DIY Electric Car Forums banner

1 - 20 of 40 Posts

·
Registered
Joined
·
19 Posts
Discussion Starter #1
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.

-
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
-
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
 

·
Registered
Joined
·
2 Posts
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! :)
 

·
Administrator
Joined
·
6,167 Posts
Hi Dadeemster

Why serial hybrid?
Each time you convert energy the gods of thermodynamics take a bite

Fuel - mechanical power about 30%
mechanical power - electricity - about 85%
electricity - mechanical power - about 85%
(If it goes into a battery then there are another two bites taken out)

The two 85% together are 72% - so you are losing 28%!

(And NO you will not get a large increase in efficiency using a smaller motor)

Better would be to use a parallel hybrid

With this you would use the IC engine to drive an AC motor/generator and the prop

In cruise the AC motor/generator would be effectively just a driveshaft

For more power use the electric motor, to recharge the batteries use the motor as a generator
 

·
Registered
Joined
·
19 Posts
Discussion Starter #5 (Edited)
I'm liking where your coming from but before i go onto discussing parallel i'll give you the logic im working with at the moment

1.I figured i'd be using emrax 228 which hovers in 92-96% efficiency ( so thats pretty decent )

2.I barely thought of it going into the battery as a loss before , because i would be using about 110% of the generators output at cruise

3.I wasnt mentioning the rotary for just its sheer size , but more so for the fact that its small but has a higher cc equivalency, for example the 13b (1.3l) mazda is said to be the displacement equivalent of a 3+ Liter piston motor , yet makes its power over the course of a wide (higher rpm) power band. this all saves weight and cabin room since in a series hybrid i could tuck the mighty mouse rotary ICE motor in the back of the plane behind a shroud , which is typically a wasted awkard dimensioned trunk-ish space in the plane'

4.One of the major benefits of a solo electric drive motor is that during the annual inspection which charges by the hour , if you have a simple EV setup there is drastically less inspection points and things they can hassle you over.
inspections can cost anywhere from $500-$3000 depending on how small and simple or vice versa it is
-------------

Now on to the Parallel talk, I regret having put "series" hybrid into my threads title because i'm fairly open to the use of parallel but i'm not quite getting its benefits and execution quite yet , You said -

Hi Dadeemster

Why serial hybrid?
Each time you convert energy the gods of thermodynamics take a bite

Better would be to use a parallel hybrid

With this you would use the IC engine to drive an AC motor/generator and the prop

In cruise the AC motor/generator would be effectively just a driveshaft

For more power use the electric motor, to recharge the batteries use the motor as a generator
Are you proposing that i put both the Ac emrax and a Small Ice on the Same propeller drivetrain? like two motors literally parallel to each other, under the hood linked to the propeller via some chain drive or some thing? Sounds efficient but also like alot of moving parts and hot motors in close proximity to each other ( i'm sure there are cooling solutions tho). Also if the Ice engine has to spin the prop and the ac motor/regenerator wont that just put more work on the ice motor thus affecting efficiency rates ? and how could you use ice engine and electric at the same time and also recharge ?

and can someone please elaborate the whole Charging a battery with a generator/ motor of some kind ?

i'd like to know the different methods routes to take on this for example

Ice engine -> DC generator -> DC to battery
Ice engine ->AC Emrax motor->??Controller, inverter, converter??->DC Battery

which is best for recharging a lithium battery ? i figured a regular ice engine /dc generator would lose the least efficiency since its not going ac->dc to charge the battery but instead going directly to the battery
 

·
Registered
Joined
·
19 Posts
Discussion Starter #6 (Edited)
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! :)

Thanks for the input , i'm also in florida so i was kinda looking for a state / just outta state touring plane . i thought the pulsar might have been ok because mpg wise its very comparable to the sonex and the pulsars have been known to use the 65hp rotax 582 whereas the sonex flew with the 80hp aerovee engines minimum

the emrax has the same capabilities and then some over the rotax and it uses less Kw to produce the same amount amount of torque and a higher rpm range . Another benefit of the emrax is that the torque is there right off the 100rpm line whereas the bigger aerovees dont hit peak torque until 2400rpm

my thoughts were , if rotax is smaller then aerovee and emrax is equal to or in some ways better then the aerovee then powerband wise i should be better off then both right?

