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Old Oct 22, 2012, 01:14 PM
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well I don't think thats the problem Ken, cos I have fitted a heatsink to those 2 MOSFET'S and they are touching each other (cos of the heatsink that I made) and my heli still turns hard left/ right, and using the 3600mAH battery. My heli has a lot more lifting power, and forward flight using the 2 tail motors. the one at the rear spins counter clockwise, and the middle one spins clockwise... Now I have made a great learning heli before I try and fly my nitro one, so it's Grreeeattt..

Mike..

Hi Mike,
I’m just guessing and could be wrong, but I’m thinking that maybe the G.T factory changes that were done on some of the new version PCB boards could be making them work electrically differently than some of the other version PCB boards. When I bought my Qs8006-2 helicopter, its original PCB board only had (1) 207 IC soldered onto it in between the (2) motor connector sockets. (This particular PCB board I’m finding out now was the cause of the cutout problems on my 8006).

Now the new updated PCB board that I recently bought does have a few extra things added on it that I can see. (Note; it’s the PCB board I posted about in my post #574 and page 39 and #700 post on page 47 that had the MOSFET’s touching and I had to separate them so the helicopter would turn). I believe you posted awhile back showing a similar PCB board, but for some reason the MOSFET’s reacted differently on mine.

Here’s the main changes on the new board that I can see;

New board has (2) very thin green jumper wires factory soldered onto the top of the board,
New board had the center 207 IC replaced with a RZ2 MI,
New board has (1) 207 IC soldered in each place of where the motor connector sockets use to be. So there are now (2) 2071C’s soldered onto the updated boards.
Also the top wires of the (2) 207 IC’s and the RZ2 MI are all soldered together by the factory and they all each have one bottom wire soldered to the circuit board.
The new updated board that I have also came with no motor connector sockets soldered onto them, so I had to solder on the motor connector wires to the bottom of the board for the main motors to get power.

So I tend to think that unless the 8006 PCB boards have the above mentioned things added onto them, then most likely the PCB board is the older version. I’m also figuring that the updated board that I bought is most likely a quickie fix released by G.T Model, and probably any new helicopter’s being sold in the future will have a slight bigger PCB board on them so that the motor connector sockets are already soldered on them. I’m just guessing though.

By the way, its good to hear that the stock 8006 charger works well with your much larger Li-Po battery and that your 8006 gained power from the new battery. I too had found out awhile back that different makes of batteries can affect the power of the Qs helicopters. I once switched to a different battery on my 8005, and it gained about 25 percent more lifting thrust power and acceleration.
I too have been thinking about getting something a little bit bigger than the stock 8006 battery. I would like to get over 10 or more minutes flying time with the 8006.

Ray
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Old Oct 22, 2012, 01:37 PM
Ret. CH-46 Pilot USMC
United States, OH, Whitehouse
Joined May 2012
85 Posts
The green wires are jumpers.Sometimes during circuit layout, especially with multi-layered boards, a few tracks come up missing. Usually they are found out during production. Instead of trashing a bunch of defective boards at a loss, the missing tracks are added in the form of jumpers.


Also, did some checking...the MOSFETS on the 8006 board are 150N03 TO-220 n channel MOSFETS rated at 150 Amps at 30 vdc running in enhanced mode. No need to upgrade as the current properties do not come close to exceeding the parameters of the existing MOSFETS. data sheets available...

Typical parameters for the main motors 380's

Rated Voltage: 11.1V
No load speed: 36000rpm
No load current: 1.31A

At Max Efficiency

Speed: 30453rpm
Current: 7.19A
Torque: 15.11mNm
Output: 48.19W

At Stall

Current: 39.5A
Torque: 98.1mNm

So at max voltage with the motor held at no rpm's the current draw is just under 40 amps per motor. For grins and haha's I placed a jumper across both tabs on my 8006 and got similar results as you did.
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Old Oct 22, 2012, 02:12 PM
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Originally Posted by helicrapter View Post
Hey ray, thanks for the update.

I actually fixed the balance of it by removing the little foam donuts on the rear landing gear and moving them all the way to the rear plastic tips. I secured them with hot glue and it seems to keep it from tipping back, even without the battery in place. It seemed to balance in the air fine before this fix.. but it's easier to take off and land when she's sitting level.

Hi helicrapter
That's a really easy solution fix for the helicopter leaning back problem. The helicopter will no doubt takeoff much better sitting that way.

Ray
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Old Oct 22, 2012, 02:26 PM
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Originally Posted by boulier1 View Post
The green wires are jumpers.Sometimes during circuit layout, especially with multi-layered boards, a few tracks come up missing. Usually they are found out during production. Instead of trashing a bunch of defective boards at a loss, the missing tracks are added in the form of jumpers.
Hi Boulier,
Thanks for the input on those little green jumper wires. I am kind of hoping that G.T Model doesn't consider those little green hair thin wires as a permant fill in or fix, because those little wires sure look very fragile and look like they could break easily if exposed to too much helicopter vibration.

