Alternate fuel options to 100LL

Not necessarily. Quite a few people, including myself, are burning MOGAS with their Lycos. Guess the main issue is a well designed fuel system to prevent vapor lock

See more here

Point to consider:

• Check Lycoming support for European auto-fuel in IO390EXP-119
• Check Vans support for European auto-fuel in RV14
• Design fuel system that prevents vapor lock
• Design emergency procedure to handle vapor lock

From Lycoming:

Original document:

About Unleaded Fuels, by Lycoming

• Airworthiness By Design: https://www.lycoming.com/content/unleaded-fuels-part-1
• Pump Gas is Not Mogas: https://www.lycoming.com/content/unleaded-fuels-part-2
• Avgas by Any Other Name is…Avgas: https://www.lycoming.com/content/unleaded-fuels-part-3