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Twin esc, one channel


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Can i just clarify please...

 

To run two motors / two ESCs /two batteries on one throttle channel- BOTH signal leads and BOTH negatives go to the rx, ONE +ve lead goes to the rx.

 

Crucially the +ve leads are not connected together. Only one of them feeds the receiver and servos the other is cut and insulated.

 

Is that correct?

 

David 

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Yes. I would suggest doing the cutting of one of the +ve in the y-lead so that your ESC is ok to be used on its own later if you want to.

 

It is possible to connect both ESCs for redundancy if you use diodes, but you need the right type. Someone posted it on a thread with 4 ESCs, possibly EDF? 

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Personally I would not cut leads.

Just lift the tab retaining one of the red wire crimp connections, pull the connector out, turn it back down the lead and tape into position.

That way the connection can easily be reinstated if required at a later date.

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Not really as no damage is done to the connector.

 

You can also use this sort of system to use both BEC's for different uses.

I use a similar system so that one of the BEC's powers the radio and servos in the plane, the other powers the electric retracts for instance.

 

The other thing I would recommend (although I am sure others prefer a different method) is to common your lipo packs before splitting to each BEC.

This will counter any differences in pack performance and therefore ensure a balanced supply to both the motor systems. It also means the packs don't have to work so hard.

 

I have used this system for some years (15 ish) with no issues

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No same Rx.

 

Connect everything as usual.

 

Remove the red wire from the retract receiver connection as you have done with the 2nd Esc red wire.

The 2nd Esc red wire can then be connected directly to the retract red wire - job done!

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1 hour ago, David perry 1 said:

Is there a benefit to using two throttle channels?

Depends on the model. A lot of waterplanes use 2 channels for the throttle to allow for differential steering mixed with the rudder to help manoeuvring on the water.

 

If you do this, check that the failsafe works correctly to close both throttle channels on loss of signal.

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Nick,

yes understood.  I really meant apart from diff thrust....in this case specifcially.  I cant see one hence my natural assumption that I'd use a Y lead.  I think one Y lead, one missing red wire connected to a red wire of the joined retracts.  i.e. each retract unit red wire pulled and joined together, then joined to an esc red wire.  The the rx gets one red from an esc, and each retract gets 5v from the same, spare, esc +ve wire.

 

Phew

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Only my opinion. As above and remove one ESC red connector from its plug and sleeve/heat shrink for later use.

Keep it simple and use a Y lead unless you have good reason to need differential thrust, but normally a rudder works just fine.

 

In my experience sperate throttle channels just causes more complex setting up with throttle hold, throttle cut and fail safe to get it all to work how you want it.

 

And lastly differential throttle in flight (as the model had no moving rudder) can produce some very un-scale like effects (not the model pictured below) like high degrees or yaw as the motors fight the vertical stabilizer/rudder.

 

This does have differential  throttle option on a switch and does some very extreme "dinner plating" at the top of a vertical climb....but then again it does recover within 20 to 30 feet!

 

PS - Unless you make it bullet proof there is always a possibility that you leave differential switched in and do something with the sticks and get a very unwelcomed response. ?

 

PPS, What's it for?   

 

image.thumb.png.a9488ffe002a00853ca34e66ec553873.png

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I totally agree with Chris.

 

You do not need differential thrust for your Ju88 so keep it simple with both motor channels coming off a single receiver output with a Y lead.

 

I have a Twin Otter with switchable differential throttles for when it is water borne on floats.

Flying with differential throttle in normal flight is dis-concerting to say the least.

 

However it does do unreal stall turns with it switched in - a decidedly non scale manoeuvrer and would have all the passengers reaching for their sick bags I am sure.

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I think that on some Tx's the trim function doesn't operate on the slave output of a mix. Certainly was the case with some old Futaba outfits.

 

@Andy Gates A really neat, true scale, manoeuvre for your Twin Otter float plane would be the ability to reverse into position whilst taxying on the water. ?  

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Spent a couple of hours at Vancouver Harbour 22 years ago watching the comings & goings of the DH Beavers, Otters & Twin Otters. Fascinating to watch the Twin Otters use reverse pitch as brakes after touch down & also using it during taxying.

 

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A day or two later I had a flight in one of the Beavers doing commuters taxi service & postal run around some of the gulf islands.

Edited by PatMc
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Nice PatMc.

 

I never got to go to the west side of Canada, only Ontario which was good enough as a youngster.

Flew out and back on Freddie Lakers Skytrain - that shows my age a bit!

 

My Twotter stops quick enough without reverse thrust so no need - still a nice thought though?

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  • 1 month later...

Grrr Like an eejit I am.

I bought two 80a esc for my Ju88, all well and good.  Ive just come to wire them in and find...no BEC so no servo lead so no throttle control!!  I have bought the wrong type, but I dont think I have ever seen ESCs with nor control wire before.  What are these for and can I use them?  I think the answer to that is "no" but worth asking before I buy new ones WITH a BEC!!

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9 minutes ago, David perry 1 said:

Grrr Like an eejit I am.

I bought two 80a esc for my Ju88, all well and good.  Ive just come to wire them in and find...no BEC so no servo lead so no throttle control!!  I have bought the wrong type, but I dont think I have ever seen ESCs with nor control wire before.  What are these for and can I use them?  I think the answer to that is "no" but worth asking before I buy new ones WITH a BEC!!

 

Whether an ESC has a BEC or not (those without are generally denoted as "Opto", not honsetly sure why) there should still be a control wire with a plug on the end you can connect to your receiver. If there weren't how the heck would you control it?!

 

Post a photo and/or the make and model of the ESC and we can better assist; until that point I suspect we will remain pretty stumped tbh...

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