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Multicon Amp. compatable w/modern radio?

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Old 02-10-2003, 08:39 AM
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Default Multicon Amp. compatable w/modern radio?

Hi all...I've got a set of the old Kraft multicon retracts that have very little time on them...I'd like to get some use out of them, and am wondering if I change the connector, can I use them w/ my Hitec Flash 5 system? Thanks...
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Old 02-15-2003, 03:24 PM
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Default Multicon Amp. compatable w/modern radio?

Proptop--

Check out the thread: "Help Needed - Kraft Multicons" at the link below.

http://www.rcuniverse.com/showthread...Kraft+Multicon

I asked the same question and got some good replies.

I don't know what a Hitech Flash 5 system is, but it looks like unless it's a 4-wire servo system, what we've got are some nice paperweights.

Personally, I can't see where it would be a good idea to go into your flight pack and tap off half the cells as one suggestion states. I believe this would make the packs cells discharge unequally - can't be a good idea..
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Old 02-15-2003, 05:12 PM
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Default Multicon Amp. compatable w/modern radio?

Tapping the batteries at the half point dosen't make a problem since 1/2 of pack is used to raise the gear and the other half to lower the gear should work out OK.All the servos in the old four wire systems worked this way Can't recall ever seeing a problem with half the pack being lower.If you give up elevator one half the pack gets used and when you release and go to neutral the other half gets used. Equal or so close it can't matter.
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Old 02-15-2003, 08:20 PM
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Default Multicon Amp. compatable w/modern radio?

Oh, I see Albert. That makes sense. I thought you were saying you'd only use 2 of the cells all the time for the retract units. I was assuming the amplifier would determine the direction of the current for "up" or "down" but the 2.4v would always be drawn from the same 2 cells.

I was wondering if it might be possible to somehow divide up the wires to the 4-wire plug. Use a 3-wire plug on the wires that would connect to the receiver to control the signal to the amplifier, then use another plug to a separate 2-cell pack just for the power to operate the retract units. But it seems at least one (or more) of the wires would still have to be "shared" with both the 2-cell pack and the receiver plug. Any thoughts on this?

Of course, the instructions also show you how to use the Multicons on a 4-channel radio system where you use a switch controlled by the throttle servo pushrod (for when you don't have a 5th channel to plug into for "retract" function). I'm not crazy about this system as it's really mechanical/electrical and relies on the high and low throttle trim to retract or extend the gear. Maybe it would be OK once you get the stops for the switch positioned just right. Just seems kinda awkward to me. But, hey - you gotta do what you gotta do. I suppose if you have a 5th channel, you could use a small servo to actuate the switch but it's still a mechanical/electrical proposition and this also adds more weight (another servo). Being able to just plug the system into your receiver and use the existing flight pack is a whole lot less complicated! I do think I'd probably go with a flight pack with a little more capacity than say a 550 or 600 mah pack, though, to allow for the additional power draw.

So, Proptop, you CAN use the older version of the Multicons with any radio - it's just a little more complicated if you want to use them with a modern 3-wire system, and you won't be able to hook them directly into the receiver by simply splicing on a 3-wire plug. Do you have a set of instructions for you Multicon set? It shows how to hook them up using the switch controlled by the throttle linkage. If you need a set, I could copy them for you. Let me know.

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Old 02-16-2003, 02:27 PM
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Default Multicon Amp. compatable w/modern radio?

Another pack would work OK .Cut the Kraft connector off the amplifier attach the connector to match your present radio on instead.You will need only the black and orange wire from the amplifier.That is black is ground and orange is signal.Now you will have to splice a black wire,a red wire and a white wire from the amplifier to your second battery pack.The pack is four cells in series and the black goes to the negative end,the white wire is two cells up,2.4volts,the red wire is the postive end 4.8volts.You could get a double pole switch from radio shack and put that in the white and red wires and a charging jack to match your setup.Put the charge jack on the battery side of the switch on the red and black wires.
If you want to use one pack just cut the connector off and reattach the connector to match your radio wireing.That is red to red, black to black,orange to the color on your radio connector which is the signal line.Then connect white wire from the amplifier to a Radio Shack switch and then to your battery pack at the midway point two cells up from the black wire.which is the 2.4 volt point. Thats it .
Don't try to make this complicated.Think of the Kraft amplifier as a servo,Which it probably is,It just needs two voltages to operate properly a +2.4 volts and +4.8 volts.
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Old 02-16-2003, 08:21 PM
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Default Multicon Amp. compatable w/modern radio?

Hi guys, thanks a lot! I have the newer 3 wire amp. so I guess I can assume that I can just change the conn. and things will work ok?! At least that's what I gathered from the info...I'm good mechanically, but don't know a lot about electronics...Thanks again, Tom.
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Old 02-16-2003, 10:57 PM
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Default Multicon Amp. compatable w/modern radio?

That's good news. It should be a whole lot easier for you.

What I did was cut the plug off the lead from the amplifier (when I got my set, someone had already spliced on an Airtronics plug so I just cut that one off). I got a Futaba "J" aileron extension and cut the plug off the end of that. I stripped back the wires, put on some lengths of shrink tubing on each wire, and a medium length of shrink tubing over all 3 wires. Then I soldered th wires together matching "red to red", "black to black" and "white (on the "J" lead) to orange" (on the amp lead). Pulled the shrink tubing over each individual wire connection and shrunk them down, then pulled the larger shrink tube over the 3 connections and shrunk that down. Plugged the lead into my "retract" channel on my Futaba Rx, powered everything "on" and, viola! - retract function with a flip of the switch. Too cool!

I love the fact these retracts take approximately 4.5 seconds for the full travel time from extended to retracted (and vice-a-versa). Slo-o-o-o-w and scale like.

I don't know anything about the Hitech Flash system so be sure you know which wires to splice into. I think most modern radios are similiar but I only know about my own stuff for sure.

Check out this link:

http://www.fatlion.com/sailplanes/servos.html

Scroll down aways to see a comparison chart of different connectors. It looks like Hitech is similiar to Futaba "J" except instead of a "white" wire they use "yellow". It looks like the "yellow" wire would be the one to splice to the "orange" wire on the Multicon amp, then just match "black to black" and "red to red". Does that illustration look like your plug?
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Old 02-16-2003, 11:40 PM
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Default Multicon Amp. compatable w/modern radio?

Proptop,

There were a couple of other things I meant to say about the Kraft Multicons.

Because the 2-pin plugs going from the amp to each retract unit is reversable, reversing the plug changes the retract direction (up or down). One might think that's not a really big deal but if, while plugging everything together at the flying field, you happen to attach at least one of them backwards, when you power on your Tx and Rx, any unit hooked up backwards would retract with the model on the ground. The instructions state the units can handle just about any load EXCEPT if they are not locked in the up or down position. Damage can occur (so the instructions say) if weight is put on the units when they are not locked (like if they were in progress of retracting). So be sure to watch and match the wire colors together when plugging everything together at the field. Also, you need to make sure the retract switch is in the "down" position BEFORE turning on the Tx (see below).

I don't know about you but I find myself to be rather "heavy handed" when handling my Tx. My hand or fingers will occasionally brush against some switch or trim. I've got to really watch myself before takeoff so I don't go with something in the wrong position. Having a trim or dual rate out of whack may not be catastophic, but accidently bumping the retract switch sure would be if the model is sitting with the engine running, taxiing or beginning a take off roll! I'm looking into putting some sort of switch guard on my retract switch so I have to make it a conscious act to activate it!
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