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A Main Hobbies . Boca Bearings . Modefo's RC Helicopters

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Audacity Models Pantera 50 - Tiger 50 > PANTERA ISSUES.
 
 
kalps
New Heliman
Location: melbourne. australia

Hi,

I got a pantera in Jan. It was ARF kit. I use a DX7 radio. I put the kit together as per the manual. Being an beginner my instructor tried taking it up for a test flight. Within 40 secs of hover, she took off on its own did a back flip and crashed. We thought it was the battery or the AR7000 receiver. I transfered the radio gear, servos and battery to a raptor. Found no issues. After 3 months, i put the pantera back, not to mention a hole in the wallet replacing the parts. Back on the field yesterday, another instructor took it up and within a min of hover, she flips front and crashes. Not too much damage this time. Just main blades and all 3 shafts(main, spindle and tail)and arm. Is it my luck with this model or what? The setup was done at a begiiners level by someone who has been flying for over 35 years. Please help, i am getting to a point to bin the bloody thing.

Very Disaapointed,
Kalps.
04-07-2008 03:33 AM
 
 
Eury
Elite Veteran
Location: Ankeny, IA, USA.

That sucks, but honestly, I don't see how It could be the heli. The only thing in the heli I can think of is to look at the linkage and lever for the elevator. Most likely, you have an intermittent fault with the elevator servos. I'd bet on it in fact. Sometimes youncan make a servo that has a problem freak out by touching a running Dremel to the case. The vibration and electrical fields can expose things like bad solder joints.


Nick Crego
As I wind on down the road...
04-07-2008 03:43 AM
 
 
kalps
New Heliman
Location: melbourne. australia

hi,

Thanks for that. After the first crash. i put in all new servos. New AR7000 receiver. I was using servos which came with the DX7 radio, but changed them to hitec 6635h digital servos, with JR 77ot gyro. I will not blame the radio gear, cause it's all brand new.
04-07-2008 04:01 AM
 
 
Eury
Elite Veteran
Location: Ankeny, IA, USA.

Ok, that gives us something to go on. If it was the problem or not, the servos that came with the Dx 7 weren't good for the heli, Horizon even has a notice that they will fail in 50 sized helis and say not to use them.

So that leaves us with what's left. How's the switch? After you got it all setup, did you rebind the receiver? What battery are you using? If you turn on the heli without the radio on, what do the servos do? Do they go to a position where the heli would flip like it did?

If it's mechanical, it has to be in the elevator linkage. When you went to pick up the pieces were the elevator links still connected? If everything is connected and you remove the link from the elevator servo and hold the awash so it can't move, can you move the link that you pulled from the servo?


Nick Crego
As I wind on down the road...
04-07-2008 04:11 AM
 
 
kalps
New Heliman
Location: melbourne. australia

Hi,

I am using a sanyo sub c 2400 battery pack. I got a new JR switch with gold pins on it. From the crash i gathered. From the crash i gathered the ball was on the elevator ball link.
04-07-2008 04:20 AM
 
 
Eury
Elite Veteran
Location: Ankeny, IA, USA.

Check where the servos go when you turn on the heli without the radio on, and how the physical connections are between the servo and the awash.


Nick Crego
As I wind on down the road...
04-07-2008 04:28 AM
 
 
kalps
New Heliman
Location: melbourne. australia

hi,

Sorry, i dont understand that. what will that exercise prove. If you may kindly explain
04-07-2008 04:38 AM
 
 
Zaneman007
Key Veteran
Location: Texas - USA

Maybe you had a brown out on the Rx.

Switching the electronics from a eCCPM machine to a mechanical mix machine will not simulate the same current draws. You are comparing apples to oranges.

Until recently spectrum Rx's were having "brown outs". If the current went below a specific voltage the Rx would reset, a three second (no input allowed) process.

Maybe the "Sub C" pack may be the cause of the problems?

Summary:
The issue does not sound like a Heli related issue.

I'd rather be flying
04-07-2008 04:40 AM
 
 
Eury
Elite Veteran
Location: Ankeny, IA, USA.

The Spektrum system has a fail safe that drives the servos to a preset position that is set when you bind. That's why the manual tells you to rebind after you set everything up.

What you are describing is exactly what would happen if you bound a receiver with the awash set to the default 90deg, then later set it to 120 for the Pantera and never rebound it.


Nick Crego
As I wind on down the road...
04-07-2008 04:44 AM
 
 
kalps
New Heliman
Location: melbourne. australia

Thanks guys. What i was think was to strip the whole head and rebuilt it. It was an ARF kit. Some of the nuts and bolts are quite loose. Most likely will be ready for flight next weekend. I will not blade the battery. I was using the same battery pack with an AR7000 on my raptor.
04-07-2008 04:53 AM
 
 
kalps
New Heliman
Location: melbourne. australia

I have to admit. i did not re-bind after the setup.
04-07-2008 04:54 AM
 
 
Eury
Elite Veteran
Location: Ankeny, IA, USA.

If you do check it like I said by just turning the heli on, you can check where the bind position is. I'd bet that's what caused it to flip, and the fact that it flipped in opposite directions the 2 times is because the direction of rotation between the JR/Spektrum servos you first used is opposite the direction of the Hitecs. It doesn't explain why it went into failsafe, but it does explain the final effect. I'm going to bed now, try the test and report back and we'll work out the cause after I wake up.


