JANUS - Aerobatic powered glider 40"

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A saw the video of the RedBull aerobatic glider team doing some exquisite flying and decided to  build something in those lines


The design had to have low sink rate, Low drag, 4 axis control & low wing loading.
Span : 1015mm
Root Cord : 155 mm
Tip Cord : 100 mm
Wing LE to Motor : 175 mm
Wing TE to Tailplane : 320 mm
Tailplane Span : 305 mm
Tailplane TC : 115 mm
Tailplane TC : 85 mm
Vertical surface ht : 130, Base width 115 mm

The wing is folded out of 3 mm depron. It is 3 mm depron top and bottom surface with a depron spar.. The thickness is 9%.. so the spar is is two 3 mm depron overlapped to 3/4 span, the outer part of the spar is just a single strip of 3 mm depron (3+3+3=9 mm.. which is 9% of 100 mm) . The top and bottom sheets were laminated with 45 micron laminating plastic film, the fold was grooved from the inner side and the the top part slowly folded over and glued onto the spar and in the TE. The aileron is just the top surface extended

The tail feathers are 3 mm foam laminated on both sides

The fuse is also built out of 3 mm foam. The lower portion was fibeglassed with thin FG for 3/4 of the length

Some features for lowering the drag are the, raked wing-tips which is attached after the wing is built and finished. The wing root fairing in the TE, this piece also happens to be the hatch for accessing the tail servos. The rear control wires (thread) exit the fuselage quite close to the control surfaces. The

Servos are connected to the tail surfaces (elevator and rudder) through push-pull strings. Ailerons are connected through pushrods (thin spring wire)

Electronics
1806 1800kv motor,12 am esc , 5X4 3 blade prop,  4 x 5 gm servos, 1500 mah 2S bty

All up wt comes to 270 gms.


                                                         A view of the folded airfoil





 Tail assembly. Note the push-pull control threads. Both  horizontal and vertical surfaces are 3 mm foam , laminated with lamination film





The wing without and with the wing tips addes




The wing root TE fillet. It is also the hatch for the servos. The wing is glued to the fuselage




Underside is fiberglassed . The hatch is for RX access and connection of the servos



The aircraft with some colours added.. looks good



A custom spinner added






The aircraft is very light (270gm) and with a wing area of  200 sq in, the wing loading is 6.8 oz/sq ft.. however realized that with the thin cord and the low speed the Re is also very low @ 60,000.. hence the airfoil does not add much to the lift .. and need to be careful of vicious stalls.   








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