Also motorglider and xenos ftw but they are both hard as hell to find used . whereas you can get a regular sonex/sonerai/pulsar anyday of the week if you look hard enough . a xenos you'll have to build and will start costing corvette money by the time your even lookin at motor options.

If i could even get 250-300miles without landing i'd be happy because its not like with a car where you just pull over, your up in the sky lol.

also lets say a sonex uses 2 gal over 3 hours and goes 60miles (high lift low speed) and a pulsar used 2 gal over 2:30 hours and goes 60mph ( fast and slick) although the slick pulsar has more trouble staying aloft wouldnt it boil down to mpg because more time spent in the sky doesnt mean i went farther?
 

·
Registered
Joined
·
133 Posts
do correct me if i'm wrong, but what i feel is different with a plane and a car/truck is that planes usually run at fairly constant rpm. so a series hybrid will work for an automotive platform where you get the engine to run constant, while the motor does the peaks etc. however for a plane, since you only have one up and down "cycle" each trip during take off and landing, you're running most of it at a fairly constant rpm and hence fairly constant fuel consumption.

The parallel hybrid sounds interesting, and I havent put much thought into that yet. but to me, maybe sticking to an ICE engine all the way may be the easiest option altogether.
 

·
Administrator
Joined
·
6,167 Posts
The only serial hybrids I am aware of are trains and BIIIG trucks (mining trucks)
And these are serial because of advantages in the drive train (lots of wheels to drive) despite the inefficiencies!

Now Parallel hybrids are common, Prius, Volt

For a plane you could use a smaller IC engine and use battery power to augment for the take-off and climb

All electric motors are also generators (some are easier than others)
For a plane I suspect brushes will be a NO NO - so you are stuck with AC
(all the brushes do is convert DC to AC)

I envision your IC motor back in the middle of the plane
You will have a long driveshaft to the prop (possibly with a gear down system)
Your electric motor will be in the middle of the long driveshaft

Take-off and climb
The IC engine will be on full power and the electric motor will also powering the driveshaft and the prop

Cruise
The IC engine will be driving the prop - the electric motor is just there for the ride

Re-Charge - if you want to, cheapest is to plug it in back home
The IC engine is running a bit more than cruise and the motor is vampiring a bit of power off it to recharge the batteries while most of the power is going through to the prop

Not at all sure it is worth the extra complexity

You could have something like the Voyager (Bert Rutan) with a tractor prop at the front powered by the IC and a pusher prop at the back powered by the electric
No re-charge with that setup
 

·
Registered
Joined
·
19 Posts
Discussion Starter #9
do correct me if i'm wrong, but what i feel is different with a plane and a car/truck is that planes usually run at fairly constant rpm. so a series hybrid will work for an automotive platform where you get the engine to run constant, while the motor does the peaks etc. however for a plane, since you only have one up and down "cycle" each trip during take off and landing, you're running most of it at a fairly constant rpm and hence fairly constant fuel consumption.

The parallel hybrid sounds interesting, and I havent put much thought into that yet. but to me, maybe sticking to an ICE engine all the way may be the easiest option altogether.
when planes are going up and going down and have 80 or less hp they are lots of times are at full throttle, dumping as much gas as possible to keep the rpms barely climbin (if at all) through the torque range.
which keeps the plane at a decent rate of climb. but gas motors typically arent very efficient at max load/max acceleration, well atleast i didnt think so.

a few other things, I'd rather the plane be all electric then not at all, and seeing as how building a DIY electric plane with the capability of of loading up 2 people and flying a couple hours seems far from impossible ( some first attempt successes have already been completed and flown, i.e the links i had posted previously), i kinda figured that if people could get additional range just by bringing a generator onboard of thier EV's whether it be a tow along or a 10-15kw in the bed/trunk. then theres no reason why i shouldnt be able to get the same effect especially if i am dispersing the custom gen-set's current into a large enough pack (to avoid battery stress/swelling/electrical heat loss)

