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propane weedeater engines in planes?

Old 05-20-2009, 10:29 AM
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brett65
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Default propane weedeater engines in planes?

I have a couple weedwacker engines, 25 & 30cc that run well, but I hate the weedeater so I may put one in a plane eventually, but I looked at the new propane powered weedeaters today. Could these new weedeater engines be used to power a plane? They seemjust as powerful, will run for two hours on a $3 bottle of propane and start much easier and there is no oily exhaust. Since there is no oil/fuel mix, I guess that have a wet crankcase with oil so they may be heavier, any thoughts?

What's a good plane to put a weedeater engine in? Not just a big trainer though.
Old 05-20-2009, 10:34 AM
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Minnreefer
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Default RE: propane weedeater engines in planes?

I would think the biggest question is weight, I know a lot of people convert old weed eater engines to planes, but I think they take a LOT of weight off the engine,   It does sound intersting.
Old 05-20-2009, 10:34 AM
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MinnFlyer
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Default RE: propane weedeater engines in planes?

Hmmm... sounds mighty tempting!

Basically, any 120-size plane is a good candidate for a 23cc gasser.
Old 05-20-2009, 10:36 AM
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Default RE: propane weedeater engines in planes?

If it is big enough to carry the size and weight of the engine and fuel system it is a good candidate. Anything other than a huge trainer sort of takes it far beyond the beginner forum though.
Old 05-20-2009, 10:36 AM
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alfredbmor
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Default RE: propane weedeater engines in planes?

Usually propane comes in a high pressure container which could be an issue for a model airplane aplication.
All engines require lubrication, not knowing my self about those engines I would think that those engines should be heavier because of an included lubrication system.
Anyway this is a hobby and we all experiment with many things that are handy, just take care of those containers under pressure.

Good luck.
Old 05-20-2009, 10:49 AM
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Default RE: propane weedeater engines in planes?



http://www.pronto.com/Lehr-Propane-C..._1197444456-PP# here's one example of a propane weed whacker. uses a 16 OZ tank of LPG but I don't know if that is weight or volume or both??





Interesting concept worth further research.

Old 05-20-2009, 11:00 AM
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Default RE: propane weedeater engines in planes?

can't resist, but just think, when you crash-instant outdoor grill
Old 05-20-2009, 11:11 AM
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Default RE: propane weedeater engines in planes?

Look at it this way:

You buy the weed wacker for $200. Then you need to take it apart. Then you throw away all of the non-engine parts. Now you need to make a prop adapter.

Unless you are a machinist with access to a lathe and milling machine, you'll have to have one made for you. I used to be a machinist and I can tell you that it won't come cheap.

Finally, you'll need to adapt the mounts to fit a firewall (Back to the machine shop).

Or... you can spend another $100 and get one of these, bolt it in and you're ready to go.

http://www3.towerhobbies.com/cgi-bin...&I=LXNRH4&P=SM
Old 05-20-2009, 11:17 AM
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Default RE: propane weedeater engines in planes?

probably the biggest things to overcome besides the weight of the tank, would also be the added weight of the regulator and you'll need some sort of shut off valve so you wouldn't have to take the plane apart after each flight to shut the tank off
overall this is a good concept, my childish imangination is seeing a plane flying a night with flames coming out the tail, cool
Old 05-20-2009, 07:07 PM
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ChuckW
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Default RE: propane weedeater engines in planes?

Anything is possible if you want to bad enough. The propane cylinders those things use are pretty heavy though. Maybe some sort of smaller, aluminum cyclinder would work better.

Like Minnflyer pointed out there is a lot of work involved with making it work. I have a 30cc 4-stroke powerhead for a string trimmer that I was going to convert for fun but decided against it.

I also doubt that the performance would be as good as a comperable displacement purpose-built RC gasoline engine.

If you want a cheap gas engine, look at some of the Chinese stuff out there right now, not bad considering the price.

Of course it isn't always about practicality. Sometimes tinkering and having fun is nice.
Old 05-20-2009, 09:18 PM
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Default RE: propane weedeater engines in planes?