Ray
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Old Oct 22, 2012, 02:55 PM
Ret. CH-46 Pilot USMC
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Originally Posted by Pilot Ray View Post
Hi Boulier,
Thanks for the input on those little green jumper wires. I am kind of hoping that G.T Model doesn't consider those little green hair thin wires as a permant fill in or fix, because those little wires sure look very fragile and look like they could break easily if exposed to too much helicopter vibration.

Ray
Haven't got that close a look, but if wire is stranded, a drop from a hot glue gun should suffice to hold them in place, if the wire is solid I would use more then a drop.....
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Old Oct 22, 2012, 04:29 PM
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Originally Posted by boulier1 View Post
Apples and oranges Ken my friend. . .... there are endless options depending how devious you are....lol
more later....keep the questions coming....take care
Hi boulier1,
Thanks for the info,
You were right about the glob of solder although removing it hasn't made any apparent difference to the PCBs operation. You've better eyes than me, I had totally missed it. The red PCB indicator still cuts off about one second after power is turned on. Other PCBs I have, including the 8006s, all stay on until bound to the TX. The rainbow colored stuff is scan glare.
I had figured that signal coding would be part of the overall picture but also figured that with the tendency for the Chinese manufacturers to copy it was worth a shot.
My preferred option has been to make use of the original 8006 PCB to avoid adding weight. I still have the option of using the tail rotor power supply but this has its own drawbacks, although I might have to go down this road even if just to prove whether the theory can be borne out in practice.
cheers mate,
Ken
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Old Oct 22, 2012, 04:52 PM
Ret. CH-46 Pilot USMC
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The thing to do is get the right x-mitter for that receiver then get it to bind, then test the pins of the IC while operating the x-mitter, a scope and dvm would be nice. I still think there are extra channels...there are 6 unused pins and 3 channel is odd...
I would almost bet it's a 4 channel chip
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Old Oct 22, 2012, 05:19 PM
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Originally Posted by boulier1 View Post
The thing to do is get the right x-mitter for that receiver then get it to bind, then test the pins of the IC while operating the x-mitter, a scope and dvm would be nice. I still think there are extra channels...there are 6 unused pins and 3 channel is odd...
I would almost bet it's a 4 channel chip
Hi boulier1,
It would be so much simpler if I could find the control feed to the 882s and work from there. I'm trying to work with the original 8006 bits as much as I can rather than completely rebuild a heli otherwise I'd be better off just buying a heli that "works". There's some nice BIG stuff out there for around a couple of k.
Current thinking is a reversible 12 volt motor/gearbox running off the tail rotor power supply. Keeps to the original 8006 PCB and TX and the only negative I can see is not being able to determine where "hover/neutral" position is. Still, should do for testing purposes. Worst case scenario, I have heaps of spare parts.
Ken
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Old Oct 23, 2012, 01:50 AM
Ret. CH-46 Pilot USMC
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Disconnect the tail rotor motor from PCB, put dvm on PCB connector to tail motor, now turn it on and ascertain the voltage levels by operating the x-mitter. You should see a positive voltage swing in one direction and a negative swing in the other. Using a differential op-amp you can use the output of the op-amp to drive most anything...
And if you can find the parameters for the tail motor then you now have the degree of voltage swing along with the current requirements and can build from there.
I would think it would be easier to use the existing signal to the tail rotor as a driver because the controls are already in place.
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Old Oct 23, 2012, 05:14 AM
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Originally Posted by boulier1 View Post
Disconnect the tail rotor motor from PCB, put dvm on PCB connector to tail motor, now turn it on and ascertain the voltage levels by operating the x-mitter. You should see a positive voltage swing in one direction and a negative swing in the other. Using a differential op-amp you can use the output of the op-amp to drive most anything...
And if you can find the parameters for the tail motor then you now have the degree of voltage swing along with the current requirements and can build from there.
I would think it would be easier to use the existing signal to the tail rotor as a driver because the controls are already in place.
Tail rotor pins voltage checks: Two 27M PCBs & two 27M TXs.
Both PCBs stock standard as delivered. Old type with main motor pins, no green jumper leads. No 882 or other mods. TXs new batteries.
Test conditions:
PCBs connected to original 14.8 volt battery. Only a dvm connected to tail rotor pins, no motors or LEDs. Once RX/TX bind throttle set mid way.
First PCB.
Control very slowly eased forward until a voltage first registers on dvm. -16.44 volts. (with control full on, little difference)
Control very slowly eased back until a voltage first registers on dvm. +16.44 volts. (with control full on, little difference)
Same result with both TXs.
Second PCB.
Control very slowly eased forward until a voltage first registers on dvm. -14.40 volts. (with control full on, little difference)
Control very slowly eased back until a voltage first registers on dvm. +0.67 volts. (with control full on, little difference)
Same result with both TXs.
I give up!
Ken
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Old Oct 23, 2012, 07:36 AM
Ret. CH-46 Pilot USMC
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Joined May 2012
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Measure resistance across motor leads, then use that to check current draw under same test parameters....

