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Forum 400 - April 2001

In this month’s column Pat steps outside his usual realm a bit, covering a bit more of the slow-flyer facet than normal, in addition to a few 400 related findings.

Splash

Broadening the Scope

Seems like my original focus for Forum 400 has changed a little bit here lately. Normally I strive to cover the 280 through 480 realm of motors, but on the lower-power side of things I find myself gravitating towards the indoor/slow-flyer realm during the winter months. And on the higher-power side of things, somehow my first brushless motor system appeared on my workbench! Must have been something to do with the Toledo R/C Expo in early April... Yes, I actually dove in, spent a bit of money, and upgraded from $10 motors for a change. I picked up an Aveox 1005/3Y with a Castle Creations Dragon 35 combo, and I can’t wait to try it.

So, I hope you don’t mind the strayed direction from my original focus. In this month’s column, at least, I’ll be covering a bit wider range of planes and systems. I’ve divided it up into two sections, the usual Forum 400 type stuff first, then some recent dabblings in the light-weight realm.

In the Forum 400 section, I cover the following items:

  • 1000 mAh NiMH battery (sub-A sized!) from RadicalRC
  • 260 powered Mini-Pleaser from Northeast Sailplanes
  • Aveox 1005/3Y and Castle Creations Dragon 35
  • GWS props for 400’s

And on the lighter side of things:

  • Great Planes ElectriFly Peak Charger
  • Finally getting my LiteStik up to par
  • Robbe "SlowGo" from Hobby Lobby
  • Canard Stik and WingStik
  • Castle Creations Pixie 7 Programmable controller

Forum 400

1000mAh NiMH battery from RadicalRC

At Toledo I noticed a fair amount of new batteries in the NiMH line. Of course, I’m about 6 months behind anybody else in knowing when things come out, since I’m not a very aggressive "searcher". When they’re laid out in front of me though, they’re hard to miss. I was looking for various capacities in the NiMH line to try out, anywhere from slowflyer types to good long-lasting batteries for my 400 applications, and I stopped by the RadicalRC booth in the process (check out their web site at www.radicalrc.com. They have a lot of good stuff out there). I can pretty much tell batteries by size, so when I looked at a 500mAh-sized battery pack and saw that it said 1000 mAh, naturally I couldn’t pass by without picking it up. The beauty of this pack was its identical size to the majority of what I use anyway, so I wouldn’t have to reconfigure planes or battery arrangements. Plus, I stood to gain double the flight time without adding weight. I figured I’d give it a try.

The battery was provided in a side-by-side arrangement of 8 cells, pre-strapped and cells bonded together. All I needed to do was add the appropriate leads and shrink-wrap. I’ve been using the Clearly Superior brand of shrink-wrap from Gabe Baltaian at www.nyblimp.com. I like it because it's light, has a high shrink rate, and especially for the fact that I can shrink it while holding the pack in my hand due to it’s low shrink temperature. Very easy to work with. All wired up and ready to fly:

radical-batt.jpg (43216 bytes)  radical-batt-wrap.jpg (43721 bytes)

I charged the battery for the very first time at 1.0 amp, which is just about 1C. It took 1069 milliAmp-hours on the first charge, but that that can vary from time to time and charger to charger, so take it only as reference. It was only slightly warm after charge. I also charged up an 8 cell 500AR pack and an 8 cell 600AE pack for reference for my next series of comparisons.

The 500AR was taken right off the charger and plugged into my Ferias (6.0 volt motor, 4.9x4.3 Gunther prop) through my Whattmeter. I turned on the radio and the Whattmeter read 11.5 volts without any power going to the motor. At full throttle I read 11.3 amps at 7.5 volts after a few seconds of running.

The 1000NiMh was set up next, and it had a steady-state voltage of 12.0 volts with just radio on, and then at full throttle read 10.8 amps at 7.2 volts.

Finally the 600AE pack was tried, with an 11 volt no-load reading and full throttle readings of 12.4 amps and 8.0 volts.

