Thoughts from the workbench of Radical RC. The online retailer of electronics and kits for radio control aircraft. Dave Thacker shares his thoughts and knowledge of electronics, batteries, kit design and overall enjoyment of the hobby.
Category: Reference Sites
Links to reference information I’ve found important in my hobby.
This page intended for reference purposes and will be updated from time to time.
When trying to understand wire sizes, it’s important to understand the measurement system. Not all the world uses AWG (American Wire Gauge). Most wire available for our hobby today comes in metric, some sizes are close to familiar gauge sizes, some in-between. Most high quality wire today is not sold at an exact AWG size although some is. This leads to some confusion when trying for example to purchase wire that is “about 16 gauge” (or whatever your looking for). Because in America most people are looking for a certain gauge size, we try to list on RadicalRC.com with the nearest approximation of the AWG gauge size. Many vendors claim wire offered is larger than it is in order to exaggerate the perceived value.
To figure the cross sectional area of a stranded wire, measure the diameter of an individual strand. The radius is 1/2 the diameter. If the strands are 0.08mm (typical with the high end wire we offer) then the radius is .04mm. To figure the circular area, we figure that area for a single strand. In the case of the above example, the area* is .00502654832mm^2. Multiply that by the number of strands to get the total area in square mili-meters (mm^2). For example, our Silicone Sub-C wire has 399 of these strands. Multiplying the overly long number above x 399 strands = 2.0055927796 or rounded to 4 digits after the decimal point (proper procedure) we find the area of the 60 strand wire is 2.0056mm^2. When we look down the chart in the Square mm column we see most approximates 14 gauge.
Armed with information and a metric caliper, you figure out if your being “out figured” (hustled) or not.
The following chart is general in nature. I suspect the resistance is calculated based on single strand wire. This may be different for high strand count wire and not the subject of this article.
Check out the Wright Brothers Aeroplane Company history of Wright Airplanes. This is one of my favorite Wright research sites. You won’t believe how many aircraft the Wrights built from 1903 thru 1916. Did you know they attempted to build a biplane contendor for WWI? Yea, it’s all there. Check it out.
A calculator published by the Mogami company. It is helpful to understand wire size a little better. For example, a solid core 22 gauge wire has a different overall diameter if it’s 16 strand or 32 strand or 198 strand. Don’t get fooled into thinking AWG is the diameter of your wire regardless of strand count. Actually as the strand count of multi strand wire gets higher and higher, the overall diameter of the cable gets smaller. Think of it this way, the smaller the wire, the smaller the air pockets or gaps in the bundles of copper become. In other words the wire bundle becomes more and more dense. I run into people from time to time that think it’s as simple as measuring OD of the bundle, some get quite insistent defending their theory. We’ll perhaps they are just wishful souls dreaming about how great the world would be if it was as simple as they wish it was? Below is a handy site to help you figure out what size your wire (or any wire we sell) really is. It’s not super simple but you can work it out and learn something.
I received a forwarded email from my good friend Archie Philips in Harvest Alabama. It says in part:
“You may find this interesting, it explains how drivers pull in front of motorcycles and say ” I didn’t see him”. Lack of motion Induced Blindness (pilots and drivers too)
Good info and demo. Lack of motion Induced Blindness was presented as a flying issue, but one can also miss things (pedestrians, motorcycles, other cars) while driving, so, keep your heads and eyes moving. The below link is a great illustration of what was taught about scanning outside the cockpit when military pilots went through training they were told to scan the horizon for a short distance, stop momentarily, and repeat the process.
This was the most effective technique to locate other aircraft. It was emphasized repeatedly to not fix one’s gaze for more than a couple of seconds on any single object. The instructors, some of whom were combat veterans with years of experience, instructed pilots to continually “keep your eyes moving and head on a swivel” because this was the best way to survive, not only in combat, but from peacetime hazards (like a midair collision) as well.”
As an RC pilot, I am wondering how many pilots who fly into trees, flagpoles, barns and other objects are suffering from the same effect. I’m not suggesting you should “swivel” your eyes away from your aircraft, just be aware of what can happen. Your gaze if fixed on your aircraft may cause the stationary things in your view (things near you) to disapear or become less aware to you with the background zipping around behind your aircraft. Just a thought. Dave, Radical RC
Tapping and Clearance Hole Chart. Useful information when picking a drill bit sizes for threading or clearance fit of a fastener. Drill it right the first time. Make better & stronger threads. Courtesy of Standford University.
Edited and published by Ken Meyers, the Ampeer is probably the longest running electric flight newsletter on the planet. Lots of good information. One of the few things I subsribe to. It’s free and is published once a month. This months issue covers the Mid-Am electric fly in from which we just returned. You can see a photo of a very nice Radical RC Wright Stick that flew there and supurb shot of my Quad Copter in flight. Check it out and be sure to sign up for the newsletter. The EFO website where Ken keeps all his handy help pages and articals is linked at the bottom of this post.
Erik Dahl Christensen’s Airfoil History
If like me, you love to design aircraft and want to get a better handle on airfoils, Eric Christensens’s site is an excellent study. Click his home link to find calculators and other sailplane design information. Even if your not into sailplanes, the information is clearly presented and it’s influenced my thinking and understanding of airfoils on many levels. Studying other aircraft disciplines will help with your discipline whatever it is. I found the Airfoils section of this site very interesting. In fact, I may go back and give it a read again soon. I’m saving the link here for that purpose and to share it with you. I am currently working on my first sailplane kit and this site has helped me a great deal. Get some glue on your fingers!
Jeff Lucius provides us with his Voltage Drop Calculator. An excellent site to help understand why wire size maters. If you have a 1000kv outrunner and your voltage drop across wires and connectors is .5v then your losing 500 prop RPM. Yikes!