Building a plane using 30cc Homelite weed wacker- is this reasonable? Need your thoughts on this one.

I read up a little on using an Homelite weed eater engine for a model boat a few years ago. From my understanding the engines are designed so that they don't over-rev i.e. detuned. For converting the engine for boat use, there was a water cooling (head or jacket, I don't remember) and they had a back plate that boosted the engine power. I'm guessing for aircraft performance you'd want to find one of the backplates for higher power. The performance back plates went deeper into the engine to decrease the volume of the crankcase and increase pressure of the fuel/oil mixture going from the crankcase to the cylinder.
RogerN

On 24 May 2009 14:51:56 GMT, snipped-for-privacy@the.candy.store.com (Dany) wrote in :
Lots of people, I think.
I see to remember conversion kits for weed whacker engines being on the market. There was a big Cub a long time ago that set an unofficial endurance record with a chainsaw engine. They left the pull start on it and used it to get it going.
You won't get 3D capability from it.
Think "floater." Like a scaled-up ugly stick or a Cub.
As the OP said, you won't get a lot of power from it. But with the right prop, you will have an engine that will probably last about forever.
Marty

Here is a SPAD ( Simple Plastic Aircraft Design) built plane using your Homelite engine..

That's pretty cool but I want to shoot the camera man. mk

Converting weed whacker engines to model airplane engines was the popular thing to do for giant scale airplanes 10 or 20 years ago. Now there are quite a few purpose-built engines on the market that do much better, even when they use components from weed whacker engines.
I would suggest that about the only reasons to do this would be if you're tight for cash or if you'll find it fun. About the only way you'll do this and stay money ahead is if you have a well-equipped machine shop in your garage and a lot of drive; about the only way you'll do it fun ahead is if you want to spend your time tinkering with the engine, have a lot of drive, and _want_ a well equipped machine shop in your garage.
At the very least you'll have to machine up a prop hub; you'll very likely want to modify the flywheel for size and efficiency (without disabling the magneto), and you'll very likely have to mill out a mounting adapter from the engine to your firewall.
Then there's all the afore-mentioned performance issues.
Other than that it'll be easy and cheap.

Good points by responders. It seems like you'd do lots of work on the engine for a plane but many airframes would work and you'd do less to the engine for a buggy or car but lots of work on the car itself. Just guessing. :) mk

A few years back, there were quite a few plans/articles about using Ryoby weedwhacker engines. I'd suggest a few searches on Google or another search engine.
Maybe someone here has done it?
Geezer

Shooting the cameraman is too good for him.
I wanna know why he landed in the grass with all that runway around. :)

"Tim Wescott" wrote It isn't all that bad. I did it with only a friend turning a prop hub. The rest was done with a sawzall, dremell tool, drill press and assorted hand tools.
I "milled" the flywheel by cutting off the bulk, chucking the flywheel into the drill press, rotating it slowly to let the dremell tool grind of the fins to a reasonable level. Mount was done with a little bent aluminum and a few longer screws for the engine.
A bit of a floater is good advice, as it will not have more thrust than weight.

Well it looks like I'me heading for an airplane build. This is my first time build, I know the physics of flying and such but there will be more questions like:
How many channels/servo do I need?
What should I use to make the airplane frame that is light, easy to find and not too costly?
Are there any good plans out there that would show me a good place to start from?
What size prop would be required for my 30cc homelite and where is the best place to get them?
I have no idea where the servos are mounted for the flaps...that's scary.
I thank everyone for their responses. I've been looking long and large and a plane seems to be the better choice rather than a car. There are too many parts to build a tranny for a car instead of a propeller and plane body.
I am a retired army electronical mechanical engineer and do wood working as a hobby. I ready for a new challenge. If my plane doesn't fly, then I'll be the modern day Howard Hughes...minus the germaphobe!!!! LOL
Dany
"Geezer" wrote:

