XK A700A Sky Dancer

10 November 2016

Ouch! I drove the car over Sky Dancer last Sunday, my fault because I have no one to blame it on.

13 September 2016

Purchases on Sunday 11 September 2016. XK Sky Dancer, 3mm aluminium tubing, chuck glider.

Rotor brought in Mode 2, no camera no LED (designation A700B and A700C). I prefer mode 1, but mode 2 is fine with me for this glider.

Good for WLToys conversion?

Remove the canopy and ballbearing weight. Gouge the nose for battery space. Hotglue a WLToys receiver to the nose, over the battery space. Run wires through tubing or wire hoops along the fuselage to the rear and connect to hinged tail surfaces. Or maybe a single aileron.
Insert a power pod through the top and through the wing for a powered glider.

S-FHSS (Futaba) transmitter that came with the Sky Dancer.

 The LCD displayed 'L', the servos moved only a little bit. Spent quite some time trawling for information on how to increased the servo throw at the X-4 transmitter. The left gimbal can be depressed and this will alternate the dual rates from "L" to "H" and vice versa.

The Sky Dancer came with a 2S 300 mah battery. Rotor didn't have spares yet. Size of battery is about the same width as the 1S cell I have for the V979.

 This is the series adapter I made up to use 2 V979 cells.

I didn't crash, but the propeller went off-center on the second launch (same battery) after I set the mechanical trims. It was fiddly to push the propeller so that it stays relatively true to the axis. When I got it about right, I launched the third time and while flying, the propeller came off mid-flight. I managed to pick up the whole propeller assembly from the field.

The model can glide but it is not a floater. The glide ratio isn't too good. I thought a 2S brushed motor would be powerful but it wasn't so, perhaps it is because of the folding prop.

Daniel said I should use epoxy and not Loctite to glue the propeller to the motor shaft. Kasim said Loctite is fine as it won't attack the plastic. I used Loctite and as I tried to spin the propeller true to the axis, it broke off.

I found a propeller adapter that takes a 4 or 4.5" diameter prop (about the same as the broken propeller but much more blade area), but if I throttle all the way up, the motor cuts and I have to bring the throttle down to reset before I can apply throttle again. Maybe there's some sort of cut-off device at the brushed motor to prevent drawing too much current.

Banggood sells the folding propeller assembly, so an order was placed.

WLToys F929 F939 V911

31 October 2016 (PULL-PULL conversion)

Material:

• Plastic tubing from disposable cotton buds.
• Silicone tubing, 2mm?
• Paper clip
• Ice cream stick
• Superglue
• (Hot glue, pull strings)

Short length of ice cream stick, not exceeding 14mm, split into two unequal widths and superglued together in a cross fashion.
14mm length of plastic tubing superglued to the wider piece of ice cream stick.
Assemble two sets of pulleys, each from a short length of plastic tubing with two shorter lengths of tubing as stoppers.
Use short length of paper clip as a hinge, running throw both pulleys and centre tubing.

 View from the underside.

The twin pulley assembly can be mounted at the furthest end from the servo horns.

The twin pulley assembly can also be mounted next to the servo horns.

The twin pulley assembly can be hot glued in place so they can be removable.












Stringing the twin pulley assembly.

1. Length of pull string fixed at the rear control surface horn is threaded up through the furthest hole of the servo horn, round the horn, up through the nearest hole, round the horn again, down through the nearest hole, round the horn the third time, down through the furthest hole, around the pulley two times, add a dab of superglue to secure the string and back to the other side of the rear control surface horn.
2. Connect the pull string to the rear control surface horn, pass through a heat shrink sleeve, round the pulley twice, back to the rear control surface horn. Hook the z-bend of a short pushrod through the servo horn's hole, insert the straight end of the short pushrod through the sleeve. Heat/superglue to secure the pushrod against the pull string.

4 October 2016

If I epoxy a GWS type 5030 reverse propeller to fit over the WLToys propeller hub, I will have a pusher geared motor and prop. Two things to consider:

1. The shaft hole in the GWS propeller is smaller than the WLToys' propeller hub. I will have to drill a bigger hole and/or sand the shaft area. Or, could I thicken the white geared nylon shaft piece instead?
2. What could be a problem or a blessing, is that the GWS blade area is much bigger than the WLToys'. Trimming blade area and/or diameter is so not me!

