In one sentence, describe what the following article is about: You will want to do this very slowly, as applying too much throttle right away can cause your copter to tilt, and fall over, which will cause damage. This initial surge of power is called a spool. When you spool properly, the blades will turn, and you should start to feel some vibrations. Immediately stop spooling when the copter gets lift and wants to come off the ground. This is done by simply lowering the torque slowly. With your helicopter on, this is the perfect time to use your eyes. See if your helicopter is shifting left or right when it spools. Listen with your ears to the engine. It should be making a consistent running sound, not a sporadic pumping sound. When your helicopter is on the ground, do not add any cyclic trim. This will cause your swashplate to tilt in the direction of your command, and send your copter off against the ground. Each of your rotor blades sits at an angle. Most helicopters will hover between 4.5 and 5.5 degrees of positive pitch. If the angles of each blade are off from another, one blade will lift higher and cause your helicopter to crash. In order to adjust this so that the blades have even angles, you should first mark each rotor blade's tip with a different colored piece of tape. Next, turn your helicopter on, just so that it gets an inch or two of lift. Put on your safety goggles, and make sure your partner (if you have one) is wearing goggles as well. Bend down so that you are level with the running copter. You will want to be at least 10-20 feet away from the copter when you do this. If the blade tracking is set correctly, both colors of tape will overlap with one another. However, if the tracking is off, you will be able to distinguish which color is higher and which is lower. If the blades are off kilter, stop the helicopter and turn it off. You will want to reduce the height of the higher blade, while also increasing the height of the lower blade. Adjust the ball link that shifts the pitch per helicopter instructions (ball links vary widely among types and brands of RC helicopters). Once this is done, turn your helicopter back on, get back on the ground, and see if the colors overlap. This may take two or three rounds before you get the height of the blades even. Place your helicopter in the middle of the field over which you will fly it. If there is any wind, make sure that the front of the copter is facing towards it. Start your helicopter as you are standing about 10 feet behind it (always wear your goggles). Turn on your throttle until your helicopter is light on its skids. If it begins to drift, simply lower the throttle back down. With a fly bared machine, depending on the way your helicopter begins to drift. For example, if you have clockwise spinning rotor blades, the helicopter will almost necessarily lean left. Apply some right cyclic trim with your fly bared machine. To access controls to your fly barred machine, you should either retrieve your independent controller, or the channel accessed through the swashplate. Start your helicopter up again, and allow it to hover/skid on the starting position (reference point). Once the helicopter is stabilized at the reference point, you can slowly increase the throttle forward. Your helicopter should move forwards about 10 feet, before you slowly decrease the forward command. Stabilize the helicopter at this position, as the helicopter skids gently against the ground. Then turn your throttle to the backwards position. Bring your helicopter back to the initial reference point. Do the same thing as before, except move your throttle to the left and/or right, thereby moving your helicopter to the left and/or right of the reference point. Each time, move your helicopter 10 feet, stabilize, then turn your throttle back in the opposite direction to bring the copter back to the initial reference point. As you move your helicopter, it should stay fairly close to the ground. The nose of your copter should always be facing forwards and towards the wind. Turn your helicopter on, and stabilize it over the initial reference point. Your copter should be bouncing on its skids as you increase the throttle (collective) power slowly. First, increase the collective until your helicopter is about 3 inches above the ground. After you get it to this point, begin lowering the copter back down to the ground slowly by decreasing the collective. Repeat this step through a series of increments. Start by going 3 inches in the air. Once you feel comfortable with this, go 6 inches or so, stabilize, and bring back down slowly to the reference point. Then go 9 inches, 12 inches, 15 inches, etc. Once you have mastered hovering at higher altitudes over the reference point, you can begin adding directional controls. Move your throttle forward as your helicopter hovers higher in the air. Do this slowly, and stabilize the copter after you have moved it forward 10 feet away from the reference point. Then slowly move the throttle back, thereby moving your helicopter backwards until it reaches the reference point again. You can do this with left, right, and diagonal controls as well. If at any time you feel uncomfortable, remember to first stabilize your helicopter in midair. Then bring the copter down slowly until it rests on its skids.
Summary: Apply power to your helicopter. Adjust the tracking of your blades. Adjust your cyclic trim. Get used to the helicopter's controls. Move your helicopter in the air.

In one sentence, describe what the following article is about: The name, address and phone number of the business you are invoicing should appear on the left side of the invoice, below the header. If you are invoicing a person, rather than a business, include that person's name and the address and phone number you have on file for that person. If you don't have an address and phone number for the business or person you are invoicing, include an email address instead. On the right side of the page, across from the recipient's contact information, include the details of your invoice. Write the following information on separate lines on the right side of the page: The invoice number. Type INVOICE: followed by the number. Since you are the one sending the invoice, you may choose the numbering system that works best for you. You can number your invoices numerically (1, 2, 3, 4) or by date (for example, 2010-10-16, for the year, month and day of the invoice). If you choose the latter, you can add "-01" to the end to differentiate between invoices sent on the same day. In any case, make sure you number your invoices in sequential order so you don't confuse yourself. The invoice date. Even if you choose to number your invoice by date, you should clearly write the date on a separate line. The invoice due date. If you have an agreement with the business you are invoicing about when you can expect to get paid, write that date as the due date. If you don't have an agreement, figure out the standard pay-by period in your industry; in most cases, it's 30 to 45 days. Under the invoice information, note whether you will take cash, checks, credit cards, PayPal or some other form of payment. If you charge a late fee, quickly outline this as well, if you haven't outlined it somewhere else already, like in a contract. Include your tax identification number, if applicable. Laws vary by municipality, so be sure you know your local tax code if you are to collect sales tax or some other usage tax, like the hotel tax.
Summary:
Write the recipient's contact information. Write the invoice number and other invoice information. Specify your payment terms.