Quad/Hexa-Copter using Propeller, Gyros, Accelerometers, Compass, Pressure & GP

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Comments

  • Roy ElthamRoy Eltham Posts: 2,156
    edited March 2010 Vote Up0Vote Down
    Cluso99,
    Based on Jason Dorie's scematic, I used 10k resisters on the signal lines from the receiver to the prop pins, and 4.7k resisters on the signal lines from the prop to the ESCs. It's been working just fine for me...

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    Check out the Propeller Wiki·and contribute if you can.
  • Cluso99Cluso99 Posts: 13,024
    edited March 2010 Vote Up0Vote Down
    Excellent thanks Roy. That makes the pcb easy.

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    Links to other interesting threads:

    · Home of the MultiBladeProps: TriBlade,·RamBlade,·SixBlade, website
    · Single Board Computer:·3 Propeller ICs·and a·TriBladeProp board (ZiCog Z80 Emulator)
    · Prop Tools under Development or Completed (Index)
    · Emulators: CPUs Z80 etc; Micros Altair etc;· Terminals·VT100 etc; (Index) ZiCog (Z80) , MoCog (6809)·
    · Prop OS: SphinxOS·, PropDos , PropCmd··· Search the Propeller forums·(uses advanced Google search)
    My cruising website is: ·www.bluemagic.biz·· MultiBlade Props: www.cluso.bluemagic.biz
    My Prop boards: P8XBlade2, RamBlade, CpuBlade, TriBlade
    Prop OS (also see Sphinx, PropDos, PropCmd, Spinix)
    Website: www.clusos.com
    Prop Tools (Index) , Emulators (Index) , ZiCog (Z80)
  • SzabiSzabi Posts: 58
    edited March 2010 Vote Up0Vote Down
    Well, a PIC form Microchip you can get easily under 5$ (at least in my country) But 2$ +/- does not really matter. Using a PIC micro is worth the price because beside the ADC feature it can be used (as Cluso says) as an USB to serial interface for programming the Propeller (eliminating the need of a propplug).... For programming a PIC you don’t need anything extra. You can program serially via ICSP (2 tranzistors and a few passive components)
    My only concern is that it’s a smart device in plus and·that' an extra source of problems. (can hang, can freeze… J· )
  • SzabiSzabi Posts: 58
    edited March 2010 Vote Up0Vote Down
    Let's hope the best Cluso, I will be happy if we will not need to modify the PCB later on.
    I just googled for a ICSP programmer (is something very similar to my) that you could just add it to the layout it will make things easier for anyone who does not have a programmer.
    ·
    Are you planning to publish the PCB layout? I’m just asking because probably it would be faster to reproduce it locally (here in Europe) rather then order it from Australia tongue.gif
  • Dr_AculaDr_Acula Posts: 5,482
    edited March 2010 Vote Up0Vote Down
    My big counterrotating helicopter arrived yesterday. This has stability from the flybar (offset at about 30 degrees, standard design on a lot of helis). Also has a heading gyro. As with previous ones I've bought the big problem with these is the very slow forward speed, so I pulled it apart and moved the LiPo batteries 6cm further forward. This does not change the weight (apart from a tiny aluminium pole weighing half a gram) but it shifts the centre of gravity so increasing the forward speed. With the tail rotor on full backwards the forward speed is zero and the default setting is half speed and full speed forward can counter a wind up to about jogging pace. Now I can fly outside.

    I did a quick lift test and it can lift one of Cluso's matchbox CP/M boards.

    Thinking about how I fly this, eg the steps to fly a mission where you take off, go somewhere then return, I have been wondering what it would take to make it autonomous. Height, GPS and compass at the least, but no gyros needed as they are already present. I guess a generic board that has lots of analog I/O, and also digital I/O with the ability to measure a standard servo pulse width stream and change it a little.

    I've had this site bookmarked for a while autopilot.sourceforge.net/faq.html - there is quite a bit of useful information there. The propeller ought to have enough smarts to do this too!

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    www.smarthome.viviti.com/propeller
    Answers: 1) A quadcopter. 2) Very high. 3) The internet. 4) A lot. 5) No.
  • Cluso99Cluso99 Posts: 13,024
    edited March 2010 Vote Up0Vote Down
    After reading a lot on the DIYDrones website I have to make a comment on what I am after...