I ordered fresh stock of receiver boards and the pinion motors a few weeks ago but they are still shown as Backorder on Banggood.

15 February 2016

100 pieces of 3mm diameter magnet is 5.9gram

The magnetic levitation experiment failed. The centre magnet is not needed because without it, the levitating magnet is still attracted to the centre position. Later found that others have tried and couldn't do it either (as far back as a century ago). The spinning action of the magnetic levitation toy is necessary for stability.



WLTOYS' F949 receiver block
Down elevator = right servo goes up








WLTOYS' F949 receiver block
Left aileron = left servo goes up












WLTOYS F929 F939 receiver block
Right rudder = right servo goes up
Down elevator = left servo goes up

WLTOYS	V911 Stick Direction	F929 F939	F949
Aileron	Left	NA	Left Servo Up
	Right	NA	Left Servo Down
Rudder	Left	Right Servo Down	NA
	Right	Right Servo Up	NA
Elevator	Push	Left Servo Down	Right Servo Down
	Pull	Left Servo Up	Right Servo Up

8 January 2016

Pull pull with single servo arm 

What if the bellcrank can be made light?

There's a 2mm slot between the two servos. The bellcrank support can be glued there. A slot at the other end of this support with enough room for two bellcranks to operate one atop the other and the axle glued across. The bellcranks will need to be accurate enough so they do not interfere with each other. One could be a thick bushing, the other would be a larger diameter spacer between the two bellcranks.

Pulley drums and spacers or bushings may be made by glueing coiled paper strips since it is so small and not much strength is required.

7 January 2016

Pull pull with single servo arm

This idea is to allow pull pull installation on WLToys' receiver board which has only single arm horns to the built in servos.

While it is possible to have single pushrods connected to bellcranks/levers and use that for pull pull, this is problematic: the slop, the complicity and the weight.

I came up with two methods of bypassing the bellcranks/levers and combining the ideas of these two methods, both servos of the WLToys' receiver board can be made to be used for pull pull installation with board mounted in either horizontal or vertical positions.

Method 1

1. With the receiver board mounted horizontally within a fuselage, the servo arm to be installed in the fore and aft orientation.
2. A pair of exit holes are made to the fuselage, they should be inlined with the servo horn's hole. There is some fore and aft movement when the horn is going through its paces, so the fuselage holes may positioned to be at the middle of this range, or, if that servo shall be used occationally only, at the line when the servo horn is at its mid position. There will alway be some kind of stretch and deformation so it is not a critical point. The exit holes are strengthened or bushed to have a radius towards the rear.
3. The pull strings are attached to the control horns and inserted through the fuselage exit holes and tied to the servo horn's hole.

Method 2

1. With the receiver board mounted vertically, the servo arms to be installed in the vertical orientation.
2. A pull string is attached to one control horn and the other pull string of the opposing control horn is threaded through an eyelet (or goes around a post) forward of the servo before returning to the same servo hole.

Hmm... They are all just variations of pulleys and loops aren't they? Even the bellcranks are also something like a limited pulley.

24 November 2015

I normally mount my receivers by gluing two/four strips of foam to it and then glue the foam to the model. With the Kirby Cadet, the servos are glued to the cutout. Today I thought of using Paulinda's Super Dough and polymer clay. They can be moulded to conform to the irregular receiver and then glued to both the receiver and model.
Nay, it is still easy to just glue foam strips, and lighter too. I haven't encountered any problem with the foam strips method.

16 November 2015

The 3 F929 939 receiver boards tested ok.

11 November 2015

Received 3 sets of geared prop, receiver board.

