project pattern
H
Redux
aving zeroed in on the NeuMotors NEU-F3A-1 motor as the power- plant for Yuri, the motor alone is only a part of the power system.
A Hyde soft mount will be used and is well worth the added 1.75 ounces for several rea- sons. It will extend the life of the gearbox and not only reduces noise level by approxi- mately 2 dB (when measured per AMA/FAI Pattern regulations), but improves the sound “quality” by reducing gearbox and prop resonance in the airframe. Feeding power to the motor is the job of
the electronic speed control (ESC), and a number of solid options are available, in- cluding the Castle Creations Phoenix ICE2 HV 80 ($160), Jeti Spin 99 ($269), Schulze 32.80 KA (~$500), and YGE 90 HV ($315). All are “full feature” ESCs in terms of ad- justable timing, frequency, braking, voltage cutoff, start power, throttle response, etc. Programming for each is much easier
with programming “aids”; YGE uses a pro- gramming card ($25), Jeti uses a “Spin Box” ($40), and Castle uses a “Field Link” ($30). The Jeti offers a limited amount of data log- ging (max/min current, voltage, rpm, tem- perature) that can be viewed post flight on the screen of the Spin Box. The Castle has full data logging capabilities (throttle posi- tion, current, volts, ripple voltage, watts, mAh used, and rpm) that can be downloaded to a PC using the Field Link, and viewed on a PC using the Castle Link Viewer. At the time of this writing, the Schulze 32.80 KA is out of production, and is slated to be re- placed by the Fut-M 32.80, which will have logging capabilities similar to the Castle. The Castle Creations Phoenix ICE2 HV
80 was chosen for Yuri for a number of rea- sons: readily available, lowest price, ease of programming, number of programmable pa- rameters, cool operation (even with limited cooling), and user upgradeable software (from the Castle website when updates are available). The data logging ability of the Castle has proven to be quite accurate, mak- ing it a very useful tool to evaluate motor health, battery health, and specific perfor- mance parameters of different propellers and software settings.
PHOTO: DAVE LOCKHART
The Castle Creations Phoenix ICE2 80 HV is the ESC of choice for Yuri. Benefits of this very robust and feature packed Castle ESC as well as other suitable options are discussed in the text.
An additional note about ESCs in gener-
al; the advertised weights can be a bit de- ceiving if the details are not examined. The Castle is by far the heaviest; however, the 4.2-ounce listed weight includes almost 2 ounces for 12 inches of wiring. Listed at just over 2 ounces, the Schulze has no wiring on the motor side, and requires the use of bul- let connectors on the motor leads (and the use of anything other than Schulze bullet connectors will void the warranty on the Schulze ESC). With the great number of ESCs and mo-
tors available, a bit of an ugly reality is that not all combinations work well together. The most common problems are rough starts and loss of timing at high power settings. Doing a little research with manufacturers and vendors is highly recommended if a lesser used combination of ESC and motor are cho- sen, especially with high pole count direct drive inrunners and outrunners. Feeding the ESC is the job of the motor battery(s) which is limited in Pattern events to a maximum of 42.56 volts. For a given amount of power (volts × amps = watts), it is most efficiently generated when using the highest possible voltage. At this time, the lithium polymer (Li-Po) chemistry has the
best characteristics (high energy density and power output) for Pattern use. The vast majority of full size 2-meter Pattern setups use 10 Li-Po cells in series for a theoretical fully charged resting voltage of 42. Smaller Pattern planes use lower cell counts with 8 cells being common for 1.10–1.20 sized planes, and 5 to 6 cells for .50–.60 sized planes. Battery capacity is most often 5000 mAh with some setups using as little as 4000 and as much as 5400. Configurations are either “saddle packs”
of two 5-cell Li-Pos connected in series or “bricks” of 10S cells (often with a manufac- turer installed interconnect joining two 5S groups of cells to 10S). I prefer the 5S con- figuration as it allows more versatility for mounting, better cooling, and more charging options depending on the chargers being used. The downside to the 5S configuration is a slight increase in weight (typically about 10–20 grams, or 1–2% of the weight of the pack).
Picking the “best” motor battery pack for
a Pattern plane needs to take into account a number of considerations: weight, capac- ity, continuous discharge rating, and burst discharge rating. The best pack for milder setups (Hacker C50-14XL or Q80-11S) may
by dave lockhart with algirdas ungulaitis You can reach Dave Lockhart via e-mail at
davel322@comcast.net
PHOTOS: CHRIS MOON
Long known for high end ESCs and chargers, the Schulze 32.80KA (above) is a compact ESC suitable for Pattern use and is being replaced by a new version with more features; the Schulze Fut-M 32.80. One of the newer ESC manufacturers, YGE, makes a line of performance oriented ESCs including the YGE 90 HV (at right) which is a good option for Pattern use.
38 AUGUST 2012
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