    At least initially, I am not after total autonomous flight. My aim is to aid flight for the beginner (i.e. me). When all controls are released I want the Quad or Hexacopter to hover reasonably well so as to give time for the flyer to rethink what he/she is doing. I want the prop to also add stability and to reduce large swings in the controls. We should be able to turn this all on/off via an extra RC channel. Somehow, I do not think we will need all the complexity of the DIYdrone software, but IMHO the prop will handle this with ease. We do not have to handle interrupts and we have 8 seperate processors.

    What all this means is that when we start the xcopter it will hover on the ground and we can just increase the speed to lift up. When we release the speed it should hover about the same height. A small drift would be acceptable. When we use the pitch & roll (I am mode 2, so all on the right stick - note mode 1 is more common in Australia) the xcopter will increase power to a pair of motors and reduce power to the other pair (pair=front & rear, left & right). By adding speed we can move faster in a direction which will also add height.

    I would like to keep the software as simple as possible. I am unsure if this is possible, but given the prop and it's 8 processors, we can at least make modules to do certain things. For instance, we can do the interface to get the input data in #cog(s) and output the data in another cog. Once done this should remain stable and be a module(s). This way, we can concentrate on just the computing module(s) without worry about the other cog(s). We will just get the data from a hub window, and put the data into a hub window. No interrupts to worry about. I would expect we will use helper cog(s) to do some maths functions.

    Availability of schematics, pcbs, etc...

    I will publish the schematics. I will not be publishing the pcb design. Shipping to anywhere has proved successful by unregistered airmail and takes 7-14 days and costs US$5. This way, I get to amortise the pcb setup costs and shipping (to me) into more pcbs. I will make bare pcbs and partially assembled pcbs available, and maybe some parts - I don't intend to carry any stock of the sensors (otherwise I have to factor this in) so there will be a one-off order. Also, I have a design for the prop (RamBlade) where I currently overclock to 104MHz successfully and expect to raise that to 108MHz shortly as soon as I test fully. Hope this answers some questions.

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    Links to other interesting threads:

    · Home of the MultiBladeProps: TriBlade,·RamBlade,·SixBlade, website
    · Single Board Computer:·3 Propeller ICs·and a·TriBladeProp board (ZiCog Z80 Emulator)
    · Prop Tools under Development or Completed (Index)
    · Emulators: CPUs Z80 etc; Micros Altair etc;· Terminals·VT100 etc; (Index) ZiCog (Z80) , MoCog (6809)·
    · Prop OS: SphinxOS·, PropDos , PropCmd··· Search the Propeller forums·(uses advanced Google search)
    My cruising website is: ·www.bluemagic.biz·· MultiBlade Props: www.cluso.bluemagic.biz

    Post Edited (Cluso99) : 3/24/2010 3:10:03 AM GMT
    My Prop boards: P8XBlade2, RamBlade, CpuBlade, TriBlade
    Prop OS (also see Sphinx, PropDos, PropCmd, Spinix)
    Website: www.clusos.com
    Prop Tools (Index) , Emulators (Index) , ZiCog (Z80)
  • SzabiSzabi Posts: 58
    edited March 2010 Vote Up0Vote Down
    That sounds OK with the PCB`s Cluso!

    sorry I forgot the ICSP schematic in my previous post.
    http://www.embed4u.com/wp-content/uploads/2009/11/pic-programmer-circuit.bmp
    smile.gif
  • Robert TRobert T Posts: 71
    edited March 2010 Vote Up0Vote Down
    Found a web site with a Quadracopter board based on Propeller.

    http://www.quadpowered.com/
  • A. ESERA. ESER Posts: 24
    edited March 2010 Vote Up0Vote Down
    Are you planning serial communication MCU with ADC to Propeller? If so, what will be sensor sampling rate over serial ?
    And what will be the speed of attitude estimationn loop (kalman filter etc.)
  • Cluso99Cluso99 Posts: 13,024
    edited March 2010 Vote Up0Vote Down
    RobertT: Ouch - $$$$

    A.ESER: Yes at 115,200 baud hopefully (depends on the other micro). As for the kalman filter or direct cosine xxxx or whatever, unknown at this stage. Remember, any I2C will be slower. It is only the gyro that will be on the other ADC micro.

    Remember, I am looking for a cheap solution that we all can work on using the prop as the platform. i.e. cheaper than 9DOF and use a prop.

    Since I will be making a pcb for the controller/sensors, I may as well make a pcb for mounting the frames (since there is a minimal freight component for a second set of pcbs). This will make our project look more professional and easy to assemble. I expect to do the same for the motor mounts too.

    I am presuming a set of 2 frame mounts (3.5" dia) drilled for Quad & Hex frames plus 4 or 6 sets of 2 drilled engine mounts should cost ~$10-~$20. Unfortunately they will be green pcbs. Who is interested and is there a price point??

