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Kraft electric retracts

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Old 08-04-2003, 01:47 AM
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SkyKnight
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Default Kraft electric retracts

Does anybody know how to hook-up or convert these retracts to use with a JR or Futaba radio? The retract controller is installed and connection to the retracts is good. I can't figure out how to connect a battery to the unit or the unit to the receiver. Any help will be appreciated.
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Old 08-04-2003, 03:13 PM
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linclogs
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Default Kraft electric retracts

Commet --

Kraft made a couple of different versions of their Multicon Retracts. First, you'll need to determine which version you have.

The older Multicon's can be identified by the color of the leads coming from the amplifier and going to each retract unit. If they're red and white, you have the older Multicons. If the leads are red and black, you have the newer (and more desirable) ones. Also, the lead which plugs into the reciever is a 4-wire lead on the older amplifier - the newer one has only a 3-wire lead. And, the working voltage is different - the old units use 2.4 volts, while the newer ones use 4.8 volts. Because of this, the 4-wire plug, 2.4 volt version is only compatible with a few radio systems (older Kraft 4-wire systems, Heathkit, and PCS). So, you can't hook up the older amplifier to a modern 3-wire receiver.

If you DO have an older set, they CAN still be used with a modern receiver - you just cannot hook them directly to the 5th (or, "retract") channel of the receiver. You will either have to make a mechanism where your 5th servo will manually operate a switch which controls the direction ("up" or "down") of the retracts, or set up a switch that can be activated by the throttle pushrod with "high" and "low" throttle trim set to activate the switch. Then you'd need to wire in a separate battery pack to the switch to provide the 2.4 volts. By using the throttle trim method, the units can actually be used with just a 4-channel radio. But obviously, if you have the newer set, it's a whole lot easier to just be able to plug the units directly into your 5th channel on the receiver.

If you have the newer set, simply cut off the original Kraft 3-wire plug and splice on the plug that matches your modern receiver. I use mine with Futaba gear and for that, you just match up the red to red wires, black to black, and Kraft's orange wire to Futaba's white wire. Plug into the 5th channel of the receiver, power the receiver and transmitter on, and hit the retract switch on the transmitter. The retracts are powered directly from the 4.8 volt reciever pack. It doesn't require a separate pack. However, remember that you are now adding additional load to your whole flight pack, so I'd recommend going to a larger pack - perhaps 800 mah.


Information on one sheet of the instructions state the units are, "Fully enclosed and self-contained within a very rugged and light reinforced nylon case, it is virtually indestructible and fuel-proof".

But you must take care that the retracts aren't accidently activated with the model sitting on the ground. Kraft's instructions also state, "The gear train is protected from shock and damage only in the up or down position. Therefore exercise care while the gear is moving from one lock to the other. Great care should be taken to make sure the transmitter is not turned on with the landing gear channel in the retract position while the model is sitting on the ground. If this happens, the gear will retract under the load of the model and the unit's gearing may be damaged."

Hope this information helps. If you'd like a copy of the manual (once you've determined which set you have), let me know. I'll Xerox one and mail it to you.

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Old 08-04-2003, 03:47 PM
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Default Kraft electric retracts

man linclogs, you sure know a lot about Kraft retracts.

I have a couple sets too. They are great. They made an A set and a C set when I bought mine. The A set wasn't useable with Futaba. I spliced wires like you said, many years ago and they smoked. I took them to a friend and he opened the amp and opened his and changed all the stuff on the board to match his C set and they worked well. Still do to this day. I found an extra set less amp at a swap meet new for $10. Bought them just in case one ever fails. I don't like to fly them off grass, but have. I like them.

Commet, you will like them when you get them going. Don't run them inverted. They are not geared to work that way and really struggle.
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Old 08-11-2003, 09:57 AM
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Default Kraft electric retracts

It appears that I have the newer set since the wires are red and black. I made the wire splices but my amplifier seems to need a battery connect to it. The only way my gear operate is if I reverse the polarity of the battery feeding the amplifier. They will cycle all the way up and down upon switching polarity. The retract switch, channel 5, will not operate the gear. Did I miss something? They have a really nice scale speed and positive locking! Are these gear still available? Hopefully you fellas can help me get them going. My other option is to retrofit mechanical retracts. Really hate to go through all that plus it will spoil the plane.
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Old 08-11-2003, 12:53 PM
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linclogs
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Default Kraft electric retracts

Something's not right if, when hooked up to your receiver, they don't operate correctly. Your 5th (or "retract") channel should operate them. They don't require a separate power supply and will work off the flight pack, assuming everything about the amplifier and wiring is up to snuff. If it's not, then maybe either there is an open wire, or something wrong with the amplifier.

The amplifier provides the voltage to determine the direction (up or down) of the units. Obviously, if you can get the retract units themselves to function by applying power to the leads, the problem must be with the amp.

Kraft went out of business years ago (victim of cheap imports - NOT because they didn't make quality equipment). It's possible you ask someone that still works on Kraft radios to look at the amp (Radio South, for instance - www.radiosouthrc.com).
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