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?

Quad controlled nano plane

4 October 2016

This is the Eachine E010, only available as Mode 2.

I like the four bladed propellers in the protector rings and the rings are duct design with a good lip for better draw.

The vertical lift seems more powerful than the CX10A (and of course  more than the WD-TX which is heavier). It could be because of different motor speed control setting but perhaps not.

If I want, I can connect the ducted fans to WLToys receiver board and make an RC jet.: Boeing, Airbus or even the A-10? Many possibilities.

 

 

18 August 2016

Not a plane but I bought another CX10A and a CX-10WD-TX.
The latter is WiFi controlled, comes with a transmitter and it is a FPV drone that can take photos and videos. It also have height hold, one touch take off and one touch landing. I bought it from Rotor, listed price 69SGD.

7 June 2016

Ooh, a Blériot 115 or 155 is also possible and it seems they are easier to do than a HP42.

The 155 had the same 4 engine configuration but there's no 'inverted gull' kink to the lower wing and the engines were mounted clearly on top of the wings.

There's one door and it was at the nose!

The 155 was smooth skin, no corrugated steel sheets.
Easy radiators to do.

Both upper and lower wings were of equal span, so I don't have to measure the spans of the model.

It had interesting names, in this one, it was called 'Clement Ader'.

 Single tail, unlike the boxed tail of the HP42.

 This was the 115.

 It seems it had a front viewing windows for the passengers.

Don't know if the access for passengers were from the nose. But pity the pilots/navigator, sitting exposed.

Which motor should connect to which arm of the quad controller and which direction should that motor turn? This is what I came up with, but there's something wrong with it.



This configuration would work, but aileron input yaws the plane and rudder input rolls the plane. I haven't stumble on the correct configuration yet.

It's not just the inputs I am concerned about, it's how the quad controller will stabilise the model. When the quad controller detects a roll, translated, the low side speeds up when I'd rather have it speed up opposing motors that give a yaw, which is a roll...see? See? I can confuse easily by writing too much, no wonder I didn't get what I wanted.








So, here's the final configuration which I think is correct.

When I want to roll to the right, quad arms 1 and 3 gives more voltage, the opposing pair of motors at 1.30 and 7.30 speeds up and the torque rolls the model right.

When I want to yaw to the right, quad arms 2 and 3 (I have to verify this) gives more voltage to the motors at 1.30 and 4.30, which speeds up and yaws the model towards the right.

When I want to pitch up, quad arms 1 and 2 gives more voltage to motors at 4.30 and 7.30 and the model pitches up.

16 May 2016

This Eachine H8 mini was delivered last week. I bought it from Banggood because it is cheaper than the Cheerson CX10A, have bigger motors, propellers and the battery connection uses the white plugs.

I bought a Mode 1 type but the aileron and rudder are on the wrong sticks. It is actually a Mode 3 transmitter.

It flies ok, quieter than the CX10A, but it took conscious effort to adapt to Mode 3. So I could hover but not much more.

The propellers are bigger than CX10A's but smaller than the Hubsans which I had bought a few for experimentation. The motors spins free but that is probably because of the increased mass of the propellers?

The plastic frame is flexible and does not break. The guard rails looks ok but are not as useful as a cage because they are too small and do not form a protection ring.

28 April 2016

I am not sure if my visualising of movements is correct.

Question:
If the motors and propellers are forward facing but the board is mounted horizontally, the throttle, ailerons and elevator direction is the same, but what is the effect on the rudder, i.e. vertical axis?

There are two things to consider: the self-stabilising horizontal rotation about the vertical axis and the stick inputs.

Arguments:
When there is a deviation, for example, the quad board were to be displaced in a clockwise rotation (in a vertical axis, i.e. turning right), the two pairs of motors placed horizontally forward facing will react to compensate by rotating about the horizontal axis in an anticlockwise rotation (the model will bank right). This is contrary to the desired banking direction as what we want is for the model to bank left for left turn.
When the rudder stick is pushed to right, we want the model to bank right but the horizontally aligned motors will cause the board/model to bank left. This is also contrary to the desired banking direction because wheat we want is for the model to bank right for right turn.

Solution:
I think I can get the desired rudder stabilising and output by swapping the two pairs of motors, for example for the front-left motor, which translates to bottom-left, it shall be changed from clockwise rotation to one which has anticlockwise rotation.
Front view:
CA     to    AC
AC     to    CA

5 April 2016

Last night I decided to open up the CX10A. I didn't want to but I had to. It's either out with the soldering gun or out with the CX10A; there's no point keeping toys you can't play with. Forego the idea that one day it can be salvaged as parts for a new toy, life is too short.

First I pinched the 4 propellers out of the motor shafts. Then I took out the 4 screws and carefully plied open the latches which are molded to the white plastic bottom cover piece. Gingerly the top cover was removed and the PCB pried out.

Can't see really, but with the camera phone to the rescue, all becomes clear where the wire was disconnected. I tried to see if the solder will met the plastic sleeve, so I don't have to strip the wire: nope. I tried to strip the wire with a pair scissors and cut it instead. I tried again but was really gentle this time and managed to bare a fresh wire core. I tinned the bared wire, or at least I think I did. All this time I can't see what I was doing and it was by 'feel'. Whether the wire is tinned or not I do not know. All I know is that I tried. The soldering part was completed by 'feel' too. I tugged the wire and it seems to hold. The CX10A was re-assembled and it worked.  I then discovered there's this small square transparent plastic piece. I suppose that is to be inserted between the battery and the PCB. It worked for a couple of flights until I crashed it and the same motor stopped working.

