I like going to RC swap meets because I can almost always find some rare and unusual models--my favorite kinds of flying machines! I'm pretty sure that sellers are also happy when I arrive. That is because I tend to be lured by the hopeless wrecks that no one else gives a second glance. I'm sort of like a cat lady for model airplanes. My most recent swap meet find is a good example.
Abused Wright Flyer
As I perused the aisles at the Sky Chiefs Swap Meet in Canandagua, New York, I spotted an awkward-looking biplane tucked under some larger models. Despite the significant dust and grime that covered the airplane, I recognized it as a Great Planes Wright Flyer. This little electric-powered park flyer was released about 15 years ago, near the 100th anniversary of the Wright brother's historic first flight. The model is a very rare find these days.
I ignored the filth and gave the airplane a quick inspection. While some foam components were damaged and others were missing, all of the plastic framework appeared to be present and in relatively good condition. I also noticed that it had both motors, the gearboxes, propellers, an Electronic Speed Control (ESC) and two Futaba micro servos. The servos alone made it worth the model's $10 price tag. I didn't even haggle.
My favorite genre of RC models to restore are those from the late 1990s and early 2000s. This was the time period when electric-powered models were just beginning to get popular. Most of the kits from this era were designed to perform well with relatively inefficient brushed motors and heavy NiCad batteries. There is often a significant improvement in performance when these planes are retrofitted with modern brushless motors and LiPo batteries. That was my intent for the Wright Flyer, although I did make some adjustments to this plan along the way.
It is difficult to overstate how grimy this model was when I brought it home. It was covered in a thick layer of dust resembling a cashmere sweater. The dust could not be simply blown away because it was tightly grasped by a mysterious sticky film on the airframe. My first job was to clean things up and see what I was really dealing with. That was the only way to decide if this model was worth restoring.
I went through a fair amount of Simple Green and more than a few paper towels before the Wright Flyer was free of its dirty shackles. Although the foam wings were discolored in numerous areas, they were structurally sound. A quick test revealed that all of the electronics worked as they should. I discovered some minor damage to the plastic frame, but it could be repaired. Of the vertical and horizontal stabilizers (two of each), only one piece was salvageable. I knew it would be easy, however, to recreate these simple parts. The answer was clear: I was GO for restoration!
I had to find a way to solidly mend the plastic frame. It was broken in a few spots at a critical area near the trailing edge of the top wing. I'm sure there are many valid tactics for such a repair, but I decided to try something new. I had recently been given a test sample of Beacon Adhesives Plastic and Composite Bonder and this seemed like a perfect opportunity to give it a try.
The bonder is a 2-part adhesive that must be mixed together. It comes in a dual syringe to help you dispense equal amounts of each part. But before mixing the glue, I cleaned the plastic components with isopropyl alcohol and scuffed the surface with a ScotchBrite pad. I then positioned the parts and used masking tape to hold them in place.
I dispensed a small amount of glue onto scrap cardboard and mixed the two parts with a craft stick. Beware, this is pretty stinky stuff! Once the glue was thoroughly blended, I used the craft stick to apply the mix to the broken areas of the frame and let it set overnight. All of the joints are still holding strong.
The Wright Flyer's wings are made of sheet foam with a thin, plastic veneer on the surface. I was unable to clean the stains off, so I decided to repaint them. Once the wings were removed from the frame, I hit them with a few light coats of spray paint. They soon looked as good as new.
My next chore was to reproduce the damaged and missing stabilizer surfaces. I used 2mm-thick Depron foam for these parts. The good horizontal stabilizer in the front made a perfect template for cutting the new part. I studied online photos of this model to estimate the proper size and shape for the twin vertical stabilizers in the rear. These are simple rectangles, so it did not take long to complete this job. I then painted all of the stabilizers with the same tan spray paint I used on the wings.
The wings and horizontal stabilizers slip into slots molded into the plastic frame. I reinstalled them, being careful to avoid scratching the fresh paint. The vertical stabilizers had to be glued to the frame. Foam-Tac adhesive worked perfectly for that job.
I briefly considered replacing the small brushed motors and gearboxes with modern brushless units. Doing so would have certainly improved the model's power and efficiency. However, legacy reviews of this model indicated that the stock system provided adequate power and long flight times. So it didn't make much financial sense to fix a problem that didn't exist. I decided to press forward using the brushed system, knowing that I can always upgrade it down the road.
