Seems like development of unpowered fixed-wing thermal and slope soarers has taken a backseat after the initial enticements posted in other threads here:
http://diydrones.com/video/autonomous-thermal-hunting-with-the-thermopilot-v5
http://diydrones.com/photo/thermopilot-project-phase-3-tested-with-apm2560
http://diydrones.com/video/the-thermopilot-project-a-thermal-hunter-glider-drone-by-jean
http://diydrones.com/video/cross-country-soaring-with-the-thermopilot-v5
Was really beginning to take a liking to the idea of an APM-equipped glider. An aero-towed configuration seems the easiest autonomous flight regime from the valley to mountain-top and return that is common here in the Eastern Himalayas. View from the airstrip:
The ridges and peaks where we RC and paraglide:
Buddies are doing group/club build of Junkers Ju-52 IC-trimotor with aero-towing capability. To collaborate on the TanteJu's maiden, started work a couple of weeks ago on an individual build of a semi-scale DFS-230 glider that will be lofted above by the tow tug. Work on the 1.64-meter WS glider started a couple of weeks ago, traditional stick and tissue construction with composite spars and reinforcements.
Since the original full-scale DFS-230 carried almost a dozen passengers, there is sufficient volume for a full avionics suite devoid of ESC, motor, etc. Due to its historical significance, am building the DoppelSitzer version with enlarged canopy and tandem cockpit. Of all the gliders from that era, the DFS-230 has the best sailplane qualities and numerous threads in forums from different continents have in-depth build logs.
RC will be UHF LRS either open source or TS. Telemetry is via RFD900 radio modems, the first hardware to be installed onboard.
Fuselage came within design weight so I have more reinforcements to play with in case of inevitable uncontrolled descent into terrain:
Integrating individual components of the avionics suite take priority of the servos and other RC hardware. Test-bench through-hole linear regulators being replaced by SMT PSU distribution bus. 900MHz VP and CP patch diversity antennas will be installed in vertical and horizontal stabilators:
The single 30-cm tubing supplied with airspeed sensor is just long enough to connect one pitot tube to the transducer. Guess I'll have to wait for next delivery to arrive from jdrones or scrounge local suppliers for the tubing:
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Comments
The 14AWG and XTC is way overkill for an unpowered glider; first to be replaced with lighter and more compact power distribution bus.
First long failsafe while under tow will be actuation of towline release mechanism.
Oh I forgot. While captive under aero-tow flight regime due to the kinetics of the towline, in RC world, we only use rudder. Only in RTL will the DFS-230 make use of ailerons also.
@ Gary. It is for RC, paragliding. Next is FPV after this record monsoon. Paragliding flights are pretty limited to short VFR distances during monsoon season here now before rains and or clouds set in.
@ Trung: Thanks. You're right about "modern composite military UAV" clones here. But IIRC the DFS-230 was one of the first military UAVs in the Mistletoe configuration. No, autonomous thermal hunting is not part of the plan as no one has come up with the robust code for it. The original DFS-230 has pretty impressive gliding qualities judging from the documented polars:
This is flight route and elevation profile of above video. APM-enabled maiden with similar waypoints and altitudes will give me better understanding of this build's gliding capability. Airspeed sensor will control minimum speeds: descend to maintain gliding speed.
Amazing backdrop for flying - or anything else for that matter!
Cool to see this type of build here. Most projects here tend to emulate modern composite military UAVs.
How about more details on your mission goals. Where does APM come into play? You posted some links to autonomous thermal hunting. Is that part of the plan?
What a place to fly! A real build to boot. Most certainly subscribed.