Using 1S lipo cell with or without voltage booster for DLG or similar application with Minima receivers, UPDATE 1

UPDATE 1, 4 March 2014

My Tiansheng Wing/Carnard works without voltage booster.

When the single cell voltage booster I bought from Hobbyking broke a wire, I plug the battery directly into the Minima in my Mini DLG, and it works.

I won't be using voltage booster anytime soon.

 

31 January 2014

I found on 29 January 2014 that a Minima works on 1 cell lipo without voltage booster, and so does the servos. Maybe I will have problems while in the air, only experiment and experience will tell.

I have 3 numbers of 350mAh 1S lipo which were for a Walkera helicopter.
I trim the connector by cutting off the lug/tab nearest the black wire and it can be plugged directly into a Minima.
A Minima receiver has 6 channels.
All the channels share the same + and -.
Battery plugged into a channel (not necessary Channel 6) will provide power to the receiver and the servos.
I then plugged in 2 Kingmax 3.2g servos and it works ok indoors.
I shall do a range check in the field.

If noseweight is required or if 350mAh is insufficient, I can double the battery capacity by plugging another lipo to another unused channel.
This will give me 700mAh with increased weight in the nose (or elsewhere).

This would not be possible if I use a voltage booster.
If the range and servos work for the model, I will not use voltage booster.
If there is a problem in the air or the range is not enough, then I will add a voltage booster to bring the voltage to 5V.
If the battery's capacity and/or voltage is insufficient, then I could use a larger 1S lipo and/or a voltage booster.
If multiple lipos are used, then they have to be of the same voltage, with or without voltage boosters. I think capacity can vary but I would think that preferably they are identical in all aspects, to have the same voltage throughout otherwise discharging among cells can occur.

Did some surfing on 31 Jan and found a thread on 1s without booster.
It has been done for years.

Boeing Bird of Prey

Spencer said he modelled the Boeing BOP and it was a failure. There was insufficient yaw stability. He wanted to try again and asked us to join in. Each produces his version and lets see whose gets to fly.

 

First off, it looks ugly. This is how I might do it.

Fuselage

This component will provide lift and house all RC gear and a Turnigy 1811 motor will be mounted as a pusher, driving a GWS 5"x3" tractor prop.
This will be constructed of a rectangular piece of blue foam: 28" x 5" x1" thick. Hot wire cut the section. Sand to shape, cut the slots, pockets or grooves.
Motor is mounted on 2mm ply, secured with nylon tie (don't intend to do any thrust adjustment), epoxied to a slot in the rear of the fuselage.
The battery, receiver, esc are mounted as far forward as possible and side by side if the wires are long enough.

Wing

A rectangular wing, acting more as a stabiliser, to be shaped and cut from 3mm balsa sheet or 5mm compressed foam (which then has to be suitably stiffened). Length of 30", chord of 3". Hinge the elevons, make score lines for the wing tips and fix that to 90 degrees. Cut out a V-piece from the inboard section and join the two wings into a swept back wing with dihedral.
Connect up to the 2 elevon servos in the fuselage, use wire in plastic tube.

Choosing a power system

I like this from Himax:

Choosing a power system:

Power system can be chosen based on the type of flying expected of the model and all up weight of the aircraft. Sedate flying from a hand launch requires 35 watts per pound (W/Lb). Taking off the ground needs approximately 50 W/Lb. Aerobatics and good climb performance, 75W/Lb. Anything more than 75W/Lb will result in excellent performance. Based on the weight of the model and the flying desired, the power required can be calculated. Select the voltage of the battery being used. It is best to use a loaded voltage of about 90% nominal. Now, calculate the current required. From the chart, pick a motor at the voltage you intend to use and find the prop that pull the required current.

Except, none of the motors I have, comes with its chart or the information about A and propeller size, and I don't have a wattmeter to test out the current draw on the propellers I use.

28/1/2014: Well, got to start somewhere, so I placed order for a Hobbyking's X1 Wattmeter

This from Hobbyking's website, much higher W/Lb is recommended:

A basic guide to Electric Flight

An under-powered model is a disaster waiting to happen, here is a rough guide to choosing the electric power train needed for various model types, bear in mind that over-powering is fine but the penalty is additional weight, and a good model is one that is balanced in terms of power, flying weight and build quality. This guide is as the title says, a ROUGH guide and offers a basis from which to choose a power train for your model, it is not intended to be a definative guide but will help to get you into the air with performance that will make your introduction to electric flight enjoyable and reliable.

