Know How... 139 (Transcript)
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Today on Know How we will be bringing new life into old electronics. We are going to be doing something with this mysterious blob of stuff and finding the best motor for your quad.
Father Robert Ballecer: Welcome to Know How, it is the Twit show where we build, bend, break and upgrade. I’m Father Robert Ballecer.
Bryan Burnett: And I’m Bryan Burnett.
Fr. Robert: And this under the sheet here is… who knows? Probably a quad copter.
Bryan: Definitely something to do with Quad Copters right?
Fr. Robert: Because that is all we do on this show.
Bryan: It is probably something like a mobile platform from DJI.
Fr. Robert: We are going to ignore that for now because we have something more pressing to talk about.
Bryan: Very easily ignored right here.
Fr. Robert: Pay no attention to that being behind the curtain. Now Bryan, we are kind of in a drought huh?
Bryan: Yes, California has been suffering for the last few years.
Fr. Robert: It is funny because we have been having droughts on and off since I was a kid.
Bryan: This one seems to be sticking though.
Fr. Robert: This is sticking and it is kind of scary because when you drive the 152 it goes past this huge reservoir. And when I was a kid, there were years where the water would come up over the roadway and it would shut that thing down. That was how high the water was. Now I can barely see the water it is so far receded and so many hundreds of feet down that it goes nowhere near the roadway.
Bryan: It is very scary and it is not just drinking water that is affected. It is the recreational stuff that we like to do. Like going to Tahoe and enjoying the snow, which the snow is kind of where we get a lot of water over the summer.
Fr. Robert: That is the other part of it. Which is, we depend on the snowpack. No snowpack, means we don't get water throughout most of the year. And the snowpack doesn’t really exist anymore. Snowpack is kind of gone, but, skiing and resorts are still a multimillion dollar industry in California. So we thought we might want to talk about the technology that goes into making snow. We have all seen snow makers, but the more advanced ones are actually far more complicated than you might think they are.
Bryan: Yeah. I guess I just always imagined you get a refrigerator, you shave some ice and you just shoot it out.
Fr. Robert: That is what most people think.
Brian: You do it consistently so it doesn’t all melt.
Fr. Robert: But we know that is not true. Because real snow you get powder.
Bryan: Yes. It is much nicer to ski in power than hard pack ice. That is when you get hurt.
Fr. Robert: Anyone who has skied knows that skiing on ice is not fun. It is hard on your feet and you just don’t have that much control. Too fast sometimes, too slow other times. You actually do need snow and because it is more than just shopping up ice for more than just spring water in the air and hoping it freezes, well Alex, make it snow.
Bryan: Make it snow. Make it snow. Despite the best efforts by Disney, it still has not snowed.
Fr. Robert: Specifically I want to talk about this multi-step process that some of the bigger resorts are using with multimillion dollar pieces of machinery.
Bryan: This is their industry. They've got to figure out a way around us.
Fr. Robert: So the first part has to do with spring water. The it is not just like opening the tap and turning on the sprinkler. You divide your water into multiple planes. So you might have one plane going this way, one plane going this way and one plane going across it. The idea is to have the planes intersect with each other because when the planes intersects as the water is sprang out, it breaks them up into tiny little droplets. The more droplets you have, the more surface area you have which means the faster they will freeze. Because remember you need these things to turn into snow before they get the ground. Otherwise you…
Bryan: Are just icing the ground.
Fr. Robert: Huge icicles. But that is not it. That will give you part of the solution. The other solution is something that we figured out when we were trying to make rain. Have you ever heard of ceding clouds? They you is a process called nucleation which is, you need something that either the water droplet or the snowflake will form around. If you give it something it will actually glom and then it will form. Have you ever done the quick freezing beer?
Bryan: Where you put it in the freezer for a little while and then…
Fr. Robert: You tap it? That is super nucleation and all the liquid is really cold. It is cold enough to freeze but it doesn’t have anything to form around so it doesn’t. Then if you tap that you disturb it enough that you get bubbles and the bubbles become nucleus and then it just spreads.
Bryan: And that is what they can glom onto?
Fr. Robert: So you’ve got the spray, breaking up the planes, the nucleation so they have something to form around, and there we go. This is what it looks like. This actually shows you the last step which is pressurization and compression. Have you ever used a bottle of compressed air?
