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Old Aug 23, 2014, 04:26 PM
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Your card? I just paid off my truck! DON'T TELL THE TRUCK!!
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Old Aug 23, 2014, 04:29 PM
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Quote:
Originally Posted by IntegrityHndywrk View Post
I do run just a straight unregulated 2S on my X7. I haven't ever had any problems. There shouldn't be any danger with running a 2S lipo direct to your system unless your servos or something can't handle the fully charged 8.4v. Otherwise, the worst possible danger is if the lipo isn't in good shape and voltage sags enough to brown out. But a new, good condition lipo shouldn't sag enough to cause a brown out unless your servos are pulling an incredible amount of current. A 20C 1500mAh lipo is capable supplying a constant 30A (1500 x 20 = 30A). Chances are you have some kind of bigger problem if your pulling a constant 30A with your servos in flight.

Well now I am just guessing.
I don't see anything in print about my Savox HV servos being able to handle 8.4 volts. None of the timing or torque specs go higher than 7.4.

How is the safe maximum voltage determined?
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Old Aug 23, 2014, 06:30 PM
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Originally Posted by A VIKING View Post
Well now I am just guessing.
I don't see anything in print about my Savox HV servos being able to handle 8.4 volts. None of the timing or torque specs go higher than 7.4.

How is the safe maximum voltage determined?
Not sure with all the variables? Much the reason again I settled on something I can control. I also tried the dedicated flight packs that limit the voltage under 7 no matter what. Those exibited the fastest draw down and shortest or lowest flight voltage numbers of any packs I played with over the years. Those ended up finding their way into the land fill. But a guy I fly with uses those on his 600 compass with Savox servos and until this last year didn't have any issues. But on his 7HV, it has crashed two or three times this year alone doing strange things.

Oddly when we were setting up the Kontronic esc last week, I noticed its own high end bec won't output anything over 8v. So for $800 you may get the only esc out there with a bec that may (?) be reliable. Yet it can't fully power the higher voltage servos. I read a rash of early posts with guys having bec failures with them early on. But nothing lately. My god, $800 for just one esc? Even my own fleet uses second hand Yge's I carefully bought on the cheap. Guess if I was making 100k a year it wouldn't matter
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Old Aug 24, 2014, 02:52 AM
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Yeah, I've heard those BD gyros have a bad problem with brownouts. I'm pretty sure the BeastX, SK, Vbar, Ikon, MSH and other gyros aren't as sensitive far as i know.

Viking, I know some brands rate their HV servos at 8.4v and others at 7.4v. I'm fairly sure that if they are HV servos that are rated at 7.4v. Then they are probably fine to operate at 8.4V with a lipo because the operational voltage will be lower under load than the no load max charge voltage, but it would't hurt to find someone who has done it. 1v isn't a huge difference that i would worry about. I know I've read about some people who run servos rated for 6v at 7.4 and claim to not have problems. I'll bet if you look around the web you'll find people using a straight lipo with your servos. What model servos are you using? Have you checked the mfg. website? Some of them say in the online description "Special design for high voltage native 2s LiPo operation." but only have a spec listed for up to 7.4v operation. I'm sure they wouldn't do that if it wasn't safe to do.

http://www.savoxusa.com/Savox_SV1270...avsv1270tg.htm

While operating under load, the voltage of a lipo will drop. So a fully charged lipo might only be around 7.4v while flying. I've heard that Savox servos have a high current draw. If that is the case, then the voltage will drop a decent amount from just being powered on and holding the control surfaces idle. While flying 3D it will likely drop as low as 7.4 volts with a fully charged pack and probably go lower as the pack depletes. The no load voltage on my 1500mAh packs after 3 flights is something like 3.7-3.8v/cell. So lets say best case, by the end of the 3rd flight. The no load voltage of my RX pack is 3.8v/cell or 7.6v. We can obviously assume that during the last flight the voltage likely dropped well below 7v at some time. Probably dipping as low as 5.8v. I know some people use large 2000mAh RX packs and fly 3-4 flights on them before charging/swapping, but i prefer to just carry 2-3 1500mAh packs and switch them out with my flight packs. Because they are light and easier to place for CG. I mean, how many flight packs or flights in a day are you going to have anyway, and is it that hard to just charge the RX pack at the same time for the 5-10 minutes that it takes?

Like LMH mentioned, using a regulator keeps the voltage.... well... Regulated.. That obviously keeps the servos performing more regularly due to less fluctuation in voltage. But it also means it is driving the servos harder all the time. I wouldn't go as far as saying the servos won't last as long being regulated. But they may run hotter, which is something i like to consider here in Florida. There is also the possibility of the regulator failing which could just black out, or it could pass the 3S lipo voltage through and fry stuff. But that really is a random chance thing that does happen to some people. But isn't very common. I think most people feel perfectly safe with regulator setups as well.

