Hi Guys,
This is my first post here. I have a Kyosho RC Surfer that I drowned in salt water a few years ago and destroyed the electronics in it. Now I want to rebuild it better, faster, stronger.
So I bought a Mtroniks Genesis 40 brushless ESC from ebay and ordered a Feigao 540 12S (kv=2958 rpm/V) brushless motor from offshoreelectrics.com. The motor draws 54A max but I think the 40A controller will be enough since I will only be running it on 6cell packs. Am I wrong on this?
The stock prop is an Octura X431. An online speed calculator tells me it will go 21 mph (25% slip). Is this realistic? Someplace else I found that a stock surfer goes 9mph (it seemed faster than that but ok).
My goals are long run time, better performance but not too extreme, and low maintenance. Am I on the right track?

It seems nobody has any advice or comments. That's ok, I'll try it out the way I planned and report back with the results, maybe it will help someone else. I received the brushless motor and coupler today (offshoreelectrics.com has incredibly fast shipping!) but the ESC has not arrived yet. The brushless went in without too many problems so the hard part is done. The brushless motor is noticeably heavier than the old 550 motor, hopefully it will make up for it in power and efficiency.

What should I lube my drive shaft with? It is a solid 4mm stainless shaft in a brass stuffing tube. I tried axle grease but it was way too viscous (too much drag). Then I tried gun oil but that seems too light.

well ok 21 mph seems a good speed for that set up and with 6 cells yes 25mph isnt out of the question
ok well just get some lithuim grease from a marina (just ask if they sell lithium grease) and that will be god for the lube . i also see you have a plastic prop , GET rid of that if you get a good brass one or carbon one you will get better preformance and speed

also if you dont have one already buy some 3300mah batteries for it you will get a lot longer runtime
have fun with the boat it will prefom welll for you, but if it doent go to a smaller prop
your run time will vary with a 3300mah pack you should get about 15 mins out of it , and rember it is all in how you drive it

oh and by the way fix the water cooling get a better water pick up from under the hull, and put more tubing around the motor to keep it cool, rember the cooler it is the longer it will last

Alex,
Got to WalMart, ask for fishing reel grease. Works fine lasts a long time. Nothing wrong with lithium but you just don't need a gallon of the stuff, right? I'd also think about swapping the prop for one with a bit finer pitch, or slightly smaller diameter (cavitation). Give it a try first, though! May not need to worry about it. Brushless motors are high current draw thingys. Don't expect hours of run time. And since your ESC isn't quite heavy enough for the max current, you might take it a bit easy, keep your foot off the gas and check for heat fairly often. Too much is always better than not enough, just not as 'frugal' in the long run...
Good luck.
- 'Doc

Hey thanks for the fishing reel grease tip, I will get some of that.
So what is wrong with the water pickup? Should it extend deeper into the water? I made it short so it wouldn't cause too much drag. Should the tube have a bend in it so water is pushed in more forcefully? The kit instructions said to simply cut it at an angle like I've done. I have never been able to see cooling water shoot out through the exit tube while running, maybe the bad pickup design is why, I just thought it was too hard to see at speed. Wouldn't a bigger pickup also slow the boat down?
Here is a closeup of the pickup it currently has.
Good batteries are next on my list. The 4200mah cells are looking tempting, as are the 3800's. Why do you recommend the 3300's? I am building a brushless RC10T4 also which will use the same bettery packs.
-Alex

Actually your cooling inlet may be a bit long. Cut it so it's flush with the bottom of the hull, so that the bottom of your hull is smooth with nothing protruding from it. You want your cooling tube so it's going into the hole in your hull's bottom at an angle toward the front of the hull. You can even put a bend in it so it's pointed towards your motor.

I don't know if that makes sense or not to anyone but me, but if not here's a diagram of what I'm trying to say!

Hope this helps.

The ESC arrived and the boat is ready for the lake. Wal-Mart did not carry fishing reel grease for the prop shaft so I'm using generic vaseline for now. I did get some weatherstripping tape at Wal-Mart that holds my battery in place. The batteries used to slide into the motor coupler and get chewed up. Now with four pieces of foam tape on the bottom and one piece on the boat lid, the battery is gently "sandwiched" and held in place by the grippy foam. Another plus is there is a small air space around the battery for better cooling.

The Mtroniks Genesis 40 ESC is a terrible choice for a boat and I am going to replace it with a better model. This is why:
1. There is a one second delay every time you let off the throttle. If you do not wait one second before applying throttle again, it won't go. Some kind of "safety" delay. Totally unacceptable.
2. The ESC expected more throttle travel than my radio could provide. It would only work if I used the entire forward and reverse throw for forward throttle. I have a rubber band on my throttle trigger which holds it into the max reverse position.
3. No reverse (I expected this since it is a flight ESC)
4. Does not claim to be waterproof even though it is entirely potted. The instructions say to keep it away from water. I suspect it is highly water resistant though.
5. It is very big and heavy. Maybe twice as much as a typical car ESC. That makes it useless as a flight ESC so it is pretty much useless in any application. No wonder why it was only $45 on ebay.

