Spektrum DX7 + AR7000 -> Total loss of signal
 

Guys,

I was flying my 1/4 Cap 232 and i experienced a momentary 'glitch' at the beginning of a loop causing the plane to veer sharply to the right. This was followed by another minor glitch after which i landed the plane immediately.

Did the usual checks, Range, Rx battery voltage etc etc. Then took off again. Probably a mistake! This time, at the beginning of a loop, all communication between a tx and rx was lost and the plane rocketed at full throttle smashing on the concrete. The result was not pretty. I even totalled my engine and carried 2 bags of balsa and ply home.

Upon retrieval, I connected the battery to the rx and the servos were all working. Tx voltage 10.4 v.

Set up:

H9 1/4 Cap 232, 26 cc MVVS Gas, 6.6v A123 rx pack, no regulatror, 4 x HS- 645 MG servos, 1 x HS 625 MG servos. The airplane was about 30 flights old.

I did a few heli flights later that day and the radio behaved well though i didnt take the heli too far away.

I have a few more AR 7000's and 6200's that I use and am very very very wary of going back up with something big.

What could have been the issue. Maybe I should shift to DSM X or probably Futaba??



Edit: Uploaded Pic

RE: Spektrum DX7 + AR7000 -> Total loss of signal
 

Is you AR7000 capable of using the Flight Logger? Does it have the Firmware that displays a flashing light if the Rx experiences a Brownout?

The Flight Logger is a nice tool to help identify if you have had any Antenna Fades, Frame Losses, or Holds.

I understand your apprehension. All I can say is that I have had no problems what so ever with my AR7000 or any of my other Spektrum Rx's.

RE: Spektrum DX7 + AR7000 -> Total loss of signal
 

yeah even i didnt have any issues with the AR 7000 till now. It only takes 1 I guess! Mine is the older version with quick connect...

RE: Spektrum DX7 + AR7000 -> Total loss of signal
 

You might want to send it back to Horizon and have them take a look. You could also try reorienting the Main Rx and the Satellite. If you have a Wattmeter, you might want to measure the total current drawn by your receiver and servos. Are you sure that your servos can handle 6.6v? I use these servos at 6v, or with LiPo Rx packs and a 6v regulator.

RE: Spektrum DX7 + AR7000 -> Total loss of signal
 

all servos were similar. I experienced a lockout, but howz that possible with servos like the 645MG which are less current hungry and a fully charged 6.6v A123 pack capable of 50C bursts...

RE: Spektrum DX7 + AR7000 -> Total loss of signal
 

Since both problems started at the beginning of a loop, could there have been a loose connection which was affected by the increased gee?

The first time it made the connection again but the second time pulled out of contact and stayed that way?

RE: Spektrum DX7 + AR7000 -> Total loss of signal
 

With 72mhz, when an apparent glitch occurred, the question asked was:

Is it the wind?
Is it my radio?
Was it interference?
Was it Pilot Error?
Was it a mechanical or electrical problem

While you can experience interference with a 2.4Ghz radio, it is very unlikely.

Start looking at all of your servo connections, switch harness, battery connections. It may not be any of those, but it is worth investigating.

RE: Spektrum DX7 + AR7000 -> Total loss of signal
 

After the first flight when you landed did you notice if the receiver lights were blinking? If so it indicates a power loss or brownout.

Starting a loop will be putting a lot of strain on your servos and drawing a lot of power. That is the most likely time for a brownout.

What you need to do is draw a load of 6 or 7 amps THROUGH THE RECEIVER and see what happens. Make a rig with two extensions that each end with an 1171 light bulb from a car lighting both filaments. Each of those will pull about 3 amps. Plug both extensions into open slots on the receiver and turn on the power. Check operation in this mode.

I'm thinking a point of resistance in the power wiring, maybe a poor switch or bad connector.

TF

RE: Spektrum DX7 + AR7000 -> Total loss of signal
 

Lastly, was this particular receiver ever subjected to a crash in it's prior life (if, of course, it was ever used on a different aircraft)? If so, was it looked at by Horizon for any potential problems?

CGr.

RE: Spektrum DX7 + AR7000 -> Total loss of signal
 

Did you have the receiver mounted in a way to protect it from vibration? I've seen one AR7000 quit working on a gas powered plane because the receiver was only mounted with Velcro. Fortunately, the failure occured on the ground.

RE: Spektrum DX7 + AR7000 -> Total loss of signal
 

I was thinking this also...

RE: Spektrum DX7 + AR7000 -> Total loss of signal
 

Thanx for your comments....

1. The main rx and remote is mounted on a velcro which is isolated from the airplane body via foam used for receiver mounting. All the wiring is 2" away from the rx antenna. Took spl care of that.

2. I plugged back everything 5 mins after the crash and it was all working.

3. After the 1st landing, I checked the rx light and it was green.

4, Had about 25 flights on the direct 6.6v genuine A123 system and used an approx of 150 mah on avg per flight. IN fact i flew once earlier in the day and all was cool.