    From what I have seen, the motor mounts are either 3 or 4 way holes, so I will include both. Any dimensions would help. I will use a round disk like the frame disk.

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    Links to other interesting threads:

    · Home of the MultiBladeProps: TriBlade,·RamBlade,·SixBlade, website
    · Single Board Computer:·3 Propeller ICs·and a·TriBladeProp board (ZiCog Z80 Emulator)
    · Prop Tools under Development or Completed (Index)
    · Emulators: CPUs Z80 etc; Micros Altair etc;· Terminals·VT100 etc; (Index) ZiCog (Z80) , MoCog (6809)·
    · Prop OS: SphinxOS·, PropDos , PropCmd··· Search the Propeller forums·(uses advanced Google search)
    My cruising website is: ·www.bluemagic.biz·· MultiBlade Props: www.cluso.bluemagic.biz

    Post Edited (Cluso99) : 3/25/2010 6:41:04 AM GMT
    My Prop boards: P8XBlade2, RamBlade, CpuBlade, TriBlade
    Prop OS (also see Sphinx, PropDos, PropCmd, Spinix)
    Website: www.clusos.com
    Prop Tools (Index) , Emulators (Index) , ZiCog (Z80)
  • Robert TRobert T Posts: 71
    edited March 2010 Vote Up0Vote Down
    Cluso99

    I am in for the pcb and motor mounts.

    Did we every decide on which language (beside routines in assembly)? Or does it matter?

    Yes the Quadpowered boards are pricey. Thought it was a nice example with a pretty complete feature list and FOUR Propellers.
  • Richard S.Richard S. Posts: 70
    edited March 2010 Vote Up0Vote Down
    Clusso

    I have been following this thread with interest.· If boards + etc. become available I would be interested in buying one.· My interest is more in the hex/octa 'copter designs·as discussed on the MikroKopter web site.



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    Richard in Grants Pass, Oregon
  • Cluso99Cluso99 Posts: 13,024
    edited March 2010 Vote Up0Vote Down
    RobertT: Code would be a mix of spin and pasm although there is no reason we could not use Catalina (C) but I think we will not have enough hub ram for that.

    RichardS: Apart from the Octa, what else is required that is different to what we propose? BTW the MikroKopter iw way cool smile.gif

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    Links to other interesting threads:

    · Home of the MultiBladeProps: TriBlade,·RamBlade,·SixBlade, website
    · Single Board Computer:·3 Propeller ICs·and a·TriBladeProp board (ZiCog Z80 Emulator)
    · Prop Tools under Development or Completed (Index)
    · Emulators: CPUs Z80 etc; Micros Altair etc;· Terminals·VT100 etc; (Index) ZiCog (Z80) , MoCog (6809)·
    · Prop OS: SphinxOS·, PropDos , PropCmd··· Search the Propeller forums·(uses advanced Google search)
    My cruising website is: ·www.bluemagic.biz·· MultiBlade Props: www.cluso.bluemagic.biz
    My Prop boards: P8XBlade2, RamBlade, CpuBlade, TriBlade
    Prop OS (also see Sphinx, PropDos, PropCmd, Spinix)
    Website: www.clusos.com
    Prop Tools (Index) , Emulators (Index) , ZiCog (Z80)
  • Roy ElthamRoy Eltham Posts: 2,156
    edited March 2010 Vote Up0Vote Down
    I built a rack thing out of some of my VeX parts, and did some tuning and testing using just "half" of my quadrotor. I've been dialing in the software and got what I think are some good results so far.
    Here's a video of a test run. http://www.youtube.com/watch?v=J4uUMMo9l78

    I've run down the batteries for tonight so I had to stop there.

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    Check out the Propeller Wiki·and contribute if you can.
  • BuildThingsBuildThings Posts: 31
    edited March 2010 Vote Up0Vote Down
    @Cluso

    I am in for 2 sets of all boards. This is one of those projects that will always need some spare parts. smile.gif

    9DOF News:

    I received 2 boards on Saturday, however after 3 nights of yanking out my hair trying to replace their demo code with the DIYdrones code...Sparkfun confirmed they had loaded the ATMEGA168 bootloader by mistake vice the ATMEGA328.

    Since I need to build myself an AVR programmer tonight... I hope to have some data later this weekend.

