***Calling all GURUS Help Needed on SET-UP figures***

[exotica]

Okay, as some of you might have read in a few of my recent posts, im very new to Rc boating. I have recently purchased a 29" Cat hull which is fitted out with a Nemesis 9XL motor, Hydra 120, 2x 2S 7.4v 5000mah lipos and an Octura X445 prop.

Can some of the experts in here please help me in some figures related to current draw, amp draw, motor rpm etc. I can seem to find the technical specs on the motor to enable me to do some calculations of my own. I want to ensure that everything is right as I have smoked a Hydra 120 on the bench! They are replaceing it but want to ensure that my set up is right and im not asking to much from the ESC, I believe im not hower im no expert nor do i have a great deal of experience in RC Boating coming from an RC Car background.

Thanks in advnance for any information or guidance.

cheers

Kosta.

[domwilson]

The CC's ESC's have had a few problems lately. I would go to a smaller prop like a X440 or X442. But I don't think that is the reason you blew your ESC. How long did you run it on the bench? It's not good to run a brushless motor for any extended time without a load on it. Does your drive line spin freely? Have you lubed the shaft? There are alot of variables here.

[exotica]

...was on the bench for no more than 20 seconds at 1/4 throttle. Noticed the smoke developing and stopped. I dont think the props the issue here either as it appears the ESC is arcing internally, which leads me to believe its faulty. I showed a friend of mine and he tends to agree. There was only one battery connected at the time.

The shaft is well greased and the driveline is as smooth as silk.

[Bigmaxy]

Hi. Not saying it was the cause of your problem but brushless esc's perform best at full throttle. Running at 1/4 throttle is very hard on them and will cause them to heat up far quicker than running flat out.
Sorry this doesn't answer you initial question.

Goes without saying that the 2S Lipos are being run in series I assume otherwise you would have one slow a$$ boat. I have run similiar setups and tend to run around x640 x440/3.

The Eagle Tree has shown bursts of up around 80A but more like around 50A. I tend to just go by how how things are getting these days.

If you have access to some smaller props it might be wise to start a bit smaller than what you are running.

At lot depends on how wet you are running and whether you are prepared to run a racers setup that puts everything on the edge of heat/life expectancy.

Good luck. (ps. Hope the real gurus reply to you, I am most certainly not. lol )

[exotica]

...I will be running wetter (meaning you have more hull in the water at wot?) than usual and not have the set up running on edge. I want a relatively quick boat for some fun on the ponds.

I also hope a few more with experince do chime in with some more info. I understand that the ESC will heat up at 1/4 or 1/2 throttle but they should not smoke on a test bench when run for between 10-30 secs. I am using the X445/2 prop which is the right one im led to believe with hte smaller x442/2 i have yet to try. I want to set the boat up properly so it runs perfectly with the 445 and enables me to use the 442 for a little extra run time.

Im still trying to chase down some actual specs on this motor as the FDM website only lists kv/rpm.

[ozzie-crawl]

what hull are you running ?

[exotica]

....hi Oz, hull is a 29" Skunk Cat.

[Gary]

[QUOTE=exotica;139190]...was on the bench for no more than 20 seconds at 1/4 throttle. Noticed the smoke developing and stopped. I dont think the props the issue here either as it appears the ESC is arcing internally, which leads me to believe its faulty. I showed a friend of mine and he tends to agree. There was only one battery connected at the time


My brand new 240 hydra replacement smoked on program mode on the bench!!! Very disapointing .

[DISAR]

exotica

Your setup should draw around 80-100 amps. Start with a 442 first and check temperatures. Your prop must spin by hand easily, bottom of strut 5 mm above bottom of sponsons and parallel or 1-2 degrees up. Propellers must be balanced and sharpened, or try the Graupner 2317.42, 3217.45 which do not need any preparation
http://www.offshoreelectrics.com/products.php?cat=58

[domwilson]

...I will be running wetter (meaning you have more hull in the water at wot?) than usual and not have the set up running on edge. I want a relatively quick boat for some fun on the ponds.

I also hope a few more with experince do chime in with some more info. I understand that the ESC will heat up at 1/4 or 1/2 throttle but they should not smoke on a test bench when run for between 10-30 secs. I am using the X445/2 prop which is the right one im led to believe with hte smaller x442/2 i have yet to try. I want to set the boat up properly so it runs perfectly with the 445 and enables me to use the 442 for a little extra run time.

Im still trying to chase down some actual specs on this motor as the FDM website only lists kv/rpm.

You don't want it to run wetter unless you are having handling issues. You want less hull n the water (up to a point) to reduce the load on your drive system which in turn will reduce amp draw. Maybe Jay Turner (Fluid) will chime in. He is very knowledgeable about cats. But all this is irrelevant as you blew your ESC on the bench. I tend to think it was an ESC issue. But I myself have not run a motor unloaded for more than a few seconds as heat builds up rather quickly. Once you get your new ESC, make the recommended adjustments to your strut, start out with a smaller prop, and do your testing on the water. It never hurts to have an extra, comparable, ESC as a backup.

[exotica]

...thanks Dom, Fluid has sent me a pm with some very helpfull info. I will now use the X442 instead of the X445 to start with not believing that the prop was the issue why the ESC smoked. I have adjusted the strut down so it is now level with the bottom of the sponsons. Now that this adjustment has been made im hopefull that it stops the nose from wanting to lift up and blow over. I have also moved the lipos further forward a little to get a little more weight up front.

....Disar, that Graupner prop you suggested is similar to the 442. I have ordered a X440 also which is almost identical to the 2317.40.

[domwilson]

Let us know what you finally end up with and the results. I'd like to see pics and video of your finalized setup. Thanks.

[exotica]

...a few months on and i think im going to get this thing wet again. Everything is set up ready to go with the new himodel esc. The new 120amp hydra has been shelved for now and will run with the himodel after ensuring its programmed properly with no brake active. I have also made the adjustements to the drive shaft which im hopefull will stop the front from lifting up and rolling over as occured on my first run.

[Raydee]

Are you or were you using the internal BEC? The CC controllers are only good for 3s using the internal BEC. At 4s you will need a receiver battery or external BEC.

[Heath M]

Lets us know how you go Kosta, I found with mine about 2mm or the thickness of 2 credit cards under the nose of the strut to create down angle worked well for the handling.

Heath