# Aircraft conversion



## HydronCollider (Nov 15, 2010)

Hey magnum, I probably shouldnt even be replying to this as I have no qualifications or experience but its an awesome project. Ive heard of a light weight using this controller before
http://kellycontroller.com/khb1240124-120v400aopto-bldc-controllerwith-regen-p-929.html
look on the kelly controller main page under "ev show" and wait for the scrolling vehicles, 2 aircraft will scroll by that use that contoller. 

The main thing I would be concerned about is the motor duty. I dont think that most motors used on this site could handle a constant 3000 rpm duty, hopefully someone with more experience will chime in on that.

good luck!!


----------



## mizlplix (May 1, 2011)

Welcome to the forum. I am sure you will get a ton of Excellent help with your project. These people have "been there, done that" with most every component in an EV. Some are (or have been) in the electrical industry too, as engineers, designers or technicians.

Could you give some requirements?

Like:

HP- maybe a HP/torque curve you need to see based on the propeller you envision using. that will get things moving.

BTW: I foresee an issue with the Motor/generator deal.....weight. 

"I want to run off a diesel generator with veggie oil conversion with battery as a backup or switched on for in flight for short periods but mainly as a back up for generator failure."

You are talking a hybrid rather than a purely electric craft. They always will be more complicated and difficult. 

There are threads dealing with a "Booster" trailer set up for an electric car. They allow you to hitch up a gen set on a trailer to the electric car to get some serious highway range out of them. Read all you can find. Google is your friend.

I look forward to helping you when possible.

Miz


----------



## magnum (Aug 23, 2011)

Thanks guys! I'm still working on the initial needs for torque etc to get it off the runway and when I find some numbers I'll post them up.
My understanding from reading here is that this is a "series hybrid". I'm flexible about running off the generator only but that is what I would "like"  Hopefully the battery technology will break through to something lighter soon!
Also, I understand about the weight of the generator and hopefully I can find a compromise for this as well as remove all the weight from everything I can as its installed.
Chevy has a new electric plane design, (with a French company I think) like this that uses a 1 rotor Wankel engine generator with a battery setup so I know I'm on the right track. Its just finding a combination that's the right fit for what I'm doing is what I'm after. 
Thanks!


----------



## shock (Jul 16, 2011)

Hi, Magnum

I am also a "junior member" here but I am a pilot and aircraft owner. (Mooney M20E). I am obviously a speed junkie, owning a Mooney and upgrading a porsche to compete with a Tesla roadster. Are you considering modifying an existing airframe? If so please post details, it will help with power plant. I also hold level 3 hang glider cert. My aircraft is IO360 200HP to drive a small plane. I have not heard of anything less than 60HP with glider-class aircraft. (but I certainly have not heard of everything.) Name your needed HP and max weight and the gurus on this forum may be able to expand to aviation with motor/controller/batteries that can match your requirements purely on weight. (Challenge time, guys!) 

Watching the replies with interest! Time to offer your opinion in my world now, lol!

Doug


----------



## DavidDymaxion (Dec 1, 2008)

Magnum: Sounds like a challenging but great project!

If you are going DC, your "second controller" could be as simple as a contactor that switches the motor full on. Generally it is not good to switch a contactor under load, but in this case that could be a better alternative to crashing! Whatever takes out controller 1 might also take out controller 2, so the robust simplicity of a contactor would be nice.

You are going to have to watch for motor overheating. Most cars run at low power with very short bursts of high power. An airplane runs at high power most of a flight.

Shock: I'm also building a performance EV Porsche, and hope to take Teslas... in first gear anyway, and eventually top speed. They'll probably always toast me in the ~40 to 125 mph range. Do you have any pics of your machine online? I'd love to see them. You can see some pics of my car at http://ExplodingDinosaurs.com . Here's a fun idea, we should race the airplane.


----------



## mizlplix (May 1, 2011)

True, in an aircraft, the power plant usually runs at a higher power requirement than in an automobile. (But they do share some commonalities). 

100% power for take off, 80%-90% for climb, cruise (based on altitude/loaded weight) 50%-70%. 

Over heating....Remember, aircraft have the advantage of prop wash and ducting to help with motor cooling (internal and external). I would have the motor frame replaced with an aluminum housing, (incorporating the motor mount possibly) for weight and better cooling.