Fr. Robert: And you know that when you spray it, it gets cold. Well that is actually the law of thermodynamics. You are decreasing the pressure so therefore the heat is exothermically escaping. Well, what you do is you shoot high pressure air into these things and because there is such a pressure difference it actually drops the temperature. So these things can work up to 10° above the freezing point of water. When you think about it, it really is a science. And it is really different now than it was even when I was a kid. When I was a kid, though snow machines really made ice. But now, you’ve got an advanced snow machine and it feels like snow.
Bryan: Look at the powder. That little mound that they had built up? It looked like it had just snowed overnight.
Fr. Robert: So, yes we may be in a drought but we will still ski. Because of technology.
Bryan: Yeah. If only we had technology to make more water. Or do we?
Fr. Robert: Maybe that is what is under this curtain. Wait. Bryan, magic revealed. It’s a quad copter right? No? Wait for it. Boom. That’s right folks. We are getting into 3-D printing. This is not a quad copter, it is not as snow machine, it is not a rotisserie. We promised you that we would start getting into 3-D printing and this is actually a brand-new printer. This was just released yesterday. We got this a month in advance from the folks at XYZ. We first took a look of this at CES. This is the da Vinci Junior.
Bryan: Isn’t the appeal that this isn’t that expensive compared to others?
Fr. Robert: $349. So I am actually going to have the full review of this tomorrow on Before You Buy, so make sure you watch so that you get to see the whole rundown. Now the whole idea is they had a very successful product called the da Vinci. Which was nice, but it was a little expensive. Even now it is still $500. Back then it was 700 or $800. Which was affordable, for a 3-D printer but still…
Bryan: A little out of the range of your average hobbyist.
Fr. Robert: If you are just looking to play with 3-D printing you are probably not going to pay $500, $600 or $800 for it.
Bryan: That is a pretty big investment.
Fr. Robert: That $349? That is not bad actually. Very tempting. And the nice thing about this is the way that they built it. We are going to go over this in-depth in Before You Buy. But things like the removable head. One button and I can take the head off. That has been one of the biggest problems with the 3-D printers because they jam and then you have to disassemble the entire machine to get at it. With this I push one button, look this up and I literally turn the head over here and I push a button and I can slide this whole thing out.
Bryan: I like that. It is kind of modular.
Fr. Robert: It also does PLA only. There are two types of plastics that we use, called filament. So when we talk about filament we are talking about these spools of what looks like plastic. This is just plastic that has been rolled up. This is PLA which is actually an organic product, it is polymeric acid or something…
Bryan: So there is this one and then the other one which is?
Fr. Robert: ABS is a bit stronger because it is actually more flexible. PLA will tend to fracture before it really starts to bend. But PLA is an excellent material to start with. So once again this is a starter printer. This is what you would just kick off your 3-D printing career with.
Bryan: You have a few examples here that you built right? This is a little structure that you made for the quad copter. This feels really solid. This is a fairly complex little shape that you built and it is not very thick and you can kind of squeeze it but it feels solid.
Fr. Robert: And then you got everything from these, this is the rear mount for a tri-copter. I don’t even have this set at maximum resolution. Maximum resolution for this is .1 mm. That is the height of the layer that it can lay down. .1 mm is actually pretty good and this when will go to .5 if you really don’t need that much definition. The cool thing about a printer like this is you can manufacture these parts, and then bolt them together and you can do all this and change it within hours rather than days. Your design can really be a fast prototype. One of the other things that I like about this, is this bed. This is a non-heated bed. Right here the way that this works is this head just goes back and forth. This kind of motion is actually handled by the bed. So, I get all degrees of motion but I don’t have to worry about a multi-dimensional arm on top. This is actually a really good combination. One of the other features I really like about this, it is a stand out I think, is the ability to put your designs on a card. This is just a standard SD card. And I loaded up and now I can select from the front, I can build from card and I can selected design that I want to build and it does it completely isolated from the computer.
Bryan: That is cool. That makes it really easy to use then.
Fr. Robert: It is good for a workshop because you don’t want to have to have your computer hooked up to the 3-D printer for everything. You know, three or four hours or however long it takes to run it.
Bryan: That seems very well thought out.
