White Swan

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 A slightly swept plank design.. a bow (something I was itching for a long time)





.>The idea was to keep the planform as a plank (wider speed range) but with very moderate sweep to move the MAC a bit behind while avoiding some of the cons of a swept planform. 
>Wanted to keep the TE straight, and the elevons not upto the edges to avoid unwanted separations. 
>The thinning out of the airfoil thickness, rounding of the wing tips, and the very slight washout (1.5 deg) for a efficient span wise lift distribution and reducing induced drag. ( Peter Wick's Plank design was a big help).
>The fuselage has been kept to a minimum with just a small pod in the front to house the electronics and boom at the back with the vertical fin

Dimensions


The wing is hotwired out of EPS..

Airfoil :  Root- phoenix 110% / P1 tip- phoenix 100% / Tip- phoenix 70%... There is a -1.5 degree washout between the P2 root and the tip

The wing has a built-up CF tow cap spar at 35% ..it does not have a separate compression web. The LE is also protected with CF tow laminated over the LE. The wing is covered with 50gsm FG at 45 degree weave. Certain places, the root, the LE and the tips have additional FG plys for reinforcement. It has a live FG hinge on the underside for the elevons.  The whole wing is vacuum bagged. At the centre the two wing are butt joined and has two ply joiners passing through the centre . It has a 2"  dihedral.  The (two) servos are fitted on the underside and covered with a 3D printed servo covers

A 45mm rectangular plug of the wing is removed from ahead of the spar. Into this slot, fits in a rectangular 250mm balsa box. The box is reinforced with CG and FG.. The motor attaches to the front of this box, the ESC is secured to the underside and covered with a FG cowl. The Rx and battery is housed in this hollow box and covered with a 3D printed canopy.  The undercarriage is a monowheel housed in a 3D printed strut cum wheel-pabt, glued to the underside of the wing .

The tail boom consists of a 12mm woven CF tube. The boom dismantles into two parts , with the rear part detachable for easy storage and transportation. The rear part has a fixed vertical fin attached to it. The fin is balsa FG composite with CF reinforcements 

Electronics : 2212 1400kv motor , 30A esc, modified 7.5" folding prop, 2X 12g servos, 1500mah bty

AUW : 680gms.. and with a wing area of 30.734 dm sq gives it a wing loading of 7.26oz/sq ft or 22gms/dm sq and a WCL of 3.99.. in the range of gliders

CG at 10.5cm from LE

Some pictures of the construction







A real beauty to fly and see .. fantastic glide ratio, climbs at 25% power, nice turning radius, and she is  faassst .. does not loose speed.. The first flight lasted about 8 mins and the bty (1500mah) was at 4.1v when it landed. She looks amazing in the sky.

Working on the trims and setting, and thermal handling .. contemplating  airbrakes in form of a drag rudder / spoiler  

Here is a video of a flight :   https://www.youtube.com/watch?v=8yf2AHSLwg8

Another flight video :  https://youtu.be/84bmmu9oqTA

Added airbrakes ..as the aircraft was fast and did not slow down adequately during finals, and considering the field limitations of the flying field.  It is operated by one servo and activated by a 3 position switch. It has two positions, full and half. The design keeps in mind that the tail boom is detachable for easy storage and transportation, and assembled at field. Also the edgeTx call outs are "brakes-on" for both full and half, and the "off" callout is "butterfly off" as "brakes off" sounded very similar to "brakes on".. (will try and get a different sounding .wav file).

Airbrake operation video :  https://www.youtube.com/shorts/SQCeUOJVRXE

Also added a bit of colour at the wing tips as spotting it was difficult on a grey cloudy day

Here are some pics showing the brakes 



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