Why do I want brushless?
 

I have a brushless setup on the Easy Star, and brushed on the Super Cub. I had brushed on the Slow Stick, until my lack of skill destroyed the first motor, and I replaced it with a brushless setup.

I notice that whenever anyone posts something about a plane with a brushed motor, someone (usually several people) always posts "you can easily upgrade that to brushless."

My question is "What's the advantages of brushless, beyond more power?" I mean, if modeling fighter jets and stunt planes, if would be an obvious choice, but why for park flyers? No one is doing 3-D acrobatics with a HZ Super Cub (I hope, anyway) and it seems that few people are racing Slow Sticks. In addition to their greater power, are they more efficient, providing better battery life? Do they last longer?

I'm very much a newbie, so don't feel like you're talking down to me, and don't assume that I understand the basics, as I probably don't. Just give me your thoughts on why brushless is better.

Well they are more efficient and they do last longer. No brushes to wear out, they are lighter than their brushless equivalent and give you more power when needed most.

Other than that they are pretty much the same! lol

If what you have is working for you then great! Leave it the heck alone. Now if you burn out the brushes on that motor and need to replace them you may have a hard time finding parts. Not much is sold for brushed stuff nowadays.

The cheapo mass produced "can" motors you are using are not (as Bill points out) very efficient. While you can find high quality brushed motors are actually more efficient than brushless.

I agree that the biggest downside is the brushes wear out (sometimes quickly) and they tend to be heavy, have gearboxes (so more moving parts and weight) and no longer have a cost advantage.

So you can save weight, have fewer moving parts (with outrunners) and longevity. Now they are as cheap as brushed. They are MUCH more powerful for their weight compared to brushed. Another great feature.

So why not?

Mike

...plus, at least in theory, a brushless setup generates less RF noise.

Easy to answer.

Some 10 years ago I built scratch built a 150% version of the popular Electrostreak that was popular in the late 1990's. Still have this plane, and it was designed for easy conversion between different electric motor power systems.

The original power system was an Astroflight Geared 40 brush type motor, with 22 Nicad cells for battery power. That setup worked with a 13X10 prop, and got about 3-4 minutes flight with a battery charge. Climb out was at about 30 degrees or so at full power. Both the motor and the Nicad battery pack were so hot after a flight that I needed a fan to cool the motor and battery pack down before recharging the battery. This brush type motor needed new brushes after about 50-75 flights. And after several seasons of flying, I had to turn down the Astroflight motor commutator, it got out of round.

Next, that Astroflight brush motor was exchanged for an Astroflight geared 40 Brushless motor. Performance was noticeably improved, and flight times went to about 5 minutes, using the same 22 cell battery pack. That Astro motor used a brass pinion gear, with the driven prop shaft gear made out aluminum. Even running completely sealed in a high grade type of high speed gear grease those gears needed to be replaced after about 30- 40 flights.

Now, that same model is equipped with a Hacker A50-12S motor and a 6S2P A123 battery pack. This cut near one pound of dead weight out of the power system. Flight times are around 7 minutes with a 2 minute reserve. And the flight performance has changed from OK to astounding, where the model is able to climb out at 70 degrees and keep on going. This power system turns a 14X10 prop at 8000 RPM. This A50-12S motor has double the horsepower of the Astroflight geared 40 Brush type motor. (And nowdays, that $$$$ A50-12S motor is 1/3 the cost of an Astroflight Geared 40 brush type motor!)

I've got eight Hacker motors, most of which are on their fifth year of flying. And now, all of them perform like they did new out of the box.

As far as radio frequency noise on the Astro Brush type motors, this becomes a real serious problem when running 72 Mhz radios, especially with over 20 Volts DC on the motors. I had an Astroflight geared 90 motor ten years ago. With the original setup, it got a radio range of 10 feet. With the transmitter antenna fully extended!!!! Took a lot of effort to reduce that RF interference to acceptable levels. The solution was several one inch diameter ferrite toroid chokes on each of the motor wires.

Fantastic information, guys! More power when I need it, better battery life, less chance for interference and greater longevity. Now I know some things that I didn't know yesterday.

That's what these forums are all about! Don't hesitate to ask anything else you may want to know. We have a real friendly group here that do not tend to flame new folk for asking questions!

Glad we could all help you out a bit.:)

As others have said, brushless motors last longer. What they didn't say is that all there is to wear out is the bearings and they are easy to replace.

Now crashing can damage anything from the shaft to the case.....but barring that, bearings....and they usually last a long time.

Besides that, you can find brushless motors and esc'c CHEAPER than brushed motors and esc's now.

No need to change out a perfectly working brushed motor, but no reason to purchase another one either.

And, if you need more reading information :D

Thread on 70 size glow engine conversion to electric
http://www.wattflyer.com/forums/showthread.php?t=45222

Hacker 6S2P A123 powered Models
http://www.wattflyer.com/forums/showthread.php?t=44686