleate your paper HP estamit would be for example 600HP this motor should have with the parts you made it from... but when you get it dynoed it surprisingly only 475HP and you go how can this be... same with what you are doing with your boat on paper tactics it's incorrect only real world testing will make you learn!
good example say i run my super V27 on two 7.2 NIMH packs lets say a cheap venom pack brand the boat will be slow as a dog and have no power BUT if i do the same with 2 NIMH GP or other good brand pack my boat gets faster and has way more power?
How can this be with your paper work they have the same voltage so my motor should go the same RPM ... BUT it don't because the cheaper packs can't power the system!!
and again just because a motor says max amps it draws you can't tell how many RPMs it will be at from voltage drop because every type and also different brand and C rated battery and quality of batttery will drop voltage differently under a motors load so you can know motors RPM for sure with your paper work..
O and i won't bother answering anymore ..like i said go on a real boat message board like i listed above and you will learn from some pro's that post there.
no sense in keeping this going as others said it's out of hand you just think your correct no matter what people say in there posts and even when shown specs from pro built boats you still swear a 4000KV motor is good for 14.4 V in a boat rediculous I am out of here enjoy pointing unknowligable boat guy's in the wrong direction!!
12-07-2011, 06:49 AM
#38
RE: Too big of prop?
As stated before, I never claimed this setup to me a record breaker.
I said i was aiming to make something work from as little means as possible, since this guy got no money for a new setup.
And thats what I did.
It doesn't help if you need a Ferrari, when you got a Skoda and you can barely afford the petrol for it.
And as for the difference in battery pack quality, you tell me how that can be, since your world don't have voltage drop.
My world explains the difference in battery quality with the fact that a better pack has less internal resistance, wich will result in less Vdrop.
And bobs your uncle, science saves the day again, and explains you why there is a difference in performance with two similarly voltage rated pack, but different "quality" (or to be precise, different internal resistance).
Seriously, stop trying to reinvent the wheel man. Men a lot smarter than you and me put together has thought about this before. Maths doesn't lie, and physics isn't wrong.
Just bite into the accepted scientific knowledge, and stop buying into old blacksmiths tales.
And I'm not the guy that build cars.
I'm the guy that build synchronous turbogenerators for Siemens, which we in turn sell to American power companies because noone of their own steam turbos is up to specs.
And unless you have heard of any Babcock & Wilcox nuke power reaktor exploding lately due to clogged steam turbines, you'll know that we did our maths correctly...
By the way, synchronous turbomachines is principally identical to BLDC motors.
So you trust us with your nukes, but hell, keep us away from your FE boat!
I said i was aiming to make something work from as little means as possible, since this guy got no money for a new setup.
And thats what I did.
It doesn't help if you need a Ferrari, when you got a Skoda and you can barely afford the petrol for it.
And as for the difference in battery pack quality, you tell me how that can be, since your world don't have voltage drop.
My world explains the difference in battery quality with the fact that a better pack has less internal resistance, wich will result in less Vdrop.
And bobs your uncle, science saves the day again, and explains you why there is a difference in performance with two similarly voltage rated pack, but different "quality" (or to be precise, different internal resistance).
Seriously, stop trying to reinvent the wheel man. Men a lot smarter than you and me put together has thought about this before. Maths doesn't lie, and physics isn't wrong.
Just bite into the accepted scientific knowledge, and stop buying into old blacksmiths tales.
And I'm not the guy that build cars.
I'm the guy that build synchronous turbogenerators for Siemens, which we in turn sell to American power companies because noone of their own steam turbos is up to specs.
And unless you have heard of any Babcock & Wilcox nuke power reaktor exploding lately due to clogged steam turbines, you'll know that we did our maths correctly...
By the way, synchronous turbomachines is principally identical to BLDC motors.
So you trust us with your nukes, but hell, keep us away from your FE boat!
12-07-2011, 09:38 AM
#40
RE: Too big of prop?
