Frequently Asked Questions
Questions and Answers
- Where shall I start?
- I am a Beginner, what should I know?
- What does it cost?
- How fast can it go?
- How long does it fly?
- How far can it fly?
- How high can it fly?
- How much is the payload?
- Where can I get the firmware & documentation?
- Where can I buy a kit?
- Are you really sure you don't want to sell kits?
- Please, please, I really need a kit!
- What's the reason you don't want to sell kits?
- Where can I buy assembled boards?
- Can someone build me a quadcopter?
- Are there any objections to include the PCB's .brd and/or .sch files in the releases?
- What Brushless Controllers are recomended?
- What's the size of a typical NG?
- Can i build a bigger NG?
- Does a bigger Ufo fly more stable?
- Can i use more than just 4 Motors/Propellers?
- What about Oktokopters?
- What does the S-Rating on my batteries mean?
- What does the P-Rating on my batteries mean?
- My Battery has 3S1P, what does it mean?
- My Battery has 3S2P, what does it mean?
- What does the C-Rating on my batteries mean?
- What's the difference between a 3S and a 4S battery concerning the flight-time?
- Which requirements need to be fulfilled for using 4S Batteries?
- Why go for larger Props instead of 4s?
- What are the disadvantages using 4S or 12" Props
- What Battery to go for?
- Can i use the new A123 LiFePo Batteries as well?
- How long does it take to charge the batteries?
- Can i speed up the charging time?
- What Motors to go for?
- I like Inrunners, can i use them?
- What does kv mean?
- I want to build a specially designed frame, what materials to go for?
- Where can i save weight?
- Is it possible to learn flying on a simulator?
- How long does it take to put all the stuff together?
- I have a HW-0.22-mini-r2, but the accelerometer does not work! What am I doing wrong?
- Where can I find QNGCtrl for Mac OS X?
- Who is ilogbot in the chat?
- How does a PID controller work and how do I tune it?
Questions and Answers
Where shall I start?
First of all, read the documentation. Starting with the chapter Requirements you will find detailed instructions on what you need, where you get it and how to assemble it all. Check out the UserCopters page to find proven motor, propeller and BLC combinations.
I am a Beginner, what should I know?
You may want to have a look at the Quadrocopter for starters talk from FrOSCon 2010
What does it cost?
You can get started with about 500 Euros for the copter. You can find detailed prices for the single parts in the current PartList for HW-0.22. You'll need up to another 500 Euros for ground equipment (soldering iron, charger, remotecontrol) depending on what you already own.
How fast can it go?
The current confirmed speed record is about 75km/h or 45mph.
How long does it fly?
You can approximate it: Let's say the motor/controller/prop lifts about 10g/watt. A standard NG weighs about 1000g so you have around 100W on hover. A standard battery has 11.1 volts and 2200mAh, this makes 24.42 Wh, so you can fly 0.2442 hours, or about 15minutes.
A larger battery and a lighter copter will increase the flight time up to approx. 40 minutes.
How far can it fly?
Until you don't see it anymore (and probably even further). Seriously: Radio Equipment can get you about 2000-3000m range for line of sight, but you'll need to see your copter and its attitude to control it.
How high can it fly?
It will fly about 1000m high with a standard radio gear before it loses connection. You'll lose sight earlier than that, and you'll have to adhere to the local regulations.
How much is the payload?
A standard NG is capable of about 300-400grams extra weight. If you want to carry more, scale it up, use 12" props (propellers) and/or 8-12 motors and it will lift 1.5kg easily.
Where can I get the firmware & documentation?
You find firmware and documentation in the release zip file on the Download page.
Where can I buy a kit?
You want a ready to fly kit? Try your local RC model store and buy a RTF (ready to fly) model if you are looking for a kit. We do not sell nor support kits and we don't intend to change this in the future.
Are you really sure you don't want to sell kits?
Yes, we are very sure of this. Our partlists are essentially kits with order numbers and links. It's just that you have to order the parts by yourself.
Please, please, I really need a kit!
Please go back 3 questions and re-read. To make sure the you understand, I will repeat: We do not sell kits. Nor are we interested in doing so.
What's the reason you don't want to sell kits?
Because we want to keep a steep beginner entry. We are a non-commercial community project and nobody of us gets paid for doing support. So we have to keep that to a sensible level. By not selling kits we reach a different audience than otherwise.
Where can I buy assembled boards?
Normally, we do not sell assembled boards. To make life easier for software developers and similar minded folks with a background not in electronic gear, we are selling fully assembled flight control PCBs in the UAVP-NG shop.
