My Single Stick Project

an ongoing development

or how I got this far!


This represents my latest shot, at a target, that has been moving for at least 30 years of my involvement in RC piloting.


My original goal was to purchase a radio system that would allow me to enjoy flying RC aircraft as much as I had enjoyed flying Control Line models, in the early 60s. As I am a Right Arm amputee, a Single Stick Xmtr. seemed to be the logical answer. My first radio was an ACE Single Stick Silver 7 system kit. It was affordable and ACE graciously supplied a blank case so I could position the various controls as I saw fit. At that time, every SS manufacturer had a layout designed for a right handed, 2 handed operator. A few years later ACE produce a few LH Xmtrs to try and fill that vacant niche but those were still designed for 2 handed operation. There was nothing on the market to fill my particular needs or similar needs of other amputees be they Left or Right. Two stick radios offered “mode options” but required both hands for operation. The thought of flying a rudder only or Coupled Aileron Rudder or anything short of full 3 axis control or had no appeal for me.


At this time (mid 80s) RC was flown with AM radios, making early use of solid state electronics, boasting new levels of reliability and substantially lower costs.


PCs were still uncommon in the home and NiCd batteries were a “cutting edge” power source. Radio systems had progressed to reliable simultaneous proportional control. A huge jump from single channel, escapement driven controls, with vacuum tube Xmtrs and Recs of the 60s.


I began building my ACE S7 SS system. Armed with machining skills gained from auto maintenance, soldering skills from several Heathkit projects, CAD skills from my current employment and modeling skills from control line projects in the 50s & 60s I began this quest.


I mirrored an ACE RH SS layout but located the throttle up and to the L of the stick base. The L end panel got most of the “extras” and R of the stick got the PWR sw and things you don’t need or use in the air.


Things I learned building the system:

PC boards require more skill than point to point wiring projects.

Servos are a big pain to build and were not as reliable as “store bought” servos.

ICs are easy to “fry”! (NiCds are quite powerful)

Receiver board is very crowded and all the components seem to have, at least one, not quite identical twin.

A pencil soldering iron is a must (2 sizes preferable)

ACE had the best customer support in the world.

ACE kit solder is better quality than anything I have ever used.

An illuminated magnifier is a good thing to have.


Things I learned flying the System:

Control Line experience was only useful in pitch control.

Ail, Rud, Throt control, combined with altered viewing positions created whole new worlds of pilot error possibilities.

There is NO tactile feedback, as there is in Control Line, flight so eye contact must be maintained. Searching for trims can be hazardous.

My aircraft choice was neither, sturdy, or easy to fly. Even my experienced tutor had some problems with it. It was a short lived, frustrating, underpowered, molded foam POS airplane that we managed to “force” into the air several times.

The ACE S7 radio system was 100x better than the plane or pilot.


A Telemaster 40 trainer was built. With a reliable plane I discovered faulty E axis accuracy caused by the plastic ACE economy gimbal!

Small movements around center were actually being reversed. This explained some of my landing issues. Then an occasionally sticking rudder knob, followed by an erratic servo, prompted much advice from “experts”! I became convinced that a JR PCM 9 Single Stick system would provide me the best quality and reliability available.


The $$$ JR system arrived and after checking it out, I was very impressed with the feel of the controls and quick response of the servos. All the other bells and whistles just added to this new owner’s “glow”!


ACE supplied me with a blank case of a suitable size and I began the tedious task of “mirroring” the JR Xmtr layout into it’s new case!


JR, as it turns out, was not the least bit interested in my project and refused to provide any circuit diagrams or answer any technical questions. Even the apparent 9 cell battery w 9.6 V was “classified”!

I carefully logged all wiring color codes for the boards and controls and very carefully transferred all the internals into the new case using a mirrored layout. All holes and slots were cut on a Bridgeport Milling machine after laying out everything in AutoCad.


Believe it or not it all worked fine…..for about an hour. Then the RF/PWR meter pegged with an audible click and all response from the receiver stopped. No smoke, just died. Rechecked all my work and couldn’t find anything. Battery draw didn’t seem excessive. Fortunately this happened while setting up the plane and before it ever got off the workbench. An ACE 4-120 with a OS 120 Surpass Pump motor.


JR Service agreed to look at it but “your Warranty is Void”. They replaced a failed board and returned it to me in working condition. No explanation for the failure was ever revealed to me. “Just pay the bill ($87) if you want it back” and the Warranty is still void! ACE is looking better and better.


First few flights had some random glitching problems with Ail. and Throt. in flight. “Experienced” pilots from the field were all sure that Ail. extensions needed filters as I was using wing mounted servos w longer leads. “Jeez fellas a though FM PCM was supposed to be bullet proof”. Added the filters and things did seem to settle down.