5. I have used this rx on other planes. It doesnt have the blinking system to indicate a brownout. Probably an older version but it does have quick connect. Ironical as it may sound but it was the quick connect feature which made me change my 72 mhz set up!!!

6. Ignition on my engine was an rcxcel from CH-Ignitions.

7. I did a range check after the first brownout with bind button pressed (motor not running) and walked out really far. All was well

8. I flew another of my planes ( a 90 sized mustang converted to electric running an AR 6200) and my Trex 500 heli (AR 7000) on whic i did some basic 3d stuff (current hungry digis on them) after the crash and all was well.

9. Both incidents happened at exactly the same spot over the ground, at the start of the loop.

10. The symptoms were of a lockout where from more or less neurtal positions, aileron and other servos moved to their extreme throws since the plane rolled into the ground at full throttle.

11. Many guys were using JR / Spektrum systems and no spot related problems.


Just need to get confidence in my radio system thats all. I thought the initial brownout/lockour probs were fixed...

RE: Spektrum DX7 + AR7000 -> Total loss of signal
 

cometravi - Did you notice the Throttle going to Idle as soon as you realized you did not have control of the aircraft? This would be a sure sign that the radio went into Failsafe.

When was the last time you went through the Bind Process? When you Bind the Tx to the Rx, it also sets up the Failsafe Conditions, and it should be done whenever you make any major changes to the programming.

Let's be correct on the terms.
A Brownout occurs when the voltage in the Rx drops below critical, usually due to a heavy current load on the Rx. If the connection to the Rx battery is faulty, you will experience a loss in power to the Rx. In both cases, the Rx will not go into Failsafe and the Throttle will not go to Idle. In both cases, the Rx Reboots. If the Rx firmware was updated, you would see a Blinking light indicating that a Brownout had occurred or that the battery power had been cycled.

When the signal from the Tx to the Rx is lost, you are losing the Link. When this happens, you have a Failsafe Event, the Throttle goes to Idle, and the other Control Surfaces Hold their positions. As a test, turn on the Tx and Rx. Check the movement of the servos by moving the Sticks. Turn off the Tx and watch what happens to the Throttle and each Control Surface.

If the Tx loses power and regains it again, it takes a much longer time for the Tx to reboot than it does for the Rx to reboot if it loses power. This happens occasionally.

It is a good idea to do Range Checks with the Gas Engine Off and again with it Running.

RE: Spektrum DX7 + AR7000 -> Total loss of signal
 

Did you have the main RX and the satellite RX mounted with the antennas on X and Y axis?

If the main RX is in the plane flat, so you can see the top of it, then those wires will be pointing to the sides of the plane. Or maybe even forwards and backwards, if you mounted the RX sideways (left to right inside the plane)

If thats how it was mounted, then the remote antenna need to be pointing UP and DOWN.

Main RX on X axis.

Remote on Y axis.

If you didn't do that, then I'm almost positive thats why you lost the plane.

Here's a few pictures to explain what I mean. The first 2 pictures would be the correct way to install the 2 RX's.

The last 2 pics would be the WRONG way to install.

Let's talk about the RIGHT way to mount the 2 RX's:
In the first picture, you can clearly see that the main RX has it's antenna pointing out on the horizontal (x) axis and the remote antenna are on the vertical (y) axis.

In the 2nd picture, again we see the main RX with it's antenna on the horizontal (x) axis and the remote antenna are barely visible on the vertical (y) axis because you can only see the top one and it's pointing right at you.

The 3rd pic is WRONG because BOTH antenna are on the HORIZONTAL (x) axis. Sure, they are 90 degrees to each other. But they are BOTH on the horizontal axis. This is WRONG WRONG WRONG. One antenna MUST be on the horizontal (x) axis and one MUST be on the VERTICAL (y) axis. PERIOD!! This is not open for debate. Thats how it is.

The 4th pic is also WRONG. Both antenna are on the HORIZONTAL (x) axis. WRONG. PERIOD!! Not open for debate.

You guys can laugh and giggle and call me stupid. Don't care.

One antenna on X axis.
One antenna on Y axis.

PERIOD

I know this because I installed my first Spectrum just like pic 3. It was a 75cc plane. I had about $3000 into the plane. It all looked okay on the ground checks. I walked off a couple hundred feet. Maybe even 400 feet? Had a spotter watching the plane. No problems. Even the first 4 or 5 flights... no problems.

Then on the 6th flight I decided to see how much vertical this baby had. Pulled back on the elevator and pointed the nose up. Pushed the throttle stick forward. Up she goes. 200 feet... 300 feet... 400 feet... still going... accelerating... 600 feet.... okay, I'm satisfied. It has unlimited vertical. Throttle back. Down elevator. Nose over. Pointed straight down at the ground with the throttle at idle. Isn't she pretty? Such a nice flying plane...... la la la blah blah blah..... okay thats close enough. Ease back on the elevator stick and pull her out to level. Hmmm, thats funny..... elevator seams a little squishy. Not really responding. Pull back some more on the stick. Still going straight down. Ground getting much bigger now. [X(] FULL ELEVATOR STICK!! [X(] Nuthin'.............. [sm=cry_smile.gif]

I was about to give up. Keep in mind, this thing was at least 600 feet high when I pointed the nose down again. How long does it take to lose the signal............ shut down.......... reboot.......... and finally catch?

