VHull needs a bigger BL motor any suggestions??

[ice_spy]

V-hull 870mm x 30.5mm
3/16 cable drive, no liner. K42-K45 prop.
130mm rudder. 80mm drive dog.
Feigao 1516kv 540xl 11 with ceramic bearings. Etti 150A with added cap bank.
Extreme power elite 3S 5000mah 25/40c x2 Y'd for 6S.





I was happy with the performance of the 3 blade however was slighty too much load and almost popped the caps on my esc. ( see video below link )
Dee@ Etti thankfully repaired my esc and i fitted an extra cap bank.

http://www.youtube.com/watch?v=pBCBMGgVu8o

The hull runs very wet on flat water, CG's @approx 30% from transom and stingers @approx +.5deg.
With turn fins @approx 40deg drives the nose in more than having them adjust all the way out @approx 60.
weight is unknown, no GPS on speed, no logging or knowledge on amp draw with this set up. still learning

So im asking for any suggestions to run the same speeds as the 3 blade in the start of the vid without damaging electrics.
Do i need more powerfull motor, more volts, bigger esc...? my lipos are up for replacement too.

[ice_spy]

bump. anybody?

[BHChieftain]

How are the motor temps?

I run a 31" mono with a cc1518 motor (discontinued). I hear the neu1521 are often used in hulls that size. I use a neu 1515 on a 29" hull and it makes plenty of power and runs cool.

I think your kv and lipo setup are good.

Chief

[BHChieftain]

Also, next time you go shopping for lipos think about 35c packs.

Chief

[Mel279]

ice

get the leo 4082 1450kv since you're running on 6s between your boat looks like those typhoon gasser v hull

[Make-a-Wake]

Get your cog back to 28.5% for starters, then I would recommend The 4082 Mel threw out there or a 4074 1400kv range.

[ice_spy]

Thanks,
the mono is a Thai built gasser i think the name of the shop is M-Boat.
temps are good with 2B- K42 to K45. the cog is already closer to 26-28%.
The leopard motors sound really good for the $$$. i will give those recommended kv motors a look
Are the nanotech lipos with high c discharge rate any good?

[Mel279]

I would recomend getting those winmax nano platinum either 40c or 50c, much better than turnigy nanotech

[Make-a-Wake]

Thanks,
the mono is a Thai built gasser i think the name of the shop is M-Boat.
temps are good with 2B- K42 to K45. the cog is already closer to 26-28%.
The leopard motors sound really good for the $$$. i will give those recommended kv motors a look
Are the nanotech lipos with high c discharge rate any good?

Just get the standard Turnigy's or try the Zippy/flightmax, I'm liking them better than Turnigy's now myself.

[lenny]

You need to ditch the deans,
And get 5.5 bullets all the way.
That would be a very good idea to.
Also I would sand the bottom of the hull with #400 sand paper,
That may help it get some air under it and plane better.

[Make-a-Wake]

You need to ditch the deans,
And get 5.5 bullets all the way.
That would be a very good idea to.
Also I would sand the bottom of the hull with #400 sand paper,
That may help it get some air under it and plane better.

Yep, dont sand it smooth, just sort of scuff it up, it allows air bubbles to be trapped under and ride up on a "cushion". Deans are only "rated" up to 60 amps, your new motor will pull thereabouts or more.

[ice_spy]

Great advice thanks. I will replace the deans. The hull being scuffed v's smooth, really? i didnt know that.
So does this only apply to small scale boats or full size race boats also ?
A friend did have a pro Knee board made of ply called the Joker, it had like about 9 concave dimples boared into it like a golf ball effect. It certainly did glide !

[ice_spy]

Looking at the leo 4092 2Y 1390kv. with a special offer from OSE atm offering the water jacket free. would this be suitable ?

Would Etti 150a be insufficent? if so what esc would i need to run the above mentioned BL. I have a spare SK180a?

[Fluid]

Yep, dont sand it smooth, just sort of scuff it up, it allows air bubbles to be trapped under and ride up on a "cushion"...

Sanding the hull bottom smooth is a great idea, use 220 or 320 wet-or-dry paper on a sanding block. Sanding it this way does not let air bubbles form a 'cushion' (a silly idea, don't know where it came from) - a heavy boat won't float on air! What the sanding does is allow the water to stick to the hull surface, water has less friction against itself than it does against a different material. You want the hull bottom to be flat and smooth, but not shiney. This has been proven over and over again on both full-scale and model race boats. It can add a few km/h to your speeds on a well setup boat.

You need a gap between your drive dog and the stinger, too much friction with zero gap and a "thrust bushing". Set the gap to equal the diameter of the flex cable.

One of the reasons you almost blew the ESC is because your wires are far too long. You can easily cut 10 cm out of each ESC wire and still have plenty to reach the packs. All that extra wire just stresses the ESC and is a very common cause of ESC failure. Adding caps is a lot more expensive than shortening the wires.....

Set the model on a flat surface and adjust the stinger to be one to two degrees up at the prop end. That will help to lift the bow and reduce amp draw....while increasing speed. Too much up though and you can expect a blow over. The 42mm prop is pretty small for a hull that size, and the Kv of the motor is high. I'd recommend a motor with a Kv closer to 1300, this will run cooler and with the right prop give very high speeds. High Kv motors are best left to more experienced racers, they are another big reason for so many ESC failures among the less experienced. My 86cm racing mono runs a 1250 Kv motor and wins a lot of races spinning 47 to 50mm props in the mid-80s.




.

[martin]

Fluid is correct on sanding the hull bottom, the roughend surface allows a membrain of water to stick to the hull so that you have water sliding over the water of the lake. Which has less resistance than fibre glass against water,