Woodworking programmer

dredding · 1 day

I like making things. It just so happens they pay me to make things out of 0's and 1's. Besides, woodworking is relaxing for me when I do things I want to do and there isn't any deadlines or anyone telling me how to do something.

siggipow · 15 days

Heat capacity, C, like all other thermodynamic properties, is a material property that can be defined as a function of two other thermodynamic properties (temperature, pressure, enthalpy, entropy, volume, density, etc.). In most cases, C is defined as being a function of pressure and volume. When you make the assumption of a thermally perfect material, you're assuming the dependence of C on either pressure or volume is neglected, hence Cp and Cv. Therefore, you can define Cp or Cv as functions of only one other thermodynamic property instead of needing two (except pressure for Cp and volume for Cv). Typically, Cp and Cv are defined as functions of just temperature.

So, when you're using Cp or Cv in your calculations, the pressure or the volume of the system can change, but it will not affect the value of Cp or Cv. (e.g. d(CpT)/dP = CpdT/dP)

its_curt · 2 months

I use a laser cutter to cut 1/8" balsa ribs for an RC aircraft wings. It cuts like a hot knife through butter with very high precision. The particular one I have has a hard time cutting through 3/16" ply though (I think it has a lot to do with the glue). Before I had access to this laser cutter, I used a CNC machine.

It all depends on the particular laser cutter you're using, how thick the medium is, and what it's mad of. To cut, the laser is generated, sent via mirrors to the moving head, and finally focused to where it's strong enough to cut on your flat piece of wood/plastic/etc. The laser cuts best at the distance at which the laser is focused to the smallest point. If your medium is too thick, the laser will not be focused well enough at the top and bottom (assuming you're focusing to the middle of the depth of the medium). It will either not cut all the way through (if the laser is not powerful enough) and/or you'll get an hourglass-like edge which will only be correctly cut at the focus depth.

I didn't mean to scare you away from laser cutters, but it comes down to what you're cutting and the capabilities of the particular laser cutter. For me, it's exactly the tool I need. I suggest you speak to the owner/manufacture of the laser cutter and determine whether it will work for your project. Some laser cutters will allow you to etch and/or burn designs into face of the wood.

As for a CNC mill, the depth of your cut will not matter (for wood) and you will not get the slight charring you'd get from a laser cutter. The precision is roughly the same as a laser cutter, only you would be guaranteed a straight edge (or which ever end-mill you're using). The downside is it takes much more prep work to run and therefore will cost you more if you're having someone do it for you: you need to determine how it will be clamped to the table throughout the entire cutting process (not always trivial). It may even take a couple iterations of setup and cutting to do the entire project. Depending on how soft your wood is, the edges may get ripped along the grain (it does a little for balsa). Lastly, your inner corners can only be cut with a minimum radius of the end-mill.

All in all, the precision with any of these two machines is much greater than anything you could want to make with wood. Each have their advantages and limitations. I don't know what it costs for someone to do these things for you, but I can only guess the CNC machine will be more expensive. Good luck!

bitch_im_a_lion · 3 months

Eat all the things. Unless you have allergies to coconut; in that case, you better pick the right one.

moontanned · 4 months

I believe there's a copyright on that.

Yazzz · 4 months

If your guitar is in tune on the open strings/lower frets, but not on the higher frets (12th-15th), the intonation on your guitar might be off. You'll have to have someone fix that for you.

Although this probably isn't your problem because you're having this issue on the 3rd fret and not the 12th, I thought I'd note it here because it's relevant.

BdotDS · 4 months

Another thing to consider is Fortran (and to an extent, MATLAB) is not object-oriented. In the long run, it may be easier to use a general class instead of having to write a specific function every time you want to do something.

ra_grand · 5 months

It was in the main() after goToCornerStore().

ra_grand · 5 months

I could have rewritten everything, but who does that? I just stole what I needed from 99X; it doesn't need to be efficient.

kil-art · 5 months

I'm a master's student in aerospace engineering. I can answer some of your questions, but not in too much detail. I'm not an expert by any means. I'll try to answer all of the questions you've asked, but out of order to make it flow a little better.