In my world, The perfect electric plane would have a series/parallel system. Series for high voltages on take off and switch to parallel for cruise. OK, Maybe a stretch, but just dreaming. Maybe a series/compound switchable field motor would work better?

Batteries, I like the lithium pouch cells for weight/power factor. You get rid of a ton of plastic....

AC has the advantage of no brushes and a broader RPM range as well as it is easily switch reversible for landings (woohoo). But has a a limited selection currently.

DC has torque, possibly a switchable field configuration and the added safety of the above mentioned contactor emergency over ride in case of controller failure. They also run in the RPM range he indicated above.



Sorry to ramble, but sometimes you need to let out those random ideas or your head will explode. Miz


----------



## piotrsko (Dec 9, 2007)

my series of $.02:

EAA has been doing many articles regarding "the NEW wave" of electric powered flight. they have ultralights through 182 class craft in design using anything from hybrid technology to full blown all electric packs.

Lowest I've seen is 6 hp on a ultrafright flying lawn chair. (no that ain't the kit name)


----------



## magnum (Aug 23, 2011)

Thanks for the response guys!!! The cooling will not be an issue as I plan on naca ducts and a thermostat controlled fan to cool the motor. Plus, at altitude its a lot colder air and it should be no problem keeping it real cool.
As far as the plane itself, it will be a flying wing with a high aspect ratio and very little drag CD. It will be very easy to push through the air thus less power drain at altitude.
I have a CNC guy who is going to cut / hot wire all the parts out of structural foam with his machine and therefore keeping the gross weight as low as possible. All parts will be vacuum bagged and it will be as light as I can make it.
All the spars and main structural parts will be laid up with a new material called Graphite 
http://www.marskeaircraft.com/carbonrod.html
and its 4 times stronger than aluminum and is really easy to work with and about a third of the weight of old style roving layups also. Amazing product!!!
The idea of changing the motor parts out for lighter aluminum or carbon fiber is just what I'm looking for so keep em coming guys.
PM me if you can help with the design. First thing I need is the correct motor as when I get the main fuselage made, I'll need to make the mounts next while its easy to get to.
Thanks again!!!!!


----------



## Ektus (Feb 15, 2011)

For weight saving and mechanical backup, I'd rather propose going parallel hybrid. Diesel engine, coupler, electric motor that doubles as generator, prop. Disengage the coupler to fly electric or in case of engine failure, use both ICE and electrical motor for take-off, use either one for cruising. That way, you can use a smaller size electric motor and a relatively small diesel engine, as neither has to deliver take off power alone. This would also eliminate the need for a backup controller.

What about regulations? Are there diesel engines with flight approbation? Is something like the Zoche Diesel in production? Otherwise, some small automotive diesel engine might work.

What about temperature? Vegetable oil will freeze very quickly if not properly insulated and/or heated, and that includes the fuel lines and filter.

Just my €0,02, I've got nothing to do with aeorospace apart from the occasional business flight as a passenger 


Regards
Ektus.


----------



## magnum (Aug 23, 2011)

Ektus,
Thanks for the response. The plane will be in the "experimental" category thus I can use/ build whatever I want for an engine etc.
As for the diesel, they are not preferred as a power source for this rpm range. I have read a lot about this in other forums as well as the rotary guys threads and bottom line, electric is the future and when the battery weight issue and longevity is advanced, aviation will be back to a person able to afford it better. Av gas is $4 to 5 dollars a gallon now 
I see your point about using both drives and I may consider that if it can be designed as fool proof and not complicated. Its not like I can pull over and get out and fix it if it fails. "KISS" is king in the air!  Plus its more weight to move.
Thanks!
Magnum


----------



## Ektus (Feb 15, 2011)

Small diesel engines should be running very well at 3000RPM. No reduction gear needed. With a parallel hybrid as suggested, you save on weight compared to a serial hybrid, as you do need only one electric motor (that doubles as generator) and not two of them. And only one controller, the backup being the mechanical drive from the diesel engine.

The motor in the serial setup would have to be able to deliver take-off power, and the generator cruise power. Then you would need a total of three controllers: One to operate your motor, one backup, and the third to govern charging of your battery pack. KISS sounds differently 

I dont know exact numbers, but I'd just make a list of all of the components needed for both variants and simply compare the weight sums.

