Monday, November 19, 2012
FPV if you didn't already know means First Person View. In this case it means we fly a remote controlled aircraft from a view as if we are in the cockpit of the aircraft. In this article we will develop a series of scratch built FPV systems. The first is a low budget small version. Built to take abuse that will be present in the learning sequence of flying your first FPV aircraft. It also had to be small to be portable enuf to be transported on my bicycle side bags. I designed the S3 flying wing just for FPV operation. so that's were I already started FPV as you can see in the development of the S3 in my other article. See: http://wings.surething.biz/2013/12/s3-mini-wing-design-and-test-history.html for more details about the S3 wing and how to build one. The S3 has now passed preliminary flight tests without FPV equipment installed and is now ready to be a stepping stone to try FPV. I just ordered a minimal FPV video transmitter with video cam and pair of Fatshark Goggles and a minimal OSD from Hobbyking.com to give it a try. included in the list of parts ordered is: Fat Shark PredatorV2 RTF FPV Headset System w/Camera and 5.8G TX product id: 253000014 HobbyKing E-OSD product id: E-OSD Turnigy 500mAh 2S 20C Lipo Pack product id: T500.2S.20 total cost $321 You could start a bit cheaper if you didn't start from goggles but for me that's a must as I can't carry a video monitor on my bicycle. It has to all be small and portable for me to be able to use. I expect to receive the package from Hobbyking in about 10 days. I will add to this article when the parts come in and we start to flight test it with FPV. I did add a spread sheet CG calculator into the S3 docs that will be used to determine were we can mount the added transmitter, battery and camera when I get them and measure how much they really weigh. I hope to at least partly embed the added parts into the wing of the S3 to keep it clean in the air stream. I also want to put as much separation from the r/c remote receiver antenna and the 5.8ghz video transmitter as possible to prevent RF interference and yet still keep the wing as stable flying as possible. This first FPV will have very limited range to maybe about 1000 meters from the operator. I'll try to keep it within 600 meters or less when I operate to be seen by a copilot that will be watching the plane without goggles. I have two friends here in Pattaya that I met at our local field (names Tom and Nick) with more experience with video transmitters on 5.8ghz than myself and I hope to get some consultation and assistance from them in setting things up and testing. As I will only have one full system setup if anything fails it would be hard to isolate what's at fault without a second set. Thanks to my fiends we should be able to isolate between transmitter and receiver problems and fully test each part individuality and compare performance to what Tom and Nick already have in there inventories. Tom has already pushed his max successful video link to about 8 km or more, 8 times what I presently hope for in this first project. I think there will be a learning curve as to being able to fly with this new perspective. I'm not sure how hard it will be or how long it will take to learn. I think maybe I'll setup an FPV flight school to teach new pilots how to fly FPV. This will provide people with a chance to try before they buy new equipment and prevent damage to persons and property by people with no experience jumping in without knowing the risks. It would also be like an adventure ride for people to enable them to see things that they only dreamed possible. I think today FPV is like hanggliding was in like the year 1977 where you would build or buy a hangglider and jump off a cliff to learn how to fly it without ever having a lesson from an instructor. We would read in the news paper about another fatal crash in a hangglider every few months. I later learned how to fly hanggliders by the way, WITH a teacher. So that's why I know the importance of flight school. If your interested in FPV flight lessons let me know so I can get a count of the number of people interested in my aria to see if we can make it possible. Ok that's it for now check us out in about 10 more days when hopefully we get the needed parts from hobbyking. Update Dec 12, 2012 5:33pm: It took longer than expected to receive the hobbyking.com order but today it's come with the parts listed above. So all I had to do is charge up the batteries and plug them into the goggles and transmitter and it just instantly worked. I also did a quick test of video input from my satellite video box that puts out standard PAL video signal from an RCA jack (the fatshark package came with the RCA adapter plugs and cable). The image looks fantastic both from the satellite TV tuner and the video transmitter. I will later do a ground range test to get an idea of how far it can go. I will first put together the transmitter with 500mah battery and the camera into some kind of foam padded box structure, just so that it's one part to test on the ground. I guess I could make this box aerodynamic so I could just pop it onto any plane but for now we just want a quick test. I will also need to find out how long both the batteries in the goggles (1000 mah) and the transmitter cam battery (500mah) last with continuous power on. As far as my airframes go, both my present