EMAX RS2 2206 1600KV motors hands on

Think about an electric motor for your 5 (or maybe even 6) inch acro or FPV racing quadcopter. What do you see? Something in a 2205-2306 size range with a KV rating somewhere 2300KV and 2600KV. Sometimes even more. And it works great, as long as you wat 5-inch props and 4S batteries. You can choose and choose and choose between different models of different manufacturers. But what if you want to go 6S or 7 inches? You have a problem. Very limited choice of motors (and propellers as well).

Luckily, it starts to change and you can actually but lower KV 220x and 230x motors. I got my hands on EMAX RS2 2206 1600KV since I'm not very happy with TBS Endurance I'm using on my 7-inch endurance drone. They seem to be missing some torque and when I've found that new low-KV (1600KV is still a lot) EMAX motors, I did not waited long to order. I love RS2205S and RS2306 and hope RS2 will not disappoint me.

What can I say about EMAX RS2 2206 1600KV before installing them on anything? (so far I got only 2, the second pair is on a way)

1. They finally changed those plastic boxes to something smaller
2. RS2 2206 1600KV look good for sure. Black and Red!
3. No bottom cap since, well, you do not really need it after all
4. 29g with wires
5. 4mm shaft made from titanium (at least they say so)
6. Bearings are 8x4x3 if I can measure
7. They kept this nice screw in the bottom instead of a c-clip
8. Mounting holes spacing has changed! Instead of a standard 16x19mm it is 16x16mm now! Check your frame. The great majority should accept 16x16mm but there might be some rare ones that will not!
9. Single wire winding. Looks ok, TBS Endurance has a nicer winding tho!

How will EMAX RS2 2206 1600KV behave in the air driving 7-inch propellers? work? Good, I hope...

How to flash FrSky R9 Mini, R9 Slim and others with your radio

FrSky is not making things simple with R9 long range system. New firmware appears quite often and there is no way to flash receivers over the air. You can use some PC software, passthrough from FC and things like that, but from my perspective, as long as you can get to the receiver itself, the simplest way to flash R9 Slim and R9 Mini is to actually connect them to Taranis or Horus and do it from the radio itself. How? Like this!

Good 7-inch multirotor propellers, where are you?

7-inch endurance FPV drone is my new thing. There is one little problem tho: good 7-inch low pitch efficient propellers. The choice is that there is almost no choice at all! The list of 7-inch propellers with a pitch or around 4" and preferably 2 bladed (efficiency) is as follows:

• Gemfan 7038
• HQProp 7x3.5x3 V1S
• Gemfan FLASH 7042

And I already know that some those above are total crap!

3D Printed Tricopter, part 1

In the last two weeks, I had plenty of time to sit in front of Fusion 360 to design a few things, but no time to 3D print anything. As a result, I have a couple of almost ready projects. Yesterday I showed you 3D Printed Dualcopter Reloaded. Today I will show you 3D printed tricopter drone. Tomorrow? Who knows...

Last year I have designed and made a fully printable quadcopter frame called Isando. It was fun, but well... There are plenty quadcopter frames over there. Cheap and much stronger than anyone can print at home. But Tricopters? Good luck with that.

I've taken some of the parts of Isando Quadcopter frame, designed some more and here it is.

The most important part of any tricopter is, of course, the tail motor tilting mechanism. I had the following options:

• no bearings, just bushings
• single bearing and using the servo as a second support point
• two bearing and the servo is used only as a torque source, not support point

Guess which option I've chosen? Right... The tail will be quite heavy, so to somehow help with that, the rear motor has enough space to use 5-inch or 6-inch propeller. And the rest? The rest is quite standard:

• Standard FPV camera in the front
• 30.5mm hole spacing flight controller in a middle
• video transmitter and radio receiver just behind the flight controller
• ESCs on arms
• 5-inch props in front
• 5 or 6-inch props in the back

Of course, I will share STL files but only after I will print and assemble this thing. So please wait a little longer.

3D Printed Dualcopter Reloaded #1

The first generation of my 3D Printed Dualcopter was not the best. It was flying. Somehow. Poorly. Crashed. But for a moment it was flying alright.

I'm slowly designing the second generation of Dualcopter. This time smaller in scale since instead of 10-inch propellers, it will be using 5-inch ones. And smaller 2205 motors. And some carbon fiber to support 3D printed elements and hopefully give it a little more structural strength.