Iwas trying to find a manual for it, but come up empty handed. I did find a feedback about the manual saying to use the full 2.7 p oz of oil shipped with it and in fact the crank case only hold 2 oz, so oil was coming out all over.

This means it's a wet crank case, which also means it may not like long inverted flight or some of the other crazy stuff we do. I don't think the regulator on the tank is an issue, there has to be a shutoff for the trimmer, I'm guessing the carb is the regulator. There isn't much pressure in a propane cylinder.

I've got to tell on myself here, When I moved from NY out here to CA, the moving company made me empty the tank on my gas grill. Thinking it was just a mater of leaving the regulator off and opening the valve, I did just that. After about two hours, I had only lost about 5% of the tank. "oh yes, I say to self, it "Liquid"', so I just pick up the tank and set it down upside down. Whoshh, out comes the propane. Then I looked down in the little valley behind my house and I discovered the Propane/LPG is heaver than air and there was this huge fog bank of propane, about an acre of of just setting there. I was sure that there was not going to be a need for the moving van that was to show up the next morning. All I could see was this huge blast when all the propane mixed with all that air ignited. Luckly nothing happened, and none of the neighbors called the fire department. I think I may have found a way to wipe out the local insect population though.

Don
Old 05-20-2009, 10:10 PM
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Default RE: propane weedeater engines in planes?


ORIGINAL: ChuckW

Anything is possible if you want to bad enough. The propane cylinders those things use are pretty heavy though. Maybe some sort of smaller, aluminum cyclinder would work better.

Like Minnflyer pointed out there is a lot of work involved with making it work. I have a 30cc 4-stroke powerhead for a string trimmer that I was going to convert for fun but decided against it.

I also doubt that the performance would be as good as a comperable displacement purpose-built RC gasoline engine.

If you want a cheap gas engine, look at some of the Chinese stuff out there right now, not bad considering the price.

Of course it isn't always about practicality. Sometimes tinkering and having fun is nice.

From what I found they use a splash system of lubricating. My old '53 chevy pu was like that.

Inverted flight prolly wouldn't be a big problem nor would most aerobatics. Radial engines have about 2 or 3 upside down cylinders and they do just fine. You would have to be careful about startup if mounted inverted though. A radial has to be turned over by hand several times to pump out the oil that settled in the bottom cylinders or it would hydro lock and break a piston or rod.
Old 05-20-2009, 10:44 PM
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Default RE: propane weedeater engines in planes?



can you do it? sure



is it worth the effort, in my opinion no but thats your choice not mine. look at the pirce of the engine on the link and i think you will understand my point of view. http://www.troybuiltmodels.com/items/RCSSV26.html ($175)



now if you just want a propane powered plane for the hell of it, go right ahead







Old 05-20-2009, 10:48 PM
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Default RE: propane weedeater engines in planes?


ORIGINAL: jimmyjames213



can you do it? sure



is it worth the effort, in my opinion no but thats your choice not mine. look at the pirce of the engine on the link and i think you will understand my point of view. http://www.troybuiltmodels.com/items/RCSSV26.html($175)



now if you just want a propane powered plane for the hell of it, go right ahead








LOL, this was in the overview of that engine "Propellers: Larger props will give more vertical performance with light planes, and less vertical performance in heavier planes." Well duh!
Old 05-21-2009, 08:30 AM
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Default RE: propane weedeater engines in planes?

Being that the engine is a 26cc 4s, I would be curious about how much power it has. It may not be very power efficient. I'm also curious about how much the fuel canister weighs. To be safe, I imagine the walls have to be sufficiently thick, but with most gassers, you are already hauling about 16 oz of fuel up with you.
Try it and let us know how it works. Try not to set anything on fire.
Curtis
Old 05-21-2009, 10:19 AM
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Default RE: propane weedeater engines in planes?


