Hand on: Flip32 F4 Flight Controller

Yesterday I've received new flight controller for my Reptile X4R 220 quadcopter: Flip32 F4 from ReadyToFlyQuads. This is my first contact with STM32F4 based flight controller and I'm really looking forward to see if it really puts a difference comparing to F3 boards like SPRacingF3 I've been using last few months.

Some features:

• STM32F405 CPU running at 168MHz
• MPU6000 gyro connected via SPI interface
• Integrated 1.5A voltage regulator
• VCP port
• 3 UARTs

Flip32 F4 (and Airbot F4 which is exactly the same board) is supported by Betaflight, RaceFlight (that due to some GPL violations I'm boycotting) and INAV (at the moment of writing this post INAV support is not complete) and REVO target. Well, basically, this board was designed based on OpenPilot Revolution stripped from radio modem, barometer and those JST connectors (pin headers rules!). There are some differences between Revolution and Flip32 F4 in terms of hardware (voltage regulator for example) or separate LED header (which does not work).

There are two "problems" I've discovered so far:

1. Whole board is getting very hot. Looks like it's because voltage regulator and battery monitoring are connected. You can not have one without the other even when you have BEC somewhere else
2. STM32F4 does not have built in inverters. That means, S.Bus has to be connected to UART1, since this is the only UART with external inverter

Although I've been able to install it on Reptile X4R 220 already, I have no idea how it flies yet. Weather outside is very rainy...

Hands on: JJPro P175 4" mini-quad

Thanks to GearBest I have a new quadcopter to test and review: JJRC JJPro P175 True-X 4" min-quad.

First of all, it is Ready-To-Fly (RTF) product. Everything required to fly is inside white box:

JJPro P175 comes assembled with accessories and radio transmitter:

Read more...

Marabou Stork is so ugly...

My Depron FPV airplane is ugly! Good thing is flies quite well...

Project Dualcopter - worklog #1

Flying season 2016 is slowly coming to an end on northern hemisphere. That means less time spent on an airfield and more time spent behind a desk. For this autumn I've found a very interesting, small project: Dualcopter.

Dualcopter is an UAV with two coaxial contra-rotating propellers and 2 control surfaces driven by servos. Lift and yaw are controlled by propellers, while pitch and roll by ailerons placed below motors. This video illustrates how it looks like:

My Dualcopter will be slightly different. Instead of foam and wood I will use 3D printed parts connected together CA glue and zip ties. Maybe it will not be super strong and probably will not survive any crash, but should be enough to make it fly for a minute or so. Almost all parts would be either 3D printed or taken from spare box. I'm not planning any new purchases.

Planned specs:

• Motors: Turnigy MT2213 935KV
• Props: APC 1045 MR
• ESC: Afro 20A
• FC: Flip32 probably with INAV inside
• Battery: 1300mAh 3S
• Weight: around 800g with battery

So far, after 2 evenings I have this:

Two motors mounted on a frame.

Next step would be to build bottom section with ailerons and battery compartment.

3D Print Timelapse Video

Few days ago I've decided to do something new: timelapse video of a 3D print. It's kind of fascinating to watch extruder places layer after layer of molten PLA... too bad it's taking so long to print something bigger...

• Printer: Malyan M150
• Thing: 35 deg RunCam HD / Mobius stand for mini-quads
• Filament: PLA
• Speed: 50mm/s

Hands on: DALprop T5046 propellers

Last weekend I had an opportunity to spend some time in the air with new DALprop T5046 propellers from Surveilzone.
They are "funny" propellers. On one hand they have some nice features, on the other, they have few flaws that almost disqualifies them in my eyes...

• Pros
  • Good air "grip"
  • Good efficiency
  • Smooth flight
  • Nice speed
• Cons
  • Oh man, they are fragile. Each crash equals at least one broken propeller. If you got used to "tough" props from DAL, you will be shocked
  • They are very, very sharp at edges. I've cut my fingers when I was unscrewing shaft nut. You either have to hold them very carefully or wear gloves?
  • Too flimsy. I was afraid that they will bend in flight and cut ESC. I've already lost 2 ESC because of flimsy/bendy propellers and I started to pay attention to "flimsiness"

Final conclusion: while they might be an interesting option in terms of performance, they are not prepared for everyday use!

