Electric Lazair

[Guest ozzie]

http://www.rcgroups.com/forums/showthread.php?t=1412424

 

I was going to PM this to The Major as he used to own a Lazair. But thought i'd share it around.

 

This effort at building an electric Lazair is from the designer Dale Kramer. Major has most probably met him and his employee Bob Chapman. Bob and i have been conversing since he used to work in the Lazair factory back in the early eighties and has kept me up to speed on what has been going on with Lazairs over the years. Along with designing the Lazair, Dale also has designed and flown some very high performing sailplanes over the years as well as some hush hush military stuff. Needless to say i'll be having a very close look at the electric set up for his Lazair when i am at Airventure.

 

But must say flying from his home in New York State to the Atlantic Ocean then across the country to the Pacific Ocean via Airventure at 30mph on less the 3kw for best endurance is a little ambitious for my thinking. Hope he has a comfy seat in his machine. Better start practising my begging skills if i want a go at it.

 

Ozzie

 

 

[Guest Maj Millard]

Thanks Ozzie, Good to see Dale still around further developing the Lazair. He was way ahead of his time when the first Lazair came out, and nothing he comes up with would surprise me !.............................................................Maj...

 

 

[turboplanner]

Go for it Ozzie, because the RC development of electrics has been stunning, and they aren't finished yet

 

 

[Guest Maj Millard]

Ozzie, Reg Mason at the Air Whit hangar is in the final stages of building a small scale 9 cylinder radial engine (P&W 985) that will run and swing about an 18" prop. Pistons are about the size of a 20c piece. Four of them on a Lazair would sound wicked !. I have already offered to mount it on my lightwing for in-flight flight testing, and additional take-off boost !.

 

We have named it the Pratt and Mason !..............................................................................................Maj...

 

 

[Guest ozzie]

I am amazed at how the price of motors and controllers have dropped in the last 2 years. when i first looked at the predator motors they were around 1500 dollars and the motors that Dale is using are less than 400us controllers 500. batteries still around 3,000 tho.

 

Major i am continually amazed at the skills that Reg has. I would not be surprised now at what he can build. I bet not only is it fully reliable and functioning but would be a piece of art as well. I really should have taken up the offer to work for him those years ago but i did not have the patience for the dropkicks that he had to have in the hanger with him at the time.

 

You putting floats on the Lightwing?

 

Ozzie

 

 

[Guest Maj Millard]

Yes Reg is pretty well known for his machine shop skills, and yes the little radial is becoming a very disirable work of art. We can't wait to hear it run, as you may know he doesn't waste time on things just to look at.

 

Yes I know what you mean about the dropkicks with Reg, but he has mellowed a bit, and I don't mind working with him when things are running well. It is particulary pleasing to work on the 985 radials with him, as there is nowhere he hasn't been before, and it can be a wealth of knowledge for a young bloke like me !. We've pulled a few jugs together.

 

Reg is off to Omaka NZ shortly and he attended the Wanaka airshow last year.

 

I certainly would love to do some float flying one day, but currently I'm really enjoying the LW on wheels. Maybe when it gets a bit of age on it I may seriously consider it. Realistically I should have a set of ambhib floats set up, and just do the swap-over for the better half of the year up here...Did you see that Grand Caravan on it's back at Sun and Fun. Takes some force to do that !!!...............................................................................................................................Maj...

 

 

[Guest ozzie]

Major with all the rain up there at the moment i'd have thought that floats would not be an option.

 

I bet around the area of Sun and Fun that there would be all sorts of aviation stuff still floating down from that tornado.

 

Nothing will stop future Sun and Funs the place has been flattened before and probably will be again in the future. The last night i spent at Airventure in 08 a huge storm came thru about 2am i never saw lightening like it. I crawled into the rear seat of the hire car and hid like a scaredy cat. The next day when i got down to Chicargo the tornado sirens kept going off, amazing scene. In between each line coming through they get as many aircraft as they could on their way then hold for 10 minutes then off again. Crazy stuff.

