Fly RC

September 9, 2015

Battery Energy Sensor…

I recently got my hands on what seemed to be one of the first batch of the new Spektrum SPMA9605… known as the Flight Pack Battery Energy Sensor. Where the earlier options had been a current sensor and a voltage sensing lead, the new sensor promised to not only read instantaneous current, but to keep accumulated current draw and pack temperature as well.

I installed it into my AeroWorks Extra 260 (60-90 size) powered by a Power 60 E-Flite motor by the expedient method of simply plugging in the two EC-3s and the xbus connector from the earlier installed current sensor. Upon testing I was dismayed to find I could see no option to display the new information… Only after fussing with it at the field for 30 minutes or so did I recall that I had declined to upgrade the software in my DX-18 months before, seeing no need for any of the fixes that centered mostly on helis and sail planes. I especially did not want to rebind all of my aircraft since every previous version had required that. The latest versions promise that it might not be necessary but I had not been interested in testing that assertion.

A couple days later (tonight in fact) I downloaded the latest version and after backing up the DX-18s memories… placed the updated file on the memory card and hit the proper keys… After a couple of minutes the radio finished the process and miraculously upon power up, I had full control of the little Extra!

Even better, I now had the option to include the battery pack sensor in my display and set thresholds and alarms. I set up appropriate levels and tested the current readings and all looked promising. Since my built in temperature sensor was already in use monitoring the motor, I wanted to take advantage of the temperature capability of the new sensor.

Now, I became confused as the port labeled temperature on the side of the sensor was clearly 4 pins and the only temperature probe I had available was clearly a three wire connector… and actually only used two of them! I chatted with a supposed expert on the Horizon web site and they had not physically seen the sensor and could not help, nor did the documentation that came with the unit so much as mention the temperature port.

I had nearly given up hope of finding an answer when I finally noticed the top label of the sensor was (at least apparently) applied upside down… Where the label says X-Bus 1 and X-Bus 2 there is but one port and it is 3 pins…. X-Bus is a 4 pin connection. On the opposite side is a label Temp and on that side are dual 4 pin ports… Clearly these are the two X-Bus ports and the one 3 pin is the temp sensor!! I had already plugged in the single X-Bus port into one of the two ports on the side labeled temp it could only fit on that side. I went to look at pictures and realized that all must be this way! Someone should tell the folks on the assembly line… 🙂

Here is a picture showing the labeling and the correct wiring.

2015-09-09 21.04.58

Turning in the radio after this revelation shows the following…

2015-09-09 21.06.20 I now look forward to actually flying and testing the capacity measurement capability and am excited that I will no longer endanger my batteries by over discharging them. The closest I could do before was to set a low voltage limit which often meant I would get a warning that would sound at anywhere from 5-35% of capacity remaining depending on throttle setting at the time. I have great hopes that with this new capability I can set the alarm for a calculated 80% of battery capacity used and expect a much more accurate accounting.

I will post more as I get time to fly and test this capability.

April 30, 2015April 30, 2015

Conversion of the Aeroworks Extra 260 to Electric Power – P4

Took the Extra to the field last night and ran a couple of batteries through it. I had fear that it would become much heavier and not fly as well but that is definitely not the case. The weight is virtually unchanged… added a few ounces at most… and the plane flies very well. Power from the E-Flite Power 60 with a 16×8 Xoar E prop is unlimited vertical even when the battery falls to 15% of capacity! I have several batteries but one I highly recommend the current crop of 30C 3300-4000mah Glacier 6S batteries for this setup. Mounting the battery with the tail end butted right up against the wing tube seems to put the balance point right on or maybe just a smidge toward nose heavy. The motor, battery and Castle Talon 90 never even get more than warm after a nice 8 minute or so flight.

The best part is that I had to do virtually no trimming as this was based on an existing radio setup. I think I added (or took out) 1 click of elevator. If you have this or a similar size bird you want to electrify I highly reccomend this setup. Here are links to the speed controller, motor and prop I used…

The Glaciers seem to outperform many brands that are 2-3 times as expensive and testing on my bench definitely bears that out so far. I have borrowed a couple of the higher price packs from a friend (6S 4400s) and will try those as well very soon.