About 580 feet.......... [sm=lol.gif][sm=lol.gif][sm=lol.gif]

My elevator finally caught. Plane leveled off and immediately started a low speed snap. I basically did whats called a "terminator" maneuver. A wall when pointing straight down. I romped the throttle and got some airspeed under the wings. Did a 180 degree turn and called out for an emergency landing. Landed safely and shut her down.

Wheeled her back to the pits. Removed the canopy. Me and 3 or 4 guys standing around scratching our heads. Whats that smell? "Rcpilot crapped his pants!! He needs a new set of underwear!" [:-]

We had no idea what was wrong. I started my range checks again. Seams normal.

Thats when our buddy Stewart walked over and asked what was wrong. I shrugged my shoulders, "I dunno. Locked up and I almost splattered it out there."

The guy took one look inside my plane and pointed at my remote RX, "There's your problem, right there. You got both RX antenna pointing out on the HORIZONTAL axis. Flip that remote RX 90 degrees so the antenna are pointing VERTICAL and that will fix it."

[X(]

So I did.

And I ranged checked it for about an hour with the motor off and also running.

Gathered my courage and flew it again. No problems. I even pulled the same maneuver again, just to see if it was really fixed. Haven't had a bit of problems since I changed how that RX was mounted.

RE: Spektrum DX7 + AR7000 -> Total loss of signal
 

Rcpilot and all readers,

I do not see anything wrong with pic #3.

Only pic #4 has both antennas in the same plane.

Now a question for all readers ___

What do you figure would be the best receiving antenna(s) configuration installed which way in the airplane?

Zor

RE: Spektrum DX7 + AR7000 -> Total loss of signal
 

Very good points on the antenna placement. Just a few notes to look at.

Picture #1 and #3 have the same path diversity and it is fine as drawn. There is no difference between what one would call a main receiver and a remote receiver. The difference between the two on the AR7000 is the "main receiver" as we call it is the one where you plug in all the servos.

Picture #2 is fine as well.

Picture #4 above is the no - no. All others will work fine.

Just an FYI, on anything that is 50cc or larger, most all of the Team Members use 9 channel receivers or larger to ensure a full level of path diversity using the 4 receiver program.

RE: Spektrum DX7 + AR7000 -> Total loss of signal
 

Well, you guys can say and do what ya want.

Pic 3 is how I had my plane setup at first and I almost lost it.

Having BOTH antenna on the horizontal axis is WRONG. Just because one is sideways or one is higher/lower in the plane doesn't make it right. If they are both horizontal..... then they are both horizontal. Thats WRONG.

I always mount one on the vertical axis and one on the horizontal axis. If you have a 2nd satellite, then mount it on a 45 degree angle - either way. More satellites is going to be better so orientation with the 2nd, 3rd or 4th satellite becomes less critical. But when you have one main RX and one satellite - one vertical and one horizontal.

RE: Spektrum DX7 + AR7000 -> Total loss of signal
 

Pic 3 is wrong because both antenna are horizontal. It doesn't matter if the satellite is 90 degrees to the main. They are both still on the horizontal axis.

RE: Spektrum DX7 + AR7000 -> Total loss of signal
 

:D

RE: Spektrum DX7 + AR7000 -> Total loss of signal
 

Pic 3 is how I had my plane setup at first and I almost lost it.
[/quote]

That is not difficult to explain.

Put the nose nearly vertical coming down as you stated ___the antenna to the right is now vertical and the antenna to the left is horizontal. Now rotate the airplane around it longitudinal axis so that the horizontal antenna point at you the pilot and have your transmitter antenna nearly horizontal.

That gives you a condition of minimum signal transfer.

Zor

RE: Spektrum DX7 + AR7000 -> Total loss of signal
 

But in pic 3 one is vertical and one is horizontal. Both are not horizontal as you say.

RE: Spektrum DX7 + AR7000 -> Total loss of signal
 

Thats a top view looking down from above. They are both horizontal.

RE: Spektrum DX7 + AR7000 -> Total loss of signal
 

That does not change my reasoning in post #20 .

Zor

RE: Spektrum DX7 + AR7000 -> Total loss of signal
 

http://www.youtube.com/watch?v=t8gQg...layer_embedded

:D I like JR. I don't care. I set mine up the way I like. You set yours up the way you want. I don't care. I like JR. :D

RE: Spektrum DX7 + AR7000 -> Total loss of signal
 

Rcpilot is correct. I also did not pick up on the fact that Pic #3 was a top view, with antennas for both Rx's in the same Horizontal axis. Only Pic #1 and Pic #2 are correct.

It would be more obvious if the Stabs and Wings were drawn in on Pic #3