Like i said, this is a thing that people debate all the time. I don't think there is a right way or a wrong way. I'd probably be happy with either one.
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Old Aug 24, 2014, 03:26 AM
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Thanks Integrity!
For cyclic I am running Savox SC1268SG which does state in the description they can be run with unregulated lipos.
For the tail I am running a Savox SB2272MG which is HV also but they do not have the same statement in the description about the use of a unregulated lipo.

I'll try to contact them and ask if it is ok for the tail servo to unregulated.
I am almost positive it will be ok and the first flight will be nothing but pitch pumps and pirouettes and then a check of the reported buss voltage from the SK.
The buss voltage from the CC Pro BEC never changed more than a tenth of a volt when being beaten, it worked well.

Thanks for all the great info, I appreciate it.
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Old Aug 24, 2014, 08:33 AM
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Originally Posted by A VIKING View Post
Thanks Integrity!
For cyclic I am running Savox SC1268SG which does state in the description they can be run with unregulated lipos.
For the tail I am running a Savox SB2272MG which is HV also but they do not have the same statement in the description about the use of a unregulated lipo.

I'll try to contact them and ask if it is ok for the tail servo to unregulated.
I am almost positive it will be ok and the first flight will be nothing but pitch pumps and pirouettes and then a check of the reported buss voltage from the SK.
The buss voltage from the CC Pro BEC never changed more than a tenth of a volt when being beaten, it worked well.

Thanks for all the great info, I appreciate it.
Yup, that is what a regulator does. As the current demands change, the regulator adjusts to keep the voltage from changing. It might change a few tenths of a volt, especially during hard peaking current spikes. But that is about all it will do. So you'll definitely see fluctuations, spikes, and general changes to the voltage with only a lipo. But for me, since the values don't reach critical levels and i can't feel the changes. I've been fine with it. I just make sure to use good condition RX packs and things should be safe enough. Checking the internal resistance and examining the wires for fraying, etc. isn't such a bad idea either.
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Old Aug 24, 2014, 01:09 PM
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Do any of you guys know what it takes to take the push button apart on a Spektrum TX?
I am trying to relocate the push button to another position on the TX that will be easier for me to use for the SL feature of the Skookum.
The tall chrome nut that secures it will easily unscrew almost to the end of the threaded portion of the switch and then abruptly stops.

Anyone know how it comes apart? I checked both my DX7 and DX9 and the switches are the same in that way, I just can't figure it out.
Looks like it should just unscrew but it won't unscrew all the way, I am missing something but don't know what it is.
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Old Aug 24, 2014, 01:19 PM
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I did setup a couple 600s using Castle BecPro on 3s for the guys in my flying group. Mostly due to the lower cost factor. Hundreds of flights so far and zero issues! And as you said Martin, very little voltage fluctuation. Most the hard work for a Bec is due to damping down high to low voltages! With 3s they barely have to work at all to regulate it down. As usual, heat is the enemy. I took this info into account when setting up my own. The only problem in over 2000 flights I have had is with my very old, and bought used Herc. One of the caps on the board had corrosion on one of its tabs and broke loose. Who knows how many wrecks that old bugger had seen? So I cleaned and soldered the tab, then also removed its small voltage adj switches, leaving it permanently at 8.4v. I doubt I will ever have an issue again with that one.

They all run quite cool. As do for the most part all my servos. Which is why I bought high end servos to start with. (in most cases used on the cheap).
I just rarely drive them as hard as they are designed for, as my style is more graceful, smooth transitions, none of the crack jack 3d stuff at all. Except a couple sets of tic tocs.

I don't believe I have ever even had them come down warm? The name of the game in large helis and flight is equipment consistency, you simply never want the servos slowing down when you need them the most. The logs in the Skookum will tell all when you go look after doing the 2s Rx pack! I bet you will be just fine.....
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Old Aug 24, 2014, 01:24 PM
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Quote:
Originally Posted by A VIKING View Post
Do any of you guys know what it takes to take the push button apart on a Spektrum TX?
I am trying to relocate the push button to another position on the TX that will be easier for me to use for the SL feature of the Skookum.
The tall chrome nut that secures it will easily unscrew almost to the end of the threaded portion of the switch and then abruptly stops.

