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Prince 25" Mono

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Prince 25" Mono

Old 04-13-2011, 04:39 PM
  #801  
keithbradley
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Default RE: Prince 25

Hey guys, just thought I would post my setup since it's a little different from the norm.  2200kv outrunner, Scorpion 120 Commander water cooled esc, prather s215 s&b, single 4s 5000mah 46/92C lipo:


Old 06-23-2011, 04:50 AM
  #802  
Basstronics
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Default RE: Prince 25

Got my batteries in. Now to get the boat in the water- hopefully Saturday. Video to come. I got a feeling its going to get real crazy real quick.
Old 07-15-2011, 03:51 PM
  #803  
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Default RE: Prince 25

What is the best place to buy a Prince boat? Who manufactures them? They look like a pretty sweet boat!
Old 07-15-2011, 03:55 PM
  #804  
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Default RE: Prince 25

http://cgi.ebay.ca/carbon-fiber-Boog...item1e5c4f7923

That would be a real nice hull like the Prince
Old 07-16-2011, 04:53 AM
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Default RE: Prince 25


ORIGINAL: TheOtherSide

What is the best place to buy a Prince boat? Who manufactures them? They look like a pretty sweet boat!

Mine is for sale. $100 + shipping.

http://forums.offshoreelectrics.com/...-hull-hardware

Moved up to a big boy, 32" Pursuit.
Old 07-16-2011, 07:34 AM
  #806  
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Default RE: Prince 25

Sweet Boat - Good Deal - It will like mine - Here is my Prince running a huge oval:

http://www.youtube.com/watch?v=g_zNzsPV5bE

Cheers - Steve
Old 11-17-2014, 08:53 AM
  #807  
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Ok, so a bit of a thread resurrection here!

I have madphil's old prince 25, you can see pics of it a few pages back done up in Gulf colours. I have not used it for a while as the motor and bits went into another project and has since sat on the shelf.

I have recently been given a leopard 3660 2700kv and it needs a home, it looks like a nice motor. However it seems to be in a difficult kv range for the 4s that I run this boat on. I have some small props, 36mm to 40mm and with a half decent esc will this motor be ok on 4s in the prince 25, or is it just too much? Batts would be zippy 7.2 5000mah 40-50c in series.

Cheers
Old 11-17-2014, 09:13 AM
  #808  
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Hi intenserapture,

Mathematically 4S x 2700Kv gives you close to 32000 rpm under load, which is high for a monohull, but it can be done.
I would start with a 30 - 32 mm prop, preferably a metal one, sharpened and balanced, to keep your bearings from catastrofic wear.
I'm running an ETTI monohull with a 3700Kv motor on 3S, turning a 32 mm prop, so my loaded rpm is close to yours.

Start small and work your way up, keep a close eye on motortemperature.

Keep us posted.
Old 11-17-2014, 09:23 AM
  #809  
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Hi pombebled,

Thanks for the advice, I do have one 32mm metal prop, sharpened and balanced but when I put it on the boat it looked so small but I will give it ago. The rest are 36mm up, all metal, balanced and sharpened. Well... They were once.

I have a cheapo mystery 100amp esc, is that man enough? I have a swordfish 200amp esc if need be...

I'll chuck it in and keep an eye on temps

Cheers
Old 11-17-2014, 09:42 AM
  #810  
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On my boat, 32 mm looks small too, but 32000 rpm is nothing to sneeze at...

I'm running the 3700Kv motor on an ETTI 90A ESC and it barely gets warm, even on 3S, so a 100A ESC should handle a 4S set-up.

Provided you made the effort to sand the Fets into one plane, to make sure all fets actually touch the watercooler.
If that's not the case, it'll may blow at 20 or 30A Ampdraw.

Here's a picture of one of my 100A Mystery ESC's:



The lighter patches show where the Fets actually had contact with the cooler...

Regards, Jan.
Old 11-17-2014, 10:13 AM
  #811  
intenserapture
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Again, thanks for the advice.

Can you explain more about sanding the fets? Is sanding them ok?

I assume
this is because they are cheap build and not fitting correctly?

Cheers
Old 11-17-2014, 10:18 AM
  #812  
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Originally Posted by pompebled View Post
Hi intenserapture,

Mathematically 4S x 2700Kv gives you close to 32000 rpm under load, which is high for a monohull, but it can be done.
I would start with a 30 - 32 mm prop, preferably a metal one, sharpened and balanced, to keep your bearings from catastrofic wear.
I'm running an ETTI monohull with a 3700Kv motor on 3S, turning a 32 mm prop, so my loaded rpm is close to yours.