We advise to solder your board by yourself if you would like to build a NG. It's not that difficult as it seems and you will learn a lot more, by doing it yourself. Even untrained folks will be able to solder a NG board after a little bit of training. Take an old PCI card and try desoldering and soldering some of the parts on it. Note that SMD 0805 is quite big, it can be easily soldered with a little bit of experience.
Can someone build me a quadcopter?
Now, we probably could. But I'm pretty sure you will not find someone interested in it. Nobody of us has commercial interests. Our hardware has a CC-BY-SA-NC license making sure nobody will be able to sell these boards to earn money. If you want a UAVP-NG you will have to build it yourself.
Are there any objections to include the PCB's .brd and/or .sch files in the releases?
Yes, there are many objections. We don't do Open Hardware as we do not intend to feed the chinese trolls. There simply are too many copy cats out there...
If you want to work on the PCB you will have to get known to the developers and become a NG developer to get access to our developer trunk. In this process we will do a face check and we will question your background, your objective and your goals. If we like what we hear, you can become NG developer and get access to the developer tree which contains a lot more sources and plans than what we released.
What Brushless Controllers are recomended?
What's the size of a typical NG?
Most of our NGs are about 40cm between motor-shafts. A Quadrocopter (4 motors) equipped with 10 inch propellers this amounts to a square with sides of 65cm in length.
Can i build a bigger NG?
Yes, as long as you find clockwise and counter-clockwise propellers for your motors and a large enough battery the NG is scaleable.
Does a bigger Ufo fly more stable?
Not really. As the NG uses "Fly by wire" you can make a small copter almost as stable as a big one. But this still doesn't break physical laws - a bigger copter will be heavier and a heavier copter has a bigger inertia than a smaller one.
Can i use more than just 4 Motors/Propellers?
Yes, the NG supports up to 16 Motors.
What about Oktokopters?
The NG supports Oktocopters in coax X8 and coax X8 x-formation. A flat oktocopter HAL will be built soon.
What does the S-Rating on my batteries mean?
The "nS" term specifies the number of cells in a battery in series, each cell providing about 3,7V (for LiPo's).
What does the P-Rating on my batteries mean?
The "nP" term specifies the number of cells in a battery in parallel, each cell providing about 3.7V (for LiPo's).
My Battery has 3S1P, what does it mean?
Three cells serial, one cell parallel. Often just 3S.
My Battery has 3S2P, what does it mean?
Three cells serial, two cells parallel, so 6 cells overall
What does the C-Rating on my batteries mean?
The C-Rating defines the maximum charge/discharge current related to the batteries Capacity. Example:
You have a typical battery that has 2200mAh and 20C.
At first we switch from mAh to Ah (:1000) so we have 2.2Ah and 20C.
20C is the maximum continuous discharge rate per hour.
-> 2.2Ah * 20*1/h -> 44A
This means you can pull 44 amps out of the battery without causing the voltage to drop.
What's the difference between a 3S and a 4S battery concerning the flight-time?
First, the "nS" term specifies the number of cells in a battery in series, each cell providing about 3,7V (for LiPo's).
A 4S battery has a better efficiency than a 3S battery in regards to the bl-controller/motor combination. If you compare a 3S with a 4S controller/motor combination using the same amount of power, the 4S will use less current and more voltage since they are related by P = U * I.
The electric loss is bigger with higher currents. That's related to the ohmic resistance of the motors. Its loss grows quadratically with the current P = I² * R.
The losses in the bl-controller are of lower significance. Further losses on the cables (the ohmic resistance in cable and battery) drop as well with higher voltage.
Furthermore, the bl-controller is able to convert more power if it is operated at higher voltages.
Hence, with more voltage and thus less current you have a better efficiency due to less loss of power.
Holger's BL-Ctrl is able to handle 20A peak and 10A continuous.
At 3S this results in 222W peak and 111W continuous per motor. At 4S this results in 296W peak and 148W continuous per motor.
The propeller size is relevant as well. A motor with a smaller prop needs to turn faster and therefore needs a higher voltage.
A Roxxy 2824/27 can be operated with:
- 3S battery and 12" props - 4S battery and 10" props
In that case the 4S combination is more efficient.
Which requirements need to be fulfilled for using 4S Batteries?
You will need slower motors, around 750-800kv on a standard UFO, otherwise the speed of the motors will be too high and they will draw a lot of current.
The voltage regulators on the electronics need to reduce more voltage so they'll eventually get hot (use heatsinks if necessary).
