Nikko Stinger Brushless Buildup

[MumblinAviator]

As you can clearly see, I'm new to the message board. I've been surfing for days now trying to find a simple little buildup project to work on as I have yet to own an R/C boat.
A few days ago I purchased the Nikko Stinger II from Toys R Us.com for about $40. It was a toss up between that and the NQD High Wind. This hull is a Hydroplane shape, 22", with a single surface piercing prop (i think). I wanted to stick with a single motor to keep things simple for the buildup.

Before I get flamed, I know I could've done alot better than Nikko, but I wanted to keep things very cheap.

I haven't yet recieved the boat, but it's my understanding that it's a platic hull which will probably make things a little heavy, but I'm well prepared to do some cutting and chopping if necessary :p

After hours of searching on Ebay for a cheap Brushless Motor/ESC combo that could push this sucker around, I decided (wisely I hope) to buy the SV27 Brushless motor and couple it with a cheap 40 Amp ESC. My thinking: The SuperVee is a larger boat and has crazy speeds out of the box, even if the Stinger were heavier, I think the SV's motor could do a good job.

I have some decent 3600 packs I'll be making into 8 cell sticks and wiring up to the ESC, so I'm hoping I made alright choices to get the boat movin'.

I'll be back posting hands-on pictures and build-up details as they occur.

If you guys have any knowledge, opinions, or suggestions about either the SV27 motors specs, or anything else I plan on doing, please feel free to speak up.

As a side note, I also have a Reef Racer 2 on the way that I plan on also making a Brushless Beast.

[Ghost 2501]

thats gonna be fun on the water :) keep us informed on this :)

[MumblinAviator]

I hope you're right!

And I absolutely will

[Rex R]

you might like the power package that offshore electrics has listed, motor specs(and esc) motor, size 540, 1600-1900kv(near as we can tell), esc 8-14cells. for that hull 8 cells may be pushing it(weight).

[MumblinAviator]

That does look like a good setup!

If my original idea doesn't work I thought about trying a brushed ESC coupled with a large 700 sized motor. Offshore says they're used as an upgrade for the CEN racing boats, so I can see it working pretty well.

There is a Graupner 700 Turbo 8.4V BB and a Graupner 700BB Super Charged both for under what I paid for the SV27 brushless.

Any thoughts?

[Rex R]

a speed 700 would be (IMO) too big & heavy(when you factor in batteries(about 1.5 lb.s iirc)) a speed 600 now... should fit nicely and provide a fair amount of punch on 6-8cells.

[no stick]

I think the NIKKO battery pack for this boat is 9.6 volt 4x4 end to end flat pack AA NiCd. If you are thinking about 3600 mAh 8 cell, are the cells sub C? If so, there will be a BIG difference in weight. I'm glad you did not go with the NQD as the motors do not have heat sinks and they overheat easily. EP racing makes better boats for what you desire to do, but then you have to modify the electronics because turning is accomplished by changing RPM for each motor.

Interesting project. :)

Ed

[MumblinAviator]

Interesting project indeed, but I'm not so sure it'll be followed through to the end.

My order for the SV's motor fell through, it's on back order for another month at Tower. So now I'm looking at getting a speed 600 like RexR suggested. It'll be ALOT cheaper.

I realize now, after all of this talk, that I cannot expect great performance out of the boat without going above and beyond my capabilities and budget... I guess that's why forums exist!!

Don't get me wrong, I'll still tear this sucker apart and see what I can do, but it might not be brushless.

Thanks for stickin with me fella's

[no stick]

Please post pictures of the inside of the Stinger II when you get it. I'd like to modify one also. The other boats listed on ToysRUs made by Nikko are 18" long. I'd like to see what the length is for the Stinger II. I've got like 8 EP racing boats at the lake for my grandkids. They are very fast with two 380 powered motors.

Tks,

Ed

[no stick]

You may be OK if the speed 600 can handle 9.6 volts (8 subC cells). The single engine boats I'm familiar with are 7.2 volt and 500-550 motors. Not the fastest in the world.

Ed

[no stick]

Wow :eek: . The SV27 motor is rated at 18 volts and requires 2ea 7.2 volt 6 cell sub C NiMh batteries which will be way too much weight for the Stinger II.

I just may have to fork over the money for the Aquacraft SV27. :D I'm glad I found this thread.

Ed

[Shaun Hendricks]

You can always half the weight and go LiPo.

