A project that took 20 years to see the light, the A1-C Juliet is a small acrobatic plane that can easily operate from difficult surfaces.
I designed the A1-C Juliet in the last century, as a new airframe for a small class .25 glow engine that was sitting unused on the shelf.
Little I knew at the time about aeronautical structure design, or even just model design. Therefore the first prototype was put together taking free inspiration from the early 3D Fun Fly planes. This kind of RC model started to appear on the market in the late nineties and was becoming popular among Italian enthusiasts.
The first attempt: A1-A
I started the first prototype with my father’s help. While not so bad in the general layout, it was way too heavy. Mainly because it had an all plywood front side and hardwood fuselage spars. Nevertheless, in the end, the construction was paused, and eventually abandoned, due to other events. In fact, I had to store away all the Rc planes stuff in my parents’ house. The prototype then spent years rotting in the attic.
The redesign: A1-B
About ten years later, I briefly took the model back from the dust trying to complete it to a flying condition.
Progress in electric models technology had now made the electric motor a valid alternative to glow even for aerobatic models. So I decided to convert the project into electric. Moreover, years of aeronautical studies gave me the tools to upgrade the models in pretty much all areas. As a result, I re-designed the whole fuselage in a much lighter balsa solution. The A1-B was born.
The original wing was restored and reinforced for better rigidity. But even with the added bracing it was not completely satisfactory. Therefore I drew a completely new wing with improved structure.
Unfortunately, after completing the second fuselage and set of wings, I had to move abroad. Once again, I packed everything for a long-term storage.
Finally in the air: The A1-C Juliet
Fast forward another ten years, I was back in Italy and in a semi-stable situation at work. It was time to recover the ancient remains and make a plan.
The situation was a bit worse than last time. The broken fuselage, the damaged wings, the stabilizers were gone and I found lots of other issues once I started to work on it. While I decided that the wings were damaged beyond repair, I tried to fix the fuselage. This required adding reinforcements to avoid breakdowns in the offended areas.
I had the chance to include several improvements while I was at it. This meant I was removing entire sections and building new ones. The result was a mostly new design, the third one (hence the “C” in the name). In particular, the wing-fuselage connection on the A1-C is completely new. I also gave the wings a new airfoil and slightly larger wingspan, removed the fuel tank hatch on the top fuselage and moved the servos in the tail. At the time I wasn’t sure about where to go flying with my RC planes. To be ready for everything, I reinforced the landing gear and its support plates. You can read more about the A1-C construction here.
The plane started to fly in the spring of 2018. yes, that is a 20 years long construction phase! In a few test flights, I found the correct settings. Then I just enjoyed the performances of the Juliet until a torque roll exit made at bit too low altitude brought me to the first accident.
The fall and the rise: The A1-C2 Update
The damage was limited. But I already had a few ideas to improve the design after the first weeks of flying the plane. So instead of patching up the broken parts, I went again for a partial reconstruction.
I replaced most of the front section, using a truss type construction. The engine cowl is now a few centimetres longer and reinforced with carbon fibre. But the main update is probably the wing-fuselage connection. Since I was only detaching them to load the batteries at the field, I concluded that join them permanently had several advantages. First, the structure gained strength and rigidity at the cost of no extra weight. Secondly, I could then open up a tunnel large enough to insert the battery through the canopy. All the control links and surfaces were then overhauled. With a better structure and smoother, more precise controls, The Juliet was once again ready to be covered.
As a finishing touch, the steerable tailwheel left its place to a carbon fibre tail skid that weights exactly half as much. Read more here.
End of the story (for now)
We named this “facelift” A1-C2 since it’s just a general update on the same design. In this configuration, the Juliet has logged over 20 flight hours. It has proven to be very reliable, even in extreme winds, stable as a 1mt 3D plane can be and a joy to fly. Flight times with a 3S, 2200mAh battery, are around 7/8 minutes of mixed aerobatics.
The Evolution: The A1-D
Although we still have plenty of ideas to improve further the A1-C, I am happy about where we are with it. Of course, in case any repair is needed in the future, there will be other minor updates. Bigger improvements are simply not practical on this 20 years old frame. The idea of a brand new evolved “Juliet”, was put in the drawer since I was focusing my efforts on developing the C18 (twin Beech semi-scale model, more here). I surely didn’t expect that that very project would lead me to design a new A1 plane to test structural solutions and materials. But since it happened, you can follow that new adventure on the A1-D Juliet II page.
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