build notes

 

   I designed the all my models models from a love of flying this type of model and as such I have built and flown several of each of these models over the last several years.  The aim of each design is to optimise the performance in the air and ease of use on the ground.  Materials, batteries and radio gear move on, the methods shown here are the ones that I do or have used on my own models over recent years.

  The build notes here are equally applicable for Saker, Harrier, Falcon and even Wyvern models.  There are clearly some differences in the models but the principals and approach suggested here will be a good starting point as you assemble your model.  There is no single way of assembling a model and you may feel that you have another- that you prefer.  If so- great and please share your ideas with the model flying community.

Wiring Loom

  I tend to make my own looms usually with 4x 1m servo extension leads.  This gives me with enough wiring and the servo ends I need, already fixed to the wires.  I used the multiplex green 6 pin connectors, with the male half fixed in the fuselage and the female half loose in the wings.   Once soldered and tested I suggest some epoxy or silicone over the connectors to make the loom more robust.  Once fitted in the fuselage there’s not much that can happen to your male connectors.   As I leave the female connectors loose in the wing I add 5 cm of heat shrink over the wire and connectors for extra support. 

  Give yourself enough slack so that the looms in the wing stick out far enough to be able to connect the loom halves before the wings get too close to the fuselage- it’s just easier that way and there’s less chance of the ends being pushed into the wing

Wings

  The wing assembly is very straight forward.  The horns are supplied separately, this gives you the opportunity to use commercial LDS systems if you wish.  Zhou will now be supplying 8 clevises per model, this gives you the option to use the raised horns supplied with an LDS system if you wish.

  I have used 2 and 3mm clevises with the supplied horns in the past- they all work very well. I know that I am getting old in my build techniques.  If you use clevises rather than LDS, it is likely that you will need to grind some of the clevis off to help it move freely- this is normal.  Once the servos and horns are in place.  Measure the distance so that the push rods are made up to the correct length.

  Here's an illustration from my old Artist instructions, with a nice illustration of the geometry.  I grind the flap and aileron clevises.

  The hole I cut in the wing for the aileron servo horn.

The clevis and horn fitted, ready to clean the wing down, a neat and effective way to fit the wing out.  This is a Falcon wing, the Harrier wing is slightly deeper at the hinge so the horn can be more flush.  If there is any slop in your fit out, a drop of thick Cyano and kicker will fill the gap.

  The holes in the wing for servos have are large enough to help fit ball-raced servos frames.  I’ve used King Max servos for all my Harrier's and Falcon models.  The fit is excellent and the servos have proved to be fast, reliable and slop free, I’m really happy with the servos.  These can be bought in the UK or through Ali Express.  The best 8mm servo I have found is the CHAservo HV85.  Solid as a rock and with ridiculous amounts of power- but at a price. 

 

  A neater looking job, using the LDS frames from servoramen but keeping the Clevis fixings.

LDS 

  I have started using LDS systems in all of my designs, the heavy duty LDS system from Servorama are good for 10mm servos but I don't like the 8mm servo frames that are best for the Wyvern.  So I have also used the Thomas Liu frames.

  Cutting the slot in the wiper can feel like a wide slot to cut out.  A little bit of tape to mark of how much to file away helps keep the wing skin neat.

  The LDS horn is long and means that you will end up cutting a slot in the flap sub-spar.  I tend to cut mine so the horn is pushed flush with the inside of the wing skin.  It's all a bit fiddly to get the horn in, attach push rod and make sure it's square and free, take it out and do it again with glue but it's worth it in the end.

 You can see that the horn and push rod have a top and bottom to get that pin as high as possible.

  A neat looking servo in situ.

  

Fuselage

  The fuselage assembly has been made very straight forward thanks to the moulded tray.  This holds the servos, switch and ballast tube.  It does not arrive fixed, making the cuts for the fittings is very simple and safe away from the rest of the fuselage.  It also makes threading those servo wires much more straight forward.  

  The Harrier fuselage is wide enough to take 2 12mm servos (such as the King max 2035) side by side.  As the Falcon is narrower it is a much tighter fit, I managed to do this in my first Falcon but it was very tight.

  The Ballast tube will slide in place once the servo tray is fixed, it's important that you plan the model's CG and know where the middle of the ballast tube is before you start gluing things in.  The ballast tube is provided slightly over sized, this is easy to cut to size.  Gluing a piece of dowel in at the back of the tube is also a very simple process.

  I fix the ballast tube in place using epoxy and chopped mat.  I have found that I need to make a hole for the lock nut to recess into.  This does mean that the servo tray is taking the weight of the ballast on landing, so make sure you are happy with it's fixing

  A final and possible over kill is to fit a block of wood between the ballast tube and top of the fuselage.

  Like all the models I have worked on with Zhou, the ballast tube takes 19mm chrome shower rail perfectly.  This gives over 1.2kg of lead ballast and has always been more than enough, although I have used up to 1.8kg of tungsten in the Harrier on the bigger days- Ballistic!

