Spektrum NX10 failure analysis and repair

In a previous post I reported on the demise of one of my favorite airplanes.  The Top Flight P47 60-90 size ARF.  The cause of that crash was that my Spektrum NX10 powered off mid-flight.  This is disappointing as I have run the NX for several months and been extremely happy with it.  The radio link to all of the planes as I  flew them has always been rock solid… well at least while the radio was on!

After the crash, there was no doubt the radio had turned off unexpectedly.  So began the investigation.  I posted online about the failure and found just two folks who had claimed to have something similar occur and none had an occurrence during flight. 

Thinking back, I honestly believe I may have seen it happen once on the bench shortly after first receiving the radio but at the time I was on very early code and was still learning to use the thing.  As it happened I was working on a setup of an airplane and turned away for a few seconds to check something else behind me… an email arriving on my computer or whatever… and when I turned back the radio was off.  I was so uncertain at the time as to the sequence of events that I passed it off as “perhaps I turned it off without thinking or realizing it when I got distracted”.  I really couldn’t believe the radio turned itself off and I never saw it again through setting up 20 or so airplanes on it, multiple upgrades, template creations and many flights on many airplanes later I hadn’t seen it again so had forgotten about it and moved on… until it did it again and my plane crashed.

Online I got the usual advice and questions… folks trying to helpful asking about battery state, shake tests, testing the on/off switch, etc… and I did as many of them as I could justify or understand to no avail.  I tried to jiggle the battery and connector particularly looking for an intermittent connection from the battery but it stayed on solid through all the shaking, wire twisting, switch tapping etc… that I could figure a way to inflict on it.  In a few days I acceded to inevitable and sent it off for repair with fingers crossed.  I spent years troubleshooting network for a living so I understand troubleshooting software and hardware systems like this when there is no no repeatable test case and no apparent error (other than a pile of wreckage) to be seen is an extremely trying task so I held little hope.

Now on the forums there are several very respected folks who monitor and comment on things and one is a gentleman who actually works on the software team for the NX series radios.  Andy, like others, recommended sending it in and contacting them to discuss it.  After the radio had been in their hands for a few days I reached out to him to try to figure out the easiest way to reach whomever was testing my radio.  I knew that the best chance of getting a fix was to give them as much information as possible and the online form only allows so many characters so I gave Andy a complete description of the issue and asked for his advice on how to get this to the correct people.  I also tried to impress on Andy that I really wanted a resolution beyond “no problem found” as I would never commit another airplane to flight with that radio unless we could determine a cause and apply an appropriate fix.  I also explained that I have been a pretty loyal Spektrum user for many years now and have purchased many Spektrum radios and spend a fair amount of time helping my fellow club members get the most from their Spektrum radios.  I really didn’t want this story to end with “…and that is why I have a $500 radio that sits in the corner and gathers dust”.  Returning it to me in that state would be a waste of postage.  Unsaleable and unusable…

Just a day later I got the notice that Horizon had sent me a shipment.  I feared the worst… then came the invoice for $0 and a note that they had decided to simply replace my NX10 under warranty!  Is this the best of all outcomes… no.  It is however the best response that I think Horizon had available to them and I commend them for excellent service once again.  I’m sure they tested my radio and had no way to recreate my issue.  I ran it for months and only saw it happen (maybe) twice and the circumstances of each were different.  I’m sure both Horizon and I are hoping it was simply a one in a million intermittent hardware issue and neither of us will ever hear anything like it again.

Horizon even went so far as to transfer all my models over to the new radio and upgrade the software to the very latest version.  They also sent me a complete new kit… radio, battery, strap, etc… all the stuff that comes with a new in the box system…. even though I had only sent them my bare radio minus batteries etc…  Of course they cannot replace my airplane.  That is simply asking to much and lets face it; if you can’t handle an occasional loss of an airplane you probably need to get out of the hobby.  They did more than I think is reasonable to expect in a bad situation and I appreciate that they are electing to take care of a loyal customer such as myself.  I have experienced much less satisfactory service from companies who have gotten a lot more of my money but Horizon seems to get it right more often than not so I will continue to support them and spend my money with them as often as I can.  Thanks to Andy and the rest of the team there.  You guys do it right.  Thanks again.

So I now have a brand new NX10 and am starting to get my planes bound to it and ready to go.  My Timber X is back on the NX10 and flew well on the first couple of test flights…. It may be a bit before I put the 12S powered Aerobat or the 1/4 scale cub back in the sky with the new radio, but as my confidence in the radio recovers, I’ll be moving everything back over.  Fingers crossed this will be the final chapter in this saga.

Top Flite 60-90 size P47 ARF… Final flight. Spektrum NX10 failure investigation begins.

My Top Flite P47 was a super flying airplane with a great power system and has been performing flawlessly.  I have been testing out some different props to determine best mix of power, speed and flight times attainable.  Have broken a few props but otherwise she was running great.

Unfortunately all good things must end and a couple weeks ago she ended a flight looking like this.

No photo description available.

Here’s how it went.  On takeoff, I started a nice steady climb and flipped both the landing gear up and flaps up switch.  As you can tell in this photo, the gear cycled all the way up successfully and I’m confident the flaps did as well from the way the it was flying.  I then made a left turn and was nearly in knife edge when I suddenly realized I was no longer in control of the airplane.  The plane was sliding on its wingtip toward the ground and nothing I could do with the sticks had any effect.  Being electric and a good way out I heard nothing other than a sickening crunch after it disappeared below the corn stalks…

In disgust I dropped my gaze to my radio and was surprised to discover there was no display and no lights whatsoever!  I removed my sun glasses to be sure and verified the radio was indeed off.  After walking back to a seating area (I needed to sit down) I turned the radio back on and it powered up normally and showed the battery was at 4.0 volts which is in the range of 80-90% of it’s full charge state… i.e. the transmitter battery is not dead or even low.  I then tried to figure out if my neck strap, clip or some placement of my hands could have turned the radio off and I cannot imagine how to make that happen while going through the maneuvers that I performed.  It takes a good 4-5 seconds of steady pressure on the power button to turn off the radio and in that time period before the plane stopped flying I had flipped two switches and moved both sticks to adjust throttle and perform my turn.  Try that and tell me if you can do it, even if you try!

