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Uprading a Futaba Attack Transmiter with the DHT

rwalker

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Hi folks. Here is my first tutorial on how to install a DHT module into a Futaba Attack 4 channel transmitter. Since the introduction of the DHT DIY module I've grown attached to them for their price and ability to give you wide range of receiver options. Without further ado, let's get started. Here we have a factory fresh unused Attack Four that I found at a thrift shop for the bargain price of $25.99 less 30% off. It had all the original equipment and three servos.
0909181516.jpg


First thing we do is remove the battery so we don't have any "magic smoke" experiences. Remove the four screws that retain the case rear, then unplug the battery from the power connection. Once opened up, you can see the main board. Get an aileron extension, cut it in half, strip and tin one half with solder. Solder the black wire to GND, the red to PWR and the white to PPM (shown in yellow)

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Here's what it looks like:

0909181716.jpg


Next drill the holes for the bind button and LED board near the top of the rear case. I find using dividers to find hole spacing the best way to mark the holes. I pilot drill then make larger holes to insure the two will center and the button will move freely. I chose to attach my board using .125 plastic strips hot glued to the board, then the case.

0909181636a.jpg


The DHT module is hot glued in the center of the rear case. This is the best place to ensure there is no interference with gimbal movement.

0909181616.jpg


The toggle switch can be drilled and placed on either the front or rear base of the antenna mount area, In this case I chose the rear, and it fit there nicely. A step drill will give you control and positive results for the switch hole.

0909181616a.jpg


Next we modify the antenna mast for the SMT coax antenna. Using a razor saw, cut off those rings at the top. I call them "Jetsons Rings" because that show was full of them.

rings.jpg


After cleaning up the surface, run the SMT through and drive the nut down with a plug wrench. Use a flat tip screw driver on the other side to keep the SMT from turning.

0909181631a.jpg


Solder the other half of the extension cable to the DHT module. The white cable will join to the DHT's yellow cable.

0909181621a.jpg


You can now connect the two leads and do a check by plugging in the battery and switching on the TX. The LED should be lit. If dull, move the toggle to another position. In telemetry mode you will hear the beep. If that is successful, you can close up the TX. Attach the antenna and you are almost done.

0909181637.jpg


The final and most important step to do is to remove the old crystal. Remove it from its retainer and put the retainer back with hot glue.
 

rwalker

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Can this be done with an old Futaba Attack 2 channel TX as well? I would to have a vintage 2 channel TX to fly a vintage RC glider.
Yes it can, if the board has the same layout. There is someone who did it on facebook 2.4 conversions page.
 

Wayne

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Yep, pretty much any transmitter from about the 60's on can be converted.

Nice instal and thanks for sharing. By chance did you see the XHT mod in another thread? (making an XHT from an XJT.) Would give you even more receiver options. :)
 

iflylilplanes

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I've got an Attack II transmitter, the cream coloured one, I'll have a go at the conversion.

Converting 3 early 1960's transmitters, 2 are push button single channel and the other is a pulse proportional set (rudder/throttle) with throttle on a button. I'm after a challenge, learning to fly rudder only on a button, great fun.

Many Thanks,
 

Wayne

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We have a local vintage club, some of the guys are running button transmitters. :)
 

iflylilplanes

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It's early days for me yet, I've managed in the few flights I've had on the button (rudder only) to do one sort of loop, and barrel rolls e easy and I even managed to land back at my feet once. A great feeling, considering its all done with only a button, this is where I found out about the growing interest in vintage RC http://www.singlechannel.co.uk/
 

Retired

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Good diy conversion.

Just a tip. If you are staying with D receivers you can just unplug the toggle sw as it’s in the open /center position.
You can also remove it but use the wires to connect to a 3pin servo plug. Route the servo plug end into the battery compartment if it has a removable cover and use a matching servo connector as shorting plug to change modes for non D receivers or for updating fw if needed.

The bind button if the led isn’t necessary to look at, I don’t, can be any push button or sw closure. I’ve used the trainer sw for that to avoid adding a button. Just parallel the bind button on the sw board. Use shrink tubing on the board and leave it inside the case.

As Wayne posted, for a little more $ you can add a diy XJT solder in module that will allow you to use D and X receivers and fcc or EU firmware.
It’s being called a XHT with hopes Frsky will release one.
Maybe not for a inexpensive tx conversion, but for a more expensive high end computer type tx, it can be a good option for a conversion.

Single channel flying in the day was actually not bad. Having few choices, being able to have rudder, kick up elevator, and hi/low throttle all from one button being pushed was a rewarding challenge.
I flew it in 049 Ken Willard School Boy Kit. Rudder and kick up elevator.

