AM 40 (oz16160)

About this Plan

AM 40. Radio control powered sailplane model. Wingspan 309 cm, for electric with brushless motor.

Note the AM-40 (oz3883) design by Aldo Montanari was first published in 1946. This here is a later redrawn version for RC with electric power, published in Modellismo circa 2010.

Direct submission to Outerzone.

Update: Added article, thanks to Pit.

Quote (google-translated): "My friend Antonio Ghiotto had been insisting for a long time that I build a black-model conceived by the model airplane builders who were in vogue in the 40s and 50s. He had made many of these 'old timers' built with a wooden structure and paper or silk covering, for himself and others, and he showed me the drawings every time I went to visit him.

When we talked about old timers I always tried to gloss over it because most of the drawings I had seen did not satisfy me aesthetically. However, I had happened to see some aircraft soaring, which is conceptually a bit like seeing a feather cradled in the air and I was enchanted by this.

One fine day my friend Antonio, born in 1934, came to me to propose the construction of an electronic pantograph. Lipperli I took him for a madman and as with the old timers I glossed over the subject. In subsequent meetings he increasingly resumed these discussions, supporting his convictions with new documentation and saying that there were many examples on the Internet and that it shouldn't be that difficult to make one. One evening to make him happy I said to him - you start building the mechanics and then we'll see. I thought I had postponed the issue for a few months but after a week the prototype of the pantograph was ready. Not that it was great, but if you consider that the structure had been obtained at zero cost from the pieces of his old kitchen, in reality the result was more than satisfactory.

For the power electronics Antonio had made do by searching among the components recovered in the garage and by getting the board-axis from a friend of his while for the interface and the software to be loaded onto the PC I dedicated myself. After 2-3 months of self-study, internet consultations and various tests, on January 14, 2012 (a historic day for us not to forget) I finally cut our first rib on the CNC.

At this point I had to teach Antonio how to use the PC, mechanical drawing and the subsequent transfer to a file in machine language. We remained stuck at point 1, that is, how to use a PC, because I understood that from there to learning how to use mechanical drawing would have been too hard for him. I decided that I would dedicate myself to doing something that could satisfy both of us and I understood that the time had come to design an old timer, perhaps a glider.

I spent some time on the Internet while Antonio started rummaging through his magazines.

We immediately agreed on the fact that one of the most successful vintage gliders is the AM 40 designed by Eng. Aldo Montanari of Rome because it is one of the few designs with harmonious proportions, without unnecessary construction complications and where all the details match.

We redesigned our AM 40 on the PC with a wingspan of 3 m (in the original it is 3.5 m) adapting it to the materials available and easily found. The wing, with a single spar, was built with the D-box system and for the trailing edge we thought of a series of 2.5 mm balsa strips glued together vertically and then smoothed.

For the fuselage, which provides for the stabilizer support at half height of the fin with the classic brass tube and through duralumin spar, I insisted on a durable solution without play. We discussed this a lot and Antonio also involved his precious friend Valter Ricco. The solution found consisted of two aluminum tubes that support two ball bearings in the center of which passes a duralumin spar of diameter 5 mm. The axis of the bearings is ensured by the fact that the tubes fit one on top of the other with precision also giving the possibility of adapting the system to the thickness of the fin and thus obtaining a solution from my point of view exemplary..."

Supplementary file notes

Article.

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