RC Aircraft

Pico Goblin FPV

Completed Model

Wanted to try to build the FT Nano Goblin, which is the Flite Test foamboard version of the Strix Nano Goblin FPV drone. However, I wanted something slightly smaller, and found in the forums people were printing the plans out at 75% size with good success. So I reduced the original plans to 75%, but then realized that this doesn't take into account the foamboard itself is still going to be 100% size, so I had to make some adjustments. When doing the fuselage cover, it didn't fit right, so looked and found other plans online and decided to just print out that. However, the size was off. Apparently I ended up printing it at like 66% size, not 75%. So I just figured it out and created the new cover that would work. This thing is really, really small - 50 cm wingspan. Since the foamboard size was going to affect the curvature of the wing airfoil, I didn't know if this thing would even fly. There is hardly enough room for all the hardware, the battery just fits in the canopy area diagonally, and as such doesn't require securing. There's no way to make it any smaller than this.

Was able to find a cheap video transmitter that would work with FPV goggles. I wanted to just have a standalone VTX and not have to run it through any sort of flight controller (there's no room for one anyhow). From the product page, it described it as being able to manually change the band/channel, which is what I would need to do to run it without a flight controller. After opening the package, it didn't come with any instructions on how to set the band/channel/wattage manually, so after searching, even the product website didn't have the information. Finally, after finding a product page on a Russian website, I was able to get the information I needed.

Tight Space Construction (4 images)

For attaching the camera and the antenna, I used some plastic card around the screw holes for reinforcment, since just the paper and foam is way too soft. For the first test flights, I decided to remove the antenna and just tape a weight of the same weight in place instead so if it crashed, it wouldn't destroy the foam where it was attached.

The maiden flight did not go so well. After watching the video, I determined I had the aileron rates set way too high. You can see I roll one way, then try to roll the other way to compensate, it over-rotates, I try to correct and over-rotate again, and then crash, all in the span of two seconds. Some hot glue was all that was necessary to repair it.

The second flight went better, but it was pitching down too much to be able to trim and fly it without crashing at the same time, so I had to bail early. Only slight damage again, just needed some more hot glue.

The third flight went even better, but still needed some elevator uptrim. It flew well, but the wind was gusting to around 20 mph, which was just too much for something this small to deal with. I was happy I was able to get it to fly without too much damage.

The next day it was calm out, so I decided to push it to see what it could do. The first crash in the video was from me losing plane orientation. The second was from me trying to do a roll, but didn't realize I had the rates so low. I open up the throttle close to full a little over halfway through the video. This thing is really fast. Amazingly it's still not completely dead, a bit more hot glue should give a few more flights. Can't wait to try this with FPV goggles.

Two Successful Take-offs and Landings

I have an ELRS receiver and a PWM module that will work with it that I will try once I get this tested out flying FPV.

Plans

Parts List

VTX Instructions

JMEMCU Tran-3016W Video Transmitter

Support 7-26V (2-6S) voltage input

Operating instructions: 1.Short press is to adjust the channel (corresponding to the blue light, 1-8, a total of 8 times); 2.Long press 2 seconds is to adjust the group (corresponding to the green light, A, B, E, F, R, a total of 5 times); 3.Long press for 5 seconds to adjust the power (corresponding to red light, 25,200,400,800,1600MW, 5 times); 4.Long press for more than 10 seconds is to open 11 prohibited USA channels; The default does not output prohibited USA channels: 5705, 5685, 5665, 5885, 5905, 5880, 5658, 5695, 5732, 5880, 5917

About the use of the keys (while referring to the frequency table in the later picture, the flight control needs to be configured with the JSON file we provide in order to achieve OSD tuning reference)

The new video transmitter comes with locked frequencies and bands! To unlock it, turn on the power, wait a few seconds until the video transmitter starts, briefly press the button (as for channel selection), release it, and then press and hold it for about 15 seconds until the red, blue, and green indicators light up simultaneously. After rebooting, the video transmitter will be fully unlocked!