As was as long as you wound up the rubber band on the escapement enough times to last longer that the motor run, you were ok.
It might be fun to try modern day single channel flying knowing there’s no rubber band to wind or run out of turns.
I’ll check out the link.


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iflylilplanes

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When it comes time to convert the Attack II I'll get myself a Diy XJT, I was thinking about that switch cable and will replace it as you say with a servo plug set to D type receivers.

My first trainer I built in 1973 was a Ken Willard Top Dawg, powered by an RC Super Tigre G20/15, no silencer, just an exhaust shutoff that turned with the throttle lever, rudder, elevator and throttle.

I clocked up over 700 flights, 20 x 6 minute flights every Sunday, learnt to fly inverted on rudder/elevator. I plan on building another one day.

If you want to try single channel without building a transmitter I have a program for the Taranis that uses the training switch as the button, it works just like the button only you pull it, one for right rudder, two for left and three for kick up elevator, I made a short video on a rudder only model showing the Taranis in operation,
the good thing about it is if you loose co-ordination you can jump straight back on the sticks, both work at the same time.
 

Oilngas

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When it comes time to convert the Attack II I'll get myself a Diy XJT, I was thinking about that switch cable and will replace it as you say with a servo plug set to D type receivers.

My first trainer I built in 1973 was a Ken Willard Top Dawg, powered by an RC Super Tigre G20/15, no silencer, just an exhaust shutoff that turned with the throttle lever, rudder, elevator and throttle.

I clocked up over 700 flights, 20 x 6 minute flights every Sunday, learnt to fly inverted on rudder/elevator. I plan on building another one day.

If you want to try single channel without building a transmitter I have a program for the Taranis that uses the training switch as the button, it works just like the button only you pull it, one for right rudder, two for left and three for kick up elevator, I made a short video on a rudder only model showing the Taranis in operation,
the good thing about it is if you loose co-ordination you can jump straight back on the sticks, both work at the same time.

Please post your single channel Taranis program, I'd like to give it a try. Thanks.
 

iflylilplanes

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Here is the single channel mix for the Taranis, you just treat it as a normal setup, adjust servo direction, sub trim and end points.

On the sticks, you have proportional rudder, elevator (with down) and throttle.

On the trainer switch, you have one click and hold (move to on) right rudder full throw only, two clicks and hold (on off on) left rudder full throw only, and lastly, three clicks and hold (on off on off on) kick up elevator full throw only, no down elevator.

I made voices saying "right rudder", "left rudder" and "up elevator". I use the voices to train at the pulse speed on the switch.
 

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Oilngas

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Here is the single channel mix for the Taranis, you just treat it as a normal setup, adjust servo direction, sub trim and end points.

On the sticks, you have proportional rudder, elevator (with down) and throttle.

On the trainer switch, you have one click and hold (move to on) right rudder full throw only, two clicks and hold (on off on) left rudder full throw only, and lastly, three clicks and hold (on off on off on) kick up elevator full throw only, no down elevator.

I made voices saying "right rudder", "left rudder" and "up elevator". I use the voices to train at the pulse speed on the switch.
Thanks, Dave!
 

Retired

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Thanks, I’ll give it a try on the bench and see what plane I have that will work ok as a single ch one. Maybe a easystar test plane I have?

I flew a one button tx, but later I used a cheater with a stick.
It was an improvement over pushing the button.
It had clock works contacts driven by a spring and a governor.
The governor kept the on off pulses for the single right rudder, 2 for left rudder and 3 for kick up elevator in sync with the escapement governor.
Also as I remember a quick blip button that gave the throttle escapement a on off (alternated) command from the escapement to the throttle escapement.
A lot going on from a rubber band powered main escapement and a aux throttle escapement.
I later used I think, a Royal brand single channel motorized escapement ( like a servo) that replaced the rubber band escapement and also a throttle version.

I’m thinking a otx mix that would give one pulse and hold for right stick, 2 pulses and hold for left stick, and 3 pulses and hold for kick up elevator would duplicate the device I had.
High low throttle would alternate a quick blip pulse for high low throttle.
Or be enabled by a tx sw to be positional (on/off) or proportional
A tx switch could be programmed to select single ch mode or full proportional mode.


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iflylilplanes

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My home made button transmitter works just like you say, but, with a few extras, servo reversing, switch between sequential and compound escapement emulation, two or three position throttle and timed throttle run if wanted, all programming changes can be made with the single button, I even fitted it with a buddy box.
 
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