HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Jan 31, 2013, 05:23 PM
3DHOG
jcdfrd's Avatar
USA, CA, Aromas
Joined Sep 2010
4,848 Posts
Quote:
Originally Posted by PeterVRC View Post
There is no play in the bearings still. So I guess it all came from shaft flex.
You could also throw in the possible X amount of blade flex/stretch, which would reduce the distance that any shaft flex needed to do to bridge the gap to the housing wall.
All those factors would escalate into a worse case as it unfolded too.

The nuisance part is that it was looking to be a useful cheap motor. But now it is a worry seeing the exact starting cause is not known. eg did a prior run damage it, via post soak heat. As 60degC seen externally would be X amount higher internally.
Or some other reason....

Oh well.... onwards to some other motor now....
motor is not up to the task at hand
jcdfrd is offline Find More Posts by jcdfrd
Reply With Quote
Sign up now
to remove ads between posts
Old Jan 31, 2013, 05:54 PM
EDF rules... :)
AirX's Avatar
Joined Nov 1999
13,583 Posts
Quote:
Originally Posted by jcdfrd View Post
well rotors dont really expand, what is happening is due to an out of balance the rotor will wobble and thus the fsa expands but not the rotor. the rotor is just not spinning true and is due to a less than exceptable assembly and balance. more clearance is not needed a better assembly and balance is
Some rotors can, plastic is elastic and can stretch and return back to a high degree of original shape. Depending on the substrate and reinforcing material there can be a small amount or a lot of stretch.
The rotors made of metal will not exhibit the same elastic properties unless there are other forces acting on it like heat or pressure. Carbon fibre will fail at more or less a specific point similar to metals.

Centrifugal forces are powerful as you can see in a rotor pushed to destruction.

Eric B.
AirX is offline Find More Posts by AirX
Reply With Quote
Old Jan 31, 2013, 05:55 PM
Registered User
Australia, VIC, Melbourne
Joined Nov 2006
10,877 Posts
Yeah, I would never buy a 2850 normally.... but it was low KV (2060kv) and cheap, thus worth testing to see what power level it would run at.
65A area should have been fine for it. Mainly running 58A area (1.75Kg Thrust area) after coming down off peak.
But I guess it didn't like something about the situation! hehe

Those Thrust/power numbers are pretty much exactly what I want for a use..... so I will have to go and find some other 2000kv to 2050kv area motor. Inrunner..... more towards 2860 size, so it has leeway to cope assured.
PeterVRC is online now Find More Posts by PeterVRC
RCG Plus Member
Old Jan 31, 2013, 07:11 PM
Registered User
SKYRYDER1000's Avatar
NEW JERSEY U.S.A.
Joined Mar 2010
494 Posts
Does anyone have bench numbers on a cs 10 and a HET 2W-23 2950kv??

Thanks!
SKYRYDER1000 is offline Find More Posts by SKYRYDER1000
Reply With Quote
Old Jan 31, 2013, 07:37 PM
speedin n da weeds :)
sikky's Avatar
USA, AZ, Glendale
Joined Feb 2008
595 Posts
Don't forget about the blades pulling forward, also that and the stretch at the base will cause it to deflower or Peel the rotor blades up and out.
sikky is offline Find More Posts by sikky
Reply With Quote
Old Jan 31, 2013, 08:53 PM
chuck
santa barbara, CA
Joined May 2009
4,109 Posts
what size shaft? i have had a 3.17 do the same.
chas650r is online now Find More Posts by chas650r
Reply With Quote
Old Jan 31, 2013, 09:27 PM
Registered User
Australia, VIC, Melbourne
Joined Nov 2006
10,877 Posts
4mm shaft

Oh yes, for sure 3.17mm are WEAK. I have had one of those bend a shaft when I forgot to balance the CS10 rotor first!

But that is a bit different failure process.
The motor shaft ends up bent for a start (this 4mm is not) and this bend means the rotor jams and can't even come out of the housing anyway.
But you still get noises and motor smoke, LOL.
PeterVRC is online now Find More Posts by PeterVRC
RCG Plus Member
Old Jan 31, 2013, 09:37 PM
Registered User
WhalleyB0Y's Avatar
Canada, BC, Surrey
Joined Jul 2011
893 Posts
Quote:
Originally Posted by SKYRYDER1000 View Post
Does anyone have bench numbers on a cs 10 and a HET 2W-23 2950kv??