In flight, here’s what happened. I couldn’t monitor partial-throttle settings precisely so I decided to just test at full throttle. I loaded in the 500AR pack, set the timer and launched. After about 1.5 minutes I noticed a slight drop in power, and continued flying. At about 2 to 2.5 minutes, I was noticing loss in power and was thinking about landing. I waited until the low-voltage-cutout on the speed controller engaged, then I landed. Time aloft was 2:58. This is about what would be expected from 500mAh batteries at that current.

Next up was the 1000mAh pack. Climb was only slightly less aggressive, and was probably only noticed since I expected a lower power output due to the voltage drop of the Nickel Metal construction. If someone had handed them to me unmarked, I probably wouldn’t have noticed. I flew the entire flight full throttle again, doing the same routines and percentages of loops, stall turns, level flight, etc. as with the first battery. I didn’t notice any rpm loss after a while so I checked the timer and it read 3 minutes. I continued to fly until I noticed the first perceptible change in power and/or prop sound which occurred around 5 minutes and 20 seconds. I continued to fly until the low-voltage-cutout engaged, then landed and checked the clock. Time in the air was 6:43. Pretty good for full-throttle flight! Again, recall that this was the first charge I made and these batteries have never been cycled (aside from anything the manufacturer might do).

I then tried the 600AE pack. Climb seemed better than both the AR and the NiMH pack, but you keen battery guru’s have already figured out what I began to suspect. Either my 500AR’s are no good (they’re not that old) or they are the variety that was caught up in the changeover in construction and aren’t really the "good" ones. They are red-jacket cells, but they’ve never really performed like I thought the AR series was supposed to. It is not typical for an AE to put out more wattage than an AR! Nevertheless, the 600AE pack had the best power and I ran out of juice at 3 minutes, 10 seconds.

The last flight was the 1000mAh NiMH pack again, this time going for duration. I charged it at 1.5 amps and it peaked at 1057mAh. Talk about repeatability! I gave enough throttle for a slow climb-out and flew most of the flight about 200-300 feet in the air. No thermals to aid the flight (it was starting to get dark in the evening), and I didn’t do any motor-off gliding. It was not a calm evening either, so I bucked the wind the whole time. Still, by the time I brought the Ferias back to my feet it had been in the air for 17 minutes, 36 seconds. Too much more time and it would have been too dark to fly…

The quick analysis of it all is this: the 1000mAh NiMH held an incredibly flat discharge rate for 80% of its flight time, while the 500 and 600mAh packs experienced tapered current proportionately much sooner. Testing at full throttle (10 amps or more) is a little aggressive, but the battery delivered well. And at reduced current levels a 1000mAh battery can last a long time! Long-term analysis of the battery will take a few months, so in June or July I’ll try to remember to post another note about the performance after 20 to 50 flights.

It’s not my intention to do a full technical review of these batteries, and a monitored test would doubtless be a better comparison. I’ll leave that for the pro’s who have the complicated test equipment. But very few people would notice or care about a few percentage points of error, and a seat of the pants review is more than sufficient for those of us who could really care less whether a battery delivered 6:43 or 6:23 worth of flight time. Once you nearly double the in-air time of a NiCad, what more would you need? I like what I see in these batteries, and will be picking up a few more sets. When two charged packs will give me the potential for 30 minutes of flight in a 400 sized airplane, then I’m set! Give RadicalRC a yell at www.radicalrc.com and pick a few up. I know I’ll be picking up a few more.

Mini-Pleaser from Northeast Sailplanes

Although I was not really in the market for yet another park-flyer, a friend alerted me that Northeast Sailplanes was having a 2-day special on Mini-Pleasers. I had seen his fly and was sort of thinking of picking one up anyway, but now I was able to pick up the Mini-Pleaser, the 260 gear-drive with prop, an 8-cell 270mAh NiMH battery, and a speed controller all for $99 plus shipping. That was a fantastic deal, and you have to add on the fact that this included Deans connectors, landing gear, nice wheels, and a complete hardware pack. I was very pleased with what I received, and the workmanship was excellent.