  The back of the fuselage is fully enclosed.  Before starting to fit the tail, the 5mm carbon rods need to be fitted and fixed.  The easiest way to do this is to drill through the fuselage so that the 5mm rods span the rear of the fuselage, this is the recommended way and the strongest.  This makes for an excellent tail fix as well as adding further strength to the fuselage.

   Be careful not to snag the push rods with the 5mm tail joiners.  The snake should slide by nicely when everything is together but taking the rods out to have another go after you have glued them in is not easy.

  The tails come without the elevator horns fitted.  My recommended way to fit the tail horns is to use a piece of 2mm push rod, the last one I used was 12cm long, with about 2cm poking out of the tail root.  Bend the end that goes inside the elevator as shown as this gives a mechanical link to the elevator sub spar.

   Bend and tape the elevator open enough to expose the inside- you will be able to see the sub spar.  Make a hole in the sub spar and at the root of the elevator to let the elevator horn through.  Some epoxy and micro balloons dribbled in to the elevator will fix the horn in place nicely, I have started using laminating epoxy, as it runs nicely along the sub spar.  Don't worry if a little resin extends further down the elevator sub spar.

  In order to Make things easier I have started to trim away some of the wiper.  This certainly makes fitting the elevator horn much easier.  As the elevator movement is 6-7mm there s more than enough left.

  The connectors for the clevis are made from brass tube.  Flatten 1 end and make a hole for the clevis you are planning to use ( a 1.5mm drill bit works for a 2mm clevis).

   You can see where a slot has to be cut in the fuselage to allow the push rods into the fuselage.

 

 The back of the Harrier is a tight fit but full size clevises can fit. You can see where I opened up the back of the fuselage slightly for the clevises to move more freely.  This helps you to make the the copper rods a little longer and help the elevator gearing on you servos.

   The copper tubes are first glued and then crimped onto the steel rods.

Tungsten sources

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Settings

Settings are a very personal thing with gliders but as a start point.

For the Saker model-

  These are still a work in progress and I will change them as I learn.  These can be cranked up for faster response with no danger in flight.

                I start with a CG of around 95 mm but the model can fly around this position.

                Aileron up 18 mm down 12 mm (at root) Flaps up 4 mm down 3 mm

                Flaps for breaks, over 45deg down slops her nicely

                Snap flap down 2mm across the wing

                Elevator up/down 5-7mm measured at the root. 25% rudder mix is a help

Thermal mode is simply 2mm flap and 1mm aileron down to generate some camber.  I tend to increase the aileron differential in this mode.

Falcon

  The CG I have been using is 91mm 

 Aileron up 14mm down 8mm (at root) Flaps up 3mm down 2mm (more for throwing her around)

                Flaps for breaks, over 45deg down slows her nicely

                Snap flap, I have 2 setting I am playing with, either 2 or 3mm across the wing, both coming in during the second half of the elevator stick.

                Elevator up/down 4/5mm measured at the root. 15% rudder mix is a help

For the Harrier model-

  These are still a work in progress and I will change them as I learn.  These can be cranked up for faster response with no danger in flight.

                Aileron up 20mm down 12mm (at root) Flaps up 4mm down 3mm

                Flaps for breaks, over 45deg down slops her nicely

                Snap flap down 2mm across the wing

                Elevator up/down 6-7mm measured at the root. 25% rudder mix is a help

 

CG  98-102mm

For the Willow 2 and SOR models my suggested settings are-

CG: 99mm. This is a ballance neutal point, if you are aiming for a more sweeping or EM turn then 96mm is a good place to start. 

Elevator- 5-6mm each way (measured at the root)
                    I do not use a large amont of snap flap for my flying style, no more than 2mm of flap with the ailerons mirroring the movement.

Aileron- Measured at the wing tip, 9mm up andf 5mm down.  I have the flaps mirroring at around 25% of the movement.  I have also started to mix in a little aileron/rudder mix to help keep the nose down.

CROW  Elevator 40% down
             The flaps can me set up to come 90degrees down very easily
              Ailerons 40% up



For the Willow 1 here are my suggested settings.

Cg- 100 to 105mm- Feel free to experiment with this but this is a good starting point.

Elevator-  8mm each way (measured at the root),
                                Snap flap 3-4mm (measured at the flap root and constant along the wing).

Aileron-  12mm up 8mm down (measured at the tip)- I've lately been using 9 up and 6 down for a smoother style.
                                Flap mix 4mm up 3mm down

CROW- Elevator 3mm down,
 Aileron 4mm up (measured at the tip),
Flaps anything 60degrees or more is very effective.

Launch/thermal mode- trailing edge 4-5mm down measured at the root and flat across the wing

Speed mode, 1-1.5mm up measured at the root flat across the wing (you may like to reduce the differential as this point as well

At the recent Champion of Champions race Adam Richardson had me increase the snap flap to over 6mm at the flap.  Worked great in theh turn and delivered 6th place.

If any Willow Pilots would like to send me their settings I’d love to hear from you and get an idea of the range of setting are out there.  The Willow’s characteristics make it great to experiment with different settings.

Ian