Fr. Robert: It will print up to 5.9 x 5.9 x 5.9. So you get a cube of what you can build in here. What you will find in a lot of designs is you can break up the designs into the pieces that don’t get bolted together. This is one that I actually created. Because I started out with this. This I downloaded from the Internet. This was an FPV for a camera. So it actually has slots here so the camera will fit in the front. And then the battery will fit in here and you put the little transmitter in. So you have an FPV pod that is like a self-contained transmitter if you want to fly first-person view. You just stick it onto your quad copter and you are good to go. But I wanted something else since that didn't quite do what I wanted it to do. So I took that design and I used AutoCAD and I shortened it a little bit. I reduce the width and the height and I gave at this cool little channel so now the camera is actually just slotted in there. There is a little hole in the bottom for me to get the wire out of the camera and then the battery actually fits on the sled. Now all this wiring is messy right now but ultimately there is going to be another piece that snaps over the top and it will literally be a pod.
Bryan: See? That is what I love about the idea of 3-D printing. You can take something that someone else built and then modify it to your own needs. What is the speed like?
Fr. Robert: Okay. Speed will depend on resolution. Like I said, you can print as small as .1 mm. So that gives you really fine resolution. It gives you something like this. A very nice look to it. But that takes longer because it has to make more and more layers of really small layers. Well, versus something like this. This was printed very rough. I used .5 mm on this. And you can kind of see it. It is a little rough. But I didn’t need something that was pretty.
Bryan: You just needed it to be solid.
Fr. Robert: Exactly. So it depends on what you choose. Something like this, this pod right here took me about an hour and a half to print.
Bryan: That’s not bad. That is quicker than if you had to ship yourself a pod.
Fr. Robert: Like these. This takes like 10 minutes. For a set of four, because they are tiny. And then you’ve got things like this. Does this look familiar at all?
Bryan: That looks like one of the panels that would hold the camera.
Fr. Robert: Exactly. Wait a minute they actually have a template for this.
Bryan: That one looks a lot nicer.
Fr. Robert: It looks a lot nicer and it is a lot more sturdy. The other nice thing about this is once you dial it in, you can always print. You don’t have to order parts. I am always breaking things and I don’t have to worry about that anymore. I have a bag full of spares. You really are only limited by what you can imagine.
Bryan: One of the biggest pains though is that we got a 3-D printer may be a year ago and you always had to calibrate it. So I guess this one is all self-contained?
Fr. Robert: That is one of the other things I really like. There is no calibration on this whatsoever. You will never have to calibrate unless you break it. You physically jolt this thing. There are controls where you can set the offset so you can have the head lower. As long as you don’t mess with anything inside you are never going to have to calibrate it. The only thing you have to worry about is running out of filament and the head. Sometimes you will have to clean the head. Although, I've only had to do it once and I didn’t really have to do it I just wanted to see what the process was.
Bryan: And what is the process?
Fr. Robert: You let it heat up and then basically it is a fuzzy pipe cleaner that you put up into the head and you tear out any debris that might have stuck. Speaking of that, there is one thing about the XYZ printers that some people are not going to like.
Bryan: Yeah, you were telling me about that. This feels a lot like a regular ink printer.
Fr. Robert: I get what they are going with. So, I don’t want to open this because we are going to be talking about a lot of tips for the 3-D printing. One thing is when you get filament it is only stored in a bag, don’t open it unless you are going to use it. Filament will, by nature, absorb humidity. And if it absorbs humidity it actually affects the way that it prints. So you only want to break it out of it’s bad when you are about ready to print.
Bryan: So, say you hooked up a filament to your 3-D printer and you wait a few months to use it again, you have to replace your filament?
Fr. Robert: Not replace it, but if you are going to let it sit for a while…. oh look, this is another thing I really like this. It is one touch load. Loading and unloading a printer is normally a pain in the butt. It is not fun. This actually gives you a load that will heat up the head, hold back the filament and then you unload it. Then take it and put it in an airtight bad and it is good to store. But, each of these spools has an NFC card.
Bryan: I knew there was a catch.
Fr. Robert: People are going to cry foul. Because it sounds like you have just DRM’d the filament. You can by this filament cheaply on the inter-web. It is about $22 per 2 kilograms. The XYZ stuff is like 20-40% more. you might think you could just load more filament on the spool but unfortunately in the school right here and right here there is an NFC card system. So that when you put a spool on, it knows exactly what you have loaded and it knows the temperature that it should be setting the extruder for, it knows how many meters of filament you have left so it won’t start a job if you don’t have enough filament to complete it. But it also means once that counter gets to zero it won’t continue to print.
Bryan: Right. So…
Fr. Robert: It is a sad trombone.
Bryan: You did make some good points about why they would want to do this.
Fr. Robert: I don’t think this… I get what they are doing. In trying to make a beginner’s printer they are trying to cut down on things like people buying bad filament. And then suddenly you are breaking the head because there is a bunch of debris.