I am amazed how well the plane flies. For reasons I can’t put my finger on, I think the plane flies better with this configuration than it did with the DLE-20 gas engine. Maybe it’s the smooth application of power (the DLE has to have a crazy throttle curve to even come close to smooth throttle application) or the lack of noise and vibration. The other thing I can’t put my finger on is any gas or oil residue on the plane! Clean up is solely for the purpose of removing bugs and grass from the air frame!

Aside from the cost of batteries and an appropriate charger (but to be fair I will use both to provide power to 2 other airplanes) the conversion to electric I consider to be a huge success and actually less expensive than I expected.

Perhaps the only thing left to address is the need to remove the canopy to connect and disconnect the battery. With screws holding it on it’s likely going to get a bit tedious. I am thinking of adapting it to magnets or perhaps some sort of slide latch system. For now I’ll probably just try to get in a few more flights, get a battery voltage monitor hooked up so I can watch my battery voltage using the on board telemetry and experiment with some different props. Perhaps a current probe for the telemetry will be added as well to help choose that perfect prop. There’s always more to learn and experimenting while flying the “E” Aeroworks Extra 260 is going to be a lot of fun.

April 25, 2015April 30, 2015

Conversion of the Aeroworks Extra 260 to Electric Power – P3

Well the glue dried and I got the motor mounted using 1″ spacers, 2.5″ bolts with fender washers in front and behind the firewall and nylon insert nuts on the back of the firewall. These nuts are so much better than any combination of loctite, lock washers etc… They will not vibrate loose even in big single cylinder gas applications (only heat can effect them and that takes quite a bit).

Also mounted the speed control on the bottom of the motor box where there is a natural air flow and (by adding a hole in the bottom of the motor box) kept it close enough so the motor wires can plug right in and the battery wires can reach without any extensions. Only the throttle wire may need an extension.

Added the side air scoops as you can see above with Gorilla brand expanding glue. It’s great for many things… seems to have great adhesion to so many surfaces and materials… just have to keep an eye on it to prevent problems due to expansion of the glue. Here’s a link to the stuff I used.

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Also opened up the bottom of the airplane for exhaust as directed in the instructions.

Need to close off the old switch opening, decide how or if to address the fuel dot, work on the battery hold down and do some general clean up of the internal wiring and it will be time to do some measurements and a bit of radio adjustment. The last critical bit will be insuring the balance is on and it will be time to fly.

April 16, 2015May 10, 2015

Conversion of the Aeroworks Extra 260 to Electric Power – P2

Some small progress has been made. I stripped all the gas related equipment out the other day. This includes the fuel tank, fuel dot and associated plumbing, gas motor (DLE-20) with ignition, both throttle and choke servos, power switches (2) and the main battery (2300 LIFE that feeds both ignition and flight gear). Near as I can figure, I am taking out 2lbs 14oz of “stuff”. So far adding somewhere around 2lbs 10oz inlcuding the motor, speed controller 6S 4000mah battery and a few other odds and ends. Even allowing for another 4oz in battery tie downs etc… would make the change in weight zero! I expect the new motor to produce nearly the same thrust and I could easily afford (at a guess) to give up 20% without losing unlimited vertical. Things are looking good so far!

As I sized up mounting the Power 60 electric motor I realized I needed to strip off the firewall doubler that had been added when the DLE was mounted and close up the hole that had been cut to accommodate that setup. With a bit of judicious application of a wood chisel I am down to the original motor box and I have overlaid the front of the box with a new piece of 1/4″ plywood to provide a nice solid platform to mount the new motor to. With the added 1/4″ of the plywood and the addition of some 1″ spacers I picked up at the Toledo show, I should have the correct spacing to get the back plate of the prop adapter outside the cowl with 1/8-1/4″ to spare. I even remembered to extend the center lines that were on the front of the motor box around to the sides so I’ll have reference marks to extend them back to the front when the epoxy dries and insure the new install is also centered! Yeah me! 🙂

Waiting patiently for the epoxy to dry now… <sigh>

April 5, 2015April 30, 2015

Conversion of the Aeroworks Extra 260 to Electric Power – P1

Whilst still in the midst of converting the Telemaster to electric power… a project that is awaiting a covering job which in turn has gotten in line behind a covering job for a friends airplane… I picked up an extra speed controller and a similar but slightly more powerful electric motor for the AW 260. Contemplating this new project, it suddenly hit me that the conversion of the AW 260 is going to be quite a bit simpler than the Telemaster. This is mostly due to the fact that the 260 is in “like new” condition and was designed by Aeroworks with the option for electric power from the beginning. Here’s a stock photo from the AW website:

