HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Jul 05, 2004, 08:26 PM
Registered User
Madison, WI
Joined Oct 2003
661 Posts
AXI 2820/10 - is it on it's way out?

I finished a long flight with my Hoot this morning, and maybe went a little too long on a few climbs. I use the AXI 2820/10 outrunner and 10 x GP3300 cells with a 12 x 8 prop. I use the smaller prop so as not to pull too many amps for this motor. Even this settup can pull as much as 50 amps on a fresh warm pack and indeed it was a fresh warm pack I was using. Everything went well climbing, thermalling, a bit of zooming and what little aerobatics I'm capable of. When I went to change the battery it was fairly hot, and so was the motor. I moved the prop out of the way and noticed it had a lot of resistance - much more than I have ever noticed before! It felt like the kind of compression you feel with a glo type engine when you turn it. I always felt this in the past, but not to this extent. Anyway, I checked it out on the bench later. It felt the same, but amp draw looks normal and the motor seems to pull ok. Is this just a warning that something is about to give? Should I be pricing motors?
hbielich is offline Find More Posts by hbielich
Reply With Quote
Sign up now
to remove ads between posts
Old Jul 06, 2004, 08:24 PM
Registered User
Madison, WI
Joined Oct 2003
661 Posts
I guess the answer was obvious to everyone else...

Since I received no replys, I will respond to my own question:

Don't risk it! If it doesnt feel right, it must not be right. You are asking for trouble if you continue to fly with this motor!
hbielich is offline Find More Posts by hbielich
Reply With Quote
Old Jul 06, 2004, 08:24 PM
Registered User
Madison, WI
Joined Oct 2003
661 Posts
You should have used a smaller prop! Then you wouldn't have drawn so many amps.
hbielich is offline Find More Posts by hbielich
Reply With Quote
Old Jul 06, 2004, 08:26 PM
Registered User
Madison, WI
Joined Oct 2003
661 Posts
OK - OK...
I just ordered a 2820/12 instead of the 2810/10. Maybe it can handle the load better. And I promise to be gentle on the motor - at first anyway.
hbielich is offline Find More Posts by hbielich
Reply With Quote
Old Jul 06, 2004, 08:32 PM
Average User
M Ashmore's Avatar
Bakersfield, California
Joined Aug 2003
1,726 Posts
That's a hoot, hbielich.

Hey, toss that old used up 2820/10 my way. I've been know to take few risks.
M Ashmore is offline Find More Posts by M Ashmore
Reply With Quote
Old Jul 06, 2004, 10:37 PM
Registered User
Hastings, Hawkes Bay, New Zealand (Aotearoa)
Joined Feb 2000
1,453 Posts
Often after running a brushless motor there is still a charge from the capacitors on the controller applied to the motor. This has the effect of a brake, see if the problem goes away if you disconnect the controller from the motor.

Heather
Heather is offline Find More Posts by Heather
Reply With Quote
Old Jul 06, 2004, 11:10 PM
Registered User
Madison, WI
Joined Oct 2003
661 Posts
No. The motor feels the same with nothing connected to it. I thought maybe the bearings went bad, but I would have expected a grinding feel to it. Instead it feels like the magnets have become extra strong and resistance, like strong opposing magnets, is felt as each magnet is passed when the rotor is turned.
hbielich is offline Find More Posts by hbielich
Reply With Quote
Old Jul 06, 2004, 11:38 PM
Registered User
Joined Aug 2003
127 Posts
A 12x8 with 10 GP3300's sounds a might hefty the biggest prop I use is 11x5.5. and currently fly my Hawes Tucano with 10x7 APC e. The Axi 2820/10 if run over 40amps for an extended period tends to get hot resulting in loose magnets (in the older ones I am told) causeing a coggy feeling to the motor, have you opened it up to see if this is the case?? If you dont want the motor toss it my way, I am sure as long as it has not ground the windings to dust it is repairable. Several of the guys I fly with have nosed the birds in and have had magnets break free sticking them back with a good epoxy seems to work, hope this helps.
Toeknee is offline Find More Posts by Toeknee
Reply With Quote
Old Jul 07, 2004, 04:34 AM
Registered User
Madison, WI
Joined Oct 2003
661 Posts
Thanks. I'll open it up and see if any magnets have broken free. I'm surprised that it can still run like that though.
hbielich is offline Find More Posts by hbielich
Reply With Quote
Old Jul 07, 2004, 12:00 PM
Registered User
Singapore
Joined Jul 2003
643 Posts
hbielich,

Maybe a little late but have you considered the Pletti Orbit 15-14 or 15-16? Much better build and can take your current setup with no sweat. ICare lists theirs at $139, which IMHO, is worth the extra over a 2820.