Pleaser1.jpg (71474 bytes)  Pleaser2.jpg (81131 bytes)

The Mini-Pleaser practically fell together as I pulled it out of the box, with the tail and wing assembly taking about 5-10 minutes each. The installation of radio and control wires went extremely fast as well. When I first saw the 260 gear drive, I did a double-take, as I thought it was a 280. Normally a 280 is a low-rev motor, and I don’t usually put gear reductions on them. A 300 is almost too high a revving motor, and something in between would be perfect. Without measurements - I couldn’t get any detailed information - I would have to imagine the 260 is right in the proper range. It works beautifully in this configuration. On 8 cell 270mAh NiMH packs, power is sufficient for a nice climb, and once throttled back I can easily get 12 minutes. I would not have expected this out of a motor the size of a 260/280, but it seemed to be very efficient.

In flight, this thing kicks the pants off any other park-flyer or slow-flyer I’ve flown. The Mini-Pleaser is very efficient and actually glides for a ways, which surpasses other slow-flyers I’ve owned or borrowed flight time on. Flight is easily maintained at low throttle settings, and behaves wonderfully at all power levels. I was able to make extremely tight turns, and as more throttle and elevator were added the turns tightened even further. You have to start out slow and work into these circles, but once "in the groove" I’m sure I was keeping the circles within an 8-foot diameter.

I’ve only had experience with 2 or 3 types of "inner-driven" gearboxes, and most have been grainy and noisy. This particular one was a Horst brand and was extremely smooth. No mold flashing was evident on pinion or ring gear. The only disappointment was having to glue an APC prop to the output shaft; there was no adapter. It took a bit of work to make it run true, but once in place I zapped it with a touch of CA and haven’t knocked it off yet. The prop is a 9x3.8 APC right now, so I’m curious as to how a 9x6 APC would work.

The included speed controller in this deal was an FMA Mini-5. In reading through the brochure I found it did not have a low voltage cutoff (radio priority circuitry). With a practice run-down of the battery, I found out that flight would be difficult to maintain long before the pack voltage dropped to the point where radio operation would be affected. Always bench test first, but in this case the lack of a radio priority circuitry didn’t cause any problems. I’ve used the Mini-5 on several projects just for variety, and have yet to have a problem.

I’m in the process of outfitting it with a Glowire system (www.glowire.com) for night flying. I plug the inverter right into a spare receiver port and let the BEC power it. This works just fine, and saves the weight of an extra battery. It also saves the complexity of tapping right into the battery pack itself. I removed the case from the inverter (thereby voiding the warranty, but what the heck!) and shrink-wrapped it. It sits right above the receiver, and then I’ll run the wires in appropriate places. I’ve already flown it with wing wires alone, but I do want to add some to the tail to make orientation easier.

This is a fantastic plane, and I’ve made many flights on it. Due to my pushing the envelope, I’ve done a few "stupid" things and knocked the motor off, but a few drops of CA was all that was required to fix it. A few other less-than-stellar tricks knocked off the receiver platform, but again a couple of drops of glue cures all ills. A great deal, a superb flier, and easily repairable. That’s what all slow-flyers should be!

From Brush to Brushless

I really have no excuse why I haven’t gone the brushless route in all these years of electric flight. Probably because I’m a cheapskate at heart and enjoy flying on as little investment as possible. But the point comes where the combination of curiosity and the need for power piques one’s interest in spending more money and getting more performance. I finally did that, after 4 years into electrics. Now in fairness, I’m discounting the big 20 cell MaxCim brushless I bought for my Senior Telemaster, in that it is quite out of the league of Forum 400. The prop itself is bigger than a lot of wingspans I currently fly! But as far as a Speed 280, 400, or 600 system, I’ve never picked up anything close to that size. Once again, the Toledo bug bit me… While at Pat del Castillo’s Castle Creation booth, I looked at his Aveox motor and Dragon controller combo’s and decided to gladly part with a portion of my hobby money. I picked up the 1005/3Y motor and Dragon 35 controller, a setup that promises to turn a prop at pretty healthy speeds. With power outputs as high as 3-4 times as much 400 sized systems, I am anxious to see what this little monster will do. It calls for a radical adjustment in my way of thinking, though, as I’ve grown accustomed to taping a motor on a foam plane and going out flying for a day. With this much speed and power I’ll have to size servos properly and avoid the temptation to put a 200 dollar motor system on a 5 dollar plane.

aveox-castle.jpg (30010 bytes)

I was hoping to have this system installed in a plane and test-flown before this issue of Forum 400, but the time between Toledo and the due-date for E-Zone columns was too short for me to get anything decent ready. I’ve test run it, and it screams! More on this next month.