    Anyone know how to bit bang a bootloader from the Prop? I read some posts on DIYDrones that Old Man Earl had done it, but never found any code.
  • Timothy D. SwieterTimothy D. Swieter Posts: 1,608
    edited March 2010 Vote Up0Vote Down
    I recall seeing a thread either in the Propeller forum or the Sandbox forum about Atmel boot loading from a Prop. Try Google's advance search and narrow the site list down to forums.parallax.com.

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    Timothy D. Swieter, E.I.
    www.brilldea.com - Prop Blade, LED Painter, RGB LEDs, 3.0" 16:9 LCD Composite video display, eProto for SunSPOT, PropNET, PolkaDOT-51
    www.tdswieter.com
    Timothy D. Swieter, P.E.
  • Cluso99Cluso99 Posts: 13,024
    edited March 2010 Vote Up0Vote Down
    Just been out to buy carbon fibre square tube. My favourite hobby store has gone belly up. The alternative does not have any in stock. Third one is closed. I have bought a Deanes plug/socket to connect to my battery (1650mA 3S1P LiPo) and the 3.5mm bullet plug/sockets to connect to my single motor BM2409-18 and W25A BESC. I already had these parts for an unfinished EPP flying wing.

    I am going to leave my "+" frame longer and allow the motors to slide out on the arms. This way I can experiment with an optimal location which of course will be set by motor power and prop size.

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    Links to other interesting threads:

    · Home of the MultiBladeProps: TriBlade,·RamBlade,·SixBlade, website
    · Single Board Computer:·3 Propeller ICs·and a·TriBladeProp board (ZiCog Z80 Emulator)
    · Prop Tools under Development or Completed (Index)
    · Emulators: CPUs Z80 etc; Micros Altair etc;· Terminals·VT100 etc; (Index) ZiCog (Z80) , MoCog (6809)·
    · Prop OS: SphinxOS·, PropDos , PropCmd··· Search the Propeller forums·(uses advanced Google search)
    My cruising website is: ·www.bluemagic.biz·· MultiBlade Props: www.cluso.bluemagic.biz
    My Prop boards: P8XBlade2, RamBlade, CpuBlade, TriBlade
    Prop OS (also see Sphinx, PropDos, PropCmd, Spinix)
    Website: www.clusos.com
    Prop Tools (Index) , Emulators (Index) , ZiCog (Z80)
  • Robert TRobert T Posts: 71
    edited March 2010 Vote Up0Vote Down
    I ordered motors, propellers, ESCs and some rectangular aluminum tubing. Might be a week before I get them though.

    Motor: E-sky EK5-0002b Brushless Outrunner 1000 kv, 45 grams
    ESC: E-Flite 25 Amp
    Propellers: 12/4.5
  • Cluso99Cluso99 Posts: 13,024
    edited March 2010 Vote Up0Vote Down
    RobertT: The props are a big aren't they??? I am going for 3 blade 8x4 (as suggested by someone earlier in this thread).
    What size aluminium are you using? The carbon fibre I am looking at range from 8-10mm sq/rectangular.

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    Links to other interesting threads:

    · Home of the MultiBladeProps: TriBlade,·RamBlade,·SixBlade, website
    · Single Board Computer:·3 Propeller ICs·and a·TriBladeProp board (ZiCog Z80 Emulator)
    · Prop Tools under Development or Completed (Index)
    · Emulators: CPUs Z80 etc; Micros Altair etc;· Terminals·VT100 etc; (Index) ZiCog (Z80) , MoCog (6809)·
    · Prop OS: SphinxOS·, PropDos , PropCmd··· Search the Propeller forums·(uses advanced Google search)
    My cruising website is: ·www.bluemagic.biz·· MultiBlade Props: www.cluso.bluemagic.biz
    My Prop boards: P8XBlade2, RamBlade, CpuBlade, TriBlade
    Prop OS (also see Sphinx, PropDos, PropCmd, Spinix)
    Website: www.clusos.com
    Prop Tools (Index) , Emulators (Index) , ZiCog (Z80)
  • Timothy D. SwieterTimothy D. Swieter Posts: 1,608
    edited March 2010 Vote Up0Vote Down
    I don't mean to cross post, but for those interested in GPS units I posted in the Sand Box some units I am selling which may work well for your drone concepts: http://forums.parallax.com/showthread.php?p=893910

    I kept a couple units for when I get time to pursue my own unmanned vehicle projects.