3 November 2015

A summary of mass:

• Weight of propeller, gear mount and motor is 7.6gm.
• Weight of receiver board is 5.2gm.
• 4 Channel airborne gear (200mah battery included) is 20.9gm.
• If only 3 channel, then 20.9-2.2 = 18.7gm.
• Therefore 200mah battery (V911 type) is 18.7-5.2-7.6 = 5.9gm

A summary of application:

• a failed Morane Saulnier (using a V911 type)
• a failed Yak 3
• a successful Yak 3 (larger)
• Cootie
• Chinook
• Kirby Cadet (using a burnt out esc receiver, F929 F939 type)

A summary of adaptation:

• a failed spinner made from Paulinda Superdough

5 May 2015

 3 sets of pinion geared motor, geared prop, spare prop, receiver all in one board.


















Propeller is 130mm, about 5". 2.2gm servo fits on the aileron port. Battery connector fits V911 batteries. 200mah in this case.









All 3 sets worked on my V911 transmitter.
Right aileron has the servo horn turn clockwise.
Right rudder has the servo horn turn anticlockwise.
Up elevator has the servo horn turn clockwise.

Weight of propeller, gear mount and motor is 7.6gm.




Weight of receiver board is 5.2gm.













4 Channel airborne gear (200mah battery included) is 20.9gm.

Junkers D1, Arup S2, Caproni Stipa

4 October 2016

An idea for a funfly version of a Stipa-Caproni: Flat sheets, large elevons and rudder (stubby wings) and it can do knife-edge and other 3D maneuvers?
Fuselage shall comprise 1 horizontal and 2 vertical pieces.
The top vertical piece includes the fin and the horizontal piece includes a pair of stubby wings and enlarged elevator.
The motor, receiver board, rudder servo and 1S battery are mounted to the horizontal piece.
The vertical pieces are braced to the horizontal piece with diagonal sheets.
Undercarriage structure comprises of a spar under the stubby wings, 2 struts cross at the bottom of the vertical piece which has a length of spar to spread the load. Heatshrink 2 soft wire pieces to the lower ends of the struts and glue on the wheel pants.

4 February 2016

How about a simple scale model of the Junkers D1? RET. Maybe I can print (laser print) stripes on paper, transfer stripes to coloured tissue, and use tissue as covering over foam model?
Simple sheet wings perhaps with single crank or rolled airfoil, or build up spar and cap strips over sheet wings?
Or maybe a cartoon scale type with deep fuselage (additional dihedral effect)?
Anyway, the dihedral, nose length and the tail areas have to be increased.



How about the Arup S2? Instead of 3 moving (+2 if tips are considered), let there be 2 elevons?
Sheet wing, foam fuselage bottom, paper fuselage top.





Maybe a ducted propeller scale model?
The rear tube of the Caproni Stipa shows to be parallel on the side view but tapered on the top view.
That could be represented by a foam tube, then slit V-cut at the top and bottom and join the edges together.
Instead of cones on cones or curved V cuts, how about just a simple straight tube, straight V-cuts for the tail end as described, then when that is done, 4 V-cuts in a X-manner at the nose and further division of V-cuts in between the previous V-cuts? Saves glue...
If cone on cone, instead of making all those calculation, just roll a rectangular piece of foam sheet into a cone, adjust, mark off, cut, glue.
I think RET would be simpler then 4-channel. The wings are so long, and they have bracing, so might as well give them dihedral.
As usual, increase fin/rudder and stabiliser/elevator.
Only thing is, if the WLToys propeller is to be inside the cowl, I think the model is going to be very big..., with wings beyond 30"? Make a cartoon version with stubby wings?

Dihedral Joints for Shallow Spars

9 September 2016

Some ideas for making dihedral joints for shallow spars. The last one is paired with the fuselage
:

1. Rely on wire. Length of spar with a steel wire heat shrinked at the dihedral joint. Crack and bend the spar. The wire holds the dihedral. Advantages: easy, accurate, adjustable. Disadvantage: it relies on steel wire, so it may be too ductile or springy and perhaps it will peel away from wing because there is not much gluing area.
2. Spar doubler. This is applicable to flat spars placed horizontally. A short piece is positioned against the spar at the dihedral joint. The two pieces are forced to a curve and then glued together forming a two layer ply. The main disadvantage is to fabricate a jig to hold the two pieces until the glue is set, there may also be some spring back.
3. Baseplate. In the Spar doubler, both pieces were bent, but in this application, the baseplate provides a flat compressive member so it has to be stronger than the spar. The spar is tied securely to the middle of the baseplate, small shims are added between the spar and the edges of the baseplate to form the dihedral angle. Baseplate can be substituted with a rod or tube, or a fuselage former.
4. Compression/tensile truss. Length of spar is cracked and glued to the underside (compressive truss) of a slim triangular former or a small rhombus former or a fuselage former. Gluing to the upperside (tensile truss) of a V-notched fuselage former is also possible.

