Build It: Tiny Tim

Written by Tim Bailiff Go RC with this economical glider Construction As seen in the Summer 2018 issue of Park Pilot.

Specifications:

Type: Free Flight conversion Wingspan: 8 inches Weight: 0.4 ounces

Tiny Tim Material List

>> #25-1 Guillow’s glider or equivalent >> Parkzone Mini Vapor receiver unit and pushrods (PKZU1261) >> 6 mm x 15 mm brushed 15,000 Kv coreless motor or equivalent >> 30 mm four-blade propeller (fits 0.8 mm motor shaft) >> Venom Fly 70 mAh 1S LiPo battery (or similar) >> (2) GWS 9/16 lightweight foam wheels >> 3.5-inch piece of .032 music wire >> Blenderm medical tape >> Thin and medium CA glue and kicker >> Five-minute epoxy >> (2) #0 x 1 pan-head screws >> Two-pin male micro motor connector >> 1.25 x 1 x 1/32 balsa sheet >> 1 x 1 x 1/32 plywood

Construction

>> After an enjoyable morning of flying, I returned home to my workshop, where I found myself thinking about building a little something. You see, I’ve always been fascinated with small RC airplanes, and what I came up with is a particularly unique little aircraft. In fact, it has the distinction of being not only an RC conversion, but also the smallest RC model I’ve designed and built to date. It’s super easy to build and loads of fun to fly. The airplane goes together rapidly because it starts as a simple 8-inch slide-together balsa glider. I paired it with the micro electronics that were used in the ParkZone Mini Vapor (horizonhobby.com/parkzone). For the powerplant, I chose a tiny brushed, coreless motor and propeller combination similar to those used in the Blade Inductrix (bladehelis.com/Inductrix) quadcopter.

The Mini Vapor receiver unit is installed using a single plywood mount.

The result is a surprisingly robust, spirited little airplane. It is guaranteed fun for even the most experienced fliers. This one will keep you on your toes! Because it was nearly the holidays when I was designing it, I couldn’t help but be influenced by Charles Dickens’ A Christmas Carol. Keeping that and my own name in mind, I humbly present to you the Tiny Tim. I suggest that you read the entire article before you assemble your materials or begin to build. You might find that you already have much of what you need. If you need to purchase anything, visit your local hobby retailer before taking your business elsewhere. I’m sure it would be appreciated.

Carbon-fiber pushrods, wire pushrod ends, and heat-shrink tubing connect the receiver to the control surfaces.

If you cannot source what you need locally, the internet is always a good option. Feel free to substitute anything along the way. This tiny airplane only weighs 0.4 ounces with the battery, so remember to keep things lightweight and pay attention to the recommended center of gravity. The airborne electronics came from a ParkZone Mini Vapor. I had previously purchased a Mini Vapor fuselage with an electronics replacement package. The fuselage within came equipped with a tiny, all-in-one receiver unit that included a DSM2 receiver, two linear servos, and a brushed ESC. This package also included carbon-fiber pushrods, wire pushrod ends, and heat-shrink tubing. All of these parts were usable, but electronics and pushrods harvested from a used or damaged Mini Vapor will work as well.

The Tiny Tim motor installation detail shows right thrust and the landing gear installed.

I strongly recommend that you fly over grass. Tiny Tim’s small size and speed practically guarantee that there will be a few bumps along the way. Because of its diminutive size, the airplane has little mass, which equates to a correspondingly low “crunch factor.” I have had my Tiny Tim dive full speed into a grassy field, and it simply bounced. Now, I don’t recommend you make a habit of doing that, but grass ensures that the airplane will survive your learning curve. If you haven’t had much stick time, you might also consider asking a seasoned flying buddy to give you a hand when flying it over grass! The tiny Guillow’s #25-1 model (guillowgliders.com) I chose to use was a “free giveaway” glider. Our community hosts a number of fairs and events. Perhaps yours does too. During one such gathering, our local newspaper gave away some small balsa gliders with its name printed on the tiny wings. I’ve seen these gliders sold online at places such as the Guillow’s website. Although frequently sold in large lots, I’ve seen them offered in smaller quantities as well. Takeoffs are possible, but they are tricky and require some practice. I recommend that you hand launch your little airplane, especially for your first few flights. A calm morning would be best, but your Tiny Tim will fly nicely in a light breeze as well.

A Venom 70 mAh 1S LiPo battery powers the Tiny Tim and is held in place with blue painter’s tape.

When you are cleared for takeoff, face into the wind and advance the throttle to full. Now briskly launch your Tiny Tim up at roughly 30°. If balanced properly, your little model will accelerate and climb out smoothly. Continue climbing until your airplane has ascended to a comfortable height for you. Now throttle back a little but keep a good amount of power in. You will discover that Tiny Tim flies best if you keep its speed up. Finally, trim it for level flight. Get the feel of your airplane by trying a few turns. Go easy with the controls. Remember, sometimes less is more. It’s fun to fly, isn’t it? Because of the little airplane’s size, I find it advisable to keep it in fairly close. It’s pretty quick, so my flights usually involve lots of turns. After you get a little stick time, you’ll find from level flight that full up-elevator and full rudder will produce the cutest little snap rolls. If you take it up a little higher, try a spin! Stuff happens pretty fast with this little airplane. Try not to overcontrol during your recovery, but should things ever get out of control and you suddenly find yourself heading into the turf, fear not. Simply cut the power and hang on. Tiny Tim is quite resilient! I have yet to break anything, including my propeller. As I noted, it simply bounces on grass. When it’s time to land, decrease the throttle slightly to start your decent. Remember, Tiny Tim isn’t much of a glider anymore. During your approach, keep your speed up and use power to adjust your height. Just before touchdown, start your flair and then chop the throttle all the way off. Down and done. How fun was that?