Pirx Seven – The ultimate custom 7-inch FPV frame, part 1

Do you know this old saying “If you want something done right, do it yourself”? I do and sometimes I just live according to it. Not always, I’m not crazy, but at least from time to time!

I fly 7-inch FPV drones a lot. To be honest, they are my favorite flying devices. There are a few good 7-inch frames, like TBS Source One for example. There is a difference between good and great tho. I do think that Source One is a good frame, there are a lot of things on it that do not make me very happy tho! The list might not be very long, but it is relevant:

  • props in the view
  • limited space to install split-like hybrid cameras
  • no very convinient place to install VTX
  • it’s not that big inside as one might imagine…

Because of that, and because I think I know how to do it (I’m an engineer) I’ve devided to design and manufacture my of 7-inch FPV drone frame that would fix what I do not like in Source One.

This is how Pirx Seven was born!

Pirx Seven - 7-inch FPV drone frame

  • Dead Cat configuration
  • Plenty of space inside for everything you want! There is even a place in the back to fit the whole 30x30mm stack!
  • Place for Split-like hybrid camera in the front
  • Attachable mounts for antennas, GPS and other accessories
  • Clear, unobstructed view for HD camera like GoPro on the front deck

So far, I was able to mill a prototype unit to test it in flight. So far so good, I really have to say that I like what I designed.

Pirx Seven - 7-inch FPV drone frame

Fully assembled frame weight 205g with steel screws and aluminium standoffs.

Pirx Seven - 7-inch FPV drone frame

What next? Test flight and some changes. The full list consists of 12 points in total and basically means that I will have to redesign almost everything…

If you want to know why the name and what does Pirx stands for, here is the answer. It’s a tribute to Polish writer StanisÅ‚aw Lem and his book Tales of Pirx the Pilot.

3D Printed Impeller Fan aka Centrifugal Blower

I have a 3D printer and some CAD skills, as well as basic engineer training. I never studied fluid dynamics, but I also never studied running a website or how to be a father, but here I am.
Anyhow, I want to put an impeller fan (yes, not a turbo) on an airplane and use it as a propulsion system. After a few days with CAD software, I came up with a small 3D printed impeller fan that hopefully will be strong enough to make airplanes fly…
The centrifugal fan is power from a “standard” drone brushless motor and a standard RC ESC. It sounds terrific!

Turboplane aka squirrel-cage propulsion

Today it’s time for the next brave step: to maiden this awkward airplane powered by a impeller centrifugal fan and check if it works. To be honest, I’m not that optimistic about it… The efficiency of 3D printed squirrel-cage fan is non-existent and the whole setup generates only around 200g of thrust. In theory, it should be enough to make the airplane fly, but I’m not so sure about it…

FPV drone with a pusher prop | DIY Pentacopter!

Here it is Penta Engine Nitro Incredible Ship – P.E.N.I.S. Or shorter: Willie. OK, let’s be serious for a moment. It is a pentacopter. A normal 5-inch FPV drone based on Martian II frame with the 5th motor attached in the back. When I flip a switch, the 5th motor starts and it flies almost like an airplane. It’s a VTOL. The idea is not mine and a few years ago there was something called Foxtech Screamer 250.

Thrust vectoring on a flying wing

If modern fighter jets can have thrust vectoring, maybe RC flying wings also can get one? I’ve decided to test this theory and equip my very old DIY Depron flying wing with a motor tilting mechanism that allows changing the vector of an RC brushless motor and propeller and vector the thrust. My goals were:

  • check if it works at all
  • check if thrust vectoring would improve the flight
  • check if pitch control can be done only with thrust vectoring
  • check if yaw control can be done this way

QmuBeacon – open-source Arduino GPS locator/beacon drone is now public

If too long didn’t watch: it’s a GPS equipped beacon/locator DIY system based on popular radio development boards compatible with Arduino: LoRa32u4 and ESP32 LORA32 working in 868/915MHz band using LoRa modulation. You put a beacon on anything you want to track: airplane, drone, car, boat, wife, husband and use Locator to get distance and heading. Both beacon and locator are battery operated and should have a range of a few kilometers in the air.

Flying R2-D2 or SpaceX Falcon 9? Both – RC coaxial dualcopter

The second generation of my 3D printed coaxial dualcopter is here! And this time it works almost as I wanted.

3d printed RC coaxial dualcopter

Just watch the video

On the more technical details:

  1. It runs INAV 2.0 with a custom mixer
  2. Thrust and yaw control is provided by 2 counter rotating propellers
  3. Upper motor is 2205 2300KV with 5×4.5×3 propeller rotation in CW direction
  4. Lower motor is 2205 2600KV with 4×4.5×3 propellers rotating CCW
  5. Control surfaces are rotated 45 degrees from the long axis to fit servos
    flight controller is also 45 degrees rotated
  6. Any 9g servos will do
  7. runs on the 4S battery that has to be on the top of the device
  8. All 3D printed parts can be downloaded from Thingiverse

Required parts:

  1. 2205 2300KV brushless motor
  2. 2205 2600KV brushless motor (2300 also will do but will have less yaw authority)
  3. 5×54.5×3 propeller
  4. 4×4.5×3 propeller
  5. 2 14mm carbon pipes (12mm internal diameter), each around 270mm long
  6. 2 2g servos
  7. 3M bolts to secure the motors
  8. good adhesive tape to make control surface hinges
  9. pushrods
  10. hot glue
  11. flight controller compatible with INAV
  12. radio receiver

3d printed RC coaxial dualcopter

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.

3D Printed Tricopter Drone

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

3D Printed Tricopter Drone

3D Printed Tricopter Drone

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

3D Printed Tricopter Drone

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