The team is going to be back testing soon, trimming rotors and adjusting the structure prior to full flight tests!
Since Battle Mountain and Mythbusters, we've been laying the groundwork for our next steps in preparation for a return to flying Atlas. We plan to be flight-testing the full helicopter again by the first week of November. Some of the key concerns at the conclusion of our first testing session were:
-Rotor blade pairs were often out of trim/unbalanced
-Rotors produced uneven lift
-Controls required refinement/balancing/optimization
-Truss required re-alignment after many adjustments
Part of the team will be back testing at The Soccer Centre in the last week of October, hitting on these key points. We're building a test rig to measure and adjust the rotors independent of one another and the truss structure as a whole, allowing for more accurate measurements of balance and required power of each rotor pair. We'll also be able to adjust and trim the controls, finding the optimal neutral angle setting for minimum power and sufficient control authority over Atlas. Finally, independent of rotor trimming, we'll be able to set up the truss structure and adjust all the bracing lines to verify that the rotor axles are aligned correctly.
The first part of the new rig was finished on Tuesday. This is the “Dummy Rotor Axle”, and it will replicate the axle on the truss to which each rotor is usually attached. The rotor axle is free to slide up and away from the ground on a linear bearing rail, and will be loaded on top with large weights to simulate 1/4 the mass of the full helicopter. The Dummy Axle and Base/Rail required lots of mill work, lathing, and welding, but with the help of Terry Cleland (of Cleland Instruments) we were able to machine and assemble it start-to-finish in two days. Fun work overall!
Cameron turns an aluminum part of the Dummy Rotor Axle on the lathe at Cleland Instruments' shop.
Todd with the completed rotor test stand.
We still need to finish the rig that will support and stabilize the drivetrain frame, but this will be largely comprised of off-the-shelf items we have hanging around, and shouldn't be much trouble. We're excited to get back into the thick of it!