 

 

[Hildy]

those calculations look actually pretty good. the batteries are 1lb each, so 96lb worth of batteries. less than a passenger.

 

each battery is 72WH (or just under), so that's 7kWh from the batteries. so 2 hrs of flight at 3kW.

 

the real question is, is 5hp enough to take off on? I'd be pretty scared of how slowly it accelerates on ground roll.

 

ozzie: I'm in the hunter. want me to electrify your Lazair?

 

 

[Guest ozzie]

Hildy, If you have the knowledge i need the help. Building up the battery packs looks very confusing. If Dale makes it to Airventure i will be all over it and him. I do not want to put that much weight in my Lazair nor do i need that much endurance to start off with. I probably set up one side electric with 30 minutes worth. Then when i know that will be reliable and i can keep the expensive smoke inside where it belongs i'll do the other side and increase the battery pak and chargers as funds allow. First of all i have to start getting some more time to finish a wing mod (one day max) and fly hopefully over Easter when home renos are finished. I have 2 more engines to test as well and will probably have to rekit all 4 carbs as they have been sitting for a while. The fuel system on these is a real pain to set up right.

 

I think Dale will use a little more power to get airborne but it will easily cruise on 5hp. My Pioneers are only 5.5 hp @ 5,500rpm. I can loiter easily on half throttle with both running. can't maintain on one engine tho.

 

 

[Hildy]

5.5HP@5500rpm. is that each?

 

those motors claim to be more than 10hp each but I wouldn't trust them at that much. I think that tuning them for 5.5hp@5500rpm would be pretty gentle on both them and the battery pack.

 

I had a look at these motors (and the full powertrain) a year or two ago as part of an electric mini project, but have you seen the price on an old mini body? utterly crazy.

 

I'd be interested to see how well dale's flies, and what problems he has with it.

 

 

[Guest ozzie]

Yes they produce 5.5 each and 35lb thrust that's 70 total. These are the original 2stroke chainsaw engines the series one came with, they later went to the 185 Rotax. The Photo of Dale's mono float has the twin cylinder JPX engines.

 

The Turnigy CA120-70 electric motors seem to good to be true as far as price go 300.au, the Jetispin controllers around 600us pair of 32 x 10 props 130au each.

 

Along with the heat i wonder how the motors will handle pulling the weight.

 

Along with all the other electric aircraft that will be at Airventure this year Dale's is the main reason i am heading there.

 

I've really had enough of those two strokes.

 

 

[turboplanner]

The big risk is what happens to you if the batteries catch fire.

 

 

[Guest ozzie]

That has been at the front of my thoughts.

 

 

[Hildy]

yeah.

 

I once saw a battery charging bag - fireproof - designed to stop the batteries from catching fire when charging (the most dangerous portion of their life). if you ducted a bit of air you could put some ventilation into one of those.

 

if it caught fire you could claim it was a jet engine.

 

ozzie: modern brushless motors are too good to be true. they rely on technology that just wasn't there twenty years ago. basically they have no moving parts other than the magnets - they are three giant coils of wire, a bunch of high power magnets (I've rewound some micro ones using those toy rare earth magnets), and a couple of big bearings. much less complicated than a gas engine.

 

anyhow, I've come up with a conservative design using 24 of the turnigy 6S 5Ah batteries to produce 6hp at 5500rpm. I wonder how smart the jetispin controllers are. but that's $1000 in batteries, $1000 in motor & controller, and some tinkering time.

 

 

[Guest ozzie]

Yep too easy come rebuild time, two bearings and that is it. AC Delco and friends are going to hate electric cars when they are the mainstream of motoring.

 

 

[fly_tornado]

looking @ the way the Chinese manufacturers have redefined the model plane industry, a $25K electric motor glider can't be far from the market.

 

 

[Guest ozzie]

It may be worth 25 grand in China but have you noticed the incredible BS mark ups on stuff being imported from there. Those 600 dollar TV's here can be bought for under 50 dollars there.

 

 

[fly_tornado]

Its the Australian way...