Frank's book was one of the first studies along with Circular Airflow that actually paid much attention to model sized aerodynamics and seriously looked at the world we free flighters and slower RC modelers fly in. His study of the forces and trimming requirements for a high powered free flight model was legendary stuff and is still required reading for any power free flight flyer that isn't all wound up in clockwork trim tabs.

He's also one of the first to seriously look at the curved flat plate airfoils used for indoor modelling.

It's one of those situations where us modellers had to fend for ourselves and as such I think it should be required reading for anyone that ventures into wingspans of under 5 feet and especially for folks looking at parkflyers and the like.

For example he showed that at "our" reynolds numbers the stall occurs at a far lower angle of attack than for full sized aircraft.