Shaun K Posted January 15, 2009 Share Posted January 15, 2009 Hi all, I'm interested in hearing feedback from those that have had a go at converting an engine from a line trimmer / whippersnipper / brushcutter / weedwhacker (it seems they're called different names in every country) and stuck it in a plane. There appears to be quite a following for these conversions in the USA but I've not seen any real conversation on this fine forum on the topic. I've managed to get hold of a very low use 31cc Ryobi engine for $30AUD (aussie dollars) which is not much more than 10 pounds I believe. I'm keen to throw it into some kind of quick to build mule for a bit of fun. I don't expect the performance to match a commercial aircraft specific petrol engine, but feedback on USA forums suggests that they perform somewhat equivalent to a good 1.08 or a cheap 1.20 glow. Have you done a conversion like this or do you know anyone who has? What were the results and lessons learned? Quote Link to comment Share on other sites More sharing options...
Hugh Coleman Posted January 16, 2009 Share Posted January 16, 2009 An intersting question. I reckon I can tell you exactly which Riobi line trimmer it came off too. My Riobi lost its rotor on the fourth use! I think you will have problems with the Crank shaft - Prop mounting. From memory, the Crank on these line trimmer engines is very short and once the centrifugal clutch is removed, there is not a lot to work with. I have been thinking that my own engine will only be useable if I actually remove and replace the Crank. I would not trust a grafted shaft to perform on an engine of this size. Cheers, Hugh Quote Link to comment Share on other sites More sharing options...
Shaun K Posted January 17, 2009 Author Share Posted January 17, 2009 Thanks Hugh, At least in the older Ryobi gear there are two main types - "Long shaft" and "Short Shaft", where mostly short shaft engines come from applications where no clutch is needed like a blower or the cheaper line trimmers with no clutch, but typically anything which has a centrifugal clutch had a longer shaft. I have the longer shaft version, with roughly 60.5mm from the crank case to the start of the external thread and a total of 90mm from crank case to the tip of the crank shaft. There's plenty of length there to work with and turn up a prop hub on a lathe. I've recently bought a new Ryobi line trimmer (to be used for it's intended purpose) and the engine is totally different to the older ones and I havne't taken it apart to see the details yet. It also seems heaps more powerful than the old one. I'm just keen to get feedback from this forum because those offering advice and comment on this forum appear to be more knowledgable than on some other forums I've read... Quote Link to comment Share on other sites More sharing options...
Hugh Coleman Posted January 17, 2009 Share Posted January 17, 2009 Hey Shaun, I can only agree 150% on your last paragraph there!. This forum and RCM&E in particular have been instrumental in rekindling my interest in RC flying. RCM&E is obviously a publication for the experienced Flyer, but it does not read as such. It is so informative and encouraging to the Novice that it covers all bases brilliantly. Sorry I cannot help you more on your project. Cheers, Hugh Quote Link to comment Share on other sites More sharing options...
Nobby Clarke 2 Posted January 18, 2009 Share Posted January 18, 2009 HiShaun, Here is a couple of links that might help, iIstarted to convert a homelite 6 months ago and got side tracked there are others, i'll post later when I find them. wacker engines ch ignitions Paul Quote Link to comment Share on other sites More sharing options...
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