I hadn't stored away my soldering gear yet, so I disassembled the CX10A, performed the soldering again (this time I didn't bare a new length or tinned the exposed end), assembled the CX10A and it is working. This time, it was much easier, experience equals familiarity? I didn't fit the small square transparent plastic piece, I wanted to but didn't find it (later on, I stored the plastic piece in the battery compartment of the transmitter.

I think that during a crash, the contact point broke off when that motor twisted. So I thought of hotgluing the motor to the bottom cover, knowing though, that that would mean that I will have some difficulties if I have to disassemble the CX10A again. I thought of superglue, UHU and then settled on a particular glue paste that came in a tube. This glue says it is all-purpose, it looks to be some form of paste compound which won't dissolve in water when dried. I remembered that the paste dried hard.
I applied a bit of it on the exposed sides of the motors after assembly. Then I decided to installed the cage (it has snapped in a few places, but should still be ok) and applied more glue to the bottom of the motors. Only time will tell, but I think this is a good move.

My CX10A flies only a bit longer than 3 minutes and the battery was hot to touch.

1 April 2016

It is the end! Banggood does not ship their lipos to Singapore, no matter how small!

I bought another CX10A and was having a good time until one motor stopped reacting. Perhaps it is a simple matter of opening up and re-soldering, but what shall I do if it is not. Meantime I bought another mini/nano Quad: Eachine H8 Mini Headless Mode 2.4G 4CH 6 Axis RC Quadcopter RTF, for $18.50. It looks to be larger and the lipo is 150mah with the white plug.

I also bought 10x of the male and female white plugs. They would come in useful one day.

30 September 2015

I printed this drawing on A3 for study. The Cheerson propeller fits inside the prop arc and the motor fits in the nacelles too.

A wing jig is required to have the wings assembled correctly because the top and bottom wings are polyhedral and the struts are numerous and requires careful alignment.

Prepare jig and slot in long strips of PVC to form the warren-truss for both front and back struts.
The struts between the top motors and the bottom motors to be made rigid. Glue CF rods to these four struts (front and back).
Prepare and finish the wings, checking dihedral breaks with jig.
Solder magnet wires to motors and glue motors onto wings.
Assemble and glue the jigged struts onto the lower wings and then the upper wings.
Remove jig and leave the glued in struts in placed. The jig would be destroyed in the process.
Cover motor with paper nacelles.
Glue on the diagonal struts.
Tidy up the motor wires. Solder motor wires to board.
Place and glue the biplane onto the finished fuselage.
Run the motor wires to the fuselage.
Cover fuselage and wing joints with paper.
Glue the board to nose.
Make hatch to access board. To switch on and to charge.
Glue the tail and landing gear to the fuselage.



The 4 arms (and SM LEDs) would protrude pass the fuselage's outline. The propeller fits in the propeller arc described.

Overview.

Comparison with 20" Kirby Cadet.

Perhaps 15" wingspan?

 

 

 

 

 

 

 

 

 

The motor would fit nicely in the nacelle's outline and the propeller is just about the right size. There seems to be no space for detailing the Bristol Jupiter engine.

 

 

 

 

 

28 September 2015

I took the Cheerson CX10A out yesterday and couldn't get it to bind. I charged the quad and the USB charging was lighted for a very long time. I picked it up and felt that the 1s cell is very hot.

I haven't been flying the Cheerson CX10A for a few months (maybe 6 months). I think the lipo was damaged by the deep discharge. I could buy a replacement cell from Banggood and replaced the damaged battery but I don't think it is worth my effort. I didn't enjoy flying it. I suppose the board and motors are ok from the last flight many months ago, so I thought how I could re-use and modify it to airplane use.









First to mind was a 4-propellers biplane. Preferably with 2 motors at the top pair of wings and 2 at the bottom. I scour the internet and found the Handley Page HP 42.

With this arrangement of 4 motors, I could place the board in a horizontal position. So long I make this model of HP 42 to be free flight capable, there should not be any reason that I can't control the flight direction when the board and motors are working. Infact, I would have auto-stabilisation which makes flying even easier.

When the model is banked, the 2 motors on the inside pair of wings would spin faster and the opposing twins slower. When diving, the 2 motors on the lower pair of wings would spin faster and the upper pair slower. This would keep the model in a level attitude and pushing the throttle up will have the model fly faster and higher.

The model could be built from simple foam and paper and I could extend the motors' leads by using magnetic wires instead since I have ordered some from Banggood.

The CX10A weighed 12.0gm. I suppose a Handley Page HP42 under 20gm is possible since there is no other airborne electronics to add.











I opened up my CX10A and noticed I don't have the antennae like in the CX10, maybe the antennae is printed on the board. As it works, I am not bothered.

Here's the top view. The charging socket is at the top and the switch is under the board.

A study of the connections of the batteries and motors. Positive: White, Red. Negative: Black, Blue






































































I like minimal intervention and work; I don't like wasting. So I thought of how I could make full use of the switch and charging socket. While it is a simple matter to solder battery connectors and use that as a switch and charging socket, just because I like to do minimal work, I think it might equally be easy if the battery and board are in one unit, like the way it came in, and provide recess instead to have access at the built-in switch and charging socket.

The placement of the board could simply be atop the upper wings of the HP 42 for easy access or I could do some other model with the board tucked in somewhere less conspicouous and even have the small LED shining bright. And this gave me this idea. A X-Wing Fighter.

Have the motors either in tractor or pusher mode.
Have the board glued underneath the fuselage.
Have thin transparent pvc foreplanes if necessary.

Maybe the foreplanes won't be necessary because of the mems gyro onboard.

Whatever it is, the most important thing for success is that the model must be able to glide.