The rotary design lets me take a more Capable (more kw/compact/less weight) custom gen-set up with me and because of its benefits i could use the weight savings to bring up a small fuel cell with me

excerpt--"Based on Diamond Aircraft's HK36 Super Dimona, the E-Star's propeller is powered by Siemen's 70 kW electric motor. A small Wankel engine, supplied by Austro Engine, acts as a generator, supplying juice to the electric motor. Siemens says that fuel consumption is exceptional due to the combustion engine spinning at reduced RPM. An on-board battery pack, provided by EADS, gives the lightweight aircraft a boost in power during takeoffs and climbs. That battery pack is then recharged while cruising. During initial test flights, the DA36 E-Star was airborne for two hours."

http://green.autoblog.com/2011/07/03/siemens-diamond-aircraft-eads-unveil-worlds-first-serial-hybr/
 

·
Registered
Joined
·
19 Posts
Discussion Starter #10
Also this --

The idea is valid, but what really makes series hybrid worth it, is not a small amount of batteries but a large amount. Those days with expensive and heavy NiMH cells are over. Now it makes economically and technically sense to have 30-50 km of full electric range, and all hybrids should be made plug-in.

This also has the point most people forget to mention: if you buy a larger battery pack, you can get more power out of cheaper low-power cells. For example, if you built a pack that can run 2 km electric, you would need to buy special power cells that are more expensive. If you build a 10x larger pack with the same cells, you get not only 20 km electric range (actually a bit more!) but also 10x higher output power (for higher speeds & acceleration). In practice, if you don't need all that power, you can then switch to a cheaper cell -- from so called "power cells" to so called "energy cell", latter of which is optimized for low weight and low cost (EV use). Larger pack = better battery efficiency, more power (= better acceleration at higher speeds), less need for cooling, and what goes without saying, more range.

Also, the energy recoverable from regenerative braking and the benefit running the ICE at optimum RPM (traditional points of having a hybrid drive with a small battery pack) is not so much; you may lose it in the series hybrid losses. The large battery pack changes the game by making your car a plug-in car. Then you mostly drive with electricity from the wall and only need gasoline for longer trips, and even then only for a part of the trip.

Expect to spend $2000-$3000 in lithium battery cells and you'll get decent electric range and power. You'll get this investment back in about 5 years in saved gas. A proper lithium pack lasts for at least 10 years.


Well, to be really usable, your range extender would need at least 10 kW (13 hp) of electrical power. With your truck, that would probably have you go at maybe 60-70 km/h on average with gasoline. With a largish battery, this would truly be average speed; for example, it would charge the batteries while you stop for a break. (You could also charge from a public charging point at the same time.)

So I guess a 125-250cc motorcycle engine ain't enough, unless it's only for emergencies and you are fine with a "limp mode" or extending the range only a bit. I think you need to go up to around 500cc or more. The engine and the generator will weigh more than 100 kg.


Most seem to be, but I'm also thinking about converting a pickup to a plug-in series hybrid with a 10..15 kW generator and full electric range of about 50 km.
that came from -- http://www.diyelectriccar.com/forums/showthread.php/series-hybrid-vehicle-p358651.html#post358651
 

·
Registered
Joined
·
19 Posts
Discussion Starter #11
If anyone doubts the potential for application of series hybrids, wiki has pretty credible section on it - http://en.wikipedia.org/wiki/Hybrid_vehicle_drivetrain#Series_hybrid

