Micro-Flying
Route 4, Box 369, Farmville, VA 23901 E-mail: [email protected]
Dave Robelen
GREETINGS, FRIENDS. Despite the cover date, I am writing this in January while looking out the window at deep frozen snow. The wind is blowing, and I am extremely grateful for a warm house.
I am going to diverge this month from my usual format and take a look at a new charger that came my way. I normally leave reviews up to someone else, but this piece of equipment has enough features that many of us would benefit from it.
I am referring to the Orbit MICROLADER V6.3 battery charger. Mine came from ICARE at www.icare-rc.com. They are accommodating people. The charger is physically well made with an excellent finish, and the literature — a 38-page binder booklet with a plastic cover — is quite complete.
The MICROLADER is furnished with a set of sturdy leads on the input side, and they have nice, large clips on the ends. The output side is a pair of banana jacks, and you furnish the plugs and leads. I found what I needed at the RadioShack store — except for the battery connector, which I mated to the plug on my pack. I made several sets of leads, including one for my transmitter to take advantage of the features this neat charger offers.
Any time you have plug-in leads there is the possibility of reverse polarity. The literature states that the charger is protected, but I did not test this feature!
MICROLADER Specifications
- Power supply: 11–14 VDC (car battery, minimum 55 Ah, or power adaptor, 13.8 V / 20 A)
- Operating current: Minimum 200 mA, maximum 20 A
- Low/high switch-off voltage: 10–12 V / 15.0 V
- Pole confusion protected: Yes (operation disabled if reversed)
- Connection cables: Highly flexible 2.5 mm, with pole clips in red and black
- Charging power: Step-up maximum 180 W
- Charging current: 50 mA – 6.0 A (see appendix)
- Charging voltage: 0.5–50 V, suitable for 1–50 Ni-Cd cells @ 1.65 V/cell
- Discharging power: Maximum 30 W (without cooling fan)
- Discharging current: 50 mA – 6.0 A (see appendix)
- Discharging voltage: 0.5–45 V = 1–30 Ni-Cd cells
- Battery pole confusion protection: Yes (mode won't start)
- Battery connectors: 4 mm sockets, red and black
- Calibration: via software / EEPROM
- Display: LCD, 2 × 16 characters — Volt (V), Ampere (A), time (hh:mm:ss), charge (mAh)
- Operation: Menu-controlled with on/set (double function) and up and down keys
- Message from device: Optical and acoustic
- Accessories: PC (RS232) interface 9600/8/1 including PC software (purchase separately)
- Weight (with cables): Approximately 1,200 grams
- Dimensions: 160 mm wide × 50 mm high × 140 mm deep
Charger Modes and Features
- Rapid automatic charging (Ni-Cd / NiMH): Automatic detection, two peak detection values for Ni-Cd and two for NiMH. Current is not adjustable in this mode; the charger detects battery parameters and sets itself accordingly.
- Reflex charging with soft start: Designed for partially charged Ni-Cd or NiMH cells and helps avoid memory effect in Ni-Cds.
- Discharging with automatic switch-off / current-reducing capacity measurement: Ni-Cd or NiMH only.
- Format / regeneration (Ni-Cd / NiMH): Designed for new or rarely used (old) batteries to prepare them for high-current use.
- Easy charging with adjustable current (constant current): For Ni-Cd or NiMH cells. User sets the current and the charger provides automatic peak detection. Automatic shut-off after 14 hours.
- Lead (Pb) battery charging with adjustable current: For batteries from 1 Ah to 65 Ah. Offers constant current, constant voltage limitation (2.45 V/cell), and automatic switch-off after 14 hours.
- Lithium-Ion / Polymer / Tadiran charging with adjustable current: For Lithium/Tadiran 1–6 cells and Lithium Polymer 1–6 cells. Charges with constant current, constant voltage limitation (3.45 or 4.2 V/cell respectively), and automatic switch-off after 14 hours.
Along with all these processing programs, there is a plug to connect the charger to a PC with Windows and a serial port to get graphic displays of the processes. This is an optional accessory.
Performance and Notes
The manual is a great help in learning how to access the various processing programs, which are largely intuitive and well thought out. My shop power supply is a 12 V, 12.5 A switching supply that I purchased over the Internet. The charger worked fine with this supply. After charging/discharging half of the batteries in my shop, I have a few observations on the functions.
In general, the various programs are easily accessible, and each appears to perform as advertised. I would have preferred an internal cooling fan; that would have allowed higher discharge rates to better simulate electric-drive currents. I was able to get a maximum of 3.0 A with a seven-cell pack of NiMH cells.
With so much discussion about the safe charging of Li-Poly cells, I charged several packs of different capacities and various levels of charge. In each case, the pack stayed cool and the peak detection cut off properly.
When using the automatic charge mode, the current was somewhat high (3.5 A for a seven-cell 950 mAh NiMH pack) and the battery was warmer than normal at the end of the charge. Not a big deal; I switched to using the manual mode where I could preset the current. This charger can handle all sorts of situations.
My 50 mAh Ni-Cd pack gained capacity after using the format mode, which was a good thing.
Overall, the MICROLADER V6.3 is not the least expensive choice in chargers, but it is nicely made and presented, and has an impressive array of options that should fit a user's needs for years to come.
The Medley (model)
I am going to write about models too! My latest project is a unique micro that I call the Medley. Basically, it is a medley of design shapes that I enjoyed looking at in the early free-flight models before RC became dominant. If you feel you see a particular model in the lines, that is purely coincidental.
- Wingspan: 22 inches
- Area: 72 square inches
- Weight: 28.5 grams
- Drive: KP-00 motor with 6:1 gearing and a 5 × 4 propeller
- Battery: Single 170 mAh Li-Poly
- Receiver / ESC: JMP narrow-band unit
- Actuators: DWE units from www.smallrc.com
The Medley is a sweetheart to fly. It cruises at roughly 8–10 mph and can stay inside a small gym with ease or ride the gentle thermals found around the cul-de-sac in the evening.
Since I used a design method that might be of interest, I will share what I did. In essence, I made a scale model from sheet balsa, matching the desired outlines, dihedral, weight, and CG. Gliding this model around the shop gave me a great deal of insight on the best CG, the most suitable dihedral, and the fin size to match.
To make a scale model such as this useful, several relationships need to be observed. You need to decide on a scale ratio. My Medley was already small, so I chose 1/2 scale. I could have chosen to scale the area, in which case the square root of the smaller area would be the scale ratio.
Matching the weight of the anticipated model in the miniature is helpful to achieve useful results. In this case it would be the cube of the chosen scale divided into the anticipated weight of the larger model. In my case, 2 cubed = 8, so my test model should weigh approximately 1/8 ounce when balanced.
It is practical to build the test model from light material and add weight with lead, etc., to get the desired value. This process is called "dynamic scaling" and is handy in dealing with unknown values in a new model.
After tossing the "baby" Medley around my shop and adjusting the incidence angles and CG, and trimming the fin area, I could proceed with confidence in building the larger model.
Try it and you will like it. Simple flat sheet flying surfaces work fine, and unless the fuselage of your desired model is really chunky, a thick profile fuselage is adequate. Be careful; you might get caught up having too much fun with the "baby."
See you at the field when it gets warmer!
MA
Transcribed from original scans by AI. Minor OCR errors may remain.
