Ok - Some fun stuff to sort out here.
It appears you would like a stabilized system. So right off the bat, you do not combine multiple stabilized units inside a single airframe. So if you want to run an RB25S for example, you do not combine that with a stabilized receiver like the TD-SR6.
What RF system would you prefer the TD or the TW? For the a large plane like this, might as well run the TD, but either is a good option. I personally like the TD as you have 2 different frequencies.
If you would like a built in vario, then you will want to use one of the glider receiver, they will have a "G" in the name. But you can also simply plug in a vario sensor into any of the other receivers:
The FrSky VARI-ADV High Precision Variometer measures the rate of change of altitude by detecting the change in air pressure (static pressure) as the altitude changes. When used with the FrSky transmitter you can create a true glider vario with tones that indicate lift and sink. What's new is...
alofthobbies.com
For the question of dual receivers, this is never a bad idea, especially if you are worried about getting good line of sight from your antennas around a high carbon glider fuselage, or a tight radio compartment with lots of battery shoved into it.
The use of the RB systems could be a benefit for this model. It is not required, but as you push into bigger and bigger models the Redundancy Bus adds a number of very helpful safety features to the model. Think of it as an insurance policy, it can guard against a full system shutdown should a servo fail in a very bad way, etc.
So a possible build out might look like this:
RB25S:
The RB-25/RB-25S builds on the success of the previous trusted Redundancy Bus Series by adding new advanced features combined with a compact new design which meets the needs of users who want a flight-safe system built in a smaller size unit. Triple Receiver Redundancy & Dual Power...
alofthobbies.com
A pair of TD-MX:
The Tandem dual-band receivers are unlike any other FrSky 2.4Ghz or 900Mhz receivers, they work simultaneously at both 900Mhz and 2.4Ghz frequencies. That means Tandem receivers provide not only the low latency signal and long range control, also benefits from enhanced level of high reliability...
alofthobbies.com
Vario:
The FrSky VARI-ADV High Precision Variometer measures the rate of change of altitude by detecting the change in air pressure (static pressure) as the altitude changes. When used with the FrSky transmitter you can create a true glider vario with tones that indicate lift and sink. What's new is...
alofthobbies.com
Optionally add one of the power switches:
This switch uses a 3.5mm audio jack to turn on or off your FrSky Devices. Works with Archer plus/ Tandem/ Twin Receiver with 12 or more channels.
alofthobbies.com
That would be a pretty good system that will give you the vario, stabilization, dual receivers on dual bands, and the RB for power distribution and security.
Hope this helps. If you buy from us, I think it will need a custom harness to plug the vario into the first MX receiver, we can do that for you. Just add a note to the order.
