R/C Remote Drop Mechanism
Carry a toy (or pizza) high in the air and drop it from your R/C plane or copter!
Written by Rick Schertle
Time Required: 1–2 Hours
Cost: $10–$15
RICK SCHERTLE teaches middle school in San Jose, Calif., and designed the Compressed Air Rockets for MAKE Volume 15 and the Rocket Glider for MAKE Volume 31. With his wife and kids, he loves all things that fly.
Materials
» Wooden craft stick, small aka popsicle stick
» Velcro tape, self-adhesive
» Zip ties, super thin: 8" (2) and 4" (3)
» Old bike inner tube, road bike size You only need a 1½" “slice.”
» Pencil cap eraser
» Servomotor, 9g such as Hobby King HXT900
» Servo extension cable, 12"–18" (optional) depending on your R/C aircraft
» Aluminum angle, 1½" legs, 1½" length
Tools
» Scissors
» Wire cutters
» Hot glue gun
» Drill and 
bit
» Hacksaw
» File
I’VE ALWAYS BEEN FASCINATED BY THINGS THAT FLY, and when Breck Baldwin showed how to build the “Towel” R/C Flying Wing in MAKE Volume 30, I was bitten by the flying bug again. We struck up a friendship at Maker Faire, and the flying wing, now known as the Flack (flying + hack), has been an absolute blast to fly. (Build it at makezine.com/projects or get the kit, Maker Shed item #MSFW1, makershed.com).
In MAKE Volume 31, I showed how to build a small but super fun balsa wood Folding-Wing Glider that’s rocketed into the air using a handheld rubber band catapult. At its apex, the wings pop open for a long and gentle glide down. (Build it at makezine.com/projects or get the Rocket Glider kit, Maker Shed #MKRS2).
Then I thought: How cool would it be to combine these two projects? With a drop mechanism, the toy could be carried high in the air and then released from the bottom of the powered plane!
Make the Drop
My drop mechanism is mounted to aluminum “angle iron” that’s attached to the bottom of the R/C plane with velcro. (This allows the drop mechanism to be harmlessly “torn” off in rough landings.) Attached to the angle iron is a servomotor with a lengthened servo arm, capped with a rubber pencil eraser that pinches the payload against the other side of the angle. The servo is connected to the R/C receiver, to a channel that typically controls retractable landing gear, so it moves its full range with the flip of a switch on my transmitter.
This mechanism can easily be modified for different planes and quadcopters to drop different things. We’ve dropped the Rocket Glider, a foam “delta dart” glider, plastic paratroopers, and bunches of brightly colored roto-copters made of cardstock (www.cambriansd.org/Page/1574).
If you’re dropping gliders, have a friend act as a spotter because once you release the glider, you need to keep flying the plane!
Once you get good at dropping, set up hula hoops as targets and come up with your own contests. Better yet, set up an autopilot system to drop your cargo at exact coordinates (think futuristic pizza delivery). 