Rgds.
Vic Peh is offline Find More Posts by Vic Peh
Reply With Quote
Old Jul 07, 2004, 08:49 PM
Registered User
Charleston, SC
Joined Jul 2001
85 Posts
I've had two of these motors with loose magnets within the last few weeks. It appears that if they are pushed to around 40 amps for even a short period of time, the glue starts to let go of the magnets. On both of mine, just a few magnets had moved forward and were being ground off as the motor ran. I probably flew a whole flight that way. Noticed a lot of heat and smell after landing. Hobby Lobby swapped one out for 1/2 price and recomended I use a smaller prop. However, I may not be satisfied with power. Will see after it arrives. If I loose another, I will look for an alternative.

Gary
garymac is offline Find More Posts by garymac
Reply With Quote
Old Jul 07, 2004, 11:42 PM
Registered User
Madison, WI
Joined Oct 2003
661 Posts
Yup! I opened it up and sure enough, 2 magnets were loose. I will try to epoxy them back with 30 minute epoxy, but don't know if this is the right stuff to use. I ordered the 2820/12 with the hopes that it can handle a few more amps and I will use a smaller prop. I don't need the speed for this plane anyway since it is only for practice for a Lea V with a Hacker FAI carbon motor.
hbielich is offline Find More Posts by hbielich
Reply With Quote
Old Jul 08, 2004, 12:17 AM
Registered User
Joined Aug 2003
127 Posts
Quote:
Originally Posted by hbielich
Yup! I opened it up and sure enough, 2 magnets were loose. I will try to epoxy them back with 30 minute epoxy, but don't know if this is the right stuff to use. I ordered the 2820/12 with the hopes that it can handle a few more amps and I will use a smaller prop. I don't need the speed for this plane anyway since it is only for practice for a Lea V with a Hacker FAI carbon motor.
hbielich the 2820/12 should handle quite a few more amps, with the same setup you will still be pulling around 40amps static with the lower kv of the 2820/12.
www.flydma.com has a calculator you can use to get some idea of your amp draw, it has a large selection of motors, batterys and props for a guide, and it is only that, a guide, the only sure way is to check your setup with a meter such as the VA Tester from Cermark or the watts voltmeter from Astro flight.

If the little extra cost is not a concern the Orbit from Plettenburg is a good alternative or any motor that has a high volt/amp rating, I am considering the Himax 3630/1000 to replace the 2820/10 in my next project it has a Kv of 1000 and only $85 from Esprit, the down side is it is about 3oz heavier than the Axi.

Let us know how it all works out.
Toeknee is offline Find More Posts by Toeknee
Last edited by Toeknee; Jul 08, 2004 at 12:20 AM.
Reply With Quote
Old Jul 08, 2004, 08:12 AM
Registered User
Austin, TX, USA
Joined Feb 2001
415 Posts
According to the model motors website the 2820/12 has a lower max current 35A vs 40A) than the /10, which is expected for a lower kv motor.
Bob Baker is offline Find More Posts by Bob Baker
Reply With Quote
Old Jul 08, 2004, 08:40 AM
Formerly of mcba fame
Matthew Allen's Avatar
Luxembourg
Joined Apr 2001
3,007 Posts
Because of the various stories I've heard, much like this one, I ordered a Himax 3630/1000 for the Tucano I'm building.

You might consider this alternative - it's only $85 from Espritmodel.com, and though it's heavier, it's supposed to be excellent.

Matthew
Matthew Allen is offline Find More Posts by Matthew Allen
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
For Sale Ripmax spitfire Axi 2820/10 HS81's 109Mechanik Aircraft - Electric - Airplanes (FS/W) 0 Jul 31, 2007 10:11 AM
Question Is Ultrafly on it's way out booger Vendor Talk 6 Mar 24, 2007 02:23 PM
Discussion AXI 2820/10 on Large Wing FlyingW Flying Wings 8 Aug 10, 2006 02:33 PM
Discussion AXI 2820/10 burn out on 3s Lipos leccyflyer Power Systems 10 Jul 24, 2006 08:34 AM
axi 2820/10 on 12 cells? Janusz Jawien Power Systems 1 May 06, 2003 09:50 PM