After a long walk in the corn locating the “remains” I started reclaiming all the parts and considering the wingtip and nose in a near knife edge collision to the ground, the components aside from the airframe faired as well as could be expected.  The speed controller had a fan mounted on it… That plastic frame did not survive but the replacement is $10 and the speed controller itself has tested out to be in good condition so far and does not have a mark on it otherwise.  The receiver is likewise undamaged and tests good as do all the servos.  The motor had the worst result, being a bit dirt caked and the main shaft turned out to be bent.  I’ll post on that separately.  The retracts, as you can see in the photo were safely retracted before the loss of signal occurred and also seem to be unscathed.  Even the two batteries (a 6S 5000 and a 2S 5000 run in series) look in good shape and still charge as before.  As I said, things survived pretty well aside from the air frame.  It is a total loss with only the tail surfaces seemingly intact.

As you can imagine, this started a serious investigation into why the radio shut down.  I’ll post a new entry about that soon.

So ends my favorite war bird to date.  There will be a replacement of some sort soon!  Here’s hoping your flights are more successful than this one was.


New Radio – Spektrum NX10

NX10 Arrives

NX10 10-Channel Transmitter Only

Since February 2018, I’ve been primarily flying using the Spektrum iX12 transmitter.  I’ve certainly developed a love/hate relationship with the iX12 over the past 3 years.  I’m not overly fond of a touch screen  interface on a screen this small, the slow power up can occasionally be annoying and if you try to rush it you frequently run into disconcerting delays and seeming instability that requires a fresh shut down and restart.  Additionally, running anything more than the basic Airware app on the radio seems to be asking for trouble as the platform is just barely adequate to run it… let alone adding anything else into the mix.  On the other hand, the text to speech option really makes spoken prompts far more useful and the display is sharp.  Additionally, the built in WiFi and Bluetooth on the iX give you have capabilities that no other radio in the Spektrum line can match.  Wireless headset use, keyboard and mouse connection, direct download of updates, etc… Bottom line, while I can work with the iX12 and it has its strengths, it occasionally frustrates me so I decided when the NX line came out I’d grab a possible replacement and give it a try.

So in November 2020, I ordered an NX10 from my local hobby store.  As usual they gave me a great price and didn’t ask for any deposit or credit card to get my radio on order.  While I waited for it to arrive (first predicted to be in by mid-December) I read up on the discussion groups, watched videos about the NX line and weighed my options on which radio I would get rid of to pay for the NX when it arrived.  I had both an iX12 and a black addition DX9.  I’ve always liked that DX9 but 90% of my airplanes were setup and working on the iX12 so I started out by taking the DX to a couple of swap meets and it found a new home quickly.  In fact it paid for a majority of my NX10 purchase as that radio is still very popular and I had the charger, manual, original strap and pretty much all of the original accessories it came with along with the case.

In February, the NX10 arrived and it is pretty much as advertised.  It feels good in the hands, especially to those who like a bit lighter radio, even with the large 6000mah 1S LiIo battery on board.  The weight is a big point of contention on line in the forums but I find it a nice balance between the heft of a DX18 and the almost disconcerting lightness of a DXe for instance.  I like the dark, mostly matte finish of the radio and I hope we never go back to radios with all the chrome on the front… at least not as long as that chrome is applied to a plastic base!  That is the worst of both worlds.  Easy to damage, flake off, etc… while also being shiny enough to blind you if the sun hits it just right while you are trying to look at the front panel for whatever reason.  The NX display is a bit sharper (higher res) than the DX line though not quite up to par with the iX and the added colors of the NX versus the DX are pleasing though you have to be careful to avoid color combinations that work great indoors but are totally washed out and nearly invisible in the light of day!  Not up to the iX12 standards with the capability to show pictures, etc… but still an improvement over the DX monochrome display.

The sliders on the back of the radio are a disappointment to some and I can definitely attest that they are not smooth by any stretch of the term but for me they simply don’t matter as I have never found a real use for them anyway.  If you are a fan of sliders and expect a smooth control akin to a volume control slider on an audio mixing board, you have come to the wrong place!  Of course they work.  They just don’t have high end feel to my fingers… I suspect these are the same as what the DX had and I don’t recall the iX being distinctly better either but then again I just don’t use them.  Maybe someone who does can comment with a better comparison.

The gimbals feel fine and they have all the usual adjustments which are all reachable via front panel access to the various trim screws.  That front panel access is a nice change from many previous radios which require taking off covers etc…  If you tend to just live with the feel of the sticks the way the radio comes out of the box you will have no throttle ratchet and the throttle seems a bit “grabby” to me… not very smooth and this is again something that a vocal minority on the forums have brought out as a flaw with various solutions put forth.  For the vast majority of aircraft fliers I suspect a quick adjustment to enable the ratchet and adjust spring tensions to suit your preferred feel will be in order and will result in a good experience for the vast majority of aircraft fliers.

The NX10 has the hall sensors versus standard pots.  I haven’t noticed an different feel but I know the hall effect are considered higher end/more reliable so they may prove themselves over time but don’t expect to be able to tell a real difference just from pushing the sticks around.