Great new props

Another find at Toledo was the Balsa Products booth, where they had an impressive new offering of GWS props in sizes ranging from 2.5" diameter props to 14" props. These are the orange plastic ones most people are used to seeing on the GWS Lite-Stik. They are flexible, and the smaller ones have a rather "high tech" shape to them similar to the CAM type of racing props. I should have picked up more of these than I did, because the price was only $1.00 each. I just checked their website (www.balsapr.com) and found out a lot of the ones for use in 400-sized applications are still in the $1.00 to $1.50 range. I only picked up the 4.5x4 prop for evaluation, since I was thinking of running two 4.8 volt motors in series on 8 cells and this is a great size range for this. They would also work well on the MFA Rocket motor, but since these are tied up in gearboxes on my sailplanes I only had the 6.0 volt 400 to try them out on. They have 5x4.3 and 6x3 or 6x5 props that would make good choices for direct drive 400 applications, as well as a 3x2 that might work well on a 280 direct drive. Of course if you use a geardrive the possibilities are immense, so it’s good they offer 8, 9, 10, 11, 12, 13 and 14" sizes.

gws-prop.jpg (20728 bytes)  gws-gunther.jpg (22003 bytes)

Probably the simplest way to mount these is to use a black hub from a Gunther prop if you happen to have any around. The hole sizes are the same, and it’s a quick easy way to mount them. Even though they’re pretty flexible, I’ve still managed to break a lot of Gunthers this cold winter, so I had a few spare hubs around. You can use the whole hub and if you don’t like the fit of the "spinner" you can even chop that off and retain just the bushing part.

gws-gunther-hole.jpg (21109 bytes)  gws-hub.jpg (21730 bytes)  gws-hub-motor.jpg (27397 bytes)

They run very true and smooth, with no blade tracking or vibration problems. Certainly a nice alternative to a stiff prop and shaft adapter, and much lighter as well.

 

Onto the Lighter Side

Great Planes ElectriFly Peak Charger

There’s no such thing as having "too many chargers". As I’ve gotten deeper and deeper into electrics of all sizes now, it helps to have a few extra chargers here and there to handle the variety of battery packs you might want to use in a flying session. Whether you are charging 100mAh, 600mAh, or 3000mAh batteries at their appropriate rates, there still is a minimum amount of time involved and you have to wait 20 minutes before you can throw the next battery on. When I go to the flying field or an electric meet I typically keep my Astro 110D operating at full capacity, and it handles anything requiring a 0.2 amp to 5 amp charge rate. I also have a conveniently small Multiplex Pico-Line charger that has a 1, 2, and 4 amp selection, and which works great for my 500-600mAh batteries. Since I’ve picked up a number of battery packs in the 100 to 300mAh range for the slow-flyers, I was really in need of yet another charger that would handle the fractional amperage rates required for these small batteries and free up my Astro in the process.

One charger that caught my eye for price (and subsequently acquired!) was the Great Planes ElectriFly Peak Charger. Just recently advertised, it plugs into a cigarette lighter and boasts switch-able 200mAh or 600mAh charge rates and handles 6 to 8 cells, whether they are NiCad or Nickel Metal Hydride (NiMH) batteries.

GP-charger.jpg (31134 bytes)  GP-charger2.jpg (29967 bytes)

It’s incredibly small, and it was the price and convenience which got me started down the path, but when I read the instructions I was surprised to discover some of the features this little charger offered. It will switch to a 15mA trickle charger after it peak-detects, and the red LED indicator light will switch from a steady ON state to a flashing state indicating it is in trickle mode. But what I found really cool is that the LED flashes a code to inform you how many minutes it took to reach peaked state! It will flash once for each 5 minutes of charge time, therefore 4 flashes and a pause indicates 20 minutes. This is a very convenient feature to give you the confidence you have a complete charge in your battery, and will give you an indication of a battery that has false-peaked.

