Mpizpilot

My Feedback: (45)

As I climb out from under my rock, a couple of things to mention. Battery was brand new and freshly charged. Again, I think it's insane to have to put a current meter on 4 futaba 3003's in a 40 size trainer to check the current draw. I run 6 volts in everything, whether it be nimh or regulated li ions. I put a 4.8v in the trainer bc it's just that, a low cost trainer.

Never in all my years of flying 35-40% 100cc and up aerobats did I once put a current tester on my 12+ digital servo, dual rx/batt systems with 72mhz.

The only thing I've gotten from this thread so far is I have to be even More tech savvy with a $80 trainer then I ever was in he past with a $5000 aerobat. Sorry, but that dog just don't Hunt for me.

Is this just a spectrum problem or jr as well? If it is jr also, I'm yanking it all of my planes and going back to futaba.

Scirocco14

IS it possible this was a buddy box/transmitter issue? I've seen a few of those at our field when our instructors try to hook up their newer computer radios to less expensive radios. Some work and some don't, even though it seems like it should.

Just a thought.

Mark

harlanb

My Feedback: (1)

Deleted my post as, I thought the OPwas using a Futaba system, and I was refering to the Futaba specifications.

BuschBarber

My Feedback: (2)

In 34 years of flying RC, I have never Had to use a Current Meter. We just switched to larger capacity battery packs and/or higher voltage packs. Anyone who flies electrics usually has a Wattmenter to determine the optimum Prop size or to verify that the motor, esc, and motor battery are rated for the amount of current being drawn.

I think you are over reacting. You have had an accident with your aircraft and you want to nail down the cause. You have been given some suggestions as to how to diagnose the problem. Switching radio manufacturers is one of those suggestions, however, it is still a good idea to get a handle on the current load that you are putting on the receiver you choose to use.

BuschBarber

My Feedback: (2)

Many manufacturer's receivers can be used with Unregulated 2cell LiPos (8.4v) although it is not always obvious from the Rx specs. Of course, you would need HV servos as well. The important thing is to have batteries with adequate capacity. Many use newer Digital servos that put much more of a load on the Rx.

eddieC

My Feedback: (2)

Really? If the flight lasts 48 minutes, as mine do, I'd call it good.  [8D] This is a pack I assembled from matched Venom car cells. You assume many of us don't know what we're doing. I know how to set up a plane, build and cycle packs, and I pre- and post-flight my equipment.  

Again, your two-year timeframe is, TBH, laughable. Cycling is great, although a 20% loss is pretty high. Anything over 10% loss to me gets questionable. I guess you're using/testing some very cheap off-brand batteries to begin with.

About half the guys at our field should be crashing using that standard. [X(] They know their packs are old, but cycle occasionally and keep flying. Some of our planes are 30+ years old. My one flying bud (who was a CL national champ many years ago) admits he flies a pack in one pattern plane that he can't recall ever replacing. 10+ years old, cycles OK.  It's buried and is hard to get out, he says.

My old-timer is a Zephyr (British, IIRC) with a brushed 600 geared 4:1 with 12/6 or 13/6 props. The 10-cell 3,000 ma nimh brick helps both CG and ballast on windy days. When this nimh pack dies, I'll go with LiFe chemistry. Should get 1:15 flights then.

dwaynenancy

My Feedback: (62)

No one has suggested Spec/Jr's correction to fix "said" problem. Spectrum has a part called SPM 1600 Specktrum Voltage Protector that plugs into an un-used port or in parallel with a function. It's just a capacitor to hold the voltage up in case of a "brown out". How do all you people plug your 2 battery systems into the rx? Dwayne

BuschBarber

My Feedback: (2)

I have used a Redundant battery connected with a Y to a servo port. I have also used the Isolator, from i4C, to utilize a small Rx battery and two larger Redundant servo batteries. Others use Power Expanders, such as from SmartFly.

Spektrum has PowerSafe receivers designed for Redundant Rx batteries.

grimbeaver

All depends on the application and gear. I've used 4.8V rx packs just fine with my Hitec 2.4 ghz gear. Hitec doesn't brownout until 3.5V, well below where your 4.8V pack should get to if you are responsible.

grimbeaver

Very interesting thought. If the buddy box cable was acting up / shorting out who knows what would happen. And he said that he flew it just fine himself, was the buddybox connected during that flight? I'm guessing not.