The best and worst of the comparison between the NX10 versus my iX12… as far as what matters to ME are as follows:

I continue to miss the flexibility of the text to voice capabilities of the iX12.  Having to use canned responses that aren’t intuitive to me or sound too much the same so that I have to actually concentrate on what the radio is saying are just not even half as useful to me.  Someday we have been told they will upgrade the sound editor that was available for the DX radios and that will fill a big part of the gap for me but until then, this will be the biggest drawback.  Assigning them can be a bit tedious as well… having to scroll through long lists of prompts or build your own list but its not something I do that often so its not a critical shortcoming.

Otherwise there are many things I like much better. 

First, I have no need and do not enjoy using the touch screen on the iX12.  It’s to small for my big hands, though very sharp to look at.  The radio can also lag behind when trying to quickly move through menus and make adjustments and takes far to long to boot up.  I’ve heard all the excuses as to why, all the workarounds to try to make it better etc… and I just feel like they really missed the boat by handicapping the 12 with such an underpowered platform.  I can boot up the NX10 and configure a new airplane by the time the iX12 boots up and becomes stable!  OK, maybe that’s an exaggeration but not much of one.

Also, the battery life on the NX10 with the shipped battery seems to be much better than the iX12 which has to remain on, albeit in standby mode, the whole time I’m at the field unless I want to wait 5 minutes to boot it every time I fly.  By comparison the NX10 is ready to go in seconds.  You can buy an aftermarket battery for the iX12, which I did, but that makes it a bit heavier and is another expense for something that they could have done out of the box.

The use of WiFi in both radios is great.  Comparing to the iX12 they are a close run thing but I actually prefer the NX as the WiFi setup is all inside the user interface versus having to go out to android and connect to WiFi and then jump back into Airware and do what you want to do and then back out to disable, etc…  This allows easy registration and upgrading which is great.  The lack of Bluetooth in the NX is a small disappointment but not huge as the interface of the NX (very DX like) only rarely would benefit from having a keyboard/mouse connected and there are Bluetooth converters available if you really want to have headphone connectivity.  Again an aftermarket expense but understandable in this case as the Bluetooth in the iX was available largely due to the Android platform.

There are other things I could discuss but I’ll end with this one.  The NX allows for easy USB connectivity to a computer.  This enables simple connectivity to some flight sims and games and also gives access to the internal storage area of the radio where models and templates are stored etc…  That means there is another simple avenue for backing up or uploading airplane configurations, etc… 

After a few months of using the NX10 I moved forward with my conversion and sold my iX12 as well.  I had found I could do all I needed to do with the NX10 and had come to enjoy using it while the iX became a fixture sitting in a corner of the shop, unused.  I took that money and bought a “backup” NX8 which after registration and loading of my existing model setups, sits in the case waiting for the day I need a “backup”.  Occasionally getting use as a buddy box or loaner radio to my friends in need.

One final note.  Getting from an iX or DX radio to an NX platform is easy as the iX can read iSPM (iX format), NSPM (NX format) and SPM (DX Format) files and write either iSPM or SPM format.  The NX can read all three types  but only writes NSPM format files so going back from an NX to a DX is not quite so quick and easy as a DX files are SPM format only.

In summary, I’m all NX now and just waiting for improvements to the sound capabilities down the road.  There have been a few bug fixes that have come through for some small annoying things like scratchy sounds and little roller glitches but since upgrading is so easy and none of the other fixes have really much affected me I just stay fairly current and keep flying.  If I ever hit the lottery I might be tempted to go to an iX20 but it isn’t something I see happening anytime soon as the value just isn’t there for me and the NX has been such a good experience so far.

Spektrum connect issues… resolved?

One of my largest aircraft currently is my Extreme Flight 74″ 12S powered Laser.  It is also one of my favorites due to ease of assembly at the field, unlimited vertical performance and the fact that it is capable of such beautiful aerobatics!  Sometimes it even looks good when “I” fly it!  Yep, the plane is certainly more capable than her pilot.

Really the only issue I have had with this plane for quite some time is on that occasion when I get it assembled and ready to fly… except the iX12 radio and 12 channel power safe receiver will not connect on power up!  It’s very frustrating.  It’s not that it has lost bind…  I’ve occasionally gotten it to work again by cycling power once or twice or even just taking it back home and trying again…  It’s was never obvious what I actually did to fix it… and sometimes it seemed nothing would.  It happens very rarely and usually if I just go through a rebind process it works perfectly from that point on for a long time.  This typically only occurs if the plane has been sitting idle for a period of times… week or months (like first flight of the spring) is the most likely time to have this occur.

So being as it is just getting to be good weather for flying on any kind of consistent basis here in Indiana, I just ran into this issue again!  This time I was at home and had decided to tinker a bit with the Telemetry when it once again refused to talk!  Power up the radio, power up the plane, pull the pin switches for both receiver and speed controller and… nothing.  Everything is sitting at centers and the usual sing/buzz from the servos but no link…  

I tried a couple of power cycles and still no luck so this time I decided to post on the Spektrum group on Facebook.  After several posts back and forth and a number of excellent suggestions, one gentleman pointed out that the power safe receivers would not link to radio if the proper number of remotes (he even said if just the A receiver was down, that would do it)  didn’t come on line and suggested checking the contacts and coating them with electrical grease to shield them from problems.  An intriguing idea so I went back to the airplane and did some more testing.  As I did so, I also noticed that I had not done my normal strain relief on these cables so I decide to take care of that before all was said and done.