 

MOTOR POWER CHOICE(base on reccomended AUW, or Flying Weight of model choice):

Vintage types and many non-aerobatic indoor flyers -

50w~70w per 1lb

Trainers, gliders and high wing scale -

70w~100w per 1lb

Sport flyer with general aerobatic performance -

100w per 1lb

Warbirds -

120w~150w per 1lb

Multi engined models -

100w per 1lb (thrust from Multiple props gives in effect, more than 100w per 1lb performance)

EDF Jets -

150w~200w per 1lb

3D, F3A and high performance Models -

150w~200w per 1lb

 

LIPOLY VOLTAGE CHOICE

Based on the above, we now need to work out what voltage we are going to need to use, generally, to keep Lipo's in good order, try and keep max amps to around 50~60% of the capacity/C rating of the Lipoly Pack, for example, if you purchase a 2200mAh 20c pack, then it is rated for 44A constant discharge, so keep the max amps at around 20A~25A IF possible, it isn't always! Choose the capacity of pack based on reccomendation for the model by model manufacturer and in conjunction with the size/weight data published with all our advertised Lipoly packs, for low powered models, choose 20c packs, for general flying choose 20c~25c packs, for high performance models 30c + packs;

 

Up to 50w:

1s~2s

up to 100w:

2s~3s

100w Up to 500w

: 3s (This is the practical upper limit for 3s Lipo's, so basically, models of 5lb AUW)

500w up to 800w:

4s (This is the 0.40~0.46 glow equivalent range favoured by many club flyers)

800w up to 1000w: 5s

• 900w up to 1500w: 6s (this is the 0.60~0.90 ic equivalent range)

8s~10s packs are for very large and generally specialised models.

 

 

MOTOR CHOICE - KV or RPM per volt

Which actually means, what prop size! If you are used to IC, the simple analogy is to treat low kv motors as 4 stroke engine equivalents and mid-high kv motors as 2 stroke engine equivalents, if you are not used to IC then we can give you some examples of the approach to take, this is an important choice as you can literally choose how your model flies, however, their are practical considerations, the most obvious is ground clearance. Please refer to motors such as the NTM range, which give you prop data as well as power, dimension and weight data.

Example 1:

Trainer/Sport Model, 1lb AUW, we want 100w motor (3s 20c Lipoly) mid kv for general flying, probably around 1200kv~1400kv, so around 8" prop

Example2:

3D/F3A Model, 1lb AUW, we want 150w motor (3s 20c~30c Lipoly) low kv, 1000kv or under, spinning 10~11" prop, highly efficient at low throttle openings giving lot's of prop wash over control surfaces at all times, high thrust for low rpm and low amps draw at higher throttle openings.

Example 3:

Warbird/scale Model, 1lb AUW 120w motor, kv choice, either of the above, it is personal choice

Example 4:

High Speed Delta type model, 1lb AUW, 200w motor (3s 25c~30c Lipoly) 2200kv~3200kv motor, 5"~6" Prop, high speed/low torque, low thrust at low throttle openings, high speed from high rpm at full throttle.

 

 

FINALLY, ESC CHOICE

You have decided on your motor, so look at the MAX AMPS figure given by the motor manufacturer in the data section and generally add 25% headroom, so, if a motor is rated to 15A, then choose at least an 18A ESC, better still a 20A and so on. Next make sure that the ESC voltage is compatible, in other words, if you are using a 4s Lipo, that the ESC is rated for 4s voltage. Next, check if it has functions you desire, if you are flying a glider for instance, you will want a brake facillity so that the prop stops when soaring un-powered, allowing the prop to fold by not windmilling, we strongly advise purchasing a programme card to make programming the ESC easier. Also look at BEC rating, the BEC supplies radio reciever power for servo's without the need for a seperate reciever battery, however, the can be limited in the number of servo's they are capable of powering, if the servo count is over 4, as it is on many models these days, then consider purchasing an ESC with a high AMP rated SBEC, or a seperate UBEC, OPTO type ESC's (they have no BEC, keeping the ESC seperate from RX suply) are reccomended for large models that require a seperate reciever power supply, they are also safer in high powered, large models as they will not arm until the RX is switched on.

 

This document is a work-in-progress. Check back regularly as we expand this document.