[MumblinAviator]

Half the weight and triple the COST!! But yes.... that would work

ED: I too am sort of kicking myself for not saving my money and getting the SV27 outright. But I look at it this way... as long as my Wife doesn't kill me for spending unecessary money, I'll be able to use all of this as a learning experience.

The Stinger II is 23" long if I remember correctly.

And it shipped today :)

[Rex R]

nothing wrong with having a 'starter' boat to learn with/on. one can always use it as a rescue boat :)(besides the sv27 needs a good bit of running room :))
Re: motors
if you plan on running 8cell packs I'd go for the graupner model 6309 600 bb sp 8.4 motor as it wont get quite as warm but will give you more torque than the 7.2v motor.

[MumblinAviator]

Nevermind!

[no stick]

You can always half the weight and go LiPo.

Hey. I've bookmarked your NQD blog and conversion thread. Good luck. You seem to know what you are doing. I've not had much luck with my NQD's. Motors get too hot and slow way down. I've had much better luck with EP Racing boats. I use heat sink compound under the heat sinks. Are you going to use Lipos on those Cobalt 400 motors?

Ed

[Shaun Hendricks]

That's the intent. I'm looking at a pair of 11.1v 1700-2100mah 20C units on a parallel bar. Should be good for 68-84 Amps out. At 40A average max draw, they should last about 5-6 mins. Puttering around 8-10 mins. Weight would be about the same as an 8 cell Nimh pack.

I am planning to use Heat Sink compound on a large Aluminum plate that will serve as the foundation for the ESC and steering servo.

Post additional comments under the High Wind Conversion thread. I don't want to Hijack Aviators thread... (pun intended! :D )

[MumblinAviator]

I Get It!

I appreciate the curtosy though!


FLY NAVY!!

[MumblinAviator]

OK! I have video of the stock run which will be posted shortly.

The boat runs fine out of the box. It will work for a young child, but it has no speed and the turning is wide and somewhat unpredictable. The rudder and/or servo seems to get stuck time to time.

I wasn't impressed with the throttle response, it was either Full on or Full off, same with the rudder.

I was able to run the boat almost WOT for about 10 minutes...not bad.

After the run I checked inside the hull and there was not a drop to be found... also a good sign.

The exterior looks cool, and is made to look like a hydrofoil. When you look at the underside however, you notice that it is a Vee hull.

Now for the fun stuff...

[MumblinAviator]

I opened the hull to find a mess of wires connecting a small Mabuchi motor to a poorly made ESC/Reciever. The battery box was separate from the rest, which I like, as this creates less chance for water to get inside.

The shaft is just a solid metal shaft with a cheap plastic dogbone style connector glued on, and the prop is a 3 blade plastic, also glued on. At the point where the shaft meets the hull there is a large amount of grease of some sort.

The motor was encased in a plastic mount and it also had an aluminum "wing" as a heat sink. The mount was too small for the motor I had in mind, and would have be taken out.

The rudder setup looked confusing and unecessary, however after carful consideration I thought that I might be able to use the setup later on. I was right...

[MumblinAviator]

I chose to use the electronics out of a Traxxas Stampede, and an Electriflite S-600 motor. Since the motor was much larger than the 380 that came stock I decided to leave out the mount all together and just strap the puppy to the hull itself.

I fashioned an aluminum support to be placed beneath the motor allowing for the right angle for a direct hookup to the drive as opposed to the gear reduction previously used.

Once I had the angle correct I then cut the hexagonal shaped piece from it's gear and attached it to the motor shaft. This allowed me to connect the motor to the dogbone directly... It fit surprisingly well!!

I then attached two heavy duty zip-ties with screw-on ends to the two screw holes already there from the stock mount. You can see from the pictures what I was attempting to do.

Believe it or not, this also worked out really well.

For the rudder: I took the plastic piece that rotated and 'pushed' the rudder into turns, and I attached it directly to my servo. I then dremeled out a bit of the original servo mount and placed mine where the previous one went. After I screwed down the top I was able to achieve the same setup as stock, except this time my servo allowed me to progressivly turn instead of FULL left for right.

[MumblinAviator]

Stock video

http://video.google.com/videoplay?docid=-6208321708339372499

[MumblinAviator]

The only thing left to do was to extend the prop shaft.

I had read that when adding more power, the turbulence caused by the large skag reduced the props ability to 'grab' the water. I thought by extending it out a bit further it might have a better chance.

I bought a 3' piece of steel rod approx. the same diameter as the stock shaft, and after measuring, cutting, and polishing, I installed everything back the way it was, only this time you can see it extends the prop out by about an inch.

I placed a few pieces of heavy duty velcro to fit the electronics, hooked the battery up, and VIOLA!