And don't give up...it's just getting interesting


Other news...output transistor on x-mitter 5609C... hfe (dc current gain) is 60 at 2vdc, minimum 180 at 10 vdc, max hfe 340, transistor rated at 10-30vdc depending on manufacturer.
My x-mitter runs 6 AA @ 9vdc...see where this leads? The chips on it are run from a 78L05 +5vdc regulator max input.....ready....30vdc
the x-mitter is powered at 1/3 it's capacity...

more to com....
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Old Oct 23, 2012, 04:05 PM
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Originally Posted by boulier1 View Post
Measure resistance across motor leads, then use that to check current draw under same test parameters....

And don't give up...it's just getting interesting


more to com....
Hi boulier1,
With very little of my flying done backwards except when facing into a slight breeze it's probable that the second PCB has had that voltage difference from the get go and I just never noticed it.
I thought that the voltage increased as the stick was moved forward thus increasing motor speed. Too late now but I'm wishing I'd stuck with electronics after my apprenticeship.
Ken
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Old Oct 23, 2012, 07:01 PM
Ret. CH-46 Pilot USMC
United States, OH, Whitehouse
Joined May 2012
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The motors need 2 things to run.....current and voltage. MOSFETS can be used to control both... see where that is leading my friend... check current under load, the motor, put ammeter and dvm on and watch....
Now....since it has been a while, and I have slept since then is this about adding twin tail rotors? Can we make a set of main rotor blades work on the tail?

Is there another motor with higher rpm?
What is the tail rotor motor?
Do you have it's parameters?
Can the gears be changed?
Can a different prop with a more aggressive angle of attack be used?
In it's basic form the problem is how to generate enough air flow to keep the nose down....


The difference in the second board, did it have the newer transistors? When you remove them, could you test the hfe, just curious.
Do you have a scope? A curve tracer would be real handy...
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Old Oct 23, 2012, 09:56 PM
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Hi everyone,
Well wouldn’t you know it on the 8th flight my Qs8006 helicopter had its first power cutout with the new PCB board. Fortunately the helicopter was up about 30 feet and had time to recover from the lengthy 1 - 2 second cutout.

Then for the 9th flight, I decided to take the antenna wire from the old PCB board and added it to the antenna wire on the new PCB board and then ran the extra long antenna straight back to the tail support and then back forward about ½ way so as to use up the left over part of extra long antenna wire. I also went on ahead and eliminated the ON / OFF switch just incase maybe it was causing the cutout problem.

Then I took my 8006 out for its 9th flight and everything was going smoothly until about the half way point, and then my 8006 again did one of those random power cutouts lasting for around 1-2 seconds. This time the helicopter was only up about 20 feet and it barely recovered and came very close to hitting the ground, but the helicopter recovered just in time.

I want to mention too that in both instances my 8006 was no more than 50 feet away when the power cutout and the transmitter batteries were well charged and not low on power.


So I have now come to the conclusion that for some reason my Qs8006 helicopter’s is suffering from some sort of interference that momentary causes the transmitter to unbind from the 8006’s receiver. I have no idea why my 8006’s radio system is so sensitive when compared to my other RC radio systems, but it is.
I'm not sure why the 8006 would act this way since my flying area is out in the country and I am flying next to farmland by my house, and none of my other RC airplanes don’t have this power cutout issue.

So all I can say is that this power cutout issue is very frustrating and I have lost all confidence in flying my 8006 helicopter reliably.

I will keep flying my Qs8006 until the next big cutout that causes heavy crash damage, then I will shelve my 8006 until I can find a new radio system that will work reliably on the 8006 or until when G.T Model makes a new radio system available for the 8006.

I haven’t given up yet, but I must say this is a very frustrating and heart stopping problem, especially when it happens without warning on a helicopter.

Ray
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Old Oct 24, 2012, 04:19 AM
Ret. CH-46 Pilot USMC
United States, OH, Whitehouse
Joined May 2012
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Originally Posted by Trainee Ken View Post
Hi boulier1,
I thought that the voltage increased as the stick was moved forward thus increasing motor speed. Too late now but I'm wishing I'd stuck with electronics after my apprenticeship.
Ken
It does...but the change is faster (real time) then the response time of your meter,with a scope you could see it.

All good, you got what I thought you would, another piece of the puzzle in place, thank you so much for your time and effort.

We are moving forward....albiet slowly...
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