The voltage divider (regulator) needs to be set up for 4S, and your battery warning level has to be adjusted, too.
Why go for larger Props instead of 4s?
Larger, slower turning propellers have more efficiency than fast small props. The EPP 1245 are mechanically more stable as well.
What are the disadvantages using 4S or 12" Props
A 4S battery is usually more expensive than a 3S.
12" Props have more mass. You will need more torque for a quick response.
12" Props have more surface. This requires tuning the parameters to gain stability in windy conditions.
What Battery to go for?
- small, light copter: 3s 1000-1500mAh, 4s 800-1200mAh
- medium, standard copter: 3s 2200-2600mAh, 4s 1500-1800mAh
- large, heavy copter: 3s 3300-5000mAh, 4s 2500-3000mAh
Can i use the new A123 LiFePo Batteries as well?
Yes, use the 2300mAh in a 4s config
How long does it take to charge the batteries?
Lipos take about one hour, LiFePos about 15 minutes.
Can i speed up the charging time?
Yes, if you have a strong enough charger, and a "fast charge" battery
Some Lipos are specified with a higher charging rate, e.g. the Vislero 4s 2200mAh is rated "4C charge" on its label. This means you can charge them four times as fast.
Example: 2200mAh battery, 4C charging capability. This allows a charging current of 8.8A, resulting in a charging time of 15min, provided the charger can handle it (if not, it'll just charge with less Amps at a slower rate).
A standard (1C) Lipo may be charged faster as well but it is not recommended as it may damage the Battery Pack.
Most of the QC-Pilots charge their Lipo-Batteries with 1C charging current
Example: 4000mAh battery, 1C charging rate. This results in a charging current of 4A and a charging time of 60min.
What Motors to go for?
Rule of thumb:
3s LiPo Battery:
8" Prop -> ~1200-1400kv, ~25-30g
10" Prop -> ~1000-1200kv, ~45-55g
12" Prop -> ~800-1000kv, ~65-75g
4s LiPo Battery:
8" Prop -> ~1000-1200kv
10" Prop -> ~800-1000kv
12" Prop -> ~750-900kv
I like Inrunners, can i use them?
Inrunners don't produce as much torque as the outrunners do. For a quick response we need as much torque as possible.
We also need very low-kv motors, I've never seen an Inrunner with about 1000kv on 50g. If you find one that can do this let us know!
What does kv mean?
kv stands for a constant with the unit Rpm/V, a 1000kv motor will turn 10000rpm on 10V when there is no load on it (i.e. no propeller attached).
I want to build a specially designed frame, what materials to go for?
Anything light and stable: Titanium, Magnesium, Aluminum, Carbon, Fibreglass, Wood, Honeycomp, Foam
Where can i save weight?
Screws! A Polyamid screw weighs only one seventh of a steel screw
Cables! Short/Smart cabeling will decrease your weight dramatically
Coptersize! Shrinking the space between the motors will save some weight
Centerplates! Centerplates milled out of light carbon will give up to 20g extra
Is it possible to learn flying on a simulator?
Well, a simulator will never be as good as the real thing but you can do a little reflex training on a simulator. If you don't own a transmitter yet you can use a Dual Analog Pad, such as a Playstation 2 / 3 controller. HeliX is a good sim for first hops. Here is another one.
How long does it take to put all the stuff together?
If you have everything together the assembly can be done in about two weekends
I have a HW-0.22-mini-r2, but the accelerometer does not work! What am I doing wrong?
Nothing. The Circuit-board of HW-0.22-mini-r2 (and only r2!) has a bug regarding the accelerometer which keeps it from working (instad of pin 3 (SDO), pin 15 is connected (reserved)). Usually this is not fixable, so everybody who got a HW-0.22-mini-r2 PCB gets a new HW-0.22-mini-r3 PCB which includes the fix for free. You should already have gotten an email about this, if you are one of those who bought a HW-0.22-mini-r2.
Where can I find QNGCtrl for Mac OS X?
Who is ilogbot in the chat?
Ilogbot is an NG-UAVP chatbot that is able to send messages to members who are currently offline.
Type in "ilogbot later tell >nickname< >message<" and ilogbot will tell >message< to >nickname< when he reenters the chat.
Ilogbot also knows the FAQ page,
Type in "!faq 1" for the first FAQ, "!faq 2" for the second FAQ and so on.
Type in "ilogbot thanks" if he helped you out
How does a PID controller work and how do I tune it?
Check out our HOWTO page on PID controllers.