Everything works as it should. The motor is torquey and it vibrates the hull pretty bad, I'm not sure how I might calm this down, but we'll see how she reacts in the water.

In the meantime I am currently soldering Deans plugs onto all of my electronics, so it's Modified test run will have to wait a bit.

Keep Posted!

[MumblinAviator]

Sorry, forgot these

[quicksilver]

just cut that bottom part of the skeg off, it'll take two seconds and only was there to protect the prop, which you need to change. I cant really suggest a specific prop since I run jet drives, but you need more pitch, nothing drastic, but you'll waste a lot of energy spinning that tiny thing.

Also to quiet the motor, get a piece of dense foam, rubber or even double sided tape, and put it under the motor at the point where it contacts the plastic hull. This will dampen the motor vibrations, kind of ghetto, but it'll work. Even some bunched up duct tape, anything to give separate the motor from the hull, should be like an 1/8" thick roughly. some double sided tape stuck to the top of the motor between it and the zip ties will also help keep the motor where you want it. Dont go nuts here, we dont want fires, and make sure you dont cover vent holes with anything I've mentioned.

~QS

[MumblinAviator]

"kind of ghetto"...

Is exactly what I've been doing the entire time! :) My goal has been to keep it cheap and to use whatever I have around the house.

As far as the prop, by More pitch, do also mean a larger prop?

Thanks for the suggestions

[Rex R]

if your 'dogbone' is bottoming out it will make noise/vibrate. they need a small amount of clearance( about 1/16"). a nylon washer or 2 between the hull and prop should work.
prop; think more twist to the blades, an octura x432(1.4 pitch 32 mm dia) would prolly work nicely.
edit
hmmm then again... after looking at the pics again methinks a short bit of brass tubing would server as a spacer, perhaps with nylon washer bearing.

[MumblinAviator]

I added a short piece of fuel tubing behind the dogbone as a spacer.. it offers a bit of flexibility too. I also added some thin foam pieces under the motor between it and any contact to the hull... it's worked well cutting down the vibration.

I got everything working and took it out on the water today. I started off slowly, just checking it's response, and noticed it was already going stock speed with just a twitch of the throttle.... Exciting! However, the piece I put on the motor shaft started slipping and I was barely able to make it back to shore before the motor wouldn't turn the prop any longer.

I brought it back inside and threw some extra strength glue on the shaft and put the piece back on. I'll try it again tomorrow... if it still breaks loose and spins I'll have to buy a 1/8" coupler from Tower or something.

It looks like it might run well, though. Once everything is in working order...

Stay tuned

[Rex R]

I note that tower hobbies lists a dumas complete 1/8" universal joint for about $6 usd (shipping extra). uses grub screws(I'd recomend grinding some flats on the shafts & using thread locker). sounds like it is really coming together. lets see... oh, right, almost forgot. pictures please :)

[MumblinAviator]

That's the one I had in mind, actually. Thanks!

I drilled a hole in the current piece and tried to put a grub screw in it, but the screw just stripped the plastic.... I'll need the metal one if the glue doesn't hold.

As far as pictures go... there's not much more too see than what I've already posted, but I'll get a few more up as soon as I get it running...
And a Video!

[Rex R]

couple of observations bout that u-joint; 1) be careful about how far you seat the brass bits on the shafts(they are 'cupped') which leads to 2) it will be noisy if you don't arrange things so that the dogbone can 'float' (take the thrust load off the shaft before the u-joint) (2a) don't know how much room( or shaft play) you have to work with... but a wheel collar might be needed to keep the shaft from disconnecting when you slow(or reverse).
oh and you should make sure there is no burr on you shaft ends (mine had a very tight fit(this is a good thing:)))

[no stick]

Looks great Mumblin. Now put some Hydrofoils on and get that prop to run surface drive. :D

Ed

[MumblinAviator]

Thanks for the advice, REX.

Surface would be great!

EXCEPT: The plactic piece that I glued to my motor shaft will not stay put. Too much torque and the thing just spins loose. I'll have to go ahead and order a coupler.

In the meantime, I'm throwing a Cobalt 400 into a Reef Racer... should be fun :)

[Rex R]

well someone once said, there simply isn't enough time to repeat all the mistakes, so you should learn from the past and not make the same ones :). just trying to help prevent repeats.
rex

[MumblinAviator]

and that's exactly why I chose a simple and cheap chassis to work with.... i'm just playing around with the hopes of making something fun and quick. If it works, Great! If not, then I know better for next time.