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sectrix's blog
Posted by sectrix | Mar 19, 2010 @ 02:28 PM | 1,819 Views
Posted by sectrix | Feb 12, 2008 @ 08:30 PM | 7,970 Views
An idea on how to make a starter/generator circuit. When switching to live power, the generator relay will switch on first, then the battery relay will switch to the charger. When going back to battery, it will first switch on, then the generator relay will switch to start. The DC/DC will need to be able to take both of the sources at once. The system defaults to battery/start mode, in case the engine dies in flight.
Posted by sectrix | Feb 08, 2008 @ 12:10 PM | 1,908 Views
I've found the camera and Tx/Rx I plan to use on RangeVideo. I'll use their 1W 2.4 GHz transmitter and their standard receiver. I like their IF FPV camera, and have heard nothing but good things about it, so I'll use that too.

The electrical system is a bit tricky. Relays will switch the motor between the ESC and a full-wave rectifier. Problem is that as soon as the avionics switch from batteries to live power, they'll lose power for an instant. Which means the relays will too, which means they'll probably never be able to switch. To get around this, I'll have to apply both batteries and live power for a second, then switch off the batteries. I'll also have to not charge the batteries until they are not providing any power...

It isn't as hard as I thought it would be, but I'm gonna need a lot of relays. I'll post a block diagram as soon as I make it.
Posted by sectrix | Jan 31, 2008 @ 09:18 PM | 1,934 Views
Took notes on chapters two and three. These first three chapters were on the basics of motion, lift, drag and the boundary layer. I now know much on how to calculate and think about the basics of a planes motion and the forces acting on it in flight. The next chapter is called 'Basic Model Performance Problems' and I assume it will teach me how to fit these ideas together into designing an actual plane.This seems likely because the chapters after that are about more specific topics, such as reducing vortex-induced drag, choosing an airfoil and things like that. And it is as long as the previous three combined. In the end this book will only teach me about the theory of how model planes work, and not actually about how to build one. For that I found a apparently great series of books by Harry Higley that is all about the practical side of designing and building model aircraft. So I have purchased his 'Master Modeler', 'Harry's Notebook' and 'All About Engines' books. I'll post something here after reading through one.

My organization of this project has changed somewhat. Also, after going through some of the new resources I found recently, and some more thought, I have also more or less decided what'll be included.

Airframe-Frame and gear.
Learning about how to design this right now. Will be single engine and slow and stable; easy to fly. I hope to also make it able to take a large payload for any sort of future projects. I'd also like to include an external refueling...Continue Reading
Posted by sectrix | Jan 15, 2008 @ 11:01 PM | 2,169 Views
After research and discussion on the forums, I've learned a few things.

First, the laws on UAV operation in the US seem to be a gray area. I was technically correct about my previous assumption, but as someone here pointed out AC 91-57 is, after all an advisory circular. A suggestion of rules to follow, encouraging voluntary compliance. I will still be complying with 91-57s rules, but not with the added mention of line-of-sight operation in the other document. I believe in the end, should the law come down, it will be noted that the plane was not hurting anyone or anything, it was done in the spirit of academic pursuit, and I made it as safe as I reasonably could, and will be exonerated from any penalties. I hope.

Further research into the electronics of the plane have been made and I've found that my video system is hideously expensive. I have found other systems of equal or greater quality for much less; future hobbies, new generation hobbies, etc. I am also debating the need for a full telemetry system. It is very expensive and just another radio signal my plane must emit. If it is possible to use the control radios bi-directionally I may be able reduce the radio links needed to two. I have discovered 'OHD's that post some metric data into the video. Not as complete or as accurate as I want, but perhaps all I need. Also there is the question of video display; if I should use a simple LCD panel or a set of goggles. Goggles preclude a panel of switches for things...Continue Reading
Posted by sectrix | Dec 28, 2007 @ 06:09 AM | 1,887 Views
...the 401 is still grounded and I have given up on my build-the-whole-plane approach. Numerous problems with what I was thinking before. I could design and build the whole plane, but the amount of learning and extra cost and time it would require to make the electronics is vast. Especially when everything I need is sitting in a box somewhere for like $150.

On the positive side, the idea of this UAV is much more solid in my head. I have sorted out the obvious issues, and just have to get to work to find the ones I don't know about. I've done a lot of research and thinking, and this is what I've got it down to.

The general idea is a remote controlled airplane that I can fly up to about ten miles away using a live video and telemetry feed. This will consist of five systems on the plane, and four on the ground. The first three systems are common to both the plane and the ground; video, telemetry and control. The plane has two additional systems, an airframe and an autopilot. The ground also includes a base station.