TURNIGY® Batteries explained

Zippy: Great value for money. Average Cycle Life* (100+) and minimal voltage sag under load.

TURNIGY Standard: Excellent value, Longer Cycle life* (160+) and very low voltage sag under load.

TUNIGY nano-tech: Unbeatable performance, Longest Cycle Life* (250+) and almost 0 voltage sag under load.

*Cycle Life results from discharging at full C rate to 3v. End of life when battery has 80% capacity.

        

And also from HobbyKing's website:

Lithium Polymer (LiPo) Basics
It can sometimes be difficult to know which battery is best for your application.
For R/C aircraft there is a huge variety of batteries available and while many may suit your application your ultimate goal is to purchase a battery pack that will;
-be within your budget
-have a long cycle life
-have the correct size and weight
-give you the longest flight times
-be able to deliver the correct voltage/amp (Power)
We hope this simple guide helps you understand the different types of LiPoly (Lithium Polymer) batteries and which is right for your model.

You may have noticed by now that batteries have different ratings, sizes, plugs, wire, charge rates and chemical makeup. Lets decipher;

Capacity (mAh).
This is usually the biggest number shown on the pack and is measured in mAh (Milliamp/hour) or Ah (Amp/hour). The capacity is the first indicator of the batteries size. To keep things simple, think of capacity (mAh) as the amount of fuel in your cars gas tank. A higher capacity tank will run your car for longer. A 4,000mAh battery will run for twice as long as a 2,000mAh battery.
A 2,000mah battery will (in theory) run for 1hr if drained at a constant 2,000 Milliamps.

Discharge (C)
Discharge is the amount of power the battery can 'push' out and the number shown '20C' is an multiplication of the capacity. For example; A 20C battery can discharge at 20 x 2,000mAh which is 40,000mAh or 40Amps.
This is an important number if you know your motor requires a certain power level.
In addition to this, batteries have a 'Burst' rate, which is the amount of power the battery can discharge for a short period, usually 10-20 seconds. A typical battery label may show 20-30C, this would mean a 1,000mAh battery can discharge 20,000mAh constantly or give a sudden and short 10-20 second 30,000mAh (30A) burst of power.
Tip: A higher 'C' rated battery will last longer if run at a lower 'C' rate. Example: a 30C battery run at 20C maximum will have a longer cycle life than a 20C run at 20C each flight.

Voltage (S)
All lithium Polymer cells in any industry have a nominal voltage of 3.7v per cell. When fully charged a LiPoly cell should be 4.2v and when discharged it should never be below 3v.
You will notice that LiPoly RC packs are made up of layers of multiple cells. If the battery's rating is 3S this means it is 3 x 3.7v which is 11.1v. It has 3 layers of 3.7v each. In other words, its a '3 cell pack'.

Weight/Size
For a battery to be right for your model it must fit within the models battery compartment and also balance the plane correctly.
It's temping to choose the biggest and most powerful battery your model can handle, but this will sacrafice flight performance and if your packs voltage is too high; destroy the ESC or Motor.
Check with your ESC and Motor specification to ensure you have the right voltage pack then check the models CG (Center of Gravity) to decide on the right battery weight.


LiPoly Charging
Always use a lithium Polymer battery charger and never charge the battery above 4.2v per cell. (example: 2S, never above 8.4v)
Never leave a charging battery unattended.
Never allow the battery's voltage to fall below 3.2v per cell. (example: 3S, never below 9.6v)

This document is a work-in-progress. Check back regularly as we expand this document to include battery chemistry, dig deeper into battery technology, battery sales tricks and production methods.

TURNIGY® Batteries explained
Zippy: Great value for money. Average Cycle Life* (100+) and minimal voltage sag under load.
TURNIGY Standard: Excellent value, Longer Cycle life* (160+) and very low voltage sag under load.
TUNIGY nano-tech: Unbeatable performance, Longest Cycle Life* (250+) and almost 0 voltage sag under load.
TUNIGY nano-tech A-SPEC: Competition level cells, strongest voltage hold in the industry.
*Cycle Life results from discharging at full C rate to 3.3v. End of life when battery has 80% capacity.

     

Thrust lines on Pushers

When the propeller's rpm is increased, the thrust is increased and the model will increase its air speed until the increased drag (that is the result of increased air speed) is in equilibrium with the available thrust.

All my models pitch up when air speed is increased (except my 3D model type, whose pitching tendancy are at the least). Downthrust is used to help reduce this pitching tendancy by keeping the nose down, thus when thrust is increased, so is the down thrust component.

