Updates – 9/27/12

I now have the flight control board, the Naze32. It was surprisingly small, the picture on the website was bigger then this thing really is. For a size comparison, I set it on the keyboard of my laptop.
Uploaded from the Photobucket Android App

That was nothing compared to the FrSky telemetry link that came with it.
Uploaded from the Photobucket Android App

I have hooked the board up to my computer and with the MultiWii GUI interface I could see the sensor outputs changing as I moved the board around, so everything seems to be working.
I’m at school right now, but over the weekend I plan to do the following, including documentation here on my blog:

  • Pick up a cheap multimeter from Harbor Freight for testing components.
  • Finish my JR6201 72Mhz to 2.4GHz FrSky conversion.
  • Cut the sheet of plywood for my quad base, and glue on 1/2 inch square, 24″ long basswood arms (yes, another design change).
  • Update the firmware on the Naze32 and learn the interface so I know what to do when I have my quad built and I’m eager to fly.

I’ve got a whole lot of research left to do, mainly stuff that applies to FPV, when I’m ready to get that set up. But I’ll tackle that when it comes to that. I believe FPV will be really, really fun.

A Frame Design Change

The other day, I stopped at the hardware store to see if they had small pieces of wood, and their selection of aluminum caught my eye. I pulled out a hollow square tube and while it was extremely rigid, it was also too heavy. However, I’ve seen lots of stuff with holes drilled down the length to lighten it up, so at school on yesterday I stopped by to ask my Engineering Statics teacher how much holes reduced the strength of material and such. I never actually asked him, as I started telling him what I wanted it for, he asked some questions on weight and thrust, and then recommended I use some basswood about the dimensions of an average wood yardstick (1″ x 0.25″?), oriented vertically. Then, because it would want to vibrate left and right as it’s narrow, simply get some fishing line and run it from one arm to the next all the way around, making a square of the fishing line. A quick sketch is handy.
I just used Paint, as I’m feeling too lazy to make a better one in Sketchup. The arms and plate will be made out of wood, no aluminum is planned now. The red line indicates the location of the fishing wire which stabilizes the arms from moving in the horizontal direction. Making it this way should make it pretty light.

My teacher also told me if I want it really light I use a simple truss instead of solid wood, and we start talking about simple truss’s in class tomorrow (now today, Friday). I said I would, but not until I know how to fly good, I don’t want to spend hours making a truss only to destroy within minutes it cause I crashed on my first flight.

My prop balancer arrived today. Looks pretty nice, although I haven’t used it yet. I’ll report back on how I like it once I have props to use it with.

On Wednesday I ordered a 5kg digital kitchen scale, so that I can weight parts as I go along, measure motor thrust, and try different frames in the future to find the lightest ones that are still strong enough for use. Less weight equals less power needed for flight, and less power needed equals longer flight times. I also just recently found a post on RCG that said that for a given frame, the longest flight time will be with a battery that weights the same as the frame does. So lighter frame also equals smaller battery, which is cheaper, and cheaper is always good.

About three hours ago I got an email from HobbyKing, saying my package is packed and sent to shipping, and to allow 48 hours for tracking information to appear on the website. So as long as it doesn’t get stuck in customs, it shouldn’t be too much longer…

First Quad Frame – Initial Planning

Frames seem to be easy enough to make; easy enough that spending $25+ for a prebuilt frame doesn’t make much sense to me. I’ve seen a number of DIY frames on RCG, and while they can be built fancy and expensive with carbon fiber and the like, many people make them out of aluminum and/or wood, PVC, etc. Many frames are constructed with the arms in an X, and usually sandwiched between two squares of material to hold them. This also provides a platform for the electronics and battery. Here’s an example I found with a quick Google search: (Click to go to his Flickr page for a description)
DIY quad-copter
The L-brackets at the ends of the arms appear to be blade guards, and are the first time I’ve seen a blade guard like that. Most don’t have blade guards, and mine probably won’t either. As long as you keep it at a safe distance you don’t have to worry about it. Note that he does have a “sandwich” of two plates, the one on the bottom is just smaller.

This is what I came up with last night, using Google Sketchup:
The plate is 6″ square, and the arms extend about 6″ outwards from the corners and are 0.75″ square. They most definitely might vary on the final design, or after testing, but they seemed reasonable. I plan on using a sheet of aluminum and wood arms, mainly because I have some scrap pieces of sheet aluminum and wood is cheap. I’m not sure yet what I’ll use for landing gear, but I was thinking that if I go with wood arms I will just use a short vertical piece of the same size wood on the ends of the arms. Many people use helicopter landing gear, as the person in the example picture did, which has the benefit of a neat, clean look and doesn’t weigh much. Gear with a wider footprint is desirable for a beginner in RC helicopters, and so I will use the same reasoning for my quad. Quads, after all, are nothing but a helicopter with four blades instead of two.

