Used hc3sx issues?

[umox]

Hi guys I've just installed a used hc3sx into my goblin500, my 630 has a brand new demon 3sx and I love the flying characteristics so I decided to give a used one on eBay a shot.

Problem im having is while doing a maiden hover I got a sudden + pitch for a split second which caused the heli to shoot up slightly at first I thought it may of been caused by the wind and thought nothing of it.

On on the second flight with a new battery I did a few slight figure of eights and switched into idle up
while flying around as expected totally smooth no issues I came into hover about 8ft tail in directly in front of me the same thing happened again no input from me and as I was in idle up mode the jump with + pitch was even more noticeable and definately not caused by wind this time so I clearly have a problem.

Any ideas what could possibly be an issue would be great, was flying with mini vbar last summer with no issues at all the goblin is setup perfect on linkages and pitch angles.

is there anywhere I can send the unit to get the once over so to speak to give a clean bill of health?
Ive just received my new spirit so I'm going to install that in and pop the hc3sx into my 450 I don't mind that going in so to speak.

Servos are ds610 and using a castle 80 6s esc with built in bec not sure on voltage will check once I get home.

[gary911]

I have had the very same thing happen to me on my bavarian demon 3x which is essentially the same unit. I am using it on my big Scale vario jetranger. I contacted bavarian Demon directly as I could find no issue with my electronics.

They said that if you are using spektrum you can't just plug in 2 satellites into the unit but will need to run a receiver too.
I then asked why do they have 2 inputs on the flybarless unit which suggests you don't need a receiver. I am still waiting for a reply.

I have 3 Bavarian 3x units for my scale heli's and have now had to buy 3 Jr receivers I have not tried this out to see if this will eliminate the problem but will be trying this out soon when I finish my R22.

I have got the latest firmware so that is not the problem. I have found some other people in the USA on Scalehelis.com who are having this problem but as yet no answers. I am using DSM2.

I am baffled.

[Mark_T]

I'm not quite sure how it would be relevant here, but historically the problem with using satellites on the BD units has been voltage related.

The 3.3V output for directly connected satellites has an unusually high overhead which means you need to keep the voltage above 4V, whereas with a full receiver you can dip lower than that without problems.

I wouldn't have expected there to be an especially high load on the servos etc. while in the hover, but if any of you have any telemetry on the models it would ber interesting to see what the voltage was doing at the time you had the problems.

[umox]

I was running x2 dsm2 sats at the time on the 500, voltage did cross my mind but as I was using the same setup on the vbar without any issues I did not think anymore about it.

I could remove 1 of the sats and see if it sorts out that issue but I'd rather not take the risk.

Im going to swap the 3sx that's on the 500 with the spirit fbl and put the 3sx on the 450pro with 1 dsm2 sat and see if that sorts it out.

On my 630 I'm running x2 dsmx sats and tm1000 unit but I'm using a separate battery pack for electrics and so far I've not had any issues at all and enjoy flying it which is why I decided to have the same unit on the 500.

I will keep you updated with how the 450 gets on with the 3sx and 1 dsm2 sat.

Cheers for the feedback

[kev2009]

Hi guys, not sure if this will help you out, but running dsm2 sats has major issues with the hc3sx, for dms2you need Rx not sat only, for sat only on hc3sx, it needs to be DSMX and bind to 11ms in the radio, as your servos are running at about 8ms, plus with sat only if your voltage draw drops below 5.5 volts it will cause these issues, as with Rx it can drop to 3.3 volts,

Hope this helps kev, The same on a vortex when voltage is low it will let you now by doing a pitch up,

[Roger_Salmon]

Interesting. I have one unit on a Protos 500 with 2 satellites and never have a problem with it. My other unit will not work reliably with satellites even when I use it with a separate 6V power supply. This unit has to used with a receiver or I get all sorts of random glitches in flight.

[kev2009]

Interesting. I have one unit on a Protos 500 with 2 satellites and never have a problem with it. My other unit will not work reliably with satellites even when I use it with a separate 6V power supply. This unit has to used with a receiver or I get all sorts of random glitches in flight.

