Losing my confidence in Spektrum

[airmail wf]

There is nothing wrong withn FM. A lot of good deals out there at swap meets.

[NJSwede]

Originally Posted by hayofstacks

I have never used expo, I've never used dual rates. The only thing I have used is the timer, and I almost always forget to set it. I did play with flaps and mixing, but I have decided its more of a toy then useful on anything I fly. Then when you factor in a $60 receiver for one of my $25 to $100 planes, there is no reward there. I can buy a plane and a half for the price of two receivers. An fm one runs $10 all day long and I have crystals.

Fly whatever brand you feel comfortable with. However, I'd like to say one thing: When I started out about 18 months ago, I never thought I would need things like expo and mixes. Now and can't live without it. I don't know how long you've been flying, but when you pass a certain point in your "career", you're simply going to need those features, or your progress as a pilot will be hampered.

You don't have to go crazy to get a radio with good features. I spent a very small sum on a used DX7 that I still use. It has everything I need now and will probably last me another year or two before I have to upgrade. As for receivers, I buy the OrangeRx about 5 at a time for $6 each and use them in anything cheap and simple and use AR6115e or AR600 in things I care about. Very cost effective and works like a charm. You can probably get a similar deal if you want to go the Futaba route. The point I'm making is just that you'll be sorry if you buy a system lacking advanced features just because you don't need it right now.

IMHO, YMMV and so on...

[dahawk]

I got my Futaba 6EX for $50.00 and bottle of wine. Use Frysky, Orange, and Corona Rx's from HK( 1/3 price) with no issues.

[spad]

Some would suggest you paid too much; however, I wouldn't.

[dahawk]

It was a cheap bottle of wine !

[kyleservicetech]

Originally Posted by dahawk

Airmail,

A 1lb plane flying at 100mph has the same force impact as a 2lb plane flying at 50mph.

Minor update:
http://www.csgnetwork.com/kineticenergycalc.html

The kinetic energy of a moving object is related to its mass times the velocity squared. (KE=1/2mv^2)

So, running the numbers, a 100 Mph 1 pound model has double the kinetic energy of a 2 pound 50 Mph model.

Which is why a real bad landing at 75 Mph on a gasser model will do a lot of damage. The same landing at 150 MPH of a wet turbine model won't leave much left. And, a 30 Mph bad landing of a foamie, and you've got a decent chance of picking up the model and flying it again.

[airmail wf]

How about 75mph foamie into a wall?

[kyleservicetech]

Originally Posted by airmail wf

How about 75mph foamie into a wall?

LOLOL

Was that personal experience? But did your receiver survive

[airmail wf]

Check it out.

Assassin vs Brick Wall 3-12

[kyleservicetech]

Originally Posted by airmail wf

Check it out.

Assassin vs Brick Wall 3-12

Wow, that would be a good trainer! Sure can't beat the price!!!

[hayofstacks]

Well, the fm radio has been a lot more reliable, and my fm radio was free. I have about 50 old fm radio's in our garage(slight overstatement). Saw a lot of people do a lot of things before the days of dual rates, servo range adjustments, you name it. I also don't fly at a real flying feild, and even if I did, I doubt I will ever see anyone else fly fm either. Plus if I need to "upgrade", I can just buy a module that will work with any of our futaba fm computer radio's.

[Scott the plane man]

Originally Posted by e-pilot

My giant scale Cessna 182. It sure was a beautiful aircraft. Now it's in a bag, and I'm pretty sure I can thank Spektrum. This is the second plane I've lost on Spektrum.

I have a DX6i, and when I first got it, I loved it. I was a really big Spektrum fan for a long time. Now I'm losing my confidence.

The first was a small L-39. Pulling out of a shallow dive there was no reponse. I could hear the edf unit still running at my commanded power setting, but there was simply no response to stick inputs. Flew itself at high speed into a bush ripping it to pieces, but the fusealage was still intact except for the nose wich was ripped out due the battery continuing flight after the aircraft had stopped. After retrieval, the radio system worked fine. Totally unexplainable loss of control. Rx was a 6110e (before DSMX). Since I was one of only two people airborne, and the other guy was on 72mHz, I doubt DSMX would have made any difference. This happened right in front of me at only 100ft seperation between me and the aircraft. It was not a transmitter antenna orientation issue. I learned that lesson long ago. I always fly with my transmitter antenna pointed straight up overhead.

