Mitsu1

My Feedback: (13)

Amazing to me how no one has questioned the Power Expander. I now see the owner of Smart Fly has dropped a line in to keep the conversation elsewhere. I've never heard of any electronics built on a PCB that can't develop circuitry problems.

Bob Pastorello

My Feedback: (198)

That's not accurate; you should read the whole thread. Early on, the PE is discussed, and one person who had a failure was asking about similarities of failure mode.

This has been a good thread; I think there is some learning going on, even if Jake isn't any closer to conclusive failure mode evidence.

quist

My Feedback: (198)

It is a good thing you were here to catch him in his coverup.

SinCityJets

If it is the PE that failed, it would be the first I ever heard of. I have sold a LOT of units and use them exclusively in my GS and turbine aircraft. The reason I use it, it has been bulletproof.

As far as the numbers you are posting on the A123's, they seem normal to me. even IF the battery dropped to 4.8v, that's not low enough for a re-boot. It may have been posted, but are you running 2 A123's to the PE (sill question, I'm sure you are).

And finally, don't put too much weight in the "fuel gauge" on the 4S. It is OK at estimating the amount of energy in the pack, but after building, selling, and test charginf over 750 packs, I am here to tell you I would not use it for a "Fly / Don't Fly" scenario.

Feel free to PM, email, or call with any A123 questions, and I'm sure Bob would offer the same for SF questions.

Josey Wales

My Feedback: (61)

[/quote]

You can't be more wrong. Robert R. is one of the good ones.

Panzlflyer

My Feedback: (15)

He was running One pack with dual leads and if it was discharged to the point that it got to 4.8 (under load)it aint got nothin left and it goes from 6v to less than 4 with a slight load faster than you can reach out and touch the sticks.

MikeEast

My Feedback: (3)

Read a little closer, I did. I have never seen a Power Expander fail, I have 2 and have about 5 friends that use them, but I have seen 1 instance of a Super Reg failing and causing a similar problem.

I think Jake has eliminated that possibility though.

I want to learn more about charging and discharging A123's in simple laymens terms. I am about to try my first set in a new review plane and I want to be sure that I handle them correctly. [8D]

Mitsu1

My Feedback: (13)

Ok, maybe I shouldn't have made it sound like that was his intent. My apologies. With that said ... I think it sounds like the problem lies in the construction of the homemade battery pack (I do believe he was runnng just one), although I still feel if the ailerons and throttle were working, it should have had enough to at least affect the pitch attitude with the throttle cut back to idle. My second thought is in the Power Expander, which was serving what real purpose? One of the advantages of A123's is not needing a regulator. Why not just plug everything into the receiver? Not meaning to look backward, but anyways ... it seems the PE was not sending signal to the elevator servos, and if it wasn't battery .. what else?

Richard D Bahmann aka/Wrongway

My Feedback: (42)

This thread can't be a bashing thread.....nobody mentiond DA, JR, Hitec, or (forgive me if I left someone out)

I'll try to be positive but absolutely love the gang who come right on in and have a seat... and even start their post with "I haven't read the whole thread because I didn't have the time to....but I think,,,"[:-]

Jake I really wish you could have recharged from the crash to determine just how many mAh would go back in it. I did a test a while ago (before my TP-1010-A123 capable) and found that when I took off at 6.44 v (flight #14)I was able to acomplish the a 10 minute flight on a 16 lb yak with similar servos that you have..... The next flight (#15) started at 6.40v and after the 10 minutes flight was down to under 6v. I quit and took it home and then ran the 9C on servo test for exactly 8 more minutes (no wing servos plugged in for pure laziness) before the avionics cut out for low voltage. This was not with any aerobatic flight loads on it, just bench flying. Of the elevators, rudder and throttle hooked in the rudder ran the longest before it died. (shortest lead to receiver) The elevators went first.

If you had charged the battery and put back in say 2200 or so mAh I would say that the battery was the problem all along. My money is still on the battery as your failure point. (by chance can you recall the no load voltage after the crash?