Start small and work your way up, keep a close eye on motortemperature.

Keep us posted.
your math is off.... 39,960rpms under load
32,000rpms is actually a good rpm range specially for such a small boat, racing or sport running


Originally Posted by intenserapture View Post
Ok, so a bit of a thread resurrection here!

I have madphil's old prince 25, you can see pics of it a few pages back done up in Gulf colours. I have not used it for a while as the motor and bits went into another project and has since sat on the shelf.

I have recently been given a leopard 3660 2700kv and it needs a home, it looks like a nice motor. However it seems to be in a difficult kv range for the 4s that I run this boat on. I have some small props, 36mm to 40mm and with a half decent esc will this motor be ok on 4s in the prince 25, or is it just too much? Batts would be zippy 7.2 5000mah 40-50c in series.

Cheers
your close to 40k rpms so start with the smallest prop you have and work up checking temps
this little bugger is guna scoot !
Old 11-17-2014, 10:27 AM
  #813  
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Originally Posted by pompebled View Post
On my boat, 32 mm looks small too, but 32000 rpm is nothing to sneeze at...

I'm running the 3700Kv motor on an ETTI 90A ESC and it barely gets warm, even on 3S, so a 100A ESC should handle a 4S set-up.

Provided you made the effort to sand the Fets into one plane, to make sure all fets actually touch the watercooler.
If that's not the case, it'll may blow at 20 or 30A Ampdraw.

Here's a picture of one of my 100A Mystery ESC's:



The lighter patches show where the Fets actually had contact with the cooler...

Regards, Jan.
Jan, a speed control will not blow when you'r only working them at 20 to 30%.... if this happens something else is the problem
I have a Mystery 200A esc and constantly run that one at 55-70amps without water cooling and it never has an issue at all
and it only gets to about 125*f after a long run
Old 11-17-2014, 11:57 AM
  #814  
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Originally Posted by intenserapture View Post
Can you explain more about sanding the fets? Is sanding them ok?
I assume this is because they are cheap build and not fitting correctly?
Cheers
Hi Intense,

I take a piece of flat hardwood, the width of the Fet board and glue a piece of 120 grid sand paper onto it using double sided tape.
I clamp the wood in the vice and move the fets over the sandpaper, this way I have a better control over how much I take off and I can avoid clipping the capacitors.

Once all Fets are in one plane, I use a vacuum cleaner to remove the dust and refit the watercooler.
I usually omit the heatconductive mat (which insulates), but use a smear of heat conductive paste.
Take care not to cause a short on the connectors when you reposition the watercooler by putting a fresh piece of shrinkwrap around the ESC.

@ SRT 10: My math is correct, I always multiply the no load rpm by 0,8 to account for slippage and losses in the drivetrain.

I agree that an ESC will not fail when only working them at 20 to 30%, but that's not what I said; when only a fraction of the Fets have physical contact with the cooler, a small load like 20 -30A may let out the magic smoke.
All the Mystery ESC's I have treated, still work after a decade of running them in competition.

Waterproofing them is a good idea, because they really don't like getting wet when working... (poof).

Regards, Jan.
Old 11-17-2014, 12:09 PM
  #815  
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Originally Posted by pompebled View Post
Hi Intense,

I take a piece of flat hardwood, the width of the Fet board and glue a piece of 120 grid sand paper onto it using double sided tape.
I clamp the wood in the vice and move the fets over the sandpaper, this way I have a better control over how much I take off and I can avoid clipping the capacitors.

Once all Fets are in one plane, I use a vacuum cleaner to remove the dust and refit the watercooler.
I usually omit the heatconductive mat (which insulates), but use a smear of heat conductive paste.
Take care not to cause a short on the connectors when you reposition the watercooler by putting a fresh piece of shrinkwrap around the ESC.

@ SRT 10: My math is correct, I always multiply the no load rpm by 0,8 to account for slippage and losses in the drivetrain.

I agree that an ESC will not fail when only working them at 20 to 30%, but that's not what I said; when only a fraction of the Fets have physical contact with the cooler, a small load like 20 -30A may let out the magic smoke.
All the Mystery ESC's I have treated, still work after a decade of running them in competition.

Waterproofing them is a good idea, because they really don't like getting wet when working... (poof).

