Correx prototype Gee Bee Sportster

The plane is built from 3mm Correx or Coreflute.made from extruded polypropylene

 I've increased the wingspan to 900mm from alibopos Alistair Potter's original 840mmm plan in  FT article, Gee Bee Sportster - swappable. The fuselage remained the same. My wing has no dihedral only under-camber back 150mm from the tips.

The motor cover and ply mount  with battery pod slide over the fusilage and are secured by bamboo sticks with caps made from diabetes novamix pens. 

Pop off undercarriage fits into wing and is made from coat hanger wire and correx spats a combination of stiffness and flexibility 

The motor is a little  monster Turnigy D3542/4 1450KV Brushless Outrunner  with a 9x5.5 prop, bit of over kill but it is what I have.  Battery is a 2600 3s Turnigy ESC 60 amps RX LM 6Ch DSM2 Compatible Receiver. servos Emax with metal gears

Motor 130 grams and battery 250 grams ESC RX undercarriage take it to 840grams or there abouts.

Elevator and Rudder servos are mounted at rear, I find that having my pushrod wires and servos visible and as close as possible to the horns makes for easy pre flight checking, maintainance and feels more responsive.

The ailerons and elevator dont need hinges or tape just slice the undersideof the Correx along the fluting

I live in a very humid climate and find foam board turns to mush overtime. I have also built with Depron but it is relatively expensive and still marks easy.Correx looks a good option, cheap and very strong. The plane suprisingly due to savings in less structural supports and less glue including no need for a wing spar for this size wing, came in on par with a painted foam board build.  The Correx  doesn't mark or dent like foam board while building and biro lines just wipe off with spirit or turps. The surface can be painted with turps based spray cans once etch primed or covered with coloured tape or signage film. the correx glues up well with hot glue UHU Selleys Durabond Gorilla glue and super glue. I did a lot of testing with those glues

And if I ever get a hankering for the smell and noise of nitro then no problem as the Correx won't be effected by fuel.

Pinkie the ex Bixler pilot recovered from our club field

 Performance

The  plane now called Lola flew on the maiden beyond expectations incredibly fast rolls loops and climbs vertical with ease. I used the 900mm flat wing which I cant fault. It was very soggy on the field and grass was unmown so lets just say she is a handful on landing in the long grass I will install flaps if needed. The landings looked hard but the correx is very tough so no damage at all just few paint scratches on the wing leading edge. The day was cloudy with rain coming across periodically in squalls our wet season post cyclone Marcia. My video man was not around but next Monday with a mown strip at the field will be the go

I will try to get video of a full flight test  as soon as the sun returns

Update 18/03/2015 the day was sunny and we put Lola in the air with her new motor a Turnigy D3530/4 1100KV Brushless Outrunner  70grams with a 9x6 prop recommeded by e calc. the old motor Turnigy D3542/4 1450KV Brushless Outrunner  with a 9x5.5 prop was overkill regarding power and weight.

I have posted a first video

which does not have any footage of her loops rolls and flying inverted as the video cam telephoto jammed. My fault as we did a much too close and personal flyover of the intrepid camera man.

But I do hope you enjoy the little video took off on half throttle turned straight to the wind minimum trim required plenty of power flew straight and true and rounded up a few of her bigger brothers. Will post more if there is interest and when the cameraman recovers his nerves.

I have decided to build a scaled up a 60 inch version as there is much interest from club members

My thanks again to Alistair Potter Alibopo for the plans and advice.

my email barberr@squirrel.com.au

Ross Barber