100% scale, Electric Lazair - Page 41 - RC Groups
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Aug 20, 2012, 02:22 PM
Pickin' an a Flyin'
Wufnu's Avatar
Originally Posted by Gedexas
I imagine that the weight of a solar panel requires more energy to move itself though the air than it generates, especially when the platform like Lazair is not optimal in the glide ratio department. What does Lazair glide? 20:1 on a good day?

There is one aircraft that can propell itself indefinitely by it's own on-board solar panels. I believe NASA debuted this aircraft a few years ago. It's far from being able to carry any significant load, though. To be fair, it's far from looking sturdy enough to withstand a serious gust of wind.
You mean Helios? Designed by Aerovironment, a company I so badly wish to work for.

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Aug 20, 2012, 05:01 PM
Registered User
Fourdan's Avatar
Hello Gianni

What price + shipping to Italy you got from CA120-80 GS Models ?

Aug 20, 2012, 05:18 PM
Hello Louis ,

I am waiting replay from my Chinese colleagues about costs .

I am also checking information on the WEB for re wire this motor

( like powercrocco.de made for the terminator 30-9 )

unfortunately no information ,.

You never see on web re wire the CA 120-70 ?

Aug 20, 2012, 10:27 PM
CP heli ≠ 3D heli
Gedexas's Avatar
Originally Posted by Wufnu
You mean Helios? Designed by Aerovironment, a company I so badly wish to work for.

Yes, that's the one I had in mind. I thought it was designed as some sort of airborne meteorology station or some other probe function, maybe even a communications device, as it seems that this aircraft is impractical for transportation of pretty much anything else.

And this is what it looks like after a gust of wind gets it:

Aug 20, 2012, 11:48 PM
Pickin' an a Flyin'
Wufnu's Avatar
Yah, horrible but it happens. Failure breeds progress.
Aug 21, 2012, 08:58 AM
Registered User
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 32-12 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 (turned out to be 1 hr 20 min, so much for tests) with this 'legal' ultralight setup and then be able to recharge the batteries in about 1 hr (turned out to be 1 hr 15 min, not too bad a guess).

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.
Wow ! remember the Christmas story kid ? " You'll shoot your eye out kid !" Well your gonna kill yourself man ! Be careful
Aug 21, 2012, 01:53 PM
Hello ,

Chinese manufacturer of the motor CA-120-80 ( 200cc )


is working in a more powerfull motor
a.s.a.p. I will keep you informed

Aug 23, 2012, 07:48 AM
Hello ,

I leave this forum and open one dedicated to the
retrofitting of ultralight electric glider, the name is:

Building an electric ultralight glider

thanks to all

Aug 23, 2012, 04:59 PM
Registered User
Aviefly's Avatar
Here is a link to it for anyone interested
Sep 08, 2012, 02:17 PM
homo ludens modellisticus
Ron van Sommeren's Avatar
Lehner Torqstar and SLS - controller
-> Solar Speedboat FuriaOne

The other (solarrace) videos on the SLS-page are in Dutch and Frysian language (I can understand about half of Frysian it seems).

See also

Testing with air-prop, instead of boat-prop
SinusLeistungsSteller mit TORQSTAR3 von Lehner (1 min 1 sec)
Last edited by Ron van Sommeren; Sep 08, 2012 at 02:53 PM.
Sep 11, 2012, 10:33 PM
Registered User
Wow ! remember the Christmas story kid ? " You'll shoot your eye out kid !" Well your gonna kill yourself man ! Be careful

Please try to control your responses.
Let Dale do what he needs to do. Any one of us can
die for any number of dumb ass reasons (believe me I know). There is a nobility
in his effort that transends the overworrying musings of the common
man. I know you have his best interests in your heart, just keep your darkest fears
to your self,Please.
Don Parsons
Last edited by dpyakker; Sep 11, 2012 at 11:04 PM. Reason: incomplete
Sep 17, 2012, 10:52 AM
homo ludens modellisticus
Ron van Sommeren's Avatar
Kontronik Kosmik controllers
  • 5-14 Lipo, 20-59 V
  • 200 A continuous current
  • BEC 7 A cont. current
  • 200 g without cable
Programmable reverse, very handy for taxiing

More info

Last edited by Ron van Sommeren; Sep 17, 2012 at 11:52 AM.
Nov 02, 2012, 04:14 AM
Registered User
Originally Posted by KiloOne

I have convinced myself that discharging these cells to 3.3v (nominal 100% discharge level) at my expected cruise current does not significantly affect their life.


I've operated an Electric Trike with LiPo batteries for the last three years and routinely use "3.0 volts cut off under load" :

***Golden Rule of LiPo***

1. Never Exceed 4.3v/cell
2. Never Discharge below 2.7v/cell
3. Cut Off Under Load 3.0 volts
4. Never Puncture the cells

The minimum open circuit voltage of 3.0 volts, is a safe value for LiPo cells. The minimum cutoff voltage under load is dependent on the load, with 2.5 volts under loads above 2C the battery open circuit voltage will never drop below 3.0 volts. At higher loads, say in the 10C range, the voltage drops rapidly in the first 10% of the discharge to around 3.4 volts and then is fairly linear down to where the discharge curve begins to take a dive at 3.2 volts, from this point on to 2.7 volts about 15% of the capacity is delivered. So you can understand the logic of specifying 3.0 volts cut off under load, continuing the discharge is pushing your luck for insignificant payback.

Best regards
Last edited by Schpankme; Nov 02, 2012 at 04:22 AM.
Nov 21, 2012, 11:57 PM
Your BMS is amazing. I'm on a solar car race team and our BMS is a brick in a steal box compared to what you have built. Yours can't weigh more than 4 oz.
It is truly amazing what people can do in their backyards and home workshops.

I saw some people mention solar cells and did some quick numbers on the back of a napkin (literally) and you won't gain much in flight time by the time you take into account the weight of the cells. Your looking at a weight gain of about 40 lbs for an extra 1500 watts and that is pushing it. You may gain around 15 min in flight time. I'm just estimating on the the array size but I think I'm close. Most solar cars can fit around 1000 watts of cells. Then you also have the heat trouble of the cells. Solar cells get up to about 150 - 200 deg. F because of all those electrons jumping around in them. You would need a type of covering that could take that heat. I know that someone is going to say cover it with carbon fiber or thin aluminum but that is a bad idea too because both are conductive, you will smoke your array.

Also, please see the PM I sent.


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