ORIGINAL: TheFridge189
Thank you Von!First of all, I understand that this motor is underpowered. However, I also know from my expeirence in another 28 inch boat, this motor on 14.4v has pushed it to upwards of 35mph. SECOND of all, If you guys are just going to say "You're an idiot go spend upwards of a thousand dollars to get this boat running" I would apreciate it if you left this forum. See what you guys don't understand is how much fun I have had building this boat all myself, and I havnt spent gobs of money on it.. Not to state the obvious, but it's clearly you guys who don't understand the true fun in this hobby, and youare too blinded bymoney to see what this hobby is truly about.Thanks for the little advice you gave me.With bthat nonsense out of the way, I am still not exactly convinced on how lowering the voltage may fix the problem.Could someone explain to me their logic behind this? Ithink the problemis strictly drive train/ pitch issues.Tommorow I willgrease up my flex shaft even more and go from there.
Thanks
Nikko
Thank you Von!First of all, I understand that this motor is underpowered. However, I also know from my expeirence in another 28 inch boat, this motor on 14.4v has pushed it to upwards of 35mph. SECOND of all, If you guys are just going to say "You're an idiot go spend upwards of a thousand dollars to get this boat running" I would apreciate it if you left this forum. See what you guys don't understand is how much fun I have had building this boat all myself, and I havnt spent gobs of money on it.. Not to state the obvious, but it's clearly you guys who don't understand the true fun in this hobby, and youare too blinded bymoney to see what this hobby is truly about.Thanks for the little advice you gave me.With bthat nonsense out of the way, I am still not exactly convinced on how lowering the voltage may fix the problem.Could someone explain to me their logic behind this? Ithink the problemis strictly drive train/ pitch issues.Tommorow I willgrease up my flex shaft even more and go from there.
Thanks
Nikko
12-07-2011, 03:32 PM
#41
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RE: Too big of prop?
Just my 2 cents here but the biggest item everyone is overlooking is power. I am not a boat builder but fly model airplanes glow and electric.
H.P. is everything. The motor is capable of X number of watts - Watts divided by volts = amps. So if the motor is capable of 260 watts then a 14.4 battery / into 260 equals 18.05 amps. Measure the amp draw thru the esc on the load side to verify amps. If motor is overloaded then reduce prop size to get to correct amps. This may require buying several props with different diameters and pitchs.
With airplanes we can reduce amp draw by dropping pitch and keeping diameter gives more thrust. Reducing diameter and keeping pitch gives more speed.
Also make sure to check amp draw with propeller in water loaded condition. Again I do not know boats but even if motor is small with right pitch and diameter the boat will move. It may not be fast but it will move. We do this to slow down airplanes for a more scale speed and action.
Hope this helps. Several watt meters and amp clamps are available. Even Radio Shack has a cheap DC amp meter that justs clamps around the wire. I use a Fluke meter with DC amp Clamp. Also a watts up meter works well also.
Good luck on this motor and boat. Keep going in the hobby. Misery loves company . LOL
H.P. is everything. The motor is capable of X number of watts - Watts divided by volts = amps. So if the motor is capable of 260 watts then a 14.4 battery / into 260 equals 18.05 amps. Measure the amp draw thru the esc on the load side to verify amps. If motor is overloaded then reduce prop size to get to correct amps. This may require buying several props with different diameters and pitchs.
With airplanes we can reduce amp draw by dropping pitch and keeping diameter gives more thrust. Reducing diameter and keeping pitch gives more speed.
Also make sure to check amp draw with propeller in water loaded condition. Again I do not know boats but even if motor is small with right pitch and diameter the boat will move. It may not be fast but it will move. We do this to slow down airplanes for a more scale speed and action.
Hope this helps. Several watt meters and amp clamps are available. Even Radio Shack has a cheap DC amp meter that justs clamps around the wire. I use a Fluke meter with DC amp Clamp. Also a watts up meter works well also.
Good luck on this motor and boat. Keep going in the hobby. Misery loves company . LOL
12-07-2011, 04:15 PM
#42
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RE: Too big of prop?
ORIGINAL: ironman597
Just my 2 cents here but the biggest item everyone is overlooking is power. I am not a boat builder but fly model airplanes glow and electric.
