Astroflight Cobalt 40's

**mikep** · 2nd December 2005, 14:55

Anyone had any experience with these motors (with / without planetary gearbox)? Are they reliable - anyone seen the tech / performance specs for them etc.? Any gotchas?? Their website is pretty unhelpful! Am thinking of dusting off the grinder and building a mini-DisConstructor, and these motors look interesting!

**ewan** · 2nd December 2005, 16:26

Astros are brill motors if used correctly, two for a weapon would be brill (Geoff Smith will know more about that

). They are also great as drive motors with the gearsets that you can buy, (also... Geoff! well Karoline & co will also know). Problem is battery drain with so many brill motors though...

**typhoon_driver** · 2nd December 2005, 16:45

not a big fan of them. We used one in typhoon cadet in san fran. Burnt out in its first match. The resins inside the motor had melted and then the motor seized completely.

They are good motors but remember that to produce 1hp from such a small package you need a large amount of cooling because it doesnt have enough mass to do it effectively itself.

We got just as good performance from a normal drill motor (18v on 24v)

**geoff** · 2nd December 2005, 23:28

Ok, I heard someone was taking my name in vain!!

Mike,
Astroflight 40s..So were do you want to start?
I could write a dissertation on he pros and cons of this motor, we have 6 (soon to be 10) of these things spread across our feathers.
The 15:1 planetary g/box (model 940P)is a truly superb traction motor check outhttp://www.pillowtorque.com/tech.htm http://www.pillowtorque.com/tech.htm for an example of an extreme featherweight drive train. Also take a look at http://www.pillowtorque.com/pillow_fight.htmhttp://www.pillowtorque.com/pillow_fight.htm for a twin motor application using the model 40 motor without the g/box as a spinner drive.
The 940P is a very rugged drive unit but requires mounting properly using the four M4 tapped holes in the face of the gearbox and for best results the motor supported too.
The 12mm output shaft, although quite capable of having a wheel mounted directly to this shaft there is a possible issue with long term repeated shock loads weakening the front bearing. We have found that this can be avoided by using a separate axle for wheel support driven by a belt/chain from a pully/sprocket mounted on the gearbox. (see Pillow Torque) Mounted like this they are entirely reliable, we have had the same units in Pillow Torque for the better part of 2 years completing over 125 fights (mostly at 100% duty) plus many hours of testing and only now are we replacing the motor brushes and repacking the gearbox with new grease. Other than that they have had no maintenance whatsoever. As Gary points out that due to the silly amounts of power they can deliver they do produce a lot of heat, which at first seems quite worrying but we have learned that these motors are quite happy to run at 100 C all day!BUT and its a BIG BUT if you are using the motor alone as a weapons drive, then gear ratio is CRITICAL. These motors run at around 16,300RPM @ 24V We have found that a reduction ratio of a MINIMUM of 3:1 is required to prevent the heat build-up eventually melting the whole thing (ask Ewan what happens to them at 2:1!!) I would prefer a ratio of 4-4.5:1 for peace of mind.
If you want dimensions for the 940P they are herehttp://www.teamwhyachi.com/misc/A40P.pdfhttp://www.teamwhyachi.com/misc/A40P.pdfthe full spec. of the motor alone is here http://www.robotcombat.com/marketplace_astroflight.htmlhttp://www.robotcombat.com/marketplace_astroflight.html You may also want to check out these alternative gear boxes http://www.teamwhyachi.com/Twa40.htmhttp://www.teamwhyachi.com/Twa40.htm
Both Team Whyachi and Robot combat are good sources of the motors and will happily ship to the UK .

If you want any further info e-mail me teamscorpion@aol.com and Ill try to help.

Regards,
Geoff.