Okay, I could use some advice here. I just bought a Ryobi 26cc four-stroke off eBay and I honestly don't know a thing about this particular engine. I would like to use it in something like a Balsa USA Fokker DR-1 or, maybe, a D VII. But first, a few questions.

Is it safe to run this engine inverted knowing that the oil is kept in a sump? What prop sizes are suitable for this engine? Being a four-stroke, it should make its power at the lower end of the rpm band. Would it be worthwhile to toss the magneto and convert it to electronic ignition? From those who have been using this engine, any suggestions, comments or things I should be aware of?

Thank you all in advance and I look forward to hearing your input.

Al