Blog 3: T00 M4NY NUMB3R5
Going subsonic: Why drones have their distinctive hum and how propeller design can help fix it.
Blog 3: T00 M4NY NUMB3R5
“KPRC 201953Z 03003KT 10SM CLR 14/M08 A3004 RMK AO2 SLP130 T01441078.”
See? As promised, that’s a lot of numbers. This is what flight looks like, a foreign language to learn. There are formats for weather, airport data information, airspaces, and airplane location, all of which are completely foreign until you learn them.
The code above is a METAR, or METeorological Aerodrome Report, a standard weather report sent out every hour for each airport. By dissecting this, we will realize that aeronautics, in its 20th century invention, was strongly influenced by the communications technology of the day, meaning terse, dense language. Let’s read one “word” at a time:
- KPRC: report is coming from Prescott Regional Airport. (K stands for United States)
- 201953Z: Report sent the 20th day of the Month at 19:53 UTC = 12:53pm AZ time.
- 03003KT: Wind at angle 30° (From the NNE) at 3 knots.
- 10SM: Visibility of 10 Statute Miles (aka miles).
- CLR: Clear Weather.
- 14/M08: Temperature 14℃, dew point -8℃.
- A3004: Altimeter reading: 30.04 inches Hg. (above standard).
- RMK: Remark – Additional information to follow.
- A02: Automated weather instrument.
- SLP130: Sea Level Pressure 1013.0 millibar.
- T01441078: precise Temperature 14.4℃, dew point -7.8℃.
So now we know, the weather is clear, visibility is good, it is warm, not foggy/frosty, and pressure is good for flight. These are great conditions for flying drones, as we want not-too-hot temps, high pressure, and low humidity, which we have. And all of that was conveyed in short segments that you can parse. To see the temperature, just look for the dash “/” (or “T” for specifics) and you can pick it out easily. Same for wind: look for “KT” and you can find direction and speed. Since pressures and temperatures have pretty narrow ranges, no information is wasted on decimal points or clarification.
Learning formats and regulations is key to getting a certification, and now I officially know enough. I completed my Pilot Institute course for Commercial Drone flying, meaning I have all the info needed to take the FAA’s Part 107 test. Because of how much I’ve absorbed in such a short time, I will have to study a lot to keep everything in my head, but I am confident in my ability to pass the test. My instructors at the Pilot Institute boast having only four people ever failing the test after taking the class, and only one failing after following the study guidelines.
My exam is scheduled for 9am Monday (241600Z), and will leave me one more step in getting certification, which is to actually submit my exam to my account. After that, I will be researching for the rest of the project’s duration, interspersing any supplementary courses I want to take. Also, as promised, I completed my Push and Pull propellers, but I will discuss them next week for lack of blog space. I will print and test them next week, yielding my first practical data.
Propeller spreadsheet (nearly unchanged): https://docs.google.com/spreadsheets/d/1QnVORPgaP6eOXAQWGW8OxpOkJtlu77fsbD5rLiyG7hs/edit?usp=sharing.
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