Mini generator/alternator

[Orbital]

Hey all.

I'm in the midst of a project with a bunch of people from school. We are building a UAV for a contest over the summer. One of my friends and I are looking at putting together a generator/alternator (whatever you would like to call it) and I was hoping to run my idea past everyone that seems to know a whole lot more than I do.

So here is what I need.
150W to run everything that I need (looking to run atleast 50 or 60% saftey on the system)
I'm just going to start it up when its at crusing altitude @5000RPM.


My plan was to run 2 motors (both capable of running the system, in case something happened to one of them...)

something like THIS (http://www.xheli.com/el4003inbrmo.html)

Add a pinion gear to the ends of the motor and run a sprocket and belt from the "drive shaft" (I am not sure if that's the correct technical term or not but I hope it gets the point through) from there run the lines to a 3 phase rectifier (so I have DC) and then from there it would allow me to put a trickle charger to my battery and run my electronics.

I've got an e-mail into Sullivan about putting together something that I could use, but I cant wait for them, time is going to be tight.


So what does everyone think?

I didnt see any threads that were still active on this topic, I hope I didnt miss something important....

[small_rcer]

You can buy an off the shelf alternator from here

http://www.sullivanuav.com/home.html

[airmcn_3]

You can buy an off the shelf alternator from here

http://www.sullivanuav.com/home.html


Nice find!

[patrickegan]

The reg’s change for aircraft that generate their own power.

[airmcn_3]

The reg’s change for aircraft that generate their own power.

Patrickegan,

Since you are on top of all of us in regards to regulations why don’t you please advise........

There are much more professional ways to get your point across; you come across as rude and ready to pounce on any individual that has a question or comment, kinda like a big cat hunting its prey.

I am not trying to make enemy's here but you are doing one hell of a job to make people want to say nothing but bad about you.

Instead of just saying simple one line statements why don’t you share the knowledge you have about these regulations? This is a forum afterall.

Chris

[patrickegan]

The FAR says something to affect that when a aircraft generates power it has to carry position reporting equipment (don’t have time to look it up). Said equipment is certified (expensive), and heavy (payload penalty), not trying to be snarky, just trying tell people about potential legal pitfalls of operating unmanned aircraft. Sorry if that comes across as rude :)

[airmcn_3]

The FAR says something to affect that when a aircraft generates power it has to carry position reporting equipment (don’t have time to look it up). Said equipment is certified (expensive), and heavy (payload penalty), not trying to be snarky, just trying tell people about potential legal pitfalls of operating unmanned aircraft. Sorry if that comes across as rude :)


Patrickegan,

Not a problem and thank you for taking the time to give a brief explanation. In regards to the position reporting equipment, couldn’t it be something that relays GPS waypoint position similar to our GS software, this would help eliminate the weight penalty.

You are doing a great job letting us know of the current rules and regulations and I would prefer if you did not stop doing so. The rules are what we have to live by if we want to pursue this hobby/business.

I personally do not have an issue with you and I apologize if I may have come across too blunt. You have a vast amount of knowledge about the rules; we all just want to know with some explanation. At least most of us.

Cheers,

Chris

[patrickegan]

It will be up to the community to band together and follow the rules (or make new one), or this industry will be stifled. We are being led around by the whim of the vendors and regulators.

Position reporting i.e TCAS

[airmcn_3]

It will be up to the community to band together and follow the rules (or make new one), or this industry will be stifled. We are being led around by the whim of the vendors and regulators.

Position reporting i.e TCAS


Yes I would have to agree. Thank you for the TCAS info.

Chris

[patrickegan]

If people want to say bad things about me because I speak about rules and realities of being an airspace user, I have no control. There are rules of the air, if we launch something in the air we have to follow the rules or be viewed as a menace. Not trying to be a kill joy, just want to see the industry have a chance at being an industry :)

[DaveAtDigital]

I get what patrickegan’s saying. One injury, one screw up by a UAV hobbyist can set the whole industry back a decade.

Many people want to fly farther/higher than legally permitted …fpv and radio technology is making this a safe possibility….and we should be able to legally pursue our craft. Unfortunately, the fact of the matter is, if you’re getting into UAV’s, plan on living outside of the law a little bit.

-Dave

Also, GREAT find!