Got comfortable with the plane and system over the next 2 months.


One day I started the engine at idle as usual, nodded to my helper (ok) and reached for Xmtr while still kneeling in front of the plane. The instant I touched the Xmtr the 120 went to hi throttle and headed right for my crotch w a 16-8 at full speed!! Without thinking I stopped it with my left and only hand!! ………………………….

EERIE QUIET,….. PAIN, BLOOD……MISSING END of middle finger, SPLINTERED 16-8, Every finger lacerated!!!


Let’s get you to the ER”!!


What happened!!!??? I didn’t have a clue but I was sure I hadn’t touched the throttle control! I had released the “holder” too early but that didn’t cause the acceleration.

Weeks of healing to ponder it and then finally I repeated the set up of the plane and Xmtr without starting the engine.

If I tipped the Xmtr to a near vertical position the throttle opened fully!!!! Every time….repeatedly. Returned it to Horizontal and idle returned!!! Something must be loose inside this Xmtr.


Carefully I removed the back and began looking and poking. The first thing I noticed was that where there had been matching shiny plated screws holding my circuit board in place, one was now a black screw. OK, I’m picking nits but this not how I built it. The black screws go in the black end panel and they are all black. After removing all the screws and tipping the main board part way out, I heard a faint “clink” from behind the board. Aha, it’s the missing, matching, screw and now the throttle works perfectly. Well, now at least this JR should be reliable. I will revisit that later, but for now it’s doing OK. Morale: Few people are as careful with your stuff as you would be. Take extra care with anything someone else has worked on.


ACE introduces the MP8K and after my curiosity is peaked I buy and build a SS kit from an unpunched case. ACE accommodates my request and even offers to punch it for me if I supply the layout. I don’t have the heart to tell them I’m putting a JR Gimbal in it from a donor SS system that was bought just for the Rec., RF module, servos and battery by another JR fan.


This MP8k becomes my favorite Xmtr ever. The ACE gimbal from the MP8k kit was put into my Silver 7 to replace the horrid plastic gimbal. Holy cow, this S7 box is a thousand % improved! IMHO ACE did themselves a disservice to ever offer that plastic gimbal. Not too happy w their servo kits either but that may be me. I’m pretty good at small things but those babies need a watchmaker and a pot doctor to get right. I still have 1 or 2 that work but barely good enough for a throttle.


Now I have 3 LH SS and they all work well.

JR PCM9 SS LH…..presumably the only one in the world.

ACE MP8k SS LH w JR Gimbal……likely the only one in the world.

ACE Sliver 7 SS LH w ACE metal gimbal. 1 of the few if not only one.

I sold a factory built Olympic V SS LH that I would have kept if I could have foreseen the MS2k on the horizon. I think there a few of these made. Case is too small for a MP8k or S7 encoder but with Gordon’s board it could be beautifully paired w a nice metal gimbal.


For a couple of years I had a radio for each of 3 aircraft and I was a poor enough pilot that crashes kept the hanger below or at that magic number. Not enough practice time.


The Real Flight Simulator comes along and was advertised to work with any JR or Futaba radio with a trainer cord. This seemed perfect as a Winter diversion and skill builder.


Well it turns out that my JR was not “any” JR. “PCM only” is not decodeable. The PCM9 has no PPM option. (it also will not operate anything but a JR PCM $$$ receiver) ACE radio is unknown to Real Flight Sim. tech support. “Your stuff is obsolete and you need new equipment”! We will be happy to sell you a new 2 stick wiz banger with the latest in plastic chrome. No you cannot return the RF Sim. for a refund. Grrrr. Ace has closed up and I’m on my own. More Grrrr!


Someone told me about a Public Domain basic Sim. Available on the NET. I nosed around and found someone in Calif. who was selling Serial cables to link this SIM Pgm to “your” Xmtr. for cheap and included the PGM and a bunch of Virtual planes on a CD. I think it was called FMS or something similar. I called them and the JR on PCM was out of the question but, he was confident that if I could find the ACE encoder Sig, and Gnd., his cable would work. I would have to put the deans connector on myself. What could possibly go wrong? Only got 2 wires. “Don’t hook up to the power, whatever you do”. OK. Send me the stuff. I think this guy wanted to make it work as much as I did. About $20 instead of $200. Gotta love the price.

It came. It worked. Took longer to set up the software than the cable to my S7!! Some days you’re the windshield, not the bug!! Funny part of this event is that the same cobbled cable worked for the RealFight SIM using the S7 thru their Faux Xmtr + their JR cable. You didn’t hear it from me! Don’t tell tech support. They won’t get it!

