Conference vmszoo::rc

    
>    1)	When using a trainer cord, should the instructor radio and the
>    student radio both have transmitter modules in them?  If only one
>    has it, which one?  If both have to have transmitter modules, I
>    assume they should both be on the same channel?
    
    I have a 7-FGK and the owner's manual doesn't say anything about
    the transmitter module.  You might not need it on one of the
    transmitters.  One transmitter is left OFF, the other is ON and
    does ALL of the transmitting.
    
>    2)	How do the switches get set when the student is in control,
>    and how are they set when the  instructor is in control?  Since
>    there are 4 combinations of 'trainer' switch, what does each
>    combination do?
    
    The manual says that either transmitter (the ON or OFF one) can
    be the instructor's box.  The instructor pulls (and holds) the
    trainer switch while the student is flying and lets go of the trainer
    switch to take over.  I have no idea what happens if the trainer
    switch on both boxes is pulled, but I wouldn't try it first during
    a low high-speed pass!  (or in your case while pushing sand over
    a 20' cliff).

>    3)	What codes actually get sent between the 2 boxes over the cable?
>    If I were to make my own encoder, could I interface it to the box
>    via the trainer connector, and if so, HOW?
    
    Just a guess, but I think it's the encoded pulse stream.  I say
    that because it's only a 5-pin connector.  I think the slave box
    gets power to the encoder circuit from the master but no power to the
    RF section.  I hope someone will correct me if I'm wrong.  If this
    is correct you could just generate the encoded pulse stream yourself,
    buzz out the connector with a scope to get the proper pinout, and
    change the trainer switch from momentary to on/off.

>    I'm not sure I _need_ a trainer cord for a land vehicle, but it's
>    not _too_ many dollars, and it might give me an easier computer
>    interface than chopping up one of the control boxes or hacking up
>    an interface for the transmitter module....
    
    If you want it for interfacing, don't bother buying the cord.  It's
    a standard 5 pin din connector.  You can get one at Radio Shack
    for $1.59 (I had one in the drawer for my son's computer and just
    tried it, fits perfect).  It's catalog #274-003 if you're interested.

>    Many thanks for any hints!
    
    No problem, or how's it go, pornada amigo?  Wish you had made it
    yesterday - I was looking forward to seeing the creature (the earthmover,
    not you!).
    
    Bill

    
    Not as important with a land vehicle, but I should add that you
    have to match the trim settings so neutral is the same on both
    transmitters.
    
    Bill
    

    You not only have to match trim settings (on the ground) but servo
    reversing as well.  The student doesn't want to have up and down
    reversed to confuse him.  I think that trainer cords and buddie
    boxes are unnecessary if you have a good instructor.  The other
    problem is that you need your instructor to have a compatable radio
    to use your trainer cord.  He then has to be willing to mess up
    all of his pot settings and trim settings to match your plane. (also
    the reversing switches)  The student also doesn't have any feedback
    as to what the instructor does with his Master when he takes over
    to save the plane.  I think that it is better if the instructor
    can talk the student out of a jam and grab the box as a last resort.
    I realize that this could result in a crash if a screw up happens
    at the wrong time, but very inexperienced students should be flying
    several mistakes high until the instructor knows how they react
    to verbal commands during a mistake.  I'm sure that there are others
    that will disagree with me on the buddy box usefulness.
    
    Charlie
    

I have to agree with Charlie in his last RE.  A good patient instructor, in 
conjunction with a good trainer(aircraft) [in my opinion] beats the buddy box 
hands down, and I really can't imagine why one would need one for a ground 
vehicle.... are fatal crashes a problem on the ground????   I've seen 
virtually as many, or more crashes _with_ the buddy box set up as without.  
These result from inadequate experience with the system, switched reversed, 
cords unplugged, etc.  I also think ones learning curve in nowhere near as 
steep because the student prolongs the inevitable near miss!  

Each to his own!

-Brian

    Wow!  Thanks much for all the feedback!  I don't really need the
    cord for training (though it might be nice), I'd mostly like to
    be able to keep out of the box and just feed it the encoded pulse
    stream instead of tearing it apart to splice in my A/D and D/A
    converters.   Not too many crashes, but I did manage to roll the
    Tyke the other day, sure did look strange with the horizon rolling
    around like that on my TV!
    
    Willie

Last night I spent some time with my flying buddy trying to figure out how
the training cord works on the JR radios. We want to try this because my
friend has spent three years trying to hover a helicopter without much luck.
He has pronounced that this will be the last summer of trying. Unfortunately,
I have a JR Century VII, and he's got a JR Unlimited series and a Circus
el cheapo. 

