My cat is not working. Please help!

[domwilson]

The Hydra 120 is a popular choice. I have a couple myself. On the lipos, IMHO That depends on the expected amp draw. 4500 mah or higher with a 20C or higher rating.

[peells]

you will only need an 1800kva with the above mentioned setup and I use an x438 on my mono look at my blog she hauls

[peells]

I was using a 2084kva but it had to many problems I could not open it up all the way so it made to much heat (Feigao) and I am running the 1800kva and still have a bit of trouble getting it all the way to full throttle, my next motor just may be a 1200kva KB 45 I need the extra weight over the rear end to keep it in the water.

[Tony]

I looked at the feigao and KB45 motors on OSE. Its a hard choice to make. Seems like both motors are going to be a good application for this hull.

[G Doggett]

Now that we have figured out what boat you have some good advice has been offered by the guys on this forum.
If it were mine I would go with a Feigao 9XL, Hydra 120,4S lipos ( 4000 - 5000 mah) and start with an X442 prop, which should see about 40 mph.
It's a nice looking cat, how good is the build quality and finish ?
Graham.

[Tony]

Now that we have figured out what boat you have some good advice has been offered by the guys on this forum.
If it were mine I would go with a Feigao 9XL, Hydra 120,4S lipos ( 4000 - 5000 mah) and start with an X442 prop, which should see about 40 mph.
It's a nice looking cat, how good is the build quality and finish ?
Graham.

Good morning! First of all, thanks for all your advices guys.

G Doggett: I think thats a set up i wanted. The hull has four layer all Fibreglass construction with clear coat. Yea, it's nice cat, just the electronic parts that came with it is bad. I guess thats why we all mods our boats. BTW, do i need the Castle Hydra BEC or not?

OSE says 3s w/BEC, and 6s w/o BEC. So, no need on BEC for 4s lipo?

[caretaker]

I think once you go to 4s you need the BEC and you unhook the red wire from the ESC.You can pop the little plastic tag up and pull it out.Don't cut it off like I did because you need it for the Castle link.I actually pulled the tab off that way I don't have to lift it every time I use the link.

[Ub Hauled]

What I do in case I use 4S+ is just buy a 3 dollars short extension and cut the red wire from it and leave the ESC cable intact. Saves you the work of putting it in an puling out every time you switch to more or less cells.

[DISAR]

I had bought exactly the same boat but with different motor. You actually need another motor because yours is 380 and ESC. It is a very light boat, and you can try the Feigao 9 or 10xl or any other brushless 540 xl size with about 1800-2000 kv.
Finally, in mine the propeller broke apart and I placed another one. The point is that the prop. shaft is 4mm therefore you will need a sleeve of 3/16 tube to fit a 3/16 prop. I used the CF 42 mm running on 3s.

[Tony]

I had bought exactly the same boat but with different motor. You actually need another motor because yours is 380 and ESC. It is a very light boat, and you can try the Feigao 9 or 10xl or any other brushless 540 xl size with about 1800-2000 kv.
Finally, in mine the propeller broke apart and I placed another one. The point is that the prop. shaft is 4mm therefore you will need a sleeve of 3/16 tube to fit a 3/16 prop. I used the CF 42 mm running on 3s.

Thanks for the infos. What kind of motor does your boat have?

[DISAR]

It has a China made made motor 2900 Kv, 540 L size (36x60mm). This is not the perfect motor for the boat but runs OK. I am running on Lipos 3s therefore 2900 KV is Ok and prop Graupner 42mm.
The best motor for this boat would be a Feigao XL. Because you do not have many choices with the prop diameter, since it will not fit any larger than 42 mm you can decide what lipos you will use and which motor to buy. So:

a) If you will use 3s lipos go for the Feigao 6XL
b) If you will use 4s lipos go for the Feigao 7 or 8 or 9XL. I believe that the 7XL will give you the best speed.

Of course you can find cheaper motors in e-bay but the Feigao XL will surely give you the best results.

[Tony]

It has a China made made motor 2900 Kv, 540 L size (36x60mm). This is not the perfect motor for the boat but runs OK. I am running on Lipos 3s therefore 2900 KV is Ok and prop Graupner 42mm.
The best motor for this boat would be a Feigao XL. Because you do not have many choices with the prop diameter, since it will not fit any larger than 42 mm you can decide what lipos you will use and which motor to buy. So:

a) If you will use 3s lipos go for the Feigao 6XL
b) If you will use 4s lipos go for the Feigao 7 or 8 or 9XL. I believe that the 7XL will give you the best speed.

Of course you can find cheaper motors in e-bay but the Feigao XL will surely give you the best results.

I was adviced to get a feigao 9XL and run it with 4s Lipo for this hull. Now i'm a little confuse. So, lower number as in 7XL or 6XL is better?

[DISAR]

It is safer to go 4s and 9XL.

[domwilson]

The 6XL and the 7XL are higher kv motors. However they have significantly less torque than the 9 or 10XL's. Those motors are for small riggers and hydros where you want higher kv on less cells with smaller props. Running the 6 or 7XL's in a hull this size can lead to ESC/motor/battery failure as the current draw would be great. Of course you can reduce the draw by using a smaller prop. But on that size hull, IMHO the prop would have to be really small, so it would just cavitate all over the place as the thrust cone would be too small. A good tool to use for general calculations would be to use FE Calc.

[Tony]

The 6XL and the 7XL are higher kv motors. However they have significantly less torque than the 9 or 10XL's. Those motors are for small riggers and hydros where you want higher kv on less cells with smaller props. Running the 6 or 7XL's in a hull this size can lead to ESC/motor/battery failure as the current draw would be great. Of course you can reduce the draw by using a smaller prop. But on that size hull, IMHO the prop would have to be really small, so it would just cavitate all over the place as the thrust cone would be too small. A good tool to use for general calculations would be to use FE Calc.

Thanks for clearing that up. I'll use the feigao 9XL, a 125amp water cooled ESC, and 4s lipo.