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  1. #1

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    First conversion pick a engine 5-choices?

    Ok I going to try my first conversion. I have five motors to pick from they are.
    Mac 140 chainsaw, Mac 160 2.0 cid chainsaw, a mac eager beaver II-sx weedeater, (can't find any size info on any of these)?

    Homelite chainsaw v1 super 2 (size?)

    and a Roybi weedeater 745 or 790 model I can't remember..assume a 31 cc size

    Which one of these would be the best to convert and give the most power.. From what I've read on here I think the homelite or the Roybi.

    I want to try the GAS/GLOW method to help reduce weight..

    The motor will go in to a 80" AT-6 Texan

    thanks in advance for any info and comments..


    I can take pics of each if it helps.


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  2. #2
    av8tor1977's Avatar
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    RE: First conversion pick a engine 5-choices?

    Without doing research looking the numbers up, I believe everything you have is in the 28 to 32cc bracket. The Homelite will probably be the most powerful of the bunch. If my memory of the model numbers is correct, everything you have is relatively easy to convert. I have several conversions flying from 23 to 42cc, and I'm using Gas/Glow in all of them.


    Good luck and have fun,
    AV8TOR
    If it is not SCARY, it is NO WHERE NEAR powerful enough!!
    All R/C planes have expiration dates---> It's just not printed on them anywhere!

  3. #3

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    RE: First conversion pick a engine 5-choices?

    I agree the Mac 2.0 converts to 33 cc I assume the mac 140 is around 28cc but the eagar beaver II is real small. All of these but the Roybi are pretty old most have big carbs with dual needles. I was just looking at the homelite and it looks like the easist to mount also.
    There are two fittings coming from the crankcase, I think then went to the oiler do I just plug these off.

    Thanks for the response Av8tor, I've read all you post on the gas/glow stuff and I think that is the way I'm going to go..
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  4. #4

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    RE: First conversion pick a engine 5-choices?

    Hi,
    The Ryobi would be the easyest to convert. It would require the least cutting and conversion parts are readily available. Borrow a carb from a saw. This will give you a big bore of 11 to 12.7mm. Since you are going to do them all, do the easy one first.

    Dave
    Every day above ground is a good day.

  5. #5
    av8tor1977's Avatar
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    RE: First conversion pick a engine 5-choices?

    I have to disagree with you on this one Dave. With the Ryobi, he will either have to buy a mounting kit, or make one with the carb spacer, special backplate, spacer bolts, etc. The Homelite from the chainsaw should involve no cutting/grinding, and can be beam mounted like a model airplane engine with just a couple of plates like for a Poulan chain saw engine. The Homelite will assuredly have more power than the Ryobi as well.

    Just my two cents worth....

    AV8TOR
    If it is not SCARY, it is NO WHERE NEAR powerful enough!!
    All R/C planes have expiration dates---> It's just not printed on them anywhere!

  6. #6

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    RE: First conversion pick a engine 5-choices?

    Av8tor,
    The V1 Super 2, I beleive is a reed valve, needle bearing crank saw. It has 31.9cc. I have a 26cc XL that I beleive is a slightly smaller version. I had to trim away chain oil pump casting. It has rear exhust and carb on the bottom of the case. I will use a plate for a radial mount. It isn't like the current powerstroke engines that adapt so well to our needs. Here is a link for the saw spes's an a picture of a 30cc needle bearing engine.

    http://www.acresinternet.com/cscc.ns...f?OpenDocument
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    Every day above ground is a good day.

  7. #7

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    RE: First conversion pick a engine 5-choices?

    Hey Dave mine does look like your rear exhaust bottom carb, but it has the side beam type mounts. It also has a real short Keyed shaft, that will have to have some kind of spacer to mount prop with. I assume I just plug the crankcase vent that runs the oiler or does it need to be vented somewhere?..

    Also after I took a good look at the carb it only has a low needle so I guess I'll need another carb..Right?

    I could steal a carb off the MAC but they are MOC brand and look really old.


    I'll take a pic tonight and post it when I get home

    Thanks for your help guys..
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  8. #8

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    RE: First conversion pick a engine 5-choices?

