Recent ArticlesScale Swappable P51 - Design, Build, Fly
SketchUp for RC Aircraft Design Tutorial #7
SketchUp for RC Aircraft Design Tutorial #6
I have been flying a tricopter for a little bit now and decided it was time to move up in the world and get a quadcopter. I decided to go with a 450mm frame, and I found a nice cheap one from HobbyKing. It is the Q450 Glass fiber quad with nylon arms. Has some good reviews for being a solid frame so I went for it, and at only $11, I should have got 2 of them.
Being my first quad I was not completely sure on what to go with for electronics, so I spend a significant amount of time reviewing motors, and trying to figure out how much power I would need. In the end I feel it is a pretty good setup. My end goal is to do fpv with it, so I wanted to make sure I would have enough power, but was also trying to aim for a little bit of efficiency to hopefully get good flight times.
Here is a list of all the parts I ordered even with express shipping it was only about $150.
If you do this build you may want to consider using a different type of motor! I have been using the setup for a couple weeks and have found a couple issues. First off it is hard to find counter rotating props in a good range for the motor I used. The motors have been getting warm, which did not concern me too much, however I just recently installed a KK2.0 and now the motors seem to be getting hot, also flight time is very short, like 6-7 min. If you would like longer flight time and an easier time with props go with a lower wattage motor, and a lower kv rating that can handle a wider range of props. I am considering buying new motors, or trying some 7x3.5 three bladed props, other wise I was considering getting new motors.
I used some wire, bullet connectors, heat shrink,and zip ties that I already had during the build.
First thing to do is assemble the frame. (always use lock-tight or some other brand of thread locker on the screws while for the whole build, this will save you later) This frame is a piece of cake to assemble and comes with everything you need to assemble it, including a wench to tighten down the screws. Note: if you use the included wrench be careful, it will strip easily and can damage your screws as well. Took me about 10 minutes to put the frame together. I could have had it together in 5, but a few of the holes on the glass fiber plates did not line up properly. I simply used a drill and a drill bit to drill out or key hole the hole till the screw could go in straight. I think I only had to do this with 2 top holes and 1 bottom. I was extremely impressed with how solid this frame felt. It was very rigid with almost no flex.
Next I mounted all the motors, pretty simple and the holes all lined up good. Again make sure you are using some kind of thread lock on your screws.
Next thing to do was to get the ESCs all st up and in place. I do not like the wires that come with the plus esc, they just seems kinda cheap. Plus they are never the right length. So I stripped off all the heat shrink, removed the battery leads and the motor leads. I then replaced them with a different wire and of the proper lengths. Once the wires were on, I used 25mm heat shrink I had left over from my tricopter build to recover the ESCs. I added my female bullet connectors to the battery leads, the process is very similar to what RCexplorer does with the V2.5 tricopter build (Tricopter V2.5 build log). I ran the battery leads down through the frame to get them closer to where the battery will be placed and I also thought this would help keep it looking neat. I used simple zip ties to strap the ESCs down and in the end I came to a couple discoveries: first that I did get the wires out of the way but now they were in the way of the battery, also it was a pain in the butt to solder 4 wires to my deans plug, and finally: I should have bought the other version of the Q450 frame. I was browsing HK website a few days after I bought this frame and noticed there was another identical frame with integrated PCB. In other words the power leads have a place on the bottom plate of the quad frame designed to solder you battery and ESC leads to. This would have cleared up a bunch of wires on my frame, and despite it would have required more soldering, one wire at a time is easier than 4 in a bunch. Q450 w/integrated PCB This frame costs $7 more, but still at about $18 it is still a steal.