The instructions indicate this charger has automatic detection of battery type (NiCad or NiMH), but I can’t verify that with any test. It also states this charger uses a pulsed current to prevent batteries from overheating. I found it did a great job in charging both battery types, and all batteries charged on it came off warm, so I trusted its detection circuitry. Furthermore, I had some older 110mAh NiCad’s that were giving me false peaks on other chargers and I assumed it was due to cell age. But those same packs gave me no such trouble with the ElectriFly Peak Charger, and I found that instead of getting 65-80mAh capacities the Astro usually delivered before peaking, I would get 120-130mAh with the ElectriFly (using a Whattmeter in-line to measure capacity). And they were a little warm after charge as well, which I had not experienced with these batteries before. Needless to say, I was pleased with the charger.

The last feature of this charger is that it will not initiate a charge if the battery to be charged has a voltage under 3.0 volts. This is obviously to protect the charger from high current spikes, but it also serves double duty as short circuit protection. Although the instructions state charging only 6 to 8-cell packs, with a 3.0 volt limit I felt comfortable in attempting to charge a 4-cell receiver pack. Don’t do this. I’ll repeat again, Don’t do this! I plugged in a 4-cell pack while monitoring voltage and amperage with a Whattmeter. Within a few minutes, the pack was peaked and the Peak Charger had a one-flash indicator showing a 5 minute or less charge time. The Whattmeter showed only 20mAh had gone into the battery, then I realized it was a previously charged pack and had peaked around 6.5 volts. So, I plugged in a dead 4-cell pack. Nothing happened, so I knew the 3.0 volt limiter had kicked in. I tried yet another pack, and the charger started churning away. Voltage registered 4 volts and climbing, then it quit within 10 seconds. Panicked, thinking I had fried the charger I disconnected everything. Luckily all is still well, but it was clear the charger was having difficulty limiting the charge current to 600 milliAmps when there was such a high voltage disparity between source and load batteries. Doing this voids the warranty if your charger fries, and that should be indication enough not to attempt it. But from a person who can’t leave well enough alone, take it from me that you don’t want to do this. It worked fine on a charged 4-cell pack where the voltage was higher, but I nearly cooked the poor thing trying to bring a low pack back to life.

There are some features a $29 charger just shouldn’t be expected to have, so it is no criticism that the Peak Charger does not have the capacity to charge higher than 8 cells. A charger capable of higher cell counts typically has to boost the charge voltage ABOVE the source battery voltage, and the circuitry to do this adds cost and complexity. When charging an 8-cell pack the pack voltage comes closer and closer to the 12-volt source voltage, and without voltage-boosting capability the charge rate drops lower. This can extend the charging time on an 8-cell battery versus the more expensive chargers that maintain a constant rate throughout the charge as pack voltage increases. Part of the remedy is to ensure you have a minimum of 12 volts at your source battery, but better yet either a 13.8-volt power supply or running your car during charge (not always practical at today’s gas prices…). But I wouldn’t list this as a detriment because it is a nice, light, convenient little charger that contains a fair number of features for the price. It weighs 1.46 oz, handles 50 through 1200mAh (AA or AAA) batteries, NiCad or NiMH chemistries, trickle-charges when finished, and even indicates charge time. I call that a good value, and better yet I call my charger dilemma resolved…

Lite Stik – "She needs more Power, Captain!"

I bought one of these Lite Stiks a long time ago and quickly bought a second one for backup. The price was right, and the motor/gearbox/prop alone was worth 75% of the price of the whole kit. Then as a myriad of Lite Stik improvement suggestions popped up, hundreds of comments were posted to the Eflight list, and even a dedicated discussion forum created, I started to wonder what was so different about mine? I was happy enough with the way it flew, but I didn’t care for the 2-minute flights. I was using 100mAh NiCads (6 pack), and that was about the limit of endurance. I tried 270mAh NiCads, and I even briefly tried a 350mAh pack (both 6-packs). I felt the power was sorely lacking, and flight suffered as a result of the increased weight. Yet, I kept hearing about "power" and "15 minute flights" and I started to think I was missing something. Even though I had heard that 8 cells will burn up the motors, I decided to sacrifice the motor for the cause and hooked up the 8 cell 270-mAh NiMH pack that came with the Mini-Pleaser above. Wow! What a difference it made. It was like new life for this thin-skinned little bird. Climb rate was measurably better, speed was up significantly, and when throttled back to 6-cell level, endurance increased. Even better, the increased capacity of the NiMH batteries resulted in very acceptable flight times. I wasn’t flying for 10 minutes yet, but it was a HECK of a lot better than the 2 minutes the NiCads provided. The motor gets measurably hotter, so it’s wise to use the power in short bursts. I’ve yet to burn up the brushes at the 8-cell currents, but even if it does occur prematurely I think it’s worth the risk. The Lite Stik is a heck of a lot more fun now than before. The NiMH batteries made such a difference that I picked up 2 more 8 cell packs at the Toledo show.

