100% scale, Electric Lazair - Page 3 - RC Groups
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Mar 27, 2011, 09:40 PM
Dale Kramer
KiloOne's Avatar
I just ordered some 680 uf 75v low ESR Mallory capacitors. I will use four of these to replace the three 820 uf 63v ZL series Rubycon capacitors that were on the Spin 300. Not only were the Spin 300 caps crazy glued together, they were crazy glued to a pcb. I am committed now.

Throttle quadrant and one battery pack are done now.

Last edited by KiloOne; Mar 28, 2011 at 10:01 AM.
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Mar 28, 2011, 03:30 PM
Nelapaty's Avatar
now that's a lot of packs is that 16 packs on one PCB board? reread the first post 16s4p wow that's some juice...
Mar 28, 2011, 04:47 PM
Fltofancy's Avatar

How much so far?

Hi Dale,
How much do you have invested in this setup? I was looking at putting electrics on the Mark 4 with the Yunique system but it was looking like about 12k for motors, batteries and controllers.

Mar 28, 2011, 07:14 PM
Dale Kramer
KiloOne's Avatar
Hi Gene,

I will have a little over $8,000 in this project without the 8 kw generator which will cost about $1,400.

For comparison you should note that I will have about 7 kwhr of batteries on board and have chargers with a total charging capacity rated at well over 7 kw.

Last edited by KiloOne; Mar 28, 2011 at 10:52 PM.
Mar 28, 2011, 10:42 PM
Fltofancy's Avatar
Thanks Dale.
Many folks have expressed an interest in an electrified Lazair but want it at the same price as fossil fueled units. Any idea on where your going to be w/r/t 254 lbs limit?


By the by: looks like I might have a facility to start new production in the next couple of months.
Mar 28, 2011, 10:49 PM
Dale Kramer
KiloOne's Avatar

Thats good news.

I'll weigh in at 254 + 5 gal of gas or about 285 lbs.

Did you get the email I sent you at 7:10 pm tonight?

Last edited by KiloOne; Mar 29, 2011 at 04:22 PM.
Mar 28, 2011, 10:58 PM
Fltofancy's Avatar
No I didnt receive an email. Try Fltofancy@gmail.com.

Mar 29, 2011, 07:09 PM
Fltofancy's Avatar
Will the bureaucrats give you the 5 gal of gas weight allowance? I'm not familiar with how FAA regulates electricified part 103 vehicles.

Mar 29, 2011, 07:18 PM
Dale Kramer
KiloOne's Avatar
Time will tell. I believe there are more arguments for than against. I will be a much smaller threat to people on the ground if I crash than an ultralight with 5 gal of gas in it.
Apr 17, 2011, 06:23 PM
Registered User
I will buy your JPX engines if you are done with them Have you thought about APRS for your trip as well? I think I would like to intercept you on your trip this summer and form up perhaps, that would be pretty neat.
Apr 18, 2011, 08:11 AM
Registered User


Awsome mate I intend on completing tie same conversion as soon a a find a suitable Lazair to purchase.

Originally Posted by KiloOne
Over 30 years ago I designed the Lazair ultralight. My company 'Ultraflight' produced about 1200 of these aircraft kits between 1979 and 1985. I believe that, over the years, there have been Lazairs in 5 museums, including one in the Smithsonian right now.

Back then, there was a revolution of sorts when we married modern lightweight 2 cycle engines with lightweight airframes and ultralights were born.

Today, another revolution is possible. The RC model aircraft industry is propelling this revolution with the batteries, chargers and power systems we see today.

The twin engine Lazair is an ideal vehicle for electric conversion and over that last 10 years I have dabbled in trying to electrify one several times. Each time I was thwarted by many issues but this time I will do it. There has been an electric Lazair flying in England for a couple years using Predator motors.

Experience has shown me that the Lazair can fly around at about 30 mph using only about 3 kw of power.

The RCgroups forums have been invaluable to me in obtaining knowledge that I need to build this unique version of the Lazair.

Rather than hijack other threads I have been following, I have started my own Build Log here, in 'Batteries and Chargers', the heart of the enabling hardware that will make his happen. I am sure that 'Power Systems' will get their fair share of crossover reader interest.

I don't want to consume too much of my time posting and monitoring this thread but in a way I owe it to you guys to give some hard earned knowledge back to the ether.

Here is what I have chosen so far:

Two 10 kw Turnigy CA120-70 motors with 32-10 props reconfigured to WYE terminations.

Two JetiSpin OPTO 300 controllers.