planed FPV aircraft are out of service. One has a bad motor and burned ESC (the big M2 wing) , the other smaller S3 wing just needs an ESC. So I'm totally out of ESC and will need at least one to get one of my planes in the air. So we will take care of that tomaro morning. I already was offered a 40A ESC from Nick for 300 baht so hope to see him tomaro also. Paul also offered me a used ESC for 300 baht so I hope to pick up those two and maybe one more from my local hobby shop that want 320 for a crappy 30A mystery brand. OK That's all I got for now. I'll bring back range numbers measured with my gps later today. The other thing is that the video transmitter channel dip switch is covered with the plastic covering. So I think I'm stuck with channel 1 unless I cut the plastic back. I will live with this until I find a reason to change it. Update Dec 14, 2012 5:45am: Before my first flight with the help of Nick the now fpvschool.com certified instructor, we did a ground range test of the S3 wing with the video transmitter turned on. Nick wiggled the elivons as I walked out to about 1500 meters. He then wiggled the elivons faster to signal that the video signal was getting noisy. So that sounded good enuf to flight test as that's farther than I normally fly my R/C plane. Also Nick said that it will get better range from the air than from the ground as there are less abstractions. My first flight with FPV goggles was harder than I expected. My first flight with the S3 with the video camera I launched it in normal R/C mode and got it up to about 150 meters or more directly over head. I then put on the goggles and started flying for about 10 seconds. It seemed OK for a bit but then I started loosing it so I decided to remove the goggles and bring It back. That was much harder than I expected. It took me another 4 seconds to have a clue were the plane was. By the time I found it in the sky it was only 20 meters off the ground. I was able to recover and land it OK. So that when I realized I wasn't going to do this alone. So lucky I had Nick to help me. The next flight I had Nick just track the plane as I flew it with the goggles and he would just provide verbal feedback as to what I should do this ended up worse than the last flight as I lost perspective I tried to remove the goggles and by the time I found the plane it was only 2 meters above the ground. It ended up not being able to recover and crashed out in the bushes. I went and recovered the wing that was about 100 meters from where I was flying and found it had found some nice soft tall grass to land in with no damage at all. So that was lucky. So the third flight this time I had Nick fly the plane as a standard R/C and I just watched with the goggles as he flew it. I would then just take over the controls for a time as he continued to track it and provide me with verbal feedback as to the direction he wanted me to steer to keep it within visual range. When I would loose it I would tell Nick and he would simply take over the controls and bring it back. This seems to work much better. At least I'm we aren't crashing. But it seems I have a lot to learn with many more flight before I get it handled. One problem is the S3 wing is a bit small and unstable for a beginner to learn on. The video equipment makes it even more unstable in it's present method of mounting as a pod and the added 90 grams of mass. The CG is pushed a bit more forward and the glide is bad. Later I also broke the spare in the S3 when I was flying it as a normal R/C from a high G turn so I didn't get any more flights of FPV today. So from what I learned I will try some computer simulation that now hooks to my present R/C radio to see if that helps my skills . I also need to get the M2 wing that is bigger and more stable working. Also if I expect to be able to train myself without Nick or someone else helping me all the time, I will need to get the autopilot system installed , tested and working. So I could also test the autopilot on the S3 wing before I get the parts presently needed for the M2 wing. With the autopilot in the S3 I could also try the fly by wire mode that might help to learn to fly FPV. With fly by wire the autopilot can control the altitude and the human just changes the direction with the stick. Problem with the S3 and the autopilot system plus the video equipment is that the added wing loading might be pushing the limits of the S3 wings ability for stable flight. To get the M2 wing working as FPV we need a bigger motor that I can't seem to find in the local shops here. I've been asking people at the field like Paul if he had one to sell but nothing yet. So I may need to setup another order with Hobbyking.com before the M2 becomes flyable. On an added note for some reason I couldn't see the video transmission from Nicks FPV aircraft. He says he's on 5.8Ghz but I scanned my Fatshark 5.8ghz goggles across the spectrum and see nothing. He also uses the spironet antennas that I presently am not using yet that are polarized differently. I'm not sure if that could be why I don't see him or maybe his system has a wider range of frequencies in 5.8ghz that he is now set to. We never tested to see if he could pick up my video signal on his receiver. Later in the day I was able to see someone else's video signal from a new small RTF quad that one of the Thai guys at the field just got that operated on 5.8 ghz band.