P-38 Fowler Flaps

Community member Andres joined Josh to discuss his gigantic 8-foot-wingspan P-38 Fowler Flaps build.

The P-38 was made primarily with Dollar Tree Foam Board, with some wood in places to add shape and support.

Andres has put over 160 hours into building the P-38. The plane now has functioning inboard and outboard flaps set up. 

For the Fowler Flaps, Andres made it so one servo controls both the forward/backward movement and the up/down movement of the flap. 

Two arms on the outside come off of the servo on a torque rod and control the forward/backward motion. The shoulder arm in the middle controls the forward/backward motion.

Andres used music wire and servo arms that he cut off of servos combined with heat shrink to set up the complex arms.

The foam flap slides on a rail that is attached to the foam board to prevent it from binding. There’s also a small rod that allows for some flex in the flap movement to help prevent damage.
 

Andres put V bends in his servo wires so they would still work well even if they weren’t cut to the exact length. He also soldered the arms to the torque tube.

The outboard flap servos are hooked up with a servo arm and a large Z bend that matches the center of the servo arm and the outermost hole. There’s another torque rod CA’d and threaded to the servo arm that controls the outboard flap.

Andres created an algorithm for his Fowler Flaps, which you can download here!
 

Materials:

• Foam board
• Music wire
• Carbon fiber tube or very thick music wire
• Servo arms
• Heat shrink
• CA
• Thread
• Wood or other material to space the rails apart 

See more of Andres' airplane in the previous episode linked below.
Here's another clip of his plane flying at the indoor event:

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