The other observation is, when the propellor's rpm is increased, the model rolls to the opposite direction of the propellor's. I understand this to be the same as torque-rolling. It is especially evident when performing rolling from hover. I normally use tractor propellors, turning counter-clockwise. It is easier to allow the model to roll left by releasing both right aileron and rudder which were held when in an hover.

There is a difference though. My 3D planes have hardly any downthrust or right thrust, whereas my ordinary model has varying degrees of downthrust and right thrust. Especially obvious is the Red Triplane that was given to me. It has  ridiculous amount of down and side thrusts.

Even though it works, I don't understand how pointing the thrustline to the right help to balance torque roll. How could doing that create a rolling moment in the other direction?

Without understanding fully, I still like to consider the application on pusher models. If I have the propellor as a pusher, should I introduce thrust line deviations?

There are two possible deviations to the thrust line, whether it points upwards or downwards, and whether it points left or right. To understand the turning moment created by these deviations, the first thing I need to understand is, where is the pivoting point?

Is the pivoting point at:

• the centre of gravity; or
• the centre of drag; or
• the centre of area; or
• a combination of the above?

WBP-1 Flying Plank; modifying Tian Sheng's TS800; RC WBP-1

Introduction

I wanted to build and fly a WBP-1 after I built a 'Red Butterfly'. I tried to chop up Tian Sheng's TS800 but that wasn't successful, the CG, while always there, was difficult to catch. Under the 'History' is, well, history, under 'RC WBP-1', the flyable WBP-1 using lightweight gear.

RC WBP-1

History

I have flown the Red Butterfly. I gave it to Wong and he told me the reason he is not flying it now is because he has to replace his motor.

The Red Butterfly is a 4 channel flying wing. I could do a light and small scale model of some real planes.


A few inspirations from the internet.
The first 3 photos shown here is of the Al Backstrom's WBP-1. A profile rubber scale was offered in Aeromodeller.

Flying wing is long in the tooth.

It can also be sleek looking.

Perhaps I could do a quick-to-built the original white WBP-1, also called the flying plank. RET control, 5mm foam with 2mm carbon rod leading edge glued and taped on, Guardian surgical tape hinge, 1" blue foam pod either with integral canopy or seperate moulded canopy, fixed fins, Turnigy 6A motor and ESC, GWS 5"x3" propellor, 2S 500mah battery, 2 Kingmax 3gm servos embedded in the wing just behind the leading edge for the elevons. Span not exceeding 25" (original is 25'). Below the plans offered in Aeromodeller.

 

