Balsa, vac-form and long out of production.
One of many that went when Estes took over Sterling.
This kit like the Stearman crop duster for example, had a basis in rubber powered flight
but in the instructions you had options for free flight,
control line or radio control.
Thing was the age of the original plans came to light as
soon as you looked at the radio control part.
Forget servos and digital proportional control,
they hadn't even been invented for the RC hobby market when
this thing got designed as a model kit.
imagine just a box with a button, one click for right rudder,
two clicks for left and one more to centralise.
That's an oversimplification but you get the general idea
and what stood for a servo was more like a spring loaded solenoid.
Might well have been crude by today's standards but it worked.