For the serial setup, all weights wild guess:

AC Motor 100kW 100kg
AC Generator 75kW 80kg
Diesel Engine 75kW 150kg
3x Controller 3x 10kg = 30kg
Battery pack 150kg
Wiring, frames etc. 100kg
------------------------
Total dry weight for components: 610kg
That would be more than the total weight of your plane.

Now let's see what happens with the parallel setup:

AC Motor 75kW 80kg
Diesel engine 75kW 150kg
1x Controller 10kg
Battery pack 150kg
Drive shaft, clutch: 30kg
Wiring, frames etc. 90kg
------------------------
Total dry weight for components: 510kg

still a lot of weight, but 1/6th less than with the serial setup.

Your mileage may vary.


Regards
Ektus.


----------



## magnum (Aug 23, 2011)

Interesting. Weight, like you said is the big problem with these scenarios, but this is the discussion I am after. Thanks for this and keep it coming. 
There is a place that makes aluminum parts to make an approx 120lb Mazda rotary engine to run on gas but you still need a reduction gearbox box, but it would still be less weight. 
Are you saying that the combination would be like this? Engine w/ clutch connected to electric motor on one end and to the drive shaft on the other and then to the prop?
Thanks again!!!
Magnum


----------



## DavidDymaxion (Dec 1, 2008)

The iron housing provides a magnetic flux path. One drag racer thought he'd save some weight and shaved down the outer case -- his drag racer went slower! So unfortunately it won't work well to get a motor designed for iron and replace that with aluminum.


mizlplix said:


> ... I would have the motor frame replaced with an aluminum housing, (incorporating the motor mount possibly) for weight and better cooling. ...


----------



## Ektus (Feb 15, 2011)

magnum said:


> Are you saying that the combination would be like this? Engine w/ clutch connected to electric motor on one end and to the drive shaft on the other and then to the prop?


Yes, that's the idea. With the clutch, you can disengage the engine. But there's a mechanical connection between engine and prop, so you can also fly with the engine alone. 

In cruise mode, you would use the diesel engine and simultaneously slowly charge your battery, using the motor and controller as a generator (regen function in street vehicles).

In case of engine failure, disengage the clutch and fly electric. This mode is also viable for normal cruising as long as there's enough juice in the batteries.

In case of controller or battery failure, disengage your main contactor and fly with the diesel engine alone as always.

For take-off or racing, both drives would deliver power.


Regards
Ektus


----------



## Duncan (Dec 8, 2008)

Hi Magnum

_As far as the plane itself, it will be a flying wing with a high aspect ratio and very little drag CD. It will be very easy to push through the air thus less power drain at altitude._

You are aware that a flying wing still needs a tail and that a short moment arm on the tail means increased drag - there are reasons why the "conventional" layout is so popular, even Burt Rutan eventually went conventional - especially for his high efficiency designs


----------



## magnum (Aug 23, 2011)

Duncan said:


> Hi Magnum
> You are aware that a flying wing still needs a tail and that a short moment arm on the tail means increased drag - there are reasons why the "conventional" layout is so popular, even Burt Rutan eventually went conventional - especially for his high efficiency designs


 Don't know where you get this. There have been several true flying wing designs that have flown and done so very well. Here is one for example. http://www.twitt.org/DavisWing.html and I can send you more.
The reason Rutan went to the canard design was so the average pilot could build and fly it with a great deal of safety built into the design. I started building one my self a while back and sold it in favor of going in this direction. I have an engineer helping with this also. 
Really don't want to get off topic here. My main need is for help for the propulsion design. Please chime in if you are experienced.
Thanks
Magnum


----------



## GizmoEV (Nov 28, 2009)

Ektus said:


> For the serial setup, all weights wild guess:
> 
> AC Motor 100kW 100kg
> AC Generator 75kW 80kg
> ...


Why 3 controllers? Each controller can do power and regen so the third one isn't needed unless you want the extra redundancy.


----------



## Ektus (Feb 15, 2011)

GizmoEV said:


> Why 3 controllers? Each controller can do power and regen so the third one isn't needed unless you want the extra redundancy.


The extra redundancy was part of the question in post #1:


magnum said:


> I will also need dual controllers for redundancy in flight for safety so that I can switch over in case one fries.