If it was my stuff I would send it all off for service, buy an A123 capable charger that tells you how much which goes back in after charging and troop on. I flew my 35% Pacific Planes 35% for 3 flights on a single A123 2300 with the Badger and Smart Fly PE yesterday with full confidence (over 40 flights on the setup)...The EF Yak has close to 150 flights on the single A123 2300 which has never even been balanced....thats the one I get 15 flights of 10 minutes from full charge.....I don't do that regularly but 8 flights usually yields less than a half a battery which is the most I can do in a day. The 74 inch EF Yak runs a single A123 for flight and ignition.....all home made from the Dewalt packs. One more thing, who did your soldering and with what confidence was it? I have a buddy do mine who is an experienced electrictian and knows how to solder. He says that there is a lot to be said about a proper solder. We driled a hole in the tab and wrapped the power leads around the tabs before tinting and soldering. No way they wil just pop off, no cold solders to break when you least expect it.

Git-Er-Done!

WrongWay

Panzlflyer

My Feedback: (15)

Mike,
They are real easy and I wont go back but there is a learning curve...not steep.
As with all packs make sure you are really putting the juice back in and on A123s voltage is not a real good indicator, prefered is to know how much your particular setup uses and go on that, they recharge fast and easy, no peaking etc.
Bob has some good stuff on his pages as does Sin City and others.

BTW I dont agree it was his pack construction as he says he had quite a few flights on another plane using that pack.

I had an extra that I really liked and in an inverted low pass down the runway put it in hard, I blamed myself for dumb thumbs.
About 2 weeks later I still had the rear section on my table and the servos in the elevator...a buddy got to looking at the servos because he wanted them and noticed that both signal wires were cut, only way you could see it was untwisting the twisted wires.
Looks like the last time I was in the fuse I pulled the extension tight and my pull pull cut into them as I was inverted and the wires hung down causing loss of elevator.
The weekend before I had flown it and it had given a little judder from the elevators when inverted but thereafter was fine and as I couldnt see anything wrong, ignored it!!!
Little stuff....

Mitsu1

My Feedback: (13)

Wrongway, in the above quote, what was the reason for only gettting 2 flights out of the pack? Were you using a charger that just beeped and you assumed it was full without knowing how many mah you actually put into it?

Jake Ruddy

My Feedback: (40)

I completely agree that this has been a good thread... IF everyone took the time to read the whole thing I think everyone could learn something in it, whether it be related to troubleshooting, A123s, or whatever.. there is some definately good info in here.

Now to address some comments / concerns.

Yes I ran a single A123 pack made from a Dewalt 36v pack.. The pack had 2 pre made 20 guage heavy duty connectors soldered to it. I sanded the tabs and soldered I used a high quality 75w soldering iron to make sure the solder joints were good. I have made many of my own packs (non A123) and haven't had a problem to this point.

Well I my first thought was to look at the PE or the battery I have hit a brick wall there. I did all of the same tests with a second A123 pack and had very similar results in all areas. I can not with stress, temp, load, or fast movement make the pack drop to a voltage of concern.

Wrongway: The pack was fully charged before this all happened... I did not charge it until I did a lot of testing and even after all of that it only took 600 Mah back in. I have not drained the packs completely, but do plan to on any new packs from this time forward.

As far as questioning the PE and my choice for using one, I have very good reasons.
#1 They are generally bulletproof
#2 The Plus has an ignition kill in it, which I would have normally used anyhow.
#3 I started using 2.4, I wanted the best power to my system as possible and didn't have to worry about it.


If you read my last post you will see that I have ruled out the PE and the battery now. What I am corcerned with now is the lack of torque in the servos around center and wondering why I can push my wing down and put the surface back to neutral with not that much force. This can be done with teh PE and with either battery pack with or without the PE. There is a servo issue there.

In truth at this point I am starting to wonder if I got a bad batch of servos. The gear trains are not as smooth as they should be. I have 10 here that were all bought at the same time. I plan on rigging up something to test the power of each servo and compare them. My guess is that I am going to have 3 servos (from the plane that went down) that are below what the others are doing.