P47Tbolt

My Feedback: (20)

I just setup a Wild hare Edge 540 50cc using Power HD 1501mg servos,DX8 and an AR8000 receiver with telemetry.
Battery is a Hobbico Life 6.6v 2100 with 2 switches.One switch is a JR chargeswitch(JRPA004),the other is a switch I bought from
the Perry r/c swapmeet for $10.00 that looks like a JR chargeswitch but is not.with the telemetry I can see what voltage is at the receiver from the DX8.It records min and max voltage automatically on screen.With just the $10.00 switch on my voltage was dropping to 3.9v from 6.6 while operating all servos.With just the JR switch on the voltage would drop to 5.6v from 6.6 while operating servos.with both switches on it would drop to 5.9v from 6.6 while operating servos.
voltage drop is servo load and from resistance in cheap switch,you also have some resistance in all the connections between receiver and battery.keep connections to a minimum.I wonder what a 4.8v pack would drop to with a bad connection or cheap switch.probably enough to make the receiver reboot/brownout whatever you want to call it.
I am actually looking at replacing all my receiver switches in all my big planes with just a deans plug between battery and receiver.I would have to take off canopy every flight,but that would be better than loosing a plane.

warbird_1

My Feedback: (61)

you can poke fun if you want ,but 4.8 is not the way to go with 2.4 . maybe if you crash enough you'll understand why. they shouldn't even be sold with 2.4 systems period . i throw mine away.

warbird_1

My Feedback: (61)

wow , thanks for the example . good stuff to know. i run only JR HD switches

sebo

I definitly will upgrade my batteries.......I appreciate all that has been put forth in this thread.
my flying buddy flies electric and has so many devices for checking everything at the field that I am sure that his checking my batteries before I fly has kept me safely airborn for the last couple of years......and I do recycle.....Caught a low battery in my Citabria a couple of weeks ago.....
This is especially important in our hobby.....safety does come first.....Thanks guys.....keep puting out the info.......some of us are so old that we get into a rut and are too lazy to do a little research.....we let you do it for us.....thanks, again,,,,,,,,,,,SEBO

gsmarino2000

My Feedback: (2)

Sorry, but I don't buy that this is a simple brown out situation caused only by the choice of a 4.8V Rx battery. There are just too many people (myself included) who fly more complex, higher current draw planes successfully on 4.8V with JR/Spektrum. I have run current draw tests on my larger gas planes but never on my smaller glow planes ... but I will set it up before my next flight. I am also going to see if I can stall 2 or servos at once and cause a brown out.

I think all of my JR and Spektrum Rx's are the newer fast recovery versions, but if I can induce a brown that way I'll be curious to see how fast it recovers.

Greg

mike31

My Feedback: (67)

Yeah, me too!

silvermansteve

My Feedback: (2)

i trust my tactic, futaba and HOBBY KING 2.4 radios more than my spektrum dx3s.  who needs a finicky radio?  i've had a few brownouts using my bec equipped esc running  4s lipos.  also, i've heard too many stories like mine.  why defend spektrum?  by the way, as for my futaba, tactic and hk radios?  so far, so good.

helisrme

Folks,
I know the feeling. A couple of weeks ago I was flying my ultra micro Hobbyzone Champ half throttle into the wind 300+ feet trying to stay in the same spot/area for a few seconds while a PC-21 military trainer from Columbus, MS Air Force base cruised by at around 400 feet or less taking only 6 or 7 seconds to get by..... I only had my eyes off mine for 4 or 5 seconds and once I turned to look in the area it should have been.... it was no where within 360 degrees. I searched everywhere in the area and far out away down wind in wide open fields from the point of loss to NO results.....