Have you checked your radio for 11ms, and when you configer hc you must bind DSMX on RC page, Kev

[Roger_Salmon]

Have you checked your radio for 11ms, and when you configer hc you must bind DSMX on RC page, Kev

The Protos uses DSMX satellites on 11ms but it also worked well on DSM2. It also runs on the BEC from a Koby 70 on 5.5V. The other unit was tried with every combination of satellite and 11 and 22ms but would always glitch in flight even on a 6V separate supply. Works fine with a receiver though.

[umox]

The problem with sats only is this an issue across the board so to speak or just with the helicommand and not the demon.

I know essentially they are both the same unit just wondering if there was any slight tweaks/changes made with the new brand.

[umox]

Well I checked the voltage of my cc bec that was powering the electrics and it was showing default 5.1v which is below the recommended 5.5v stated in the manual for dual sats.

Ive got 2 dsmx sats on the way and have changed the voltage to 6.5 will update once its all installed and tested.

[woodsta888]

I had DSM2 sats on my BD3SX in my 800 and had problems. I run a Life Battery to power all electronics with no BEC from Lipo. I had shutdowns/brownouts and very rarely twitches across the control surfaces. My sats were on opposite sides of the frames and may not have been far enough apart. I changed to full RX + 1sat and never had problems since.

Also installed the TM1000 telemetry which is relatively cheap and will monitor RX battery power as standard and signal strength between the TX & RX. Helpful to rule out brownout and will show you which orientation is weaker for signal. Measures every frame loss, holds and which RX is dropping frames. Easy to give yourself an alarm for lipo pack voltage too to maximise flight time (seperately purchased lead). General consensus is run a full RX with the BD3sx.

Stolen from the FAQ for the BD3SX on helifreak

5.So what is the story with Sats? Why so many threads about Sats?As near as I can tell there have been more threads and discussions about Sats than any other topic. As far as I know, Spektrum never intended their Sats to be used directly with third party FBL controllers. They were only intended to be used with Spektrum RX’s like the AR7610. So companies that make FBL controllers that support using Sats directly have had to reverse engineer the signal decoding. None of the FBL companies have licensed the Sat signal protocols from Spektrum. With the 3SX, there have been two Sat related issues: voltage requirement and binding mode.
6.So what is the voltage issue if I use Sats?The downloadable BD3SX instructions say if you use Sats you should have at least 5.5V on your control power. They also say 4S NiMh is not sufficient. So it seems reasonable to just set your BEC for 6V, use 5S NiMh, 2S LiFe, or 2S Lipo. Some people have posted that some BECs that are built in to ESC’s (internal BEC’s) do not supply enough current. If the control voltage gets pulled down too low when loaded, the Sats will “brown-out” i.e. lose connection with the TX. This is obviously something you don’t want to happen. Spektrum RX’s (even with Sats) are rated down to 3.6V and the BD3SX is rated down to 4V. So I think it’s fair to say that using a full RX buys you 1.5V of safety margin over using Sats. I’ll share with you that I have a Trex 550E running two Sats. My power system is a Castle BEC Pro along with a 5S NiMh buffer battery. I have never had a Sat brown-out.
7.So what is the binding mode issue if I use Sats?Spektrum has two binding protocols (DSMX and DSM2) and two frame-rates (11ms and 22ms). So there are four combinations. The mode and frame-rate are set at binding and you have to rebind if you want to change the mode or the frame-rate. At one point there was a firmware change log that you could view or download from the BD website (which I did) and you could tell there were issues with the binding mode in the past. In particular, DSMX at 22ms seemed to cause problems (sudden servo jumps). Supposedly, the binding issues were fixed in firmware updates but as far as I know, your best bet is to use DSMX at 11ms. So if you have an older TX that has DSMX but not 11ms frame-rate (like the DX7s), don’t use Sats. I am not really sure what to say about DSM2. Some guys have posted they use DSM2 and have not had problems.

[umox]

Just a quick update.

I've installed 2 dsmx sats at 11ms and upped the voltage on my cc bec to 6v

done 4 lipos today at the club. 2 packs hovering and 2 packs general circuits and everything seemed ok no glitches of any kind.

Did not try out rescue mode so can't comment if that will cause any issues as the manual States it's quite hard on the electrics.

will do a few more packs hopefully tomorrow if the weather hold and see if it continues to behave.