In case of a serial hybrid, there are more single points of failure, whereas the parallel hybrid has a certain degree of redundancy already built-in.

Regards
Ektus.


----------



## Ektus (Feb 15, 2011)

magnum said:


> Really don't want to get off topic here. My main need is for help for the propulsion design.


Well, there are a lot of decisions to be made:

- Prerequisites like size, weight, power needed, mass allowed due to regulatory restrictions

- Topology of setup (parallel, serial, mixed, ICE only, electric only)

- Power needed for the components

- System evaluation, failure mode analysis, cost efficiency, fun factor 

Then you need to find the right components, e.g. diesel engine, electrical motor and controller, assorted user interface elements, battery chemistry...


I'd look into the new (well, 2007) 2.0l diesel boxer from subaru. That could be a lightweight possibility for your ICE.

For motors, there are plenty manufacturers for industrial applications, but those tend to be rather heavy as they are made for decades of heavy duty use. The same goes for controllers.

Well, that's just scratching the very beginning. You've got a very interesting project there 


Regards
Ektus.


----------



## GizmoEV (Nov 28, 2009)

Ektus said:


> The extra redundancy was part of the question in post #1:


Right, that is why only 2 are needed. If redundancy wasn't needed then only one controller would be needed. Earlier in the same post you said:



Ektus said:


> The motor in the serial setup would have to be able to deliver take-off power, and the generator cruise power. Then you would need a total of three controllers: One to operate your motor, one backup, and the third to govern charging of your battery pack. KISS sounds differently


You don't need the third to govern the charging of the battery pack. The controller is programmed not to overcharge the battery pack during charging (regen).


----------



## Ektus (Feb 15, 2011)

GizmoEV said:


> You don't need the third to govern the charging of the battery pack. The controller is programmed not to overcharge the battery pack during charging (regen).


Except it's not exactly regen. It's a serial hybrid. I'd better say the third controller is the onboard charger. But it's a quick charger that has to deliver full system power!

Power flows: 


```
[FONT=Courier New]ICE-generator-charger-+-controller-motor-prop
                      |
                      +-battery[/FONT]
```
To get some redundancy with this setup, you can disconnect the battery with a couple switches, and you could even bypass the charger and the controller by connecting motor and generator directly. But that's also a lot of high power switches and thick cables.


Regards
Ektus.


----------



## magnum (Aug 23, 2011)

Ektus said:


> Well, there are a lot of decisions to be made:
> 
> - Prerequisites like size, weight, power needed, mass allowed due to regulatory restrictions
> 
> ...


!!!!!!!!!!!!!!!!!!!!!!!!!!!!


----------



## GizmoEV (Nov 28, 2009)

Ektus said:


> Except it's not exactly regen. It's a serial hybrid. I'd better say the third controller is the onboard charger. But it's a quick charger that has to deliver full system power!
> 
> Power flows:
> 
> ...


Then do away with the AC generator and get a DC generator to hook directly to the batteries, and hence the motor. You eliminate the weight, efficiency loss, and failure point of the charger. The problem with connecting directly with the motor, bypassing the controller, is that if the motor is not a DC motor but an AC Induction motor it won't turn with the controller bypassed.

It might be best to narrow down the motor types by comparing the power to weight ratio of several options. Series DC has the torque and can handle direct-drive prop speeds, can be directly connected to the batteries for full power but doesn't have any regen capabilities. When reading about a small AC powered airplane they said that they could get, IIRC, over 20 minutes of flight back just from regen coming down from altitude.


----------



## magnum (Aug 23, 2011)

GizmoEV said:


> Then do away with the AC generator and get a DC generator to hook directly to the batteries, and hence the motor. You eliminate the weight, efficiency loss, and failure point of the charger. The problem with connecting directly with the motor, bypassing the controller, is that if the motor is not a DC motor but an AC Induction motor it won't turn with the controller bypassed.
> 
> It might be best to narrow down the motor types by comparing the power to weight ratio of several options. Series DC has the torque and can handle direct-drive prop speeds, can be directly connected to the batteries for full power but doesn't have any regen capabilities. When reading about a small AC powered airplane they said that they could get, IIRC, over 20 minutes of flight back just from regen coming down from altitude.