Nick Crego
As I wind on down the road...
04-07-2008 05:00 AM
 
 
Heli_Man_Bob
Heliman
Location: Miamisburg, Ohio, US

What zaneman007 is saying about the current draw is true you may not be comparring apples to apples 120Deg swash vs 90deg One uses one servo for coletive input the other uses three at once.

Have you bench tested just how well this battery will last on the bench example moving both sticks to fullest working all servos at once to see when time duration) the voltage will drop to the point that the rec will cut out due to low voltage. You may be suprised at how quick this can happen with a standard flight pack especialy the one that came with the DX7 wouldnt last 5 min on the bench in a raptor.

New heli everything a little tight not broken in yet = drawing more current. Its all adding up.

Hope you find your issue on the bench instead of in the air.
04-07-2008 05:55 PM
 
 
jbeech
rrAdvertiser
Location: Sanford, FL (Orlando area)

I'm glad to have you guys helping Kalp while I am away visiting my Mother. He also posted on technical forum of our website and I am gratified to see the experienced crowd here pretty much following my train of thought. Here's part of what I answered peviously . . .

"It's kind of hard to diagnose a problem like you've described. Frankly, it really doesn't seem to have anything to do with the brand of helicopter as what you're describing seems to be a radio related issue, i.e. it may well do the same whether it's a Pantera, Raptor, Sceadu, 600N, etc."

Anyway Kalp, it seems like this crowd has a good handle on the issue and a solution will appear. If it doesn't turn out to be the binding, or the brownout issue (which is one reason I personally prefer Futaba's FASST solution for 2.4GHz), other things to consider are the extensions you are using.

I.e. make sure the extensions are gold plated, heavy duty, and working. The tip about touching an operating Dremel tool is a great one for troubleshooting. Also, don't forget the governor (if you're using one). I nearly went nuts with a glitch, which lead to crashing twice before my pal Rodney Shatera figured out I had a problem with the sensor wire leading to the main box of the Futaba GV1, which I had completely overlooked.

Hang in there, you've got a good bunch looking out for you!


John Beech - GM (and janitor)
Audacity Models
04-07-2008 06:29 PM
 
 
kalps
New Heliman
Location: melbourne. australia

Thanks guys, i really appreciate it. I am waiting for the parts. i will let you know how i am going.
04-07-2008 09:58 PM
 
 
billrad
Senior Heliman
Location: Rineyville, KY

Hate to hear about anyone crashing.

My experience is that, unless you can point to a part and easily see that it failed, it's electronics or battery every time.

I had a bad sub c nicad once. Horizontally it was a 4 cell, but rotate it vertically, and it became a 3 cell.

I had a receiver that, if you pushed on it in the center, just quit.

I took off once in heading hold. The problem was, it wasn't programmed in my transmitter properly. Of course, the heli knew this, and responded accordingly...

Billrad

I may not be able to turn a kit into a plane, but I can turn a plane into a kit...
04-07-2008 11:29 PM
HOMEPAGE  
 
 
billm
Key Veteran
Location: Liberty Lake, WA

Spektrum is aware of the brown out problem. If you have an older unit they will reprogram the firmware to fix the problem. The old firmware will go into fail safe when the input power drops below a defined voltage. The new firmware is written to wait a few moments before it kicks into fail safe. This allows for the momentary loads from servos sucking the voltage down. If you noticed in some of the LHS you can get a little capacitor (10uF) with a connector to help solve the problem. I pump a regulated 6v to the rx to avoid this problem.
my 2 cents.

My name is Billm. Cough, and I'm a Heli Holic
04-09-2008 02:46 AM
 
 
pertti
Heliman
Location: deltona,FL

Had a similar issue with a Jr 72MHz radio and Jr 4500maH nimh battery. Heli sporadically locked out. With LiIon + regulator all the problems disappeared.
04-09-2008 03:33 AM
 
 
billm
Key Veteran
Location: Liberty Lake, WA

You had problems when using 72meg? Wow thats something I never had happen to me. Nice to know you pumped things up. Could you expand on your post? Did you run PCM on 72?

My name is Billm. Cough, and I'm a Heli Holic
04-11-2008 03:41 AM
 
 
pertti
Heliman
Location: deltona,FL

Bill,
I use JR7202 tx and R790 scanselect PCM receiver (synthesized, no xtals), Hitec 5475hb digital "standard servos", GV1, tail is gy401 with s9254 servo. Used JR extra 4500mAh Ni-MH battery. Battery connected thru power on/off switch to the radio. Leads from battery to switch to radio were pretty long. This setup did scary things. Now the interesting part - replaced the battery with lipo and added "low cost" Align BCE b3x regulator that runs "6V" except to tail thru second regulator to give 9254 lower 5.1V. Removed the power on/off switch, i.e lipo directly to the bce regulator that has its internal switch. Tested the original setup with nimh using futaba br-2000 battery tester and got 4.4V@2A and less when loading with 3A while regulator delivers steady 5.5V. The spec says 5.8V but reality from this one is 5.4-5.5V @ 3 amps.
04-11-2008 05:32 AM
 
 
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Audacity Models Pantera 50 - Tiger 50 > PANTERA ISSUES.
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