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    Timothy D. Swieter, E.I.
    www.brilldea.com - Prop Blade, LED Painter, RGB LEDs, 3.0" 16:9 LCD Composite video display, eProto for SunSPOT, PropNET, PolkaDOT-51
    www.tdswieter.com
    Timothy D. Swieter, P.E.
  • Roy ElthamRoy Eltham Posts: 2,156
    edited March 2010 Vote Up0Vote Down
    So, I managed to fry one of my LISY300 modules. I'm not sure what happened, but when I hook it up now the voltage regulator gets very hot and it doesn't work. The other LISY300 and H48C still work fine, and they were all on the Protoboard together sharing power, ground, clk, and data wiring. It was probably my "less than optimal" power setup where I was using a jumper wire to connect between the ESCs BEC output and the 5v of the rest of the board instead of proper wiring with a switch.

    Anyway, I am ordering a new one (and some other stuff since I can never buy just one thing from the Parallax store, it's just not possible [noparse]:)[/noparse], and I am "on hold" with my quadrotor project until I get the new stuff.

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    Check out the Propeller Wiki·and contribute if you can.
  • Robert TRobert T Posts: 71
    edited March 2010 Vote Up0Vote Down
    Cluso99

    The propellers could be too big, but they were out of the 10/4 propellers. They are sold in pairs for counter rotating motors. These are the ones sold at nghobbies for the mikrocopter. They come in 8, 10 and 12 inch diameter. The motor I bought is also used on the mikrocopter, so I am assuming its ok.

    Aren't third blade propellers less efficient than two blade props.

    The aluminum tubes are rectangular 1.5" x .75" x .125" 24". I ordered from onlinemetals.com. This is not meant to be my final frame though.
  • Cluso99Cluso99 Posts: 13,024
    edited March 2010 Vote Up0Vote Down
    I don't have any idea about prop sizes or no of blades. However, I note that propeller aircraft use multibladed props so I presume there is a reason or they would only use 2 blades. I think the 3blades look nicer on a quadcoper.

    The aluminium section seems huge. I am talking about 10mm rectangular tube which is ~0.4".

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    Links to other interesting threads:

    · Home of the MultiBladeProps: TriBlade,·RamBlade,·SixBlade, website
    · Single Board Computer:·3 Propeller ICs·and a·TriBladeProp board (ZiCog Z80 Emulator)
    · Prop Tools under Development or Completed (Index)
    · Emulators: CPUs Z80 etc; Micros Altair etc;· Terminals·VT100 etc; (Index) ZiCog (Z80) , MoCog (6809)·
    · Prop OS: SphinxOS·, PropDos , PropCmd··· Search the Propeller forums·(uses advanced Google search)
    My cruising website is: ·www.bluemagic.biz·· MultiBlade Props: www.cluso.bluemagic.biz
    My Prop boards: P8XBlade2, RamBlade, CpuBlade, TriBlade
    Prop OS (also see Sphinx, PropDos, PropCmd, Spinix)
    Website: www.clusos.com
    Prop Tools (Index) , Emulators (Index) , ZiCog (Z80)
  • BuildThingsBuildThings Posts: 31
    edited March 2010 Vote Up0Vote Down
    The general rule is that when replacing a 2 bladed with a 3 bladed prop, you select a 3 bladed prop that is 1 size lower in Pitch or diameter from the engine recommendation.

    Matching the entire power system is important, especially if trying to duplicate results among our models. The power system includes the battery, motor, and prop. Changing any of the power system parameters will alter the performance and capabilities.

    I think we need to come up with an estimate of total weight so we can compute how much thrust we need. Then we can pick the proper KV motor and use its recommended propeller.

    As an example of pitch differences ; a 10 X 8 and 10 X 4 prop spinning at the same RPM will have the aircraft with the 10x8 prop traveling (theoretically) twice the distance in the same amount of time.
  • Cluso99Cluso99 Posts: 13,024
    edited March 2010 Vote Up0Vote Down
    BuildThings: Thankyou for the 3 blade size info. I have been looking at 7x4, 8x4 & 9x4 3-blades as these are avail with counter-rotating versions.

    At the moment everything seems to be a guess from the airframe system. I would be happy if you could step in and make some recommendations.