My giant 182 was purpose built for reliability. I invested a huge amount of money and took every precaution I could afford. I used an AR6210-X with satellite. (I understand that using an X receiver with a non-X transmitter means you are still flying regular old DSM2.) Antennas were oriented in 90 degree offset planes and were placed against the fuse side and bottom so only a 1/16 sheet of balsa and the monokote separated the antennas from the signal.. I used a 6V 2200mAh Nimh receiver battery to not rely on the BEC of the ESC in case the ESC fried. The receiver battery was charged up the night before the flight and showed 7.02V after a 6 hour .2mAh trickle. (I had done a 16 hr on it the previous week and only flew the plane twice after that charge.) The receiver was 2 feet away from the ESC and 1 foot away from the closest battery wire. Every extension wire coupling was tested with an ohmmeter after using CA to make sure no separation could possibly occur. The servos were not high current draw. Hitec HS-485HB. (It was, after all, only a Cessna and not a 3D monster so it didn't need anything more). The on/off/charge switch was tested before installation for any voltage drop across the contacts and only extremely minimal amounts could be detected, when I could detect any at all. Wire guage was ample to carry the current. Receiver was checked before and after each flight (all 5 I got to make) for blinkies with no indications of a problem.

Until last weekend. Airborne for 2 minutes and turning base for a touch and go, stick inputs became meaningless. The aircraft was flying itself, and as we all know, that is a bad thing. I prayed to regain control but could only watch as it rolled over and augered in. Hard. There was nothing left of the receiver battery to test, but I know it was in very good shape and could have easily supported 2 or 3 flights that day if not 10 were I a reckless builder and pilot. The receiver, however, in the rear cargo area, survived completely with all its connections perfectly intact including the one to the shredded end which used to be soldered onto the receiver battery. Bench testing today showed the receiver to be working perfectly. All servos tested fine as well eliminating a stuck or shorted servo that would draw huge current. Again, a totally unexplainable loss of control.

(BTW, I'm impressed with the Hitec HS-485HB. After a total loss high speed impact crash, not one of them even popped a tooth much less needed rebuilding with a new gearset.)

So I'm losing my confidence in Spektrum. Your pre-flight check should NOT have to contain a step wherein you remind yourself that even though you do everything right, there's still a 1/2% chance that you'll simply be disconnected from your aircraft and have to watch it be destroyed.

i have never seen anything like it i thought spectrum was good!!
Is this true??

[Turner]

It's true that RC planes crash due to a multitude of problems. If people have Spektrum gear it is fashionable, to some, to blame the gear. If the gear is Futaba or something else, well there must be some other explanation. I and many others use Spektrum gear with no problems.

[dahawk]

Originally Posted by Turner

It's true that RC planes crash due to a multitude of problems. If people have Spektrum gear it is fashionable, to some, to blame the gear. If the gear is Futaba or something else, well there must be some other explanation. I and many others use Spektrum gear with no problems.

Turner,

I could not agree with you more. Though I'm a Futaba guy, the majority of the guys in our club are Spektrum users and one would be hard pressed to tell them that their computer radio is inferior in any way to anything. People get emotional about their radios.

I think they're all good. JR, Spektrum,Hitec,Frysky,Airtronics, etc. You name it. They all have their quirks. Sometimes it's like showing up at a party and everyone is speaking a different language. At least that's how it is between Futaba and Spektrum.

It's what floats your boat...

-Hawk

[hayofstacks]

All I have to say, I had a full range with receiver in my alpha 450 sport. I was having weird glitches and range problems (less then 200'). My servo's were jittering, and my throttle was slow to respond, or didn't at all. Had several losing bind problems before takeoff. Going to a $10 receiver fixed all of those problems, but then it locked up while I was doing touch and goes. Only one resulted in a crash, and it ripped out my landing gear block. What scared me the most, was the plane turning itself into the pits while I had no control. Imagine if it locked up under full throttle?just really lucky I was low with no throttle. My plane is fairly light, but my dad has flown his 5-6lb gas jobs on spectrum too. That could really, really hurt someone. Where an fm radio has never even glitched.