Either the pilots of the PC-21 had thought my ultra micro was a threat and had a particle beam weapon and zapped my plane out of the air not even leaving dust particles. Or, that was a UFO disguised as a PC-21 and took my plane. Or, my Champ got sucked into a wormhole. Lost in the woods just isn't processing in my mind ; . )

gsmarino2000

My Feedback: (2)

Okay guys,

1/7th scale P-51, 8 servos. Control surfaces Hitec HS-525, throttle HS-522, not sure on the flaps. Robart mechanical retracts with JR 721. Battery Sanyo 1650mAh 4-cell 4.8V NIMH, receiver JR 921. Assembled the plane inverted on a stand. Battery was flown out 2 days ago and has not been reharged. Checked with Futaba BR-2000 at 1 A loading, reads 4.6V in "warning" zone on display (note that I would never fly in this condition). I exercised the servos for approx 10 mintes stalling various servos and operating everything at once on high rates trying to induce a brown out - nothing. Now bat reads 4.4 V @ 1A in the "Danger" zone on display. I clamped both ailerons and the elevator with quick clamps and foam sheets. With the three HS-525 servos stalled, I also simultaneously operated the gear and flaps - nothing. No brown outs, no evidence of problems. I removed the wing looking for any alarm codes on the receiver. Nothing. I believe that the HS-525 stall current is approx. 440mA at 4.8V, no load is 150mA. Total load on the battery with gear cycling, etc. was probably around 2A. End voltage of the battery checked with the BR-2000 was 4.2V @1A, 3.4V at 2A. That's as much as I care to abuse my servos.

Sorry guys, but I believe this test is more severe than the plane will ever see in real life. I started with a lower voltage than I would ever start a flight, ran the equivalent of at least 1 more flight with excessive load, and then simultaneously stalled 3 servos with no problems. You may think I'm foolish but I don't have any plans to change out my 4.8V packs on these 60-size planes.

Greg

MetallicaJunkie

ive had my share of probs with the ar6200...bad receiver, i know of atleast 3 other guys who have had probs with those receivers too

Luchnia

My Feedback: (21)

You guys that have trouble with your JR/Spektrum stuff are more than welcome to send them to me as I will take that trouble off your hands and that will end your problems with that garbage. I will take AR7000, 8000, R921s, the radios etc. You know you are bound to lose a plane with that junk.

I will take them all and would even consider paying shipping charges for those bad devices that are browning out on you. This is a good solution and will rid you of those pesky JR/Spektrum problems. Why fight it? Just do it. Move over to Futaba and be happy and I will deal with the faulty JR/Spektrum junk that is costing you all those headaches and crashing your planes.

The best way to rid yourselve of this serious problem is to get rid of the troubled items and you know you don't want to sell those defective componants to any fellow pilot KNOWING that he/she would have the same problems as you are having now would you? I will put it in writing that I will not sell the componants to any fellow pilot as long as they are validated defective by my research and testing. Why take the chance on losing any aircraft that cost thousands to such defective devices?

I am here to help you out of this dilemma the easy way and save you much hardship, grief, and lots of hard earned money. [8D]

AndyKunz

There are panel-mount Deans setups for this kind of purpose, mostly from the niche companies. You are correct about the high resistance being a problem - not just the switches, but also the wires.

Andy

BuschBarber

My Feedback: (2)

Are you talking about Arming Switches? I use them on all my electrics (except for the foamies).

http://www.rcaccessory.com/armingswitch.aspx

http://www.maxxprod.com/mpi/mpi-21.html

I use them to cut the power to my ESC until just before I am ready to takeoff. This way, I can attach the motor batteries, secure the canopy, and then wait to fly. They could be used for Rx batteries, as well.

wcmorrison

My Feedback: (2)

Yes, by all means go to a five cell receiver battery.  And get plenty of capacity in milliamp hours.  I prefer NiCd as they decline gracefully and tolerate big short term demands on them.  If you go NiMh get something on the order of 2500 Milliampere hours cells, do a good job on initial charging to properly break in the battery.  Remember NiMh do not fail gracefully, they have a distinct knee in the discharge curve and will drop like a rock when close to complete discharge - in other words now you have it and then now you don't. 

And finally, and this is an opiinion, get rid of Spectrum equipment.  I have had nothing but trouble with it.  Go to Hitec or Futaba.  JR/Spectrum was to early to market and had lots of problems.   One of which is being discussed here, the drop out issue.  Futaba and Hitec seem to be a lot more tolerant.  And Spectrum did not broadcast their problems with loss of lock, battery issues, it came out only after people started calling their tech department and they said do not use four cell (4.8 V) receiver batteries.  The word spread rapidly but still to this day they ship their  equipment with 4.8V batteries.  Tells you something about them, doesn't it.

dwaynenancy

My Feedback: (62)

Why not get a Mirical or Jim Odinno switch which removes any switch failure to "on" and go from there.