Precision Extension Tester
New Products That Are Worth a Closer Look
Figure 1
Bruce Walker (email: brucewalker711@gmail.com) explains about the Precision Extension Tester (PET) that he designed.
A successful flight experience includes having all of your model components working properly. Many unresolved crashes are because of poor electrical connections—usually the servo extensions or receiver switches. If the airplane crashes, we don’t know why!
The extensions we use in the RC hobby are clones, not authentic Amphenol (formerly DuPont) connectors, and they are often of poor to mediocre quality, even when they are new from a reputable brand. Complex aircraft with multiple servos for flaps, retracts, ailerons, elevators, and rudders have numerous extensions that provide many potential failure points, and receiver switches are often poorly made and might only use one side of a double-pole switch, all to save cost.
Pilots who choose to make their own extensions open the possibility of an inadequate, poor crimp, which is more common than we would like to believe. A proper crimp requires a trained and experienced operator, correct equipment, and quality parts. If you’re going to make your own extensions, wouldn’t you like a device to confirm that it will function properly and effectively? My experience is that all extensions and switches should be tested, whether they are new, previously used, or custom made.
The PET (Figure 1) is a simple device that allows the user to plug in servo extensions or switches and obtain a quick measurement for each wire. It uses a microcontroller and precision analog-to-digital converter to determine the resistance across the extension or switch and display the results on an organic light-emitting diode (OLED) screen. A good multimeter cannot measure resistances below an ohm or two, so it would not be useful in finding a marginal extension or switch.
As an example, a 12-inch 22-American Wire Gauge (AWG) extension ideally should have a resistance of approximately 25 milliohms (1 milliohm = 1/1,000 of an ohm.) Anything less than 50 milliohms is acceptable. If you test the extension and notice that one of the wires measures several hundred milliohms, it likely points to a substandard crimp or excessive contact resistance.
Figures 2 and 3 are examples of good-quality and poor-quality extensions being tested. A poor-quality extension or switch might work fine in the airplane while it’s on the ground and not under load, but then it fails in flight under load or vibration.
The PET can be used in two modes: calibrated and uncalibrated. In calibrated mode, the two test leads are connected before the tester is turned on. The PET measures the resistance of the test leads and connectors, and then subtracts that measurement out when an extension or switch is tested. In the uncalibrated mode, when the test leads are not connected before being turned on, any measurement includes the resistance of the test leads; however, if the test leads are then connected, it can ensure that they have not degraded from use.
Why do we have extension and switch problems? For the reasons presented above, the quality and reliability of the extensions and switches we use are unfortunately typically poor to mediocre. Regardless of whether you buy your extensions new or crimp your own, this tool would be a worthy addition to your workshop.
The PET is produced by Ken Elder at PE Manufacturing. The unit sells for $55 and uses a standard 9-volt battery for power. It’s available through the PE2buy online storefront; the link is listed in “Sources.”
New Products From the Modeler’s Mall
BadAss 45C 7,000 mAh and 9,000 mAh 6S LiPo Batteries @ $149.99 - $179.99 + S&H from Innov8tive Designs
Tel.: (442) 515-0745
Website: innov8tivedesigns.com
To handle the current demands of Innov8tive Designs’ new BadAss 53 mm motors, as well as being a perfect match for the BadAss 62 mm series of motors for Giant Scale aircraft, the company now offers premium-grade BadAss LiPo batteries in 7,000 mAh and 9,000 mAh capacities in six-cell configurations! BadAss LiPos have true C-ratings and a great lifespan, so you will get your money’s worth from every pack. These 45C constant-rated packs are truly worthy of the BadAss brand name.
Every BadAss LiPo battery is checked for the proper storage level and individual cell balance before they are shipped to the customer to ensure that you always receive a fresh, quality pack.
These batteries are perfect for use in larger aircraft that need a little more battery capacity for higher current draw or longer flight times. They can be used with any power system; however, when they are teamed up with a BadAss motor and ESC, you have the ultimate BadAss power trifecta for your RC model!
Website: glidercgusa.com
Based on the original development of Olav Kalhovd, GliderCG is a center of gravity (CG) digital balance device for RC sailplanes that is able to provide the exact information of where the CG is located via a display that also provides information about the sailplane’s total weight. Simply place the sailplane on the scale and obtain the CG without trying to balance it on your fingers or marking the wing halves to support them on precarious structures. You can then vary the CG by moving, for example, the battery. GliderCG will automatically inform you of the new CG in real time.
GliderCG was born with the aim of being able to transfer the concept of CG digital measurement to different types of aircraft and RC gliders, so there is a specific device for each of the popular disciplines. GliderCG F3K/DLG is designed to fit small and narrow Discus Launch Glider (DLG) wings; GliderCG Plus is a special GliderCG version designed for F5G and big gliders of up to 33 pounds; and GliderCG Standard v3 is designed for F5J, F3B, and F3F models.
The system is constantly being improved and has evolved over time to provide more features and enhancements. Visit the GliderCG USA website to read more about each product in the GliderCG family.
RCX4 Mini AC/DC Multi-Function Smart Charger @ $139.99 + S&H from Hitec RCD
Tel.: (858) 748-6948
Website: hitecrcd.com
Hitec RCD introduces the RDX4 Mini AC/DC Multi-Function Smart Charger, the ultimate charger for RC enthusiasts!
This compact yet powerful charger is set to revolutionize the way you power your devices. Boasting an impressive dual-charging capability and delivering 100 watts on AC and 240 watts on DC with four charging ports, the RDX4 provides up to 6 amps of charging current, ensuring that bashers, park fliers, and avid RC pilots can fully maximize their experience without waiting for long charge times. The customizable settings allow you to tailor your charging experience to your unique preferences, and its cutting-edge safety features provide the confidence and peace of mind you deserve.
Key features include balance, standard, storage, and discharge modes for all lithium battery chemistries; re-peak charge mode and delta-peak sensitivity for NiMH and NiCd batteries; a capacity cutoff limit; a smart ventilation fan; and a built-in power supply function for powering devices up to 30 volts at 6 amps.
