Taranis Q X7 Buddy Box Setup

How to connect two FrSKY TaranisQ X7 radios for shared Instructor and Student control

The Instructor and Student radios are connected via the DSC sockets using a 3.5mm stereo audio cable (TRS style) 

Link to 3.5mm TRS cable

Note that RadioMaster radios require different cables. 3.5mm TRRS (Smart phone style) for "Old" radio and TS for "New" radios. Link to RadioMaster Trainer Cable information

FrSKY TaranisQ X7 trainer setup

Instructor radio (Master)

In the Model Setup page - Set Trainer Mode to Master/Jack

Mixer page (Adjust weights and expo as required. Best to be the same as in the Student radio)

Ch1 100 Ail E30

Ch2 100 Ele E30

Ch3 100 Thr

Ch4 100 Rud

In Special Functions page - Select a switch, Select TRAINER and STICKS and tick box

Bind Instructor radio to the receiver

In Radio Setup  > TRAINER page

Ail := 100 CH1

Ele := 100 CH2

Thr := 100 CH3

Rud := 100 CH4

Student Radio (Slave)

In the Model Setup page

Turn the Internal RF module OFF

Set Trainer to Slave/Jack

Ch Range 1 to 8 (just has to be more than 4)

Mixer Page (Adjust weights and expo as required)

Ch1 100 Ail E30

Ch2 100 Ele E30

Ch3 100 Thr

Ch4 100 Rud

Check direction of throws on both radios and adjust or invert channels as required

Simple 3 channel trainer

This design was inspired by a friend who wanted to take one of my "retired" planes to learn how to fly. So I gathered bits and pieces together and tried to come up with an easy to fly, crash proof trainer.

It only has rudder elevator and throttle, no ailerons. I wanted it to be as light as possible for slow and easy flight with a big energy absorbing nose and a tough fuselage.

The fuselage was shaped from a 50 x 100 x 370 block of XPS insulation foam and the tail planes are 8mm panels of the same foam. The boom is a Skyshark P4X 7.6mm tube.

The hotwire-cut 170mm clark y wing comes from rescued sections of the drowned Fokker (which now has new wings) Three x 360mm sections were glued together with the tips each raised 120mm. No spars are needed to hold the polyhedral due to the tape covering and large join surface area for gluing.

The nose is soft packing foam covered with tape and completely encases the 1300mAh Lipo battery.

The motor is the original Bixler 2, servos are cheap 9g HXTs, and it has a Plush 18A ESC and HobbyKing 3 channel receiver.

All up weight with the battery adds up to 550g, giving a slow continuous cruising flight time of over 30min.

This plane is very smooth and stable and with correct trim will fly hands off.

At this stage the nose, fuse and wings are almost bullet proof, but the tail planes are a bit too delicate. Thinner sheets of XPS foam are quite brittle so some kind of reinforcing is needed.  Both the elevator and rudder have cracked during the test flights so I have added a 0.5 x 3mm CF spars.

Might be better to use depron or corflute for the tail.

Dimensions

Flight video - motor slope soaring

Build video

UPDATE 30 March 2016 

After some tough flight testing by my dedicated student test pilot it became apparent that this tail

design was not crash proof enough.

So here is the new tougher tail design made from depron. The tail to boom join has extra foam fillets either side for more gluing area and to raise the elevator a little.

The new wing has more area and less polyhedral for smoother flight.

Update overview video

Tail build video

Dimensions for the updated tail design

MATERIALS

All my building materials and RC gear - http://newtonairlines.blogspot.com.au/2015/03/materials-and-links.html

Knauf XPS insulation foam - http://www.bunnings.com.au/our-range/building-hardware/building-construction/insulation/panels

Bulk Depron - http://www.tradewarehouse.com.au/more/depron-foam/white.html

Skyshark P4X spars - http://www.kitesandfunthings.com/ProductInfo.aspx?productid=SSP4XCAM0

New Stuff iron-on film - EZload laminate - http://www.neopostonline.com.au/lamination/ez-load-roll-film

Blank ID cards - Ebay http://www.ebay.com.au/usr/y2store?_trksid=p3984.m1439.l2754

BUILD VIDEOS

Hot wire cutting rig - https://www.youtube.com/watch?v=JIRzQO4F8ck

The Art of Hotwire - https://www.youtube.com/watch?v=_tt56xp2lQk

Pusher with polyhedral

I have never tried a 3 channel rudder elevator throttle plane so thought I'd give it a go using the orange slim wing and pusher fuselage.

RET planes need some wing dihedral to enable turns due to the lack of ailerons.

I fixed the ailerons in place and removed the servos. This simplifies the plane greatly, the wing is just a wing, no servos or wires, apart from rudder and elevator.

The CF spar was removed and a bent 200mm x 10mm diam ali tube inserted to set the dihedral. The wing extensions were hot glued in place at the desired polyhedral angle. The wing seems to be strong enough without a CF spar.

I increased the rudder area, but after the maiden reduced the throws for smoother control.

The 1500mm x 200mm wing and flying weight of 630g gives a wing loading of about 21 g/sq dm (7oz/sq ft) which is great for gliding and slow flying.

This plane is a delight to fly, so slow and steady. If I had started with something like this the learning process would have been much quicker. I can trim it to fly hands off in big lazy circles and it takes care of itself.

Wingspan - 1.5m (59")

Chord - 200mm (8")

Elevator servo - TGY 900 9g

Rudder servo - TGY 500 5g (stronger servo might be safer)

Motor - Turnigy 2822/14 1450kV

Prop - 7 x 4.5"

Airframe weight - 520g

Flying weight - 630g with 1300mAh LiPo (gives 20 min slow flying)

Sketchup Plans

Pusher trainer and test body

I made this plane so that my brother and his kids could have a go at flying RC planes, and as a test body for comparing different wings.

Actually this is the rebuild of that original plane which served it's purpose well, for one very windy but fun day.

It's a "pusher", meaning the motor is not on the nose but pushes from behind the wing. That means nose-in crashes won't end the flying session.

The tail boom is a 7.5 mm woven carbon fibre tube and the main body a 100mm x 60mm box.

The box needs to be tall enough so the prop clears the boom.

The rudder must be tall enough to get some of the airflow coming across the top of the wing. With a shorter rudder I experienced significant adverse yaw and poor directional tracking. Might be better with a tapered fuselage.

Motor mount is aluminium flat, bent up just past 90º and stuck on to a glued down ID card on top of the box.

Aileron servo lead extensions are taped to the rear sides of the box so wings can be easily swapped.








Multiple wing tie-down posts allow for different chord size wings to be mounted. The tie-down points are reinforced with pieces of ID card.

The tail boom is hot glued to the bottom of the body then depron strips glued either side of the tube for extra strength.

Tail servos are mounted on the tail.

I initially had the tail servos forward in the body with Gold-n-Rod push rods but these were chopped by the prop in a boom flexing hard landing.







The nose is soft parcel packing EPP covered in clear gaffer tape for impact absorbtion. It has an EPP tongue extending into the body to hold the battery. The battery can be moved right up into the nose or further back for balance.

I use this nose design in all my pusher and slope soarers now. Velcro tabs hold it in place.

Turnigy 2622/14 1450kV motor, 7x4.5 prop
500g without battery
Flying weight 610g with 1300mAh 3S

This video shows the maiden using a symmetrical 1.4m Armin wing