Twin Boom Easystar

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Multiplex Cularis

I now have the new Cularis from Multiplex. This seems to be a lovely glider, and the kit has some real nice touches to it. I'll be running an AXI 2826/10 brushless motor and a 12x6 folding prop. I'll be using HS 56 servo's for the Aileron's and flaps, and HS 81 servo's for the Rudder and Elevator.
More info coming soon.

Built up from three Easystars, the Twin Boom EZ should be a great performer with its 74" wingspan and Feigao B40-10S brushless motor. I've installed ailerons/flaperons and enlarged both rudders. I use two Y cables to work both rudder servo's and both elevator servo's, and an RX channel for each aileron so that flaperons can be used. Her AUW is just over 1700g, which isn't light, but this will be with an onboard camera. I'm looking into the new Panasonic HDC-SD5 HD camcorder to provide onboard video.

There's probably over 35 hours of work gone into this Easystar, which will be the most I've ever done on a custom EZ. I'm using a Graupner Carbon 13x7 folding prop which not only looks superb, but will fold out of the way when I come into land, as the prop passes the bottom of the fuselage by around 2".

Rudders I enlarged both rudders and inserted nylon hinges which were CA'd in place. I first drew a straight line around 1/2" back from the moulded hinge line and around 2" from the top. Using a sharp modelling knife, I followed the line and cut the new section out. I then cut away the edge of the foam on both sides to allow fee movement of the new rudder. I cut two slots using a sharp knife and inserted two nylon hinges, these were secured using a couple of drops of thin CA. I reinforced the lower edge with a small piece of thin balsa wood.
Ailerons/Flaperons I decided to make the ailerons 16" long by 35mm deep. I cut out the aileron using a sharp knife and cut away some of the foam along the edge of the aileron and wing to allow for free movement. I cut slots on each aileron and wing to insert seven nylon hinges, these were secured with thin CA. I cut a 2mm carbon rod the width of the aileron and glued this to the underside using 5min epoxy. I used this to make sure that there wasn't any flex in the ailerons. I've kept the travel to around 10mm in each direction.
Elevator The elevator was a little tricky, but came out pretty well. Once I knew the distance between both booms, I placed all three elevators on the floor and placed them over each other, so that I could mark where I had to cut them. Once they were cut, I glued them together with 5min epoxy, and once dried, I placed a 4mm carbon rod on the underside along the whole length. Although I have two servo's working the elevator I still decided to firm it up by using a 2mm carbon rod. I've kept to the stock 5mm movement in each direction which I think should be ok, seeing how big the elevator is.
WINGSPAN LENGTH WEIGHT FUNCTIONS SERVO'S ESC MOTOR BATTERY PROP	1880mm 1150mm 1720g R/E/A/F/Throttle 6x Hitec HS-81 Jeti Advanced 70Amp Feigao B40-10S 4.4:1 3s1p 3700 lipo Graupner 13x7 folding

Motor and Prop
I'm running a Feigao B40-10S brushless motor with a 4.4:1 gearbox. It has a 4129KV rating, weighs 200g and is recommended for a 2-3s lipo and 13x8 prop. This motor pulls 44Amps @ 435W when used with a Graupner 13x7 carbon folding prop. I decided to use a folder because the tip of the prop passes the bottom of the fuselage by around 2", so could catch on the ground when landing. I secured the motor onto a balsa platform using Hysol 9462 adhesive. This glue is extremely strong and doesn't get affected by heat.

Inner wings and motor mount
Making the two inner wings took a little working out, but I managed to get it done ok. I got 2 left wings, and 2 right wings, and cut 7" from the root, keeping the cuts dead square. This allowed the new 1m wingspar to go through the whole length of the inner wings and into the usual amount on the two outer wings. I used 5min epoxy to secure the cut wings together, then placed some blue electrical tape over the join to keep things tidy.
The stock motor mount was cut in half, I then made a balsa platform for the motor to sit onto. This was glued in with epoxy.

Installing Aileron servo's Installing the aileron servo's is pretty straight forward. I measured 130mm from each wing root and marked around a HS-81 servo. I cut away the foam so that the servo would sit in the wing pretty snug, and secured with a drop of medium CA. I used the stock control horns for the ailerons but also used a backing plate to add extra strength.

Latest news - Flight report The Twin Boom Easystar has now been flown. My first impression was WOW, this is not only a great looking plane, it also flies and sounds superb. Launching was a breeze, I gave her 50% throttle, a good throw and she launched with zero trim needed. The Feigao motor and 13" prop has more than enough power, it pulls 45 Amps at WOT and generates 2.8kg of thrust. The AUW was just over 1700g, I added just over 150g to the nose to get the correct CG when using my 3s 2500mah lipo. The ailerons worked very well as did the flaperons. Landings were the same as the standard Easystar, she floated in gently with no bad habbits. More tests to follow.....

TB EZ Photos
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Twin Boom EZ Vids
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Take a look at the TB E'star before she fly's.

Maiden flight of the Twin Boom EZ. What a flyer.