You can buy an off the shelf alternator from here

http://www.sullivanuav.com/home.html

[spitfiremk9]

If people want to say bad things about me because I speak about rules and realities of being an airspace user, I have no control. There are rules of the air, if we launch something in the air we have to follow the rules or be viewed as a menace. Not trying to be a kill joy, just want to see the industry have a chance at being an industry :)

Patrick

I dont think people want to say anything bad about you, personaly there is nothing bad that anyone can say, but I have noticed your one-liners, which are quite deeply humoured and I dont think Aircmn meant what he said in a derogatory fasion, I got the impression that he was probably a little frustrated to begin with and trying to say what you feel through a keyboard is nigh on impossible, this forum needs input like yours.

[fnev]

Could we merge this tread with the FAA regulation one as it is getting to the same can of worms???

Regarding alternators: do you know that a brushless motor is a hell of efficient alternator? You will need to rectify and regulate the output. Regarding the coupling: this is not as trivial as it may sound as the engine has a pulsing cycle. A belt driven system will shred belts in NO time mainly due to the heat generated in the belt by the pulsing load. Now, if the load is not too high for the design it might does the trick. A gear system is not simple either and now the pulsing load is transformed in a chock load… All of this before the regulations consideration: sometime something that seems simple ends as a very complex task, especially in an aeronautical environment.

[RolandS888]

I was considering the Sullivan generation gear a while back and got some prices....which made carrying extra LiPos a very viable option.

I have seen a brushless motor coupled to an OS 2 stroke and it doubled as a starter and alternator for power generation.

Have a look on youtube, there is a few different configurations of brushless motors being used for power generation on RC planes.

[Orbital]

You can buy an off the shelf alternator from here

http://www.sullivanuav.com/home.html


Thanks for the link, I had stumbled over that earlier and I personally did not see where I could buy one, or for that matter the price. I hear that they are quite expensive, so I sent Sullivan an e-mail asking about the price, hoping to hear back front them soon.

As for the need to have position equipment on board the plane, I am not exactly sure about that, I will look it up. I do know that all the nesessary equiptment to track the UVA is already in the plane (that primarly being the reason I need to put something into it to power it.) Also, weight plays not part in this competition, It doesnt matter how it looks, how heavy it is, or anything else asthetic for that matter, just that it completes the task.

How important is a regulator in the system? I know that I get 3 phase AC from the alternator/motor and then by running that through a full bridge restifier I can create DC in order to run everything.....but where exactly does the regulator fit into the system?


Thanks for everyone's help so far

[wonginator1221]

Excuse me for being rude or ignorant, but why would one install a generator on an electric aircraft. I was under the impressions that lenz's law prevents the system from being useful. Wouldn't it be better just to carry a larger battery with a high C rating?

[Orbital]

Excuse me for being rude or ignorant, but why would one install a generator on an electric aircraft. I was under the impressions that lenz's law prevents the system from being useful. Wouldn't it be better just to carry a larger battery with a high C rating?


Well my group wants to put a generator on our aircraft b/c we need about 120-150W of power so that we can run the systems that are going into the aircraft. The ammount of batteries (from what I am told) would be a lot, weight/size wise. By putting a generator on the airplane, this would allow us to take off, get to cruzing speed, turn on the generator and systems and complete the task.

As for lentz's law, it is talking about a back current, but that back current is not the same intensity of the original current. which means that the system will heat up a little bit and we will not have 100% efficency, but it will do what we need it to do. What I'm putting together is a lot like the alternator on your car. Did I explain that well enough for you?

[airmcn_3]

Patrick

I dont think people want to say anything bad about you, personaly there is nothing bad that anyone can say, but I have noticed your one-liners, which are quite deeply humoured and I dont think Aircmn meant what he said in a derogatory fasion, I got the impression that he was probably a little frustrated to begin with and trying to say what you feel through a keyboard is nigh on impossible, this forum needs input like yours.


You are correct, I was not trying to be derogatory just a little frustrated on the one line comments. Again I have no issues with Patrick, just making a comment I should have probably kept to myself. Too late now.....

Back to the generator!

Chris

[Mick Molloy]

http://www.youtube.com/watch?v=ot-El7mupsY

Here is a mates setup using as a starter, generator and power boost....

[lvspark]

some info on the same topic from runryder http://www.runryder.com/helicopter/t153250p1/

[patrickegan]

No problem, thats what the forums are for! :)

[spitfiremk9]

Well my group wants to put a generator on our aircraft b/c we need about 120-150W of power so that we can run the systems that are going into the aircraft. The ammount of batteries (from what I am told) would be a lot, weight/size wise. By putting a generator on the airplane, this would allow us to take off, get to cruzing speed, turn on the generator and systems and complete the task.

As for lentz's law, it is talking about a back current, but that back current is not the same intensity of the original current. which means that the system will heat up a little bit and we will not have 100% efficency, but it will do what we need it to do. What I'm putting together is a lot like the alternator on your car. Did I explain that well enough for you?

