Hi Beppe, it´s a nice and unusual design, i hope for you it flies well.
I´m no flying wing expert at all, but only a hobby flying wing aerodynamics.
I´m speechless about the flap divison. The Cobra- wing has the design an the back sweep of a less swept plank, but the flap division of a highly swept flying wing.
I wonder if we learn more about the design ideas and flight characteristics oft the Cobra-design with this flap division as we can read from beautiful ground-pictures and flight descriptions like
Best luck for the remaining flight testing and prying regards,
Uwe.
I have some experience with flying wings, I fly them on slope only, so, starting with the Zagi I went trough own designed PSS models such as X4 and Horten 229, published in Aufwind, I also designed X-wing wich actually is a model published on Flying Models, and SiGh in cooperation with Simone Nosi, an experimental F3F wing.
SiGh was published on RCSD the american in-line magazine.
Cobra was designed a lot of years ago when a leading italian producer asked for something new.It shoud have been a all-around model with no particular goal to reach other than to be pleasing and, hopefully, best selling.
The project was abandoned.
A friend of mine laminated two half wings that looked like to be a carbon treacherous weapon, so they are still there unused.
Last year my friends at Voloinpendio wanted to produce a little plank but when I showed them Cobra they fall in love with it, so moulds were CNC produced and prototype moulded.
So, the idea behind Cobra is almost told: originality, sexy courvaceous lines, all weather model.
Flying wings are tough to land on the slope, so I thought that the flap, placed mostly near CG could be used as butterfly to slow landing approach leaving elevons ( elevator-aileron ) to be completely free to do their work.
Test flight testified the ability of Cobra to fly thermals.......when found.
At launch the model showed to be nose heavy and required a fair amount of up trim, before to have it correctly trimmed it lost height and, as usual in this situation, no thermal was found, so I started flying around at no avail, to make a long story short, I regained launching height and choose to go out again as it looked like that conditions were turned good again.
I was wrong and the Cobra went even lower, I thermalled with little bank and with steep bank and the model flew both great, when I newly reached landing height I put it on the ground.
So I can't say how Cobra flies aerobatic or how fast it goes and if butterfly is working.
Leaving ailerons free from mix I had a mix on internal surfaces that lowers them just 1 degrees and they worked as do flap in a normal model: increased lift and a slight up trim.
More in the future.