This is obvious, it is a video link from the plane to the ground. WirelessVideoCameras.com sells video camera and Tx/Rx packages for around $700 - $1000. They have ranges varying from 1000' to 25 miles, and are built specifically for RC aircraft. The camera is also optimized for the conditions it will mostly see: pointing at the sky. The Rx on the ground has a simple yellow RCA video connector, and is NTSC compliant so I can use whatever video screen...Continue Reading
Posted by sectrix | Apr 24, 2006 @ 11:21 AM | 2,599 Views
Ugh. UPS is not a great job. Let me rephrase that. In some ways it's a great job, in most others it is deplorable. I'll start with what I like. Medical benefits and tuition reimbursment right off the bat. Fairly high starting pay, considering the only prerequisite is you graduated highschool. Internal promotions always take precidence. Free poptarts and rice crispies treats on Friday. But, otherwise this job sucks. I start at 4 AM and continuously move usually heavy packages for five hours. I get yelled at when a supervisor tells me to do the wrong thing(but I'm always thanked at the end of the day....wierd). It gets friggin hot. I make barely enough money to stay afloat, much less expand into this FPV airplane project, or my other projects. I still have yet to repair the Firebird, and thats hardly expensive at all. I really need some flight hours under my belt, and I cant fly. I cant even get a RC flight simulator for my Macintosh because one doesn't exist (barring Helis). So, I decided to get a second job. Without it, it would take months to save enough money to fix the Firebird. And after I master this, I want to get a gas trainer kit, and a good set of electronics. Right there is something like $400. Soon, in order to advance any longer in my study of electronics, I'll need to get test equipment. At least an oscilloscope and signal generator. Maybe even a frequency analyzer since I want to try and design the radio controls for my plane. That's all a lot of money, at...Continue Reading
Posted by sectrix | Apr 02, 2006 @ 04:12 PM | 2,622 Views
I went from doing nearly a chapter a day in the text book to doing almost nothing. Since I last wrote I have only completed one other chapter, pulse response of resistor-capacitor circuits. I've been unproductive due to my buddies band's website finally going up. I offered to build it for them, and I had to spend some time getting it up and running properly. The 401 is still grounded on account of the tail section.

My lack of money hasn't gotton another one yet. When I order it. I'll probably get two sets of wings and an extra tail as well. I finally got a job recently at UPS. Crappy hours (3:30 AM to 8 AM), but enough spending money for a college student plus tuition reimbursement and medical coverage. I work an easy shift too; primary sort is a no-brainer. UPSers know what I mean. Not much else has happened. I finally got my first issue of Model Aviation, which was somewhat interesting. I haven't really learned much more about the FPV project. I wonder just how much of my avionics will be home-made. There seems to be a lot of great equipment out there at reasonable cost, as far as telemetry and data transmission are concerned. But it is still unclear to me how it will all interconnect, what sort of system I will use for control (if, indeed, regular RC aircraft TXs and RXs are out of the question for the range I wish to achieve), RC redundancy issues, and of course, the legal restrictions on FPV aircraft.
Posted by sectrix | Mar 23, 2006 @ 11:54 PM | 2,885 Views
Studied a bit more on electronics. Not as much as I would have liked to, but the past four days or so, I've been doing very little because I over exerted myself while lifting with my friend. My arms and chest were stiff and painful for 96 hours. I didn't feel up to doing much, and couldn't concentrate anyway. But today I finished what I started a few days ago. I did the chapter on capacitance and another on frequency responce of RC circuits (thats resistor-capacitor circuits, not radio control). Next is pulse responce of RC circuits. After that I move to the mystical field of inductance. The SMA-401 is still grounded, I have no money to replace the tail section. I was able to stiffen the wings I believe, with extra strength packing tape applied across the creases. I then rebalanced them and cleaned 'em up. Hopefully they don't fold on me. I took a closer look at the rest of the aircraft. There is some crumpling starboard side near the rubber nose; doesn't seem to be important. And it looks like the spar rotated somehow in it's socket; there is evidence of bent plastic on the fuseloge spar holes, and the circuit board seems somewhat stressed where the spar touches it. Nothing I can really do about this.......except not crash.
Posted by sectrix | Mar 17, 2006 @ 04:16 AM | 2,655 Views
The amount of learning involved in radio control and telemetry electronics is vast. I know a little about DC circuits already, so I have some idea of what I do and don't know. My basic instruction is coming from a 1980's Floyd electronics textbook. This will bring me up to speed on the math involved in circuit analysis, and teach me things I dont know too much about yet, like AC circuits, impeadence, electric fields, etc. Not enough for designing working RC circuits, but enough for basics. The next step from here is practice designing circuits, with the Radioshack electronics lab. Also, further learning will be accomplished with another book I have, "The Art of Electronics". The entire Floyd textbook is covered in the first chapter of 'The Art of Electronics', so this will show me many more advanced topics, like MOSFET's, ICs, common microprocessors, low power design, etc. Anyone serious about electronics should own this book. And finally, to really get good coverage, the ARRL handbook will explain all I ever needed to know about radio. And I mean EVERYTHING is in this book.

