Converting a MONI motor glider to electric

Things that fly
topspeed   10 mW

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Joined: Sep 07 2020 12:30am

Re: Converting a MONI motor glider to electric

Post by topspeed » Oct 06 2020 4:27am

Hillhater wrote:
Oct 05 2020 2:24am
topspeed wrote:
Oct 04 2020 2:23am
Munro claims the new Tesla battery will reduce the battery weight in half.
Well,.... He is wrong ! :roll:

I kinda agree..it may be even heavier ?

helno   10 W

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Joined: Apr 10 2017 2:23pm

Re: Converting a MONI motor glider to electric

Post by helno » Oct 06 2020 8:44am

topspeed wrote:
Oct 04 2020 2:23am
Munro claims the new Tesla battery will reduce the battery weight in half.
Half the empty weight of this aircraft is still to much to allow it to fly.

This is a conversion it is not a new build. The power system has to work with the weight and balance as is.

Luckily the original airframe had a large amount of ballast installed on the motor mount which means that this should be possible with no permanent airframe modifications

mparker333   1 µW

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Re: Converting a MONI motor glider to electric

Post by mparker333 » Nov 01 2020 5:27pm

I also have a moni that I plan to convert. Looked into it a few years ago but got sidetracked. Maybe something like this works for a motorglider like the moni.

3 Motors, 3 Motor Packs
100% Power 20.62 Kw 86% eff
Takeoff + Climb 10.00 min 5000' AGL
Climb Energy 1.33 KwHr
Energy left 4.66 Kwhr
Cruise Power 6.00 Kw 70 MPH
Cruise Duration 46.62 min
Distance 66.05666667 miles

I was thinking 75lbs of batteries, 20 lbs of motor (or (3) 6lb motors (Rotomax 150CC),
Belt drive to center prop shaft.
Think the Tesla battery packs are about 70Wh/lb but maybe a different design for flight would be lighter (different
requirements). I've gained about 20lbs since then, so gotta lose that (1.4KWh worth :) )

Never did finalize on what kind of prop though. Yes, the ground clearance limits the prop size. Thought about this one but it's probably way off.
Dia 39
Pitch 29
RPM 3000

Will be listening in to see how it goes. Best of luck!

mparker333   1 µW

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Re: Converting a MONI motor glider to electric

Post by mparker333 » Nov 01 2020 6:16pm

Nice motor (Emrax 188)! Weighs about the same as 3 of the rotomax 1500's, but it definitely has more than 3x the power.
How much do they cost? I'm cheap, think that's why I was thinking 3 big model airplane motors (about $500 each)

BTW, watch the weight and balance from the start. If you don't want to have too much trouble, plan on putting as much weight up front as the 2 cycle (25lb + 40lb ballast??). Since that motor only weights about 16lbs you should plan on at maybe 50lbs of batteries ahead of the firewall (is it still called that in an electric plane :) ). My gas tank is 6 gal so that's worth 36 lbs between your legs.
Where the rest goes is all up to W/B. I was planning on having about 85lbs of batteries because of cost (maybe $200/KWh)? However if I had more $ I would make room for "battery pods" to increase the flight time and place them appropriately. Think 85lbs would give you about 500-525 lb gross weight (with a 180lb pilot---which I will be again someday :) ). Going beyond that might be ok, but the g rating would go down (original rated for 6g? I forgot).

helno   10 W

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Joined: Apr 10 2017 2:23pm

Re: Converting a MONI motor glider to electric

Post by helno » Nov 10 2020 10:10am

Do you have a detailed W&B from the original builder? If you need a copy of the sheet to do the math I have the forms from the factory.

There is a lot of dead weight on the front end of a Moni since it was originally intended for a larger motor. The ballast in mine weighs more than the motor and double walled exhaust system.

emotofreak   10 mW

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Joined: Nov 24 2008 12:35am

Re: Converting a MONI motor glider to electric

Post by emotofreak » Nov 19 2020 4:35pm

I have a sweet electric package that would work perfect for you guys.

https://www.youtube.com/watch?v=rxfMx5OX_yk

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