For those of you who would like to jump in and not read prior to this post please pay attention here. Everything has been questioned and tested using my methods and methods suggested here.. the whole purpose to this thread is to help solve an unknown crash issue, and to help me track the progress of breaking down failure points. It has grown beyond that know and has developed some value to help people troubleshoot things... its worth a read.. no bashing here

Thanks again for everyone's input and help!

Zeeb

My Feedback: (41)

Jake,

While I've not offered much in the way of input, when you've got Bob P, Bob R, Chad (Sin City) and others adding to your thread, any additional input from me would be "shot in the dark" kind of stuff.

I do appreciate your sharing this troubleshooting oportunity and I've learned a few things along the way. The great part is that this thread could be applied to any power/radio system.

Sorry for your loss, but thanks for going along with all the suggestions for testing purposes and posting your results with a lot of detail.

Jake Ruddy

My Feedback: (40)

Appreciate that Zeeb!

There's a good saying that comes to mind.. 2 heads (or more) are better than one and this thread has shown that.

This crash hurt, not only was a review plane (luckily I have everything I need to finish the review) but this was to be my IMAC plane for the season. I was lucky enough to fly the prototype and knew how well this plane flew. When Chris asked me to do a review I was happy about it because I was going to buy one either way for the season this year.

This crash hurt.. the season is close and I need to start over. That aside.. EVERY crash hurts us.. no one wants to see it. So in the end even if I can point the finger at something I did wrong, all those reading it can learn from that.

So not only has it been good so far for me to try and troubleshoot the problem... there is a wealth of info being shared in a positive way that makes it a good thread.

Mitsu1

My Feedback: (13)

Jake, When I PM'd about pics I didn't know you had lost the plane. Very sorry to hear of this loss. With that said, I certainly have learned and will benefit as I have the same plane, same color to be started as soon as I finish my Yak. I had thought of going with one 2300 mah A123, but now I will sacrifice the weight savings and go with dual packs. I have the AR9100 Power Safe RX so I'll take advantage of the dual batt leads. I've learned from this thread more about how I should interpret the info from my CellPro 4S. No doubt others will benefit as well. Hope you have the replacement up and going soon.

nitro wing

My Feedback: (1)

Jake
I know this Extra went in from a deadstick just some time ago.
I really wish I could help with diagnosing this one.
When it went in a few weeks ago did any of the servos jam and perhaps draw huge loads before you got to it and switched it off?
It maybe an important clue,was there any real damage or kinked wires on the last mishap before it totalled?
Have you tried any of the tests while out of range with a collapsed antenna? I guess maybe 2.4 does not work like that ?
Just a thought..and probably has no value...
You were one of the first to bring a build thread and some vids,its not right for you to loose this one after taking the time and sharing
this build and fly with us []

Richard D Bahmann aka/Wrongway

My Feedback: (42)

Mitsu1, see post #16

http://www.rcuniverse.com/forum/m_54...tm.htm#5423975

I was actually on my 14th and 15th flight in the above quote.

nonstoprc

My Feedback: (90)

Jake,

If it is the elevator servo(s) to blame, the problem should be easily reproducable. Jusgt hung some reasonable amount of weight on the servo arm and see if the servo can hold.

I myself solder most of my extended servo wires and A123 packs, never had an issue.


As several posts suggested, an A123 pack may not reach its full capacity until charged several times. So we may never know the true state of the pack at the time of crash. But if you still have a couple of cells from that DeWalt pack uncharged, it may be worthwhile to build another one and put it in the same initial charge sequence. Then test this new pack to fully rule out the A123 pack.

In your #1 post, you mentioned the elevator is not responsive when pushed. How high is the airplane and what is the airspeed at that moment?