If you crash planes everyday and blame the radio, good for you. I don't. I also don't have the money to buy a new plane when my spectrum gear does fail in a worse situation. It was a waste of $200 for my dx6i, $50 for a receiver, couple of re chargeables and a couple $10 generic ones.

Sticll have all of the fm gear that I learned to fly on, and never had a problem.

[solentlife]

as with hayofstacks .... my FM gear never let me down ... I can also say that my JR Propo 8ch from the 1980's has a feel that I cannot find in any current Tx I've handled. The Jr Propo tensioning and stick adjustment was far better ...........

The weight is more but it feels solid in the hands ............. separate snap roll buttons, throttle + rudder link ... all sorts of mixes available via pots / dip switches .... it was a sophisticated pre-computer radio ....

My 9x today has far more capability than average flyer ever needs .... I've never had a 'brownout' that I know of ... I've had some strange crsahes that initially felt as though model lost control - but once I've sat down and considered incident - I realise that it was me or wind fluke or other but not radio brownout.
I would suspect that many of the so-called BO's with most radios are really other causes ....

[kyleservicetech]

Originally Posted by Scott the plane man

i have never seen anything like it i thought spectrum was good!!
Is this true??

The club I belong to has pretty much gone over to Spektrum/JR 2.4 Ghz radio systems. One person does have a Futaba system. Somewhere there was a survey that showed that Spektrum/JR has the majority of model RC control sales in the USA.

After our club members have accumulated countless flights with the Spektrum and JR 2.4 Ghz radio systems over the past three or four years, I'm not aware of a single case where a loss of control was traced to the Spektrum/JR radio systems. One crash with loss of elevator control involved a new Spektrum DX7, AR7000 receiver. That was quickly traced to a new Hitec elevator servo that just quit after about 5 minutes of flight time.

I did run across a club member that had just flown a wet turbine model with a JR 2.4 Ghz radio, and had a very good flight. On landing I found the receiver battery in that turbine model was a single 2700 Mah 5 cell "AA" type Nih battery pack. That model had some 7 or 8 high current servos in it. He was lucky he didn't loose the model due to voltage sag on that receiver battery.

Another member had a top of the line Futaba transmitter and receiver in his wet turbine model. The transmitter shut itself off during flight, resulting in total loss of the turbine model. That transmitter did it again in my workshop. (Futaba found nothing wrong with it) This modeler switched over to a top of the line JR radio system, and has had zero problems with it over the past three years.

Now, our club is mostly Spektrum/JR equipment that has been working very well. And you can very likely find other clubs where the Futaba radios have been working very well, and they don't like Spektrum/JR equipment. Spektrum now has the DSMX system, that is a subject that could use its own thread as to how it works.

Nice thing about the Spektrum/JR systems is their model match feature that absolutely prevents taking off with the wrong model programmed in your transmitter. I've seen several crashes due to this issue on the 72 Mhz radios over the past year or so. One of them was an expensive gasser model.

On this type of thread its always a good idea to see how many other readers have had similar problems with the Spektrum radios. (Or any other radio brands for that matter.) Before retiring, it was common to find that 90% of our customer complaints with our $$$$ high voltage high current circuit breakers were by 10% of our customers.

[Turner]

Once you see the Horizon Hobby family do one of there big demonstrations at SEFF or anywhere else it is pretty reassuring that they have full confidence in the entire range of Spektrum products. It seems certain they are using nothing but off the shelf products without any problems.

