Series Hybrid into Plane, need help

14570 Views 39 Replies 8 Participants Last post by DaDeemster, Aug 8, 2013

DaDeemster

Discussion Starter · Jul 18, 2013

Hello all, after spending a decent bit of time polishing back up on my electrical knowledge i decided i'd finally move on to the public feedback stage of my plan, this is my first post On this awesome forum. I'm aware of this not being an airplane forum , but with this being the goto place for all things "electric vehicle" i figured it couldnt hurt

The objective of this build is try and find a clever way to shoehorn all the necessitys of a typical series hybrid into the plane without the plane tipping the scales, and cost effectively.

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Ok so the build is to be based in one of the following (its not important to have alot of plane backround knowledge) they are 20k and under planes with relatively a decent positive history

Sonex aircraft -http://www.sonexaircraft.com/
Pulsar Xp - http://pulsar-airplane.com/
Sonerai II - http://www.greatplainsas.com/sonerai_ii.html

**The Ac electric motors i'm leaning towards** are the Enstroj Emrax motor and the Hpevs ac51-76.
But since the Motors are comparable and the Emrax has a drastically better power to weight i'm gonna go with it (22lbs roughly) i was considering possible two so as not to stress the motor , unless new affordable alternatives have been released SO-

Emrax 228 - http://www.enstroj.si/Electric-products/emrax-motors.html

** Motor For Generator ideas** - (thinking compact, powerful (for when i need to bump the rpm's up to get the batterys some immediate juice

**This is the Dyno of a ICE motor that is slightly more powerful then it needs to be for the drive motor application -
http://www.aeroconversions.com/products/aerovee/
http://www.aeroconversions.com/images/products/HP-Torque_graph.jpg

-The motor im wanting to use to power the On Board Dc Generator is a ar741 rotary wankel motor from Uavenginesltd.com ( thier site is semi down)
i was able to find one on the internet
-i was also able to find a 30-40 horse sachs rotary motor, pull start
-i also found some running vintage snowmobiles that have the 38hp Sachs rotary motor

^^ will these motors suffice my generator power needs? direct Hp to Kw conversion wise they do even at peak torque range but is that all that matters?

Which brings me to my next dilemma, and this is where things start getting hazy- My Dc generator needs be able to directly convert as close to 100% of the rotary engine output power as possible but i dont know what dc generator make/size is best for matching it to the motors above. or if i need to run a reduction drive (i'm thinking not)

Secondly, is it really as simple as hooking the rotary to the generator and then finding a way to hold it at preset throttle positions for different charge rates
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Can it go straight from the Dc Generator to main battery terminals? and if not then what is the direct most way. Also does Generator need modifying

Also has anyone had any experience with foreign batteries? I've only heard non educated guess'. The deals are amazing and look well put together

-http://www.aliexpress.com/item/lifepo4-battery-pack-48v-55ah-electric-wheelchair-batteries-scooter-battery-with-bms-BOGO/898298740.html

-http://www.aliexpress.com/item/customized-lifepo4-60v-40Ah-Battery-pack-for-electric-vehicle-with-BMS-and-8A-faster-charger/708769853.html

And based off of someones post in this forum and the recommended voltage range for the motor i'm thinking the second battery link option would be best since its more voltage mediocre amp hourage , but since i will be so many batteries above the voltage i need to make it to run consistently so i can just enjoy the benefits of a big pack with so-so amp hours (around 180-220lbs)

Also i'd probably use the Medium- High Voltage motor controller options that they have available on thier site

But to stay in theme, if anyone has alternatives that i could use. and also thoughts on using one heavy duty controller for Dual Emrax motors. They said its not what they would recommend but i'd like to know more anyway. two motors sounds like less wear on each motor plus it would give me a instant additional power range without putting strain on a single motor. but i'm kinda confused on this . If im applying 20kw continuous from the controller to the motor will it perform the same with dual motors under the same 20kw contin' on dual motors? and if not what would be different besides more potential torque? Would i need 40kw from the motor controller to get the same desired rpms? or would the dual motors be suffice with same 20kw from the controller?

P.S i know i'm new and i pretty much wrote an article but feel free to take your guys time responding, i have a feeling i'm gonna be on this site for awhile lol

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Floridabrokerpilot

· #3 · Jul 18, 2013

DaDeemster, the planes you mentioned are questionable for being right for the electric conversion, except one the Sonex. All have flown with low power plants, but two are very slick and clean requiring more power than the minimum stated for them to fly well. I have followed two different builder forums and nearly everyone flying now has installed the largest power plant available. I have followed both of the planes, the Sonerai II, and the Pulsar for many years and they are both great candidates for making a good cross country airplane but bad electric conversions. Fast slippery planes need a good deal of constant power to stay happy, something the modified Sonex does not need or the motor glider. They both have longer than needed wings, high aspect ratio for greater lift at a given speed resulting in a low drag, medium speed performance airplane. Motor glider airframes would be the best candidates for conversion since they have the ability to fly for some time without power, so the loss of electric power is not an immediate concern. If you keep the weights correct and CG in the design envelope, one of them should make a very good conversion. Match the engine output rating to the factory recommended gas engine output, and keep the battery volume within weight limits, and you can have a great self launching motor glider that can stay aloft for a long time, then power back home. That is the best of both worlds. not sure how good a cross country flyer it would make if that is your goal, but a fun local bird for sure. Good Luck!

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Floridabrokerpilot

· #12 · Jul 22, 2013

Two problems I see with using the planes you mentioned to copy the idea of Diamond: 1) is weight. The 13B motor and needed accessories to make it work right in the airplanes you suggest will be far too heavy. You need a much smaller engine like a 5 hp Briggs to be dedicated to a generator. Locating much of anything beyond 30 pounds in the tailboom of most any airplane, without significant ADDITIONAL weight added (now more to lift) to the nose will make the plane not only dangerous to fly, but possibly uncontrollable. Look at most designs, not much of anything besides the necessary controls are in the tail boom.
2) The planes you are talking about require almost their full rated horsepower to maintain level flight which is why you climb at such a low rate and high speed. I own a Grumman AA1 with the speed wing and can tell you from first hand experience that it is NOT a plane you want to lose power with. Both of the other planes mentioned cruise at 5 to 6 gallons an hour when you add the needed fuel to climb to any decent cruising altitude. Both of those other planes have very low payloads; one of the reasons so many are for sale though the owners won't admit it. Once they get in with full fuel, no one else can go unless they want to fly dangerously over weight.

I suggested the sail plane type platforms, which is what the Diamond electric is copying-theirs, because the loss of the engine power does not mean an emergency. You can still glide for some distance, maybe to another airport even, where as the short wing versions of what you suggest will glide a few short miles; everywhere besides Florida that means ditching or landing somewhere you don't want to! The Sonex is even the longer wing version V-Tail for minimum drag and max lift so that the electric engine does not work as hard to achieve and maintain lift.

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