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    Links to other interesting threads:

    · Home of the MultiBladeProps: TriBlade,·RamBlade,·SixBlade, website
    · Single Board Computer:·3 Propeller ICs·and a·TriBladeProp board (ZiCog Z80 Emulator)
    · Prop Tools under Development or Completed (Index)
    · Emulators: CPUs Z80 etc; Micros Altair etc;· Terminals·VT100 etc; (Index) ZiCog (Z80) , MoCog (6809)·
    · Prop OS: SphinxOS·, PropDos , PropCmd··· Search the Propeller forums·(uses advanced Google search)
    My cruising website is: ·www.bluemagic.biz·· MultiBlade Props: www.cluso.bluemagic.biz
    My Prop boards: P8XBlade2, RamBlade, CpuBlade, TriBlade
    Prop OS (also see Sphinx, PropDos, PropCmd, Spinix)
    Website: www.clusos.com
    Prop Tools (Index) , Emulators (Index) , ZiCog (Z80)
  • SzabiSzabi Posts: 58
    edited March 2010 Vote Up0Vote Down
    It’s not easy to make the right decision for props and motors but there are some facts wich needs to be taken in consideration.
    (This are the most important "googled" together information smile.gif I know that some part is pretty clear for anybody, but I would like to help to anyone else who may a lack of knowledge)

    Power
    torque = rpm * turning-moment
    P = Voltage * Current
    Consumed Sys power is P = Battery voltage * Current measured before the ESC
    Hints:
    In case of a BLDC:
    Voltage ~ rpm
    Current ~ turning-moment

    Losses
    Electrical loss goes higher in case of higher currents. Current is depending on the voltage and the coil Resistance of the motors
    Loss = I² * R.
    Losses are lower in the ESC’s since there we have some loses occurred only by the included diodes (approx 0,7V)
    ESC loss = I * 0,7V
    There are some more losses caused by the Ohmic resistances in the Batteries and wires all of this will raise in proportion with the current.

    Efficiency
    In case of a 16V-Battery we have a higher efficiency of ESC / BLDC than in case of a 12V-Battery.
    Why? Because a with a 16V battery can deliver the same Power with less Amps (P = U * I)
    In this case a Motor/Prop-combination needs to be calculated for 16V.
    (4s-Lipo is approx. 16V, 3s-Lipo approx. 12V)

    ESC Efficiency
    An ESC unit can deliver more power when powered with higher voltages.
    Ex.:
    For an ESCS with Burst Current of 20A and a Continuous Current of 10A
    For a 3s we get 240W peak and 120W continuous
    For a 4s we get 320W peak power and 160W cont
    For a 6s we get 480W peak power and 240W cont

    Hint: Higher currents mean higher losses and higher magnetic fields, which can affect our compasses for example.
    Higher Voltage means less Current (for the same power) less losses and herewith lower magnetic field.

    Props
    There are 2 main values by a propeller, Diameter and Pitch.
    The pitch gives us a theoretic value, the distance how much a propeller could travel upwards during a single rotation.

    A prop with a smaller diameter needs more rpm but less turning-moment to produce the same thrust as in case of a bigger prop.

    A very important thing is the prop weight since we will need to change the prop speed as fast as we can (for a better stabilization). A higher weight prop has a bigger inertial-moment.

    RPM/V
    Rotation Per Minute / Volt.
    It’s a value, which differs from band to brand (even by the same motor parameter)
    Ex: A motor with 1000KV @ 5V should mean 5000RPM without any load (without props)
    @ 10V should mean 10000RPM
    Is good to know that with bigger propeller or higher voltages we need less KV for the same thrust.
    It is also to be mentioned the fact that John said. “The general rule is that when replacing a 2 bladed with a 3 bladed prop, you select a 3 bladed prop that is 1 size lower in Pitch or diameter from the engine recommendation.”
    Ex.:
    A 2 blade 10x4.5 prop is equivalent with a 9x4.5 3 blade prop

    Self-induced voltage
    In a motor in the similar way as in a generator a self-induced voltage will be generated.
    Self-inductance is defined as the induction of a voltage in a current-carrying wire when the current in the wire itself is changing. In the case of self-inductance, the magnetic field created by a changing current in the circuit itself induces a voltage in the same circuit.
    Using a motor without a propeller in a normal case According to Lenz's law, the induced current must flow in the opposite direction of the primary current. The induced current working against the primary current results in a reduction of current flow in the circuit. As soon as the motor will have a load (by using a prop) the induced voltage will be less therefore the Current will increase.
    Some examples:
    An ESC set to a 10% PWM and ESC draws 1A at 10V (so power is 10W)
    The motor has a too high KV or too big propeller installed on it and is inducing only 1V.
    The result is that our ESC needs to handle a 10A (10W/1V) induced current. This is the reason why ESC goes hot.