Sounds like what I'm after. All of the electric plane articles use DC. I started this thread in the forklift thread and it was made into a separate thread. Point is, the traction motors tough and can take the environment except they are way heavy. There is a couple of places here I can get a rebuilt one from if we can figure out which one willl work.
Thanks
Magnum


----------



## mizlplix (May 1, 2011)

Mag: When I read the words "Flying Wing" I immediately thought...Pusher.

Is this going to be a pusher design? It makes a big difference.

Single large motor along the center-line, or two smaller motors in the wings?

Just for the record, I am partial to an ALL Electric craft.

Look up "pouch cells" Some of the drag guys are using them. You can put them anywhere, wings, external detachable pods, every little unused space can be filled. 

I'm thinking DC because DC motors run in the RPM range he mentioned previously. The extra RPM range AC allows might not work with most prop designs without a reduction gear. And DC can be made to regen too if necessary.

NOTE: I didnt even give magnetic flux a thought when I suggested making the motor housing of Aluminum. That goes for Composites too. Carrumba!


----------



## magnum (Aug 23, 2011)

mizlplix said:


> Mag: When I read the words "Flying Wing" I immediately thought...Pusher.
> 
> Is this going to be a pusher design? It makes a big difference.
> 
> ...


****** Not a problem as that's why we / I am here!!! 

Thanks
Magnum


----------



## kerrymann (Feb 17, 2011)

Very interesting project idea. From the sounds of it you are building your own airframe and doing a EV powerplant. I would highly recommend you do one or the other. Not to be a nay sayer but trying to develop both means that the chances of success are greatly reduced (unless you have a high six figure budget). I would take an available airframe like a LSA or another kit and concentrate your efforts on the powerplant. What are your goals for the plane? Seats? Gross weight? Useful load? Range? Speed? Altitude? A lot of questions but the answers are really key to your project.

The flying wing is the ideal for high efficiency flight. Plank flying wings (like Jim Marske's designs) have the advantage of easy of construction but don't offer a lot of volume for batteries. A **** Delta might a starting point for an airframe that still has good volume for batteries Electric will make the flying wing "easier" because you will have great control over CG and not need a lot of trim like you would with burning fuel.

"The weight/volume of your pack is something your going to have pick now." It will have huge effect on the viability of the aircraft and needs to be "picked" from the start for weight CG and volume reasons. Is there a particular battery technology that you anticipate being available in 2 years? 

I don't understand brushless for fire reasons but as long as the motor is not in a possible vapor zone the brushes should not pose a fire hazard.

150hp is going to be a tall order for almost all motors. Even at high airspeeds cooling will be an issue for that kind of continuous power. The air is cooler at higher altitudes but it is also much thinner and the resulting cooling drag will be large. Not to mention a pack that will be able to supply that kind of power while on climb out. I am assuming that mutli engine is out of the question?
You will definitely need a water cooled controller but there are several options that would work. I think a Soliton would be your best bet because they are rated at 600/1000amps indefinitely with proper water cooling.

I definitely second EAA as this has been a popular topic recently. I am a kit builder myself and before I went into solar I was a structures engineer doing composite 6-8 seat props and jets, FAA DER, etc and I would be glad to lend help anyway I can. 
Can't wait to hear more,


----------



## magnum (Aug 23, 2011)

kerrymann said:


> Very interesting project idea. From the sounds of it you are building your own airframe and doing a EV powerplant. I would highly recommend you do one or the other. Not to be a nay sayer but trying to develop both means that the chances of success are greatly reduced (unless you have a high six figure budget). I would take an available airframe like a LSA or another kit and concentrate your efforts on the powerplant. What are your goals for the plane? Seats? Gross weight? Useful load? Range? Speed? Altitude? A lot of questions but the answers are really key to your project.
> 
> 
> ****** I understand your point but this is what I want and I feel its the best airframe for what I want to do. As far as needs my goals are light weight, 2 seats with a 4 hour flight time and at least 200MPH. I basically want a cross country hot rod that nobody else has and I can taxi "past" the gas pumps.
> ...


PM me and we'll talk further. You may be the person I am looking for for structural guidance on this project. I have experience in composites from past projects and it would be nice to have someone to lean on.
Thanks 
Magnum


----------



## GizmoEV (Nov 28, 2009)

magnum,

It will be easier if you separate the quotes from your responses. When you quote just add a *[* followed by */quote]* at the end of the first part of the quote and then write your response. After that, just highlight the next part of the quote and click the cartoon bubble icon in the tool bar and it will automatically put quote tags around the next part and so on. That will make it much easier to read.