.60 - .90 Extra 260 ARF QB

I still have the original pieces needed to do the small amount of conversion needed (some air guides/scoops… etc…) but need a motor mount so I’ve ordered the original conversion box from AW. The ordering process was great… free shipping… nice. Then I got to the part where they charge $6 for handling… Of course I went ahead and ordered and just added an “explanatory note” to explain what I thought of advertising free shipping and then charging handling instead. I still wanted the thing and the price even with handling is not ridiculous, I could just wish for a bit more honesty in advertising… probably an oxymoron but I refuse to lose ALL hope!

Update!!! The worst part, now a couple weeks later, is it turned out that the conversion box from AW was to long to accommodate the motor (EFlight Power 60) anyway so it is pretty much useless to me… Live and learn.

In any case, I have already stripped the motor, tank, throttle servo, etc… and am just awaiting the motor box to arrive before I dig in to what I hope will be a fairly quick and simple conversion. One of my final bits of homework is to try to determine what size battery will be needed to keep this bird airborne for a reasonable (8 minutes or more I hope) period of time. I’m hoping I can use one of the pack sizes I’ve already acquired for use in the Telemaster or Carbon Z Cub. If not, I’ll be in Toledo for the big Weak Signals 2015 where I plan on picking up a new charger and a few more 6S LiPos, including some for this project. I’ll update with weight comparisons and details of the project as it progresses and hope to be able to post flight test details soon!

March 25, 2015

Conversion of the Telemaster 40 to Electric Power – Part 1

I’ve been saying for a couple years that I would eventually like to do away with all of my glow power in favor of either Electric or Gas. With gasoline being so much more affordable than glow fuel and more and more gas powered options becoming available in smaller displacements, I started divesting myself of all my 1.20 and up glow engines and installing DLE-20s or something similar. For the smaller stuff, economical options for electric power in the smaller aircraft have also become available as battery technology particularly seems to have jumped forward. For me the sweet spot for glow power had shrunk to .46-.90 size engines only. Anything else and I was looking for Electric or Gas power options for sure.

Recently I bought the Carbon Z Cub and after a few flights I realized that it might be time to once again look at what electric options were available for my remaining glow fleet. It’s power system is pulling an 8 lb airplane with enough power to provide unlimited vertical (1250+ Watts when running at the absolute max) and since I was going to be buying a few 6S LiPo packs in support of that aircraft anyway I thought if I could find a good alternative using those same packs it might be time to replace a few more glow power plants.

One of my old reliables in my glow fleet is my Telemaster 40. My Telemaster is probably 10 years old and has gone through 2 or 3 engine swaps and 2 different covering schemes. It is currently configured as a tail dragger with a Saito .82 four stroke for power which would seem to be in the same category of power as the Carbon Cub and is far lighter (~5.5lbs), even with floats attached(~7lbs). This aircraft with the Saito makes a great float plane, drop box hauler, glider carrier and sometimes just fun to fly light weight trainer. It is currently covered in Wonder Bread inspired white with colored spots and is always a big hit with the kids as a result.

The Telemaster’s horizontal stabilizer is a full airfoil design which makes it quite different to fly from most other trainers, handling much more like a cub than a trainer when it comes to takeoffs, landings and turns (rudder coordination is highly recommended). I like to think it is my skilled craftsmanship (she started out as a box of sticks, two plan sheets and 4 pages or so of small print) that makes this thing such a versatile and fun aircraft to fly but I’ve seen the ARF version and it flies great too!

After a bit of research I decided that is should be possible to swap out the Saito for a new motor and speed controller without spending a whole lot of money (assuming I can sell the Saito to offset some of the cost) and losing little or nothing as far as performance goes. In fact, most of the power options using the 6 cell LiPo batteries are likely going to be on the high side of what the .82 produces based on the research I did. It also looks like the weight of the aircraft should remain nearly constant if I keep the battery capacity in the 3000-3500mah range.

