Freewing Su-35 (Vendor-independent; please read 1st post and stay on-topic) - Page 399 - RC Groups
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Jan 14, 2013, 10:36 PM
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Originally Posted by PeterVRC
Yes, you surely can... and that will be fine.

I always add a "JST pigtail" to the battery connector (XT150) side when making up the main power leads. Thus a tap to get the battery voltage to a BEC etc.
This is so I can plug in a small battery instead (2S or 3S) to run all the electronics for testing, and not need put put in a flight battery.

Not a fantastic pic but you can make it out.....
WOW! thats some heavy duty looking conectors!. I baught every conector I could find this weel and NONE look like those. Where did yo buy that stuff?
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Jan 14, 2013, 10:46 PM
jcdfrd's Avatar
yep those are the xt150's I spoke about, you get them from HK
goldsworthy you can use your bec on a 6s batt but just know that you have a 5amp bec when you do that and also you need to get some airflow to the bec if your going to do it that way, it will run quite a bit hotter on 6s and needs cooling
Jan 15, 2013, 12:34 AM
Registered User
Is that a Linear BEC ?
Jan 15, 2013, 12:50 AM
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Maxthrottle's Avatar
Switching..... CC BECs are switching. But if you are thinking to pair two of them CC gives the following setup recommendations for multiple BECs.
Otherwise from Q&A
5. Can the CC BECs be run in parallel for very high current applications?
No, switching regulators like the CC BEC will fight each other if used in parallel. A separate component is needed to isolate them from each other. Castle is looking into creating something that will allow you to do this. Stay tuned!

They are looking at adding a isolator that you plug into. The two Turnigy Switch BECs that you're using Pete, do they have some kind of isolator?
Last edited by Maxthrottle; Jan 15, 2013 at 01:08 AM.
Jan 15, 2013, 12:58 AM
Should've, Would've, Could've
v8truckin's Avatar
Watch out Max! Pete's gonna catch up to you in posts.
Jan 15, 2013, 01:12 AM
You are a "go" for reentry
Maxthrottle's Avatar
Originally Posted by v8truckin
Watch out Max! Pete's gonna catch up to you in posts.
Oh no Save your selfs..... I never noticed. I'll stop posting so he can pass me and business as usual
My numbers of posts doesn't reflect on my intelligence or experience..... it just means I'm chatty
Jan 15, 2013, 01:22 AM
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My two BEC's run individual RXes, so there is no 'sharing' or connection of the two.
Of course all commoned (Gnd) but that is it.

I mentioned once before how easy it is to even run two BEC's on the one system... still totally isolating them from each other, by each powering X amount of electronics only.
No components needed at all, just plain wiring setup. Simple.
I can't see why there has been this big fuss over mutliple BECs ongoing, when it is no problem at all to set it up properly.
I guess i will have to make a Blog entry, to save ever typing it again....
Jan 15, 2013, 01:33 AM
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Maxthrottle's Avatar
Ooop yep that's right. So they are automatically isolated. I'm surprised more radio makers don't untilize this more instead of single high channel count RXs, have lower count RXs with assignable channels. Especially either mirrored and or high low criticality.
Do those RXs doing it by PPM connections or is it a different in house sharing and assignment of channels?
Jan 15, 2013, 05:13 AM
Registered User
ER9X - the replacement firmware for the T9X - has the coding to do 16 channels. That is simple software programming. But then of course you need to get them to a TX for transmission. That was easily accomplished because the T9X (and almost all computer radios) have a trainer port. This normally outputs a PPM stream, or accepts one in.... designed to go to, or from, another TX for training use....but that means you can easily use that port as an output port for the extra 8 channels then! Rather than the typical 'copy' of the standard 8 channels going out the trainer port.
Thus all you need to do is feed that PPM stream into another TX module - presto, two 8 channel systems, running from the one TX (T9X).... out to two RXes in the plane... to give you 16 channels in total.
All for under $200 really.....
Jan 15, 2013, 05:22 AM
Registered User
To run two BECs.....
You have to make a wiring loom that takes X amount of your servos Pos and Neg leads, to a pair of common 'rails' That is.... X amount of your servos plug into the RX as per usual, the rest (however many you wanted to split to another BEC) go via the loom.... it commons all the Gnds and all their Positives.
The signal wires still go to the RX as per usual.
The common Gnd still goes to the RX... just to one RX Gnd pin will do (or via all servo plugs as usual) - this is so the entire system still has a common ground.
The common Pos only goes to the 2nd SBEC.... thus all of those servos get their main Pos power from the 2nd BEC, but still get the signal to control them from the RX. The common Gnd ensures all signals still work correctly.

The best way to do this is make a loom as mentioned - by using Female servo sockets for the servos, just so you can plug things in 'normally' and replace servos etc.. Then use the 3-wire leads from those to common all the Pos and Negs.
Then use the same number of Male plugs to connect the signal from each servo to each of these plugs, with a Gnd from the common point. You do NOT connect any Pos leads to these male plugs!! Otherwise it would common the SBEC's again via the RX connection!

So in the end you will have X male plugs loomed to X female plugs (same X total), and a "tap" off that centre joint to get to the Common Neg and the isolated Common Pos of the SERVO side of them.
The 2nd SBEC feeds into this created Pos and Neg tap.

You can make this up quite cheaply using X amount of servo extension leads. Leave the SIGNAL leads intact - going right through. Trim the Pos and Negs to whatever point/lengths you want - you are basically going to be rejoining them via a 'connection hub' at some point between the total rejoined length.

Last edited by PeterVRC; Jan 15, 2013 at 06:00 AM.
Jan 15, 2013, 05:32 AM
Suspended Account
Are 8 channel recievers enough to run everything in a stock SU35?
Jan 15, 2013, 05:50 AM
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"Everything" within minor limitation.
You really need 9 channels to run "everything"... with 8 you need to pair the rudders to the TV yaw (rudder).

To set up all surfaces to do all possible actions, you need one channel per servo (eg no 'paired' ones like ailerons, or the rudders), plus the throttle, gear etc. About 12 channels.
Jan 15, 2013, 05:53 AM
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1) Aileron left
2) Elevator left
3) Throttles (both)
4) Rudder left
5) Gear
6) Aileron right
7) Elevator right
8) Rudder right
9) Nose wheel steering - so it can be controlled/trimmed independant of the rudder(s).
10) TV left
11) TV right
12) TV yaw
Jan 15, 2013, 05:55 AM
Registered User
For less channels....
1) Ailerons linked - no ability for flaperons or spoilerons then. (or mixed to elevators with full 'openess')
2) Rudders linked - no rudder airbrakes
3) No nosewheel independence
= 9 channels

4) Linked rudder to TV yaw
= 8 channels
Jan 15, 2013, 06:17 AM
Life begins at transition
Can be done 8, it's how mine was set up...

1 - Rudder (stock has it Y-d to NWS)
2 - Elevator (stock has both Y-d)
3 - Throttle (stock has both Y-d)
4 - Aileron (stock has both Y-d)
5 - Gear (stock has the sequencer to include doors)
6 - TV pitch L
7 - TV pitch R
8 - TV rudder

6,7 and 8 on a switch to enable/disable the mix.

Not ideal, but then you don't need a 9+ch Tx.

I do like my 16 channel, sub $200 radio

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