SD Creations www.sdcreations.co

SWITCHBLADE INSTRUCTION MANUAL

Things to keep in mind before you start

-Take care when unpacking and handling the model parts as some of the components are fragile, and especially the surface of the wings can be dented if grabbed with too much force.

-The wings use a foam core structure which is susceptible to solvents like thinnersand acetone and super glue. The green foam used in the winglets is not susceptible to solvents like the white XPS foam, so no problem with using super glue on them.

Please note that the hyperlinks will not work if this document is opened from the link provided and automatically viewed on your web browser. Youneed to download it first , right click and use the “open with” command to choose your web browser or PDF viewer. If you are using a cell phone to view this document, please download the Adobe Acrobat PDF viewer and also use the “open with” option if you want the hyperlinks to work. Or else simply scroll down to the correct topic.

Wing joining

Do not skip the wing assembly in order to rather glue the control horns and the launch peg prior to wing joining, as they will be in the way during the wing joining process while the wing is upside down on the workbench.

If you are using the extended nose pod as a wing skin joiner, skip the following steps and jump to the section on joining wings using the pod by clicking on the link. Joining wings using the pod

– Find a flat work surface. If the wings are placed inverted and pressure applied in the centre near the flap hinge line, this creates the correct anhedral angle due to the curvature of the airfoil like in the pic below:

Add more tape inside the radio equipment bay and on the leading edge to prepare for the bonding process.

The wings are joined together with the use of wing joiners and the cavity void filled with quickset epoxy.There are three carbon plates supplied as joiners, two for the front spar by the leading edge and one for the rear spar . They slot into place between the spar caps like this:

Start with the rear spar joiner. Mix enough epoxy glue to be able to void fill that area. Add epoxy glue to both sides of the joiner, slide it in-between the spars and let it set before working on the leading edge joiners. Weigh down by the flap hinge line so that it sets at the correct anhedral.

Once the epoxy has set, time to do the same for the leading edge spars. Tape up the leading edge so that you can place the wing vertically to allow the glue to run all the way top the leading edge, making for a hard point to take knocks on landing.

Skip the pod joining method and jump to gluing control horns by clicking on the link.

Glueing of Control Horns

Please view this video link of final assembly: https://youtu.be/DjA8FG-9GUI

Joining wings using the pod

– Find a flat work surface. If the wings are placed inverted and pressure applied in the centre near the flap hinge line, this creates the correct anhedral angle due to the curvature of the airfoil like in the pic below:

Join the wings together by bonding with 5 minute epoxy only on the foam section at the route while at the correct angle like the pic above. This is a non structural bond simply to be able to handle the wing during the pod bonding process.

Protect the section of the wings with masking tape, top and bottom along the edges of the pod skins

Lightly sand those areas under the pod in preparation for the bonding.

Apply some epoxy glue to only the top skins and spread it out so that it is approximately 1mm thick. Slide the pod in place and tape down the pod skins.

Once set, do the same for the bottom skin. The skin is flexible enough to fold back and keep in place with tape pulling from the nose while you apply glue.

Glueing of Control Horns

Please view this video link of final assembly: https://youtu.be/DjA8FG-9GUI

The smaller control horn is for the flaps, and the larger ones is for the elevons.

Add some epoxy on the horn and slot in place so that the hole aligns with the hinge.

Bend the wire 90 deg and fold it back on itself

Next step is to bend the wire at the correct location by the servo end. It is very important to have the servo horns in the correct position before bending the wire, and the control surfaces taped in the neutral position. For the elevons the horn should be facing 90deg to the servo, and for the flaps it should be slightly forward allowing for maximum downwards flap deflection , but also allowing for a little up for inverted flight.

The servos can be adjusted using your radio or one of these servo adjusters like below:

Here you can see that I have the adjustment for the flaps on level 2 of 5 facing towards the leading edge while the flaps are in neutral position.

Once all is correctly adjusted, cut off the excess wire and bend at 90 deg with thin long nose pliers exactly in line with the hole in the control horn. Then bend it over on itself.

You can also do fine adjustments by gluing in the servos as the last process with radio set up and linkages already done, and control surfaces taped in neutral position. If there is play in the linkages , void fill hole of the control horn of the servo with runny super glue, making VERY sure no excess glue runs into the push/pull wire sleeve. Gravity is your friend in this case, so orientate the airframe correctly and be careful.

Launch peg and winglets

Cut a 2mm wide slot on the marks provided at the launch peg location. Make sure not to go further towards the leading edge than indicated as the carbon fibre wraps from the spar around the front of the peg and along the side, and you don't want to weaken the structure by cutting into the carbon. Drill multiple 2mm holes along the mark and the dremel out the slot using these holes as guides.

Bond the launch peg and winglets in place using epoxy glue. Wipe off the excess glue before it hardens.

Recommended Radio Equipment

The receiver bay is wide and long , but the thickness is limited. The main objective in searching for a receiver is that the connectors are in-line with the receiver and not 90 deg. The receivers below are a good example.

Battery

The wing will balance with with a single cell lipo ranging from 7-20g with voltage booster to 5v. A square500ma pack will be ideal.

