rclement

My Feedback: (1)

I had a total loss of control yesterday with a plane that only had 3 flights on it. I took off, got up to about 40-50 ft and went inverted while banking to the left and about 1/3 throttle. Then while trying to bring the plane back to right side up I noticed that I didn't have any control of the ailerons or anything else. Nothing, no signal to the plane. As mentioned in the title the TX is a Spektrum DX 7 that I have been using for about 1 1/2 years, the AR6200 was used in another plane without any problems. I'm at a loss as to what happened. I don't know if the RX tried to restart or recycle as I have read on some other threads. ?? I don't know if I need to send my radio gear back to Spektrum. ?? Anyone have any ideas? This was a 7lb plane with an OS 120 AX and could have been a serious problem if it hit in the wrong place. I don't know if can trust the RX in another plane or not. ?

fizzwater2

My Feedback: (61)

If you don't trust it, send it to Horizon for a checkup. Better safe than sorry.

BuschBarber

My Feedback: (2)

Have you tried doing a Range Check using the procedure outlined in the DX7 manual. The DX7 has a very large Bind Button on the back of the TX. I have actually leaned the Tx back against the edge of a flight stand and the weight of the Tx inadvertently depressed the Bind Button. When I turned on the Tx, I had no communication with the Rx and I had to ReBind with the Rx, again. There was a thread where someone had attached something to the back of his DX7 Tx and it depressed the Bind Button, while flying, thus cutting the Transmit Power in half and losing Range. It was like collapsing the Antenna on a 72Mhz Tx.

Older Spektrum Rx's had Firmware that took more than several seconds to Reset after a Brownout. The older Rx's can be sent in to have newer Firmware installed. The newer Firmware allows the Rx to ReLink much faster.

rclement

My Feedback: (1)

I can try to do a range check with it but it seems pointless at this point. I mean that I can range check it after the crash but if it doesn't check out right I won't know if it's from the crash or if it was that way to begin with. I just got off the phone with Spektrum and the gentleman said that it could have gotten a brown out or the RX battery may not have charged all the way and it got a false peak from the charger. He mentioned that I would probably want to send in the TX and RX for a check up. He also said that if it's the older version of firmware in the TX that it could take 3-5 seconds to reset if it got a low voltage signal in the system (brownout).
Either way I'm not happy about it. I just lost $200 bucks and could have killed somebody. I never had any problems like this with a 72 mhz radio and never lost one.

electricpete

What battery were you using? How old was it?Did you do range check at beginning of day.

Pete

rclement

My Feedback: (1)

I was using a Hydrimax 2000, the battery is fairly new, no I didn't range check at the begining of the day.

BuschBarber

My Feedback: (2)

It is always painful to lose an aircraft, especially from a radio failure that you did not anticipate. I had been using Spektrum Rx's before the Brown Out issue was discovered. I had been using 5cell NiMh or 2cell LiPo Rx batteries and I have never encountered the problem. I bought an H9 Volt/Amp Meter so I could measure the current draw of an individual servo or the entire system, where All servos were Stalled. I made sure my battery capacity was more than the system required. The Brownouts happened when a unusually heavy load on the batteries caused a Voltage Drop that caused the system to Reset. I sent my Rx's in to get the newer Firmware so the Reset Time was very short. No problems!!

I like A123 or LiPo Rx batteries because they can handle the load and recharge Fast. No more NiMh for me!!!

rclement

My Feedback: (1)

Thanks for the info and I'm sorry I haven't gotten back to this sooner. I got the impression from Spektrum that the upgrade was in the TX, I guess I got confused but found out it's in the RX. I also heard too from a guy at the field that it's with the AR 7000. Is it the 7000 or the 6200 or both?

Zeeb

My Feedback: (41)

The Quick Connect firmware update is for the rx's and affected ALL of them manufactured before about Feb. '08 IIRC ('could of been '07 as my memory isn't as good as it used to be and it's been awhile since that change.... lol). All of the rx's manufactured after that came with the Quick Connect firmware. The first version did not have the rx flashing light indication that a brownout had occured like the current version of the firmware. The simple test is to turn on and link the rx with the tx, turn off the rx and then turn it back on. It should relink in less than 1/2 second and the lights on the rx's should flash, not as fast as you see when binding but in the case of rx's with satellites all of them should respond the same way. Older satellite rx's need the upgrade as well.

As for your battery issue; several years back the EPA mandated a change in the chemistry of NiMH battery cells. Since then there have been issues with peak detecting chargers and those cells with the charger reporting a charged battery when that is not the case. The issue becomes more pronounced with higher charger rates or higher capacity battery cells. While there is some conflicting information out there, NiMH cells should not be charged at rates over 1/10C as a matter of course and probably not more than 1/2C on occasion. Here's a nice FAQ on NiMH cells:

http://www.hangtimes.com/rcbattery_faq.html

rclement

My Feedback: (1)

Thanks much, I appreciate the info. [8D]

mundo330

My Feedback: (3)

The NiMh battery is not always the issue but the size (volts) and brand. Many cheap NiMh batteries are on the market and have many issues. Some sold by a popular national distributor will not hold up to their specs or the capacity of the cell is not as advertised. I have checked new Rx packs for students that listed as 2300mah and found them with capacities as low as 1100. Also remember the reboot factor. Using Lipos directly connected to a receiver without either a bec or voltage regulator is asking for trouble with most servos. All but the high voltage rated servos have a maximum rating of 6 volts(nominal). While they can handle the voltage of a A123 the 7.4 volt Lipo is pushing the limit of reliability.
I have been flying for 30 years and have purchased my Sanyo NiCd/ Nimh batteries from the same trusted source for nearly as long. Sanyo does not even advertise to the hobby market because for years it was the only battery we used. Now with the flood of cheap Chinese cells on the market it seems the message has been lost. If you buy Sanyo cells that are matched and welded into packs with good quality connectors you can not go wrong. I purchase mine through E.H. Yost and will not go anywhere else! Also I have tried the eneloop cells in my 9303 and they work flawlessly plus I do not have to remove the battery to charge it.!

BuschBarber

My Feedback: (2)

I do use a 5v or 6v Voltage Regulator with my LiPo Rx packs as I am not running any HV servos that can stand 8v. My JR 791 Retract servos are only rated for 5v.

molokaiboy

Ihad an issue once that Itraced to a 4.8v power source. In my opinion my 4.8v rx battery dropped low enough under load that it caused my rx to go into a brown out/failsafe mode causing my heli to go in from a hover of 2'. Since then Ihave only used 6.0v or 2s lipo to power all my models. Ionly use 4.8v in my slopers or gliders where there isn't a very high demand on my battery.

Aloha,
Les

flycatch

My Feedback: (26)

I had a similar problem and it had nothing to do with batteries, receiver or transmitter. It's to late now but IMOP you experienced a faulty on/off switch in the switch harness. This is my decription of my crash. The plane was flying straight and level and than it roll to the left at full throttle and crashed. I had control of nothing. Prior to the flight I did the usual preflight and upon power up the airframe I had nothing. I recycled the on/off switch and the power came on. I did not heed this warning and flew anyway. Vibration got into the switch and turned itself off. Just a though I could be wrong but don't think so.