What I found was that in fact the A receiver was certainly not linking up (no lights if I recall correctly… or at least no steady light) and once I re-seated the cable, everything linked up instantly.  Repeated testing showed it all working perfectly from that point on.

I have a fair amount of pride that few of my planes crash due to “avoidable” assembly and maintenance issues so I like to track these issues down and resolve them whenever possible and then apply the fix wherever it makes sense on the rest of the fleet.  This airplane for instance has redundant flight packs separate from the power packs that run the motor, nylon insert nuts on all of the ball linkage bolts, Telemetry monitored battery levels, etc… in order to make sure it is as reliable and survivable as is possible/reasonable.  So I decide to see if I could eliminate this issue for good.

After collecting the necessary items (all shown here except the liquid tape) I started to work to resolve this issue.

The process went something like this…  First pull the remote receiver (they are all attached with sticky back Velcro, so this is not hard to do) and the cable from the airplane.  Inside the box (I’m working in the living room so protecting the furniture/carpet from harsh chemicals and spills) I spray some contact cleaner into the end of each cable connector and into the remote receiver connector.  Once dry, I took a toothpick and forced some dialectric grease down into the holes on the cable connectors and then coated the pins in the connector as well.   I did the same on the receiver while still installed in the airplane… luckily it’s somewhat roomy in there… and then reconnect everything and wipe away any excess that squeezes out.

That should eliminate the possibility of corrosion in the future so once all was back in place I moved onto painting on some red “liquid tape” right on the back of the connectors and onto the first 1/4″ or so of wire for each of the four cables that connect to the remote receivers.  This helps to share the stress on those wires and eliminate the most likely break point for the connections.  The liquid tape will flex but doesn’t allow for kinking or pulling on the individual wires.  I have had a few of these wires break before but never had an issue once I applied this little “hack”.  I apply this while everything is plugged in typically.  If a bit gets on the receiver or over the outside of the connectors it doesn’t hurt a thing and simultaneously it can’t get in the way of the actual electrical connections if applied this way.

Here are the two plugs on one side of the receiver.

And here is one of my receivers sitting on top of the motor box under the cowl.  You can see how I have coated the connection, further protecting the wires against stress and contaminates to some extent.

We will have to wait and see how this works out.  I have high expectations that this problem is likely resolved and I feel very positive that this improves the likelihood that this plane will fly for years to come… or at least until I make a mistake behind the sticks!

Spektrum iX12 – 1 month in…

Image result for spektrum ix12

One of my more recent additions to the RC hangar is not a new airplane but instead a new controller.  I have been using a DX18 for a few years and have found it to be an excellent radio.  I have zero complaints operationally with the 18 but I really like the newer designs that have come out without all the excess “chromed” plastic.  What’s the point in putting a coating over plastic that will eventually wrinkle/peal and otherwise just create issues?  It looks nice if you like chrome I suppose… never a big draw for me… and sometimes can create glare issues on especially sunny days.  Also, while not a big fan, there are times when a voice notification would be welcome.   I’ve held off because previously they were rigidly defined.  Want the radio to say “charge my battery!”?  Sorry, the only message available is “low battery”.

Spektrum’s approach of putting an Android tablet functionality “up front” in the iX12 sounded like it would have some nice advantages and I haven’t yet needed channel 13 and up on my DX18… so after a bit of research I took the plunge.  Hey, it’s a hobby!  If I’m going to get a little closer to the “bleeding” edge of technology in some facet of my life, this is the place to do it.  So after some time with the radio here is what I have observed and what I’ve done so far.

So far, I have had zero issues… I am somewhat familiar with Android so I think I have avoided some of the odd issues that folks on some of the forums have reported.  I moved 16 models over from my DX18 Gen 1 and everything has worked great so far.  I’ve flown a couple small quads plus 4 or 5 indoor airplanes and other than messing with the spoken prompts, I haven’t modified my setups at all.  Generally, I like the look and feel of the mechanicals of the transmitter.  If you’ve ever handled a DX9, you will find much of this radio to be very familiar.  Some parts of the box are even better, like the back sliders (which I rarely use) being much smoother.  The UI is not yet totally intuitive to me but I’m getting accustomed to it quickly.  I am beginning to like the text to speech options though I wish the audio defaulted to all OFF.  Will probably build myself a template for future use to accomplish this.

The radio is not capable of terribly loud audio levels and some have complained about that.  It certainly is not capable of the same volume of the DX9… Of course folks complained about distortion with the DX9 so Spektrum may not have been able to win this one!  Volume is not an issue for me as I intended from day one to use a blue tooth headset as I hate hearing the constant chatter of audio from other folks radios while I’m trying to fly.  I like to hear my aircraft (and others) and all that chatter is distracting and irritates me after a while.  I also think it impedes communication with my fellow pilots as needed for safety so I love the blue tooth headset option afforded by the Android interface. 

In order to make the audio usable, not annoy my fellow pilots and maintain safety I intend to use a single earpiece.  I bought the Sentry BT950 so I can use whichever ear I like… So far I like how it sits on my neck and audio seems plenty loud.  I have a couple other Bluetooth sets so I can try some others if need be but this one is a nice cheap option I can afford to leave in my flight case.

I also picked up an inexpensive blue tooth keyboard and mouse (Logitech model K380 and model M535, refurbished).  Both paired up and worked right off.  One oddity that was noted in some of the forums was apparent immediately.  When used in conjunction with the iX12, the enter key doesn’t function as you would expect.  So far the esc key seems to function in place of the enter key for text entry.  I’d bet there is an app that would remap the keys for me but I’m OK with using the esc key for this purpose.  The mouse works great and even has a “gesture” button that can be used to do swipes and such so you can pull up the various “side” menus etc… I’ve only used the mouse and keyboard a bit during setup of new aircraft but so far it seems like a great alternative to using the screen based keyboard to create all the text to speech prompts, timer call outs etc…  Do I need them to accomplish this?  No, but I like to have the option for anything that is going to require much typing.  I don’t even like to send long texts on my touch screen Android phone so having a keyboard is a nice option for me.   All my blue tooth hardware total cost me $70 and I will use some of it for other things so in my mind they are cheap at the price and nice to have options.

