Power Up! Model aircraft engine to run generator?

[Steelwolf]

With all the talk of micro engines in this thread, and all the talk about super powerful lights that need ridiculous amounts of power in this thread, I was wondering if in some way, it might be possible to realise tomorrow's technology today, even if it wasn't really micro, but just portable?

And I thought, how powerful are those tiny, fuel-powered engines that they use on model aircraft? Does anyone know? Does anyone play with model aircraft here or have links to people who do?

I know that the engine runs at very high speeds but may not be capable of high torque, which may be what is needed to generate high amps. But perhaps it may be possible to design a system using stepdown gearing to increase the output torque. But of course the final question is: "Is there a electrical generator small enough to keep the total setup portable, but powerful enough to match the power of the engine?"

I figure a complete power pack setup consisting of engine, fuel tank, muffler (those things are annoyingly loud without them), gears, generator (which may be able to double as starter motor), starter battery and maybe a rectifier circuit or control electronics. It would probably be the size of a housebrick and a half, but shouldn't weigh so much. It should be suitable for those 300W and 600W lamps mentioned in the second link. And it would not be subject to recharge downtime. Just refuel and go.

I throw this out to you as a "Whaddaya think?" as I head out to look for more information about those engines. /ubbthreads/images/graemlins/grin.gif

 

[unclearty]

The small engines used for RC car racing are a little more "tourqey" than the airplane engines. I would imagine these would work better for your idea..and would be a little more quiet due to the lower rpms.

 

[Doug S]

There are some high rpm permanent magnet motors around that should be suitable for use as generators without gearing. With 100% efficient conversion, 1 hp = 746W. Allowing for conversion losses, you would need a bit over 1 hp to get that 600W outout. Honda makes a portable generator rated at 600W but it is considerably larger than your brick and a half. I believe that some of those larger model airplane engines are capable of a large fraction of 1 hp. I believe that there are some RC enthusiasts on the forum so you are likely to get some better answers.

 

[tonyb]

I had that idea years ago, when I go camping, I use white gasoline to run my miniture brass stove, I got to thinking why nobody makes a small 100w gasoline generator. The only problem with nitro engines is the high speed low torque from those types of engines the only alternitive is small propane gas turbine engine running a miniture generator and then transformers to step down the voltage. Or, maybe how a big carbon arc spotlight generator works they put out higher dc voltage and current . I found it its a called a Barlow generator you can make your own dc generator out of two magnets and a spinning copper disk to run a carbon arc light or welder or a smaller version would run leds, I'm going to test this theory tonight. It puts out dc current and voltage. Heres the web site: http://www.physics.umd.edu/lecdem/services/demos/demosk1/k1-41.htm

 

[JSWrightOC]

Hey guys...would one of these work? /ubbthreads/images/graemlins/smile.gif

They run on regular gasoline (4-cycle engine), the smallest puts out *clean* 1000W (sine-wave inverter) 120VAC and they run for hours on a tank of fuel.

 

[Rebus]

Most model airplane engines I
have had experience with, burn
too much fuel to be useful for
this kind of application.
About 1 cup of fuel for about
8 mins of running.

-Rebus

 

[Steelwolf]

TonyB: That's an interesting generator. I wonder if it will be able to generate quite enough power in a compact package. I believe it was why they went on to develop generators that used multiple coils of copper wire.

JSWrightOC: Not quite small enough, unfortunately. 29lbs still quite heavy for hand held. It might work for a backpack-type power pack.

Rebus: Thanks for that bit of information. I didn't realise it took so much fuel. Can you recall what size of engine it was?

I thought of model aircraft engines because I saw a guy playing with his model aircraft at a park recently. It was definitely a IC engine. I think it was the "glow" type. It had to have gone for at least 10min if not closer to 15min (I could hear it going all the while I was jogging that section of the park, and it came into view after around 10-15min of jogging). And it wasn't a really big plane, so I don't know where it could have stored more than a cup of fuel. And those aircraft engines seem to keep going despite doing all those aerobatic manoeuvres, which is a necessary aspect if we don't want the light to sputter every time we move it.

From what I've found so far on the net, it would seem that there are small 2-stroke and 4-stroke IC engines, running on either glow plugs (which means high rpms and specialised glow fuel) or slightly larger engines using spark plugs and regular gas (but bigger, bulkier, more complicated).

