Hello FT community!
Today I will describe my setup in detail, so it might be useful for someone willing to build one of these. Let's start!
Specs say a lot about airframe, so let's dive right into it!
Battery: Turnigy 3000mah 3S 20C
Motor: Park 450 1200kv
Prop: APC 9x4.5
ESC: Hobbyking 30A (with blue heatshrink)
Servos: Hitec HS-65HB
Flight Control: APM 2.5.2 with Power Module, GPS and MinimOSD
Receiver: OrangeRX OpenLRS with dipole antenna
VTX: 1.2Ghz 200mW from rmrc with cloverleaf antenna
Flight cam: PZ0420H without IR filter
KK DIY variometer
tbeacon DIY UHF emergency beacon (more on this further down)
Flight time: 20 min
Cruise speed: 40-50 kph
Max. speed: 80-90 kph
Trip distance: 18-20 km
I've built mine out of depron with some water-based glue which comes out very lightweight when it dries. In order to reinforce the wing and add some stiffness I used some cardboard and a wooden spar to stiffen it. The whole wing is filled with expanding insulation foam to add an immense amount of crash-resistance and taped with packaging tape.
The winglets are held by some small but strong 5x5x3 and 5x5x5mm neodymium magnets. This way they won't snap and break on landing as they would if they were glued to the wing. You just pick them up and put back on the wing.
This photo shows foam-filled wing and 2 magnets' positions.
There is a kind of a skid on the belly, makes launches very convenient. You can also see 4 huge screws for ballast. This is nowhere enough to balance it out.
In order to compensate for its natural tail-heavyness the motor was placed far further forward. But that wasn't enough. Even with big amount of ballast and having Gopro with its battery up in the front, the wing is still tail heavy and doesn't glide very well.
The motor/prop combo I use allows for good efficiency but not speed. The wing cruises at about 8-9 amps, thus it is able to cover quite a distance, and fly 8-9 km out and back despite having bad CG and being quite hefty.
The 200mw 1.2Ghz video system gives a great punch and very clear picture with no sudden static appearing in close range as you would get with 5.8. Video link quality is very predictable, it slowly degrades as you approach the range limit.
When flying FPV I find it very convenient to use a variometer, specifically when gliding with no power. Despite having an OSD overlay with all necessary information, an audible tone gives me the abulity to keep vertical speed (and thus horisontal airspeed) constant when gliding in manual mode without having to look at the values. Here is my vario:
It plugs into the VTX audio channel. Here is the LINK to RCG thread where you can find all info about it. Thanks KK!
Now what is that red thing there?
This is something absolutely awesome. I can't express how simple, cheap (this is especially important, right? haha) and valuable it is. Ready? It is the DIY(!) UHF locating beacon made from ORX OpenLRS RX module. I can bet you didn't know about it. Forget all those bluetooth tags and other short range c**p market currently offers us. This device is just a killer. In short, it plugs into your GPS, NAZA or MAVLINK data stream and grabs coordinates. Once your model is down, take your LPD/PMR radio and call it with 1750 hz tone ("tone burst" function in many radios). It will first tell you BY VOICE the strength of your radio's signal (thus it can be used without GPS (or in case GPS failed) to ''foxhunt'' the model), and then last known coordinates. Just go and pick your model up. The range is very good since it uses low UHF frequincies. I have been able to call it from 700 meters away in dense woods, and this is not even close to the range limit (but of course it depends on many circumstances). It can be furter improved by using directional antenna on the radio.
I use a 2 cell 180 mah lipo to power it. In current configuration it lasts for several days, which can be extended for up to a month (or reduced to a couple of days) by tweaking settings. You can find all info about it and firmware at tbeacon.org
This plane is almost 2 years old and never failed. Despite having bad CG by desing, it is good for relatively far & long FPV cruising. I plan to design and build custom hot wire cut wing about the size of the BN versa which will eliminate the CG problem and make a perfect plane for me. I have already ordered some parts for 4 axis CNC hot wire machine I will make.
Bonus video! This is the compilation of some flights I did with my wing. The second plane is FT versa (btw, with motor moved forward as well). Enjoy!