    Dale,
    I guess AV8TOR was right about the beam mounts. That is great. I can't seem to visualize the keyed shaft. Usually you have a taper for the flywheel followed by threads. All extra holes in the case, except the pulse port for the carb must be plugged. You can tap and fit with a screw or fill with JB Weld. A carb with two needles is best. You can test it with a single needle carb. Some older carbs have a second needle recessed and covered over with sealant. If the Ryobi has good compression, it could be converted quickly for a few bucks with parts from Wackerengines.com

    Dave
    Every day above ground is a good day.

  9. #9

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    RE: First conversion pick a engine 5-choices?

    Here are the pics.
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  10. #10

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    RE: First conversion pick a engine 5-choices?

    What do ya'll do for a spacer between the motor and the prop hub.. It will be sorta tough for me to cut down the fly wheel, being I don't have access to a lathe.
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  11. #11
    av8tor1977's Avatar
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    RE: First conversion pick a engine 5-choices?

    Since I always convert to electronic ignition, I have often taken a hole saw and cut the middle of the magneto out and used it behind either a commercial prop hub, or one that I make myself. A commercial prop hub is only around $20.00.

    AV8TOR
    If it is not SCARY, it is NO WHERE NEAR powerful enough!!
    All R/C planes have expiration dates---> It's just not printed on them anywhere!

  12. #12
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    RE: First conversion pick a engine 5-choices?

    ORIGINAL: av8tor1977

    Since I always convert to electronic ignition, I have often taken a hole saw and cut the middle of the magneto out and used it behind either a commercial prop hub, or one that I make myself. A commercial prop hub is only around $20.00.

    AV8TOR
    one of these days you will have to post a how-to for installing an electronic ignition with some pictures. i have wanted to try doing that but am intimidated by the process.
    UltraSport Brotherhood #54, Sig Brotherhood #46

  13. #13

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    RE: First conversion pick a engine 5-choices?

    Ok so I finally got time to work on this thing, and got all my parts together.. I chose the homelite 32cc . I got it mounted and after some effort got it running on the glow /gas mix, one time I had 7500 rpm on and 18x8 master airscrew. Is that pretty decent.

    I just got started messing with the needles and getting the transition set when my motor mounts bolts backed out,, so I shut it down to tighten them and guess what I striped not one of them but both bolts on the left side... DUHHHHH.. So now I'll have to figure out a way to remount the engine..

    I see Dave used a back plate and cut off the side mounts, I check and see if I can do the same..

    I'm not sure of my fuel mix, the only car fuel I cound find @ the store was the Traxxes brand and it doesn't show the oil % but the owner said he thought it was 12%. So if that is right I'm running about 25 to 1 mix. a little rich but it ran pretty good..

    ANy comments on the set-up will be greatly appreciated..

    Thanks guys.
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  14. #14

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    RE: First conversion pick a engine 5-choices?

    If you have enough metal just drill and tap stripped holes to next size bigger. Maybe? Capt,n
    Imagination is far more important than knowledge. Albert Einstein.

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  15. #15

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    RE: First conversion pick a engine 5-choices?

    Dale,
    Below the exhust you will find som aluminum boses. These can be drilled and taped for a radial mount. Just attach a plate mount with flat screws and spacers if needed. The side mounts can be cur off. This will save weight all the way around. Use locktite. My Homelite 26cc, lacks a needle bearing at the top of the conrod, like the early Quadras. This means that you need to use more oil. Maybe 32:1 or 4% minum if this is your situation also.

    Dave
    Every day above ground is a good day.

  16. #16

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    RE: First conversion pick a engine 5-choices?

    Thanks Dave I think I'm gonna try your mount.

    I used traxxas fuel and the hobby store said its 12% oil so that would put me @ 25 to 1 ratio.

    and Dave, I think me and you have the same engine supplier, looking at another topic I see you have a Mac 21 you were working on, I have the same engine on the bench next to covert...

    http://www.rcuniverse.com/forum/m_4532482/tm.htm
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  17. #17

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    RE: First conversion pick a engine 5-choices?

    I have a Sthil 76 weed eater i was thinking of converting but had wondered what size plane it would fly. Any help would be great thanks


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