ORIGINAL: fireman7875
I am preparing to build a Sig 1/4 scale Spacewalker II. I want to use a gas engine and am trying to decide which one. I am considering a Brilelli 26cc but I also have a Homelite 25cc weed eater and a Ryobi 31 cc that I could convert at minimal cost. What sounds like my best option in terms of what will fit best in the plane? Does anyone have any dimensions on the converted ryobi or homelite. I am concerned that it will be too long to fit in the cowl. I also know where I could get a Quadra 35 at a good price. How would that fit? Any help appreciated!
Brian
I have both a converted Homelite and Ryobi engine. The Ryobi has not flown but the Homelite did until I snapped the magneto coil off (now swapping crankcases).
Both engines are near identical in size when converted (subject to variations in conversion kits and whether electronic is fitted).
The Ryobi is a smaller case and narrower is width, given the muffler and carb are on the rear. For the Homelite it will be wider due to side carb and exhaust.
Take into account that while Homelite and Ryobi flywheels differ slightly, they are essentially the same dimension wise.
Length wise, that will depend on the conversion method used but it would be easier to make a shorter Homelite conversion simply because there is no requirement to leave carb (and breathing) space at the rear. Other than the carb issue, both engines are probably similar in overall length.
If you want, I can measure my Ryobi tomorrow morning and then give a rough measurement for a Homelite (noting my Homelite engines are currently disassembled).
One thing I will say is that I think the Homelite is a better built engine (excluding the coil mounting) than the Ryobi. It at least has a proper alloy connecting rod and crank counterweight whereas the Ryobi makes do with stamped steel pieces laminated/rivetted together (Note: based on the engines I've had apart....perhaps Ryobi has changed this).