96 pieces of Zippy 5000 mah cells arranged in 6 packs of 16s4p each.

Six of FMAdirect PL8 v2 chargers, each one running off two 12v 900 watt Dell Poweredge 6650 power supplies wired in series to get 1800w at 24v.

Testing so far shows that I can expect to have close to 2 hours endurance with this 'legal' ultralight setup and then be able to recharge the batteries in about 1 hr.

I have attached a few pictures to this post and will add pictures as new posts as I can. Although I do expect to fly the Electric Lazair on this float setup, the first flights will be on wheels.

And by the way, my current plans are to fly this airplane from my home in Hammondsport, NY to the Atlantic ocean, to the Pacific ocean, to Oshkosh and then back home this summer.
Apr 18, 2011, 06:32 PM
Dale Kramer
KiloOne's Avatar

I'll be setting up a website and at least have a link where people can see where I am and my latest projected path. My Iphone will be reporting my position regularly.

I will be taking a very southerly route across the US, so it would be quite an intercept from Edmonton.

[EDIT] Unless you want to meet up at Oshkosh on my way back!

I will not make a decision on what to do with my JPX's for a while since I have another Elite that has not flown yet and needs engines. I will keep you in mind.


Thanks, I'm sure the used Lazair market will get a boost when the electric Lazair proves practical.

Last edited by KiloOne; Apr 19, 2011 at 10:07 PM.
Apr 18, 2011, 07:47 PM
Dale Kramer
KiloOne's Avatar


I am sorry for not posting my progress lately.

I have had a 2 week setback caused by an error I made rewiring one of my motors to WYE configuration. One of the drawbacks of working on this alone, no-one to double check things.

I'm now full steam ahead again.

But from where I left you last, I decided to bench-test the power system on a stand and I just picked up at random one of the two motors to test. Unfortunately the motor I picked up was one that I had not terminated to WYE correctly. I connected the wrong three wires together to make the center node. I connected two phase starts and one phase end instead of three starts. The motor ran but was running hot and a little 'noisy'. Since I had nothing to compare it to I just kept increasing power over a few sessions until I was up to about 8 kw and probably wide open throttle. It was only a few seconds at this power when a battery lead connection literally blew apart and stopped the test. Upon further investigation I found that I had blown 24 of the 30, 75 volt output FETs in the $650 SPIN 300 motor controller. And further, the 'brain' PCB in the controller could not be coaxed back to life. Total controller loss!

The motor was hot but appeared unharmed. At this point I was worried that I had caused the failure due to my 16s battery voltage which I know is over the recommended voltage for the controller.

I rewired my battery packs down to 12s for the next test with the second and only remaining controller I have. I started running the first motor at 3 kw and a couple minutes into the run the motor fried with a burning smell and one stator winding was black. Fortunately the second controller was still OK.

Now I am thinking that the motor windings were shorted between phases at high power levels leading to a complete short eventually at lower power. Things were not looking very good here for a few days.

Eventually I decided to run the second motor with the second controller to see if it behaved better and did not have a winding short. Right away I knew that things were looking up. This motor was very quiet and ran very cool. I was only able to get 6 kw or so on the 12s voltage so I went back to 16s and was able to get 7.5 kw out of it at WOT and it remained below 140 degF. Now I was very happy and was investigating rewinding the first motor myself when I had the realization that I had not terminated the first motor correctly. It was all my fault, not the motor windings.

I spent a few days researching the rewind that I had to do on the first motor and decided to wind it with 30 strands of 23 awg magnet wire instead of the 173 strands of Metric 2.0 magnet wire it was originally wound with. This allowed me to get about 40% more copper in the windings with the same number of turns. My rewound Motor#1 performs perfectly, giving me 10,400 watts (about 13 hp) at 5,200 rpm on my 32x12 props with a fresh battery charge. I have just over 70 lbs of static thrust which should give me nice performance at my now well over 200 pounds of body weight. Also, it appears that I will not have an engine overheating concern at high power levels.

I am now spending my time building up the remaining battery packs, chargers and getting ready to rewind the second motor to match my successfully rewound Motor#1.

I will try to catch up with pics as I can.

Back to work now,
Last edited by KiloOne; Apr 19, 2011 at 03:06 PM.
Apr 19, 2011, 08:22 PM
Dale Kramer
KiloOne's Avatar

Burned out motor

A real low point!
Apr 19, 2011, 08:24 PM
Dale Kramer
KiloOne's Avatar

Winding test

A test wind to see if I can really get that much extra copper into the motor before I order the 23 AWG magnet wire.

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