Simon Chaddock Posted March 19 Share Posted March 19 (edited) I have access to three 4000mAh 3s LiPo that look brand new. My biggest capacity battery a 2800mAh 3s is used in the Big Dragon 2 A Depron/printed lightweight pusher that is itself a rework of the original all Depron Big Dragon. As I still have both the CAD and stl files for its printed components the intention is, whilst retaining the same configuration, to modify the files to accept the slightly bigger 4000mAh 3s battery. The circular nose of the Big Dragon 2 is an "exact" fit for its battery so virtually all the pod files will need adjustment for the 4000mAh. To account for the extra weight a slightly more powerful motor and bigger prop (11x3.8 instead of 10x3.8) means the wing "pylon" will have to be slightly taller as well. The wing itself will be slightly bigger and stronger too. Anyway after many, about 24, hours printing and in some cases reprinting the 6 major components are now glued together with a slightly bigger, longer glass fibre boom. Not surprisingly it looks very similar to the Big Dragon 2 version. It has a 50A ESC inside the wing pylon that has built in cooling ducts. The 4000mAh battery is indeed a tight fit. It has been run at full power with a battery at just a storage charge and it delivered 254W at 25.3A. It blew a lot of air around the room! Now all I have to do is build its wing and tail. 😉 Edited March 19 by Simon Chaddock 1 Quote Link to comment Share on other sites More sharing options...
Simon Chaddock Posted March 29 Author Share Posted March 29 (edited) In between repairing the Stiletto and getting my hand in flying EDFs I have been slowly working on the Big Dragon 3. On the BD 2 I used a small servo to work each elevator. I did this as I originally intended to use then as rudders as well but never did. It made quite a neat installation as the 3.7g servos fitted flush with depth of the tail plane and being "Y" lead only one servo wire went down inside the boom. On the BG3 3 I chose a single bigger servo to work both elevators. Each elevator has its own link rod to allow for the odd angles over the full travel. Each link rod goes to a separate hole in the servo arm. The L&R elevator horns are of different lengths so both elevators have the same travel. The near complete Big Dragon 3. The wing is actually a "spare" I built for the BG 2 some time ago. Only the Rx and some servo wiring still to go. The BG 3's "party piece" is the two section "fishing rod" boom is collapsible for storage. Longer than BG 2 and with a slightly greater 57" span but with 43% bigger battery it will be about 150g heavier at close to 900g. Not really Intended to be a powered glider but more of a reliable "fun fly". If it performs anything like BG 2 it should have an impressive climb and cruise endurance. Edited March 29 by Simon Chaddock 1 Quote Link to comment Share on other sites More sharing options...
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