[Headline: Still pushing the limits]
Ever since I saw my first micro RC airplane fly while in college in the mid-1980s, I have been hooked on building and flying micros. Back then, if an RC model had a wingspan of approximately 30 inches, it was considered small. People were amazed when they watched a model of this size fly.
Throughout the years, my friends and I pushed the limits of how small we could build an aircraft. We soon had 13-inch wingspan Peanut Scale airplanes that used CO2 motors for power and a single-channel RC system for control. When LiPo batteries were introduced, we were able to shrink our airplanes even more. Six-inch wingspan 1/72-scale models? No problem!
The challenge of seeing how small we can go has always been fun to pursue. We were limited only by technology and our imaginations. Today, my friends and I are still pushing the limits on how small we can build!
Martin Newell’s Bipe 50
Master micro RC modeler Martin Newell designed an amazing less-than-2-inch wingspan, two-channel biplane. The airplane is constructed of Durobatics foam and uses the Hip-Hop Rabbit receiver that Martin designed and built. In fact, he built every component on the airplane—including the motor!
The single-phase brushless motor swings a 0.9 x 0.8-inch carbon-fiber propeller. It is removable and slides out of a self-locking bracket so he can test it in other aircraft. The airplane weighs 1.3 grams ready to fly, with a 10 mAh LiPo cell. It has an external on-off switch and has external charging connectors that connect through a charging cradle. The airplane flies beautifully with a top speed of approximately 14 mph!
Red Tail P-51D
This is my latest super-small model design. The aircraft is a scaled-down version of my great-flying 1/48-scale Classroom P-51D design. I wanted to draw up some graphics for one of the Red Tail P-51s from the movie Red Tails. However, during my research for pictures and information on the P-51s used in the movie, I found that I liked the look of the full-scale P-51D Little Freddie that Freddie Hutchins flew with the 332nd Fighter Group.
Martin Newell gave me a beautifully made four-blade, carbon-fiber propeller at last year’s Northeast Electric Aircraft Technology (NEAT) Fair, so I had to build a model for it! My thoughts were to build a lightweight profile aircraft that would be a good flier.
The 1/100-scale Red Tail airplane is constructed of thin Durobatics foam, with a Hip-Hop Rabbit receiver for guidance. The airplane weighs 1.6 grams ready to fly with a 30 mAh LiPo and a 4.5-inch wingspan. It is only two channels—using rudder and throttle for control to save as much weight as possible. I used a 3.2mm motor from a Mini Vapor and made up a small gear drive for it.
Flight time is approximately 2 minutes, but the model is fun to fly. I enjoy doing close, low flybys with it!
What does it take to build a super-small micro RC model? You should have experience with building micro RC models from kits, or scratch-built models that use actuators for control. You also need some basic soldering skills to solder motor wires and actuators to the receiver. For some people, soldering small wires to a tiny receiver can be the most challenging part of the build. With a little practice and the right tools, soldering gets easier.
You need a good soldering iron with a thin bit to correctly do the job. I like Antex soldering irons. The company offers some high-quality irons and has a great selection of thin replacement bits. I currently use the Antex C15 15-watt iron for most of my work.
You also need to build a lightweight airframe. You can use thin contest balsa, or thin, lightweight foam for most construction. You can sand the balsa and foam down to cut the weight. I found that if you tape the balsa sheet or foam sheet to a piece of glass, you can easily sand it using a sanding block to reduce the material’s weight and thickness.
When it comes to commercially available small, lightweight components, Micro Flier Radio is your best source. Nick Leichty, the owner of the company, sells receivers, motors, actuators, propellers, and even lightweight batteries. He hand makes most of the products he sells.
The company sells the four-channel 115 mg Hip-Hop Rabbit receiver that I used in my 1/100-scale P-51. Nick will also build a tiny micro RC model for you if you have no interest in building your own!
DelTang (DT) sells a wonderful line of lightweight receivers that are compatible with Spektrum DSM2 transmitters. The Rx 46-1 receiver that the company sells weighs only 150 mg. BSD Micro RC is a distributor of the DT receiver line in the US.
Building a super-small micro RC model is challenging, fun, and rewarding. Give it a try![dingbat]
Micro Flier Radio
BSD Micro RC, LLC