Does anyone have any better ESC suggestions? The ones at offshoreelectrics.com look nice but so much $$$.

The good part is I can still run the boat and see what she's capable of under brushless power. I'll be using my lunch break to go to the local lake for the maiden voyage. Preliminary tests in my hot tub show lots of thrust, maybe 50% more than what I remember.

The new brushless setup works great! The water cooling doesn't seem to be working at all (I can't see any water coming out of the exit hole) but it doesn't need it... the motor was just barely warm after running. The top speed was limited by the fact that the boat jumps out of the water and rythmically bobs up and down, the prop coming out of the water each time. This made it a lot of fun to drive as you could get it to do 180's in the air if you timed it right. It was a lot of fun and will be a good toy for the summer. If I get a chance this weekend I'll put up some video.

tha is called propousing to fix it change the angle of the prop exiting the hull or get trim tabs
but cuz its a surf board it would be cool to see
so i say leave it

Hey Alex- Your set up looks pretty good. Here's a couple of ideas.


Looks like you have solved this already but- To hold the battery pack in place you can use some velcro patches. Place one near the edge closest to the motor and then attach some pieces to all your battery packs. I use the fuzzy side of the velcro on the battery packs and grabby part (technical term) in the board itself. The velcro not only holds the batttery pack but it also elevates it slightly above your u joint or motor coupler.

You can also fit 7 cells in there though you may have to cut away a little of the shrink wrap in the front of the battery pack to give clearance for your cen racing u joint. The 7th cell would be attached to your six cell pac cross ways at the end nearest the rear of the hull. This will also help balance the board so it doesn't bounce around as much.

Someone suggested making a bigger coil to keep the motor cooler and I totally agree. If you decide to add a water cooled speed controller you can add another water pick up made from brass to the other side of the hull. Make the exhaust hole on the right side of the hull. Basically opposite of the one that's there now. Your intake looked fine in the picture you posted. I would check and make sure it isn't plugged with anything. You should be able to blow air through it fairly easily. Another test is, get a mouth full of water and blow the water through the exhaust hole on the side. If your making a new one you can use bigger diameter brass tubing then the stock set up. Yes it will help if you angle the intake slightly forward. You can exit an 1/8 inch from the bottom of the hull without incurring any noticeable drag.

I saw your movie (nice music btw) and it looks like you getting some good speed. If you want to bump it up another notch you can try the Mega Motor 22/20/2 with a 70amp Hacker navy controller. This set up rocks on 7 cells.

I use marine grade grease in the stuffing box.

Here's a shamless plug......A friend and I actually produced a movie/DVD about RC Surfing called Radio Waves. It includes a bunch of modifications you can make as well as some pretty cool rc surfing footage. There's a review in the latest issue of Radio Controlled Boat Modeler (2006 Buyers guide) as well as the March issue of Surfer Magazine. There is also a teaser clip on my website just in case your interested in seeing what is possible with a modified rc surfer.

reeseproductions.com

Dave

Thanks for the tips Dave. I saw your sample footage once before... that is incredible. I have surfed mine in ocean waves before and it's not easy at all. The driver in your movie is very talented! Santa Cruz is an ideal place to play with the RC surfer, but do the real surfers get annoyed?
I water cooled the ESC and actually removed a coil from the motor since it just doesn't get hot. It was the ESC that was thermaling, the water cooling solved that. I really like the run time I get with this setup, but a 7 cell battery would be good to have as a "speed battery".
-Alex

Your welcome Alex.

Yeah, Spencer has the RC Dude totally dialed. That's the guy controlling the rc surfer in the movie as well as most of the footage in that teaser clip.

Most of the surfers get along with rc really well. Even some of the pro surfers like Adam Replogle and Jason 'Ratboy' Collins have given him the green light to take waves. Both those surfer are in the movie btw. It comes down to showing respect and staying out of the way. The cool thing with rc is you can sit off to the side of the main peak and jam in if no one else is going for it. It's easy to loose sight of the dude when a set comes in so it's very important to always be aware of where rc is in relation to the real surfers. Once you get some experience and learn the particular spot your surfing you shouldn't have too many problems. Without a doubt it's safer to start at a beach with no surfers or swimmers if you can. Occasionally you get a guy that feels threatened by rc, but hey those guys are few and far between. Most surfers get a kick out of seeing him in the water and like you mentioned in another post one minute there is no one on the beach and the next your too busy fielding questions to actually catch any waves.

Having the extra cell really makes a big difference when your trying to surf real waves. You have the power when you need it to get out of the way, shoot around a section or get some huge air. Check out the sealing set up I mentioned in the other post and you should be good to go next time you venture out in the ocean.

Your definitely on the right track Alex. Good luck with everything.

Dave