What we found is this. All three radios have a DSC output jack. With the
transmitter switched off, plugging something in the jack enables the 
encoder output and you get your pulse stream coming down the cable. Turning the
transmitter on, disables the pulse stream coming down the cable. At least it
does on the Century VII and the Circus radio. I don't remember on the Unlimited.

The Century VII and the Circus radio both have trainer switches on them. What we
found was that if you plug one end of a cable into the DSC jack on a transmitter
that is switched off, and then plug the other end into a transmitter that is 
turned on, the training switch on the transmitting unit then selects between 
the pulse stream coming in thru the DSC jack or the unit's own encoder.

It works. Its cheap. We can slave the Unlimited series radio to either of the 
transmitters with a training switch. The rub is that I would rather the
'on' transmitter be the student's unit instead of the instructor unit. I could
teach my friend to fly using my helicopter I suppose but the whole point of
this was to get him use to hovering his helicopter with his radio. We did 
investigate another option, both the Century VII and the Unlimited have plug
in transmitter modules. We tried swapping the modules which worked ok. I have
reservations about doing that though. Both our radios have been working just
fine. I'm a little worried that if we swap modules long enough eventually 
we'll induce some connection problems.

If anybody has some additional insite into how the JR training cord works, I'd
appreciate hearing it. I think we have it figured out but maybe there's a curve
in there somewhere that would let me run it the way I'd like too.

Dan Eaton

    Dan,
    
    I can't speak secifically to JR but, to my immediate knowledge,
    what you've discovered is universal to trainer-cord setups; the
    student Tx is always off (antenna collapsed) and feeds stick inputs
    to the encoder section of the [operating] instructor TX which, in turn, 
    radiates the signal. 
    
    I guess I don't quite understand the problem; why can't your friend's
    Tx be the instructor and yours the student?  Any slight differences
    between the two Tx's should be easily overcome once yer' buddy's
    learned the basics.  Or have I missed something??

      |
      | |      00	 Adios,      Al
    |_|_|      ( >o
      |    Z__(O_\_	(The Desert Rat)

    Al,
    the problem is we're talking helicopter radios. The more sophisticated
    the radio, the easier it is to fly the beast IF things are set up
    right. My friend's Unlimited series radio is a much better choice
    to fly with than the Circus el cheapo. But the Unlimited doesn't
    have the training switch. That means it has to be used as the student
    Tx. That's ok since that's the rig I want him to use. However, that
    means since I'm the instructor rig we and doing the transmitting,
    we have to pull the reciever out of my chopper to put in his. I'm
    not a big fan of moving working equipment around.
    
    Another option would be to use the Circus radio as the instructor
    rig since it has a training switch. That's probably what we'll end
    up doing. The only problem with that is I may really have to be
    on my toes if I need to take over since the Circus radio doesn't
    have all the built in capabilities the others do.
    
    What I would really prefer is a setup where the student rig transmits
    just like normal. When hooked up to an instructor rig, the training
    switch on the instructor's rig would control whether the student's
    transmitter took it's input from the student's encoder or the
    instructor's encoder.  Understandably, this set up require a bit
    more sophistication. Guess I can't have everything.
    
    Dan Eaton

    Well, if you have plugin transmitter odules, you shouldn't have
    any problems, and unless the connectors are really incredibly cheap,
    I would thing that they might even enjoy the occasional unplug/plug
    cycle, to keep corrosion at bay.
    
    Willie

  when in comes to just learning how to fly,i think the student(planes)
    learns more with out a buddy box,
     but when its time to learn to land they really come in handy
    i taught a guy to land a few weeks ago and saved his airplane
    more than a few times,the buddy box gave him much more
    confidence.
     he has a futaba set and takes the battery out of the student
    box,and removes the antenna,that way no one gets shot down
     

    	I have a futaba 6 channel set it has the place for the trainer to
    plug into. I was wondering if anybody has one they would like to sell.
    I am still learning how to fly. I haven't landed yet. but my plane is
    still in good shape never crashed. I have some good trainners. So if
    anybody has one please send me mail. 
    
    
    Thanks
    Mike        Krappa::rowley

    Has anyone ever used a Futaba AM radio as a slave to a Futaba FM
    radio with a buddy cord??  Again, Futaba sells 2 different buddy
    cords, but are they really different??
    
    Are the connectors the same??  Are the pinouts the same??
    
    I am willing to make mods to a trainer cord to make this work...
    
    thanks,
    jeff
    

Hey - that reminds me.  I have a Futaba FM trainer cord.  But I no
longer have any radios that it fits.  Anybody want to make
me an offer for it?  Gallon of fuel?

Bye          --+--
Kay R. Fisher  |
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