MX429

I wanted to share some of my project that I have been working on. When I was a kid, I had a Nikko challenger V boat. I got it brand new in the mid 80's. It was such a cool toy. It wasn't very fast at all on alkaline batteries, but it did go a little better with Nicad batteries. It was one of my favorite RC vehicles ever, but like many things from your childhood, they run their course and fade away.

With an Internet search a few months ago, I found a new one in the box. I knew that I needed to buy it and make it what I always wanted it to be....fast!! I ended up buying it and a Nikko Jet Tornado which is the later version of the same boat. I will be converting it as well with a slightly different set up.

The Challnger V has a traxxas 21T Titan motor powered by a speed control from an old emaxx truck. It supplies 14.4 volts to the motor. It's controlled by a spektrum 3 channel receiver. After a cooked motor, I also added water and fan cooling.

I am not sure if it would be considered "fast electric" but it is certainly much faster than it ever was originally.

http://youtu.be/zUHZvWCa1F0

MX429

crispyspa

Sure does move right along.

n.h.schmidt

I may have some suggestions.First A couple of questions. Are you running 12 cells in the boat? Are you using the stock prop? It looks like it runs nicely but, you should get more speed than you are for 14.4 volts
n.h.schmidt

MX429

Yes. I do have two 7.2 packs in the boat.

I tried a couple different props other than stock. I had to buy a different drive shaft and cut it to length. Both of the other props were too much prop for the boat. It could not turn enough rpm with them. I feel that the submerged drive must make the props much harder to turn. The boat also did not turn well with the larger aggressive props.

I I ended up going back to stock.

MX429

MX429

I thought the big prop was going to be a good change, but it was not.

n.h.schmidt

You do not say what size props you tried,or the make. When it comes to submerged drive ,bigger isn't usually better. Is your new prop shaft 1/8"? Or maybe 4mm?
Also lighter= more speed. If you went to two 2S lipo batteries or a single 4s lipo pack you could save a lot of weight .Longer run times too. Cheaper than nicads .
You are on the right track on cooling the motor. If you soldered copper tubes to the motor terminals and ran water through them,your cooling would be better.
n.h.schmidt

MX429

http://www.offshoreelectrics.com/pro...?prod=oct-1240

http://www.offshoreelectrics.com/pro...od=grp-2317.40

http://www.offshoreelectrics.com/pro...?prod=ose-1310

Those were the props and shaft that I used.

n.h.schmidt

You don't have enough power in that motor for a submerged prop of 40 mm. You did good with that prop shaft though. That shaft allows you to use the Graupner K series 4mm threaded props. They have a lot of them between 29mm and 45 mm in size. You would be better served in using a K33 or K35. Check with Offshore Steven should have a good selection. I will check my own stash of K series props. I used them a lot. There is a better motor for what you are doing. Kyosho used to sell a 19turn long can motor called a Magnetic Mayhem. It has good magnets and replaceable brushes like the car motors. You could likely get one on ebay. I used them on somewhat larger or heavy boats. Easy to cool the brush hoods too.Really helps with the burnout.
n.h.schmidt

MX429

Thanks for the information. This whole thing has been trial error for me because I had no idea what would work together. I had no idea what prop to choose.

n.h.schmidt

I looked and found a Graupner K series Carbon prop 34.5mm. If you pm me with your address I will send it to you for the low low price of free. I have a few extra goodies to add to that. I have been at this for a long long while. My special delight was making dog performing boats become raceworthy.
n.h.schmidt

MX429

Wow. Thank you. I will send a PM now.

n.h.schmidt

I'm sorry that I haven't sent you the props yet.I will do so soon. Are these two boats all you are working with? If I knew the direction you are going , I might have more goodies that could help.
n.h.schmidt

MX429

Yes, two boats. One boat (the black tornado) is just a nice running cruiser with good run times. It is good for my kids to drive around and have fun with. It has a 8.4 pack and an HPI 550 motor. It runs better than stock and is just a fun cruiser.

The white boat is the one that I am pushing a little harder to see what type of speed I could get from it.

n.h.schmidt

How long are they? How wide?
n.h.schmidt

MX429

They are about 21" long and 9.5" wide

Ryanwilsonlb7

I am extremely thrilled i have found this thread! my first ever rc boat when i was a little kid was the nikko gammaray, basically the same boat just different hatch/cowling. i still have the boat after tons of abuse, let out in the sun etc. awhile ago i pulled a threaded 4mm drive shaft out of a cheap broken boat and cut it to length, installed a 37.5mm prop (not sure why i picked that size but might need to change it after reading this thread). it has a graupner 600bb motor with proboat esc i think 30a? not sure. for YEARS i searched the internet for others with this boat with no results, its great to see fellow rc'rs that share similar interests. im now interested in finding a new cowling for my boat (as you can see) and try to remove these sticker backings in the sides and somehow try to bleach the hull or paint it. i also should have put the water pickup on the other side of the prop to pick up propwash. still trying to come up with a better rudder system, the reason its offset like that is because at full right throw it would over extend and manage to lock the rudder to the right (if you understand what i mean). great to finally have a thread on these dinosaurs.

i just noticed yours has a direct drive! i need to work on this thing, how ill change the angle of the motor im not sure! lol and i wish i didnt break the servo hold down as i wouldve liked to do mine the way you did yours.

sorry for the sideways pictures

MX429

That's cool Ryanwilson. I knew someone else must like these things.

nhschmidt sent me a couple props that I am going to try soon. thanks!!

I will post back as soon as I get the opportunity to try them out.

Ryanwilsonlb7

found some info on the graupner eco speed which is a similar boat, it uses a graupner 32mm 3203 series prop. found a 37.5 and 40mm 3203 series in my parts bin, they have a .8x prop diamter pitch.

Ryanwilsonlb7

Scraped those decals off and then sanded and painted with a can of paint I had laying around, swapped the 1.6px37.5 for a .85px37.5 prop. Not perfect but better than before

MX429

I worked on my challenger V tonight too. I cut a new driveshaft to work with the props that nhschmidt sent. I hope to try it out this weekend.

That paint looks good.

MX429

I ran the boat today with one of the props that nhschmidt sent.(thanks!!) It doesn't come out of the hole as fast but is faster on the top end. The motor gets hot if I am not careful with it but it is the fastest it has ever been.

n.h.schmidt

You are welcome to the props. What prop did you try? You can help with the heat problem at least a little .If you solder tubes to the motor terminal tabs and hook up your cooling line to them . There is several problems in getting these boats to run better. The hard plastic hull is heavy. Much of the weight is too far forward and the boat runs too wet. If you had a gear reduction ,you could use the bigger props without burning the motor. There are brushless options that would work and be cheap too.
n.h.schmidt

MX429

I tried the M4 33mm, 46mm

Weight is an issue with this boat. With the two 7.2 packs, it is quite heavy. The extra power is what makes it fast, but the weight is dragging it down.

The black boat is set up with just one pack and it is very noticeable how much lighter it is and how it sits in the water better. With just the one pack and the HPI motor, it is not as fast but is a neat little "cruise around the pond" boat that anyone can drive and not get it hot.

Maybe be I need to think of a different set up altogether for the yellow one if I hope to get more performance. With the current set up, I am pushing this traxxas motor to the limit for it it can take. After a couple of speed runs, it gets hot.