I have got to find time to go to the local hobby store and talk to the experts there. I'll bet they've never had a set of questions like mine. /ubbthreads/images/graemlins/tongue.gif

 

[Steelwolf]

Just had a look at one of the other threads that sparked this one off. Looks like the 600W aircraft landing light is running. 25 D-sized NiCd cells for 8-9min of light.

Is it possible to go one better with a IC engine-generator setup? Definitely the recharge time would be much shorter. /ubbthreads/images/graemlins/smile.gif But can it be done within the same size/weight restrictions as 25 D-sized cells?

BTW, why am I even thinking about this? Am I nuts? The SF KL1 is as bright as I usually need a light. Why am I thinking about ways to generate enough power for 600 of them? /ubbthreads/images/graemlins/crazy.gif /ubbthreads/images/graemlins/icon15.gif /ubbthreads/images/graemlins/huh.gif

 

[shankus]

Because it's there?
I like the idea, just because it's unusual. Maybe a small generator capable of being driven from one of the motors doesn't exist, but I have no doubt that one could be made.
Surely not 600 watts, but what about say, 25 watts, or under? Thats still quite a bit of light.

I have no experience with these motors, but I'll be watching this thread as the experts weigh in.

Thanks for posting it...

 

[Cougar_Allen]

Maybe reading that thread about the 600w flashlight has addled my poor weak brain, but I started thinking about generators too, early in (my reading of) that thread, and then I got to thinking burning gasoline to generate electricity to turn the electricity into light might not be the most efficient possible way to get light out of gasoline ... and gasoline might not be the best fuel.

Suppose for some unimaginable reason someone wants to outdo that 600w handheld light ... just in the spirit of anything worth doing is worth overdoing, maybe ... how about scaling up a carbide lamp? I hesitate to even use the word practicality in this context, but if we're looking for the most powerful light that can be handheld ...

It's going to get hot, of course. Heat is probably going to be the limitation; I think that'll be more of a problem than weight. If we're satisfied to run it for only a few minutes at a time, though ...

-Cougar :{)

 

[Doug S]

[ QUOTE ]
Steelwolf said:
BTW, why am I even thinking about this? Am I nuts? /ubbthreads/images/graemlins/crazy.gif /ubbthreads/images/graemlins/icon15.gif /ubbthreads/images/graemlins/huh.gif

[/ QUOTE ]

The answer to your second question is yes. For your first question, see second question. /ubbthreads/images/graemlins/grin.gif

 

[Tomas]

Re: Power Up! Model aircraft engine to run generat

*sigh* I can just see it now: A Stihl Spotlight.

Picture a chain saw engine/housing mated to a landing light by way of a hight efficiency generator ... /ubbthreads/images/graemlins/grin.gif

Portable, noisy, smelly, heavy, but damned bright!

 

[Steelwolf]

Re: Power Up! Model aircraft engine to run generat

Shankus: Not 25W. That is too little power to bother with the difficulties of a gas engine-generator setup. You can adequately supply that level of power with a bunch of batteries. It would be lighter, more robust and definitely easier to maintain. But probably starting at about 100W, up to 500W. There are still no generators for this size of power output. Any bigger and you can go into the currently available commercial models.

Of course, when you start thinking about this, it is for fun, for the "because it's there" mentality. But soon you wonder if there is actually a practical use for it, or if it can be done at all. Would anyone out there actually need a 100W generator, or even a 300W generator? RVs need more power than that, backpackers don't seem to need anything like that. I'll have to think more about that one. But in anycase, it is to be done, it has to be hand carry size and weight. Any bigger and there would be no point at all. Which is probably why you can't find commercial models at this size.

Cougar: When you think about it, the old lighthouses were run using a kerosene pressure lamp. And those things, even without the focusing lenses, were bright. I can imagine a handheld setup using a similar pressure-fed system, but running maybe a ceramic or carbon mantle. Something robust enough not to break every time you moved the lamp. May not be as bright as a lighthouse lamp, but then again, very few lights actually are. Heat would not be a serious problem as you can see it being handled well with gas lanterns like the Coleman NorthStar.

 

[Stainless]

Re: Power Up! Model aircraft engine to run generat

SteelWolf:

Have you checked into fuel cells? The state of the art seems to be advancing rapidly, with miniture modles being developed for laptops and cell phones. Fuel cells tend to be "stackable", just like batteries. You'll have to do your own homework to see what is actually available at this point in time, but fuel cells should bypass your concerns about noise and vibration.

