Micro R/C boat

Brettos · Dec 30, 2005

I am thinking of making a micro boat 300mm - 12".

It is a kit boat, they cost $29.00AU.

The engine is a pro slot car engine, not cheap at $189.00AU.

These engines are small enough to fit 4 in a matchbox.

They are 12volt rated and when running they sound like a psyco dentist drill.

They whistle when running.

They have a balanced armature, ball bearing races on each end of the shaft and quad cobolt magnets.

The boat is all balsa, with a clear molded plasic cowl.

What do you think?

Regards Brettos.

Andrewg · Jan 2, 2006

Brettos

I have made a few aeroflytes - the hull will work - however is neither hydro nor tunnel - the tunnels are better if you widen the marginall and lower to tub a little to lower CoG

The motor is wrong. You need a torquey motor which has rpm of about 25000 under load which will match the available props. (easy to get efficient small props are 30mm). A boat will pull max amps all the time. They are very hard on brushless motors.

If you want a good motor get a Graupner 400 6v (70g) motor and use 2s or 7 cells - something that will give you 18 amps continuous without dropping voltage too much. Get a small 25-30 amp controller.

You can make your own hardware - modifying electric hardware is ok if you can get secondhand old style Fullers and cut it way down or make your own.

Rogue · Jan 31, 2006

Hi Brettos,

I made one of those about three days ago and still having fun with it

I got the Dictator (the black one) $27.00

I put in a Groupner speed 400 7.2 (?) volt $18.00 (wich I already had)

A brass rudder setup $12.00

A 3 blade 30mm prop, tube and shaft $10.00

I used an old servo I had, the esc and receiver for my car and I have 2x7.2 volt batteries that were for a mates helicopter (very small in size).

I mounted the center section of the hull (sorry for no lingo!) higher to account for the extra weight.

Its really funny to see it go, turns on a dime, accelerates very quick but I would like a bit more top end and minimal chop on the water makes it very hard to not dive under :lol:

I only bought it to paint and sit on the shelf, but its so much fun!!

I anyone has ideas tomake it go fast I like to hear them

dyrodium · Feb 7, 2006

I got one of these boats too! I got the "challenger". Do any of you have a picture of how you layed the insides out? Could use micro servos or are they too weak?

Thanks

Andrewg · Feb 8, 2006

with the hull make sure your centre of ballance is 28% from the transom of the hull , also the prop is probably a submerged prop and partially surface piercing so not running at optimum nor delivering possible speed.

Also which cells? You may only need 7 rather than dual packs

If you can send me a pic at [email protected] I can help you out with this one. It was my first fastelectric - initially it wasnt rc and ended up very modified but with really cheap stuff. Eventually the unstoppable hit the immoveable at high speed and made a spectacular exit from this world

Andrew

[email protected]

Rogue · Feb 9, 2006

Hey Andrew are you saying you can get these to go quick?

Tell me more!!!

Rogue · Feb 13, 2006

Hey Brettos I finally got some pictures of my setup in my gallery for you. Probaly not the best way but its all I could do lol.

https://www.intlwaters.com/gallery/index.php?cat=10243

SCOTT WITHERELL · Mar 7, 2006

hope to finish it soon,16in long ,8- 1/2in wide,like to put a mamba system in it,( if it dont work ill make trophies out of it'''LOL'''.

scott witherell.

P.S. like to see more micro hydros,

Speed Jr. · Mar 8, 2006

keelhulled said:
hope to finish it soon,16in long ,8- 1/2in wide,like to put a mamba system in it,( if it dont work ill make trophies out of it'''LOL'''.

scott witherell.

P.S. like to see more micro hydros,

That looks really cool!!! Always wanted to build somethin like that, never got around to it.

Larry Jr.

direwolf · Mar 9, 2006

Any recommendations for a shop that sells these?

SCOTT WITHERELL · Mar 10, 2006

just started to make that 16in micro hydro out of fiberglass. plug 95% done.

oldlugs · Mar 17, 2006

Brettos said:
I am thinking of making a micro boat 300mm - 12".

It is a kit boat, they cost $29.00AU.

The engine is a pro slot car engine, not cheap at $189.00AU.

These engines are small enough to fit 4 in a matchbox.

They are 12volt rated and when running they sound like a psyco dentist drill....What do you think?

Regards Brettos.

As someone who raced those slot motors for a while, I can tell you that they are fairly torquey..! (they power the world's fastest accelerating wheeled vehicles) Problem is though, they'll still need to be geared way down, just as they are in the slot cars... Those motors with open class arms in 'em turn around 150,000+ RPM! I think you'd have a tough time keeping them from burning up in a boat... Could be a fun experiment in a 12" rigger, but they do suck a few amps, and they do run hot. Open class slot cars are always moving at 40+ mph, and motors still get cooked, requiring replacement several times in a race. They're meant to go really fast for a few minutes, powering cars that weigh only a few ounces.

jayt · Mar 17, 2006

That's interesting information, few of us have played with slot cars for awhile (in my case over 40 years!). Clearly these motors would have to be geared significantly to live in a marine application. I think that a better idea is to use a 280-size airplane motor (0.78" OD). These are readily available in a multitude of Kv and torque ratings, both brushed and BL.

oldlugs · Mar 17, 2006

jayt said:
That's interesting information, few of us have played with slot cars for awhile (in my case over 40 years!). Clearly these motors would have to be geared significantly to live in a marine application...

In the slot cars, opens (fastest motors) are typically geared around 5:1. From a dead stop, they'll go down a 70' straight in under a second.... They're not the slot cars of 40 years ago..

If you're interested, have a look at the Old Weird Herald site's forum. The 1/24th scale cars are about the fastest, with the open class "wing cars" being the fastest of the bunch; something like a twin 90 rigger in comparison.

DarthRigger · Mar 18, 2006

Brettos said:
I am thinking of making a micro boat 300mm - 12".

It is a kit boat, they cost $29.00AU.

The engine is a pro slot car engine, not cheap at $189.00AU.

These engines are small enough to fit 4 in a matchbox.

They are 12volt rated and when running they sound like a psyco dentist drill.

They whistle when running.

They have a balanced armature, ball bearing races on each end of the shaft and quad cobolt magnets.

The boat is all balsa, with a clear molded plasic cowl.

What do you think?

Regards Brettos.

Where do you get these little boats? Is there a web site?

Andrewg · Mar 18, 2006

re slot car moors - not enough torque - measure the Nmm - zilch comapred to a 28 or 35mm dia motor. Wear rates horrific. ALso boats weigh upward of .6oogm and run in a medium 16000 times as dense as air - the parasitic drag is relatively huge. Add to that huge cost relative to a $15 motor which will run for years or a brushless system for less than $100

the hulls are aerofylte made in australia - they are one sort not flash but cheap

on the other hand lots of makers have micros - H&M etc

Micro R/C boat

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