Flying Flea

25 July 2016

Yesterday, a big predatory bird swooped and attacked the Flying Flea repeatedly. At one time, it caught the wing, but theFlea managed to escape. Its talons went through the starboard wing of the Flea. Everyone was excited at the spectacle.

 I think some tape would be fine to patch it up.

 

 

 

 

4 July 2016

I flew the Flying Flea yesterday after I hotglued the undercarriage wire into the slot, clipped the propeller short and made a battery connector to receive the spade type of batteries. At the field I discovered that the elevator is inverted when I used my WLToy's V911 transmitter, so the Flying Flea was flown in 2 channel mode: Throttle and Rudder. It flew easily to a great height using minimal throttle. On descent with throttle off, I can see it bobbing its nose slightly, indicating a slight stall condition on the front wing. There was a marked veering to the right, perhaps that got to do with the fact that the motor was spinning a smaller propeller?

The second flight ended prematurely when it dove to the ground and broke off the motor and the fin and rudder tore clear off the tail. It is fascinating that it requires such small amount of thrust and it appears that the front wings have high lift capability.

When I get my FS-i6 transmitter, I shall try again. All it now needs is some dabs of hotglue to re-secure the motor and tail.

4 January 2016

26 December 2015

Yes it flew!

It was over-powered. I think less than 1/3 throttle is required for level flight. I heard the propeller coming on and off intermittently at the lowest throttle I can maintain in order to reduce altitude.

Rudder control was ok, but the torque effect was significant. Even though I had set up exponential on the elevator, it was touchy to use elevator. To climb add throttle, to descent reduce throttle.  It was too windy to do meaningful flight adjustments.

25 December 2015

With the WLTOYS 8mm geared motor, a small cell but no undercarriage, the model weighed 35gm.
The undercarriage I had on the old Flea, constructed of CF rod running in aluminum tubing and commercial 1.5" wheels, weighs more than 7gm. That meant a 20% increase in weight if I use that.

The 7mm geared motor is much smaller and lighter than WLTOYS 8mm (which is a 8.5mm?). That meant a 10% reduction in weight if I use that. Also, the propeller is much smaller, and I will have less problem with trimming the torque.

The model is designed for 6-7mm geared motors, the thrust of the 7mm geared motor ought to be enough. However, I had the mount slotted to accept the 8mm and the 7mm mounting involves a square section rod so I hot glued the 8mm to the model. Looking for a reason for this decision, apart from the hassle of making a mount for the 7mm, I think 8mm is beneficial to the CG's position and I can keep the 7mm for something else.

The main wing was warped, so I raised a lower corner, mist and weighted the balsa wing. After 3 tries, the wing was corrected. I then used the remaining kit supplied 1mm CF rod and cut two lengths to the width of the main wing's ply pieces. They were inserted through the vertical ply wing mounts and superglued in placed. I think this is better and lighter than using the 4 missing kit supplied screws.

As for the undercarriage, I will leave them off for now, i.e., not going to make them, until the model had its flights. I superglued (Daiso's) small plastic tube to the hubs of the broken main gears of V977; they shall be the light weight wheels to replace the missing kit-supplied wheels.

Transmitter set up, model set up, cells charged, need to try in a big field on a calm day. I had to review how to bind and set up the Flysky transmitter.

21 December 2015

http://www.banggood.com/TY-Model-NO_7-292mm-Wingspan-Wood-Park-Flyer-RC-Airplane-KIT-p-1004972.html
T'is the season to be building, fly la la la lah, la fly la lah
From Banggood, a small laser cut balsa kit that looks a lot like the Flying Flea. The kit was selling for about $23.
Scary, the way it came in.






