HobbyKng Scorpion motors...Astro alternative?

[Green Machine]

Has anyone considered a Hobby King Scorpion motor in an ebike application?

http://www.hobbyking.com/hobbyking/store/__17401__Scorpion_HK_5035_500_Brushless_Outrunner_Motor.html

Seems pretty good...according to hobbyking:

"Scorpion HK Series Brushless Motors are built from the best materials available, and are designed to provide both quality and performance at an affordable price. Scorpion starts with high quality aluminum alloy parts that are produced on the latest CNC milling machines. The stators are made with high quality laminations to give maximum efficiency, and minimum Eddy current losses. The stators are epoxy coated to prevent shorts, and are wound with wire that is rated at 180 degrees C (356 F). The magnets used in Scorpion Motors are rated for operation at 200 degrees C (392 F), making a motor that is virtually impossible to burn up in normal use."

Could this be an alternative to an astro motor?

 

[crossbreak]

Depending on what you want, this is an alternative. you would not be the first to try an outrunner on a bike here. Just search for "Turnigy 80-100".

Gearing a middrive is not simple. Just calc the reduction needed for a 500KV motor like you posted at 36Volts: http://endless-sphere.com/w/index.php/Gearing_a_mid_motor

You will end up in wanting a motor with around 100KV

I should add an article about "finding the gear spread needed to get hill climb ability for a given motor power"
Then you would see that gear spread gets important with lower power.

 

[wildharemtbkr]

That thing spins at 25,000 rpm on 12s, it would need a 250:1 reduction to get to 100rpm crank speed, or about 80-90:1 to get to 26" wheel speed. It is only about 2.5 inches in diameter and just slightly longer, super small, plus it costs almost as much as the astro. What's the benefit?

 

[wildharemtbkr]

http://www.hobbyking.com/hobbyking/store/__17364__Scorpion_S_5030_220kv_F3A_Special_Brushless_Outrunner_Motor.html. This one spins a more reasonable 8,800 rpm on 10s lipo, it is only half the power of the other one, but it has a titanium shaft

 

[Green Machine]

Here is a Scorpion motor with close to the same specs but 170kv.

That seems pretty close to an Astro?

The problem i have had with astros is they over heat too easy.

http://www.rccombo.com/en/rc-motor/2958-scorpion-sii-5525-170kv.html

 

[wildharemtbkr]

Those are tiny motors to be putting out that much power! The one you linked is down to 6300 rpm on 10s, that is actually workable! If they don't melt when they get hot they might be the ticket! Are there any that are bigger? I like the 5,500 watts of the first one, if there was a compact, strong, efficient gear reduction available. If the bike had a jack shaft that was 6 times crank speed, about 500 rpm, 40:1 would work to the jack shaft , that might be doable........ :?

 

[Green Machine]

How about this one?

http://www.scorpionsystem.com/catalog/motors/s65_series/S-6530-150KV/


150kv and rated for 3900 watts continuous.

Supposedly super efficient, and heat resistant.

Is it worth a try?

 

[Kepler]

Scorpion motors are of excellent quality. I use them in all my RC Helicopters. They can run seriously hot (like an Astro) without damage. The Scorpion motors designed for 800 class helicopters are designed for 10000W continuous and 15000W peaks.

Kv and price might be a bit of a problem though.

http://www.scorpionsystem.com/catalog/motors/hk70/HK_7050_340/

 

[fechter]

The stators are epoxy coated to prevent shorts, and are wound with wire that is rated at 180 degrees C (356 F). The magnets used in Scorpion Motors are rated for operation at 200 degrees C (392 F), making a motor that is virtually impossible to burn up in normal use."

I bet we can fry one in less than 10 minutes.

If the motor stays in the "normal use" range, it should be good. If pushed too hard, there isn't a lot of thermal mass so it could overheat very quickly. Some kind of temp sensor in the windings would be a good idea.

 

[Thud]

Green machine,
Those 55 mm motors are much smaller than the astro's your looking for alternates. The closest you will get is an 80mm motor:
http://www.leaderhobby.com/product.asp?ID=9394001224162
They seem to be on perpetual back order there.

Another (available at least) option are the 63mm motors:
http://www.leaderhobby.com/product.asp?ID=9394001224349
Again these are a step smaller than the 3" astro.

There are a couple links to other supply chains in this thread:
http://endless-sphere.com/forums/viewtopic.php?f=28&t=31019

If your cooking astro flight motor's you are running a slower wind on too low a voltage, or just overgeared for the set up.
(Or like me, your expectations are just too high listening to all the hype on the board,4kw isn't that big a kick in the pants after the initial thrill wears off)
They need to be optomised for the voltage you are running, & then geared correctly.
With cobalt magnets, the astro will withstand much more abuse than the neo shod china motors.

Chat with you soon,
T

 

[Miles]

Ref: http://endless-sphere.com/forums/viewtopic.php?f=30&t=45489