The electric driving motor may run entirely fed by electricity from a large battery bank or via the generator turned by the internal combustion engine, or both. The battery bank may be charged by mains electricity reducing running costs as the range running under the electric motors only is extended. The vehicle conceptually resembles a Diesel-electric locomotive with the addition of large battery bank that may power the vehicle without the internal combustion engine running. The generator may simultaneously charge the battery bank and power the driving electric motor that moves the vehicle. The battery bank acts as an energy buffer. An advantage is that when the vehicle is stopped the combustion engine is switched off. When the vehicle moves it does so using the energy in the batteries. This reduces kerbside emissions greatly in cities and towns. Vehicles at traffic lights, or in slow moving stop start traffic need not be polluting when stationary.
In some arrangements when high levels of power are required, such as in vehicle acceleration, the electric driving motor draws electricity from both the batteries and the generator. With the Chevrolet Volt if the battery bank is depleted the vehicle may run entirely with electricity provided only from the generator. Some prototype vehicle designs such as the Volvo ReCharge and Ford F-Series pickup have electric motors in wheel hubs reducing the need for a differential saving weight, space and power being sapped by the differential. Series-hybrids can be also fitted with a supercapacitor or a flywheel to store regenerative braking energy, which can improve efficiency by clawing back energy that otherwise would be lost being dissipated via heat through the braking system.
Because a series-hybrid omits a mechanical link between the combustion engine and the wheels, the engine can be run at a constant and efficient rate even as the vehicle changes speed. The vehicle speed and engine speed are not necessarily in synchronization. The engine can thus maintain an efficiency closer to the theoretical limit of 37%, rather than the current average of 20%.[3] At low or mixed speeds this could result in ~50% increase in overall efficiency (19% vs 29%). The Lotus company has introduced an engine/generator set design that runs at two speeds, giving 15 kW of electrical power at 1,500 rpm and 35 kW at 3,500 rpm via the integrated electrical generator.[4]
As the requirements for the engine are not directly linked to vehicle speed, this gives greater scope for more efficient or alternative engine designs, such as a microturbine,[5] rotary Atkinson cycle engine or a linear combustion engine.[6]
General Motors in 1999 made the experimental EV1 series hybrid using a turbine generator set. The turbine weighed 220 lb (99.8 kg), measured 20 inches (50.8 cm) in diameter by 22 inches (55.9 cm) long and ran between 100,000 and 140,000 rpm. Fuel consumption was 60 mpg-US (3.9 L/100 km; 72 mpg-imp) to 100 mpg-US (2.4 L/100 km; 120 mpg-imp) in hybrid mode. Depending on the driving conditions, a highway range of more than 390 miles (627.6 km) was achieved. The results were highly successful, and would have promised to be more successful if a smaller microturbine was used, yet the EV1 project was dropped.
 

·
Registered
Joined
·
2 Posts
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.
 

·
Administrator
Joined
·
6,167 Posts
If anyone doubts the potential for application of series hybrids, wiki has pretty credible section on it - http://en.wikipedia.org/wiki/Hybrid_vehicle_drivetrain#Series_hybrid

Credible - BUT wrong
Those efficiency figures are nonsense -
It's like comparing a 1960's V8 with a modern 4 Cyl,
Restricting the speed range MAY buy you a 10% increase in efficiency

The only way it will get you a 50% increase in efficiency is if the engine was very poorly optimized in the first place

Also note
The Volt and Prius are both parallel hybrids - NOT series
 

·
Registered
Joined
·
74 Posts
Why?

As I see it you get much more weight, more potential for unreliability, more cost, more maintenance, lower efficiency and you're moving hazardous stuff into the cabin behind the firewall and out of the cooling airflow it will need. You're also likely to upset the CoG to the point where you're carrying ballast in the nose reducing performance further. Additionally you don't get the clean and silence of the electric solution nor the well understood simplicity and reliability of a small aero engine. The conversion inefficiencies and added weight mean you're very unlikely to see any gain in efficiency over a properly selected internal combustion unit driving the prop directly.

Sorry to be negative about this but unless you're certain of what you're doing this is waste of time and money, go one way or the other. Series hybrids really can be awesome... in locomotives and quarrying equipment but this seems like picking a solution then shoehorning it into a problem almost entirely created by the solution!

jk
 

·
Registered
Joined
·
19 Posts
Discussion Starter #15 (Edited)
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.
thanks for the great food for thought, I've actually been looking at the motor-glider styles, mainly the xenos (long wing stretch sonex variant) and the europa xp with Long wings aftermarket option which would also give me the engine out safety margin and high L/D ratio, coupled with distance at altitude.
--
automatically from the the suggested gross take off weights you can subtract two major contributors of the weight and replace them with EV components-

The Installed Ice engine weight- Alternator, water pump, radiator, reduction drive, Oil, fuel tank, exhaust, intake/carb. Think about approx 240lbs-340lbs. Which i'd like to highlight are all "efficiency losses" as well and that most Engines are given a slightly overestimated Hp rating at the shaft and do not account for any "efficiency/ power losses"

Fuel weight- gas weighs 6.1lbs per gallon so say at max 17 gallon tank with a 2-3 gallon reserve = 112-122-132. Keeping in mind some planes have much larger tanks

total- 350(doubtful)-440(likely) +520(still likely)

--
I didnt account for CoG for flight and no doubt that throws me off but not the idea isnt broken .