I haven't quite figured out the multi-quote button yet so that might be the thing to use. Maybe someone else will chime in on it.


----------



## magnum (Aug 23, 2011)

OK, I'll try to do that. I didn't think about it, that's why I put the stars in my response
Thanks
Magnum


----------



## mizlplix (May 1, 2011)

Prop-----------------electric-coupler-ice. (Front of craft)





This would give you both power plants for take off/ climb.
Ice alone for cruising - elect. Just turned off and free wheels.
or ice and elect in regen/ charge batteries in cruise.
Or electric for cruising- ice uncoupled.
Or electric in regen. - ice uncoupled when going to a lower alt.

Wouldn't a controllable prop be cool? (or even reversible)

Miz.


----------



## magnum (Aug 23, 2011)

Thanks for the input but with this airfoil, it wont fly with the prop in front. It disturbs the boundary layer and control surfaces.
I think I am going to have to use DC with a DC generator to make this work. AT least that's where I am at this moment!


----------



## mizlplix (May 1, 2011)

Excuse me but I put (front of craft) opposite end from the propeller indicating a pusher, like viewing from the right side.


Just trying to eliminate the extra generator and associated weight.

Of coarse my aircraft experience is with old war birds, so it pretty ancient.


Miz


----------



## magnum (Aug 23, 2011)

OPPS!! Sorry, it hit the gray matter backwards when I looked at it. This might work if I can find the right ICE. I am looking into it. Hopefully I can get this sorted out in the next few week and start looking for the parts
Thanks
Magnum


----------



## GizmoEV (Nov 28, 2009)

I seem to remember seeing a wide cogged belt coupling an ICE and Propeller on some aircraft somewhere. If everything in line were too long and you could mount things side by side then coupling to the same shaft with a cog belt might be an option where the clutch is between the ICE and the pulley to the prop shaft.


----------



## magnum (Aug 23, 2011)

Been researching all evening and I found a small gas turbine 85HP engine that may be perfect. It weighs 60lbs!!!!! I have e mails out to get more info. Turbine to centrifugal clutch to motor to prop.


----------



## bruceme (Dec 10, 2008)

I have a gas Alisport Silent-IN self launch glider that I want to convert to electric. Thinking ~3kwh of TS and a 30kw BLDC motor.


----------



## magnum (Aug 23, 2011)

Sounds like an interesting project! Keep us posted on it.
Magnum


----------



## jk1981 (Nov 12, 2010)

There are some good looking pancake style electric motors available (AC with matched inverter) that are designed for self launching/sustaining gliders http://www.enstroj.si/Electric-products/emrax-motors.html that might be worth a look. They appear to be light, powerful and built for the job.

Maybe a motor coupled via a freewheel bearing or clutch in parallel with a small aircooled engine (so you automatically disengage/unload the ICE until it is up to motor/hub speed and when it's not running)?

Prop - AC motor - Clutch - ICE

It may be possible to apply drive through the center one of those pancake style motors (appropriately modified), if not you'd need to belt drive from one power source or the other (or both) to the main output shaft. Either way you'd have a pretty light compact drive that you could tailor to fit the available space.

With a small inline/flat twin and the motor running you'd have your required takeoff power and potentially the ability to cruise on either. An off the shelf inverter with properly set up regen braking would suffice for controlling the motor and top-up charging the pack. Being a multipole permanent magnet unit the cogging torque and parasitic drag in the motor will be low while ever the inverter is not applying a braking load (the no-charge cruise condition running on ICE).

The battery is another issue, LiPO is light and has exceptional power density, easily enough to provide takeoff power at a very reasonable pack weight/volume for a small lightweight aircraft. However the energy density isn't great, the longevity and quality is a concern and I don't I'm not convinced I'd want to be flying with them unless I were wearing a chute!

Even with a relatively simple set-up like that I've suggested adding the complexity of an ICE or electric drive is likely to result in a heavier, less reliable powerplant requiring more maintenance than if you simply plumped for an appropriately sized one of either type ICE or electric.