The general idea is as follows:

• "Structure" will be provided by two vertical carbon pipes
• Motors and propellers will be in a duct. Not EDF, but almost. The idea is not to get more efficiency but to guide the air to the control surfaces. The goal is to have some control during descend too. Version without duct had none
• Upper motor will be 2205 2300KV with 5x3 3 bladed propeller
• Lower motor will be 2205 2600KV with 4x4 3 bladed propeller
• Lower prop will be working in the already accelerated air so it needs more pitch speed. More RPM and higher pitch = higher pitch speed
• 4S battery on top to move the center of gravity far from control surfaces to give them plenty of torque
• 2 9g servos
• flight controller running INAV

And that is more or less all... Will it work better than the previous one? I hope so :)

Eachine TX805 5.8GHz 800mW video transmitter hands on

I have something like a personal problem with "the best FPV transmitter manufacturer". It's about ideology. So, when a few weeks ago I had to order a few 5.8GHz transmitters, I had something like a problem. With TBS Unify Pro on my "not wanted" list, the "wanted" list got somehow short.
I do own a few Matek HV VTXes and I'm quite happy with them. But I can not always buy the same thing, so when I saw Eachine TX805 for slightly more than $15 I've decided to give it a try.

It appeared in the mail today and here are some first thoughts about it.

First of all, it's slightly bigger than I expected and in fact, it almost looks like a clone of Matek HV VTX. Not that it's bad or something, it's just not what I expected.

RF circuitry is shielded. And that is good. I only wonder if there is any kind of thermo-pad between shielding and RF components. I hope since at 800mW heat can kill electronics pretty easy. I like MMCX connector since u.fl sucks so much. I also like the fact that all the connectors are solderable. I prefer that over JSTish connectors. A pretty bulky choke allows me to suspect that built-in 5V voltage stabilizer of the camera is at least decent as well. On the other hand, soldering on MMCX does not look "high quality". But hey, I got it for $15.99, I can not expect too much, right?

What else in a box? RP-SMA pigtail, whip antenna, and a short manual. It's a nice touch about that manual. It's quite nice and written in understandable English language!

Eachine TX805 5.8GHz 40CH 800mW video transmitter specification:

• Frequency: 5.8G
• Channels: 40CH
• Input voltage: 7V~24V
• Serial protocol: Smart audio (licensed? But can you really license a protocol?)
• 5V output for Camera
• Output power: 25mW/200mW/600mW/800mW switchable
• Antenna connector: MMCX
• Cable connector: Solder pads
• Dimensions: 36mm22mm5mm, 30.5mm hole spacing
• Weight: 8g without antenna

I got mine Eachine TX805 from Banggood

INAV OSD Profiles - because one OSD layout is not enough

INAV 2.0 changes a lot. Including OSD. One of the new functions is something called "OSD Profiles". You can set up 3 independent OSD layouts to radio switches and change them during flight. One OSD profile can display all the data, second one minimal set of data and the third one Map or Radar mode.

The news, Butterflight is dead and Cleanflight did not resurrected

In this episode of "Drive and Talk":

• Cleanflight is dead
• Butterflight is dead or dying. Depends on a view
• I'm building a Ritewing Mini Drak
• I'm rebuilding Nano Talon
• I'm building an airboat
• I'm building a 3D printed paddleboat
• I'm thinking about building a 18650 capacity meter

ESP32, Arduino and EEPROM memory

ESP32 MCUs can be a great replacement for popular ATmega328 Arduino boards, but they are somewhat different. Even if ESP32 Espressif Arduino core is used, some of the libraries will not work out of the box.

Just like EEPROM will not work without changes. Mainly because ESP32 does not have EEPROM memory. An external flash is used instead.

Good thing, ESP32 EEPROM library distributed together with Espressif ESP32 Arduino core solves this problem in a quite nice way. All you have to do is to call EEPROM.begin with a size of emulated storage size in bytes as an argument. From there, everything goes as before.

Do It Yourself liquid soldering flux

Do you know you can make your own liquid soldering flux? And possibly flux pen refill for cheap? All you need is some solid soldering rosin and 95% ethanol alcohol. Cheap, kind of dirty, but works...