I routinely pull pictures directly from the web using the Chrome browser on the radio to use as my icons in the model selection screens and downloading the updates from google play is a nice and familiar way to operate so the ability to connect to a WiFi network directly from the radio is another nice to have option.  All in all, I like the radio so far.  There have been complaints about some issues (minor for me) like the audio level, slower model selection than other radios (30 seconds to change models versus maybe 5-10 on most radios) and the fact that it takes about 2.5 minutes to go from powered down to fully functional the first time you power up at the field.  This last is something you adapt to fairly quickly.  Just turn it on when you get to the flying site.  By the time you get a plane or two out, all is ready to go.  During the day, simply double tap the power button and go into sleep mode after each flight.  Coming back to full power up from there is a couple seconds.  The battery will last all day using this routine. 

As I worked with the radio a bit there were a couple of additions I decided were worthwhile.  First, there is a company (Powerhobby) who sells vinyl wraps for the face of many transmitters including the iX12.  I have occasionally dropped something onto the face of my transmitters in the past and I thought maybe this might give it a bit of extra protection.   Also a little individuality never hurts… I already know of one other guy in the club who has an iX12 on order so now there won’t be any mistaking mine for his!  Installation of the vinyl was a bit tedious but not terribly so and I think the result is pretty nice.  Here is what mine looks like after the application.

In addition I quickly noticed that the touch screen was going to often get greasy and spattered, etc… so I decided to take the leap and try to find a good screen protector.  I have not had great luck with the cheap plastic sheets you get for cell phones… they either mute the sensitivity of the screen, cause visibility issues, etc…  so I looked for a glass cover for this use and actually found one sold through Radiocontronics.  It is made of something marketed as “AirGlass” and is apparently from a company called Brotect.  I hesitated to spend ~$24 with shipping for what looks like a highly hyped piece of plastic cut to shape… but I have been pleasantly surprised.

Installation was pretty straight forward.  Clean with supplied lens cloth and carefully drop into place.  Done.  So far I have to say the screen is every bit as responsive as ever, there are zero bubbles or imperfections and so far it seems to pick up less dirt and finger “grease” than the screen itself did.  I wish it were just a millimeter or so bigger in both dimensions than it is… there is a very fine line around the screen that is visible if you know what to look for but is probably not noticeable to anyone else.  That aside though, I have to say it is working as advertised and if it keeps all those microfine scratches off my screen that my DX18 seemed to accumulate regularly (and it wasn’t even touchscreen) than I will be ecstatic.

At around the $600 mark, I think there is a lot to like in this radio.  And yes, I am a bit of a Spektrum fan for which I make no apologies.  I have worked with several other brands like Futaba, Hitec, Airtronics, Multiplex , Graupner and a couple others I can’t even recall.  All of them have some interesting features and strengths but it is hard to beat the Spektrum value for the dollar, excellent support and good balance of feature set with ease of programming.  The iX12 leans toward the more complex end of their line of radios so it may not be the ultimate answer for those who are not smartphone savvy or that are just happy with their DX7s or 9 or whatever but I think I’m going to enjoy it for quite some time.  At least until the iX12 Gen 2… or iX18 or whatever hits the market next! 


Graupner MZ-24 Radio — What???

My flying buddy Kelly, who I’m pretty sure considers me his personal “RC Aircraft Mechanic and Radio Setup Technician”… decided some time ago that he wanted to get a new radio system for his RC needs.  I know he has had good experiences with his Graupner charger and is a big fan of German engineering in general and so had high hopes when he ordered his new radio system.  He even talked to me first to insure that I was up for learning a new system and I said yes….

I have programmed many RC radio systems over the past 15 years or so. Airtronics RD6000, RD8000, Hitec Prism 7, Futaba 9CAP, Multiplex EVO 9, JR9303 and Spektrum DX8 and DX18 are all transmitters that I’ve spent time programming.  I’ve spent significant time and effort setting up multiple aircraft from trainers to multi-engines and delta wings to 3D aerobats on these radios and now I can add the Graupner MZ-24 to that list… or at least I’m trying!

Some random thoughts on my experience so far.

The MZ-24 is NOT a 24 channel radio.  For EVERY other radio in my list above you could probably correctly guess the number of channels by picking out the number in the radio name… but not the Graupner.  For some reason the number of channels you can control is 12… you can now decode that the MZ-18 is a 9 channel system, maybe?.  Kelly wasn’t fooled… he’s definitely a guy to research his purchases but I was fooled for a minute or two.

What Kelly thought was a German radio was apparently designed and built in South Korea?  Now that’s not a bad thing in my book… I’m pretty sure that more than half of the electronics in my home were designed and built there and I wouldn’t keep buying them if I didn’t think they were great products….but this radio…. maybe not my favorite effort from our friends in South Korea.

Setting up the flap system on this radio has been a multi-week odyssey which has ended in…. success… but only after completely abandoning the built in flap system functionality!  Apparently, setting up the flap system to do a simple 3 position flap setting with elevator mix is completely beyond my ability using this radio if I try to use the built in flap system.  Even after a few exchanges on the phone and via email with Graupner support I could not reliably make the flaps worked as I wished.  Setting the end points of the flap function is apparently impossible, and simple reversing of the function and strange things like changes in speed through the travel of the flaps are a couple of the  challenges I faced when trying to use the flap system.  Take my advice and just leave that function alone.  Just assign the channel, set the endpoints and sub-trim to establish the motion you want.  Slow the servo with the servo speed function and then build your own mix for elevator or whatever else you need.

