Trimmin Tips for the SV27 Brushless

[Tbone2000]

Hey all,
So I've had my SV27 BL for about a year now and have made some mods to it like adding a second turn fin, extra water pickup, and moving the batteries forward (~1-2 inches) to get the nose down.
My latest additions are 7 cell NiMH packs and 2 grimracer propellers (3 blade hard to get on plane) which make the boat absolutely fly across the water. However, the boat is so fast that at full throttle (or even 3/4) the thing starts bouncing from side to side and hopping across the water. I like the new speed but this thing is totally out of control.
I was just wondering if anyone else has experienced this and what they did to correct it. Maybe moving the batteries out to the sides more would help the side to side roll? I'm lost on what to do about the hopping action.
By the way, what is the fastest SV speed clocked and how was the handling at speed? I think mine is about in the low 40s. I know someone out there must have got this hull into the 50s.

[Ctonez]

I've had mine in the fifties with the Ammo2300.
Keep the batteries central, you want the CG as low as possible. I ran Lipos and never ran 7-cell packs, so I can't really help you too much, but when my boat would chine-walk (waddling from side-to-side) it was usually because the batteries were too far back. Try moving them forward in tiny increments, too far and you'll be nose-steering.
My trim tabs are darn near neutral.

[Tbone2000]

thanks for the info! So how was the handling at that speed? I've seen videos of SVs really haulin across the water and they looked smooth. I hope I can get mine back under control.

[Ctonez]

thanks for the info! So how was the handling at that speed? I've seen videos of SVs really haulin across the water and they looked smooth. I hope I can get mine back under control.

Mine was smooth running by itself, but race water was a big challenge. Taught me alot about driving though, and I won Pmono in our club with it last year, despite running against a fleet of Neu powered Delta Forces . What Grim prop are you using?

[motoxbob11]

My stock setup made 40 mph with Lipos but it was impractical except on the smoothest water. I moved batteries forward but the bigest help for me was adding a bit of trim tab (adjustables from OSE) In my case it really calmed the boat down, at a cost of some speed of course. The boat runs at 35 mph pretty comfortable with CF 45 prop, CG 8.5 inches off the transom, and the trim tabs "2 turns down" from level.

[Tbone2000]

the grimracer props are 40X52/3 and 42/55. The 42x55 seems to be much faster and gets up on plane easier. I had trouble the other day getting the boat to plane with the 3 blade prop. Any other prop suggestions for the stock setup?

I actually ran the boat today in calm water and it handle nicely, still a little bit out of control. I'll look for the trim tabs.

[motoxbob11]

My Grim 42x55 works well but I like the CF 45 better. Actually I thought the stock 3 blade was fine. It ran in the low 30 mph range and everything was very cool. It does cavitate a lot but just hold the throttle wide open and wait...it will jump up soon enough.
Get the trim tabs from OSE. They are well worth the cost.

[Tbone2000]

Yeah, I liked the stock prop too but the thing shredded with my new 7 cell packs. Funny thing is that all three blades were chipped halfway but the boat ran fastest toward the end. Anyway, I didn't realize until I got home that the prop was shot (it was dark out). Fortunately I already ordered the grim props so I could run the next morning.
The 3 blade grim prop worked fine the first day, but yesterday my boat wouldn't get on plane. That's when I put on the 2 blade grim prop and the boat just took off, I mean a real big rooster tail!!!!!! However, I noticed that my packs were pretty hot.
Hey, do those trim tabs bolt right on or do they require drilling?

[ChaKane]

Bolt Straight on. Made to match the current holes.