To my knowledge all model-sized aircraft engines - gas/glow/2-stroke/4-stroke - require oil mix in the fuel. Whether castor, synthetic or 2-cycle chainsaw oil. A sump & splash system won't work in an aircraft and a oil pump system would be heavy and expensive.

PS - your link to Dave Platt is to the index of all models. Not a apecific one. At least for me. HEY! I'm one of the "one or two" among hundreds of visitors that cannot see the menu selections at his website per his help link.