48" EPP Yak

[SWAMPER]

Strange problem
Got the Yak all done and running the Omega 130g 870kV motor and a hurk 50amp esc from heads up RC with built in bec and a 3s 2200 lipo, and the strange part is as I give it throttle the motor chugs wants to start backwards then it will kick in and go forward, and when I have it full throttle the control surfaces will flutter sometimes ?
I have run these esc a bunch and never a problem but sounds like it may be bad, I have never seen a motor try to start up backwards kind of like the esc is having a hard time figuring out the motor phase

 

[gyro]

I agree with all your observations. One thing you can do to solve the phase problem is to have the throttle on a kill switch, and bump up the throttle trim do that the motor is always spinning unless the throttle is cut.
Not sure what the flutter is from, maybe the built in BEC is getting too hot?

 

[njswede]

I've had the same problem occasionally with some motor/ESC combinations. The standard answer is to experiment with the timing.

Another thing I had happen to me was that the shaft was rubbing slightly against some wood. When the motor spun up, the ESC must have been confused when it felt resistance that wasn't supposed to be there and it started sputtering. Making sure the prop spun freely solved the problem.

 

[MattInFla]

For those who have flown both, how does theYak fly compared to the 47" extra or the 48" 540 (1.5 buck huck)?

Matt

 

[SWAMPER]

still having crazy problem with getting the motor and esc to work right, i sent the esc back and they checked it out and tested it and it's fine, so i'm thinking the Omega motor may be the problem any one else have a problem with these motors ? it still wants to try and start up backwards at times and just flat out act strange ? i may have to just get another motor i'm trying to get a hold of 3DH and see if they have a known problem with the motors

 

[SteveT.]

still having crazy problem with getting the motor and esc to work right, i sent the esc back and they checked it out and tested it and it's fine, so i'm thinking the Omega motor may be the problem any one else have a problem with these motors ? it still wants to try and start up backwards at times and just flat out act strange ? i may have to just get another motor i'm trying to get a hold of 3DH and see if they have a known problem with the motors

What ESC? if it is a Hacker, they are known to have this "issue" , though it is normally no big deal. Even the guys at Aero-model admit this. If it is a Castle, then you might need to change the acceleration settings to a higher setting.

Basically, what is happening, is that since these motors don't have brushes and a commutator, the ESC take the place of them, and when you give it power, it takes a split second to for the pulses that run the motor to get it turning the right way...

SteveT

 

[Steve_B]

What ESC? if it is a Hacker, they are known to have this "issue" , though it is normally no big deal.

+1.. I've experienced this myself on Hacker and Extreme Flight ESC's (both possibly made in same factory?). Caused by inability of the sensorless ESC to work out the position of the rotor at start up.
I'd debate the point about it not being a big deal.. I found it a real pain in the neck standing there for what seemed like an eternity trying to get a motor to spin up. It also caused me a few dead stick landings and near misses when the motor wouldn't spool up in flight. I ended up migrating to the much cheaper ZTW ESC which doesn't have this problem and is equally good in all other respects.

Some program in an idle to work around the spooling up in flight issue but that still doesn't help with the 'cold start'.

Here's what mine looked and sounded like:
[video=youtube;_immMpBlsRs]http://www.youtube.com/watch?v=_immMpBlsRs[/video]

 

[SteveT.]

Ok....I'll re-phrase....it has never been a big deal for me....but then the only plane that I have a Hacker ESC in is a Great Planes "Electrostick" which I don't even try to do 3D with....

SteveT

 

[SWAMPER]

it's a hurk esc from heads up rc i have used a bunch of these esc's and never had an issue before, i guess the omega motor is more the problem seems like it doesn't like this esc much , i just don't want to cut the throttle in the air and then get back on the throttle just to have the motor not kick in till it figures it's self out ??

 

[gyro]

it's a hurk esc from heads up rc i have used a bunch of these esc's and never had an issue before, i guess the omega motor is more the problem seems like it doesn't like this esc much , i just don't want to cut the throttle in the air and then get back on the throttle just to have the motor not kick in till it figures it's self out ??

The hurk ESC is a "budget" ESC if remember, while I'd say the Omega is a "premium" motor with thousands sold I'm guessing.
I'd recommend getting a better ESC and then see if you still have problems... My guess is you won't.
Sorry if it comes across wrong, just trying to boil things down to the bottom line.

-G