Martyn, is this better?

KC

Perfect!

Excellent! Looks like I have some soldering to do.

Thanks Martyn.

Finnspeed, let me know about the FET's. They're just laying around looking for a home.

KC

Nice work KC! Glad to see this thread is still alive. Just proves what great gear Silverlit designed for the AA.

With the right mods (thanks to Martyn and others) IMO it is still the most versatile and best low cost gear out there even today.

Rob

man im glad this thread got bumped up recently or i would have missed it!!!

excellent work guys..... its still way over my head, but its goin in my notes none the less......

id love to do a FET mod like this, but tweak it with the actuator version on the AA toolbox.....

if i can find a way to get my hands on some of these, they'd go right into my P-38, and my micro puddle jumper!!!!!

KC, thanks. I could try it, I have one AA RX stuffed in a Tyco capacitor enclosure - I got one of those P-51s when they were $5...

I think you have my address, right? I could take 2 or 4 of your FETs if you really don't need them.

I just cannot guarantee when I have time try it since my moving to overseas comes closer and closer...

I'll send them out with today's mail. . I still have your address. You'll love the FET's

I read awhile ago, in another thread, that you will be going to Finland this summer. But I thought it was just a trip. Are you moving permanently?


KC

Ok.. Here it is. The conjoined IC's separated and rewired. The "Low Speed Throttle Mod",( LSTM).

Pic. #1: ONE, 74LS74, for the 50% duty cycle. This was tested and this will pulse the motors at ~3X/sec.

Pic. #2: Two 74LS74's, for 75% duty cycle. This pulses the motors at ~1.5X/sec.

Pic. #3: Close up of the wiring for the 75% duty cycle.

Pic. #4: Momentary switch to turn on/off 75% duty cycle while LSTM is on.

At first, the mod did not work. I rechecked the wiring and everything was correct. After a bit of pondering, I remembered pins #7 and #14. Common and ground! Both 74LS74's need to be connected to common and ground.

Martyn, this is great!

I haven't had a chance to fly the plane with this yet, but the bench tests look promising!

Three levels of switchable throttle control! 50%, 75%, normal!

Kc

Congratulations!

I have wanted to try this 75% mod for some time. Looking forward to your flight report.

I was amazed at the precision of your wiring.

I usually just piggy back the chips and use jumpers dead bug style. My mods are usually not so pretty.

Thanks Martyn. More people should be doing this mod. It's a hoot watching/listening to the motors pulse.

The next Tx I mod, I'll try the piggy back style. Once the cover of the Tx goes on, the wiring can't be seen anyway, but for this one, the whole world was watching.

KC

Ok, flight report on the 50/75 duty cycle mod..... and yes, this is long over due.

I did the 50/75 duty cycle mod on my Jet scream tx. I really like this Tx. This Tx has great range even with just 6 NiMh's. And doubling all the plane's antennas gives more range than I need. It has a built in channel selector and the Zero Throttle mod is super easy to do. Now this Tx is totally PIMPED OUT!

The attached pics shows the solder points for pins #9 and #3. VDD for pin #14. Battery neg. for ground.

Pic 2 and 3 shows the one tract that needs to be cut and the wire to pin #9 soldered. The wire going to P11 is for the Zero Turn mod.

All the flight tests were done on 4 Sport planes. One of the planes was the FET modded plane and wore Star Scream landing gears. One of the stock Sport plane also had SS landing gears.

The 50/75 mod is a must for the FET modded plane. With the 50/75 mod turned off, the FET modded plane was uncontrollably too fast. With the 50% duty cycle on, the plane would climb as a stock plane would on fresh batteries. Activating the 75% duty cycle with the momentary switch made the plane climb at a pretty good clip. Trying to land on the landing gears was still tricky. The plane still flew too fast, even at 50% duty cycle for controlled landings.

The most fun I had flying with the 50/75 duty cycle mod was on the stock Sport plane with the SS landing gears. At 50% duty cycle, the plane has a perfect decent rate for a final approach for a LG landing. Fly the plane normally, then at about 100ft feet out, 5 feet high, turn on the 50% duty cycle and just watch the plane slowly descend to a perfect LG landing right to your feet. If you miss judge the landing, pressing the 75% duty cycle button will give you a fairly good climb out to go around for another try.

This mod gives you so much more throttle control, its just simply amazing how much more fun it is to fly. Thanks Martyn for a great mod!

KC

Thanks for the great report. I guess that I am going to have to get out my soldering iron and add another chip to my transmitter!