Robert:
I have a 33% SDmodels YAk that was outfitted with a DX-7 Spectrum radio. The plane had a good range check, and flew great for 5 minutes. I`ve been using SmartFly in all my giant scale airplanes without issue (30,33 and 35% YAKs and one 75cc extra) all of them with PCM radios. The plane in question was latter outfitted withnthe spectrum radio and after 5 minutes I was bringing it for a landing. The engine was just a tad above idle and turning to final. Then dissaster!! the plane did not respond to anything. Went in with the right wing and engine.
I`m trying to discard as many factors as I can ti find the problem, so I`ll give you my set up to see if I installed everything correctly.

The plane has 4 hitec 5985s on ailerons, 2 on elevators, 2 futaba 9153 on rudder ans 2 tower ts70 on engine controls. The receiver is a 7 chanel that comes with the DX-7 and to a SmartFly power xpander Sport. The power expander has two jumpers that connect to the SM Super Regulator and a single 5200mAh Li-Ion Denko battery is connected to the regulator. Everything is switched off by means of a pin-and-flag switch to the reg.
The power expander has 8 pigtails, so we connected the 7 that we needed and I tucked the one left over away under the PE.

I know how the SmartFly equipment works and have been using it for the last 2 and a half years with no issues what so ever. This plane had 47 flights with this set up, but with a PCM receiver. The crash was on the first flight with the 2.4GHz.
My question:
Is the pwer expander sport compatible with the spectrum receivers?
Could the "brown out" condition occurr with this set up?

As I said before, I`m just trying to find the answer to the possible cause of the crash, I know the regulator and power expander are not at fault because I know what they can do and they do it well and after the crash they were both checked and they are in goo working order.

Thanks in advance Robert,

John

Did you follow Smart Fly's recommendation not to plug the Smart Fly power into the receivers power jack? That will cause the receiver to lose bind at random times.

Yes, I did. All the Power Expanders pig tails, except one with only a white wire, were connected to the 7 chanels of the receiver. The batery port of the Rx was empty.
John

Yes you could have a brown out, you could have lost the bind, you could have had shadowing of the RX's, you could have had interference.

Post crash inspections are always hard.

I would send in all your Smart-Fly gear to them just to rule out it didn't fail (highly unlikely but could have).

I would also send in your Spektrum gear.


How did you accomplish the range check?
Notice anything different there?
Were the batts salvagable? Have you cycled them to see what capacity they still hold?
Where were the antenna's placed in the plane?
How is your TX battery?
Did you accidently hit the bind button on the back of the radio while flying (using a transmitter tray?). That will reduce power

Hi sweetpea, the range test was good to go, we did it as the instructions on the manual, there was no alarmas in the range test.
The batteries had almost 4500mAh in them, they are ok, no punctures or anything. They were recharged and reaches the 8.4volts with a little less than 5100mAh.
The antenas on the main receiver were placed on the power expander, all wires were held down everywhere so they would not come near the antenas. The other receiver was placed to one side of the fuse at 90° to the first one, there was nothing close to this receiver.
The Tx battery is good, it had a full charge and voltage before the flight.
No transmiter tray. The plane was flying fine for 8 minutes, and in final aproach I had no control.
And for a fuse that was completely destroyed, all servo wires, battery wires and PE/reg wires, were all connected in their places. we just picked up all the wires and the equipment came right off the crash site. We turned everything on again and everything worked ok after the crash.

Any other thoughts?
John

How was failsafe set?

If it was set, do you feel the plane went into failsafe?

If it did then you can cross brownout off your list. If it did not feel like that, then you possibly had a brownout. Do you know if your RX is the updated version that blinks on brownouts?

The failsafe was set but it didn`t feel like it was in failsafe, the plane just kept banking to the right and down until it was almost vertical.
The receiver is brand new, it`s the second receiver i got for the radio, the original is in another airplane. This one was binded to the radio and installed on the plane. Everything seemed to work ok.
This new receiver does blink when it is being binded, I have not seen it when it is in brownout condition.

John

The ar7000 receiver only has smartsafe, which means it will hold the last known stick positions except for throttle.

Hi John,
Sorry about the loss. We have been flying using Skektrum, JR and Futaba 2.4GHz for almost 2 years now and have not experienced any problems here. We flew a DX-7 for almost a year testing all our new stuff, no issues. I really do not have any idea what could have happened. You can send the stuff in if you want me to check it.

I fly Smart-fly on all my planes as well with no problems on 2.4, sending in your gear is just to check that gear off as a possible problem

The brownout check is easy.

