hey fun4ej, try these motors for your cat, they should bring it up to 40mph with two 7 cell packs in parallel.(don't try series, it might blow them)
http://www2.towerhobbies.com/cgi-bin...&I=LXNMM6&P=ML
these are different than the ones that you have, because they are 12 turns instead of 19 or 20.

sorry not 40mph. Those are stock "low turn" motors.

um, actually, the cars that these come in go 35mph out of the box with a 7 cell battery, so if you use 2 7-cells and the right props it'll easily do that.
http://www.traxxas.com/products/elec...trx_bandit.htm

Last time I checked boats don't have wheels that roll freely on the ground. Brushed 550's will get you maybe 25mph. No where near 40mph.

Ryan

ok. cars have 0% slippage. wheel has a circumference of 8 inches, the tire will do a complete rotation and cover 8 inches of ground.
boats typically have 25% slippage. also a car motor and boat motor differ.
I doubt it will even do 35mph

I don't understand how one could even compare a boat to a car.

My .15 size stadium truck does 47mph. My .45 size boat does 44mph. 3 times more power and not even equal in speed.

Ryan

and your .45 AND your .15 size boat have very low rpm,(especially if your using a marine motor) and your .45 sized boat needs that much power because it is very large. Now, take your .15 boat, and put two racing .21's in it. That's what it would be like with the NQD cat ant the 12 turns compared to the stock nqd.

If you would have read correctly my .15 is a car engine in a stadium truck. How you know it has low RPM, is beyond me.

For marine application, typically a sport mono runs around 20 000RPM, a cat or tunnel around 20 000-25 000. With these ranges, a suitable prop with enough diameter may be used.

Just so you know my .45 boat is an Outboard Tunnel that is 33" long @ 44mph. You are telling me 2 12 turn motors in a 31" cat is going to go 40mph and keep up with my tunnel? Two inches is not a large difference, and 2 12 turn motors vs a nitro .45 is.

Another fact I'd like to point out (it doesn't sound like you have a lot of boat experience, at least with outboards) is an outboard motor is no way as efficient as an inboard setup. Also putting 2 motors with two outdrives in one hull is slower then one motor. Another motor only increases thrust, not speed. The drag of the extra drive and prop only slows it down if it can not use the additional thrust. Light hulls (all we use for FE) don't need additional thrust.

Ryan

Woohoo this discussion is really begining to heat up.
I have been in this (FE) game for less than 6 months and have learnt a few things.
Car motors and boats are not the best recipe for speed.
Nitro is not my thing but i do know a bit about it, btw, i.c engines, I know lots about!
Two smaller (or car ) motors on two props in FE will not beat 1 decent motor on 1 prop.
This I know as my cat has 2 motors and 2 props and out of the hole will whip my tunnel and mono but down the straight is at the back of the pack.
I have said it before and I will say it again.
Listen to the people who have demontrated real knowledge AND experience , despite some of the sh1t slinging that goes on between them I respect the opinions of a few here. I will not name them but they know who they are.

I'm just going on the fact that electric motors have more torque than a similarly sized nitro motor. And a 12 turn motor usually has alot of rpm, so it should work. And what kind of st do you have?

How is the even possible?
How can you compare a electric motor to a similar sized nitro. Are you talking in actual size like dimensions? because if you are then forget about it.
Two 12 turn motor will not get you as fast as a .21 boat. I have no idea where you pull this stuff out ( i have a good guess however) but it is just so wrong its not even laughable.

Life is hard. . . compared to what ?
12 turn motor has a lot of rpm. . . compared to what ? You can't just say these things and expect it to be.
if you want to discuss nitro stadium trucks i suggest you take it to the forum.

This is the forum, and by size comparisons i mean a 540 to a .15. And yes, i do get these comparisons from cars. (i'm just asking him what kind of truck he has b/c i am interested)(i don't really want to discuss it.)

I am thinking a nitro conversion would be interesting. It would need to have a mount fabricated, and possibly gear upgrades or standard propshaft...but what size engine would you put on this?

With the lower unit in stock form I was thinking an .09? I have a throttled Cox .09 I wouldn't mind seeing in one of these. Not sure. A .15 was mentioned for comparable power, but could the lower end take having a .15 nito added? If that is the case, the Cox .15 would be even cooler.

Are the gears metal to start with or are they plastic? Would there be any type of RC Car gears around that would be steel and work good? Is the down shaft a flex or is it solid? What kind of end does it have to think of a coupler and flywheel.

It would be nice to have one on the bench to see what would fit up to it, maybe even using a K/B 3.5 propshaft assembly to start with.

Does anyone have pics of the parts or a discription of these that could help?

I wouldn't mind going out of my way to build a decent unit even if I had to customize a few off the shelf items to do it.

I think the size of it fills a hole, and I have an engine or two I wouldn't mind seeing used in an outboard.