hi,

Im looking for a nice 550 motor and i cant seem to find alot. are car motors the same size?

Car motors are 540's, just about the same, but 550's usually have a fan on the end of the brushles to help cool them off. Car motors are not generally used in boats. The plastic end bells tend to melt.

oh ok ty, do you know of any rescources to find some fast 550's?

The Graupner speed 600 7.2V motor at the bottom of this page has 20K rpm and would be good if you are running one 6 or 7 cell pack in your boat. If you are running two six battery packs then go for the 12V motor near the bottom of the page. I would recommend Offshore but he is out of the 600 race motors.

http://www.hobby-lobby.com/speed600.htm

no i need a 550, ive got a super hawaii its slow as can be, its got twin 550's and they are hooked up to a gear box so they have to be the right size. Thanks for you help tho

O.k i cant find good motors for the life of me. i test fitted a car motor in my boat and it fits, is there a way to cool it so the plastic end bells dont melt?

If you run 14.4v, look at the Graupner Speed 600 8.4v or 9.6v. I believe the 12v motor is more suited for scale/slower speeds.

You can water cool the brushes. Go to offshoreelectrics.com and look in the tips section.

Ryan

ok thanks but once again i cant use the 600 graupner because its too big.

I am pretty sure it will fit. The bolt pattern is the same. What boat are you putting it in?

In most cases a 550 can be directly swapped for a 600. I believe my 550 is less than 5mm ( 3/16" ) smaller than the 600. I doubt it will make that much of a difference.

Ryan

Some kinda low "load rpm" with these motors. do they mean load with a prop?
alot of things are confusing me...

Graupner 6311 SPEED 600 BB SP 7.2V Motor:

free rpm; 28,100
load rpm; 9,400 (!?) sounds very low

i have these motors. and on the package it says 21,200 rpm... (7,2v)
now where do they got the 28,100(8,4v) from?
i know the mat and its impossible to go from 21000 to 28000 rpm with just 1 more cell

Load can be anything that will put a certain amount of resistance on the motor. In the case you are reading, they are talking about an airplane prop. Air props will load up a motor to a much larger degree than cars, or even boats.

Also that specific motor is a lower wound higher current draw motor that will spin many RPM's but suffers in torque. There are many reasons to the numbers that you are seeing.

I'm not sure about the free RPM staed on the site vs your box.

Ryan

Ok thanks guys but I have absolutley no space (not even 3/16) between the motors on the gear box, unless i ripped out the drive system and reworked it i can only put 550's in the boat. I did notice the emax has a 550 motor, will that give the boat enough speed?

Could you tell us what boat you are talking about and post photos of your current setup?

Hey, I cant post photos right now, I'll try to get them up later the set up is two 550 motors the pinions are on both sides of another gear wich is reversed then it turns the prop. (i know it sounds confusing)

How fast do you want it?
I modified a Super Hawaii for my friend who was running two modified 12 turn doubles 540 car motors in it for 26 mph. Which is a perfect speed for handling. (the boat has all stock running gear) The motors had brush coolers and motor plates all water cooled that I did. Running a prather 220 with stock drive train.

The problem was the 43 amp constant draw on the batteries. I just installed the new 12 turn 550 traxxas motors for the new rustler etc. I powered them with my left over EVX 14volt E-maxx speed control. I ran the motors in series so both motors would get 7 volts each. this worked well the amp draw dropped to 16amps per battery. (eve uses two battery leads combining the voltage in the speed control) So batteries where cool and the motors after two minutes run time at full throttle were cool to the touch. They were only using the cooling motor plates on the front. I didn't clock the speed on radar but it was very nice and the boat handeld even better without the dreaded spinouts when turning.

I am next going to try the Traxxas titan e-maxx 23 turn 550 motors which are wound for 14 volts. I already use them in the fighter 550, the Baltek (mini Hawaii) and the MRP Phantom cat all on 7 volts and the move them all in the 18-22mph range. They have more tourque and more rpm so I will up date you as soon as I get the time. (just got out of the Hopital) I still have time before the lakes freeze

I would try the traxxas 23 turn tritons if you want a drop in solution the are $23 at your LHS

Regards,
Chris
PS the 12 turn 550 from traxxas are also 23 bucks

Have you mesured them? The 550 with torque rings just touch and still give plenty of contact for the pinion gears to mesh but if the 600 is slightly larger in diameter the no go with out different pionions to make up the distance.

Chris

ryan, I am having a hard time believing air will load up a prop more than water. Water is thicker than air. So how can air load up a prop more than water?

hey i got pics!

http://i57.photobucket.com/albums/g2...ic001005-1.jpg
http://i57.photobucket.com/albums/g2...tpic001006.jpg
http://i57.photobucket.com/albums/g2...tpic001008.jpg
http://i57.photobucket.com/albums/g2...tpic001009.jpg

the traxxas titan marine motors are nice for the price

really? what would the est. speed be?

I bleive 30's but I will swap motors this weekend and test it out.
Chris

cool, ty.

You can not compare an air prop vs water prop in one medium. Obviously air will load up an air prop much more than a water prop and water will load up an air prop much more than a water prop. I asumed everyone understands this as we experience and feel it in everyday life.

I was basing my comment on the figures listed on the site with one specific motor. The purpose for larger 700 motors on planes is to spin a large air prop at low RPM (usually around 9000RPM or so) to produce maximum static thrust. In fast electric boats we don't need thrust over speed, so we use a smaller water prop with high pitch ratio's vs a large water prop with low pitch ratio's to achieve high RPM(>12 000RPM) in most cases and speed.

I'm not sure why or what you're having a hard time believing. I can place any water, any air prop on one specific motor and say either medium will load up the motor more. Completely depends on what application the motor is best suited for.

Ryan

Ryan I'm confused.
Are you saying that if I stick my 10x4.5x4 GWS prop in the water it will load the motor less than if I run it in the air?

The vicosity of water is vastly denser than air. The apm draw on the air prop in the water would kill the motor and the speedo.
An airplane prop at speed uses less amps to maintain speed than a boat prop in the water uses to maintain speed.
that's why boat are so hard on electric setups.

I a person walks through a body of air he will expend less energy and move faster than if he was walking through a body of water.

Chris
Yah know This ins't comparing aples to apples since hydrodynamics and aerodynamics behave in different ways so eveny my logic I fear is faulty