1. Turn on the radio
2. Turn on the RX (I prefer a switch inline on the battery)
3. Turn the power off to the RX but leave the TX on
4. Turn the RX back on. It should reconnect in approx 1sec or less and the lights on all RX's (including satellite) will blink until you power off the RX and TX together. If it takes longer than 1sec to reconnect and/or your lights do not blink then you have the old system. The upgrade is free by Horizon.

The brownout upgrade doesn't stop brownouts. What it does do......when you have a voltage spike (say from a binding servo) the RX will shut off when voltage is below its threshold. It will then reboot. It reconnects back to the original 2 freqs it was on so the reconnect is much faster.

This could have been your problem. 2.4 RX's are much more prone to voltage issues than PCM RX's were because they are more like a mini computer than just a solid state device. Since this was your first flight on 2.4 it leans toward that. Also I believe you were running only 1 battery (in this size plane that is common). Your battery might show voltage being fine but this is a case of something like a servo stealing voltage from the RX.

Of course with the SF powerexander you should not have seen that.

Again, its only a guess. There is truly no way to know exactly what happened. All you can do is start from the beginning and rule out things that could have failed. You may have just got interference and yes that can happen even on 2.4

thanks for the brownout tech check list sweetpea! i wasn't sure how to check my system for the New or Old components.

all I use is Spectrum and SmartFly products in all of my planes with no issues.I even have the same set-up in my sons plane and no issues ,you had to of had a "brownout".

Thanks for all the replys guys... I will do the procedure sweetpea posted, as you said I might have one of the old receivers and the Tx is about 2 years old.
i will do as you said and the reply my findings, if this doesn`t tell me what went wrong I will send the equipment for a check up.
Thanks again to all,
John

Originally Posted by juanes1969

The receiver is a 7 chanel that comes with the DX-7 and to a SmartFly power xpander Sport. The power expander has two jumpers that connect to the SM Super Regulator and a single 5200mAh Li-Ion Denko battery is connected to the regulator. Everything is switched off by means of a pin-and-flag switch to the reg.

Everything you have described points to a power fade of some type. What is a SM Super Regulator? I'm not familiar with this product.

My suspicion is that after several minutes of flying the voltage regulator got hot and ceased to function properly. This would account for the fact that everything was working after the crash, a regulator can overheat and stop, then when it cools off a little it comes back to life.

One reason I don't like using regulators.

TF

Hi Tom, the Smart-Fly (SM) Super Regulator.
I agree that regulators can overheat and cease to work properly and this particular plane had another type of regulator before (MPI first and duralite after that) then I switched to the super reg. With the other two using normal JR connectors on batteries and receiver, the plane flew fine without any apparent voltage drops. These smaller regulators were rated for 7.5 Amps Max. But the servo type connectors can only deliver about 3.5 Amps. I have another super regulator working on my 35%Yak with stronger servos and has about 20 flights in it without problems.
The Super Reg. can deliver 7.5 Amps cont. and 15 Amps peak and has deans connectors in and out (two each way), the plane has never been flown for 3D, only IMAC at 1/2 to 3/4 throttle with IMAC throws.
I guess what Iīm trying to say is that I donīt think the super regulator is at fault (but I could be wrong) because it has more than the recomended power for this plane and my type of flying.
As I said, I could be wrong and the reg. could be faulty, but I couldnīt reproduce the fault in the regulator.
How ever, I did try the receiver again. I connected all the gear I had the same way it was in the plane, but this time without the plane itself (it was completely destroyed in the crash) all servos are ok, and the power expander and regulator seem ok too.
The receiver binded as soon as I turned the equipment on, so I started to move the sticks on the transmiter.... nothing happened. Ohh i forgot to say, I pluged a voltmeter to one of the empty slots on the power expander. thevoltage was kept at 6.1 volts which is the set up I did on the regulator.
So I took everything out of my shop and tested again using the same battery the plane was using.
I did a range check to 35 feet 4 times because on the first one, the receiver stoped working. For some reason the receiver started to bind again when I did the tests at 35 feet. it did so on the first, second and third range test, but not on the fourth. It took about 4 seconds for it to re-bind.
I will be sending the equipment to be checked, I really donīt understand what the problem could be so Iīll let the pros find it.
One thing that is really weird is that the problem only occurs with the new receiver, the one I bought a few days ago. The original receiver the radio came with does not have this problem. the range test with that old receiver are perfect.
Iīll wait to see what they say after checking it and will let you guys now what they find.
Thanks for the help,
John