cat set up help?

[millzee]

Here's a link to the build so you can see the set up(save me typing it all)
http://forums.offshoreelectrics.com/showthread.php?26294-Mean-Machine-cheapy-nitro-conversion&highlight=

I first tried with a m447 on 4s and it ran around 35mph, 5 minute run and the temps were cold, through it back out for another 5 minutes and got bored, bought it back in and the lipo's still had what I'd guess to be another 5 minutes in them, it'll be great for the kids althought it does take a bit to get it up out of the water from a stand still.
I then through in 2x 6s and kept the m447 on, it got out of the water a lot better and handled ok but I only got 63kph-39mph. After a few runs with the m447 I switched over to a x548 which caused a lot of bounce so I soon changed again up to a x450 which was a big improvement but still a long way from where the goal is, the x450 has awsome pick up, almost top speed from a standing start but the top speed is still only 78kph-48mph, temps are only 40C all around after a 3minute run, and after a few runs with this prop and trying a few different battery placements, I found that with my batteries back at around 28.5-29.5% cog, the boat had a little bit of bounce and couldnt corner at too quicker speed without causing a roll over or flip. With the batteries moved 1/2 inch forward, it ran more settled but it lost a couple mph in top speed:confused2: . I have increased the adjustability of the strut and have the bottom of the strut set to approx: 5-6mm above the bottom of the sponsons and have it set at around zero angle. I'll have some footage once I can get around to cutting out all the boring stuff. Can anyone offer some advise to help me get more speed out of her??:help: Also, I had a lot of glitching with the rx/tx, I'm guessing I'll need to put the antenna outside the hull, this is the first issue I've ever had with the dx3s system, would it just be the carbon cloth in the hatch blocking the receiption?:help:

[kookie_guy]

this should be in the boating Q&A, not the off topic Q&A hehe

[Fluid]

First the radio. If you do not have complete control of your boat, keep it out of the water! The manufacturer gave you a free antenna, use it. Yes, the problem could be the carbon fiber, move the antenna outside where it belongs.

That motor is not suited for 4S, way too low a Kv. On 6S it should be a lot faster with any of the props you tried. Set the CG at 22 cm to start. Place the cat on a flat table and set the strut 3-4mm above the table and angled 1 to 2 degrees up at the prop end. I use a longer strut on my MM, the prop is about 25mm farther back from the transom; yours should still work.

What is the timing on the ESC? It should be at least "normal". If your packs are decent, the x447 should give near 60 mph on 6S2P when the boat is trimmed right. One thing to do is to block sand the sponson bottoms. They are not flat from the factory (no glass boat's sponsons are), and all the paint probably rounded off the edges. Start with 220 grit to get them flat then go to 400.

Let us know how it works. Oh, ask the mods to move the thread to the right place. :wink:



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[millzee]

Thanks fluid, Im greatfull for your response. It sounds like I've got the cog in about the right place so I'll bring the strut down a little an angle it up as you've said. I have the timing at 15, most of the packs are still only new(so I hope they'll liven up a bit with a few cycles) nano 45-90c. I've blueprinted the bottom and have sharp edges so I can rule that one out. I have an antenna tube that'll install b4 I run it next, it was a real pitta not being able to wind it out too far. Thanks again for your advice:thumbup:

P.s. Mods, can you please move this thread to the correct place, sorry!!

[millzee]

this is of the x450 on 6s, the first run is with the cog at around 30-31% and the last couple are at around 29-30%cog

http://www.youtube.com/watch?v=6zeDsZF143I

[Fluid]

The hopping is stealing a lot of your speed. Get rid of it and you'll see higher top end. Another problem is the short time at full throttle, it can take the boat a couple of seconds to reach top speed, but you seldom gave it full throttle long enough.

The hopping can be tough to diagnose, the video does not show the boat in profile much at all so it is hard to see. One thing to try is to raise the strut 2mm at a time until either the prop blows out, or the hop goes away. I never ran a prop that large on mine (45mm max), you have much more blade area so raising the prop may fix the hop. You'll get it right.


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[millzee]

Here's a video trying a x548 and a m447, after putting this video together, I'm wishing I'd tried the x548 longer, I'm now thinking that once I sort this bounce out, it may be a good prop for this set up.

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

[drwayne]

2 weeks and no posts, M8.
Has the missus confiscated your toys ? :smile: