Lucky day for Rcpete
 

HI all, today was the first outing at Wingham to start the Jet season.
I brought my New Futura Audi to fly, it had already flown in Florida.
The day started normally, put the Futura together, checked all controls, cycled the gear and fueled up.
I then wheeled the Futura to the start up area, started the Behotec 220 ,( love this turbine )and checked the controlls again, no steering on aux 4 through the Power box Royal, ends up the Power box channel was completely dead, by the way, I am well versed with Power Box, I have one in every one of my Jets.
Moved the steering to the Rudder channel.
At this piont, just decided to do some taxiing and handling on the runway, as their was only 3 of us out this day.
Decided not to fly today and taxied back to the pits, the flaps at this time was set for take off, while walking back the left flap, suddenly dropped straight down and locked, the right flap just locked, ends up, now the flap channel on the Power box is also dead, lucky I decided not to fly.
Rcpetehttp://www.rcuniverse.com/forum/atta...mentid=1986376http://www.rcuniverse.com/forum/atta...mentid=1986377http://www.rcuniverse.com/forum/atta...mentid=1986378http://www.rcuniverse.com/forum/atta...mentid=1986379http://www.rcuniverse.com/forum/atta...mentid=1986380http://www.rcuniverse.com/forum/atta...mentid=1986381

Wow that's quite disconcerting. How do you think this could happen? I would think something of this nature would be extremely rare with the Power Box.

Hi Pete.

I think its alarming that you decided not to fly. Look at that beautiful runway you have there :)

Paul.

Yes, I think it is rare, but it makes me sick to my stomach that I came so close to loosing my new Audi.
Rcpete

Pete,

I'm glad you caught it before a catastrophe. I don't know if you're aware,but I recently lost a brand new Ultra Lightning on the maiden flight, and one of the primary suspects is a brand new powerbox cockpit SRS. Everything was brand new, top shelf in the jet,built by a pro. Futaba 18 MZ, 2 sbus Rx's, into the powerbox, fed by 2brand new Electrodynamics A123 batts. Locked on a knife edge pass, sailed for a few hundred yards, then a violent snap into the ground. ECU data shows "rc signal loss" as last off condition,and the last perameters showed normal full throttle,then data ends.

My failsafe was set to hold flight controls, kill the engine, and extend the landing gear. The gear were still retracted at point of impact, so I believe it was not a hold/failsafe/signal loss, but a power failure. One batt tested ok, post crash. The other was untestable. Powerbox was destroyed. All linkages were still intact, and servos tested with a driver,and worked perfectly. 8711's all around. My buds are thinking a bad cell in one pack drew down the overall voltage, but I give even money on the powerbox. Replace it before you fly your jet. Good luck,

Erik

I'm glad you had luck on your side, Pete.

Last weekend I went to fly my Eurosport with a new iGyro with GPS. GPS was seen by the iGyro but never locked satellites. Replacement came today and found satellites within 1 minute. Can't understand why this equipment is tested at the factory.

Nick

Erik,

I'm not 100% familiar with how the Powerbox works, but I'd assume that its the same as the Smartfly that I use. If so, then a total failure of one battery will not bring down the voltage to the servos/RX - they are isolated. If they weren't, then they would be pretty much useless, as 2 batteries means twice the probability of failure *unless* the system can operate on one battery despite any type of failure on the 2nd battery...

I'm curious, is the connection between the Futaba receivers an Sbus connection (i.e., only one servo wire)? How about between the Powerbox and the servos, is that Sbus too, or does the Powerbox do the serial Sbus-to-parallel PWM conversion?

Bob

I heaved close to disaster situation to so after 6months no flying ,,Chicago ,, I did one flight with small t-28 to refresh reflexes ,so after the flight I was going to fly my eurofighter ,when I changed model to euro I spot some funny squares right after the model mane ,the jet bind and the p-140 rx start and all was working good the funny symbols stay on my screen so I did turn the jet off and the radio to make one more bind and start when I turn the radio on nothing on the screen just two big black spots and lines - the radio just stop working ?,,good I did the startup one more time:rolleyes: ,the battery freshly charged and the radio most trusted for more than 6 years jr-9303 :confused: just got new one spectrum DX-18 QQ and now I have 7 jets to do new setups and maiden flights ,lucky me ,I never used the power box just the power safe rx with two life 2300 to 4000 mah ea .

I agree with you on that, there is a saying "keep it simple stupid" or kiss, this is a rule that applies to just about every engineering trade weather mechanical or electrical. I use the minimum needed to get a reliable connection between my battery-receiver-servos and as few unsoldered connections as possible.

Completely agree, 2 life batteries and a receiver is all you need! just cant wait for the dsmx powersafe 18 channel receiver if they ever make one

OK, some of the plus when using a Power Box System
-the best switch to turn on 2 batteries
-shows the voltage of both batteries
-has exterior lights to signal pilot of battery failure ( hopefully that is one battery)
-provides a constant 5.9 or 7 volts to your system
-has over 20 sockets for muliple servo installation
----- the big one is, if you have a stalled servo, it is taken out of the circuit and still have a chance to land your plane.
-2 receivers can be installed
-and the list goes on
Rcpete
PS, the latest PB's, now have sequencers and gyro

but do you need all of that? I have a 14 channel futaba 6014-orbit powerjack- powerbox Gemini-4000mah lipox2 the powerjack boosts the signal and the switch is a twin fail safe with twin inputs to the receiver.
the switch regulates the power, you can still have two receivers if you want and why would you want a gyro it just something else to go wrong which goes back to the saying "keep it simple stupid"
not that I am implying you are stupid but its just part of the saying.
regards
jay

Hi Bob,

I've been playing with a Powerbox Royal SRS for a new install. Previously I've been a happy user of the SmartFly products which have always served me well. Since I really like the iGyro, if you look at the pricing of the PowerBox products, the Royal SRS, even though quite pricey, is a good deal since it has the iGyro integrated, and has some very nice features regarding power distribution. I have a hybrid setup in my Skymaster Viperjet with the Smartfly unit and an iGyro and it works just fine. I was going to replicate that when I saw the Royal SRS unit.

FWIW, reading this thread with folks worrying about the PB stuff as potential reliability is disconcerting, but lately this forum has turned so sour that we seem to be able to turn a sunny spring day into a problem :-(

As far as I can see, since you can reassign functions in the PB (the outputs designated by letters on the PBox) to Sbus channels freely (that is you can have any Powerbox output letter run to any one of the Sbus channels that it puts back out) .. they must do exactly what you say .. they go Sbus to parallel channels, do all of their servo scaling transforms, then create their own new serial data stream and send that out the two "Powerbus" connectors. These are just Sbus signals coming out of two MPX connectors on the PBox, each of the two Powerbuses is supplied with its own regulator system. They have some interesting accessories to distribute the Powerbus that handle current overloads in an intelligent way.

And yes, the only connection to the RX is the Sbus signal wire .. the RX gets power from that and sends signal to the PBox.

So far I am liking the device, though it does offer a philosophical conundrum .. should you leave the TX ATVs all at 100% and set all endpoints and reversing in the PBox or vice versa. You now have two places in the system that can do the same things to the output channels. In earlier lower channel count systems, you'd use one TX channel for a function, and that function might drive 2-4 servos (e.g. ailerons in a big 3D plane) .. and clearly that's the sweet spot for a PB system handling all the servo spans and endpoints in the plane. But with systems like the 18MZ where you can afford to do one channel per servo, it's less clear this is an advantage since you can do it "per servo" in two places.

Lastly, and perhaps this is something you have run across .. suppose you use two R7008 RX's with the PBox as it is intended to do. Further suppose you are doing telemetry. You presumably connect the Sbus2 telemetry to only one of these RXs. Since the RX with telemetry enabled also transmits periodically, how would the two RXs synch so that the non-telemetry RX "knows" when the telemetry RX is transmitting down to the TX? Seems if they were not synched, the transmission from the tele RX might swamp the input stage of the non-tele RX and make a big mess ... I've been wanting to ask one of the Futaba guys to run this down -- any ideas on this?

Dave

Dave, I think (and I write "think" !) that the reply back from the receiver to the transmitter is synchronized with the signal from the transmitter so that the (master RX) is sending the telemetry data back when the transmitter is "listening". The two receivers received the data from the transmitter at the same time so I don't think that the other (slave) receiver would be blocked by the master receiver sending telemetry data back

But it would be nice to hear how this exactly works (or if someone could do some measurements "on air")

How do you feel about using them in the rest of your jets? I've seen more failure threads than "I love powerbox" threads.

I know the features and have seen them working and they look great and failure is rare really but...

There are other switches that show voltage so will show a problem with a battery, there are rx's that can isolate bad batteries (I believe) and I have seen stalled servos on jets without any fancy equipment make it down fine.

if a servo is stalled you can recognize the issue right away and if you have enough capacity in your packs you can make it down just fine

This is scary. Has the manufacturer addressed this issue with public statements, or replaced any defective powerboxes?

Been using Powerbox products for over six (6) years now and I have never experienced a problem with them. I have installed nine (9) Royal's (lately the SRS version) and they have always worked for me. The latest version is extremely easy to program and it's fully loaded with options like iGyro.

Almost everybody at our club uses Powerbox without a problem and the only time I have seen one fail has been because of user error while trying to adjust servos (JR 8711).

Not saying that a failure can't happen, but this is a great product and they will take care of you in case of problems. Just send a note to Emerich.... he is a supper nice guy and will be very honest in his responses.

Same here,
been using different types from them, never any problems

A week ago I was talking to Emerich that visited us for our Andes Jets 2014 event here in Chile, and he mentioned that he has seen some problems with the JR8711 servo. Basically, this servo can burn very fast if jammed and that could affect the Powerbox. Actually, I have seen that happened at our club while somebody was setting up his plane.

In my planes, I have a mix of JR8711 and Futaba 9157 but I have been lucky that none of them have failed. As I said earlier, really like the product and I wouldn't assembly a plane without one of them.

Has anyone tried the Secure Flight by Down and Locked powerbox. I purchased one at Toledo and was going to put it in my new SM Viper

Was there a reason you decided to move the steering to another channel and not determine why it failed? I would have grounded my aircraft on the spot until it was resolved, no luck needed.

Dave,

From your description of the PB with Sbus, and reading up on them, its clear that there is *significant* software inside them. Putting something like that in the critical flight control path always gives me pause, especially given that in this case, its a single point of failure.

I like the Smartfly stuff because its a simple analog battery selector switch, analog regulator, and analog signal boosters for the RX to servo signal link.

We have software on our autopilots that have hundreds of flights and hundreds, if not thousands of hours of hardware-in-the-loop simulation time on them, and we still occasionally have a "what was that" kind of experience - quite a few of which would have caused lost of the aircraft if we didn't have a safety switch to let the safety pilot take back control.

Our autopilots have a safety switch function that allows the control to be taken back from the autopilot to the direct signals from the RX (Futaba FASST in our case). This switch is controlled by a separate micro that *only* looks at the pulses from the manual/auto PWM channel and makes the decision which is in control. Also, the switch is architected to be "fail passive" such that if the autopilot looses power, the RX and servos are still powered and the PWM signal can pass through...

Bob

Peter..... did I just read correct, you said: started the Behotec 220 - ( love this turbine ) . That is refreshing to hear you say that.

It is rare to have PowerBox failures but Blair also had a PowerBox failure on his Tomahawk Hawk a couple of years ago, it was new, they replaced it for him
Call PowerBox and get it looked it.

Good catch and good call.

I agree to a certain extent. There is enough going on in a jet that's why I am going back to simpler ways now and making as little add-ons as possible, as little interconnections between one ebox to another to another, but Power regulation and backup is crucial (never Y 2 batteries together) and on larger jets, Power regulation and Rx Redundancy.

Worked well for years. Replace batteries frequently and if you suspect any component, replace it, don't bother repairing it or taking the cheap way around.