H.P. is everything. The motor is capable of X number of watts - Watts divided by volts = amps. So if the motor is capable of 260 watts then a 14.4 battery / into 260 equals 18.05 amps. Measure the amp draw thru the esc on the load side to verify amps. If motor is overloaded then reduce prop size to get to correct amps. This may require buying several props with different diameters and pitchs.
With airplanes we can reduce amp draw by dropping pitch and keeping diameter gives more thrust. Reducing diameter and keeping pitch gives more speed.
Also make sure to check amp draw with propeller in water loaded condition. Again I do not know boats but even if motor is small with right pitch and diameter the boat will move. It may not be fast but it will move. We do this to slow down airplanes for a more scale speed and action.
Hope this helps. Several watt meters and amp clamps are available. Even Radio Shack has a cheap DC amp meter that justs clamps around the wire. I use a Fluke meter with DC amp Clamp. Also a watts up meter works well also.
Good luck on this motor and boat. Keep going in the hobby. Misery loves company . LOL
Just my 2 cents here but the biggest item everyone is overlooking is power. I am not a boat builder but fly model airplanes glow and electric.
H.P. is everything. The motor is capable of X number of watts - Watts divided by volts = amps. So if the motor is capable of 260 watts then a 14.4 battery / into 260 equals 18.05 amps. Measure the amp draw thru the esc on the load side to verify amps. If motor is overloaded then reduce prop size to get to correct amps. This may require buying several props with different diameters and pitchs.
With airplanes we can reduce amp draw by dropping pitch and keeping diameter gives more thrust. Reducing diameter and keeping pitch gives more speed.
Also make sure to check amp draw with propeller in water loaded condition. Again I do not know boats but even if motor is small with right pitch and diameter the boat will move. It may not be fast but it will move. We do this to slow down airplanes for a more scale speed and action.
Hope this helps. Several watt meters and amp clamps are available. Even Radio Shack has a cheap DC amp meter that justs clamps around the wire. I use a Fluke meter with DC amp Clamp. Also a watts up meter works well also.
Good luck on this motor and boat. Keep going in the hobby. Misery loves company . LOL
like about 4,000 cont. thats about 108-110amps cont. on 10S (37V)
and possibly 200amps+ peak
12-07-2011, 06:02 PM
#43
RE: Too big of prop?
Guys, Its easy to see that this motor is underpowered here and nobody is denying the fact that the motor is to small.
Nobody has overlooked that he needs more watts.
But I believe some of you are overlooking what the poor guy is actually saying.
He has no money for a new setup!
If he needs a bigger setup just doesn't help it if he cannot afford it.
Shalll we help him make the most of the means he got, or shall we tell him all the VERY expensive gear he needs to make a BIG FE boat, which he cannot afford anyway?
As long as he can't afford it, I'll say you are just making the hobby more hopeless for him.
He needs a more powerful motor, he knows that by now. But he still cannot afford it.
So what do we do? Sell him a pipe dream, or help him do something with what he actually got?
Justaddwata:
I'm sorry that a good topic came to this discussion, but I do believe that letting people know who is right is useful when there is bogus information on the loose.
That is because Electric drivetrain for R/C is complicated enough for an experienced modeller, let alone hopeless for a beginner.
And having seemingly experienced forum members very pedantically enforce bogus mathematics is certainly not making the topic of electric drivetrains
any less complicated for the layman trying to understand it.
I therefore saw the need to defend my statements using what you perscieve as juvenile arguments.
As long as my arguments is backed by facts and science, I don't really agree that its juvenile bickering on my part, but lets agree to disagree on that.
Anyway, to draw some sensible experience out of this, I see that there is a lot of confusion revolving around electric drivetrains, even from the experienced modellers.
So that does to me clarify that there is a need for a sticky to explain this matter in more detail.
I am aware such a guide does exist aready, but maybe its not visible enough, and maybe its not detailed enough, since obviously many is still confused?
Anyway, if you agree with me on this point, I would be happy to contribute with some scientific facts. Backed up by sources in university level schoolbooks, with references, if desired.
Nobody has overlooked that he needs more watts.
