RC Crocodile help?

[Ykick]

'buddy wants to power a foam prop Crocodile - some sort of RC boat or sub can probably be adapted but don't need or want high speed. And while searching around I found one on youtube:

[youtube]naMpnic2tRw[/youtube]

He asked me for help because he knows I buy stuff from HK (hobby king) but I never deal with true RC gear - any ideas from those with RC boat experience?

 

[Drunkskunk]

Sounds like a cool project. I've been messing with R/C for 30+ years. There are as many possibilities as there are ideas.

But its hard to recomend something with out some details. Size, weight, drag, speed, how deep the prop will run, what kind of water conditions, what the inside of the hull (crocodile belly) is built like, and what his performance expectations are.

For the most part, HK's selection for boats sucks, there are better places to look. Something like this might be a starting point: http://www.funrcboats.com/ProductInfo.aspx?productid=GR1139
that would power a 2 foot, 2 to 4 pound boat with the drag of a tugboat's hull through the water. I have no idea if it would meet your friend's needs, but it's a starting point to design a system from.

 

[spinningmagnets]

Sounds like a fun project. I'd make the propellor ducted and covered with a screen also, to lessen the entanglements from underwater vegetation. You might even consider a magnetic coupling between the motor and the prop. The final drive would spin an X shaped device with strong magnets attached to it (N, S, N, S...), there would be an aluminum or stainless steel plate (non-magnetic) separating the airtight motor compartment from the water...

and outside in the water the spinning magnetic flux would spin a similar X that is made from ferrous steel (encased in an epoxy disc to eliminate water churning and corrosion?), and that would spin the screened-in and ducted prop...

Just some thoughts, I don't know if it would work or not.

 

[Ykick]

Gotta love this place for insight to unusual applications - thank you very much for the helpful replies!

I found this place called Dumas and they carried some low speed motors and many slower moving model boats. 'think I even saw something about those magnetic coupled drives? And I also took a look at ROV builders and saw where some have adapted sump pumps and other cool drive stuff. More ya learn the less ya know...

The Croc is about 31" and floats. It has a concave bottom so in theory it could simply sit on top of a low-slung boat. He intends to use as a gag for visitors and around the NY ocean marina where he's a live aboard. Some talk of adding a camera later on down the road.

Totally fun and recreational thing but it would give us both a chance to learn more about the gear RC folks use.

Thanks again and I'll try to add our own photo if this ever get's off the shore!

 

[Kingfish]

Needs glowy eyes for night time fun!

Cool gag of the week award 8)
~KF

 

[Ykick]

Needs glowy eyes for night time fun!

Seriously tempted to do a Luke flame thrower mod...

 

[Kingfish]

Needs glowy eyes for night time fun!

Seriously tempted to do a Luke flame thrower mod...

Better said than done; I hear you though! :wink:

Too bad it is a wet environment, else you could try something like this: Tiki Head Flame Light

I saw something like this put to great effect at a Hawaiian bar 8)

Q: Have you ever seen a "woman-eating" version of a crocodile? Just askin'
Swimming the other way, KF

 

[Ypedal]

needs soft rubbery legs to flap around, .. and flame thrower would totally rule !!!.. 8) '

or a paint ball hopper !

 

[Ykick]

I agree Y, 'needs more leg and actually tail movement for maximum realism - fire breathing would be something though, LOL... Paint ball's a good idea too!

Woman eating version? Damn, we're thinking the really weird stuff now...

1st thing's to get something working and like most projects, go from there!

 

[spinningmagnets]

Tail needs to slowly wag, easy to do...

 

[Drunkskunk]

Wagging tail would be cool. I built a boat once that worked by wagging a paddle side to side. it was slow but fairly power efficent.


breathing fire would be epic. Might also be cool if it shot a jet of aimable water out it's mouth.

 

[Lock]

If ya use an underbelly screw drive buddies croc could operate on land too:
http://www.youtube.com/watch?v=afJ18eJeNgU
[youtube]afJ18eJeNgU[/youtube]