I'm still running a JR 72mhz system with a Li-ion 7.4v battery regulated with a Jaccio 5.7v regulator to the receiver. Just wondering if it would be safe to run a Y harness after the regulator to connect the CDI box or is this ill adviced using the same battery pack as the receiver when using a 72mhz rx ??

Doc

Doc,

I would strongly advise against that with 72. I have always heard to separate ignition components from radio components when using 72. You may can experiment on the ground and see, but I'm not sure how much luck you would have and I'd hate to say when I'm pretty sure you could lose an airplane doing that. Another point, I'd strongly reccomend running the ignition through a switch for safety, even if you're doing nothing more than using it to prime the motor. I wouldn't want to trust that the motor wouldn't start if you started turning the prop with the power on and no switch on the ignition.

I haven't had any trouble whatsoever in 35 flights or so running my igntion directly into an R921 with 12X transmitter in my Partner.

Ryan,

I've got a few questions. I'm running a JR 12x system with a 9 channel receiver (same setup as yours). Got the DZ170 CDI but have not flown it yet.

Questions:

(a) what battery do you run and what is it's capacity?

(b) Also, I presume you are using regulator. If so, what regulator are you using. Is it OK to use a 6V regulator or is a 5.7 Volt regulator (like the Jaccio 5.7V regulator) recommended. The range for the ignition voltage is 4.8V to 6V but I was wondering if feeding it 6V continuously is safe.

Thanks,

Atul

Hi Atul,

The Ignition unit draws 0.32A at 7800 rpm. For a 10 minute flight at full power this means you'll use around 50 mAh, but obviously you'll never fly at full power for that length of time. The battery size will then depend on your setup and tank size.

Bets wishes

Keith

guys, whats the best setup for cdi? I using NICAD 1500mah for futaba 2.4 RX. Can I plug the cdi wire to one of the channels? or use 2s lipoly with a regulator.

I am flying with the ignition plugged directly into a spare port on a Futaba 2.4 Rx (608fs). I have a Futaba micro switch with a ferrite ring in line with the ignition unit for safety . You could use a switch on the radio to activate the ignition but it may not be as safe for priming etc ?

Setup: APC 19x11 cdi prop, 1,500-7500rpm, 30%nitro/10%oil, 460cc tank + 1oz hopper tank using ~ 320cc for a 10min flight in the wind. Needle open ¾ of a turn. 220mah per flight (6 servos/ignition, A123 1100Mah with 5.2v reg).

propnuter, what do you mean by ferrite ring? is it a servo wire with filter like the gyros? what brand of fuel do you use. Thanks

Hi,

Yea a ferrite ring is a filter on the servo wire. In the 2.4 Rx manual it says that a filter should be used for speed controllers etc to prevent interference.
I use coolpower 30% heli LS (20% High viscosity oil) diluted down to 30%Nitro/10%oil.

Shane

Keith,

Thanks for your note. Weight is not a problem for me since I'm not flying pattern - just a 73" QQ Yak (not a pattern flyer - yet!). I'm thinking of putting in a 4500 MAH JR battery pack, which should provide enough backup for all servos as well as the ignition.

Do you use a Switch between the Receiver (9 channel) and the Ignition. I am presuming so. Will a normal JR switch do?

And how about a 6V regulator: is that too much voltage for the ignition? i.e. should one definitely use 5.7V or some regulator lower than 6V? I would hate to mess up the Ignition!

Thanks!

atul

Hi All,
I have a friend here that installed CDI system in two of his pattern ships (Oxai Euphoria and Oxai Inspec).
He wired the CDI box to his Futaba 2.4GHz receivers, thinking that it would work ok.
He asked me to do some measurements "just to be safe". I measured the voltage rail on the receiver with a digital storage scope (100 MHz BW), and saw spikes of +/- 20 Volts or more on the supply rail of the receiver!
Now, if the receiver "likes that" or not, I don't know, but I have a very strong feeling it is not a good medicine for the receiver, especially the very high negative spikes, so my recommandation to him was to use a seperate battery for the CDI (and so he did )
So, be very carefull, just because it works, does NOT mean it will continue to do so !