Step by Step Construction

1. Begin with the wing. Mark out the wing's outline (25"x5" or 20"x4"), the elevon's hingeline (we will use spanwise strip elevon, not the partial outboard elevons) and the centre line of the wing onto 5mm foam board. This will be the lower surface of the wing.
2. Cut out the single piece wing. The cuts to be perpendicular, at 90 degrees to the board.
3. Glue the 10mm x 0.5mm carbon fibre strip to the top of the underside of the wing. Leave approximately 2mm of the strip exposed from the foam's leading edge. This 2mm ledge is to accept the 3mm carbon fibre rod.
4. Glue the 3mm diameter carbon fibre rod against the foam's leading and carbon fibre strip.
5. Shape the top surface of the foam's leading edge. One way is to sand lightly, another is to depress the foam with a hard and flat object.
6. Big gaps between the foam and rod or the rod and strip may be filleted in. Leave minor gaps alone as it will be taped over.
7. Place the wing assembly upside down to mark out the two servos location. All servos I used has the servo lead at the end where the rotary drive is located. The rotary drive is where the torque will be, so place it close to the leading edge, but no parts of the servo should clash with the carbon fibre strip. I don't cut my servos' mounting lugs, place the servo flat on the wing, rotary drive to the leading edge and facing outboard, mark around the servo including the lug position.
8. Cut out two holes for the servos. Slitting is sufficient to accomodate the servos' mounting lugs. The cuts to be perpendicular, at 90 degrees to the board. Dry fit the servos, do not glue in at this stage.
9. Place the wing upside down on the cutting mat. Orientate the wing vertically so that your master hand can draw the cutting knife towards yourself. I am a right hander, so I position the wing's trailing edge towards the left and the leading edge towards the right and I place my 12" ruler on the elevons.
10. Seperate the elevon strip from the rest of the wing with the cutting blade at approximately 45 degrees, blade resting against the bottom edge of the ruler which is right on the hingeline.
11. Flip over the elevon strip so the two 45 degrees edge cut meets with a 90 degrees  at a continuous point. The resulting V-cut is at the bottom of the wing.
12. Lift up both pieces, flip the elevon strip and place it against the upper surface of the wing so that the 45 degrees edges meet to form a 90 degrees ridge.
13. Apply Guardian's 1" surgical tape over this ridge. This is the underside of the continuous hinge.
14. Cut a rectangular piece of self-adhesive vinyl sticker. The vinyl should be larger than the rectangular wing with hinged elevon strip by about 1".
15. Apply sticker over the top surface of the hinged wing, wrapping around the leading edge.
16. Make the radius corner, cutting the sticker and foam. Trim the sticker.
17. Temporary cover the servos' opening on the underside of the wing to prevent dust and debris from sticking to the exposed sticky side of the vinyl sticker. The wing is placed aside and attention is now directed to the fuselage.
18. The fuselage shall comprise of two parts, an upper part and a lower part. Trace the complete fuselage shape onto 1" blue foam. Mark out also the wing's position and thickness. With a ruler placed on the lower line of the wing, extend the line to the nose of the fuselage. This line indicates the separation between the two parts of the fuselage. The separation line and wing slot lines are transferred over to the other side of the fuselage. There is no need to transfer the fuselage outline.
19. Cut along the fuselage outline.
20. Round the corners, including the canopy, the nose, and the turtledeck. The separation line and the wing's position and thickness should still be visible on both sides.
21. Cut out the wing slot. As the foam is 1" thick, and some accuracy is required, this is not as easy as cutting the 5mm foam. If I have mechanical means, such as a jig saw, I would use it now. Since I don't, I shall use a 6mm drill bit and drill the blue foam with my Ikea screwdriver/drill. Then using a NT cutter with a sawing motion, cut out the slot. The sighting advantage for having both sides having the same lines drawn is now realised. Leave the fuselage to one side and focus on making the motor assembly.
22.  On a piece of 2mm ply, mark out the outline, vertical centre line (not allowing any side thrust), points of the mounting holes, and the centre point of the firewall. The mounting holes shall be positioned in a 't' manner, and the motor wires will pass on either side of the lower part of the 't'.
23. Using a pair of shear, cut out the firewall.
24. Bond this firewall to a piece of 8-10 mm rubber foam. The markings should not be obscured. Trim the rubber foam to the outline shape of the firewall.
25. Drill the ply and rubber foam firewall. Use 3mm drill bit for the mounting holes, 6mm for the motor shaft clearance centre hole. The slot for the motor wires will be dealt with later.
26. Install four 2.5mm blind nuts on the ply side of the firewall.
27. Install the motor mount with four 2.5mm x 12mm long hexagonal bolts. Thread the motor wires and secure the motor on the motor mount with the set screws. Install the prop-saver on the motor shaft and band on the propellor. The motor mount is against the side of the firewall that has the rubber foam.
28. Take out the wing and the fuselage and mark where the firewall will be bonded to. I don't know how much of thrustline deviation to allow for, so it is set initially as zero-zero and flight testing will dictate how much is needed. A line for the firewall position is marked on the top surface of the wing. This is the line along the ply face. The set back required is when there is 10mm clearance measured between the propellor tips and the trailing edge. This clearance is for the compressibility of the rubber foam, the side thrust if necessary, and the forward flexing of the GWS 5"x3" propellor.
29. Slot the fuselage over the wing, if the fuselage is not flush with the trailing edge, lengthen the wing slot by sanding away the portion where the leading edge of the wing meets with the fuselage.
30. Transfer the firewall position line to the fuselage. Remove wing, keep it aside and extend the two ends of the line over and around the top of the fuselage.
31. Cut the fuselage along the transferred line and then the separation line. I now have a top half and a bottom half.
32.  Glue the firewall to the top half of the fuselage, the ply side towards the blue foam and the rubber foam faced motor side towards the rear. Remove motor, but leave the motor mount on and sand the junction of the firewall and top half to remove big bumps.
33. The motor mount is arranged with a pair of its arms vertically and the other, horizontally. There are two diagonally set-screws to hold the motor in placed, If the lower set-screw is on the left, the three motor wires will pass on the right, and vice-versa.
34. Plan and mark out, on the bottom of the fuselage top: the motor wires' route, the pocket to the ESC (whether horizontal, vertical, on edge or any angle in between), the routing to connect to the receiver and the battery. The motor wiring uses 2mm bullet connectors, make it so that the ESC, with its bullet connectors and the plug to the receiver, can be removed. If it is possible to have the receiver located in the fuselage top, so much better. Decision will be based on: having the ESC (and Receiver if possible) as far forward as possible; a neat and direct routing of wiring(even if the wires have to be doubled/tripled back on itself and be located in a pocket or a slot); ESC and receiver to be removable from tight fitting pocket/s or slot/s. It maybe possible that individual pockets can become a larger slot in the fuselage top; so long as it can be covered with vinyl sticker and is not too much out of shape, it is fine. There is not going to be much issue with weakening the fuselage top, leave at least 1/2" length of foam at the rear to provide buttress to the motor and it should be fine. Remember that the servo plugs of the two elevon servos will passed through the wing if the receiver is mounted on top and if the receiver is mounted on the bottom, the ESC plug will pass through the wing. If receiver will be located on the bottom, then a pocket/slot at the bottom fuselage piece will have to be planned.
35. Plan and mark out the vertical slot for the 2S500mah battery. It is located at the nose, as far forward as possible, leaving at least 1/4" foam in the corners and avoid the location of the nose gear. Check that the battery plug of the ESC is long enough; if the plug can be pulled through the slot and has sufficient length to be finger gripped, it is enough. In operation, after plugging in the battery to the ESC, the length of wire is doubled/tripled and stuffed into the slot. If the receiver is to be located at the underside of the wing, then the pocket/slot and groove for the receiver and its wires has to be marked out. 
36. Cut/saw/hollow the fuselage's various pockets, slots and openings. Trial fit of all components, temporary plug in two elevon servos and check that it functions properly. Also check that the motor rotates in correct direction.
37. If optional nose gear is desired, a wheel pocket is hollowed out from the lower fuselage half. The nose gear is built with a rectangle piece of 2mm ply, slotted to accept the wheel. The wheel is inserted into a L-bent wire and another bend locks the wheel in placed. Then the wheel assembly is glued on either to the top or bottom of the ply piece, and the nose gear glued to the fuselage. 
38. From the photographs, there is a single main wheel in the fuselage, but two main wheels are seen in the later photographs. If desired, fabricate the main gear following the steps for the nose gear. And if the twin-wheel main gear is desired, just modify the ply plate into two slots and add a pair of fairings.

