1953 | P53 Aeroscooter
We were not lacking ideas and projects, and the chance for a new aircraft came from De Bernardi. Gino began the project with my help and that of the draftsman Giovanni Sessa. A 1-seater, low-wing aircraft, with an 8-meter wingspan, weighing approximately 300 kg at takeoff, called P53; at first, the engine was a 25 hp two-stroke P25, later replaced with a 30 hp CNA-D2.
In De Bernardi’s intentions, the P53 had to be a hybrid between an aircraft and a gyrocopter[1]. The fuselage was designed so that the rotor could be installed in the upper part of the cockpit. In the takeoff, the rotor was blocked in a longitudinal position to be released as soon as the aircraft acquired speed.
We were not convinced of that solution, but we built the aircraft all the same and completed it without the rotor. In the shop of Via Tasso, the construction swiftly progressed, with the help of another former model aircraft maker, Marcello Pellecchia. We modified the fuselage several times to find the best solution. The tail boom consisted of a cone of Dural[2] with four round bulkheads, connected to the front part made of steel tubes. The wing was made of cantilever wood and the tail planes of tubes. Rolling the cone without the proper equipment was a problem that we solved with wooden rolls, while to rib the rudder sheet we built a sort of press with carpenter’s clamps. It was the first time that we were using a light alloy, another small step into the future.
Commander De Bernardi would come from Rome almost every week to watch our work that was progressing quite swiftly. We were waiting for the engine, about which we were rather doubtful. In fact, it was a 25 hp, 2-stroke P25 built in Milan by Ambrosini in a single original.
After completing the frame, we went through the static tests. Most of them were run by the engineer Simonetti from the RAI. The wing bending tests went well, but the torque tests had to be repeated due to some problems with the connections.
Everything was completed in February 1954 and we moved to Capodichino, in the usual hangar of the Aero Club to assemble the aircraft and run the test flights. We prepared the plane in a few days, but when we tried to start up the engine, the problems began. The Ambrosini P25 engine was very hard to start; it was very sensitive to the spark timing and had no starter motor. Gino and I would alternate in launching the propeller. Unfortunately, on the second start, the engine gave a strong kickback; the propeller hit the fingers of my right hand with violence. The pain was excruciating, my hand turned purple and swollen. I stayed home a couple of days with my hand bandaged, but I was soon up and running.
In the following days, we succeeded in improving the performance of the engine, which was still hard to start, and the aircraft was ready for testing. De Bernardi was jittery. The news of the first flight spread quickly and many journalists, attracted also by the name of the Commander, very popular, gathered at Capodichino to witness the first takeoff. We were anxious, anguished and worried as usual; feelings that would make us company for all our life.
De Bernardi left the strip quickly, ascended and performed the usual swift passages with various maneuvers. Then, he landed, but, instead of heading to the runway, landed with a yaw on the small junction before the hangar, among the cheering crowd.
The P53 was born: another airplane with the letter “P” had made its first flight.
After those flights, De Bernardi too realized that the engine wasn’t running properly. So, we needed to find another more reliable engine.
After a few days, De Bernardi called us from Rome to tell us that the solution could be the adaptation of a BMW 40 hp motorbike engine with two opposed pistons. Obviously, the engine needed some modifications and the installation of a gear unit to gear down the propeller; we commissioned this work to a specialized shop in Rome that would have taken a couple of months to complete. Moreover, the totally different engine required a new engine mount; so, we disassembled the front part of the fuselage and took it back to the shop in Via Tasso to make the necessary changes.
[1] The gyrocopter is an aircraft heavier than air with a rotating wing where, unlike the helicopter, the engine does not operate the main rotor, but generates a thrust forward, like in a plane. Therefore, the main rotor is not started by the engine, but remains in neutral, free to rotate with the force of the wind that hits it, and rotates in autorotation conditions.
[2] Dural is the trade name of one of the first types of quenched aluminum alloy. Its main components are copper, manganese and magnesium. Today, as an equivalent of this material, we commonly use the alloy type AA2024, consisting of 4.4% of copper, 1.5% of magnesium, 0.6% of manganese.
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