Robbe SlowGo

Okay, okay, I know you’re saying "enough with the slow-flyers already". I warned you before that this month’s column was going to take a diversion from normal… Technically, this still falls in the original category of Forum 400 in that it is a 280 motor system used. But before I begin I have a confession to make. I recall a rather politically incorrect joke whereby a certain situation was compared to riding a moped (for our International readers, that’s a gas-powered bicycle with pedals that allowed certain traffic laws to be skirted). The crux of the joke was that "They’re fun to ride, but you wouldn’t want your friends to see you on one". A similar thought comes to mind about the SlowGo. I hate to criticize anybody else’s styling of aesthetics, but first looks at this thing were like "ugh". Nevertheless, when Hobby Lobby closed them out at $29 each, I gave up on my standards and fell victim to a good deal. And actually I'm glad that I did now! Although a little on the funny-looking side, the SlowGo flies like a dream. I was really surprised, to say the least.

slowgo.jpg (32321 bytes)

There wasn’t much to assemble on this ARF. Some balsa and ply reinforcements for added structure to the foam, plus your typical pushrod and control horn installations. The spinner assembly was a neat idea in that it faired in the nose nicely, but it was a nightmare to put together. I succeeded in getting it to run true but spent as much time on the spinner alone as the whole rest of the plane. And to add insult to injury, it amplified the gearbox noise to almost painful levels. I couldn’t run it indoors at night for fear of waking up the kids. Granted, the included gearbox (no name on it) was grainy and this didn’t help much, but having a spinner of this size and construction was just asking for noise to be generated.

I decided to use a 350mAh battery pack, as current draw was in the 3-4 amp range when swinging a 10x7 APC slow-flyer prop. Out at the field, I prepped in the usual way for the first flight. I then powered up, threw it lightly, and was airborne with no problems. Very predictable control with nice habits, smooth turns, and even a fair bit of self-recovery. First flights were made on a windy day, so I didn’t get too low and slow. But on the second night I went out in perfectly calm conditions and had a blast. It slows down nicely and still maintains rudder control at low speed. I was even brushing the wing tips through the grass in low-level circles! It makes a fun calm-weather flyer, and would be a real hoot indoors.

I used the geared 280 drive on it, but I’m curious as to whether the GWS drive would still pull it around okay. Even though the fuselage is a little on the chubby side, it is fairly streamlined. Perhaps an experiment for another time, I guess. The SlowGo weighs 9.25 oz without the battery. The 8-cell 350 battery weighs 3.75 oz, for an all-up flying weight of 13 oz. On that big fat wing, that results in a pretty low wing loading. If I switched to the GWS drive, I could save 3 oz in the motor and prop, and the NiMH battery would weigh 1.5 oz less than the NiCad. That would make the flying weight 9.5 oz! I’ll let you know how that goes some other time. If it pulls it around okay, I’m wondering if it would EVER land when the battery ran down?

Canard Stik

Remember why I bought two Lite Stiks? Well after having them both in "normal" setup, I decided to bash one just for kicks. On this project all the components were the same as the original, just moved around for balance. A modified elevator, a new position for the rudder, and I was all set. Did it fly? Yes!

CanardStik.jpg (45206 bytes)  CanardStik2.jpg (47134 bytes)  CanardStik3.jpg (39225 bytes)

I didn’t spend much time on it, or even figure out where the balance was SUPPOSED to be. But I flew it around and it did okay so I must have been close. A very weird looking bird in the air, I must say. It was fun, easy to do, a bit touchy to fly, but it was worth the time spent. And it also subsequently led to my next iteration, the Flying Stik.