Next programmed and mounted my control board. Programming the control board is a bit of a pain and takes some time to get set up. I am not going to go into any details on that, since Flight test has a video on it, and you could write a whole article just on programming the board. I would suggest possibly buying the newest KK board offered from HK, KK2.0 control board with lcd screen This board looks awesome and comes already programmed. It also has some sweet features like, auto-leveling function, 3 axis gyro, 3 axis accelerometer, etc... Click the link and you can read all about it. The board is twice the price as the one I have for this build, however based upon some of the videos on youtube, its sweet board and still a great price. I do have one on order to add to my quad once it gets here. Dhdsracer has a great video under multi-rotors for basic tuning of the KK2.0 board. I think it will be very useful when I get mine. As for mounting the kk-board, I still do not really like to use screws to mount it down. So resorting back to building my tricopter, I used double sided tape folded over several times and then cut into small blocks to hold the KK board. It seems to be a good setup on the tricopter and the thick foam like tape does a great job at reducing vibrations. KK board do not function well with vibrations.
Once the board is mounted and facing in the right direction, go a head and plug in all your wires. make sure you match up the correct leads for elevator, throttle aileron, rudder, and you have the ESCs plugged into the proper spot based upon the programming of your board.
Side note: something I like to do with my KK-board. I am pretty rough on my stuff, and kept noticing with my tricopter that I was constantly bending the gyro on the board that sticks up vertical off the board. A very simple and effective solution I have found to solve this issue other than making a cover, is to use a little epoxy around the base of that gyro. It has the risk of transferring vibrations through the board to the gyro, but if you balance your props and remove as much vibration as possible it should not be an issue. Plus it is super strong, I slammed my tricopter into the ceiling of an archway and bend almost all my pins but that vertical part on the board held solid as a rock! Here is a link to that video if you want to check it out (Crashing Tricopter) and a couple pictures of the board.
If you want to use epoxy on the board to make it more durable all you have to do is mix up a little epoxy (fast curing works better and is easier to control) with a q-tip. Use the q-tip to add very small amounts of epoxy to fill the gap under the board and around the pins mounting it to the board. Try not to get epoxy on anything else. Do not cover any of the gyros, and avoid covering any of the other electrical components on the board. The one pictured above I did a sloppy job and used 30 min epoxy which gave it too much set time allowing it to flow down on the board. I do not think this has had any effect on the board, but I feel it could be a bad idea to needlessly cover parts that do not need it. Below is a pic of the job I did for my quad board. You can tell is it a lot nicer looking, and did not run over anything else on the board.
Once the board is mounted and all ready to go, it is time to plug it in and test everything out. Flitetest does a great job at demonstrating how to set up and check you control surfaces to make sure everything is spinning the right direction and compensating properly. I can not emphasize enough how important it is to remove or refrain from having the props mounted while doing this step. Flight test show how to use tape in one of their videos to set it up and it is a safe way to do it. Quad controller set up
I made the mistake of leaving the props on to test out a a board after installing new firmware. The copter flew off my table and went flipping across the room from very little control input, thank goodness it did not go towards my face, however my hand did suffer a few lashings which you can see below.
3 Slices on my pinky, small one on the ring finger, nice deep on on the knuckle, and a small one the knuckle nearest the bottom of the pic. If this had been my face, I am sure the damage would have been worse, and this was just from being clipped by one prop. A quad has 4 props which potentially could cause 4 times the damage.
Moving onward. Once all the motors are spinning the right direction and gyros compensating properly, it is finally time to mount your propellers. The propeller i bought were way out of balance, and needed some serious work. One of the biggest success factors of multi-rotors depends on how well you balance your props. You may think you have your props balanced, but chances are you should go back and do it again. I balance my props twice before mounting them. And it may sound strange but I actually balanced them one day, and then balanced them again the next day. Each time I balanced I leave a little check mark on the prop to keep track. A few things you need to consider, of you crash, chip, or scrape a propeller on something, chances are it is now out of balance and you should consider balancing it again. It is summer its hot, people get fans out they have their AC running, moving air can make it difficult to balance your props. A good prop balancer has very little resistance, it will not take much air movement to get a prop to spin on the balancer. So keep that in mind while balancing. And make sure you get a good prop balancer. I use a top flite precision magnetic balancer and it seems to work perfectly.
Once your props are balanced and mounted it is time to fly for the first time, and adjust your gains to get the best possible flight characteristics. There are a lot of tutorials and information on that out there, so I am not going to go into much detail on that.