 

[JSWrightOC]

Re: Power Up! Model aircraft engine to run generat

Click here.

Anything look appealing? /ubbthreads/images/graemlins/tongue.gif

 

[Steelwolf]

Re: Power Up! Model aircraft engine to run generat

Stainless: Yeah, happened to glance at Popular Mechanics and saw that they flew, for the first time, a small aircraft (kit model size, IIRC) running on fuel cells utilising hydrogen. It was a dumb plane (no form of remote or on-board control), but it was small. Who knows, fuel cells might soon be it. But for now, most of the smaller units need hydrogen, which makes it difficult to refuel and not very practical for the average user. And besides, they are very expensive. Check out the link the JSWrightOC has provided. Over $3000? I think the macro-engine might be built for 1/10th the price.

The one which caught my eye was the PM122 alkaline cell. Magnesium anodes, saltwater as electrolyte. Operating weight would be about 5kg (dry weight 2.4kg + saltwater ~2kg). 35-50hrs on one set of electrodes, with total operational life of approx. 1,400hrs. Power output 100W @ 12V 8.33A That is very very impressive. But is there some way to increase the power output at the expense of run time? Is there a unit designed to do that?

But who would use it, or the macro-engine/generator? Search and rescue teams? Disaster response units?

 

[JSWrightOC]

Re: Power Up! Model aircraft engine to run generat

I would imagine that disaster response and S&R would use whatever the most reliable form of energy storage/production is. That means batteries and generators. I could see someone strapping one of those 29lb Honda generators to theier back and carrying a 1000W (halogen? bright...metal halide? VERY bright! /ubbthreads/images/graemlins/grin.gif) light pole with them before they use a Nitromethane engine-powered generator. I have some experience with nitro engines, and they can be quite finicky. Unless tuned properly, they might stall or fail without warning. Also they don't last much longer than 5-6 gallons of fuel.

If someone *did* want to build such a beast (just to be unique) I would go for something like this from OS Engines. 3.9bhp @ 9000 RPM is very useable, and the micro-controlled mixture eliminates all tuning issues. Just make sure you keep it cool!

 

[Stainless]

Re: Power Up! Model aircraft engine to run generat

Steelwolf:
The ones (suppossedly) being developed for cell phones and such get thier hydrogen by extracting it from rubbing alcohol.

JSWrightOC:
Regarding your sig: "I can see it now. One of these days we're going to mine our own landfills for the natural resources we have thrown away."
We are already doing that - inserting perforated pipes into landfills to collect methane (natural) gas! Sorry I don't have a link, but I do believe that this IS HAPPENING, and on a commercial scale. Eventually we may begin a strip mining process to recover some of the zinc from all those batteries we've been throwing away. /ubbthreads/images/graemlins/grin.gif

From the link posted above: http://www.fuelcellstore.com/cgi-bin/fuelweb/view=item/cat=28/subcat=73/product=369


Item Number 541057
Unit Price $9.95


PRODUCT OVERVIEW

Replacement cartridge for 4 in 1. If purchased separately this units requires the SmartCord that is designed for your device. Choose from the list below.
Zinc Air Fuel Cell Power Cartridge
Capacity: 3300 mAh
Dimensions: 52 x 68 x 13 mm (2" x 2.7" x 0.5")
Weight: 76g (2.7 oz.)
Operating Voltage: 4.8 - 3.6V

Price = $9.95 .... its probally not (yet) refillable, but a step in the right direction.

 

[Doug Owen]

Re: Power Up! Model aircraft engine to run generat

Fun topic.

Folks seem to be getting to the 'need a HP or two, how about chainsaw (and similar) engines', which seems logical to me.

If the goal is bright light, I kinda like the 'carbide' idea, perhaps with a twist. How about 'Lime light', the stopgap between the high tech keroscene lamps used for stage lighting and arc lights, the source of 'in the limelight'. Very bright, and doesn't use any electricity at all.....

Doug Owen

 

[JSWrightOC]

Re: Power Up! Model aircraft engine to run generat

Stainless:

Yeah, I thought that up one day (along with the other one) and decided I would put it in my sig line. You're right, we are recovering methane from our landfills, which is a by-product of the decomposition of the organics. I beleve we recover methane from cow pies and sewage processing facilities as well. Mining the zinc sounds like a good idea to me! Maybe we should also go after all the gold plating, polymers, steel, aluminum, nickel, etc. that we've pitched too.