I,ve got a much used Ring Jr. that currently flies on a Fox .15 Schneurle, 52'X.012 lines and an 8X4 prop. Pretty fast bust good for sport flying, just loops, lazy 8s, wingovers and low inverted ( love clipping the grass with a beater plane! )

It has flown in the past with a Fox .15X, OS .10, and when it was new and a bit lighter ( before numerous repairs) it was a great flier with a Cox Medallion .09. The Medallion engines have always been a bit more user friendly for me, and still turn up pretty good.

When using the smaller engines I flew it on a bit shorter lines, about 49'. I acidently hooked it up to a pair of 35' X .008 one time, and decided to try it- exciting for a bit - but I got dizzy and dumped it.

One thing to remeber if you do build it - use a longer elevator horn than the one in the kit and keep the travel down to about 1/2' each way. Too much travel and you can practically stop the plane in mid- air with full up elevator.