The tail-rotor is there to cancel out the force due to accelerating the blades and force due to drag on the main rotors. Coaxial rotors like on the Ka-50 accomplish the same thing by spinning in the opposite directions. The problem with these is the rotors have to be very short and stiff to prevent them from bending into each other. More flexible blades damp stimuli and put less stress on the crew and the rest of the structure. Shorter blades means they have to spin them faster to get the same amount of lift because there's a smaller wing area, which also puts more stress on the rest of the vehicle. You are correct about the tips of the blades reaching Mach 1. The blades are made with a subsonic airfoils and would stall if a shock wave were formed (I forget the details about this phenomena so I'll leave it at that). As for the Chinook, the blades also spin the in opposite direction. They can carry very heavy loads but they are very difficult to maneuver. They have difficulty doing some maneuvers in some directions because of the gyroscopic effects of the rotors.

There has been a couple major break-throughs in the last couple years. The biggest problem with rotary-wing aircraft is that they are slow compared to fixed wing aircraft. For most helicopters, the only way to move forward is to put some of the resulting force of the rotors in the forward direction by leaning in that direction. As the helicopter increases speed, it needs to lean forward more. This messes with the angle of attack of the rotors. If you speed up too much and lean too far forward, you get what's called retreating blade stall. This happens when the blade moving backwards gets too high of an angle of attack and fails to create enough lift. The helicopter then stalls on one side and spirals out of control. This, of course, limits the top speed of the vehicle (which decreases as the altitude increases and the temperature increases). To prevent this, you need to design the helicopter so that it's not tilting forward as much. There have been a couple attempts to remedy this by getting a forward propulsion from another source. I couldn't tell you which one is best, they each have their pros and cons. Some blend with fixed-wing techniques like the Eurocopter X3. One really cool design is the Piasecki X-49 which points its tail rotor straight backwards and vectors just enough air sideways to balance the main rotor.

As for the downstream air affecting the aerodynamics, I'm not sure. I do know the turbulent air in ground effect is a huge area of research. The helicopter is affected a lot by this, which is why landing is the most difficult part. Not to mention the dust that gets kicked up, sometimes making it difficult to see anything at all in sand and snow. You have to worry about the exhaust from the engine getting sent around back into the intake, which can drastically reduce the power. Just above the ground is the last place you want to lose your engine.

Lastly, here's a video of a helicopter doing an autorotation landing with no power.

ra_grand · 5 months

function buyFood() {
    buy.bread(1);
    if (eggs > 0) {
       buy.bread(12);
    } 
}

anitasanger · 5 months

When MTV does anything but play music, you know things are B A D.

Firerhea · 5 months

You came in that thing? You're braver than I thought.

bigpapasmurf6 · 5 months

Niagara Climbing Center.

no1stunna · 5 months

They do cost a ton. If you think about the cost of something that you would think as a respectable investment to you personally (i.e. $10,000 for a car), know that to a company, they may feel the same way about an investment 2 to 3 orders of magnitude higher ($1,000,000 to $10,000,000) for a single to several machines.

Also, there are companies that do specialized in making specific machines. If they're clever, they design a machine to be very robust. Meaning, at its base, it's the same machine, but maybe has an attachment to specialize it even more.

no1stunna · 5 months

It's usually a mechanical engineer who designs the actual machine, or an engineer in the field of what it will be making. Very complex processes are researched by engineers with a master's degree or a PhD at a university or private research company. Once they show that whatever it is they're making can be profitable, they usually sell the technology to a company who has its engineers make it faster and cheaper.

As far as the assembly line, plant layout, and human-machine interfaces, it's usually an industrial engineer. If it's a chemical plant with reaction chambers, pressure tanks, and chemical flow, it's usually a chemical engineer. Of course, being one type of engineer doesn't stop you from knowing all the things.

MrBaz · 6 months

I start counting at zero. What's the problem here?

jjacques · 6 months

Definitely not.

jjacques · 6 months

I can be clean, but no way am I clean enough.

prtyfly4awytguy9 · 6 months

The pizza boy would probably get full after the first 5%. He wouldn't want to eat 95%.

no_front_teeth · 6 months

I drive past those coordinates almost once a week.

interestedinscience · 7 months

Would there be Lagrangian Points where light and mass could get stuck, however unlikely?

kai-ol · 7 months

Fun fact: Mg would mean Mega-gram, 1000000 grams, or 1000 kg.

candry · 7 months

I went there today for the first time and the same thing happened to me. I thought I had forgotten how to drink correctly. I was wearing a suit, but luckily my hand was in the way and caught the rogue drop.

EIros

TROPHY CASE

EIros

TROPHY CASE

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