Help! Why do I need 7 channels if I want flaps?

[Douglas]

I am flying my first plane, a Carbon Cub S+. I purchased a Spektrum 6e transmitter, which only has six channels, and the manual says you need a 7-channel transmitter to get the optional flaps. I didn’t know about the value of flaps at the time (I would like to be able to do shorter landings).

Forgive the newbie question, but why do I need seven channels for flaps? Elevator, rudder, ailerons, throttle...that’s only four of my six channels, right? I look at my receiver and I’m looking at empty slots.

Do other planes requires 7-channels if you want flaps, or is it just the Carbon Cub S+?

 

[Aireal Anarchist]

your correct ......you can program your transmitter to activate flaps thru one of your unused channels and unused toggle switches....pick an open channel in your reciever plug your flaps servo wire to that channel and then program a toggle switch to the either ch 5 or 6 which ever channel you chose to use for flaps

 

[FL_Engineer]

I believe Spektrum uses additional channels for SAFE and possibly AS3X. I have a buddy that ran into that same problem with the same plane TX. He ended up returning it and bought a DX8. I'm sure someone else that runs Spektrum knows more than me.

 

[Douglas]

your correct ......you can program your transmitter to activate flaps thru one of your unused channels and unused toggle switches....pick an open channel in your reciever plug your flaps servo wire to that channel and then program a toggle switch to the either ch 5 or 6 which ever channel you chose to use for flaps

Thanks, but all the YouTube videos I’ve watched about this plane say that you can’t have flaps without a 7-channel receiver. I don’t get why they would say that for this plane if it weren’t so. They would sell more optional flaps if you could do it with a six-channel, woudln’t they?

 

[JasonK]

it could be this ->
elevator, rudder, left aileron, right aileron, throttle, SAFE mode select, flaps (which is 7 total) - this is just an example, but it depends on how the club is wired up and if any channels are being consumed for non-control surfaces

 

[Douglas]

I believe Spektrum uses additional channels for SAFE and possibly AS3X. I have a buddy that ran into that same problem with the same plane TX. He ended up returning it and bought a DX8. I'm sure someone else that runs Spektrum knows more than me.

If this is correct, can i disconnect the SAFE and then use flaps? If I understand it correctly, the SAFE is just the GPS thing that recovers the plane and does auto-landings for you. i used it at first, but everyone has told me to turn it off so I turned it off and I no longer use it. If anyone knows the answer, please pipe in!

 

[Aireal Anarchist]

yes JasonK is right if it has those channels used for flight controller or programed for? you would need additional channels

 

[FL_Engineer]

I forgot about the GPS on that model, that may have been the issue... I would think you could get it to work if you disconnected the GPS and used that channel but that's only a guess as I've got no specific experience with this setup.

 

[Draftman1]

It was usually 4-7-9 channel radios made, it helped save manufacturing, no reason for a company to build a 5-6-8 channel, it would be too many products. Buy a 7 once and that’s all you will ever need

 

[Bricks]

It was usually 4-7-9 channel radios made, it helped save manufacturing, no reason for a company to build a 5-6-8 channel, it would be too many products. Buy a 7 once and that’s all you will ever need

^^^^ This is not even true saying a 9 channel would be much closer for all you will ever need. 7 will never cut it if you get nto 4 servos per wing 2 for ailerons 2 for flaps,( for crow or air brakes ) rudder, elevator, throttle. then add in retracts and open a hatch to drop something, anything else that might need an open channel.

 

[PsyBorg]

hrmmm. the dream plane...

4 channels for control surfaces.
1 throttle hold / lock
1 for dual rates / flight mode
1 retracts
1 for flaps
1 head lights on scale plane
1 running lights
1 for Bomb bay doors / sweep wing
1 for bomb drop / missile launch /ejector seat
1 tail hook or chaff
1 for video switching.
1 for sound toggle
1 for sound files.

Yup seven channels not gonna help here hehe

 

[Indy durtdigger]

If you mean a DX6e when you say 6e then your radio has 7 programmable toggle switches on it not counting the gimbles for your flight control surfaces. Since you don't need one for landing gear that TX should be able to handle adding flaps to one of them, it should be able to handle it even if the plane had landing gear.

 

[JasonK]

If you mean a DX6e when you say 6e then your radio has 7 programmable toggle switches on it not counting the gimbles for your flight control surfaces. Since you don't need one for landing gear that TX should be able to handle adding flaps to one of them, it should be able to handle it even if the plane had landing gear.

We looked up the plane in question and the receiver/flight controller appears to consume 2 channels for flight mode + GPS auto pilot inputs. So 4 channels for flight controls + 2 for the flight controller -> all 6 channels for the dx6e.

 

[Indy durtdigger]

We looked up the plane in question and the receiver/flight controller appears to consume 2 channels for flight mode + GPS auto pilot inputs. So 4 channels for flight controls + 2 for the flight controller -> all 6 channels for the dx6e.

He said he isn't using the GPS anymore so he has free channels. Here is a thread from earlier this year on the same question. https://forum.flitetest.com/index.php?threads/flaps-on-carbon-cub-s.61801/
It isn't ideal by any stretch of the means but it can be done. If returning the DX6e and getting a DX8 of some sort is an option that'd be the way to go.

 

[sprzout]

In order to fly the Carbon Cub S+ with only 6 channels, you will need to remove the SPMA3232 flight controller and the SPM4647 satellite receiver, and replace it with a non-flight controller receiver. This will remove stabilization with the plane, so you will need to adjust more often, as well as removing GPS functionality.

The DXe transmitters that come with the ready-to-fly version will support up to 9 channels, per Spektrum's website, so if you wish to use the system as is without replacing the receiver and flight controller, you will need a transmitter capable of supporting 7+ channels:

1 - Throttle
2- Rudder
3 - Left Aileron
4 - Right Aileron
5 - Elevator
6 - Flaps
7 - SAFE

Removing the flight controller and satellite receiver, and replacing it with a 6 channel, will bring you down to 6 channels, minimum, as the SAFE is built into the flight controller. Theoretically, you could get it down to 5 by putting the left and right ailerons on a Y, but I would NOT recommend that - power gets a little funky and you could have potential issues with servos not working or dropping out due to the battery elimination circuit amperage, which could result in a crash.

That is the only way to do a 6 channel - replace the receiver and flight controller.

 

[sprzout]

He said he isn't using the GPS anymore so he has free channels. Here is a thread from earlier this year on the same question. https://forum.flitetest.com/index.php?threads/flaps-on-carbon-cub-s.61801/
It isn't ideal by any stretch of the means but it can be done. If returning the DX6e and getting a DX8 of some sort is an option that'd be the way to go.

Agreed on this - an 8 channel transmitter will give a LOT more flexibility in other planes - especially if you get in to flying planes with retractable landing gear, or a bomb drop, in addition to the flaps.

The DX6e is just limited to those 6 channels. It works great for most planes, but you'll find you're bumping up against its limitations fairly quickly if you want to get into some more exotic planes. 8 channels is pretty much that sweet spot.

 

[moret]

Theoretically, you could get it down to 5 by putting the left and right ailerons on a Y,

I have that plane. The left / right ailerons are already on a "Y. I know this because out of the box my ailerons would not work and as a very new plane owner, it took me awhile to find the problem. The factory had plugged the "Y" cable in backwards. I have removed the GPS unit so autoland etc does not work but still have SAFE on a switch. I use the plane now to let people who never have flown, fly it