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How To Buddy Box?

#1
Hey folks...just joined. so...Hi.

For as much as I see the Josh's buddy box...it looks like a great idea to fly with friends! But the first time I tried it...it was not with such great success. I tried to use a DX6i as a master and a DX5e as a slave. I was surprised to see that when I flip the trainer switch, the DX6i settings go away and the DX5e settings take over. I was expecting that when I flip the switch, just the stick inputs are used on the DX5e but that the DX6i programming stays in effect since it is doing the transmitting anyway...that did not happen.

So do I really have to make sure that my DX5e has matching trim settings before I take off? That seems bad because if I do the take off and fly out on the DX6i, then trim out a plane...when I flip the switch, I could be giving the rookie a wildly out of trim plane to try and wrestle with even if its flying hands off for me.

I have noticed that the Josh's seem to have matching DX8's when they buddy box...is that because of the SD card transfer makes matching the transmitters easier? But then there is still the trim issue. I don't really have the budget for that anyway.

I think I saw somewhere that the DX7s & DX8 have more buddy box options like selecting which inputs will be buddied? Do I just need a upgraded master to do more buddying? I would love to do a buddy box for a 450 heli...but not if I have to buy two dx6i's and then make sure that they both fly exactly the same before flipping the trainer switch.

Adding a DX7s to the collection and retiring the DX6i or one of the DX5e's as a slave is the preferred option...if it would work better
 

Ak Flyer

Fly the wings off
Mentor
#2
I have a DX8 and DX5 and I've buddy boxed with those and a DX6i. The DX8 definitely makes it easier to setup because you can give complete control or just of the channels you want them to try. With my daughter I may give her elevator and aileron but I keep rudder and throttle. With the DX5 it's difficult because you don't have any expos and the dual rates are fixed. Those settings will not transfer through to the DX5.

Master controller has all the settings but once you flip over the slave controller has complete control, unless you set it up not to.

It is CRITICAL to ensure that your control directions are the same. You can check that on the ground. You can also set up throws if you have them tuned in your master radio.

You CAN get the trim pretty close on the ground. Fly and trim your plane with the master controller. Then with both hooked together you can look at each control surface and see where it sits. Then switch to the slave transmitter and adjust the trim so that the control surface is in the same position. That will get you close. If you have two computer radios (DX6i and up) then you can just copy the settings but ALWAYS VERIFY on the ground before flight.

It's really best to have two good pilots take the planes up and trim it with both controllers. You can do it with one by trading transmitters with your student and having him hold the trainer switch while you trim the slave controller.

Word of warning, check EVERYTHING. I failed to setup the throttle on my friends DX6i before he buddy boxed my nitro cub. He mad a slow pass and idled all the way down. I failed to set the minimum throttle position so it killed the engine and I had to take over at low speed, low altitude and over the brush. It made for a very exciting landing. Minimal damage.
 

pgerts

Old age member
Mentor
#4
I will always flip the trainer switch on the ground to make sure all trims and directions are the same om both tx:s before starting a training session.

Om some more advanced system there are several "trainer" modes as you describe.
 
#5
Also tell each other before switching how much throttle they are using. For instance if your buddy is flying 10 percent throttle and you have your throttle stick on 80% thats bad when you switch. Your motor will get try to speed up in a really short time which is bad for your engine.
 

Ak Flyer

Fly the wings off
Mentor
#7
You need to buddy box brand to brand. Spektrum to spektrum, Futaba to Futaba etc. I don't know of any exceptions. You may be able to backyard engineer a way around it but with computer radios, they need to be able to speak the same language. Best to stick to the same brands.
 

pgerts

Old age member
Mentor
#8
... Best to stick to the same brands.
There are ways to mix differnet "brands" - and they speak the same language on the tranier port (ppm).
The difference is :
- Connectors - you will find drawings on the net to make cables.
- Order of channels used. There are 2 main orders :
-- Futaba and Hitec and some others (throttle on ch 3)
-- JR Spektrum and.. (Throttle on ch1)
If you are an expert you might be able to try different "modes" to get it right but it is best to mix the buddy within them using the same channel orders.

(Some transmitters are freely programmable to select any channel to any stick).
 

Ak Flyer

Fly the wings off
Mentor
#9
Chances are, if you are in the buddy box stage of learning to fly, this all may be a bit much. If you have a simple model you could make it work I suppose but if you have any mixing or anything, that will get lost. Any unique programming would be difficult to ensure it's the same. Not saying it can't be done but I wouldn't recommend it.
 
#10
You need to buddy box brand to brand. Spektrum to spektrum, Futaba to Futaba etc. I don't know of any exceptions. You may be able to backyard engineer a way around it but with computer radios, they need to be able to speak the same language. Best to stick to the same brands.
there are ways to buddy box with different manufacturers hardwar, but it requires 2 seperate recievers in the aircraft, along with a possible reciever battery for the second reciever. i have not tried this myself, so im unsure if the reciever battery is necessary or not.

that said, hobbyking does sell 2 seperate buddybox systems, one for 4 channels and one for 8.
4 channel
8 channel

the 8 channel is technically only 7 channel with the 8th being the switch on the master to switch between trainer reciever and master reciever. i assume the same with the 4 channel model but it doesnt show a wireing diagram in the product photos like it does on the 8 channel model. as they state in the descriptions, this can be especially useful for fpv flying, even with uhf recievers like ezuhf, etc. that way your spotter can take over control at the flip of a switch if you say you are having trouble.

edit: looking at te products a little closer, it seems that a reciever battery is plugged into the buddy box system itself. but it may not be necessary with electric escs with built in becs. you could also wire in a seperate bec in line with the esc just as an added precaution, such as hk's mega bec 8 amp.
 
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lobstermash

Propaganda machine
Mentor
#11
I've had one of these 4 channel buddyboxes for a while, but had only tested it on the bench until today. Firstly, they take up a lot of space when you add the cables, but I managed to squeeze it into an AXN with two 6 channel receivers. I made it activate on the gear switch. I have to say, I was very impressed at how quickly it switched over. It was very handy with a pilot and plane maiden and saved the plane on many occasions.

I don't think you'd fit it on a heli, but for a fixed wing trainer with a reasonable sized canopy, it's brilliant.
 
#12
I've had one of these 4 channel buddyboxes for a while, but had only tested it on the bench until today. Firstly, they take up a lot of space when you add the cables, but I managed to squeeze it into an AXN with two 6 channel receivers. I made it activate on the gear switch. I have to say, I was very impressed at how quickly it switched over. It was very handy with a pilot and plane maiden and saved the plane on many occasions.

I don't think you'd fit it on a heli, but for a fixed wing trainer with a reasonable sized canopy, it's brilliant.
you could probably fit it into a 450 sized heli or larger that isnt flybarless as the flybarless electronics usually take up extra space unless it is built into the rx like the spectrum beastx reciever. not to mention you would have to set up each flybarless reciever to the exact same settings before you even tried to fly it on the buddy box system. if you are on a larger heli, you might get away with using the system with flybarless if the flybarless unit is seperate from the rx so that you only have to set up the flybarless once. however tail gyro gain in the computer would be a pita to get it to match across brands would be my guess.