Bryan: When you start a project, the printer will know how much filament you have so that it can say that you need to add more if you are going to do this project.
Fr. Robert: I can go right here to information and it will tell me if I go to schools that what I started with. So I had 100 m to start and I have 26 m left. So it will tell me in the beginning because the programming that I used to create the STL files and turned them to EW files, it will say this will use approximately 6.2 m. So I know in advance if I should load up a new spool.
Bryan: I know. It just…
Fr. Robert: I will say this. I love the guys at XYZ and thank you very much for sending me this printer. I may have already hacked it. I know.
Bryan: We’ll see what we can do.
Fr. Robert: Will see what we can do about that.
Bryan: There are a lot of places to give filament.
Fr. Robert: This was just a quick demonstration. We wanted to show you what we are going to be using over the next couple of weeks. We are going to be bringing you a lot of 3-D printer projects. Next week we are actually going to show you the first print. Once you get one of these, and you will be able to get it now. Literally this was released less than 24 hours ago. You will be able to get one of these things and we will show you the entire process. And the advanced process. Everything from how do you load it up, how do you prepare the bed so you can print on it, how do you get the print off. And then the week after that we are actually going to show you how you can modify some of those STL files so you can customize your builds to what you want to see.
Bryan: We were talking about this earlier but I am going to have to start dusting off my old AutoCAD skills. To make the models.
Fr. Robert: This will do STL, it also does EW which is the data format for XYZ. And they include a program that will convert STL to EW. You don’t have to, but I like it because their software even though it is very rudimentary it will let you do things like flip and rescale. It is good for people to start thinking about how with 3-D printer has to print. It prints from the bottom up so if you’ve got a structure that is a single plane and then it breaks out, you’ve got to flip that out because the big breakout should be at the bottom. So you have to printed upside down.
Bryan: You have to start thinking in 3-D printer dimensions. And you have to plan your project and decide if you have to compartmentalize it.
Fr. Robert: So folks, the future in 3-D printing. Speaking of the future, let’s go ahead and take a moment to think the sponsor of this episode of Know How. Now Bryan, we are talking about tools here right? This is a tool. But you know what? This isn’t a fundamental tool. We talk about fundamental tools we talk about the tools you are going to need for pretty much every project that you do. Which is why we are always happy when we have iFixIt on the show. I fix it isn’t just tools. They make great tools that what iFixIt really is, is a place to go to find out how to fix things. They are not just a collection of drivers and sponsors. They are a one stop shop for all of your Know how manuals. If you want to figure out how to fix the red ring of death on an Xbox, you want to figure out how to fix clothes, you want to figure out how to fix that car that you’ve got.
Bryan: Or fix McDonalds toys. Or an old Game Boy?
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Bryan: One of these lives at my desk downstairs.
Fr. Robert: You know, I think six of them live at Burke’s desk.
Bryan: I don’t know if you would be able to put any of them back together. Keep your kits organized.
Fr. Robert: We might need an iFixit guide to fix the iFixit kits at Burke's desk.
Bryan: Maybe that should be one of our Know How segments.
Fr. Robert: Okay folks we did want to move on to something that is near and dear to our heart. That is taking electronics that you may already have an breathing some life back into them. Bryan, tell me what is in the box?
Bryan: What is in this sound box that I
Fr. Robert: That is a cranky hippo box.
Bryan: Well you know there was a few weeks back that Nintendo release their new DS. And I picked it up and I had a lot of fun playing it, there are a lot of great games on that platform. But, it didn’t scratch the nostalgia itch that I was hoping it would. And, low and behold I was rooting around in my closet and I found my old Game Boy.
Fr. Robert: You never forget your first Game Boy.
Bryan: It is kind of got that iconic look to it. I pulled out the old Game Boy.
Fr. Robert: It’s not the old original because all the old originals were plain Vanilla White. This is a colored one.
Bryan: This is a colored case, but that one was released in 1990. The very early ones in the first release were gray. And they had different buttons. You had one of the legit ones?
Fr. Robert: Seriously, my serial number is in the low thousands.
Bryan: Yeah, I believe it. You should bring it in sometime. Are you afraid that I will break it? Well anyway. The whole reason I busted this out is because I wanted to play some of the old games. I’m going to put Pokemon gold in now.
Fr. Robert: I had Pokemon gold but it was yellow.
Bryan: That is not Pokémon Gold then. That is yellow. You have the one where Pikachu follows you around. Anyway, this was first released in 1989 and I don’t think I picked it up until a few years later. But, one of the common things that happens with these poor guys is that they get these vertical lines.
