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Oct 25, 2014, 09:08 AM
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Akin 45: a stretched super kinetic


Akin 45: a stretched super kinetic-see: https://www.hobbyking.com/hobbyking/s...dProduct=39853
the concept: i had the idea of using a hotliner, that is sort of a sailplane with clipped wings, to enhance its performance for soaring by enlarging its wing, as it has all that it takes to make a sailplane, including folding prop. got the super kinetic because has a good size and there is a spare wing available. the original wingspan is 32 inches (815 mm) and enlarged it to 45-1/2, and added some dihedral at the tips. 2 1.5mm cf rods at the sides near the nose to reinforce it, and also some carbon fiber veil to the nose and a piece of 2mm steel wire to the stab spar at the center. added area to the rudder. made an exhaust opening at the top of the canopy near the back to improve air flow to cool the motor and esc. i named it Akin 45 because it is a plane akin to the kinect, just longer wing. weight gain from extra wing is 34 grams, and wing area jumps from 130 to 194 sq in. weight without pack is 333 gr and with the 3x850 (72 gr) is 405. originally balanced at 34 mm with the pack at the back of the canopy compartment. no ailerons to start, although i left the servos at the tips for a future use if needed, but i don't expect so. (then i will remove them and cover the slots). tested it and is erratic, as if the cg is too far forward, so i moved the pack to the under compartment an now balances at 39 mm. now is more predictable, but still more tests are needed. it is fast, handles wind well, has a flat glide, and needs a good throw. i connected the rudder servo to aileron channel in the receiver so i can control rudder and elevator with the right hand and throw it with the left.
but is prone to break. what has broken so far: the motor mount, then the nose, then the fuselage amidship of the wing, then at the trailing edge of the wing, then amidship to the tail; then the front wing mount, then the rear wing mount, then the propeller hub, then the forward hook of the canopy, then the stabilator left side mount (even if it has a 3/32" wire running along), then the magnet that holds the canopy went loose. then the rear fitting that handles the stabilator came loose.
but the spinner cone has not. (but that's because i removed it).
so seems that now i can install it, eh?
and listen: am not complaining, just making a list of what has failed.
otherwise all is fine, thank you very much.
but never had a plane that so many things failed. not even close.
november 2: finished evaluation: removed servos, as are not usable for the kind of flying that i do, and sealed the gaps of the ailerons. this helped, and with the corrected cg (33%)the plane is fast but predictable. with the powerful motor it climbs vertical at high speed and 1/2 throttle. no tip stall, and flies fast. this means that can handle wind comfortably. and now has the spinner cone installed. it was a handful until found the right cg, and with all the parts that break kept me busy for awhile. but now is all set. problem with the design is that even if the wing sits on top of the fuselage, the tail is at same level, and it falls into the turbulence of the wing so is not as stable just for that. and if you add the flying tail, that is more sensitive, things get more complicated. that's why t tail-or gull dihedral make an airplane more stable.
Last edited by phil alvirez; Nov 04, 2014 at 06:21 PM.
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