Presumably you're thinking of using some kind of automatically feathering prop to control load and maintain a relatively constant RPM?

jk


----------



## magnum (Aug 23, 2011)

> There are some good looking pancake style electric motors available (AC with matched inverter) that are designed for self launching/sustaining gliders http://www.enstroj.si/Electric-produ...ax-motors.html that might be worth a look. They appear to be light, powerful and built for the job


.

Thanks, I had not seen this yet. Sounds like an option.

''Maybe a motor coupled via a freewheel bearing or clutch in parallel with a small air cooled engine (so you automatically disengage/unload the ICE until it is up to motor/hub speed and when it's not running)?''


Prop - AC motor - Clutch - ICE This is what I have come to, to make it work. I have been looking into the small gas turbine for the ICE with a shaft drive on it like the Solent which has about 80HP and burns about anything for fuel. It would be use for lift off and then go to batteries for flight. It can also be used to charge with.
Connect it with a centrifugal clutch or an in an out drive box to the DC motor and back to the prop. There are a lot of aircraft APU units that mount inside the plane itself and are altitude rated and there are a lot of the out there that will work. Priced pretty well also! It would only be run for short periods of time and this would save the drain on the batteries

''It may be possible to apply drive through the center one of those pancake style motors (appropriately modified), if not you'd need to belt drive from one power source or the other (or both) to the main output shaft. Either way you'd have a pretty light compact drive that you could tailor to fit the available space.They say on the site it can be modified. 
With a small inline/flat twin and the motor running you'd have your required takeoff power and potentially the ability to cruise on either. An off the shelf inverter with properly set up regen braking would suffice for controlling the motor and top-up charging the pack. Being a multipole permanent magnet unit the cogging torque and parasitic drag in the motor will be low while ever the inverter is not applying a braking load (the no-charge cruise condition running on ICE).'' I think this could be made to work out well. With this setup, it will give me almost 200HP for take off with both the turbine and the motor.

''The battery is another issue, LiPO is light and has exceptional power density, easily enough to provide takeoff power at a very reasonable pack weight/volume for a small lightweight aircraft. However the energy density isn't great, the longevity and quality is a concern and I don't I'm not convinced I'd want to be flying with them unless I were wearing a chute!''I know, batteries seem to be the big headache for now. This is why I am building redundancy into this project as if one fails I at least have another chance to get down safely. Not many GA's have that option.
I have been reading about the pouch batteries and they might be an option as I have generating and also re gen going for me. If they can recharge quickly, I can switch back and forth and stay in the air for longer. I want to shoot for a 3 to 4 hour trip.


''Even with a relatively simple set-up like that I've suggested adding the complexity of an ICE or electric drive is likely to result in a heavier, less reliable power plant requiring more maintenance than if you simply plumped for an appropriately sized one of either type ICE or electric.''



I don't know about this yet. I have seen a few gas turbine set ups in home built's and from what I have seen so far, I can make a connection to the electric motor fairly easy, but probably not cheap  I know this is one area I will need a competent engineer to help with the design and diagnosis for problems with proper in and out and switching from one to the other with out having harmonics and outright drive line failure

''Presumably you're thinking of using some kind of automatically feathering prop to control load and maintain a relatively constant RPM?''


This is something I am not familiar with yet and will get into it more after I have some of the main parts figured out so when I speak with someone on it I will have parts in hand so to speak and can give all the information to them so they know what is what. Definitely will need engineering on this crucial part.
I think so far the best option is the small gas turbine for light weight, 80#'s and then to a clutch or gear box and then to a light weight motor such as in the link you provide above. 
Will need RPM for all 3 to see whats going on at a glance. Its starting to look better on paper at least!!!! 
Thanks for your time and chime in any time if you think of anything else that may help.
Magnum


----------



## magnum (Aug 23, 2011)

Found an off the shelf clutch assembly that is used on Rotorway copters with the gas turbine conversion and it will work perfectly with my combination.
Now all I need to figure out is the correct motor and battery combination and I think I'm there!
Magnum


----------



## magnum (Aug 23, 2011)

Frodus,


Sent you a PM


----------



## frodus (Apr 12, 2008)

Tom, Replied!


----------



## magnum (Aug 23, 2011)

The project is slowly coming together. I am getting a "brain trust" in place for consulting for everything I need and I hope to pull the trigger about Nov 1 to start getting foam cut and parts coming my way!!!!!!!


Magnum


----------