The stock motors, gearboxes, and propellers were actually in pretty good shape. Even the old Electronic Speed Control (ESC) worked fine. I basically just cleaned all of the components and reassembled them. The gearboxes are mounted to two of the plastic wing struts. I noticed that the torque of the spinning propellers caused the struts to twist. They flexed so much, in fact, that I was concerned the props might hit the wing. I cured this by anchoring the struts with bracing wires made of polyester thread.
While the servos and control linkages worked fine, I felt this area was ripe for modernization. The model used two 9-gram micro servos. They are high-quality units and well matched to this application. My concern was that each servo actuated the corresponding control surfaces though overly-complex linkages. The aileron servo used two bellcranks and four pushrods with awkward bends in them. On the elevator side, a beefy wire joiner connected the right and left halves of the control surface. A long pushrod connected the joiner to the servo.
Clearly, the controls of the Wright Flyer would be much simpler if one servo was dedicated to each of the four control surfaces. I can understand why the model was set up the way it is. At the time the Wright Flyer was designed, 9-gram units were the smallest commonly available servos you could buy…and they were expensive. The complexity of the two-servo system was necessary to avoid the weight and price penalties of using four servos.
Here is where I reaped the benefits of technology. Itty-bitty servos are now common items and are typically priced at less than $10 each. I thought it made sense to rip out the old system and go with a four-servo configuration.
I dug through my servo bin and found two 4.3-gram servos as well as a pair of 4.4-gram units. The 4.3-gram servos fit nicely on the elevator. I used epoxy to attach them directly to the right and left sides of the foam surface. Short pushrods with Z-bends connect the servos to the control horns. This process was repeated when I connected the 4.4-gram servos to the ailerons on the bottom wing. The new setup is so much simpler and even a little bit lighter.
The Wright Flyer originally used a 7-cell 300mAh NiMH battery pack. A battery was not included with my swap meet purchase. That was okay because I knew that I would be upgrading to a newer LiPo battery anyway.
The much higher energy density of LiPo cells usually allows you to shave a lot of weight when upgrading from NiMH and NiCad batteries. This case was a little different. The NiMH battery was mounted at the extreme forward end of the Wright Flyer in order to balance the airplane correctly. So my new LiPo battery would have to be of equal weight to achieve the same balance point. Rather than being lighter, my new battery has much more capacity. Theoretically speaking the 2-cell 910mAh LiPo I chose should provide more than three times the flight duration of the original NiMH battery.
The voltage of the 2-cell LiPo battery is nearly equivalent to the original 7-cell NiMH, so I didn't have to make any accommodations with other parts of the power system (motors, gears, propellers). The only thing I had to consider is that the ESC is not LiPo-compatible. That does not mean that the ESC will not work with a LiPo. It just does not have an automatic cut-off feature that prevents excessive discharge of the battery. It's up to me to make sure I stop flying before the battery gets too low. I could add a separate battery alarm, but I don't think it's a big deal. I just land as soon as I notice a drop in power.
Back in the Air
My restored Wright Flyer weighs just over 12 ounces, which is slightly above the flying weight listed in the manual (still available online). I planned to hand-launch this model since there is no landing gear. Before my first flight, however, I discovered that it has sufficient power to slide along the strip of petromat on my RC club's runway. It will do a nice takeoff…even without wheels.
Despite its unorthodox construction, layout, and power system, this model flies quite normally. There is really nothing tricky about it. It flies slowly and very predictably. The plane also provides a striking profile in the sky. I always get a lot of comments when I fly it.
Aerobatics are not really part of the agenda with the Wright Flyer. I have been able to coax it though a few loops. It will even do a touch-and-go (slide-and-go?) on the petromat. But, most of my flights are spent cruising around at low level while enjoying the nostalgia of this cool little airplane.
This Wright Flyer was an unusual project for me. I usually gravitate towards first-generation electric models such as this with the goal of modernizing all of the electronics. This airplane reminded me that upgrading old-school electronics is not always necessary for good performance. I was able to realize some benefits by installing new servos and a LiPo battery. But the original motors and speed control are just fine.
All that the Wright Flyer truly needed was a good cleaning and some minor repairs. It ranks among my better swap meet finds. I'm happy that I was able to rescue this rare airplane and bring it back to life.
Terry is a freelance writer living in Buffalo, NY. Visit his website at TerryDunn.org and follow him on Twitter and Facebook. You can also hear Terry talk about RC hobbies as one of the hosts of the RC Roundtable podcast.