I also can not understand why you dont just take whatever power you need from your pack??! I have to agree with wonginator, your generator is going to consume MORE power than it puts out, It is a phisical law that you can not change, or am I also missing a something relevant?

[gkamysz]

There seems to be confusion. People think that this is an electric motor driven model. The original post says he contact Sullivan who makes generators to fit IC engines. 150W load is significant, and depending on how long it needs to run, a generator system is going to be lighter.

Greg

[Orbital]

Ok, I'll try to explain myself a little bit better. I need to run 4 or 5 pretty large systems, 2 computers, a camera, etc, for hopefully no more than 40 min, but figure an hour max at the competiton. I forget the exact engine that we are now using for the competition, but the smaller back up engine is a SAITO FA-300T, and the engine that we are just recently aquired is about 4hp. So I'm not worried about drawing off the engine.
Think about the alternator in your car, when the car starts, it starts off of battery juice. then when it gets up and going, it charges the battery with the juice from the alternator and powers all the systems in the car. I'm building off of the same principle.


The reason that I am looking into putting a generator into place is because it would take a lot of batteries to power these and honestly, we are starting to run a little short on space and it would be a PITA to put them in and still land in the CG range.
Now I cant do the computations off the top of my head but the weight of the batteries would almost be prohibitive. not to mention the fact that we would pretty much need to go out and buy all the batteries that we would need ($$$$$) as opposed to putting together a generator set up for like $100



P.S. I got an e-mail back from Sllivan and they are expensive guys, it would cost about $2500 for their cheapest system. So were going with the lab build project this time around

[Red-Rx7]

Ok, I'll try to explain myself a little bit better. I need to run 4 or 5 pretty large systems, 2 computers, a camera, etc, for hopefully no more than 40 min, but figure an hour max at the competiton. I forget the exact engine that we are now using for the competition, but the smaller back up engine is a SAITO FA-300T, and the engine that we are just recently aquired is about 4hp. So I'm not worried about drawing off the engine.
Think about the alternator in your car, when the car starts, it starts off of battery juice. then when it gets up and going, it charges the battery with the juice from the alternator and powers all the systems in the car. I'm building off of the same principle.


The reason that I am looking into putting a generator into place is because it would take a lot of batteries to power these and honestly, we are starting to run a little short on space and it would be a PITA to put them in and still land in the CG range.
Now I cant do the computations off the top of my head but the weight of the batteries would almost be prohibitive. not to mention the fact that we would pretty much need to go out and buy all the batteries that we would need ($$$$$) as opposed to putting together a generator set up for like $100



P.S. I got an e-mail back from Sllivan and they are expensive guys, it would cost about $2500 for their cheapest system. So were going with the lab build project this time around

I run an alternator system on my helicopters. I have a gas powered helicopter and a nitro powered (.50 size raptor). They work amazing. I never worry about having to charge the batteries. I have even had once issue with the battery switch coming disconnected inflight on my Raptor, but I was able to maintain like it never happened (because it was powered all the way through).

I think people were confused for they thought you were going to run an electric alternator setup off of another electric motor.

Anyhow, I recommend that you contact these two people:

Raja @ rbort@juno.com

or

Wolfgang @ Wolfgang@AirWolfRC.com

Either of them can make you something very reasonable for 5-10 times less than the price you are looking for.

[Orbital]

Red-Rx-7
Thanks for the info. My project just kinda got thrown on ice because of no one making a decision. I'm gunna keep pluggiing away. if anyone else has anything to add i'd love to hear it.

[dalbert02]

Try the cyber-flyer way!

http://www.cyber-flyer.com Look under 'helicopters'

http://www.cyber-flyer.com/heli/axi_gen_s.jpg

Electric generator
I've got many questions about this mod. It's a small brushless motor which is ran as generator. The voltage is converted to DC using 3-phase recitfier. And the output is then used to recharge Li-Poly battery pack and supply 10.0 v, 5.0A for operation of video transmitters and servos.
The "real" answer is that this is alien technology device which I stole from alien ship last year. It has enough power to keep NYC warm but I only use it to fly my helicopter... Zenoah gas engine is merely converted to water pump to cool this beast down...

-dave

[Orbital]

thanks man, that is pretty much what I'm putting together other than the fact that the system that i need to make 150W. but that is the same idea. I'm glad that someone else has proved that it works.
Do you have problems with running that system on start up? I dont think that there should be a problem but I have never made a set up like this on an RC airplane.