But I believe some of you are overlooking what the poor guy is actually saying.
He has no money for a new setup!
If he needs a bigger setup just doesn't help it if he cannot afford it.
Shalll we help him make the most of the means he got, or shall we tell him all the VERY expensive gear he needs to make a BIG FE boat, which he cannot afford anyway?
As long as he can't afford it, I'll say you are just making the hobby more hopeless for him.
He needs a more powerful motor, he knows that by now. But he still cannot afford it.
So what do we do? Sell him a pipe dream, or help him do something with what he actually got?
Justaddwata:
I'm sorry that a good topic came to this discussion, but I do believe that letting people know who is right is useful when there is bogus information on the loose.
That is because Electric drivetrain for R/C is complicated enough for an experienced modeller, let alone hopeless for a beginner.
And having seemingly experienced forum members very pedantically enforce bogus mathematics is certainly not making the topic of electric drivetrains
any less complicated for the layman trying to understand it.
I therefore saw the need to defend my statements using what you perscieve as juvenile arguments.
As long as my arguments is backed by facts and science, I don't really agree that its juvenile bickering on my part, but lets agree to disagree on that.
Anyway, to draw some sensible experience out of this, I see that there is a lot of confusion revolving around electric drivetrains, even from the experienced modellers.
So that does to me clarify that there is a need for a sticky to explain this matter in more detail.
I am aware such a guide does exist aready, but maybe its not visible enough, and maybe its not detailed enough, since obviously many is still confused?
Anyway, if you agree with me on this point, I would be happy to contribute with some scientific facts. Backed up by sources in university level schoolbooks, with references, if desired.
12-07-2011, 06:08 PM
#44
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RE: Too big of prop?
no one is selling the OP a pipe dream...
many people on these forums who have a lot of knowledge when it comes to big FE
when the OP gets the money he will be headed into the right direction knowing more watts is what is needed and lots of volts for a hull of this size
he is going to do just fine, once he gets the cash
many people on these forums who have a lot of knowledge when it comes to big FE
when the OP gets the money he will be headed into the right direction knowing more watts is what is needed and lots of volts for a hull of this size
he is going to do just fine, once he gets the cash
12-07-2011, 08:56 PM
#45
RE: Too big of prop?
ORIGINAL: Von Ohain
Justaddwata:
I'm sorry that a good topic came to this discussion, but I do believe that letting people know who is right is useful when there is bogus information on the loose.
That is because Electric drivetrain for R/C is complicated enough for an experienced modeller, let alone hopeless for a beginner.
And having seemingly experienced forum members very pedantically enforce bogus mathematics is certainly not making the topic of electric drivetrains
any less complicated for the layman trying to understand it.
I therefore saw the need to defend my statements using what you perscieve as juvenile arguments.
As long as my arguments is backed by facts and science, I don't really agree that its juvenile bickering on my part, but lets agree to disagree on that.
Anyway, to draw some sensible experience out of this, I see that there is a lot of confusion revolving around electric drivetrains, even from the experienced modellers.
So that does to me clarify that there is a need for a sticky to explain this matter in more detail.
I am aware such a guide does exist aready, but maybe its not visible enough, and maybe its not detailed enough, since obviously many is still confused?
Anyway, if you agree with me on this point, I would be happy to contribute with some scientific facts. Backed up by sources in university level schoolbooks, with references, if desired.
Justaddwata:
I'm sorry that a good topic came to this discussion, but I do believe that letting people know who is right is useful when there is bogus information on the loose.
That is because Electric drivetrain for R/C is complicated enough for an experienced modeller, let alone hopeless for a beginner.
And having seemingly experienced forum members very pedantically enforce bogus mathematics is certainly not making the topic of electric drivetrains
any less complicated for the layman trying to understand it.
I therefore saw the need to defend my statements using what you perscieve as juvenile arguments.
As long as my arguments is backed by facts and science, I don't really agree that its juvenile bickering on my part, but lets agree to disagree on that.
Anyway, to draw some sensible experience out of this, I see that there is a lot of confusion revolving around electric drivetrains, even from the experienced modellers.