    Battery
    The following things could be important:
    Voltage: 3s = 3*4.2V = 12.6V (under load will deliver approx. 11.1V)
    Capacity in mAh: A 2200mAh can deliver 2.2A for an hour or 4.4A for 30minutes
    Maximal Current (C): 2200/20C means 20 * 2.2A = 44A
    And of course the weight ☺

    The Right Choice
    LiPo + ESC + BLDC + Prop combination should be well tuned together.
    The prop should be count as less as possible
    The chosen combination should produce a thrust needed for hovering by a lowest Current as possible.
    We should have enough spare. Possibly Max. thrust should be at least 2x hover thrust but best if 3x.
    Even during max load (2x or 3x hover thrust) should LoPo, ESC and BLDC not be overloaded.

    Finally
    Optimal choice is a BLDC/Prop combination, which during full throttle (delivering aprox 2-3x hover trust) should not be overloaded herewith should not draw too much Current (means that LiPo and ESC should not be overloaded)

    Ex.:
    Let’s say in case of a QuadHeli with a 2200/20C Lipo a good BLDC/Prop combination would be which on full throttle will not draw more than 11A. Also is should not draw more than 5A/BLDC during high load.


    I hope this was useful

    Post Edited (Szabi) : 3/30/2010 7:41:32 PM GMT

  • Cluso99Cluso99 Posts: 13,024
    edited March 2010 Vote Up0Vote Down
    Thanks szabi. I misunderstood that a 20C Lipo menat 20A max. So this is much better. I have thought to use only a 2S to start with but from what you are suggesting we should go for a 3S. I saw some nice 3S 35C from HobbyCity that should work. I have no idea what thrust we will require. Maybe tomorrow I can buy the frame parts and this will give me the missing info to calculate the weight.

    Do you have any ideas for weight and therefore motor/esc/prop/battery combination ??

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Links to other interesting threads:

    · Home of the MultiBladeProps: TriBlade,·RamBlade,·SixBlade, website
    · Single Board Computer:·3 Propeller ICs·and a·TriBladeProp board (ZiCog Z80 Emulator)
    · Prop Tools under Development or Completed (Index)
    · Emulators: CPUs Z80 etc; Micros Altair etc;· Terminals·VT100 etc; (Index) ZiCog (Z80) , MoCog (6809)·
    · Prop OS: SphinxOS·, PropDos , PropCmd··· Search the Propeller forums·(uses advanced Google search)
    My cruising website is: ·www.bluemagic.biz·· MultiBlade Props: www.cluso.bluemagic.biz
    My Prop boards: P8XBlade2, RamBlade, CpuBlade, TriBlade
    Prop OS (also see Sphinx, PropDos, PropCmd, Spinix)
    Website: www.clusos.com
    Prop Tools (Index) , Emulators (Index) , ZiCog (Z80)
  • SzabiSzabi Posts: 58
    edited March 2010 Vote Up0Vote Down
    Hi Cluso!
    ·
    yep, C means it can discharge C times its capacity :-) That's why 11A is the max load (2200x20 = 44.000mA=44A...44A/4motors = 11A per motor), so 5 is approx. half of 11, what a 20C lipo can easily deliver :-)
    ·
    I have no idea of the exact weight. My opinion is that we can rely on the·BLDC specs (thrsudt, current voltage) and once we get an idea about the weight we can choose the right combination based on my previous post.
    ·
    First of all I'm worried about props. ·I can't find any :-( I would prefer 2 blade props but is hard to find CW/CCW pairs. Probably I'm going to buy it from MikroKopter. Those props are 10x4.5 so, your choice of 3 blade 9x4 (GWS HD8040) is pretty much the same.
    I would like to use the same setup as you specified in one of your posts but only for its good price.
    It should be OK for a first run.
    Based on the TowerPro 2409-18T specs the motor is designed for ·8*3.8apc/8*6 props however the kit comes with a 9x4.7 one. A 10x4.5 will be definitely too big but some users tried it with a 11x4.7. hmm…
    The Voltage is 10V, so a 3S lipo is a bit high for it but 2S probably will not be enough since the props are also bigger then in specs…we need a lot of torque.
    I have some doubts with this kit but with no load and no acrobatics I hope it will be suitable for a prototype.
    Considering a maximum current of 20A (according to the BLDC specs) a 25A BESC should be OK.
    If we trust Burton Hatch (see review) the 16A is almost normal for the motor which means the motor is not overloaded. (if he is using 3S ..with a 2S he will smell smoke very soon J )
    In this case a 3000/40C battery is just enough (120A). On full throttle it may reach the max of 20A (20x4=80) that’s the more than half what your battery can deliver but still OK. A 1800/40C will blow up (72A)
    ·
    As I said this is not the best choice but should be fine for the beginning. A better combination I calculated on the weekend is on my other notebook which I left at my company. I will post it tomorrow. That will cost approx. 250USD (if I remember correctly) for 4BLDC, 4ESC, 1LIPO which I don’t really want to pay for it J

