Wen-Mac Air Cobra on My three sons

Saw the My Three Sons episode featuring Robbie flying his Cessna in a contest against Roly's Wen Mac  P-39 Air Cobra.   In the Hobby shop, the owner advises Roly his .020  is only worth $1.50 trade in as it is obsolete.  This is an obvious plug by Wen-Mac to outclass Cox. Chick Hearn does the announcing at the contest, flown at a schoolyard ball diamond. It appears that they taught Robbie to fly as there are several clips of him flying his plane. The inverted flight sequences are merely a plane rigged to fly clockwise,  but not inverted.  Chick Hearn announced outside loops, vertical, and horizontal figure eights, none of which the scale plastic Wen-Mac planes could do. They seem to be flying on about 25 foot lines.  Robbie purposely crashes to allow his nemesis, Roly, to win the contests and a aeronautical scholarship. They used an actual clip of  Robbie crashing for the scene; it must have been from when he was practicing and lost line tension as you can see him move backwards to try and take the slack out of the lines right as his Cessna noses in. The hobby shop scenes  feature numerous Wen-mac models including  an SBD Dauntless and a fancy rotation display for the P-39 Air Cobra. One kid gets his glue bottle re-filled for a mere 8 cents, and Ed McMurry buys a 5 x 3 prop for$25.