Fr. Robert: Yes, I had that happen. Now, on mine I could hit it a couple of times and they would go away.
Bryan: So, the fun thing about working on some of these old electronics is that they are really easy to take apart as long as you have the right tools. The iFixit kit helped a lot because you have the tri-wing screws on the back. But once you are in there, all the components are spaced out. It is not like when I have done a tear-down on a new cell phone or something like that. This was meant to be taken apart by human hands and you can actually get in there and do some stuff. Now that I am almost 30 this thing is 20 something years old now too. There has been kind of a resurgence of people modding these and stuff. To fix the screen lines was super easy. And, to many of these have been tossed in the garbage because people think they are broken. When, in this next video that I made you can fix this within 10 minutes and it will be back to brand-new.
Fr. Robert: Well there you have it. Why don’t we see how hippo fixes the screen.
Bryan: So this little break of nostalgia is the original Game Boy. If you are not familiar with it, well you should be. This is the predecessor to all the mobile games that you enjoy now. It was released way back in July 1989. In the first day is sold over 40,000 units and we are going to breathe some new life into this old Game Boy. The nice thing about the game boy is that it is really easy to disassemble if you have the right tools. And they have tri-wing screws in the back of the Game Boy and as long as you have an iFixit case or a tri-wing screwdriver you will be able to get these out in a jiffy. There are six of them, for on the back and two behind the batteries. Once you’ve got those screws out you can flip the back of the Game Boy around. And you've got yourself a pretty easy access to the board, compared to modern electronics. This was built in the day that you could actually work on it. The problem with this game boy is that it had vertical lines missing on the screen. Which, some people might think was a death sentence for these little guys. Once the screen started to die. But it is really easy to fix. So, we will take out all the Philips screw heads that attach the front board to the front of the case. And just pop those out real quick and flip the front board around so you have access to the screen. What we are going to need to do now, is heat up our soldering iron and there is this little black piece of tape that runs along the front of the screen. That is where the soldering is attached to the LCD screen. And by just heating up your soldering iron and running it over that tape, which is very heat resistant so don’t worry too much, you can reflow the solder and have the LCD screen come back on. And retrieve those missing bars. So just take your time, I would recommend leaving the screen plugged in so you can watch what you are doing. Heat up your soldering iron, and leave it on the adage for no more than 3 to 5 seconds and watch as the LCD screen starts to come back to life. Just work your way up and down the length of the board and eventually if you take your time, you will have brought back all the little remnants of the LCD screen. And bringing this Game Boy back to working order. Which is awesome. And super easy. This took me about 15 minutes to complete. Also, there is a little black piece of rubber that you have to pull off to get access to where you are going to be putting the soldering iron. Make sure to hang onto that and put it back on and maybe put a little tape to hold it there or some glue. This is going to help protect those soldering joints that you just re-flowed by giving it a little cushion against the case. Not only did you have a little fun and learn a little bit about this old piece of tech, but you brought it back to life and definitely scratch that nostalgia itch that I had. Put everything back in the reverse order that you took it apart and put back on the front screen and you’ve got yourself a fully functioning piece of hardware from 1989, 25 years old. But we are not done. We are going to keep adding stuff to this Game Boy in later episodes to stick around.
Bryan: So now that you have done your screen fix with the vertical lines, I didn’t want to end there.
Fr. Robert: This is a good geek. Because you are just never happy to be done. As long as I am in here how else can I fix it?
Bryan: I wanted to add…
Fr. Robert: Wait. What?
Bryan: Yeah. There are these really easy, cheap kits that you can get to backlight this. These are nearly impossible to see unless you are in broad daylight.
Fr. Robert: I had an attachment with a little game port here that was like a LED light over the top.
Bryan: It was kind of janky.
Fr. Robert: Janky, but it worked. That backlight would be much better.
Bryan: So, it is not too difficult to do. The kit is pretty cheap and next week I will show you how to do that. A little bit of soldering, but if you have done any soldering where you did the project that I did about two episodes with the watch, this is not difficult at all.
Fr. Robert: As long as you are can it be poking around your Game Boy, why not make it better?
Bryan: So, I am having a lot of fun playing around with it.