I did not mention in my first post, but there are two additional things that I ordered for the quad already.

  1. A flight control board (FCB). This is the brains of the quad. I bought the Naze32, available from AbuseMark.
  2. A prop balancer. I bought a Top-Flight TOPQ5700. This model holds the propeller vertically on a horizontal shaft which itself is held up by two magnets, giving a very low friction shaft, allowing the heavy side to be determined so that the propeller does not cause vibration while in spinning.

It’s going to be around two weeks, at least, before I get my order from China. I plan to continue working on this frame, so I can fly sooner once the order finally comes in. Also, I am partially completed in the conversion of my transmitter from 72 MHz to 2.4 GHz, and I will cover the conversion as well when that is completed.

Lets Get Started

I started this blog a while ago, thinking my posting style on Facebook would be better suited to a blog rather then spamming my friends News Feeds, but I never did get around to doing anything more then making the blog. Not a single post. The reason I am actually posting now goes back a little ways.

Back in ’06, before I was old enough to even have a driver’s license, let alone before I even began that one day, I would live on my own and have my own blog, my dad bought an R/C airplane. It was a Soarstar, available by Hobby Lobby International Inc, (not to be confused with the Hobby Lobby chain store), and was based on another design, the Wingo, and had no brand name, as clones generally don’t. My dad had flown some RC sailplanes back when he lived with his dad, and wanted to return to the hobby. He retrained himself to fly and then trained me, and I was hooked.

For the next two years, we enjoyed flying, albeit with greatly differing flying styles. I didn’t want to fly the “boring” sailplanes he was interested, and he had no interest in the sportier side that caught me, eventually leading to 3D flight. I had started with the SoarStar, but then migrated to the Great Planes Super Sportster EP. This was an electric version of a plane originally designed for flying with an internal combustion engine, was heavy and underpowered. It really needed a brushless motor, and although I was sent a second plane due to shipping damage, I never completed the brushless conversion on the repaired first plane. Instead I got an ElectriFly FlatOut Foamie for my birthday, and basked in the glow of 3D flight. The plane itself was a complete and utter design failure, and the foam cracked from in-flight forces, but I repaired and strengthened it and had a blast. When it was beat up too much, I transferred the electronics to a 3D foam model I found on RC Groups (RCG) which I constructed out of the blue foam made by the DOW Chemical Company for siding houses. Had a blast, the foam was much better, needing only a hot glue gun for repairs. I also had an Eflight Blade CX2 I flew around inside the house. Life was good.

However, this stage mostly ended when, do to a couple of reasons, my dad did not renew the membership to the club. I flew for a little while on the edge of my small town, but my dad did not have the proper space to fly his sailplanes and so rarely flew, I could get none of my friends interested in flying, and flying one plane by myself became stagnant and slowly I lost interest, ending in a crash. About a year later I had the urge to repair it, and did, and crashed it on my first flight as I was no longer used to flying and lacked the skills I was used to. The plane went on a shelf, untouched, and rarely thought of except for small, ignored thoughts of possibly repairing it some day.

Fast forward to ’12. I’m now legally able to drink, and I’ve been living in a two bedroom apartment with a roommate for more then a year and a half, working full time as a security officer, riding my motorcycle, volunteering on the local fire department, and still somehow managing to go to a community college where I am pursuing an Associates in Engineering Science degree before transferring to a university to get a BS degree in engineering, most likely as a mechanical engineer like my dad. At school, a talk about a number of different topics with one of the teachers, Mr. P, sparked my interest in RC again, as he was telling me of autonomous control vehicles and the things people had done with them. I planned to get a twin motor cargo plane, which I would let him use as a base, but hours of research on RCG caused me to change that to a quad. I loved the fact that with GPS they can go to specific waypoints, hold position, altitude, heading, etc on command, carry HD video cameras and first-person view (FPS) gear, allowing you to fly “from the cockpit”, have tons of fun, and do stuff no airplane can do.

As a result, I have made an order with HobbyKing (HK), to buy supplies to build my first quad. The list of parts that I ordered are below. I will not explain each part at this time, I will save that for when I first use that particular part.

First Quad - First Order

I think that does it for the first post. I’ve been at this for awhile and need to get back to sleep before work tonight.