Tiansheng TS800

TS800 Specification No motor required
Material: EPO Foam (Crash-resistant)
Length: 490mm
Wingspan: 600mm
Take-off Weight: 62 grams
Discard rear half the tail boom, insert central fin, install RC gear and a flying wing similar to the flying plank results.
Or cut off at trailing edge, install twin fins, motor and RC gear and a power model results.

Yesterday I toyed with the RC gear I have.
I have Kingmax 3.2g servos, Hitec Minima, and from a Walkera helicopter, a 1cell lipo mains charger and 3 numbers of 150mAh 1S lipo.
I googled if it is possible to operate the RC gear with only 1S, turns out it has been done but with larger capacity.
The lipos for the Walkera has a white connector and it cannot be plugged into the Minima.
I thought of soldering on a servo plug to the lipo, but then I noticed that the position of the sleeves is very close to that of the Minima's pins.
I don't know if the sleeves will mate with the pins.
I took one lipo, trim off the lug/tab nearest the black wire and discovered it can be plugged into the Minima.
The Minima was blinking red and green.
So I bind the Minima with my new 9X and it works!
Plugged in 2 Kingmax 3.2g servos, program the 9X and it works out ok.
The nose of the TS800 has a very small cross section, limited space to mount the receiver and battery.
I placed both lipo and Minima together to save space and make the cutting easier and minimal.
The nose of the TS800 is also very short and the 10cm servo plugs is long enough to be routed to the wing.
I need not use extension wires.
At first I thought I could glue on the canopy for strength and cut out grooves in the bottom to access the RC gear, but I think it is neater to have removable canopy.

Holding the airborne RC gear in my hand, I find it very light and compact.
If servo is 3.2g a piece, Minima is 4g, and the 150 mAh lipo is about 12g, total weight is only approximately 22.4g. I think it is perhaps the same weight of the stainless steel ball bearing nose weight that I removed from the canopy of the TS800.