To start with I did a ton of reading, comparing specs and calculating to find out which motor and speed controller combinations made sense. I also looked for something that might be a good fit for my .90 size AeroWorks Extra 260 while I was at it. The Telemaster needs a healthy power plant to handle all the “extras” I ask of it… so something with just a bit more capability than the CZ Cub has (besides I’d like to have a bit more headroom as the cub can actually draw the rated max from the provided speed controller) maybe 1400 watts or so would be a nice target… Hopefully I can continue to enjoy nice long flights when I’m just poking around but still have plenty of authority when pulling up off the pond or hauling my skydiver up for another drop. Just a bit higher would even be enough to pull the Extra 260. It’s in the 7-7.5lb range so I’d like to have 1600 watts or so on it. With the right choices maybe I could share batteries and run a similar speed controller even if I have to upscale a bit on the motor itself.

Keeping in mind that I wanted to use my 6 cell batteries (My battery selection right now skips from about 2200mah 3S batteries to 6S 3200s!) and limiting myself to mostly what I can get through my local hobby stores, I came up with a couple of interesting options and decided to look at the Rimfire .80. My Saito turns a 14×7 with a lot of torque up to just under 8000 RPM if I recall correctly and the Rimfire calls for something in the 15×6,14×8,15×7,15×8 range and at 500KV on 6S I would expect something in the same range of RPMs… so it shouldn’t be any less capable with the new power system. Also, per the wattage, KV and Prop specifications, this appears like it will be a close match to what the Carbon Z power system does and with only a bit less wing and quite a bit less weight I would again expect to have some fairly “peppy” performance on the Telemaster. Checking weight, etc… and everything looked to be in the ballpark so I had the hobby shop order the motor and speed controller and started to work on the air frame.

Getting started involved pulling the motor, fuel tank and all the rest from the Telemaster and getting an idea how much weight I was stripping out. If things worked out well, I could install the new power system without adding much weight. The last thing I wanted was to end up with a porky Telemaster.

Here is a selection of the items that will no longer be needed.

All told this stuff weighed in at 2 and 1/4lbs and I have since found a few other odds and ends I will no longer need. Even with a fairly hefty/large capacity battery I think I can keep the overall weight close which bodes well for the project. While I’m at it, I’m stripping her down to make it easy to install the new gear and make the necessary mods to install the electric power plant. I’ll post some more as the project progresses.

February 26, 2015March 13, 2015

“Wax” coating for foam airplanes…

As I have ventured into more Electric powered flight I have acquired more and more foam aircraft. Foamies are great as they are durable, easily repairable in most cases and very light. Foam is also easier for manufacturers to shape into all sorts of shapes and allows them to mold in a lot of intricate detail if desired. Sometimes the downside of foamies is that the foam tends to get dirt and dust embedded in it, grass stains and other scuff marks etc… As well, whatever paint has been applied often wears away quickly. That’s not a big deal when the plane is the $30 variety but as the foam and electric planes get bigger, more detailed, and more expensive, you tend to become more interested in preserving them. Even my T28, which is cheap at twice the cost (but don’t tell Parkzone) gets dirty and ugly far to fast in my opinion. I am on my third and have probably 1000 total flights on them, and wanted a way to protect the latest edition.

I have seen folks using a clear spray coating of either urethane or something similar but it can damage the foam (either the spray itself or sometimes the propellant used). As well, many of these eventually yellow and are hard to remove once that occurs. Looking for something better, I ran across some information recommending a coating of Pledge Future floor polish to help preserve the foam and whatever finish has been applied to it. I hunted a bit and found the product had since been renamed and re-marketed as Pledge Multi Surface Floor Cleaner so I went out an hunted down a bottle and first did a test coat on a scrap of foam with promising results.

I have since coated part of my FlyZone Tidewater and all of my Parkzone T28 with it and I have to say the surface seems to be quite tough and very slick and shiny. In both cases I covered the airplanes by simply painting it on with a foam brush but you really can’t tell that by looking at them. I have read that many folks have applied it with an air brush with great results as well but aside from giving you a thinner and lighter coating (which may be important to you if weight is a critical in your application), I don’t think you will be able to tell the difference in finish as the product seems to be self leveling in nature and I ended up with a very smooth, slick finish on both aircraft. Here’s a view of the T28… it may be hard to tell from this but the finish is much slicker now than it was before.