The balsa sheets were bagged and inside the folded corrugated board. (single edge razor blades not included)









Missing parts? Don't see the pair of wheels.










It looked ok.











The 3 sheets of balsa were complete, so was the ply piece. There're no wheels, and I don't think the wires/rods were all there.

Whatever it is, I started building.







I started by colouring the balsa sheet.


Time: 0:00







I drew the lines and coloured in with a red colour permanent marker.

Time: 0:11







Ah! The kit is missing 4 magnets! The missing magnets must have been 3mm diameter and perhaps only 1 or 2mm thick.
I have some 4mm magnets but they are too big for the formers. The awl cannot be used to enlarge the hole.

I would have saved some time if I had the 3mm magnets.



I enlarged the hole in the ply former with a round file and glued my 4mm x 3mm magnet into it.
Of course the former broke!
Then I assembled the 2 fuselage sides against the tray and glue them together. It is better to do it this way otherwise the ends might be mis-matched.

Time: 0:36



After the sides were glued to the frame, I found I needed to colour more balsa.

I painted the dashboard black and the top decking red.






They were glued to the fuselage and attention is now turned to the motor mount.

The motor mount had too small a slot to fit my WLTOYS 8mm motor.

Time: 1:43





The motor mount was marked out to receive the WLTOYS geared motor.










The motor mount was slotted ('dremel' type rotary tool rocks!) and drilled to accept the pins of the WLTOYS geared motor.

Time: 2:09







The motor mount was glued to the fuselage and I have to pre-colour yet another piece, this time the bottom of the nose before gluing the nose doublers and this nose bottom piece.








I assembled the pivot mount and glued it to the top of the fuselage. I pre-coloured the tail skid and glued it to the tail.


Time: 2:21






Work halted for the day, time for dinner.










I wrapped the pieces around a glass bottle, sprayed their top surfaces with water, some wood were used to spread the load of two rubber bands to prevent crushing of the moist surfaces, and left to dry in the morning sun.

Time: 2:30





When the pieces were dried, they were flattened out because I used a small glass bottle.

Drying and flattening time not included in the time taken to build this model.







The wings were assembled and glued 'in the air'.
Daiso's $2 5gm superglue rocks! And of course the precision of the parts were vital!

Time: 3:30







I marked out where the sewn hinges were to be. But I made the mistake by sewing from the other un-marked side. The kit is missing the plastic hinges in Banggood's photos.


Time: 3:45

It seems a dreaded task to mark out the locations, but actually it was very fast to do. 1 cm spacing.









The sewn hinge looked neat enough. it would have been faster, easier and neater if I had started the threading right on those pencil marks!


Time: 4:00

This is where the stale superglue can be used.












The hatch had two washers and these were attracted to the magnets in the fuselage.



Time: 4:10

The orange tube is the Daiso's superglue! Good product! Because it sticks well and it is cheap!











Another mistake I committed was to open up the rear slot for the rudder pushrod because I later decided that the front slot was more appropriate.



Time: 4:30












The kit is missing thin wires for the pushrods! The kit had enough carbon rod and heat shrink sleeve but no wire to make the connection. I had to use my own wires: a short length of thin music wire for the rudder horn connection and some lengths of thin flexible wire for the other 3 connections.

This took a long time to figure out and do.


Time: 5:00









Then I discovered that the motor wire was too short to connect to the board.

Flipping the WLTOYS receiver board didn't help, so the connections were fitted again and the receiver board was then hot glued in place. The sleeves were shrunk with a heated piece of paper clip.

Thang will give me an extension. He said he will give me a spare 7mm too.

Superglue was used throughout. I bought a fresh 5gm tube of cyanoacrylate from Daiso for $2.00. Good product! My stale balsa superglue (bought from model shop) didn't stick too well.












I still have to:

1. Wire up and hot glue the motor
2. Fixing the landing gear
3. Fixing the top wing. The kit is missing the 4 screws in Banggood's photo.

List of missing items in the kit:

1. 2 wheels
2. plastic hinges for the rudder
3. 4 screws
4. thin wire for the pushrods.