Fr. Robert: Now, speaking of improving things. We know that we have gone a little quad copter crazy so we wanted to back off a little bit and give you a different kind of quad copter knowledge. Still very much quad copter technology, but we wanted to show you how we choose motors here on Know How. This is a Thrust Bench. It is a standard thrust bench measuring stand and all you need is the bench itself, you need some blocks to hold it down. The idea is you need a way to be able to measure how much the thrust a motor and prop will develop. The reason this is important is because that will vary depending on the motor you use, the prop, the angle of the prop, what type of battery you use, even the ESC’s. This is the scientific way to choose what parts you want in your quad copter.
Bryan: Would this be a good way of diagnosing if one of your motors is failing?
Fr. Robert: Actually yes. You can put all four of your motors on a bench and you can figure that this one is only half the output of the others. It is somehow damaged. Because when it is in the air, you can’t tell.
Bryan: It is a little hard to tell. You can tell that it is not flying well.
Fr. Robert: I would consider this an essential piece of technology. Something that you need in your toolkit if you are going to be doing some serious aircraft building. Not necessarily only quad copters because this will work for anything that you have to test the thrust on. I have been able to use this for airplanes that I have been flying around.
Bryan: This is cool. How much is this little kit?
Fr. Robert: Like $50. You can make it a lot cheaper. We are going to show you in a future episode how you can make an inexpensive one for about $10.
Bryan: It feels really solid.
Fr. Robert: This one is solid. I made a janky one and I wanted to see what a real one looks like. And now that I have a real one I am not going back to the janky one. Let’s talk a little bit about those questions about the motor and the prof. For example, we’ve got two different motors here. This is one of the Emax, the 2213’s that I recommended for Alien X. I kind of favor these. They are very durable, not that expensive, you can get them as low as $14 a pop if you buy them in for. Versus this. This is a Hobby King motor that I got on this thrust bench right now. It is technically rated the same but, we are going to see that it is not the same.
Bryan: When you look at the specifications on the page it says the same numbers and everything?
Fr. Robert: It says the same numbers. And that is the problem. Those numbers can be total lies. I can tell you right now the operation of this is not nearly as nice. You hear a little bit of a rattle. You don’t get that on this one. It is just the quality of the bearings.
Bryan: How much was this one?
Fr. Robert: Like $10. $10 versus $14. Pay the extra four dollars and get yourself something with quality. We want to look at the size of the motor, we want to look at the size of the prop and we want to look at the rating of the battery. How fast can it supply power through the ESC to the motor. Those will all affect how much thrust I can generate for any particular prop and motor combo. Remember we always talk about the combo because you can buy a really good motor and put a bad prop on it. You can get a great prop and put a bad motor on it and it is just not going to work right.
Bryan: Or by a great prop and a great motor and then buy a crummy ESC.
Fr. Robert: Exactly. Now let's start with shooting your motors. We have talked about this before but it is worth repeating. When you choose your motors, remember that you’ve typically got two numbers. There is a rating like 2213, and so a 2213 is a bigger and more powerful motor than a 2208 period that just refers to how many windings you have inside of the engine. I don’t want to give you an exact definition because it actually changes from manufacturer to manufacturer. But on a whole, the bigger that number the more power it will be. The more important number is the one next to it, like this one is a 2213, 1100 KV. Remember we know from KV that KV is the number of times that this thing will spin, the number of revolutions per volt that I give it. So this is an 1100 KV motor, which means if I give it 10 V it is going to spin 11,000 times a minute. That is my rotation. Now we also remember from way back when, motors that spin faster typically offer you less torque. Motors that spin more slowly offer you more torque.
Bryan: Which is better for bigger props.
Fr. Robert: Right. Exactly. So, if I have a motor that spins at 2300 KB but it is rated 2213, it means that it needs to use a smaller prop. It is just going to spin it more quickly. Something like this which is an 1100 KV. There are motors since then at 600 or 680 KV. Those are designed for those huge props. Which, theoretically, is more efficient. When I spin my bigger prop more slowly I will get more flight time out of it. Because I am not spinning it so fast.
Bryan: But that is less of a performance or aerobatic squad.
Fr. Robert: When I was building my 250 class I used the 2300 KV motors because I want that motor to be able to spin up-and-down really fast because that is what gives me all the crazy acrobatics. But, if I am shooting I want to be able to use a big profit because it is going to spin more slowly, less vibrations and it is going to be more stable and give me more flight time. Because I am not going for acrobatics I am going for film quality and time in the air. Now that we know that, that is choosing our motors. Next is choosing the props. We kind of led into this and we talked about this before. This is a nylon prop. You can see that. Boing, boing. This, is a carbon fiber prop. There is no boing in this. This is stiff. Now, people will debate this. You have to balance all your props it doesn’t matter if it is nylon or carbon fiber. Carbon fiber props tend to be lighter. Lighter props will spin up and down more quickly. And spinning up and down more quickly gives you more acrobatics.