Anyone know how it comes apart? I checked both my DX7 and DX9 and the switches are the same in that way, I just can't figure it out.
Looks like it should just unscrew but it won't unscrew all the way, I am missing something but don't know what it is.
Pretty sure they have a friction stop, just force them a little and the nut will come loose. I believe they do this as a safety measure. Take a very close look and you should see a slight nick in the threads.
I am looking to do the same mod with my Jeti after reading your posts over in the HF section about this. Pretty cool what the new software upgrade allows now! Self level bailout active in three banks or more. Plus, a delay! Allowing for positive pitch to be applied just as the BD does!
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Old Aug 24, 2014, 02:22 PM
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Originally Posted by Luvmyhelis View Post
Pretty sure they have a friction stop, just force them a little and the nut will come loose. I believe they do this as a safety measure. Take a very close look and you should see a slight nick in the threads.
I am looking to do the same mod with my Jeti after reading your posts over in the HF section about this. Pretty cool what the new software upgrade allows now! Self level bailout active in three banks or more. Plus, a delay! Allowing for positive pitch to be applied just as the BD does!

I did do exactly that early today on my DX9.
Now the nut just spins up to where the friction was felt before preventing its removal and now just spins freely in that spot without coming off.
The nut doesn't have any friction on it, it spins off freely on the threaded portion of the switch until it gets to the end and just stops.

Pretty exciting stuff with the SL setup, like I said over on HF, my 770 is going to hate me.
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Old Aug 24, 2014, 02:29 PM
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What is this? All in relation to the latest SK720 firmware?


I can't really say why you can't get that nut off the switch. What LMH said sounds logical. Worst case, you can pick up a push button switch at Radio Shack or something for about $3-5, i would imagine.

I really doubt i would ever use the bailout switch if i had one of those gyros. I can see where i might have its uses if you loose orientation or something. But they seem just unpredictable enough to scare me. My plane has a feature like this that will turn the plane upright and level it out. I honestly never think to use it. Plus that button is a little out of the way.
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Old Aug 24, 2014, 03:34 PM
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Quote:
Originally Posted by IntegrityHndywrk View Post
What is this? All in relation to the latest SK720 firmware?


I can't really say why you can't get that nut off the switch. What LMH said sounds logical. Worst case, you can pick up a push button switch at Radio Shack or something for about $3-5, i would imagine.

I really doubt i would ever use the bailout switch if i had one of those gyros. I can see where i might have its uses if you loose orientation or something. But they seem just unpredictable enough to scare me. My plane has a feature like this that will turn the plane upright and level it out. I honestly never think to use it. Plus that button is a little out of the way.

Trust me the switch removal is not logical. I have posted everywhere including Horizon techs to help me out with this one.

The SL thing is something that I didn't use a lot of because it was always interfering with my planned flight path.
Now with the latest firmware update we can put SL on the bind push button and with creative programing of the firmware and TX you can have SL available at anytime flying any bank in the Skookum.
It will no longer interfere with your flight path when you don't want it.

It does take some time to get used to. It's pretty scary on the 770 size machine to see it happen but its something you get used to with time.
I would put the 770 in an unusual attitude and hit SL just to see it happen so I knew what to expect.
This trains you for when the real deal is needed so you don't freak out watching SL fly the ship.
With the intermittent push button switch it becomes even more useful in that you can get yourself in a bad place and just tap the button once to right the ship and take control again.
Working SL with a switch or having it turn on with "center stick" is not useful for someone learning hard 3D, but the push button is perfect.

You would be surprised to see how fast the SL will right the 770 on its highest setting. It's just scary but accurate.
You can turn this setting down to allow a more gradual righting of the ship if you want.
If your close to the ground though you would want the highest setting to right the ship as tightly as possible in the smallest space.
Works good.
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Old Aug 24, 2014, 07:48 PM
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Xrayted over on HF figured it out for me so I was able to change the position of my push button for use with SL on my DX9.
See the photos for the new position of the switch.
I am a pincher so the bottom corner of the TX places the button in a perfect spot for quick actuation if needed.
Push the button, self level is on, release the button, self level is off.

Now I can enjoy both flight banks I set up in Skookum without interference from self level, but if I need it, it's a push of the button away.
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Old Aug 24, 2014, 08:32 PM
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Quote:
Originally Posted by IntegrityHndywrk View Post
Yeah, I've heard those BD gyros have a bad problem with brownouts. I'm pretty sure the BeastX, SK, Vbar, Ikon, MSH and other gyros aren't as sensitive far as i know.
The issue is only related to Spektrum Sats AFAIK. If you are using direct sats you MUST supply at least 5V to the BD unit (any less than that and you risk the sat shutting down). They recommend 5.5V minimum BEC setting.

Personally I would not use Sats on the BD unless running HV or a 2S lipo/life too risky. If you plug a separate RX in though you should be good down to the ~3.5V Spektrum rates its RXs.
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Old Aug 24, 2014, 08:57 PM
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So Martin, how finally did the switch nut come out? Just really curious. And was hoping someone would chime in about the BD brownout issue and clear it up. I heard talk it was the sat and not directly the BD. But either way. I would still run sats myself. I like clean simple wiring when possible.
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