So that does to me clarify that there is a need for a sticky to explain this matter in more detail.
I am aware such a guide does exist aready, but maybe its not visible enough, and maybe its not detailed enough, since obviously many is still confused?
Anyway, if you agree with me on this point, I would be happy to contribute with some scientific facts. Backed up by sources in university level schoolbooks, with references, if desired.
I welcome the inputs and insights of anyone - right and sometimes wrong. I think it will be evident to the OP who makes the best point and who does not. But remaining civil and on topic will go a long way to making this forum a home for the pleasant exchange of ideas and the continued growth of the hobby.
There has to be room for more than one opinion (right or wrong) in a thread. Play nice with your fellow boaters - this is supposed to be fun
12-07-2011, 08:59 PM
#46
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RE: Too big of prop?
If you are looking for a budget build, you can probably get a big brushed motor from a blender or some other kitchen appliance. Some blenders have monstrous motors inside.
These would be good because they have a hell of a lot of torque. Problem here is that they run on 120 volts.
No problem, if you can get some copper wiring you can easily rewind a brushed motor for more rpms and you will have yourself a more powerful motor, all be it less efficient.
You can probably find some old kitchen appliances in a dump or something. not too sure.
But it would probably be easier to go with a massive brushed motor instead of brushless.
The controllers are also a lot less expensive.
Heck, you could also get those super strong neodymium magnets and stick those to the sides of your brushed motor, it's a real quick fix to get more power from brushed motors.
Also with a brushed setup you would need a big prop because you aren't getting the same rpms, but with enough torque you could swing a mighty big prop.
Hope this is helpful.
Clock.
These would be good because they have a hell of a lot of torque. Problem here is that they run on 120 volts.
No problem, if you can get some copper wiring you can easily rewind a brushed motor for more rpms and you will have yourself a more powerful motor, all be it less efficient.
You can probably find some old kitchen appliances in a dump or something. not too sure.
But it would probably be easier to go with a massive brushed motor instead of brushless.
The controllers are also a lot less expensive.
Heck, you could also get those super strong neodymium magnets and stick those to the sides of your brushed motor, it's a real quick fix to get more power from brushed motors.
Also with a brushed setup you would need a big prop because you aren't getting the same rpms, but with enough torque you could swing a mighty big prop.
Hope this is helpful.
Clock.
12-07-2011, 09:07 PM
#47
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RE: Too big of prop?
ORIGINAL: clockworkclock
If you are looking for a budget build, you can probably get a big brushed motor from a blender or some other kitchen appliance. Some blenders have monstrous motors inside.
These would be good because they have a hell of a lot of torque. Problem here is that they run on 120 volts.
No problem, if you can get some copper wiring you can easily rewind a brushed motor for more rpms and you will have yourself a more powerful motor, all be it less efficient.
You can probably find some old kitchen appliances in a dump or something. not too sure.
But it would probably be easier to go with a massive brushed motor instead of brushless.
The controllers are also a lot less expensive.
Heck, you could also get those super strong neodymium magnets and stick those to the sides of your brushed motor, it's a real quick fix to get more power from brushed motors.
Also with a brushed setup you would need a big prop because you aren't getting the same rpms, but with enough torque you could swing a mighty big prop.
Hope this is helpful.
Clock.
If you are looking for a budget build, you can probably get a big brushed motor from a blender or some other kitchen appliance. Some blenders have monstrous motors inside.
These would be good because they have a hell of a lot of torque. Problem here is that they run on 120 volts.
No problem, if you can get some copper wiring you can easily rewind a brushed motor for more rpms and you will have yourself a more powerful motor, all be it less efficient.
You can probably find some old kitchen appliances in a dump or something. not too sure.
But it would probably be easier to go with a massive brushed motor instead of brushless.
The controllers are also a lot less expensive.
Heck, you could also get those super strong neodymium magnets and stick those to the sides of your brushed motor, it's a real quick fix to get more power from brushed motors.
Also with a brushed setup you would need a big prop because you aren't getting the same rpms, but with enough torque you could swing a mighty big prop.
Hope this is helpful.