Programming the telemetry system on this radio is… just odd.  While most other functions are configured in a somewhat intuitive method… when you get into the telemetry system you are confronted with screens of text that look like they are something from a 1970s computer application… i.e. from the days when computers didn’t yet have a mouse attached or a graphical interface.  Gone are all the pretty colors, graphs and symbols.  Absent are any understandable directions… at least for the simple voltage monitor we wanted to use.  Even the list of “alarms” are just labeled with numbers.  What each number represents is cataloged where?  Imagine how easy it could be to program a telemetry system if you a full touch screen color screen with audio prompts available…  Oh, that describes the Graupner radio!!  Unfortunately what we get is text only…  Did the graphical interface team all quit mid-project?

The range of receivers available, reasonable pricing as I recall and apparently solid build quality… even the various ports and options available… All would give the impression of a high quality, easy to use, good value, complete RC system.  To bad that it seems this product never got “finished”… or at least that is how it seems.

We are going to continue to work with this system and just see how it goes… at least until or unless we run into actual RF issues, which I don’t expect.  Here’s hoping Graupner does some more development and sorts out the oddities in the user interface.  The potential is certainly there.

For my part, I think I’ll stick with my Spektrum DX18.  I think both it and the DX9 are great radios that do about anything you’d want and who’s interface is far superior to the Graupner… even without a touch or color screen!


Throttle lock/Kill Switch programming on the DX8

A couple years ago I was taxiing back toward the pits with one of my smaller gas powered planes and had stopped to observer another flyer doing a nice touch and go… My plane was sitting by my feet at a sedate idle during this distraction.  When I turned back, I returned my left hand to my radio and inadvertently slid the throttle stick to full!!  Luckily I was pointed at the pit chain link fence 6 feet away with no other obstructions… like people… so as I grabbed the stick and returned the throttle to idle the plane made a dash for the fence and quit as a result of the impact and the prop breaking into several pieces.  It did no real harm to anything except the prop and my pride… but it woke me up and from then on I have been much more attentive to my models while they are running.  When I am idleing, my thumb is hooked across the top of the throttle stick so that it cannot easily be moved upward.  As well, I now have a kill switch on every fuel powered airplane and it is always in the same position on the radio so I don’t have to hunt for it!  With gas planes I have a mechanism hooked into the ignition circuit that kills power to the ignition.  Depending on the type of engine and ignition system it may work a bit differently but each disables the ignition which kills a gas motor immediately.

With the advent of more electrics in my fleet this became even more problematic.  Electrics, once the battery is connected, should be considered to be “running” in all cases and therefore treated with the respect that would be due any idling engine.  Since you can forget the battery is plugged in at times, I try to be especially careful to restrain my electric powered aircraft whenever I’m not holding on to them and a battery is installed.  I have also setup a throttle cut switch that limits the throttle channel output to zero or as close as possible.  In some radios this is simpler than others.  In my Spektrum DX-8 there are two ways to accomplish this… maybe more… but I’ll show one of them here that I use most.  (I believe the 7s, 9 and 18 all do it similarly)

Note: You can do all of the following without the plane even being present and certainly don’t want to play with this with the plane powered up!  I highly recommend you test after you finish however with the plane well restrained or the prop removed.

First, the DX-8 has a throttle cut option in the setup menu.  If you go into that menu and change the inhibit to a switch label (I tend to use Gear0 as I’ll show below) you get a screen that looks like this.

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You’ll notice that the switch is set to Gear0 (that’s a zero).  I use this setting as I tend to setup my radio so that starting point for all airplanes when I fuel up or attach a battery is with all switches pushed away from me.  It really doesn’t matter which way you do it.  I’ve worked with computers and electronics so long and the way I was taught logic you generally consider 0 to be off and 1 to be on…. I guess position 2 is “really on” in the case of a 3 position switch!

With my radio set this way the throttle is locked so it cannot inadvertently start up without moving both the throttle stick and moving the gear switch out of its starting “safe” position.  The other thing you may notice is that the position reads 30%.  I played with this and came upon this setting by trial and error.  I believe this has to be done because of two factors.  First, the designers created this for (I believe) primarily fuel powered aircraft where the stop/kill position is significantly different from the idle/standard starting position.  In an electric aircraft you generally don’t want an “idle” with the prop moving when you pull back to the lowest position on your stick.  You want a full stop.  Second, most speed controllers in my experience will look at the throttle setting on power up (as long as it’s at least somewhere near one end of travel or the other) to be the zero/stop point.  That’s fine until you combine with point 1.

So imagine you plug in the battery with the throttle 30% lower than “idle”… which is what the throttle position would be if you left that setting at zero and had the switch pushed forward/off when you plugged it in.  All seems fine… Your speed controller makes its little tunes and if you move the throttle stick nothing happens but your servos are energized (this may vary by manufacturer of the speed control).  Great, you are ready to taxi and you flip the switch to the armed/on position and immediately the prop spins to a “high idle” setting!!!  That’s not convenient, nor especially safe.  This is because with the kill switch in the forward/off position the throttle was at a point 30% or so below the idle point and when you plugged in the controller reset that to be “zero”.  By testing I have found 30% to be about the right point to avoid this issue.  Now the kill switch doesn’t really change the position of the throttle at all and acts more like a throttle hold then a cut.  Ideal for what we want when dealing with electrics.