(t>>> As per the title, I have a 30cc homelite weed wacker engine. I know it >>> weighs Three or four, depending on whether you want ailerons. If you build something light then you can get away with "standard" sized servoes; if you build something zoomy you'll (a) need bigger servoes and (b) crash it 'cause you're a beginner.
Balsa and spruce. Sorry, but there's just no substitute for the kind of floater that you'll want to build. Check your local craft shop or (much better) your local hobby shop if you have one.
The Hobby Lobby Senior Telemaster is probably perfect for this, if you can lower yourself to building from a kit. If not that, then some other big (> 6 foot wingspan) light plane is the way to go.
You want something big and light, and the Telemaster is both.
Sig has a big Rascal model that would probably be suitable, too.
Try and look in their plans directory. Stay away from scale planes for your first effort -- you want something easy to build, fly and repair. Scale models -- even models of trainers -- don't fall into all three of those categories.
Big (probably between 12 and 14 inches, although someone will surely disagree and be right). You'll want to get them at your local hobby shop, or mail-order from someplace like Tower Hobbies.
If you mean "flaps" like "landing flaps" then you don't need them. If you mean "aileron, rudder and elevator" then it depends. If you get a kit or an ARF it'll all be spelled out.
If your primary goal is to learn to fly, consider going out and buying an almost ready to fly (ARF) trainer and learning on it before you start in with the Homelite engine. You _can_ do it the way you're planning, but its harder than getting and ARF, and in today's market it is probably more expensive to buy the parts than it is to buy a whole plane.
That Sig Rascal I mentioned _is_ an ARF, by the way, and would probably be a good platform for the engine.
You should also consider finding a flying field in your area (ask at your local hobby shop about where to find them, or look on the AMA web site -- . You'll learn a lot hanging out there and seeing how it's done; getting to see inside a trainer before you go off and build something will be a big help if you insist on doing it from scratch. Attach yourself to the folks that offer encouragement and ignore the folks that offer discouragement (much of the discouragement will be well meant -- as I said, you're choosing a tough row to hoe).
If you're lucky (and if you ask around) there may be someone at the field or a club nearby that has an airframe that's right for the engine. If you're _really_ lucky they'll be tired of it and you'll be able to pick it up cheap.

Sig Rascal was on my mind too but I think it's ARF, that takes some of the fun out of it. If Dany lives near me I'll start training him tomorrow. :) mk Central Texas

It's ARF. I was suggesting it in the theory that if you're spending lots of energy flogging an engine, you may just want to _buy_ the airframe, at least for your very first airplane.

"Tim Wescott" wrote
What he said!
Seriously, although some have taught themself to fly (I take from the tone of your questions that you do not fly RC, yet) the odds are way stacked against you teaching yourself on a home designed airplane. You need to be learning on a plane that has proven good manners, and flys without the extra skill necessary to set up a new, unproven design. Plus, the platform you learn on should be cheap and easy and cheap to repair. It will need to be, if you are like most learners. A model big enough to carry a 30cc engine is not going to be cheap or easy to repair.
If you have a good table saw, you can go down to the local big box lumber store, and usually pick through some two-by-fours or two-by-sixes and find some close grain, straight grained pine lumber that will make dandy parts for a model. Douglas fur also works great, but is a bit more costly. It is even stronger than Sitca spruce that is used in full sized planes, and not much heavier. Bass wood is great to work, but not as strong. It is stronger than balsa, but not as strong as most of the above mentioned pine, but it is also weaker. You will need to size the different woods correctly as it compares to balsa. You can use 1/4" fanfold styrofoam insulating material for skins, and it is somewhat structural, also. A big plane for a 30cc would take a lot of monocoat to cover it, and it is expensive. With the blue foam stuff, you can leave it blue, or paint it after you put something on to seal it. There are plenty web sites out there with the details.
You have a lot of learning to do, but it is fun learning. Hit the search engines on model airplane building, and such. There are videos out there, and plans are available at some sites.
Please, don't start with the big homebuilt plane, though. Use a teacher to take off, let you fly until you are about to crash, and recover from the bad situation you got into, then let you try again after he tells you what you did wrong. If you do use the big plane without a teacher, the chances are that you will not be successful, get frustrated and never stick with it long enough to stay in the hobby. A .40 size alcohol and nitromethane plane is your best bet, and going that route will leave you with a controller and servos to use when you build your big plane. Going electric is possible, but the chargers and such are a mite expensive if you are not going to be using them for future big gas planes.
As far as how to design your own, there is an excellent page somewhere on general "rules of thumb" for ratios of tail area to wing area, lengths and sizes of some part compared to another part, center of gravity, and so forth that will make about any design fly that is close in line with the generalities. Perhaps someone here has that page bookmarked and will tell you how to find it. There is nothing magic about building your own design. I've only bought one kit in the last 10 or so years. Designing and building is half the fun, to me.
Good luck, and let us know how things are going.