Photo from Surveilzone

Tip: how to secure XT60 plugs

I had a problem with my SkyZone goggles: I was constantly breaking battery cable near XT-60 plug. One not careful enough grip and cable was ripped away. I've decided to fix it and permanently secure the cable with epoxy glue.

Sure, I could use hot glue (that looks ugly) or Sugru (that is expensive), but since few weeks ago I've bought HobbyKing Mid-Cure Epoxy glue, I've decided to use it instead. It worked fantastically!

Solder cables to XT-60 plug pretty close to external coating as possible.

Now, prepare a "mold" using electrical tape. Just wrap it around plug and cable leaving empty space inside. Prepare epoxy glue and pour it into "the mold".

After and hour or so, epoxy glue will be hard enough, that electrical tape can be removed. There is no chance I could ever rip this cable from the plug by accident!

INAV is learning to do mini-quad racing too

Let's be honest: in terms of mini-quad racing there is Betaflight (probably also Raceflight but I've never flew it yet, so will not comment on its flight performance), long long gap, and then it's everything else including Cleanflight, LibrePilot, INAV etc.

Originally INAV concentrated on "big" UAVs with GPS capabilities. After all NAV in name stands for Navigation. Mini-quads and acro performance were left alone, and once again, let's be honest: comparing to Betaflight, it sucked. It was possible, I've even written a short tutorial how to set it up, but it sucked.

Luckily, it is changing. INAV 1.2 had brought some improvements like Iterm limiting and acceleration limiting, and Acro flying in INAV became very nice. Small revolution, or maybe bigger catch up, is planned for INAV 1.3: asynchronous gyroscope, accelerometer and attitude processing. I've been working on it for last few months and results are very promising: INAV can drive a mini-quad with Betaflight comparable performance. Like this (please remember I'm not the best pilot!)

Setup:

• PID task frequency: 1kHz
• Gyro task frequency: 2kHz
• Accelerometer task frequency: 120Hz
• Attitude task frequency: 100Hz
• Frame: Reptile X4R 220
• Motors: EMAX RS2205 2300KV
• Propellers: DALprop TJ5045
• Flight controller: SPracingF3
• Firmware: INAV 1.2 with custom changes

Hand on: DAL (DALprop) TJ5045 propellers

After moving to new, 4S powered, mini-quad based on Reptile X4R 220, EMAX RS2205 2300KV and FVT Littlebee 20A, I've discovered that I'm missing some power. DALprop 5040 and DALprop T5040 I've been using on 3S did not delivered enough power. So, I've gave DALprop TJ5045 a try.

According to specs, they should be most efficient from all DAL 5045 family. Well, efficiency will be determined, one thing is sure: they surely give much more thrust and pitch speed comparing to T5040.

Thrust and speed improved a lot. ATM, hover is at about 32% of throttle and climb rate is impressive. I love it! They also seem to be little quieter that T5040.

They are also durable. Maybe I'm not crashing as often as before, but when I do, it's much more spectacular. Today I had two of those spectacular crashes and all propellers survived. Nice.

Marabou Stork: FPV airplane maiden flight

For the last few week I've been little busy building my next fixed wing UAV: "Marabou Stork" Depron/Carbon/3D Printed airplane with pusher prop build for FPV. It's improved version of "Red Cruiser" model from last year.

It's equipped with KFm-2 wing, Turnigy D2826-6 2200KV motor, APC-E 7x4" propeller, 2700mAh Lipo battery, FPV setup with MinimOSD and RunCam PZ0420H camera. And Flip32 running INAV for stabilization and navigation (no GPS yet).

As you can see on a video above, it flies. Even pretty well. It needs some tuning, but have big potential. Unfortunately elevator malfunction grounded it after few minutes in the air.