ORIGINAL: beau0090_99

Being that the engine is a 26cc 4s, I would be curious about how much power it has. It may not be very power efficient. I'm also curious about how much the fuel canister weighs. To be safe, I imagine the walls have to be sufficiently thick, but with most gassers, you are already hauling about 16 oz of fuel up with you.
Try it and let us know how it works. Try not to set anything on fire.
Curtis

Whoa, I'm not gonna try it. I was just wondering about peoples thoughts about the concept. I'm lucky right now to afford the proven things, so I'm not gonna experiment. I'll let someone else do that.
Old 05-21-2009, 11:32 AM
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Default RE: propane weedeater engines in planes?

My experence with anything internal combustion engine ran on LP is they run hot, very hot. The only thing I could imagine sticking it on would be an open engine plane. The LP cylinders are not as light as our plastic tanks but the weight of the liquid is quite a bit. As far as the regulator, not needed, most run straight tank pressure, the regulator doesn't have enough flow to keep up with the rpm's of the engine. Last thing you'll have to think about is it's a 4 cycle, with oil in a crankcase, even fuji who makes a 4 cycle gasser states that the engine has to be mounted with cylinder upright, so you can't put it any other way except upright. You can still do aerobatics, but sustained vertical climbing and inverted flight would kill the engine. Conversion cost are mild if done right, but cobbled together adapters are unsafe in any way or being. I thought many times of taking the 32cc leaf blower enging and converting it, but declined because there are way too many cheap great running gassers on the market to bother investing my time into making a flying turd.
Old 05-22-2009, 09:11 PM
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Default RE: propane weedeater engines in planes?

it is a 4 cycle wet sump type engine and the propane tank weighs about 2 pounds full. the shutoff on them is similar to a choke so the same servo setup would work.
Old 05-22-2009, 09:58 PM
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Default RE: propane weedeater engines in planes?

Im pretty sure you could use an air tank(s) used for retracts as a fuel tank.

Steven
Old 05-22-2009, 10:24 PM
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Campgems
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Default RE: propane weedeater engines in planes?



I'm not sure the lines and valves would stand up to it. Remember it is more like gas than Air.

Don

Old 05-22-2009, 10:30 PM
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Default RE: propane weedeater engines in planes?


ORIGINAL: Campgems



I'm not sure the lines and valves would stand up to it. Remember it is more like gas than Air.

Don

Aren't most air valves brass or alunimun? That is what regulators and valves on propane tanks are made of. I don't think that propane would have any adverse effect on plastic tubing either, I'm pretty sure its not corrosive. I think his main point though was that the retract can has the same top as the small propane cans, I don't know if thats true or not but I think that is what he meant.
Old 05-22-2009, 10:39 PM
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Default RE: propane weedeater engines in planes?



small paintball c02 canister? i think you may have a problem transfering the propane though

Old 05-22-2009, 10:42 PM
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Default RE: propane weedeater engines in planes?

I'm not sure talk to a local jet guy... alot of the pre kero start turbines used to carry propane in a small tank on board for the start sequence
Old 05-22-2009, 11:22 PM
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Default RE: propane weedeater engines in planes?

There you go.This is the great part about RCUniverse. The answers some from unexpected places.

Don
Old 05-23-2009, 10:23 PM
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Default RE: propane weedeater engines in planes?


ORIGINAL: MinnFlyer

Look at it this way:

You buy the weed wacker for $200. Then you need to take it apart. Then you throw away all of the non-engine parts. Now you need to make a prop adapter.

Unless you are a machinist with access to a lathe and milling machine, you'll have to have one made for you. I used to be a machinist and I can tell you that it won't come cheap.

Finally, you'll need to adapt the mounts to fit a firewall (Back to the machine shop).

Or... you can spend another $100 and get one of these, bolt it in and you're ready to go.

http://www3.towerhobbies.com/cgi-bin...&I=LXNRH4&P=SM
You can also spend 3 months building up a plane from a kit that you could buy as an ARF and have flying in one weekend. By the time you buy the covering and all the other goodies, the ARF is no more expensive than the kit. Yet I still buy the kit because I still like to dink with it, do it my own way, etc. Sometimes you gotta do it for the sake of having fun. And don't forget the marshmellows and a stick.


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