Thanks!
I am waiting on a pair of these to arrive in the mail. I will be testing them in CS12's for use on 4s and 5s. If they work out I will use them in my Projet A10. It's likely that I would post my results in the CS12 forum.
If anyone else has numbers on this setup I would also like to see them.
WhalleyB0Y is offline Find More Posts by WhalleyB0Y
Reply With Quote
Old Feb 01, 2013, 04:44 PM
Extreme CNC Alloy EDF
Extreme_RC's Avatar
Australia
Joined Mar 2006
11,528 Posts
2W23 is a little light on for really good efficiency in the CS10, pulls more amps than the 2W25 for very little difference in RPM.
Extreme_RC is offline Find More Posts by Extreme_RC
Reply With Quote
Old Feb 01, 2013, 05:36 PM
EDF rules... :)
AirX's Avatar
Joined Nov 1999
13,583 Posts
Quote:
Originally Posted by sikky View Post
Don't forget about the blades pulling forward, also that and the stretch at the base will cause it to deflower or Peel the rotor blades up and out.
+1

Eric B.
AirX is offline Find More Posts by AirX
Reply With Quote
Old Feb 01, 2013, 07:00 PM
Registered User
WhalleyB0Y's Avatar
Canada, BC, Surrey
Joined Jul 2011
893 Posts
Quote:
Originally Posted by Extreme_RC View Post
2W23 is a little light on for really good efficiency in the CS10, pulls more amps than the 2W25 for very little difference in RPM.
Yea in hindsight, I would have preferred the 4mm shaft of the 2w-25 but I really don't mind the amps a little higher.
WhalleyB0Y is offline Find More Posts by WhalleyB0Y
Reply With Quote
Old Feb 03, 2013, 06:24 AM
Registered User
Joined Jun 2007
76 Posts
Hello Guys!

I purchased a L-2855-2800Kv motor and a 10 blade 70mm changesun fan.

I am using a brand new 4cell turnigy nanotech 4000mah and a HobbyWing Pro 80-a Esc.

Hooked up the set up, set the max-min throttle points and ran up the fan.

I managed to get 700g of thrust, on the following specs:

Voltage: 16.7v
Amps : 46a- 48a


i've read the people managed to pull 1kg thrust and 63 amps on this motor on the same fan.

i;m wondering how, anyone got any insights? did i do something wrong?
T-BONEZ is offline Find More Posts by T-BONEZ
Reply With Quote
Old Feb 03, 2013, 06:28 AM
Registered User
Australia, VIC, Melbourne
Joined Nov 2006
10,877 Posts
Was that on the bench, or in a plane?
If it was in a plane then it is likely it is not getting enough airflow - in and/or out.
On the bench..... 56A to 62A sort of range (battery dependant - higher end for yours) and 1.4Kg to 1.5Kg thrust area.
PeterVRC is online now Find More Posts by PeterVRC
RCG Plus Member
Old Feb 03, 2013, 06:34 AM
Registered User
4stripes's Avatar
Canada, ON, Burlington
Joined Jan 2009
2,937 Posts
Are you using an inlet lip?
4stripes is offline Find More Posts by 4stripes
RCG Plus Member
Latest blog entry: Some photos of the EDF fleet!
Reply With Quote
Old Feb 03, 2013, 06:34 AM
Registered User
Joined Jun 2007
76 Posts
that's the werid part, it was on bench, battery fully charged....
no in-take lip...

could it be the dudes at hk labeled the wrong motor and mailed me the wrong product?
T-BONEZ is offline Find More Posts by T-BONEZ
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
New Product Change Sun 12 blade 90mm Flip Flop Electric Ducted Fan Jet Talk 7081 Jul 28, 2014 08:25 AM
New Product Change Sun 120mm and new 10 blade 70mm fans Flip Flop Electric Ducted Fan Jet Talk 131 Apr 27, 2012 07:07 PM
Sold Change Sun electric retracts Flip Flop Aircraft - Electric - Jets (FS/W) 3 May 23, 2011 06:20 AM
Sold Change Sun Electronic retracts w/Lander struts hole digger Aircraft - Electric - Jets (FS/W) 2 May 06, 2011 01:27 PM
Sold Change Sun Electric retracts NIB 75.00 jzuniga Aircraft - Electric - Jets (FS/W) 2 Sep 03, 2010 09:36 AM