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Mikado Modellhubschrauber . GrandRC . CanoMod

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Align T-REX 600N 700N > DS8717 and 2in1 regulator Align... PROBLEMS???
 
 
d_adam
Heliman
Location: Bytom, Poland

Hi.
I hava a few questions…
I have 2in1 regulator Align in my T-rex600Nitro, 3x DS8717 servos, DS8900G with G770 and HS635 on throttle. My battery is Flight Power RX 1320mAh.
After 1 flight I charge only about 300mAh… (8 minutes 3D light flight)
My question is:
How many amperes take it?
This regulator has got 6A..
When I made chaos, few seconds later my helicopter was turned very hard (slow)
I think it wasn’t disturbance…

Anyone flying on 8717 and 2in1 Align?
Thanks.

Best regards,
Adam.
03-15-2008 08:13 PM
 
 
Simmer
Key Veteran
Location: Massachusetts

your battery seems to be a little on the small side. 1900 min I would think. I have three 8717s on my trex and I run a 2600 Lion battery.

Not sure on the align 2in1 as I dont own one.


Your telling us you used 300mah on the one flight. Thats about what I am seeing also. I know two people flying the 8717 with a the align 2in1 but they are using a 2100mah FP Evo battery (20 or 25C not sure)
03-15-2008 08:22 PM
 
 
Simmer
Key Veteran
Location: Massachusetts

But.... if you have resistance on the servos, like ball links tight, they will draw more power. Make sure they are feee enough!
03-15-2008 08:28 PM
 
 
d_adam
Heliman
Location: Bytom, Poland

Simmer,
thanks for reply.
My ball links are OK.
What have you regulator??


I think. 1320 or 1900 or 2100 isnt important... I can do 2 flight only. No problem, but I want to know how many ampers 8717 take...


Sorry for my English
03-15-2008 09:10 PM
 
 
Hanson
Heliman
Location: Poland SILESIA

the same question..
what is ampdraw of 3 8717 servos under load ?
anyone flying with ALIGN B6T 2in1 regulator/8717 ?
03-15-2008 09:27 PM
 
 
Simmer
Key Veteran
Location: Massachusetts

the amperage draw will be effected by load. I personally do not think its the 8717s While the draw could be as high as 5amps momentarily, 9252s will do this also. Your right about the size not being important. I have an Arizona regulator. I run a LithIon 2600. I consume 300mAh per flight. No issues here, but I am sure I am not loading up my ship. (no hard 3d). I know a LithPoly can handle a higher load,(than my LithIon) but Im saying I doubt its the 8717s.

Although you will find several/many who will tell you thats the issue.

Here is why I think this:

RChover is a buddy of mine and he has run the 1900 Align Lipo with three 8717s on a 2in1 @ 6 (and 8 volts) The other guy who works with him at the shop runs the same setup on 8 volts. Same 2in1 same 8717s same Align 1900 battery, and no issue. These guys fly very smooth but very hard 3D.

Your regulator could be bad, maybe intermittant.

(watch the firestorm start now but check and see if they actually own the 8717s )

If you think your drawing more current than the reg can handle then put on a battery/voltage monitor and check it after the flight. Sparten has a real nice one for 64.00 and the Gem2000 is another you can use to help isolate this type of issue.
\
Sorry for the rant, I am soo tired of people claiming these servos are the root of all evil. Most just dont even own them and critisize based on others who coment without actually owning them.\\\

One more thing I will repeat. If the load goes up, if you have binding the current draw WILL go up. But under normal use, three servos sharing the load, no binding, you should be undr the limit of your 2in1. Did you overthrow collective and cyclic at the time you saw the issue? Are you sure your links are fee enough? This is a very important factor
03-16-2008 02:20 AM
 
 
tracvision
Senior Heliman
Location: Tampa, Florida

original 2 in 1 or new style

I had the same issue wit the original 2 in 1. I changed to the new style with the enclosed case and the problem went away.
03-16-2008 02:24 AM
 
 
Simmer
Key Veteran
Location: Massachusetts

A google search turned up this from Ron Lund,

Quote 
It would depend on your flying style and your setup. Typically, there wouldn't be any problem, however, if you have any of your servos or linkages in a bind, the amperage goes up dramatically.

After you get the heli built, try this. Unplug the regulated power to the receiver. Power the receiver with a 4.8v NiCd battery by just plugging it directly into the receiever. Also plug a voltage monitor into the receiver.

Using the transmitter, move each servo to it's limit. The voltage should be the same when the servo reaches the end of it's travel. If the voltage drops, back off the travel limit a little and check again. Do this with each servo.

If you go for a really wild setup, you can expect some binding if you move the cyclic stick into the corners at full positive/negative . I wouldn't worry too much about that.
03-16-2008 02:28 AM
 
 
Simmer
Key Veteran
Location: Massachusetts

And this from the same thread.