Jake Ruddy

My Feedback: (40)

Nitro.. I went waterfall to deadstick from running out of gas It didn't hit hard enough to do that type of damage.. I was just going too fast to not over shoot the runway and did an "S" to eat of some speed and ate up just a tad too much and it stalled about 2' off the the ground because I stretched it a tad too far. Just really bent the gear and dented the cowl.


nonstop - I rolled inverted at about half throttle and as I pushed over the top I went to full throttle.. from the top I went to idle to a 45 downline. Thats when I noticed I had no elevator.. I thene played with throttle and rates on the way down. It went in pretty fast but below half throttle.

It was definatley not a battery issue... I played with everything on the bench after the crash and then for nearly an hr here the next day without charging the pack and the voltage read fine. I have tried another pack that was made at teh same time and has the same number of flights on it and all voltage readings etc are almost identical.

Aerobat

My Feedback: (6)

Hey Jake, I'd plug each of those servos one at a time into a different receiver with a known good Nicad battery straight into it. Then move it under load for a good while.

I find that the latest Hitec digitals have noisy geartrains. I actually sent a couple in because I thought the gears were trashed, but Hitec sent them back with a note saying they were fine and that they added some more grease. So far no failures (although you know I don't fly quite like you!).

rctom

Jake:

I read this entire thread, and would like to see answers to some questions that have not been asked yet;

1. How were the elevator servos being driven? Were you using two channels on the transmitter? Some people use just one channel and reverse the second servo. With the power box either method is possible.

2. Where was the throttle servo plugged in? Was it plugged into ythe PE or did it maybe go directly into the receiver?

3. I don't recall what you said, during this episode did you use any other control besides elevator and throttle? And if so how did it respond? I know it's hard to recall every action, I went through something like this once and it was a week later before I was able to remember clearly everything that happened.

4. Have you ever run load tests after the PE? I suggest making a multi-way cable. I have one with 4 servo connectors at one end going into a common Deans plug at the other end where I can place a load.

It sounds as if your battery pack is under-performing but not enough to cause a failure. I would want to see what the voltage is coming out of the power expander when it is under a 6-8 amp load, especially after 15 or 20 seconds. If possible I'd want to measure it in 2 places, right at the battery and then right at the load, to see what is performing how.

The other thing that puzzles me is this. You were trying to return the elevators to neutral when it failed to respond, yet the throttle was working. Returning to neutral requires almost no power, since the forces on the surface are trying to push it back anyway.

So if you think back, is it possible that the elevators in fact did return to neutral but then were unable to conteract the dive that was already in progress? This actually would make more sense and would indicate a lack of power somewhere in the circuit.

Tom Fawcett
Wild Hare R/C

PS: Call me about an IMAC plane.

Jake Ruddy

My Feedback: (40)

Hey Tom.. thanks for the response and phone conversation.

I am going to break down the answers so everyone can see..

2 seperate channels were used

Everything was running directly through the PE

I reall only worked throttle and elevators but my friend said I did use ailerons a couple times but I just slightly rocked it back and forth a couple times while I was trying to work the elevators.

I have monitored the voltage inline after the PE several times doing everything from stalling servos at full deflection with extended travel and manual force against the surface to moving teh sticks as fast as I can. I leaned on the surfaces with weight very aggressively and still could only get a low of 5.98 or so... not enough for a power failure of any sort.


The elevators went to nuetral as I came over the top and I stopped using them on the 45 down.. they were neutral and remained at neutral after that point.. my friend said it didn't break it's track at all out of speed changes and a rolling back and forth a bit when I hit the ailerons by mistake since I was on the sticks pretty aggressively hoping to pull up the nose

Appreciate the phone conversation once again.


As of now I am seriously looking at the servos and their lack of power.. I will be pulling out some other ones and comparing.

3D_Junkie

If you could have only thought to roll kife edge and use the rudder to pull out. Of course only the best think that quickly[:'(]

crazyjoseph

My Feedback: (3)

I would recommend the smart fly pro with the A123S . It takes the voltage reg. out of the equation. Losing a plane is a drag . But knowing why is a nightmare.

outssider

My Feedback: (23)

not knowing !!