    however…a good choice of motor/prop/ESC/Lipo would make things easier (for example calibration, fine tuning before first filght etc.…in my opinion)
    ·
    Calculating with approx 2Kg we need something like
    BLDC’s with the following parameters:
    3-4s
    approx 700-900KV
    Max Current 10A
    designed for approx 10x5 2blade props
    thrust min. 650g (better around 800g)
    Lipo:
    3-4s / min 2000/20C
    ESC:
    20-25A
    ·
    this will rock J
    ·
    ·
    Damn…It’s a hard decision.
    ·
    Sz
    ·
    ·
    ·
  • Cluso99Cluso99 Posts: 13,024
    edited March 2010 Vote Up0Vote Down
    Szabi: Thankyou for all your thoughts. IIRC the 3blade counter rotating props 7x4, 8x4 & 9x4 are available from hobbycity·"HC"·in HK.

    HC also have Turnigy Lipos 3S 1800mAh 40C $15.90 168g and 3S 3000mAh 40C $28.35 278g

    25A BEC is ~$12 so they should be fine.

    The TowerPro 2409-18T are used in flying wings here at 3S (11.1V) and that is what was recommended. Do you have a better motor·suggestion??? I guess if I burn it up I will rewind it - from discussions I have seen, this improves the performance anyway as hand wound with care is much better.

    It is cheapest for me to get all my gear from hobbycity in 1 shipment.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Links to other interesting threads:

    · Home of the MultiBladeProps: TriBlade,·RamBlade,·SixBlade, website
    · Single Board Computer:·3 Propeller ICs·and a·TriBladeProp board (ZiCog Z80 Emulator)
    · Prop Tools under Development or Completed (Index)
    · Emulators: CPUs Z80 etc; Micros Altair etc;· Terminals·VT100 etc; (Index) ZiCog (Z80) , MoCog (6809)·
    · Prop OS: SphinxOS·, PropDos , PropCmd··· Search the Propeller forums·(uses advanced Google search)
    My cruising website is: ·www.bluemagic.biz·· MultiBlade Props: www.cluso.bluemagic.biz
    My Prop boards: P8XBlade2, RamBlade, CpuBlade, TriBlade
    Prop OS (also see Sphinx, PropDos, PropCmd, Spinix)
    Website: www.clusos.com
    Prop Tools (Index) , Emulators (Index) , ZiCog (Z80)
  • SzabiSzabi Posts: 58
    edited March 2010 Vote Up0Vote Down
    Well guys I spend some hours to find the best combination for a reasonable price. ( I don’t post my original 250USD setup because there are things out of stock ☹ )
    There were many things I took in consideration. Price, hobbycity stock, etc….

    A good BLDC would be the TGY AerodriveXp SK Series 35-36 910Kv / 310w (16,62USD)
    Kv: 910rpm/v
    Shaft: 4mm
    Weight: 112g
    Rated Power: 310w
    ESC: 30A
    Cell count: 3~4 Lipoly
    Suggested Prop: 10*7, 11*8.5, 12*5
    This is a good choice and it will work very well with the 9x5 GWS HD9050 3 Blade Prop (2,99/2,79USD) too.
    Based on the tests I saw it will produce a thrust of approx. 1Kg @ 16-17A with a 3s LiPo

    If we are calculating with 17A / BLDC 4x17A = 68A
    For this I would recommend the Rhino 2550mAh 3S 11.1v 40C LiPo (34,79USD), which should be ok for the beginning. (I would be more happy with a 3000mAh lipo but no stock at the moment)

    An ESC for this setup would be the TURNIGY Plush 30amp Speed Controller (or the 25Amp version) (15,4USD)

    The BLDC/ESC/Prop combination would cost 1,45 Prop + 16,62 BLDC + 15,4 ESC = 32USD it’s approx 10 dollars more than your setup Cluso but this one is much powerful and safer choice. The full sys including Lipo will cost like 163USD
    (for dose who will upgrade later is still spare in this small BLDC’s we can use 4s lipos and bigger props later if needed)

    This 4 motors should lift up 3-4 Kg easily and the full setup weight is approx 780g, so we have a lot of spare for frame, camera etc.

    I will post a cheaper but weaker version as soon as I reach home. ☺

    Can somebody post me more info about TowerPro motors? The thrust is still in question by this motors :-(
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