I had a problem with torsional flex in the vertical struts of the lower airframe causing the airframe as a whole to vibrate, but the biggest problem was that the motor, battery and receiver are up a little too high. When the helicopter gets light on it's frame just before it lifts off the surface, it wants to tip over. So, I at least know what to fix and adjust now. On a better note: the forward and aft tilt work well. I can hold the helicopter with 2 fingers and it will hover on it's "own", but some changes need to be made. In an effort to cut weight, I left out the lateral support struts on the vertical struts. They would have eliminated some of the torsional flex, but we learn from trial and error. Titanium has a bit more "spring flex to it and that also coulc have caused an issue. The video below is after the tether flight. During the tether flight I realized my "skevies" were showing so I left that clip out.....lol. The helicopter would lift up a bit and roll laterally. I have some work to do, but I'm not discouraged. As you can see in this video clip, the mast tilt seems to be ok.
Yeah, the mast angle forward/aft is ok with regard to the thrust vector. Small servo adjustment there. The shaft collar lock was a bit too close to the hub so there may have been a bit if dissymmetry of lift causing the lateral tendency to turn over. After I took it apart, I also noticed that the lower mast bearing housing came loose, so the mast torque was supported on one bearing. I should've used a carbon dowl pin with adhesive to lock it in to the frame. I'm already resketching the changes to the airframe, lowering the weight farther down on the airframe, laying the battery flat. And last but not least, the torsion flex. I over looked just how much torque affects this airframe. Rather than the airframe as a whole being affected by torque, the torque also transfered and was concentrated to the lower airframe at one point where that part of the frame attaches to the upper airframe. Since I removed the lateral support struts for the vertical struts, the torsion flex developed adding to the vibration. I got a few things to scratch my head over. More to follow.
Lower airframe has a wider foot print now for stability when the prototype gets light on it's frame. More pics of the adjusted airframe later this week.
finished the battery/receiver mount assembly, attached lower motor mount, started the upper bearing/motor mount. Video clip is the 2nd servo acutation, 1st servo after airframe changes. Correspondence w/ Williams Aerospace is steady, but only fixed wing UAS. They have great concepts.
I've noticed some things about some in the industry and in business in general. Most have no sense of self-less service; no regard for scarifice in the interest of the organization. Perhaps that is the issue with our economy. Out sourcing and jobs lost have all but crippled us.
My web site is down until I find another provider. I have found one and it should be up in a couple of weeks. Had surgery; in the process of recovering. Too many years in the Infantry. You can track the heo progress on you tube. Search "davh72able", morphing airframe helicopter" or "HIR"
Back from con-leave. They took the cast off yesterday, but I still walk like a pirate. Within 3 weeks I should have updates and hopefully a 2nd flight test. I'm behind, need new rotor blades, attach mast bearing and TR.
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