[e-pilot]

I'm glad some of you guys have had good luck with Spektrum - so did I for years. Probably so did all the guys bringing their planes home in bags from SEFF this year... Spektrum is great if you want to limit yourself to parkflyer foamies. I'm beyond that, and I'm beyond Spektrum. It served me well as an entry level radio and I thank Horizon Hobby and the Spektrum engineers for that. I've just completed an exhaustive investigation of all the major 2.4gHz band products and the methodology and reasoning of the engineers (and accountants) who designed them, the 2.4 gHz band in general, and a study of RF communication, design, engineering and interference tolerance. As a result, I am retiring my Spektrum equipment.

http://www.rcgroups.com/forums/showthread.php?t=1644070

(Get past the first post where the guy was flying Orange receivers... Read the whole thread)

[Turner]

Originally Posted by e-pilot

...I've just completed an exhaustive investigation of all the major 2.4gHz band products and the methodology and reasoning of the engineers (and accountants) who designed them, the 2.4 gHz band in general, and a study of RF communication, design, engineering and interference tolerance....

Wow, really? Let's see some data.

[kyleservicetech]

Originally Posted by e-pilot

I'm glad some of you guys have had good luck with Spektrum - so did I for years. Probably so did all the guys bringing their planes home in bags from SEFF this year... Spektrum is great if you want to limit yourself to parkflyer foamies. I'm beyond that, and I'm beyond Spektrum. It served me well as an entry level radio and I thank Horizon Hobby and the Spektrum engineers for that. I've just completed an exhaustive investigation of all the major 2.4gHz band products and the methodology and reasoning of the engineers (and accountants) who designed them, the 2.4 gHz band in general, and a study of RF communication, design, engineering and interference tolerance. As a result, I am retiring my Spektrum equipment.

http://www.rcgroups.com/forums/showthread.php?t=1644070

(Get past the first post where the guy was flying Orange receivers... Read the whole thread)

Yup
Read the entire thread. Seems that most of the radios in use were the Spektrum/JR systems. That said, might be a good idea to to to the DSMX or similar systems when flying at places like SEFF. If you've got over 100 transmitters all turned on at the same time on 2.4 Ghz, that is really saturating the 2.4 Ghz band.

[kyleservicetech]

Originally Posted by Turner

Wow, really? Let's see some data.

Agreed:

That would really be useful information.

More than a few of the lockouts at SEFF appear to have been of the 5 second period of time. That could also be an issue with those linear voltage regulators on some of the ESC's. I've checked the recovery time after loss of signal or applied low voltage brown out of my Spektrum AR7000 receivers on my Tektronix 2236 oscilloscope. Recovery was much less than one second. All of my Spektrum receivers had the latest software installed several years ago.

Take a look:
http://www.wattflyer.com/forums/showthread.php?t=63779

[NJSwede]

IMHO, this post says it all:

http://www.rcgroups.com/forums/showp...0&postcount=10

People put junk components in their plane, it fails, and they almost always blame the radio system when there are a lot weaker links in the chain. I use a lot of cheap stuff in some of my planes myself, but I'm fully aware that my DX7 is by far the highest quality component, so if I have a problem, that won't be the first place I'd start troubleshooting. More likely the last.

[kyleservicetech]

Originally Posted by NJSwede

IMHO, this post says it all:

http://www.rcgroups.com/forums/showp...0&postcount=10

People put junk components in their plane, it fails, and they almost always blame the radio system when there are a lot weaker links in the chain. I use a lot of cheap stuff in some of my planes myself, but I'm fully aware that my DX7 is by far the highest quality component, so if I have a problem, that won't be the first place I'd start troubleshooting. More likely the last.

Yeah
Last year I caught a club member that had just flown a $$$$ wet turbine model with a DX8 transmitter and top of the line receiver. Took a look at what he had inside his model, and spotted a 5 cell "AA" type 2700 Mah Nih receiver battery. No backup battery. This was on a model worth well north of $4000 that had some 7 or 8 high current servos in it.

I tested his battery pack on my oscilloscope, that battery pack dropped below 3.5 Volts DC in a fraction of a second when all servos were being operated. The Spektrum receivers reboot at about 3.2 Volts DC.

He was lucky to have not lost that turbine model. He's since gone to LiFe or A123 type receiver batteries. Those type batteries will melt the battery wires before the battery voltage sags at very high currents. After doing that, those batteries will win. (Don't ask how I know!)

[NJSwede]

Originally Posted by kyleservicetech

Those type batteries will melt the battery wires before the battery voltage sags at very high currents. After doing that, those batteries will win. (Don't ask how I know!)

I don't think I have to...