# e-Lazair Info!

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#### Armilite

##### Well-Known Member
The E-Lazair is circa 2011/2012, and is a great example of what can be done by a sound mind. But 8 years later still beating the drum about how the FAA views batteries and fuel?

The problem (or limitation) for electric ultralights is battery energy density.

If you want more "electric" air time you need to go experimental in the USA. Experimental glider makes a lot of sense for electric.
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Yes, Battery Energy Density and their High Cost is a Problem, also People always wanting more, more, more HP! To get a Good Price break, like $1 per Cell on the Battery's you have to buy a lot, like 20,000. Same battery at Battery Stores$5. There Lazair Flew on (2) 5.5hp Chainsaw Engines, 11hp, was soon upgraded to (2) Rotax 185UL's at 9.4hp equaling 18.8hp, then they want to put even Higher Hp Electric Motors requiring more Battery's. Just put (2) 10hp Electric Motors with Carbon Fiber Props on it, and enough Batterys for Minimum 1hr 15min of Flight and be Happy. If you can have even more Flight Time so much the better. If you can't provide that minimum Flight Time, then go with a Gas powered engine.

Using (2) Honda GX200's making 10-15hp with an Ace Belt Drive is still the best Bang for the Buck.

If you already have (2) Rotax 185's, your better off just Rebuilding it, and Upgrading them for a little more HP if you need it.

Yep, that's 8+ Years of Lost Sales of his Lazaairs. Build what you can Sell now to make Money, then do R&D on the side.

#### Armilite

##### Well-Known Member
I wonder if they would go for a removable battery back that was 1155 in^3 (5 gal) in size?

Just as a first pass I measured the lithium motorcycle battery I use in my plane. 5.75x3.375x5.625 inches. So 10.5 of these would fit in 5 gallons. It is labeled as 48Wh and weighs 2.4lbs on my bathroom scale.
So 504Wh and 25.5 lbs. Hmm. Not enough for much of anything. Maybe a sustainer on a good glider.
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5 Gallons is a Volume Measurement. The FAA is saying the Battery Weight is part of the Airframe(254lbs). The Lazair flew on 11hp. So Redesign the Lazair for a Single Electric 15hp Motor. If you can't build an Electric Plane that can Fly at least a minimum of 1hr 15min, it probably won't Sell. A Single 20hp Electric motor is probably lighter than (2)10hp Motors.

20hp@????rpm Motor for 1hr 15min = How many Cells needed? At 75% Power = 15hp@????rpm!
Cell 18650 = ?
Cell 38120 = ?

15hp@????rpm Motor for 1hr 15min = How many Cells needed? At 75% Power = 11.25hp@????rpm!
Cell 18650 = ?
Cell 38120 = ?

A Rotax 185UL, 9.4hp@5000rpm. At 77F using a 32 x 10 Prop = Static Thrust 70.28 lbs needs 8.904 hp!

At 75% Power = 7.05 hp!

At 60% Power = 5.64 hp! The original Chainsaw Engines were rated at 5.5 hp!

#### litespeed

##### Well-Known Member
I might have the solution for you poor buggers with part 103.

The Lazair is covered in a clear plastic material.

You can now get ultralight printed organic solar cells using the same type of printer as a sticker/label printing machine. They are developed by CSIRO our national science group, so are the real deal.

The stuff is strong and light not as powerful as glass cells but, when covering an entire wing and maybe fuse top and sides plus tail, that is a lot of area for power at a small cost of weight.

As CSIRO says "1000 square metres of organic solar is a little heavier than an average adult male (100 kg). Compare that to traditional silicon solar, which would weigh the same as 3 large african elephants (11 tons)!"

Weight is 100grams a square metre, that is light when you consider it is also a power source as well as wing covering. Thus a 10 m square wing cover is 1kg or 2.2lbs, assuming they have their weight correct- that is **** light.

#### proppastie

##### Well-Known Member
Log Member
The obvious question is anyone selling this stuff yet?

#### litespeed

##### Well-Known Member
They are currently setting up and doing demonstration projects. The are in the process of commercialization and should be available in next two years on the market.

Given the time taken for engines etc to be available, that is not long to wait.
I would bet a builder would be able to get some as a development test for aviation. If they were approached properly, it would be a winner for them.

The promotion alone would be gold.

#### Armilite

##### Well-Known Member
I might have the solution for you poor buggers with part 103.

The Lazair is covered in a clear plastic material.

You can now get ultralight printed organic solar cells using the same type of printer as a sticker/label printing machine. They are developed by CSIRO our national science group, so are the real deal.

The stuff is strong and light not as powerful as glass cells but, when covering an entire wing and maybe fuse top and sides plus tail, that is a lot of area for power at a small cost of weight.

As CSIRO says "1000 square metres of organic solar is a little heavier than an average adult male (100 kg). Compare that to traditional silicon solar, which would weigh the same as 3 large african elephants (11 tons)!"

Weight is 100grams a square metre, that is light when you consider it is also a power source as well as wing covering. Thus a 10 m square wing cover is 1kg or 2.2lbs, assuming they have their weight correct- that is **** light.