So if the chopped up TS800 with new fin weighs 30g, and my hinges, horns, pushrods and tape weighs 10g, the total flying weight of the flying wing TS800 will be 62.4g, very close to the original TS800!

Some weight might be necessary to add to the model in order that the CG can fall within its allowable range, and this would be determined on the field, but the prospect is good indeed.

New Purchase from Rotor Hobby

15 February 2014

I went to buy a big bottle of kicker, 2 digital servos for the Katana's tail surfaces. Open the boxed Techone Swift kit, and ended up with a fully assembled TechOne Sbach because I was offered a good price with ESC and servos.

I flew it on Sunday, 16 February 2014.
First flight was with a 3S1300mAh 20C battery which I had used for the Katana. Only ca 3 minutes when ESC reduced the power and battery was too warm.
Second flight was with Wong's Zippy 3S1500mAh 20/25C battery. Only ca 5 minutes and battery was too warm.
Third flight was with Fred's puffed up Voltron 3S2200mAh 25C battery. Only ca 7 minutes and battery was too warm. I will have to ask him if that battery can still be used, because it was over discharged.
The model itself is capable. I will need more flights before I trim it properly. But first, I have no suitable batteries, so I can either use smaller propellers (and motor?) or buy a set (I think I will need 4 batteries) of Turnigy 3S2200mAh batteries (minimum 25C, but I think 35C or higher will be much better).

18 January 2014

Hitec Aurora 9x transmitter only
4 units Kingmax 3gm servos, listed price is 6.90 each.

Andy's DIY, my thoughts on KF

Photos from Andy below.

I think that the KF foil is somewhere in between a flat plate airfoil (any plate is an airfoil) and an airfoil.

A flat plate is thin whereas an airfoil is thicker, so a flat plate will have less drag. Improving the leading edge ought to render it less draggy, that's where KF comes in. An airfoil is airfoiled to reduce the drag that is inherently due to its thickness. It seems a KF (I haven't tried KF myself), introduces leading edge and thickness.

Thickness is good for lift capability because it introduces camber to the air, camber causes the air to flow downwards to create reactionary lift, as I termed it, and by the reduction in pressure on the upper surface which is also called lift (so by this definition, a flat plate has no lift since it is not cambered). A KF seems to be just one way of relying on the air to create a sort of boundary to guide the air flow, which in my opinion, will not be as effective as an airfoil because I would guess that despite the slow speed of our model, there wold still be turbulence in the case of a KF and turbulence is energy dissipated.

To add thickness, an airfoil could be positioned at an angle, this creates more downthrusting of the air and it modifies the effective airfoil shape.

At low to medium angles, the flat plate, with its flat leading edge, has about the same drag since turbulence at the leading edge was existing even at zero degrees of angle. When there is no difference, then the state is constant and we woudn't detect any changes.
At these angles, reactionary lift is produced. Reactionary lift increases fairly proportionally and constant with the angle since the downward vector element of the airflow increases by the same angle. Induced drag is correspondingly increased since the lift is offset to the direction of flight.
Come to an extreme angle, the reactionary lift is of no use since it is at such an angle that there is no vertical lift component.

At zero angle, the airfoil with its camber (symmetrical airfoil excluded here), has both reactionary lift as I termed it, and the more traditionally described lift element due to lesser pressure on the upper surface. No turbulence at the leading edge.
At low to medium angles, the camber changes, and the leading edge guides the air minimising the resulting drag. Reactionary lift increases fairly proportionally and constant with the angle since the downward vector element of the airflow increases by the same angle. Induced drag is correspondingly increased since the lift is offset to the direction of flight.
Come to an extreme angle, leading edge drag forms and we noticed instant changes to the model and there is no practical lift for the same reasons as the flat plate.

The sharper the leading edge, the less leading edge drag at zero to low angles, but the usable angle range is proportionally limited. With a blunt leading edge, you get a wider angle range that is usable, but you have more drag at zero angle to begin with.


Andy scratch-built this Mini-Popwing.

He and Hanif each built a mini ME109 from a plan available off the internet. I understand that Hanif arrange an internet company to do the cutting.

Hanif with his Spitfire in October. All foam board, he followed the plan and instructions off the internet. Too bad he followed the foam spar instruction because the wing was noticeably weak, a bit of G- manouvre and it became bendy.