So aside from a small amount of weight there are a couple possible downsides to watch out for. As I learned first hand on the Tidewater, the paint on your foamy may be soluble by the coating! Yep, the paint on the Tidewater started running as soon as I applied the “Future”. So test first with a very small amount of finish in an unobtrusive spot before applying widely. With care, I did manage to coat all of the colored areas with a minimum of runs (a bit of dabbing with a paper towel works wonders). On the plus side the T28 finish had no issues at all.

Secondly, while the viscosity of the product (just a bit thicker than water) lends itself well to application via foam brush or airbrush, it also can run easily so apply lightly. The good news is a little reapplication will often soften the area and allow the aforementioned self leveling to occur. If worse comes to worse, ammonia based cleaners will take it off so you can start over! Keep this in mind while cleaning the aircraft in the future as many window type cleaners will contain ammonia and dull or remove the finish.

Based on my experience so far, I’m planning on having a buddy do a coat of Future with an air brush for my Carbon Z Cub. He has more experience with air brushing than I so once I do a little bit of customization/decoration I plan on handing it off to him for the actual application.

If you need to get some Pledge Multi Surface to try it out for yourself and can’t easily find it locally, here’s a link to Amazon for the correct product. Pledge Floor Care Multi-Surface Finish

It’s cheaper there than I found it locally, even with shipping! I’ll update this post with my experience once flying season is in full swing. Please comment with your own experience here as well.

January 2, 2015January 11, 2015

Carbon Z Cub – Flight times, batteries, Telemetry and more.

The Carbon Z Cub flew on 3 different battery packs on New Year’s day and considering the temperature (15F or so) and the winds (~15MPH and largely across the runway) it flew quite well. Flying with a stock setup with the exception of the Dubro 6″ inflatable tires, the recommended 3200mah 30C E-Flite 6S pack kept the cub up for somewhere between 10-13 minutes. This flight was a fair mix of smooth and easy flying mixed with loops, rolls, stall turns, etc… Especially considering the temperature, I was quite happy with the flight time. Testing back in the shop showed all cells at between 3.70 and 3.74V and a recharge required 3006ma before the charger shut off and the cells stabilized at 4.17-4.18V per cell. I did not even fly to the point of voltage cut-off but I imagine I was very close!

The second battery is a GForce 40C 3700mah 6S. I flew approximately 10 minutes and later testing showed the cells at ~3.8V per cell. Recharge took 2863ma to bring the battery up to 4.19-4.20v per cell. Again, I did not fly ’till cutoff and it appears I had another 2 or 3 minutes of flight time available at a minimum.

The Dubro wheels, which add 3/4 of a pound of weight to the aircraft, may have had a minor effect on the climb rate of the Carbon Z but it was still able to climb straight up for at least a couple hundred feet and then hold a hover, though pulling up out of the hover is only possible early in the pack. I am very happy with this level of performance.

The other effect of the additional weight is a shift in the balance since the wheels are well forward. Using the Mills battery tray, it is fairly easy to push the batteries way back and keep the balance only slightly ahead of the recommended.

The cub was quite manageable in the 15 MPH crosswind… keep in mind I do NOT have an AS3X receiver in my aircraft… though I would prefer not to be flying in any stronger crosswinds!

I did get a TM1000 Telemetry receiver installed before the flight so I have records showing the receiver voltage and battery temperature for the flights. Since the batteries were kept warm before hand they mostly started around 50-55 degrees and showed a slight temp increase toward the end of the flights… only a few degrees overall. Likewise the receiver voltage was pretty stable. Staying between ~4.8-5V for the entirety of the flights.

I have some plans to add a high current sensor as well as possibly a voltage sensor on the main battery connection and altimeter. I may also move the temperature sensor to the speed controller…

Also, I got in a very short flight with a borrowed 5 cell pack. What I failed to take into account is that the E-Flite speed control is set (by default) to use 6S packs! This led to some anxious moments when shortly after takeoff, the pulsing of the motor that signals the battery is low was clearly heard! This quickly reminded me of the default setting… which I had meant to override. A bit of careful throttle management got the cub back around and on the ground safely. If you intend to fly anything aside from 6S packs, I highly recommend you reset the speed control to the “automatic/70%” setting so it will warn you of a low voltage only at the appropriate time based on the original voltage seen at power up.