There are other ways and other radios do it differently.  On my DX-18 which I fly more than anything else I use the F switch instead of gear because I use the gear for other things… like retractable gears!  But whichever switch you use, I suggest you keep it consistent.  This way your routine on each plane is the same at least as regards to a safe “startup” and also because occasionally you may want to hit it in a hurry and not having to think about which switch it is can make a big difference in response time.

I’ll try to post on a different method in the near future.  Hope this is helpful.  Fly safe!


ElectroDynamics Multi-Connex… The answer for the Carbon-Z T-28 and many others.

After a few trips to the field with my buddy Kelly and his new Carbon Z T-28 we quickly became aware that assembly was a bit painful because of the number of servo wires that must be connected when attaching the wing and the shortness of the wires supplied in the T-28.  The length of the wires can be easily fixed but just connecting the 6 wires correctly and reliably time after time seemed an unnecessary annoyance to get to what the Carbon-Z does great… fly!

Another club member pointed out some multi-pin connectors often used in jets and after some quick searches we located the ElectroDynamics OneClik Multi-Connex.  Made for 2,3,4 and 5 servos connections these seemed to fit the bill so we placed an order.  Very shortly (even though we chose the most economical shipping method) we had two of these packs on the bench.

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Here’s the interior of the T-28 before we applied the OneClik solution.

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and likewise here is the wing root before the installation.2015-09-25 10.33.54

Here is the wing root after just sorting out the wires and plugging them in (in alphabetical order just for ease of remembering!) to the new One-Clik wiring harness.

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Similarly the interior of the fuselage (with a little wire combing to really clean things up as well).

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I applied a bit of combing to the wing wires as well and then with only two connectors to feed through the bottom of the fuselage it is suddenly very easy to assemble the T-28!  A  bit of Velcro (just a 1/4″ square of so on the connector and a small strip on the sidewalls) makes a nice “keeper” for the new connectors and completes the transformation!

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Admittedly, it helps that the T28 uses all “Y” connectors so there is no right or wrong for left or right sides so you can’t connect it wrong but for those that don’t… at least you’d only have to label right and left!!

The product has a nice snug fit, a great positive click connection and appears to be of a very high quality.  The pricing seems very reasonable and my only regret is that I didn’t order some of these for my Mustang!  Oh well, even with shipping these seem to be a bargain.

Since installing these, we have made a couple trips to the field and unlike previous trips, the setup time is less and we have not had a miss-connect (pretty much impossible now).  In the past this was a tedious task which has occasionally resulted in having to pull the wing and find an errant wire.  I think that is likely in the past.

This system will likely become one of my go to upgrades for all future multi-servo wing aircraft.  The ease of use and added security of the connection is a huge plus in my opinion and I highly recommend you give these a shot especially in those larger and more complicated craft like warbirds and the like with flaps, lights, and etc…

Very odd failure of a Spektrum RC AR9000

My flying buddy Kelly has one of the Top Flite P-40 Giant Scale ARFs.  It’s a beautiful plane and if you are interested in this size and type of aircraft (50cc giant scale warbirds) I encourage you to check it out.  It is a well built and good flying aircraft that shows that the designer has learned from the earlier models in the line and made some important upgrades that make this airplane fly nicely but also hold up well to a few “imperfect” landings and hang together.

Last year, he came to the field and while assembling the plane as usual noticed something disconcerting.  After powering up the radio system with the plane fully assembled and ready for flight the flaps began jumping around in a random manor!!  After dis-assembly, some testing and no flight whatsoever that day… (sometimes you have to wonder why we do it) we determined that the flap channel (6) was always affected, regardless of which servo we plugged into it.  Off the receiver went to Spektrum for repair.  They did whatever it is they do and pronounced it good to go with no problem found.  They also “tossed” in at no charge a “software” upgrade while they had the receiver which was nice.

When we reinstalled, we did not see the issue again until… you guessed it, another day at the field and another day with no flying!!  Now, I don’t blame Spektrum for missing the issue with this receiver as they did not have one key bit of information.  What we discovered this time is that channel 6 only has an issue when channel 5 (landing gear) is at a particular extreme.  In this case, down.  I have further determined that it is the receiver and not the radio at fault as we removed the receiver and bound it to my DX-8 and saw the same issue.  Here it is with just the receiver under test, a 2S A123 as a power source and my DX-8.  I also show a meter to display the voltage to the receiver so there’s no question that the power supply is out of range.

Check out the video here: AR9000 Video

Apologies for the focus issues, but you’ll see that the servo attached to AUX1 remains perfectly still until I flip the gear channel and then the “twitching” begins.  I show this not to pick on Spektrum but to simply display a very strange failure mode I have never seen before and spark some thought processes that might save an airplane or two.  I

When you do your ground check, do you check with the various channels at full throw? With the gear up and down?  etc…  You may want to occasionally go through a “full throw” check if you can.  This may require someone holding the airplane or a stand if your setup involves retracts.  I think I am going to start doing an occasional control surface check with other surfaces at extremes.

I’m convinced that this would have meant a crashed P-40 if the problem had only shown up with gear up… i.e.  Nothing at all would have been wrong until the plane was airborne and he hit that switch to raise the gear.  Having the flaps randomly jumping back and forth in mid flight and with no clue as to why the plane started wildly pitching up and down would have likely been catastrophic.  It may be a very rare occurrence but you can be sure I am going to do the most thorough surface movement checks I can devise on all my aircraft in the near future.

I’ll add commentary to this post or perhaps do a “part 2” when I get this back to Spektrum and get their feedback.  For now the P-40 is ready to fly again with a different Spektrum receiver.