Clock.
you would need one heck of a brushed esc to handle the amps and volts, and that actually could get expensive
but it would be killer to find a brushed motor to handle it if it was cheaper
12-07-2011, 09:26 PM
#48
RE: Too big of prop?
My opinion is as subjective as everybody elses.
Maths is undisputable truth.
I can still not by my best goodwill see how its juvenile of me to back up my claims with maths and physics.
In fact, in my opinion it is juvenile to do the opposite.
To throw statements around without being able to back them up!
But I can agree to disagree on it.
And I do really believe it is important to be clear on what is right and wrong, since a lot of modellers does seek forums like this for advice, and could potentially waste a lot of money buying wrong.
But its not my forum so I don't make the rules. But do please at least consider what I'm saying, I am one of a few persons in here with a professional background from electrics and electronics.
I believe it would be unwise to not consider advise from a professional.
Maths is undisputable truth.
I can still not by my best goodwill see how its juvenile of me to back up my claims with maths and physics.
In fact, in my opinion it is juvenile to do the opposite.
To throw statements around without being able to back them up!
But I can agree to disagree on it.
And I do really believe it is important to be clear on what is right and wrong, since a lot of modellers does seek forums like this for advice, and could potentially waste a lot of money buying wrong.
But its not my forum so I don't make the rules. But do please at least consider what I'm saying, I am one of a few persons in here with a professional background from electrics and electronics.
I believe it would be unwise to not consider advise from a professional.
12-07-2011, 09:56 PM
#49
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RE: Too big of prop?
Okay guys so I have sort of givin up on this 380 vxl trying to work. I have the perfect setup in mind to make this boat actually move fast, don't worry. But all I can say is it will more then likely be the fastest big scale rc boat you will ever see. Anywho, the reason I asked this question in the first place was to see if it was possible to get my vxl motor to run efficently in my boat. However, from your guys really helpful insight, I have come to an consensus that this motor will fail to work in this boat. The truth is, I have the money, its just I wanted to try to be a miminalist on this build, as well as I just wanted to get on the water witth what I have, however it proved to be a headache. Oh well, no money came out of my pocket though. I thought this would be easily possible,because of my experiences with this setup in smaller boats. i just find it so odd that when I have the motor and esc set up in the big boat with literally EVERYTHING the exact same as in my other hull, it refuses to work. the esc really doesnt like to work. Maybe it just has a personal gripe with my hull.
Thanks
Nikko
Thanks
Nikko
12-07-2011, 10:43 PM
#50
RE: Too big of prop?
ORIGINAL: Von Ohain
My opinion is as subjective as everybody elses.
Maths is undisputable truth.
I can still not by my best goodwill see how its juvenile of me to back up my claims with maths and physics.
In fact, in my opinion it is juvenile to do the opposite.
To throw statements around without being able to back them up!
But I can agree to disagree on it.
And I do really believe it is important to be clear on what is right and wrong, since a lot of modellers does seek forums like this for advice, and could potentially waste a lot of money buying wrong.
But its not my forum so I don't make the rules. But do please at least consider what I'm saying, I am one of a few persons in here with a professional background from electrics and electronics.
I believe it would be unwise to not consider advise from a professional.
My opinion is as subjective as everybody elses.
Maths is undisputable truth.
I can still not by my best goodwill see how its juvenile of me to back up my claims with maths and physics.
In fact, in my opinion it is juvenile to do the opposite.
To throw statements around without being able to back them up!
But I can agree to disagree on it.
And I do really believe it is important to be clear on what is right and wrong, since a lot of modellers does seek forums like this for advice, and could potentially waste a lot of money buying wrong.
But its not my forum so I don't make the rules. But do please at least consider what I'm saying, I am one of a few persons in here with a professional background from electrics and electronics.
I believe it would be unwise to not consider advise from a professional.
Sure it is wise to consider the advise from a professional. I am sure it is appreciated. But do not feel it your responsibility to overpower any other opinion or suggestion out there too. Share your opinion/perspective - but be open to what others have to say - who knows - you just may learn something (and I am sure even the best among us has room to learn a little more)