Be warned that if you elect to utilize this setting, you should insure that a fresh pack is installed at each power up as anything else may fool the controller into setting its cutoff voltage to something that could easily be low enough to damage the pack if you actually reach the “pulsing” warning level.

Finally, of course I came back with more paint loss around the front battery hatch <sigh>. I intend to make some further efforts to help limit this problem but I want to get some “personalization” done first so for now it looks like just continuing to touch up after every flying session will be the rule.

December 28, 2014

Carbon Z Cub – First changes/modifications.

I’ve spent a fair amount of time scouring the forums and am currently up to about page 400 in the 1000+ page discussion of the E-Flite Carbon-Z cub on RC Groups. If you care to read all about it click here. Just to be clear, the cub doesn’t necessarily NEED any modification to fly well. It appears quite capable and fun to fly right out of the box but I’m one to “tweak” a bit on every plane in order to get a bit more out of the plane, increase the fun factor and hopefully the life of the airplane.

Using input from the discussion group and based on my own experience with this model as well as others, here are three areas where I’ve made changes to the airplane so far.

1. I continue to be disappointed with the paint. Just normal handling, battery insertion, etc.. has caused 3 or 4 areas of paint flaking off already. My first step in combating this was to head to the local home improvement store and get computer matched blue and gray, satin, interior house paint samples. Each is a half pint (probably a lifetime supply barring drying up) and cost is only about $3. It was suggested to take the two hatches in to have them computer matched… but of course I forgot and left them at home so had to find the pictures in the forum on my smart phone and have them mixed off the numbers on the labels that someone was kind enough to post. I suggest you do your own computer match instead as that has a better chance of exact matches to the paint on your cub but mine came out excellent… I was lucky. Using this paint I have already touched up 4 spots on the cub and other than a very small difference in “sheen” I’d say it is an excellent match. It does take two coats of blue to get the color perfect over bare foam. Also, it does look bright when you apply it but after drying it is a great match.

2. Bought and static tested an APC 15×6 E prop which has received some good reviews on line… Static tests indicate that a full charged stock E-Flite 3200 6S 30C pack with the stock 15×5.5 propeller is drawing 59 Amps right off charge. The cells sag to maybe 20V which equates to about 1200 Watts. 1200 Watts with a sub 9lb airframe equates to ~133 Watts per lb. For a cub… that is somewhere between high and rocket powered! In addition, 59 Amps is just under the 60A continuous rating of the speed controller and well under the 75A peak allowed so all is well with this setup. Static testing of the new APC propeller had it pulling only 54 Amps. Flight testing and perhaps some static thrust measurements will be interesting. If the APC can produce as much thrust as the stock setup and use less amps it would prove that it is simply a more efficient airfoil… If it does not produce equal or better power than I may stay with the stock prop for at least a while longer. Stay tuned on this one. Propellers are often a quick and easy upgrade and this test so far proves that you cannot use diameter and pitch measurements to compare propellers across brands. The airfoil design is key and the listed measurements from the manufacturer are to be taken with a grain of salt.

3. I purchased some DuBro 6″ inflatable tires to replace to stock foam tires. The stock tires are considered by most to be acceptable for grass fields only. I don’t even really like them on grass as they seem to have almost zero cushioning capability and the heavy wire landing gear is mounted into foam and plastic which seems like a possible weak spot. In order to protect that mounting, I am going to try the DuBro wheels with minimal air pressure. They are almost 3/4 of a pound heavier than stock so I will lose a little power/weight ratio but I can compensate somewhat by keeping to smaller battery packs (folks are running up to 5500 mah packs… so far I’m staying with 3300-3700).

I’m considering quite a few other additions, modifications, updates, etc. that I’ll discuss as I decide on and implement them. Most likely there will be telemetry installed as well as some personalization of the color scheme, flap/elevator mix testing, and more.

Right now I’m getting prepared to go flying on new years day which is currently being predicted to be a balmy 20-25 degrees(F) and 10-15mph winds… First to explore is whether I can get the Cub into the trailer fully assembled to avoid freezing fingers having to assemble in the cold!