Bryan: Would it then make it more efficient? Because there is less work for the motor to spin up and down?
Fr. Robert: Yeah. It does. But, some people like the nylon because they will flex and to a certain extent props that flex will take some of the vibrations that would otherwise be transferred into the frame. It doesn’t always work that way. In fact I have found I just would rather have carbon fiber all the time. Unless it is a trainer craft and I am worried about it because if you hit something with carbon fiber props it will cut you. Nylon will not cut me. Carbon fiber will first snap off and then it will leave a jagged edge will cut to my skin. But, if you notice this is a ten inch prop and this is an 8 inch prop. You can have multiple types of 10 inch props that the angle is slightly different. This is a more aggressive prop, it has a higher angle which means it is going to pull forward more. But it also means that it will pull more power from the motor. Sometimes you just want a slow fly because a slow flight prop will give you that nice smooth, long-lasting flight.
Bryan: The angle of the pitch.
Fr. Robert: So increasing the size of the product increases the amount of power that it will draw. But it also means you can run the motor more slowly. The practical use on the Alien 450’s that we just built, those motors can be used for both 3S and 4S batteries. That is the 11.1 V with a 14.8 V battery. If you are going to use it with the 14.8 V battery, you would go from these 10 inch props down to an 8 inch prop. Because if you try to put a 10 inch prop on a motor that is supplied by a 14.8 volt battery, it will burn out the motor.
Bryan: Because it is just so much on the motor.
Fr. Robert: It is just demanding too much wattage from the motor. It will burn it out. So, I can get a big prop spinning slowly or I can get a small prop spinning very quickly and the nice thing about that is I can change depending on how I want to fly. If I want to get daring, like my quad flying over the water, I used 8 inch props because if I wanted to punch out if I was getting too close, I didn’t want to wait for my props. I wanted to throttle it up and get it out of there. But if I wanted to do a shot located at the beach in Hawaii with that super smooth shot, those are 10 inch props because I knew I was just going to pass slowly. And I didn’t need a whole lot of performance.
Bryan: And so, now testing these on the bench?
Fr. Robert: So, this is a very basic thrust tester. All it’s got is a way to mount the motor, a scale which is right here will allow me to figure out how hard this thing is pulling. I am using a 3S battery so this is 11.1 V. So what I do is I've got a servo tester here and I am going to go ahead and slowly….
Bryan: Padre! There is dust everywhere. Did you keep track of the numbers?
Fr. Robert: I did. This went up to 809 grams. So at it’s maximum this motor with this prop and that battery will pull 809 grams of thrust. I’ve got four of them so I know I can get 3.2 kg worth of thrust out of my motors. Which is decent payload especially since the frame is only going to be 300 g. It is a good power to weight ratio. Now, let’s go ahead and take a look add a motor that has a same rating as this. It is our wonderful little Emax, 2213.
Bryan: You changed that motor quick.
Fr. Robert: What we have done is gone ahead and replace this Hobby King multi-star motor, which has the same rating as this, with the Emax 2213. Now, we should note that we are using the ESC. this is not my personal favorite ESC. This probably robs you of maybe 5% of thrust. But we want to use it as a baseline.
Bryan: That way we can compare the two motors.
Fr. Robert: Precisely. I’ve got the set up rotating the proper weight. One thing you should know, if you ever have a motor that is spinning the wrong way all you have to do is reverse to the leads. Just any too. Just flop them around and it will spin the right way. So now, we've got the same set up. This is actually the same battery. We are at a disadvantage because we have already been draining this battery testing the other motor. What I have at home is a bigger battery that can withstand drains much better. We know the other one, at its max was able to pull 809 g of thrust. This is the exact same rating, the exact same speed with the exact same prop. Let’s see if it does any better.
Bryan: Stand back. It’s all over the place.
Fr. Robert: At its peak this actually pulled 830 g of thrust. And leveled off around 790. Versus the other motor which pulled at its peak 809 g of thrust and then it leveled off somewhere around 760 or 770. You are going to see that because whenever you see that pushback it actually means the battery can’t supply enough power to the motor. Which we will address, because next week I am actually going to show you my super advanced build. This is a decent thrust tester but it only gives you one metric. It gives you how much thrust am I generating. The better kind of thrust tester will also show you how much thrust are you generating, how much power are you using, how much wattage and where it is being used in the curve. And it will also tell you whether or not you are starting to exceed the power limits of any part of your system.