True story -- a guy shows up at the field with the big (10 foot ARF I think) Piper Cub. He had never flown RC -- but no fear -- he was a pilot and knew how to fly. About 5 guys offered to help and told him he was making a big mistake. But then, he knew how to fly. He was not in the air for a minute when he lost it. He dumped the remains in the trash, including the engine/electronics, even though he was told it could be rebuilt (it was later rebuilt by one of the guys there at the time). End of the hobby for him!
Good suggestions all. I suggest getting a copy of Real Flight (or a similar flight simulator).
Another true story -- I was at the field when a guy shows up with a small electric. He puts it on the runway and stands behind it for the takeoff. A dead giveaway forsomeone rerlatively new at the hobby. Flys it around a bit and gets it back to the runway in one piece -- very very pleased with himself. Turns out this was his first flight -- ever! His ONLY prior experience was with Real Flight.
Good Luck, Lee

Sorry MK, you're at the other end of the continent whereas I'm in the atlantic area. But thanks anyways for offering to teach me!!!
"MJKolodziej" wrote: Dnews:BNqdnaUWbpb7v77XnZ2dnUVZ snipped-for-privacy@web-ster.com...:> On Sun, 31 May 2009 21:51:20 +0000, Dany wrote:m> (top posting fixed)t>> "Geezer" wrote:n>>>"Dany" wrote in message >>>news:4a195f0c$0$32596$ snipped-for-privacy@unlimited.newshosting.com...h>>>> As per the title, I have a 30cc homelite weed wacker engine. I know ity>>>> weighsi>>>> a few pounds but >>>> if I remove all the unwanted fluff from it, I might be able to shed a/>>>> few pounds...or so I hope.>>>>> >>>> HAs anyone made such a beast fly? My guess is that I'd need a big wing >>>> span tos>>>> get it up. Right now, I'm debating to either make a 1/5 scale RC duneg>>>> buggy ors>>>> try to turn it into a plane.a>>>>a>>>> I am open to suggestions. Depending on the major concensus, it willr>>>> dictated>>>> what I'll do with my engine. Thanks for sharing your thoughts.M>>>> >>>> Danye>>>>a>>>>n>>>A few years back, there were quite a few plans/articles about usingi>>>Ryoby weedwhacker engines. I'd suggest a few searches on Google oru>>>another search engine. I'me heading for an airplane build. This is my first >> time build, I know the physics of flying and such but there will be moreo>> questions like:z>>m>> How many channels/servo do I need?(>)> Three or four, depending on whether you want ailerons. If you builda> something light then you can get away with "standard" sized servoes; ifd> you build something zoomy you'll (a) need bigger servoes and (b) crash ita> 'cause you're a beginner.e>k>> What should I use to make the airplane frame that is light, easy to findo>> and not too costly?o>d> Balsa and spruce. Sorry, but there's just no substitute for the kind ofb> floater that you'll want to build. Check your local craft shop or (muchy> better) your local hobby shop if you have one.e> >> Are there any good plans out there that would show me a good place toa>> start from?i> > The Hobby Lobby Senior Telemaster is probably perfect for this, if youw> can lower yourself to building from a kit. If not that, then some otherk> big (> 6 foot wingspan) light plane is the way to go.s>f> You want something big and light, and the Telemaster is both.a>d> Sig has a big Rascal model that would probably be suitable, too.n>o> Try and look in their plans directory.r> Stay away from scale planes for your first effort -- you want somethingl> easy to build, fly and repair. Scale models -- even models of trainers > -- don't fall into all three of those categories.y> best place to get them?d>f> Big (probably between 12 and 14 inches, although someone will surelys> disagree and be right). You'll want to get them at your local hobbyr> shop, or mail-order from someplace like Tower Hobbies.l>b>> I have no idea where the servos are mounted for the flaps...that'sk>> scary.a>d> If you mean "flaps" like "landing flaps" then you don't need them. Ife> you mean "aileron, rudder and elevator" then it depends. If you get ae> kit or an ARF it'll all be spelled out.r>y>> I thank everyone for their responses. I've been looking long and larged>> and a plane seems to be the better choice rather than a car. There are >> too many parts to build a tranny for a car instead of a propeller ands>> plane body.l>> >> I am a retired army electronical mechanical engineer and do wood workingr>> as a hobby. I ready for a new challenge. If my plane doesn't fly, thent>> I'll be the modern day Howard Hughes...minus the germaphobe!!!! LOL >o> If your primary goal is to learn to fly, consider going out and buying anb> almost ready to fly (ARF) trainer and learning on it before you start ind> with the Homelite engine. You _can_ do it the way you're planning, buti> its harder than getting and ARF, and in today's market it is probablya> more expensive to buy the parts than it is to buy a whole plane.w>m> That Sig Rascal I mentioned _is_ an ARF, by the way, and would probably > be a good platform for the engine.r>i> You should also consider finding a flying field in your area (ask at your > local hobby shop about where to find them, or look on the AMA web site -- e> . You'll learn a lot hanging out there ande> seeing how it's done; getting to see inside a trainer before you go off)> and build something will be a big help if you insist on doing it fromf> scratch. Attach yourself to the folks that offer encouragement andn> ignore the folks that offer discouragement (much of the discouragementt> will be well meant -- as I said, you're choosing a tough row to hoe).

