Sanwa PCM1 & PCM2

[Barry Vernon]

Hi Guys

I'm a newbee to RC Helis and I've got an RD6000 Super RC kit along with a Raptor V2 and Futaba gy 401 gyro. The RD6000 came with a PPM RX but is capable of using PCM (PCM1 & PCM2). I was thinking of getting a PCM RX for my Heli due to its reliability but I am not sure what RXs would be compatable. Do I have to use a Sanwa PCM RX or could I use a Futaba 1024 RX. What does PCM1 & PCM2 mean?

Any help or advice on this would be much appreciated. I've done the usual searches on the web and that has confused me even more.

Many Thanks

[Alan Dunstan]

Barry - Unfortunately PCM Rx's are only useable with their own manufacturers Tx equipment, unlike the PPM Rx's which work to a standard. Each manufacturers PCM setup is however proprietary so you can't mix and match Rx's.

So as you have a Sanwa RD6000 Super you have to buy Sanwa PCM Rx's if you want to use PCM. As far as I am aware they only have the one available, the 8129, and pricey compared to some PPM ones at around £80. However it is an extremely good and reliable dual conversion 8 channel Rx and is ideal for helicopters. Note dual conversion. Dual conversion crystals are £15 each.

I also use Sanwa equipment with my helicopters and the GY401 gyro. When I started with helicopters I used a JR PPM Rx initially but after the 1st lockout I suffered due to interference (fortunately the JR Rx on getting interference simply stayed at the last good signal so as I was in a stable left hand turn at the time it carried on doing the left hand turn and came back under control about 5 seconds later. Phew!!!!) the Rx cost at £80 was a nothing if it meant I kept control, and from then on all I have ever used in helicopters are the Sanwa 8129 PCM Rx's, and I have never even had a glitch since. I run all mine on PCM1. I have no idea how PCM2 differs and the manual doesn't tell you either.

You will find however that the helicopter cadre will tell you that Sanwa is no use for helicopters as it doesn't have the functionality or programming etc etc. Absolute rubbish. Within the limitations of only having 6 channels on your Tx you will find you can do anything that the other Tx's can, but you will need to discover lots of it by yourself, as no one else will know. So if you need to know things post it on the forums, here, RCMF or Run Ryder are the best for helicopters.

One other thing. Use good quality servos in an i/c helicopter, especially on pitch with plenty of torque and ball raced. Not £6 cheapies. Digitals if you can afford them. The difference they make is amazing and when you have had no problems with them years down the line you will realise what a good investment they actually were.

 Hope this helps

[Barry Vernon]

Thanks Alan a lot of useful info there. I've been told that the jr649s PCM rx will work with PCM2 but I think you are right, I might aswell invest my money in an RX that I know will work and give me the added security of a PCM failsafe in case I get any glitches.

[Alan Dunstan]

Ah Barry you now open another can of worms. How do you set a failsafe in a helicopter? Answer It all depends what you want it to do if/when it loses a signal, and thats where this subject gets tricky and emotive and no one is right and no one is wrong. Tread carefully with failsafes in helis.

Best of luck in learning to fly them.

[Former Member]

[This posting has been removed]

[Barry Vernon]

Thanks Guys, thats something I didn't really think about but now you mention it it could be a double edged sword! Either way it could end up with a heli doing something dangerous if it had a glitch! I guess thats what flying site safety precautions are for. Should I consider replacing the RD6000 with 2.4 Ghz system? What are the chances of getting glitches on the modern equipment?

[Alan Dunstan]

Barry - I have used Sanwa PCM1 now for years and never had a glimmer of a twitch with it in multiple helicopters. I also use the same Sanwa gear, with PPM, in all my power planes and have never had any problems in many years except that single experience described above with my helicopter when I started with them some years ago. I found out afterwards that everyone else flying there knew the site was very prone to interference on PPM due to a phone mast being only around 100 yds away, and in consequence everyone else was already flying PCM exclusively with no problems.

So the problem with running PCM, or I believe 2.4Ghz currently, is that they are all proprietary. eg if you run Sanwa PCM you need Sanwa PCM Rx's. If you run Spektrum 2.4Ghz you need Spektrum Rx's. Thats the catch with all of them.

I also use a 35 Mhz Multiplex set with all my gliders (because the software allows you to mix and do anything to anything) and use a complete mixture of Rx's with it from the Multiplex IPDS to JR, Schultze, GWS and Hitec and have never had any problems with any of them.

So for myself I would say that with any modern equipment, be it 35Mhz or 2.4Ghz, unless you are likely to be flying at a site with known problems any good quality kit would be ok, and the Sanwa you have is good quality kit. If you are worried about interference get a PCM Rx. It's your cheapest option. Otherwise if you can afford it ditch all your existing 35Mhz gear and splash out on 2.4Ghz. But remember its proprietary (like PCM) and I haven't heard of anyone managing to shoehorn 2.4Ghz Rx equipment into a really tight glider yet.