Regards, Jan.
so your math???
4cells x 2700kv - 20% does not = 32,000rpms
(no load) = 16.8v x 2700kv = 45,360 rpms - 20% = 36-37,000rpms

most all racers in NAMBA and sport boating etc. calculating rpms as 3.7v per cell x KV = loaded rpms
if you have slippage in your drivetrain you have an issue... flex shafts and piano wire do not loose rpms, again if so you have a mechanical issue

and going back to 20 to 30% amperage through the esc will not smoke it... sanded fets or not
that is such a small amount of current going through the esc vs what it's continuous current rating
Old 11-17-2014, 12:27 PM
  #816  
pompebled
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14,8 x 2700 x 0,8 = 31968 rpm

What I mean is, that if a 100A ESC only has a few Fets in contact with the cooler, it'll burn as soon as the Ampdraw exceeds 20-30A.

Regards, Jan.
Old 11-17-2014, 12:54 PM
  #817  
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Originally Posted by pompebled View Post
Hi Intense,

I take a piece of flat hardwood, the width of the Fet board and glue a piece of 120 grid sand paper onto it using double sided tape.
I clamp the wood in the vice and move the fets over the sandpaper, this way I have a better control over how much I take off and I can avoid clipping the capacitors.

Once all Fets are in one plane, I use a vacuum cleaner to remove the dust and refit the watercooler.
I usually omit the heatconductive mat (which insulates), but use a smear of heat conductive paste.
Take care not to cause a short on the connectors when you reposition the watercooler by putting a fresh piece of shrinkwrap around the ESC.

@ SRT 10: My math is correct, I always multiply the no load rpm by 0,8 to account for slippage and losses in the drivetrain.

I agree that an ESC will not fail when only working them at 20 to 30%, but that's not what I said; when only a fraction of the Fets have physical contact with the cooler, a small load like 20 -30A may let out the magic smoke.
All the Mystery ESC's I have treated, still work after a decade of running them in competition.

Waterproofing them is a good idea, because they really don't like getting wet when working... (poof).

Regards, Jan.
Originally Posted by srt10 View Post
so your math???
4cells x 2700kv - 20% does not = 32,000rpms
(no load) = 16.8v x 2700kv = 45,360 rpms - 20% = 36-37,000rpms

most all racers in NAMBA and sport boating etc. calculating rpms as 3.7v per cell x KV = loaded rpms
if you have slippage in your drivetrain you have an issue... flex shafts and piano wire do not loose rpms, again if so you have a mechanical issue

and going back to 20 to 30% amperage through the esc will not smoke it... sanded fets or not
that is such a small amount of current going through the esc vs what it's continuous current rating
Originally Posted by pompebled View Post
14,8 x 2700 x 0,8 = 31968 rpm

What I mean is, that if a 100A ESC only has a few Fets in contact with the cooler, it'll burn as soon as the Ampdraw exceeds 20-30A.

Regards, Jan.

now you keep changing your math to suit your ideas??
you said no load and that is 16.8V on a 4s pack x 2700kv = 45,360rpms minus your 20%

and just so you know some speed controls do not come with cooling plates at all in the aircraft world, and don't even have airflow over them and they work just fine

and again using a speed control to only 20% of its continuous rating will not blow it up.... sanded fets or no sanded fets touching nothing or something
now if you go above the ratings you will have issues but not at 20% of its designed use


please for the love of God do not post calculations that we as boaters do not use as a baseline figure for setting up FE boats
even the designers of RTR boats use 3.7v per cell x KV to figure out a good reliable system
Old 11-17-2014, 01:26 PM
  #818  
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Wow, I didn't mean to start a debate! I'm not sure what you guys are taking about with all your maths so will do some reading!

32mm prop does not fit so 36mm x 1.4p is as small as I've got. As the motor and esc were free I will give it ago, keep an eye on temps and see what starts to fry first. I will report back...

Thanks for the input, keep it coming as it is much appreciated.

Cheers
Old 11-17-2014, 01:28 PM
  #819  
srt10
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Originally Posted by intenserapture View Post
Wow, I didn't mean to start a debate! I'm not sure what you guys are taking about with all your maths so will do some reading!

32mm prop does not fit so 36mm x 1.4p. As the motor and esc were free I will give it ago, keep an eye on temps and see what starts to fry first. I will report back...

Thanks for the input, keep it coming as it is much appreciated.

Cheers.

no debate really just some simple math the developers use when setting up RTR boats for us to play with

have fun man!!
like you said keep a close eye on temps
run for maybe 30sec and bring it in just to check things out and go from there

srt10
Old 11-17-2014, 01:30 PM
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Trying to do this from a phone, not sure if it will work. But engine is in and this is proposed set up.
Old 11-17-2014, 01:32 PM
  #821  
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36mm prop.

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