So at the moment I'm still on the Floyd electronics textbook. Trying to work through it at about a chapter a day, doing all the problems I have answers to. I've covered DC resistance circuits and analysis methods, and have just breached AC circuits and signals. The next chapter is capacitance, which should be exiting since I know almost nothing about it!
Posted by sectrix | Mar 17, 2006 @ 03:43 AM | 2,737 Views
Flew at the preserve near my house again, a better field the any others previous. A somewhat calm day, with 7 to 12 MPH winds. The first flight was mostly uncontrolled, with a typical nose dive landing. The second flight however, was my first controlled landing although the flight was again, recovery after recovery. After this I switched off the ACT and had my first controlled flight followed by another good landing. The fourth flight went well, but somehow I stalled yet again and fudged the throttle and sent it at the ground at about 15 degrees with a whole lot of speed. The rubber nose hit first and caught most of the impact, but caused the plane to flip onto the tail and over again on the wing(thank you inertia). The tail is damaged beyond repair, and must be replaced with a HBZ7031 for about $10, and the port wing is severly bent, and must be stiffened or replaced with HBZ7020 for about $15.

This brings me to drastically reconsider my approach to learning to fly. The next flight should be to take off, gain a little altitude, trim it out and land. No turns, nothing fancy. And no ACT either. It seems to yank away control at random critical moments. Then proceed to adjust the plane until I'm certain it flys well at neutral control. Only after its adjusted well should I try and take off, gain altitude, bring down the speed a bit and try turns. But I have no money to replace the tail yet, so I must wait ...
Posted by sectrix | Mar 17, 2006 @ 03:28 AM | 2,795 Views
Finally flew at a decent place clear of obsticles. A calm day too, 5 MPH winds are all I can hope for around here. First flight was better then most, but still resulted in uncontrolled landing. Second flight was going rather well, but after a particular stall and recover, I jerked the stick all nasty (thumb turbulance, as someone here said ) and went into a full power dive at 10 feet or so, just enough to gain decent airspeed...right into the port wingtip. Broke right off at the bracket. I was dismayed, no more flying for today, probably need a whole new set of wings. Days of downtime. But after closer inspection when I got home, I found that although the wing broke off, most of what held it together was the wing spar bracket anyway. The braket has 52 little spikes on each side that clamp the wing when screwed together, and the wing simply pulled out from the spikes. Unscrewed it, put it back in, a little tape on the leading edge, and I was good as new.
Posted by sectrix | Mar 17, 2006 @ 03:18 AM | 2,840 Views
There were six attempts today at the same place I flew last time. Not quite as windy as the first day, around 9 MPH with 12 or 15 gusts. However its the smallest amount of wind in some time. Flights were longer than the first, and higher, but all ended in an uncontrolled landing. Lost the landing gear after the second flight. The last flight, the plane was carried a good ways downwind and out of site. Since I'm not that great of a pilot I'm not sure weather the ACT had any part to play in this, but it seems I definatly lost control for a second there. Could also be that they gave me a channel 6 version of the Freedom, and I didn't know enough to realize that this particular channel is shared with CB radio... No damage to the plane, but stress marks are visible on the wings.
Posted by sectrix | Mar 17, 2006 @ 03:03 AM | 2,769 Views
Maiden Flight. I really should have waited, but I was too itchy. Winds steady at 10 MPH and gusting at 20. Flew at the forest preserve near my house.Bad day for flight. Three attempts at flight, all ending in uncontrolled landing after less than 10 seconds of flight time. No damage appearent. I should wait for a much less windy day.
Posted by sectrix | Mar 16, 2006 @ 07:56 PM | 2,386 Views
First an introduction.

My interest in RC planes has grown exponentially the last few months. There's a few reasons for this. First off, I've always had a fasination with airplanes. Every aspect of planes were awe inspiring to me. The cockpit was full of buttons, switches, dials, levers; an orgy of technology. The powerplants were huge, loud, and powerful. The design of the fuselage is all curves and planes. The first plane I fell in love with was a B-17G flying fortress. I built a model of one, and when I finished it and could hold it in my hands and observe all the little curves and nuances........ I almost cried. She was beautiful. Everything, the proud nose, window bubbles, powerful wings loaded with props, rounded edges, and something like 13 12.7mm guns.... It inspired me to look up history of these planes. Their crews swore by them. 'She'd fly with one engine and half a wing.' seemed to be the common consencus. Anyhow, that was my first real love affair with planes. I was 12. 9 years later, the interest has built again. Not in heavy bombers, but in avation. I was thinking of doing some more plastic models again, and was browsing some websites when I came across RC planes. That was cool, but didn't exite me to any great degree. Later that night I was thinking about RC planes when an ad for wireless CCTV came on. Heeeeeeeeeey.... that sounds like a cool idea, a live camera feed from a model plane...hmmmm. After some thought and research I learned that that this had...Continue Reading