Well Jim, I used to fly using a corded plan when I was about 7 years old. I also bought el-cheapo electric planes to fly around so I guess it doesn't really count as far as RC world goes. Like I posted to someone else, I want to prove myself I can build something that can fly. I bought the G-4 RC simulator and let me tell you, it is funny as hell to see how many planes I've crash landed!!!! I have a home theater with 144 inch screen so it is pretty realistic. My wife keeps telling me she wouldn't get on a plane or helicopter with me, at least not at the moment. She is also willing to help me build the plane.
There is no doubt in my mind that I might crash the plane. How many times have we crashed when we first started to walk? We learnt the hard way and I'm sure it'll be the same for RC plane.
The only thing I need to see now is an actuall plan for a plane. I've searched the web sites but none are telling me anything good. If someone out there has a few websites with any info that would be more than usefull, I'd be very happy to follow them.
Thanks again for your info and tips. It looks like this newsgroup has lots of experience in the wings.....(pun intended)
Dany
"Morgans" wrote:

I know, this flight simulator is a hoot! I think it actually contributed in my desire to build something that I could try to fly. I'm sure training with the sim will be better than just showing up in a field, turning the engine on, trying to lift off the ground only to see nose dive right into the side of my car... :o
Dany
"Lee B" wrote: Piper Cub. He had never flown RC -- but no fear -- he was a pilot and cknew how to fly. About 5 guys offered to help and told him he was making a 'big mistake. But then, he knew how to fly. He was not in the air for a tminute when he lost it. He dumped the remains in the trash, including the aengine/electronics, even though he was told it could be rebuilt (it was later rebuilt by one of the guys there at the time). End of the hobby for ihim!r Good suggestions all. I suggest getting a copy of Real Flight (or a similarhflight simulator).ntAnother true story -- I was at the field when a guy shows up with a small telectric. He puts it on the runway and stands behind it for the takeoff. A ldead giveaway forsomeone rerlatively new at the hobby. Flys it around a bit eand gets it back to the runway in one piece -- very very pleased with rhimself. Turns out this was his first flight -- ever! His ONLY prior lexperience was with Real Flight. fGood Luck,hLee

Dany, do you have any way of opening a .dfx file or other CAD file? I have ,somewhere, a file of a trainer that can be scaled up to whatever size you want. I printed it once on 8 1/5"X 11 paper that could be taped together.(I'll look for that file) I say build the plane and fly it! Please let someone experienced fly it first. Just trimming a new plane is a chore, let alone learning for the first time. mk