Bryan: That does sound like a lot more information.
Fr. Robert: And believe it or not, you can do it with just $20 in parts. Not bad at all. So, I gotta tell you. I like flying quad copters but there is part of that is really squeezed to build stuff and this is a big old building toy.
Bryan: That is how I feel about the Game Boy and that is why I liked playing with Legos. It was putting it together that was fun. And then you get to have fun when it is built, but it wasn’t the main part.
Fr. Robert: Now folks we know that this was a lot of material for you to handle. And which is why we are going to give you detailed show notes. Now typically this is where we go. This is where we would drop off, after telling you they could find our show notes where?
Bryan: At twit.tv/KH. And not just show notes but all of our previous episodes and ways to subscribe and download the episodes.
Fr. Robert: Speaking of ways to download the episodes, there is no better way than participating in the Google plus group. That is really the best way. Seriously. 8300 folks, a very active group, there is always someone there that is posting. If you have a question or if you have an answer. If you are one of these people who want to contribute your knowledge to the group of DIYers and makers it is a great place to join. Just go to Google plus and look for the Know-How group. Join in and ask a question. And more likely than not if you have a project that you want to post we will use it on the show.
Bryan: And my favorite part? Is seeing other people’s projects. There have been plenty of crash videos from the quad copters. There have been plenty of mods for some of the other things that we have done. There is a lot of cool stuff to check out in there.
Fr. Robert: And it is also a really good place for us to get ideas for future episodes. People wanted to see Raspberry Pi, so last week we did Raspberry Pi OSMC. And we are going to keep doing that. So suggest, ask, and we will answer. Don’t forget that you can also find us on the other social media, specifically twitter. Just go to , that is me.
Bryan: And then me. @cranky_hippo.
Fr. Robert: One last thing before we go we do this thing every once in a while we call it a parting shot. There is actually a special one. Something that… No, Alex. Bad Alex.
Bryan: Come on.
Alex: We’re a little early, we’ve got time.
Fr. Robert: I need to do this thing. This thing, this Solar Dynamics Observatory is a space project that I have just been peeking out over. And I have been containing my geek. Have you heard me talk about SDO?
Fr. Robert: Exactly. I keep it to myself.
Bryan: Typically you have a very hard time containing your excitement about things. So I am surprised I haven’t heard anything about this.
Fr. Robert: But this thing is beautiful. It was launched five years ago and it has been orbiting the sun. It has been taking high resolution images and videos once every second and it has been absolutely gorgeous. I don’t want to talk anymore, Alex just play this with the music. The amazing thing about that is you are actually seeing the electromagnetic bands. That is the plasma that is traveling along the electromagnetic bands that form on the sun. So it gives you visual representation to something you wouldn’t otherwise be able to see. It is beautiful.
Bryan: That is so cool. And just the immense amount of gravity for something that huge.
Fr. Robert: In the amount of power that you need to blow out that much material from a giant ball of plasma. Awwww. I’ve watched this video maybe a hundred times in the last month.
Bryan: I want an apartment next to the sun.
Fr. Robert: You need a really good air conditioner and sunscreen. you got burnt standing on a Segway. What you are seeing is the reason why sunspots happen and it is because there are regular magnetic lines that flow through the sou just like through the earth, but the surface is so turbulent and the inner workings of the sun are so turbulent that the lines actually start to wobble. And then they cross and when they cross you get a short-circuit and it causes that expulsion of material in the sun.
Bryan: That is crazy. Now if you wanted to stop the reaction of the sun…
Fr. Robert: All you need is iron because iron actually kills fusion reactions. The sun is based around fusing lighter elements into heavier elements but when he gets to iron, it stops. So you have all this pressure that just keeps pushing and pushing on the iron but it won’t use. And the sun, actually any star, is a balance between wanting to explode from the reaction and the immense pressure is rapidly pulling back in. So if you start to compress iron, which will not fuse, therefore it will not create a plume of energy it no longer has that thing pulling it back in and the star just blows itself apart.
Bryan: I could watch this all day.
Fr. Robert: I know, right? Okay we gotta go. I’m sorry I was just… awwww. That is it. I’m Father Robert Ballecer.
Bryan: And I’m Bryan Burnett.
Fr. Robert: And now that you know how…