When i said small small rotary i wasnt thinking mazda whatsoever (other people made rotarys) namelys sachs ,aixro, rotron and i think uavenginesltd never stopped making them they all weigh drastically less and can be found here

http://www.youtube.com/watch?v=fEbYyx3NRH4
http://www.youtube.com/watch?v=9JpYvjh14nk
-

I'd also like to highlight a few points of the ev adaptation such as weight and the goal that i'm attempting to achieve .

batteries and management wiring/ Controllers would be the bulk at 380-500lb
emrax motor- 24lb
emrax generator- 24lbs
Sachs 303cc with Carb Mod -24lbs

with a better L/D ratio , its still HIGHLY plausible albeit maybe difficult on the builder/engineer's part

these lsa/motorgliders are capable of gliding for 30+ minutes after cutting out the motor and 30+ miles , provided i can cruise at 110-115 for an hour if i slow it down to motorsoaring high altitude speeds that its design is centered around aka 60-85 i will get better power consumption and would easily be able cover larger distances, take into account the following Plane manufacturers capability speculation on the subject back in 2007-08 which btw is 5+ year old technology and with no range extender

http://www.aeroconversions.com/e-flight/images/Endurance_Chart_2.jpg

And i would only use the Custom high capacity generator for the trips out of state. and even then i would use probably only say 4-6 gallons for power generation on such a small motor and because almost the entirety of the trip will have been from plugin electricity all those efficiency numbers only apply to the time the generator spends in operation, local trips , and 100 dollar hamburgers become teeny burger bites

Other points : I dont car bout silence, just use creative baffles for exhaust design or figure out how to get small wankel under the hood
-i dont care about speed , i'd prefer overall distance/ motorsoaring/ relaxed touring characteristics

" simplicity and reliability of a small aero engine" - ICE motors have alot of things that can "Just Happen". I love them as much as any gearhead but they arent perfect and teardowns are a pain and cost plenty of money and time
 

·
Registered
Joined
·
19 Posts
Discussion Starter #16
also,

a europa xp w/out all ICE Components - 6500-14,000 dollars
a europa Complete with all ICE components- 23,000-60,000

this means if i bought one for 7500-10k ( Value based on 3 ads from last 2 days) then i'd have 10k-14k of spending room allotted before i hit the base price of whats on the market today
 

·
Registered
Joined
·
74 Posts
" simplicity and reliability of a small aero engine" - ICE motors have alot of things that can "Just Happen". I love them as much as any gearhead but they arent perfect and teardowns are a pain and cost plenty of money and time
Don't get me wrong, I'm far from being anti electric or pro ICE for the sake of it. I just think that as a project at the moment it doesn't stack up. You're adding weight, cost and risk for no additional gain. You're effectively cramming 3 power plants (ICE plus 2x 3phase generator/motors), two energy sources and two high power inverters and a lot of bracketry to tie it all together in in place of one ICE... I know they can go pop unexpectedly but which of those two options sounds more likely to develop gremlins and realistically, which is going to be heavier :(

Personally speaking as as a glider pilot and an electronic engineer, given your stated goals I'd go for a nice standard 'off the shelf' self launching motorglider if it's the flying you're interested in. Second choice, with a much bigger budget and pretty well purely for the pleasure in the project and for quiet flight I'd go for an electric conversion on an existing self launching motorglider. Sell the ICE to pay for some bits. Seems like an expensive option to me but then I think the regulatory environment is a little different over there. A battery fire would be my main concern, pretty much every other powertrain failure in an SLMG you'll walk away from.
 