WingStik.jpg (30555 bytes)

Still a work in progress, I’ll let you know how it goes. Rather than using elevons out at the tips and the resulting linkage hassles, I’m going to use dihedral in the wings and control it with rudder and an inboard elevator.

Pixie 7 Programmable controller

I have a lot of Castle Creations controllers around the house, varying from Pixie 7’s, Pixie Lite’s, a Sprite 25, and just recently a Dragon brushless controller. The Pixie 7’s are my controller of choice for all slow-flyer projects, and I occasionally use them in tame 400-sized projects as well.

pixie.jpg (15895 bytes)

Well, Pat del Castillo has been keeping the REAL Pixies and Sprites slaving away in that mythical dungeon of his again, and they are getting quite good at computer code nowadays. Just recently announced is the Programmable Pixie 7, which offers such features as:

  • Programmable low voltage cutoff (none or your choice of 4 voltages)
  • Programmable motor cutoff type (soft cutoff, or hard cutoff with reset)
  • Programmable throttle range (fixed end points or self-calibrating)

And the above are in addition to the following standard offerings:

  • 0.007 ohm resistance
  • 2800 Hz high rate switching
  • 7 amp continuous use
  • 1.2 amp BEC output
  • 3 cell to 18 cell use (see instructions)
  • safe arming
  • soft start
  • auto shutoff at signal loss or degradation

At first I couldn’t tell the difference between the 7P and the regular 7, but once power was applied the miniature LED lights up rather prominently (…might also serve as a good locator beacon when I lose it on my workbench!). The LED serves as your communication mode when programming the controller.

Programming the Pixie is easy, and you follow just a few simple steps to enter programming mode. The setup used is such that you can’t accidentally enter programming, so don’t worry. Once you are in programming mode the instructions give you the sequence of "questions" the Pixie will ask you. The response for each section is simply a "YES" indicated by full throttle position on your transmitter, or "NO" which is indicated by off throttle position. The "proceed to next question" is indicated by a center throttle position. Pretty easy to follow, and the instructions walk you through it easily.

The programming choices offered make sense, and increase the flexibility of this already microscopic controller:

For instance, with Low Voltage Cutoff on a typical 6 or 7 cell pack the standard cutoff voltage of 4.7 volts wouldn’t take the battery voltage down too far, which with some battery chemistries can damage them. On a 10 cell pack, a 4.7 volt cutoff would leave the batteries at 0.47 volts per cell, which is harmful over time to even the typically robust NiCads. So you would want to pick either the 6 volt or 8 volt cutoff to leave batteries at a more reasonable 0.6 or 0.8 volt per cell condition.

With the Motor Cutoff choices, you can select a low battery indicator that is to your preference - either the option that cuts the motor off completely and you re-arm with the throttle stick, or the option that allows a progressive shutoff to the motor by slowly reducing its speed.

And finally with the Throttle Range choice, the option is provided to switch out of auto-calibrate mode and go to a fixed response mode. According to Pat, this is beneficial for helicopter tail rotor control where fixed response is preferred.

Now, if we lean on him real hard we might see some of these programmable features in the larger controllers, right Pat?

Charger Cases / Battery Cases / Transmitter Cases

A shameless advertising plug here, but hey, I don’t get paid for writing this column!

If anybody is interested in some nice carrying cases, let me know. Small ones are $3.00 each, large ones are $5.00 each. They’re strong, foam padded, with nice hinges and positive latches. They fit Astro chargers perfectly, and the larger case will fit two Astros comfortably or even a larger charger. Some transmitters will even fit in the larger case, such as a Cockpit or a Hitec Focus III. Either size case works wonderfully for carrying battery packs around, too.

Charge-case.jpg (42322 bytes)  large-case.jpg (58787 bytes)

battery-case.jpg (57685 bytes)  cockpit.jpg (25865 bytes)  isl6.jpg (32183 bytes)

Ordering and shipping information at: http://hometown.aol.com/pimatte490/cases.html

Spring is here, get going on those projects!

See ya next time,

Pat

 

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