SV brushless balance point

[rob]

Hi

Firstly, wow does this thing shift....:w00t:...frightening!!

Trouble is, I can't get it to stay on the water..!

3 times out resulting in a flip every time, either during acceleration out of a corner, or full throttle down the straight, and when the pond roughs up with wakes it becomes really twitchy.

Does anyone know the ideal balance point to keep this baby on the water?

Everything is set neutral and batts are shifted slightly forwards to compensate slightly less weight than nimh. Setup I'm running is:

M445 prop
2 x Maxamp 6.0Ah lipos (almost same weight at nimh - and shifted forwards) each lipo having an FMA low voltage cut off module
Transom mounted water pick up

I've ordered OSE adjustable trim tabs and 2nd turn fin (although turning is not an issue).

How can I settle this boat down and actually get some decent run time in?!! :confused1:

Thanks in advance.

Rob
UK

[Rex R]

some have said that the nimhs should be run an inch forward than stock.

[H&MWill]

Trim tabs will help alot. Also an Octura X645 prop seems to settle it down some.

[ice329]

Sounds like to me the M445 is to much for the Lipo's, there light and have more voltage. Try a X642 prop. Make sure your strut is even, use a ruler on the straight edge of the bottom of the boat to check it, a little means a lot. I like mine even but the trim tabs slight positive. seems to work the best, if the strut is positive it gets hairy, the M445 makes it more hairy. The X642 is much calmer. G/L

[Ctonez]

that prop causes my SV's to run way too loose. I prefer the 440/3 for stability/control reasons, without losing much top end.
I also run the batteries so the frontmost part is even with the endbell of the motor.

[whiplash]

Like an air plane, boats turn and pivot on thier balance point. If this point is too far back.......you'll have to give alot of trim tab to get the nose down, thats alot of drag, if its too forward....... every wake you hit, boat will want to pearl :cursing:
I set my point 30-33% of the hull length. same as the chord of an airplane wing.
30 seems to work the best.
sv is 27" long, 30% is about 8" from transome to nose. adjust your batteries till this is balanced on your fingers. lock them down there, dont change'em.
now play with your strut and tabs and props till you get the best ride.
with this set up, Im jumping wakes from behind the livingston dingy rescue boat,
1-2 feet off the water and landing upright everytime. high speed is not a problem. my strut is straight with bottom of boat, my tabs are a hair lower than bottom of boat, and I use a Grim Racer prop, 42X55 balanced, sharpened, and cupped. actul measurement now is
40X55 and sharp.
try that and youll see what I mean. I may not be the fastest boat out there........but I finished the race a few times by myself
:w00t: heheheheheh. I'll take pics of it next pow wow and post it here. G/L ALOHA :thumbup1:

[Ctonez]

I set my point 30-33% of the hull length. same as the chord of an airplane wing.
30 seems to work the best.
sv is 27" long, 30% is about 8" from transome to nose. adjust your batteries till this is balanced on your fingers. lock them down there, dont change'em.


I just went and checked where my balance point is, almost exactly 8"!
since everyone runs differently, with different batteries/props - your explanation is definitely a better way of determining optimum battery placement.:buttrock:

[Avanti]

with my b/p set at 8" the boat was very stable, aired out nicely with the drive strut set at 0 (possibly -.5). But I thought it looked a little slower. there was no chine walk at all and honestly a little boring to drive. I am going to start moving the batteries back in 1/4" incriments to see where it runs the best for me. Every boat and opperator will be different but an 8" b/p is a great start and will settle the boat right down.

my batteries were (6cells) moved fwd by about 2" to get the boat balanced.
I put a sharpie dot on the bottom of the boat and used a small piece of string to sling the boat for balancing.

hope this helps.

[Avanti]

I ran the boat today with the batteries back a quarter inch and it porpoised slightly.

[Bill-SOCAL]

I agree. I started at 8 inches and I am now back just a hair over 0.25". The boat seems a lot more lively now. At 8" it was rock solid, and like you said, a little snoozy to drive.

[Avanti]

at 8" with a 42x55grim two blade the boat will poroise slightly. this prop gets on plane much faster than the three blade.