Friday was quite an incredible day on several fronts. The massive snow storm, that pretty much shut down Toronto, ended up being a real blessing for us. With the evening soccer cancelled, we had an extra few hours to fly, giving us an excellent chance to make a strike for the prize. After many trimming flights, we started began testing the controls, but unfortunately upon full actuation the blades were thrown out of balance and a rotor ended up striking a line and snapping a spar. Of course this is the nature of flight testing, and the nature of any real challenge.
In the end, we are extremely please with the day. Having the extra time on the field allowed us to make small sequential modifications, changing only one variable at a time and amassing a massive amount of data / knowledge about the complex behaviour of this structure. This is now a game of understanding the details, and on Friday we learned a lot! In that sense we consider Friday a great success. This week we will be taking time to go through the video and data and make further modification to the structure, but below are a few quick points about what we”ve learned so far.
- The controls undoubtedly have enough authority to correct and reverse a substantial drift
- Full actuation of the controls can throw the blades out of balance, despite our best efforts to trim the blades and reduce control line friction
- Balance of the blades, and imbalances in the structure, and the drift of the helicopter are repeatable from flight to flight, and therefore correctable
- Tension in the bottom lines can drastically effect rotor-to-rotor interaction, which can amplify imbalances through dangerous constructive interference
This week we will be assembling the truss structure and suspending it in a way that we can properly measure in-flight deflections from rotor imbalances. Through a serious of tests we will try to determine the best way to arrange the bracing lines to maximize torsional stiffness, and minimize rotor-to-rotor interaction.