Blade Nano QX – Radio configuration

I’ve had the Nano for a few days now… maybe a dozen flights and I’m enjoying it very much.  Straight out of the box and with the radio configured per the instructions (Using my DX18) it is a nice flying aircraft.  However… there’s always room for improvement, right?

So here is what I’ve done to program my DX18 to help the little quad fly even better.  Here’s my list of “wants” that I came up with:

  • First of all, I wanted a throttle cut.  I consider throttle cut to be a necessary safety feature on any aircraft and on electrics especially.
  • Obviously I need a timer.  The flashing light on the Nano that signals a low battery has so far been unnoticeable for me.
  • Finally, I wanted to institute Expo and End Point adjustments in concert with the change from Stability mode and Agility mode.

With that in mind I started to do some programming on my DX18.  As I thought about what I needed, it hit me that what I really wanted was to use “flight modes”.  With the FM feature, a single switch or combination of switches can change multiple settings including end points, dual rates, expo settings and more.  I have never had a real need for FM, though in some cases it might be equivalent to or better than what I do now, but this seemed the perfect fit.  I wouldn’t want to enter the agility mode without also dropping my rates down and adding some expo and doing that all on one switch seemed ideal.  I knew there was some reason I bought this expensive radio!

The throttle cut function was easily added as was a timer… very standard and easy to do stuff.  But the next part got a bit more difficult.  The mode change (Stability or Agility) on the Nano is set to operate off of a temporary switch… in this case button “I” which is often used as the trainer switch on most radios.  I now wanted this to move to one of the 3 position toggles so that it would happen in concert with my flight mode changes.  It isn’t difficult to reassign this function (in this cast AUX1/channel 6) but when I did that I quickly realized that this was not going to work as intended.  I had thought I would have 3 flight modes.  FM1 would be stability mode with full throws and a little Expo (maybe 30%) thrown in to help me be smoother on the controls.  FM2 would be agile mode with moderate throws and a similar amount of Expo with FM3 being “crazy 3D guy” mode with full tilt throws and a much greater expo setting (maybe 70%) in order to keep things from being to touchy.  Not sure I’ll ever need that mode and maybe I’ll switch this around later to 2 Stability modes and only 1 Agile mode option but this is my desired starting point.  After adding in the “Quad” graphic the main screen shows the modes as seen here.

Here’s FM1 – Named Stability Mode


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And FM2 – Agility Mode I



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And finally FM3 – Agility Mode 2

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That all looks good but after moving the AUX1 channel to a three way toggle, a quick on-bench test immediately brought a problem to light.  The Nano wants to see a temporary Off-On-Off type of signal to change from Stability to Agile and vice versa.  Just going Off-On didn’t do anything until you came back to Off.  Imagine toggling the switch from 0 to 1 (no change in Stability mode but more throws) or moving on to 2 with lots of throw and expo but still in Stability mode… no big issue yet.  But, then going back to 0 and suddenly you’re in Agility mode but with full throws and low Expo… yikes!  For a bit I thought I was stuck… but then the DX18 came to the rescue.

The DX18 has something called a sequencer.  With the flip of single switch you can have a series of events occur.  In this case I setup the sequencer so that going from 0 to 1 (or 1 to 0) caused the Aux1 channel to move to full (step 1) and then back to start (step 2) with a delay of about a half second in each direction.  This sent the correct sequence of events just like hitting a temporary switch.  Moving from position 1 to 2 does not have an associated sequence as I’m already in Agile mode after I move from 0 to 1.  Nifty!  The only catch here is that you have to start with the switch in the correct position.  That’s not a big problem as I have a habit of having all switches pushed away from me when I power up my radio.  I found a way to help with that issue as well though.  More on that a bit later.

With that solved (it’s easy to test for this on the bench as the Nano changes its LED from blue to red when you enter Agility mode) I moved on to setting up my throws (End Points and Dual Rates) as well as my Expo settings for each mode.  With that all accomplished I did a quick trial flight and so far everything is working as planned.  Of course nothing is perfect and I started thinking that I really wanted to insure I powered up the radio in flight mode 1 and with the throttle cut engaged.

This got me to looking at another underutilized (at least by me) feature of my DX18 and that is the preflight checklist.  I immediately found this feature to be quite simple to use.  I have to say I sure wish I could edit the checklist descriptions, but I found two that are close enough that reading them will get me to thinking about these two important switch settings.  My Mode Switch is using a switch that I often use for flaps on other aircraft so the “Flap Position” checklist item works for that and the “Thro. Trim Position” gets me thinking about throttle enough to remind me to check the throttle cut switch.  Of course these check box items don’t actually check the position of those switches for you, but you can (and I did) set the radio so that it will not start sending RF until I check the boxes, and you have to do it before each flight (assuming you turned off the radio or went to another model memory in between).  At least it gives me one more chance to get it right before taking control of the Nano!  Here is the setup screen for that feature.

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And Here is what the preflight screen looks like on power up.

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Lastly another thought occurred and I went into the warning screen and made it so my radio would alarm if my throttle wasn’t at idle (or at least nearly so) and/or I wasn’t in FM1 when I start up the radio.  That’s even more foolproof than the checklist!  Here is the setting for that:

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I think this gets me “in the ballpark” as far as radio setup goes.  I’ll undoubtedly adjust my expo and dual rate settings but those are minor tweaks.  With this configuration I have checked off all of my wish list and gone a bit further on safety and initial start up settings.  So far after a couple more test flights after all this was configured I am well pleased.


Only 0ne more issue to tackle… that of visibility.  I have some ideas on that and I’ll post on that soon.  Happy hovering!