Later on I upgraded to Aero Fly Pro and using their cable and in a similar way got it running fine on my MP8k. I have found the AFP to be much more stable on my platform than RF. Also more realistic in flight & taxi responses. Also transportable from one PC to another as it has a hardware lock instead of a software guardian that freaks out if you even change your ISP!


I am now practicing with the SIM and have discovered the MP8k group while searching for the SIM answers. Wow, there are other people out there with MP8ks. I thought I was the only one for a while.

There are actually SS users with 2 hands? No way! Thanks”Cabbie”!


I met Marv Jensen on the net and agreed to make some parts for his version of the “Renowned Chidgy Stick!” (I was between jobs at the time) His drawings / sketches were….. let’s just say somewhat inaccurate. He sent me a “prototype sample” the origin of which is/was not known to me. Between the sketches and that sample I developed a CAD model with most if not all the parts at least compatible. I recognized the advantages of the robust construction and the use of precision parts very quickly. As it worked out, Marv’s requirements became tilted towards lower costs and less precision and more towards appearance and perceived, rather than real, values. This began to remind me of the Futaba SS “look alike” w the JR like poor reliability.

We could not agree and I stopped making parts that I would not have used myself. My goals and his goals were just different.


It is also about this time that the JR gimbal in both my JR PCM9 and my MP8k became afflicted with brittle plasticrapia and failed in exactly the same manner. Base of stick split and base of rudder knob split. “So solly chawlly”. No parts available for your $500 obsolete system. Even ACE, who is now closed, has better support!

Judicious application of JB weld, thread and epoxy patch up things for a while. Next the JR rudder pots get flaky. Apparently the same predestined life span! Nah…that couldn’t be. Now just try to find a rudder pot for a SS JR. By carefully extracting resistance elements from other JR controls (remember that donor) I was able to swap an element with the rudder pot and get “UP” again.


My best hobby shop experience ever (Donnlesville Oh, now long gone) was an ACE dealer and the owner was Bob Laybourne. (sp?) One of the good guys. He was cleaning out junk boxes and gave me 3 gimbals that were made of ??? molded, glass filled black resin. They had sealed Bourns pots in them. He said that he thought they were removed from World Expert radios as an upgrade or warranty repair. He ran a certified radio shop. I had not thought much about them till the JR gimbal failure. Dug them out and though they were at least 15 years old the pots were perfect and the size was close so I fabbed a mounting plate adapter and screwed the JR knob onto the bridge of the WE gimbal! Is this the most cobbled up MP8k ever or what?

Does it work? Really Really well! Not metal but close and the difference is only noticeable when you hit the stops. MHO.

Imagine an ACE MG with soft stops instead of bezel limits.

I have one more but it’s not for sale.

I love those pots but Bourns makes even better ones. The Futaba and JR made stuff isn’t even close. MHO based only on my experience.


My theory about accurate RC flying is pretty simple: The only connection you personally have to the plane is through the gimbal and the pots and only the mechanical part of the pots. The rest is up to the electronics guys like Gordon. If the mechanics are flawed (sloppy, binding, non repeatable) you cannot know about it till after it happened and you see the result. This is far more important than when driving a car or flying a full scale airplane because you cannot feel the control slop or force feedback w RC. When you have sloppy steering in a car you automatically compensate because you can feel it. No so with an RC model. When you see it you are already behind the event. Slop is bad, but twice as bad in RC as it is indirect control. ANYTHING you can do that reduces slop at control input will improve your control response. ANYTHING you can do that reduces slop at servo linkage will also improve your control response. It makes no difference how much resolution the electronics have if the inputs and outputs are inaccurate. The better the electronics the more demanding of the mechanics things become! Everyone sees the value of accurate digital servos but the stick on the box is still analog and pretty much unimproved, for the sake of economy. Most of the sticks have 19 cent pots attached to injection molded plasticrap with minimal if any UV stabilizer and sloppy ball bearings added just to compensate for poor shaft alignment.


Well that about sums up the journey to the Ambidextrous SS that I have yet to complete the wiring on. With the control assignability and a central single stick this should be useful to North or Southpaws with 1 or 2 hands. It will contain a Spectrum 2.4 ghz RF module and be driven with 8 AA NiMh cells. It has a Chidgy based stick w Bourns pots w ¼” shafts. I have taken the freedoms to build it as I see fit and do not claim it to be as originally designed or exactly like anyone’s. It is a one of, like the rest of the radio. The heart is Gordon’s encoder design. You may considerate the conglomerate either as an original or a collection of stolen ideas that I considered well worth while!


Hope I finish this trip before I run out of gas!


Tom Pomeroy





Tom Pomeroy
Tom Pomeroy
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Tom Pomeroy
Tom Pomeroy
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Tom Pomeroy
Tom Pomeroy
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