They are organic printed cells and are non toxic unlike current cells and expected scaled costs is \$10 a square metre, that is extremely cheap. They are been developed by University of Newcastle Solar research centre which is a world leader- Australia has lead the world in solar for 30+ years. The efficiency is around 10% not brilliant but a good start. So assuming 100 watts a metre adds 1kw in the sun of charge. Thats just the wings. Add in the tail and eppenage of a suitable design and you could get 2kw of energy free.

That 2kw might not sound much but can help sustain flight and charge when not flying. A suitable design with motorglider like features optimized for solar could be a real winner.

As far as batteries go - the LIPO are the the go power density wise. You just have to manage them very well and design a box that can take abuse and not deform the cells. Think of them like fuel as in flammable. Also the idea of placing them on the Cof G and dropping them in a emergency has merit. Could even add a little chute.

Loosing that chunk of weight and potential fire risk in a emergency could be a life saver. It increases your glide, reduces stall speed and if it all goes to hell- reduces the momentum of the crash. Most part 103 do not have much in crash protection so everything would help.

I understand the Lazair is not suited to all the above but some of the ideas could help.

I agree with the single engine. Much lighter, bigger flywheel effect, more efficient and can drive a much bigger prop thus greater thrust for the power. And all we really care about is thrust. Also only one controller so costs, weight etc.

**** pity you are stuck with silly rules- if you were allowed the 661 lbs as a max weight and just had to meet stall speed that would be a huge difference.

Oh and another cat amongst the pigeons.............Carbon airframe used as the battery- tech been developed now.
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I have always wondered if their stuff could be used to Cover a Tube & Fabric Ultralight.

If the updated Lazair with (2) Rotax 185's took off and flew Good on just 18.8hp, and the early Lazair used (2) Chainsaw Engines equalling 11hp to takeoff and flew with less HP, then using a Single 20hp ought to be an Improvement. Say Full Power for Max 3min for takeoff, then Cruise at say 12-14hp. Big Question is, How many Cells needed for minimum say 1hr 15min of Flight, and How much could using this Solar Covering Help to maybe Extend your Flight Time?

Something like the Mitchell A10/B10 Flying Wing might be better suited for a Conversion since it used a Single Engine.

A10 Specs.
https://en.wikipedia.org/wiki/AmeriPlanes_Mitchell_Wing_A-10

B10 Specs.
https://en.wikipedia.org/wiki/Mitchell_Wing_B-10

#### litespeed

##### Well-Known Member
Assuming using 10kw hr and a covering of 12m squared gives 1.2 kw hr, so a good 5-6 mins.

#### Armilite

##### Well-Known Member
Assuming using 10kw hr and a covering of 12m squared gives 1.2 kw hr, so a good 5-6 mins.
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First, you have to take off all Nonessential Parts for say a Lazair Conversion, (2) Rotax 185UL's, Fuel Tanks, Exhaust, Gas lines, etc., to see how much weight you have to Play with. Converting the Airframe to a Single Electric motor would take some Engineering, but let's keep it simple, say we keep the same dual motor concept, use say (2) 12hp Motors, gives an upgrade from (2) 9.4hp Motors.

Max 24hp for 3 Min Takeoff = ???
For 1 hr 15 min at 75% = 18.0 hp = ??? Batterys needed? <-- (2) Rotax 185's 18.8hp
For 1 hr 15 min at 70% = 16.8 hp = ??? Batterys needed?
For 1 hr 15 min at 65% = 15.6 hp = ??? Batterys needed?
For 1 hr 15 min at 60% = 14.4 hp = ??? Batterys needed?
For 1 hr 15 min at 55% = 13.2 hp = ??? Batterys needed?
For 1 hr 15 min at 50% = 12.0 hp = ??? Batterys needed? <-- 1.0 hp more than original (2) 5.5hp Chainsaw Engines.

For 10 Min Reserve = ??? Batterys needed?

Total Batterys needed x Cell Weight?

Original (2) Rotax 185's with 5 Gallons gives you 2 hrs of Flight.

Could a Rotax 185 be upgraded to EFI, use a Tuned Pipe to make more HP at a Lower Rpm, Yes.

Just a +CR Increase and a Bigger Carb and a better Muffler can Increase it's HP.

Just adding a Wide Ban Tuned Pipe.
9.4hp@5000rpm + 20% = 11.28 hp
9.4hp@5000rpm + 25% = 11.75 hp
9.4hp@5000rpm + 30% = 12.22 hp
9.4hp@5000rpm + 35% = 12.69 hp
9.4hp@5000rpm + 40% = 13.16 hp

A Rotax 277UL Dynoed 25.4hp@6000rpm = 65% Volumetric Efficiency with a muffler! A 185 with a Bigger carb and higher CR for a 65% Volumetric Efficiency at 5000rpm = 14hp, at 4500rpm = 13hp, at 4000rpm = 11hp, at 3500rpm = 10hp, at 3000rpm = 8hp. The lower the rpm the Bigger Prop you can use.

Standard 32 x 10 Prop at 5000rpm = Static Thrust 70.28 lbs need's 8.904 hp.

A 46 x 11 Prop at 3000rpm = Static Thrust 108.04 lbs needs 9.034 hp.

#### Christian Moreton

##### Active Member
Many thanks all for having this discussion.

I just got my hands on #906 and am planning on going brushless. RN looking at making 24s Li-ion packs and these motors.