Quote 
Hello All- I run the same setup and the most I can get it to draw is 8 amps that is if I hold the swash still and jam on the sticks. I am currently running the 2in1 and 8717's with the 7703d and matching servo. unloaded and jammingh on the sticks i am pulling around 3.5 amps. hope this helps!!
D
03-16-2008 02:31 AM
 
 
Kona Chopper
Veteran
Location: Kailua-Kona, Hawaii USA

I read this early about the amp draw from 8717. http://www.castlecreations.com/supp..._advisory1.html



Why buy when you can borrow!!
03-16-2008 02:43 AM
 
 
Simmer
Key Veteran
Location: Massachusetts

cool, but you have to ask then, what was the load? How was it tested?

The guy stated above he held the swash (as if it was binded up)and got it to go up to 8amps (binded)

And finally, why are so many folks running them with all the extra things, gyro, throttle, governor, with no issues?

There is static tests and there are real life tests. I suspect they are at times running close to the limit of the 6amps, maybe, but it just cant be like that spec sheet in real life, or everyone would be dropping thier helis out of the sky.

I emailed JR, and I will post the reply if/when I get one.

Me personally, there is not a fatser or more powerful servo on the market. I will take this small risk as I tend to take as many extra precautions I can when I fly anyway.
03-16-2008 03:12 AM
 
 
MJWS
Key Veteran
Location: Airdrie, AB - Canada

If you run for 8 minutes and replace 300mah your current is 2.25A on average. No real way to know what the peaks are without measuring, but we know a stalled 8717 can pull a bunch. Maybe enough to brown out a spektrum rx, or just choke momentarily. There are others running the 2in1 on these servos. Doesn't leave enough headroom to make me comfortable.

The small pack is a non issue and easily capable of the loads for a couple flights.

Mike
03-16-2008 03:18 AM
 
 
Kona Chopper
Veteran
Location: Kailua-Kona, Hawaii USA

Anyone know what alan jr.'s 600N set up is using these servos?



Why buy when you can borrow!!
03-16-2008 03:21 AM
 
 
Simmer
Key Veteran
Location: Massachusetts

A stalled anything can pull a bunch A Stalled 8717 will pull more I'll give you that.

Either way your pushing your current draw up with a stalled servo.

Don't run them if your uncomfortable but this still does not explain why no wide spread failures.
03-16-2008 03:23 AM
 
 
Ozydego
Key Veteran
Location: Westerville, Ohio

I fly the 2 in 1 regulator with 4 8717's, (one on the throttle as well). I also use the 7703d with the 8900G servo. I use a TP 2100mah battery and get a good 5 flights on a charge. I am using one of the original 2 in 1's and I do not have any issues. Also, this is all on a JR PCM radio.

Does anyone know the max amperage output the 2 in 1 can sustain??

But Honey, I can't live with just stock.....
03-16-2008 03:26 AM
 
 
Simmer
Key Veteran
Location: Massachusetts

Here is the spec on the Arizona regulator.
http://www.fromeco.org/Products/02F...00/Default.aspx
Not sure I know how to read this.

Quote 
Translating Power
The Arizona Regulator is rated in Watts, because the current limit moves, based on load. These limits are affected by battery voltage "droop" as it is loaded, and the voltage setpoint of the adjustable output. Current limits are shown to the left (based on power)*, for a regulator with the adjustable voltage at 6V (red), 5.5V (pink), and 5.0V (purple). Note that the higher output voltage means the regulator does not have to work as hard, and therefore the current limits are higher.
03-16-2008 03:32 AM
 
 
MJWS
Key Veteran
Location: Airdrie, AB - Canada

Heh. It's the 2in1 not the 8717's that makes me uncomfortable. Not sure why you're under the impression that people think they are they devil, Simmer. There isn't a servo out there that is close.

Not sure why someone hasn't load tested the 2in1 and published it. It would need to be accurate enough to see the extremely short duration spikes down that can crash spektrum to be really useful. But even just... it overheats after 30 seconds @ 5A would be a start.

The other reason you don't see many failures is many run the 8717's direct. That is why they got them in the first place.

Mike
03-16-2008 04:18 AM
 
 
MJWS
Key Veteran
Location: Airdrie, AB - Canada

Heh. Found the thread slaggin on the 8717's. Hilarious. Missed that one. You have to consider the source on much of that commentary.

Mike
03-16-2008 04:29 AM
 
 
Simmer
Key Veteran
Location: Massachusetts

Yes sorry I was ranting, root of all evil, I just have read over and over "those servos draw too much power"

I cant find specs on the 2in1 other than the 6Amp max rating.

Running direct sounds feasable but, all electronics must run at 7.4 votls then, and as the battery gets lower, the servo characteristics would change.

I bought mine because they were real fast, and could go up to 6 volts. Is there a receiver that can run on 7.4 volts? or are they using a separate regulator for the reciever?
03-16-2008 04:30 AM
 
 
Kona Chopper
Veteran
Location: Kailua-Kona, Hawaii USA

http://www.runryder.com/helicopter/t416086p1/
About using 8717's staight of the lipo.



Why buy when you can borrow!!
03-16-2008 04:34 AM
 
 
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Align T-REX 600N 700N > DS8717 and 2in1 regulator Align... PROBLEMS???
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