100% scale, Electric Lazair - Page 8 - RC Groups
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Jun 01, 2011, 08:51 AM
Dale Kramer
KiloOne's Avatar

No static wicks, I have a lot of hours in sailplanes with very sensitive computers and instruments on board and static buildup has never been a concern.


Nope, have never seen Airy-plane.
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Jun 01, 2011, 09:54 AM
Dale Kramer
KiloOne's Avatar

Flight test report #1

On Sunday May 29th I flew the electric Lazair for a total of about 38 minutes of air time and about 7 minutes of pre flight taxi testing and test hops. There were 4 flights of circuit length or longer. After the testing I charged the batteries and determined that I had used 75% of their capacity during the testing.

Much of the time was spent at very high throttle settings.

Unfortunately, the display I have chosen for viewing of electric system parameters has proven unreliable so far in the field. Only one engine display seemed to be providing usable information most of the time (not all of the time). This contributed to the fact that I overheated both motors sometime in the flight testing. At the end of the last flight, the motors were still performing reasonably well but during most of the actual flying I was battling with what appeared to be an overheating problem at high power levels. In addition, both of the log files of the testing had little usable information in them.

Upon inspection after the last flight, I noticed what appeared to be solder spray that had landed on some stator windings of both motors. After disassembling both motors I found that the Y node of the WYE wound motor windings had overheated and the solder from the node had melted and migrated out, onto the windings. Although the node was still mechanically sound because I had wrapped the joint with fine stands of wire while I was soldering it, the overheated joint was a likely source of additional heating. I was lucky that the joint did not completely fail and destroy my motor controller again.

In hindsight I should not have buried this soldered Y node deep inside the motor windings, the hottest section of the motor. Currently I am beginning the rewinding process on both motors again but this significant delay in testing has forced me to cancel my cross country plans. I still hope to be able to fly the plane at Oshkosh.

Needless to say, I will terminate all 6 of the winding ends outside the stator area this time.

Here are some pictures:
Last edited by KiloOne; Jun 01, 2011 at 11:06 AM.
Jun 01, 2011, 10:57 AM
Registered User
simply awesome!!!
Jun 01, 2011, 11:21 AM
Registered User

Congratulations Dale!!!

Very happy to hear that you had a safe Maiden! Keep up the good work!


ps: I have one of these motors on the way from HK for a 35% Extra 260! I think it should handle my 30# plane!
Jun 01, 2011, 11:48 AM
Registered User
Congratulations on the test flights. To bad about the motors getting cooked.

Is that an eagletree sensor you are using for power data? I wonder if you are getting unusual results because the sensor is resting directly over another power lead.
Jun 01, 2011, 12:29 PM
oh man how coool is that it fly :-):-)
Jun 01, 2011, 05:27 PM
Nelapaty's Avatar
Jun 01, 2011, 07:05 PM
UAV Integrations
AWESOME! That is so cool that it is up and flying (even with setbacks). Keep us updated!
Jun 01, 2011, 08:21 PM
3D, 1D at a time!
Park_aviator's Avatar
That, my friend, takes skill... Amazing! :d
Jun 01, 2011, 08:22 PM
3D, 1D at a time!
Park_aviator's Avatar
Skill, and a lot more guts than I have
Jun 01, 2011, 08:42 PM
Registered User
Congratulations on your first flight. The fact that you accomplished this milestone with relatively inexpensive RC components is amazing. BTW, did you upgrade the bearings in the motors when you did the rewind, or are they stock? Perhaps some of the excess heat is coming from poor quality bearings. The Turnigy C80100 motors have a reputation for sub-par bearings.
Jun 01, 2011, 08:52 PM
Dale Kramer
KiloOne's Avatar
Thanks everyone!


Good observation, my first thoughts were similar to yours but I figured that this logger was made to be in proximity to power wires. Also, the power panel display was not registering even with no motor running. I will still investigate this further as a potential reason that the logged data was corrupt, but still with no motor running the logged data was bad.


All the bearings in this motor appear to be good quality, the large bearing is a Japanese NSK and the 4 small bearings are Thailand NMB. They are definitely precision bearings. I think HK does try to respond to quality issues over time.
Jun 01, 2011, 10:51 PM
Registered User
Dale, just read up on re-winding motors. Do you think it is necessary to rewind these motors. I understand what you are trying to do withe wye term.

Also, I known that the Lazair is your creation, but are there any other UL craft you would consider electrifying (looking for suggestions). I too would want a twin but the only other twins I have found were the Hummingbird and Kolb Flyer (pusher).

I also have been considering stacking the motors in a contra rotating fashion on a single engine UL, ever given that any thought?

Jun 02, 2011, 12:41 AM
Registered User

Joby Motors

They have a nice motor that would work well with this project.

Jun 02, 2011, 08:12 AM
Dale Kramer
KiloOne's Avatar
Originally Posted by redgreen
They have a nice motor that would work well with this project.


I came across these motors about a month ago but didn't want to commit to another motor at that time. Now is the perfect time to switch over. I believe that the inrunner design of the Joby motor and larger diameter will help provide the solution to my stator cooling problems for long periods of high power use.

I have just ordered two JM1S 70 motors. There was 1 in stock so I hope to receive it soon and the next will take 2 to 6 weeks (I am hoping for 2 weeks).
I also have two sets of wood props (34x20s and 36x20s) from my Lazair development days that should be a good starting point for these motors.

Thanks for posting, I am very excited about these motors.


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