Servo

The control surface is small so any micro servo around 8mm thickness is fine. I have used inexpensive 0.8kg torque 5g analogue servos with success.

Balancing the glider

You will find the markings on the Leading Edge approximately mid way from the root and the tip. As the CG is further back than the trailing edge of the wing at the root, the best reference point is to run your forefinger of each hand along both leading edges while holding up the glider until the wing balances on the tip of your fingers.

This is a safe starting point, and you will find that the wing will still be stable in flight if it balances while running your fingers 15mm further along the leading edge towards the wing tips.

Control surface settings for different flight modes

Measurements are taken relative to the outer part of the flaps and the inner part of the elevons to the trailing edge of the wing:

In this example the maximum deflection is based on what ever the maximum output of the servo can give(usually 60 deg, 90 deg on max dual rates) using the recommended 6-7mm push rod connection from centre on the servo control horn. In this case for the Elevons it is around 7mm or more deflection from neutral at the reference point of the control surface , and the flaps should be able to go down about 40-45deg, and up a few mm(only for inverted flight).

No differential should be added for elevons, that is it should go up/down the same distance.

Flight Mode Deflections:

Launch- 2mm up on only left elevon if you are right handed, and only right elevon if you left handed. This sounds counter intuitive, but the anhedral makes the wing rotate away from you during launch(opposite of the common term of hooking the launch).Flaps are neutral during launch.

Speed – neutral Flaps and Elevons

Cruise- 5mm down Flap, neutral Elevons

Thermal- 7mm down Flap, neutral Elevons

UP/Down Elevator/Flap mix(snap flap)- With the latest V4 design, the foil used is thinner so it is important to mix flaps with elevator. Think of the nose of the glider like a canard configuration where the flaps are doing most of the work for pitch control. If you want to make the wing more responsive to pitch at lower speeds, you must mix in elevator to flap. Up elevator will mix in down Flaps and vice versa ,which helps in inverted flight withdown elevator and up flaps. I use 100% mix Elevator to Flap.

Options on how to set up your radio:

Here is a video link explaining radio gear setup :https://youtu.be/hvOwjhD2CXs

I like to set up my wing with a launch preset using a switch that I can control with my left hand(I launch with my right hand), as I would with all conventional DLG’s. My general flap setting is speed mode, elevons are neutral. When launch preset is activated via the switch, the left elevon goes up 2mm. Once Iam happy with the rotation angle after launch, I flick the switch to put the elevons into neutral. This means that it is not necessary for me to control the pitch of the glider at speed after rotation. As the speed bleeds off at the max height of the launch you would need to push down to get the glider horizontal and then go immediately into cruise mode.

I have linked my throttle stick to control the speed of the glider, that is when the stick is all the way down it will apply 7mm down (for thermal), and when the stick is all the way up the Flaps will be neutral(speed mode). So I only have a launch preset linked to a switch, and the throttle controls all possible flight modes. On launch I make sure my throttle is all the way up before flicking the switch and launching.

When I am landing and I want more flap deflection I switch on a landing switch which allows for maximum flap deflection still linked to the throttle.

Another option is to disable the throttle and use a 3 step switch for the different modes.

Flight Tests

If you are already familiar with discus launch, I would not hesitate to do a proper discus launch on my first attempt at trimming. The high speed of the launch will give one ample time through launch height to trim the wing. And if you have set up the glider as recommended all will be OK. Otherwise a powerful javelin throw(with thermal flap deflection) can be done by keeping the wing level and throwing gripping with your forefinger from a foam block that you can temporarily stick just in front of the hinge line.

Don’t be shy in putting power into your throw, the more speed the wing has the easier it will be to control and the more time you will have.

If there is a CG issue when you apply elevator input the glider rotates onto its tail too easily, then do notpanic and let it recover by itself before applying gentle elevator movements to regain control.

Tips for the Discus Launch Technique.

If you are unfamiliar with this, then please view this video which is very helpful in understanding the fundamentals:

https://youtu.be/BZKtCikjR7U

With this design, it is unlikely that you will release the wing too late after the discus rotation (the term ishooking) compared to conventional gliders as it naturally wants to release too early due to the peg location far back from the CG, and the anhedral adds adverse roll to the right. So you will find at the beginning if you are tentative that the wing veers to the right if you are right handed or to the left if you are left handed. To resolve this issue, simply hold on longer than usual and before release . Aim slightly up 30deg on the horizon on release.

If you are launching in strong wind, the trick is to hold the glider firmly with a straight arm facing into the wind. This will add to pitch stability during the rotation.

Landing Tips

An easy way to kill height and speed on approach is to slowly apply more and more up elevator while full flaps is deflected and the glider will comes down in a high drag nose up position. It feels counter intuitive to pull up instead of pushing down, but the flaps are small and the drag is not high so it is better to pull up. The glider will not tip stall and the stall is very gentle, so the glider comes down like a parachute.

If you want to catch the wing then make sure that you only grab it on the nose as you will most likely add finger dents on the wing.

If you miss your approach and if there is enough space, fly on and land level into the wind. If there is no space to land upwind, then rather land fast downwind with wings level instead of trying to do a full turn around and risk cart wheeling which will cause more damage than a high speed landing.