Novak 5800 vs. other brushless motors

[OptimaMan]

Hey guys, I just got a brand new Novak SS5800 and I opened it up already (I haven't even run the darn thing). Interesting... The rotor diameter is pretty small - definitely smaller than a Lehner Basic or Hacker 50 series motor. Possibly similar in diameter to Hacker c40 or Lehner 15 series... or maybe 1 mm larger than those. The rotor is longer than a basic series though but not quite as long as a basic xl.

Anyway, the kt of the novak is .45 in oz per amp. Just doing some research and my Lehner basic 3100 has a kt of 10.55 Ncm at 36.78 amps... so doing a little math: that is .2868 Ncm per amp.

2.54 cm = 1 inch so this number than becomes .1129 N inch per amp

How do you convert newtons to ounce? Well, 9.8 newtons = 1 kilo x g
2.26 pounds = 1 kilo = 36.16 ounces

so the ratio is 10newton=36 oz. If you figure that, the Basic 3100 has a torque constant of .406 in oz/amp!

Hmm.... I wonder how accurate these figures are...

Coming soon - comparisons between these with a propellar - will measure RPM, watts input etc....

[Signats]

Well I have both of these motors and have run each of them in an Associated T4 stadium truck, and in a Radio Shack:eek: Ricky Carmichael dirt bike.

It is obvious after running both systems in each vehicle that the Lehner motor published specs. are for a motor that is under load, and the Novak published specs. are for a motor that is not under load.

In the T4:

On 6 cell GP3300s the Novak has higher top speed, shorter run time (about 12 min.), and gets much hotter.

The Lehner (geared much taller) is a little bit down on top speed, but still has more low end torque than the Novak. It has about 33% more run time and stays much much cooler.

One thing that the Novak does better is taking off from an up-hill dead stop, or if there is any kind of (dead stop) impedament to forward motion, like being high centered on a pipe, or tangled up with another vehicle. The Novak will blast out of these situations without ever cogging no matter what the state of the battery charge is. The Lehner is being run with a Schulze 18.61K controller, and the receiver is hardwired to the main battery, and it will cog a bit in dead stop situations where forward progress is impeaded, especially when the battery is in the last 1/3 of it's life. If pinned, square on, into a barrier the Novak can be made to climb the wall and then let off the gas and the truck will roll backwards far enough to drive away, the Lehner won't really do this with only 6 cells.

In the (7.5 lb.:eek:) Dirt bike:

The Novak gets really, really hot and has about 7min. of runtime, I have had it thermal when the ambient air temp. was 38*F (on a very high traction surface), and if I gear it so that it won't thermal the bike looses too much speed off the top to be fun anymore. The Lehner gets around 12 min. of runtime, has much better acceleration, and stays way, way cooler, top speed is about the same with either system (about 30 mph), but the Lehner gets there qicker. Cogging is not an issue in this application because the only time the bike is going slow enough to cog is when it is laying on it's side anyway.

What I really think:

The driveability award goes to the Lehner, the low end torque is just better, and it is every bit as smooth if not smoother than the ss5800, it is also far more efficient and able to power heavier vehicles without balking. With a little more voltage I have no doubt that the small top speed and (impeaded) dead stop cogging advantage that the Novak has would all but dissapear.

Novak is better for getting out of sticky situations, it never ever, ever cogs, however, it is also a less robust system and mine has been sent in for warrenty work several times. Novak has quickly honored the warrenty on every occasion but I would perfer to not need to repeatedly send it in for replacement/repair.

I like driving either vehicle better with the Lehner/Schulze a bit more than with the Novak, the power delivery just feels more "right" to me. The Novak has not earned my trust as far as reliability goes, it is a very good system, for the price, the customer service is top notch, and it has a very smooth and broad power delivery. You can't really go wrong with either system, my prefrence is for the Lehner, it has more torque, reliability, efficiency, and versatility. It costs more but IMHO it is worth it.

As always YMMV

[jocktheglide]

hey signats did you modify your ricky bike?? I thought was considered a toy and cant upgrade it? I know they were super popular during christmas time and limited and folks were selling one bay for 200 dollars and I saw some at radio shack for 100 dollars.:D

[Signats]

JtG,

The Ricky Carmichel bike is a RC grade vehicle, it can be upgraded in many ways, I have upgraded the electronics, suspension, steering, tires, and motor. Now it can clear some of the big jumps at the local BMX track and drive away clean, it rips in the dirt, on the lawn and even in parking lots.

Find out more here:

http://www.rcgroups.com/forums/showthread.php?s=&threadid=187142

See some video here:

http://www.rcgroups.com/forums/showthread.php?postid=1802039#post1802039

There is also a review on the Wild hobbies site

[OptimaMan]

That's odd.... The only handy motor I had was the Basic 4200. I put the Novak 5800 with 6 cells first and with a 6x4 propeller, the thing was spinning at 16000 rpm and sucking up 175 watts of power. The Basic 4200 was spinning at 20000 rpm and sucking up 275 watts of power. Funning thing was that at 20,000 rpm, the voltage drop of my battery was down to 4.1 volts!!!! But, how does a 4200 rpm/volt motor sping at 20,000 rpm on only 4.1 volts???