·
Registered
Joined
·
19 Posts
Discussion Starter #18 (Edited)
Don't get me wrong, I'm far from being anti electric or pro ICE for the sake of it. I just think that as a project at the moment it doesn't stack up. You're adding weight, cost and risk for no additional gain. You're effectively cramming 3 power plants (ICE plus 2x 3phase generator/motors), two energy sources and two high power inverters and a lot of bracketry to tie it all together in in place of one ICE... I know they can go pop unexpectedly but which of those two options sounds more likely to develop gremlins and realistically, which is going to be heavier :(

Personally speaking as as a glider pilot and an electronic engineer, given your stated goals I'd go for a nice standard 'off the shelf' self launching motorglider if it's the flying you're interested in. Second choice, with a much bigger budget and pretty well purely for the pleasure in the project and for quiet flight I'd go for an electric conversion on an existing self launching motorglider. Sell the ICE to pay for some bits. Seems like an expensive option to me but then I think the regulatory environment is a little different over there. A battery fire would be my main concern, pretty much every other powertrain failure in an SLMG you'll walk away from.
i typed a great response but i swear this thing signs me out and erases whatever i have written...

i pretty much said- when people make it sound like such a draggg of a swap it loses it's allure lol.
Its really just an electric vehicle with a compact high output onboard generator that weighs only 70lbs more then the vehicle would in its solely electric form

24lb engine+ 24 pound generator +11 pound controller + 11 pounds of misc.

and electric planes are already flying in this ballpark flight time wise, if not farther (this is info from 07-08,first attempts ) - http://www.aeroconversions.com/e-flight/images/Endurance_Chart_2.jpg

Since your a gliding pilot and engineer i was wondering what your thoughts were on the Xenos by sonex and the Europa Xp with Glider/Long Wings? they both get 40-45+mpg on their best "economy" behavior and both sport engine out landing abilities. They also seemingly stay in theme within your electric self launch motor glider params
 

·
Registered
Joined
·
571 Posts
I wouldn't make a hybrid airplane, let alone series hybrid.

Hybrid is best when the required power levels vary a lot in driving, including negative values (braking) and zero (idling). This means city driving in a car.

AFAIK, you keep relatively high and constant power levels (at good rpm range) all the time when flying so the ICE is relatively efficient. But the real reason you use an ICE in a plane is the energy density of fuel vs. energy density of batteries. Any hybridization will make this only worse.

Maybe a parallel hybrid with a small battery pack that would supply some extra power when briefly needed (takeoff?), but I cannot see series hybrid doing any good in this application.

As I have stated before, series hybrid works for cars as a range anxiety remover device by allowing longer trips every now and then, combined with a long full-electric range normally used.
 

·
Registered
Joined
·
74 Posts
Since your a gliding pilot and engineer i was wondering what your thoughts were on the Xenos by sonex and the Europa Xp with Glider/Long Wings? they both get 40-45+mpg on their best "economy" behavior and both sport engine out landing abilities. They also seemingly stay in theme within your electric self launch motor glider params
I'm not familiar with them to be honest, I only fly pure gliders and nobody at my club has either aircraft type. Interestingly, and I wasn't aware of this before so thanks for piquing my interest, the Europa is made just up the road from where I live.

Looking at those fuel consumption figures and doing some back of an envelope calculations it looks like you'll need something like 25-30kWH of battery for a 100mi flight, less if you get into some lift, more if you get into trouble plus a bit in reserve of course however far you choose to fly.

That's going to be roughly 20x the weight of the equivalent petrol at 200+Kg for a 30kWH pack which is going to seriously impact on performance even if it doesn't take you out of limits for the airframe. You also may not achieve the stated airframe efficiency at the upper weight limit, you'll be a lot draggier. You could probably do it as a single seater but that doesn't sound like a compromise worth making to me.

I think to make touring practical you probably need to look at something slower still that can cruise at nearer 80mpg than 40. Of course the beauty of an SLMG is that in good conditions they will fly engine off but that's not a great deal of help if you don't get good gliding conditions or are not into that type of flying.

Discovery channel did a series on building a Europa a few years back: 'An Aircraft is Born' I think it was called. Might be of interest.

Good luck with it, whichever way you go but I do think you're going to find it very difficult to develop a satisfactory solution. A roughly 30kW + 30kW parallel hybrid looks to me to have the most promise of the 'electrical' solutions for a practical aircraft but being hard nosed about it the standard engine is the better choice.

jk
 
1 - 20 of 40 Posts
Top