If you are going to fly FPV you will need a good camera mount and something that dampens any possible vibrations.For good quality images, you need to keep vibrations away from the camera. I have a little setup that seems to be very effective for a GoPro. It is similar to the one RCExplorer uses on the tricopter, only I use two different types of tubing inside each-other, which seems to work very well for what I am looking for. And it is super cheap and easy to build. I use almost the same template as RCexplorer for his tricopter mount, except I make my mounts our of bass wood. Its really cheap, rigid and seems to warp less than plywood does...maybe i had cheap plywood. The wood is about 1.75 inches wide, and 3/16s inches thick, and it is about 9 inches long. Weird dimensions but it seems to work well for this application.
The bigger tubing (outer tubing) is 3/8ths inch latex tubing, (I would not recommend using it ifyou have a latex allergy) and the smaller tubing (inner tubing) is silicone airline tubing for a fish tank, I got it at the store for a couple bucks. The Latex tubing was a bit more expensive and I think I got it from Home Depot and it was like $11 bucks, but I use it for other various applications. I figured out where I wanted the camera/camera mount to sit and made some marks on the board where there were places I could zip tie it to the quad. Drew straight lines across the board using a square, and then on each side made a little notch with an hobby knife for the zip ties to sit in. RcExplorer shows how to do this in the tricopter v2.5 build.
The small tube fits almost perfectly inside the bigger tube, it has a little bit of play, but it seems to help. Cut two pieces of each tubing to the same width as the board, and place the smaller tube in the bigger tube.
Then place 2 zip ties through the smaller tube, you want the zip ties facing opposite direction. One will strap the tube to the camera mount the other will strap the mount to the quad.
This is the same setup I use on my tricopter and if you watched my tricopter crash video linked earlier in the article you can see it produces fairly smooth video.
Alright time to test fly! When test flying make sure there is no one too close, and you have open space to ABORT if anything goes wrong. I am using xcopter 4.7 firmware, I have the pgain and yaw set to 50% and the I-gain set to 0% for starters. I also had a pretty windy day to test it, which is not the best testing conditions, but I had to see if I could get it in the air. My tricopter seemed to be really twitchy when I first got it in the air, and did not have dual rates or expos tuned in. I programmed in dual rates and expo before running tests. I had 85% on elevator and aileron, and 100% on rudder. Expo set and +25% across the board. Seemed like a good place to start. Here is a link to the video: Hover/Flight testing
It seemed really stable and lifted off way better than my tricopter does. The tricopter always seemed to need a little stick input to get it to lift off correctly. The quad got right off the ground no problem. The green 8x4.5 props seem to have good power and work well, however the motors and ESC seemed to be getting a little warm after spending about 5 minutes in the air with it trying to trim it in. I am not sure if it is the props or the fact that it was like 100 degrees out when I was testing it. Everything was just warm nothing was hot, but I may have to go to a little bit shorter prop. Hovering was acheived at about 1/4 to 1/3 throttle, so I feel a shorter prop should not affect it to much.
I decided to get my GoPro and video equipment mounted to test it out. The biggest issue I was having with this frame was there is about ZERO room to put anything other than the base electronics for the quad. So adding my video equipment was a pain. I did manage, but I am not sure as to how it is going to work. I have the Vtx fairly close to the receiver, and had to mount it to the back of the GoPro. Plugged it in and everything seems to work well and I get a good clear image.
Time to test the camera mount and make sure the added weight is not causing my motors/ESCs to heat up more than they already were. I did nto fly fpv but did a quick flight and turned the camera on, so here is that video and you can also see the results I am getting with the camera mount. Camera mount/weight testing
Even with the extra weight the frame is holding solid as a rock. This frame is awesome!! I am very impressed, not sure how it will take a crash, I would think really well. I hopefully wont find that out any time soon though.
The last thing to do is Fly full out FPV and make any final adjustments to tuning based upon your flying style. I have not had a chance to fly FPV yet, but check back soon because Ill be putting one up as soon as I have it. Let me know what you all think!! Comment Below.