Hi
Yes it right,,Its me C groen talk about!!
and Thanks ...body
i will had do the same ,to save some weight
but im a chicken

Atul,

I have been using a Fromeco 2600 mAh Relion through a Radio South regulator, regulated down to 5.1v.

In my airplane, I've got 3 8411SA's, 2 9411SA's, and a 368, and I'm seeing about 225-250 mAh per flight with the ignition running through the receiver. I've flown four flights on a pack with no issues, and I'm not too keen on flying much past that anyway on a pack regardless of type. I'm pretty sure Richard Verano has run these motors on an unregulated 5 cell NiCd, so that would mean that it sees more than 6v for a while and hasn't said anything negative about it. In fact, I believe that was his preferred setup. I just bought a Tech-Aero regulator and they come from the factory preset to 6.2v and will be using it with a Thunder Power 2200 mAh LiPo, so I doubt there will be an issue there. Like I said, I've got 35 flights on the motor so far, and no issues. It's been a dream. It's the cleanest, smoothest running motor I've ever had.

I also highly reccomend, and can't stress enough putting a switch in between your receiver and the igniton. It's very helpful for priming the motor, and it's also an added safety factor. I've got a micro JR switch harness for mine, and actually cut off one of the leads that you would use for a charge lead as it's not needed. That swich doesn't weigh much at all, and it's cheap insurance. I don't think I've seen a gas motor without an ignition switch, and this should be treated no differently- it's a very powerful motor.

I have been lazy and have not tached the motor, but I'm running Coolpower 20% heli in it right now, and it will swing a 19x11 with no trouble so far. It's been around 70 degrees when I've flown it, and I'm about 820 feet elevation at my home field. I will get a tach reading on it soon, as I would like to compare numbers with guys running 30%. It's also my understanding that your needle will stay in its normal range unless you're using low oil fuel. My needle is one click over 1 3/4 turn out, and I the last time I flew it I could tell that it needed to be leaned a little more as it's probably close to being broken in.

If you have any more questions, please let me know. If I don't know the answer offhand, I'll find out for you.

Hello Torben,
First of all very nice equipment!!!!!
Second: Can you advise what was the total weights add with the CDI kit?
Third: I am far from being a specialist but is it strongly advised to link the 2 bolds of the landing gear with small carbon piece.
This is in order to better spread the landing touch down strains at the entire landing gear support area.
(See picture)
Good luck
Amram Leshed
F3A Israel

Hi Carston,

have you tried an in-line ferrite ring, as per Shanes' suggestion? Thats exactly the kind of thing an inductor would help with.

Hi Atul,

Here's the circuit I've tried on 35MHz 149 PCM receiver. The regulator takes the voltage down to 5.5V into the receiver and the Emcotec switch regulates to 5.5V also. It worked ok on the ground and for most part in the air. However the model seemed to experience momentary freezing of the ailerons in flight; i.e. when I rolled, it would appear to roll a bit further than I'd input. I've experienced this before with a stick pot fault on my 14MZ tx, so I tried a second Tx but with the same issue. My guess is that the Ignition unit is doing something to the receiver function. So I can't really recommend this approach any more.

I've now gone 2.4 GHz and will adopt Shanes' approach (see post and see how it goes. Does anyone know if YS recommend a particular method for this

Keith

Hi Amram
The toal weights with Cdi / ext.. Bat..( 174g) is 4878g
and You cant feel it when you fly, even with 600ml fuel
its very nice to fly..
and Thanks fore the advise ..

Ryan:

Thanks for your detailed note. Much appreciated.

I talked to Richard and he uses a simple 6V 5-cell NIMH Pack with no regulator. He says that setup has worked fine for him for a while. I plan on using a 4500 MAH JR battery pack with a 6V Duralite regulator that I have lying around, though Richard said one does not really need that. A regulator is needed when using a 2-Cell Lipo since those things when fully charged peak at over 8 Volts or more.

I will include a switch between the receiver and the Ignition unit as suggested. I've got some spare JR Gold switches lying around (not micro - the full sized ones). The header/muffler comes in tomorrow and I'll run tests and post results in the near future. I will be good if someone can post results for 20%/30% with Low/High Oil content (4 tests in all).

I plan on using 20% Nitro and low oil (9 or 10%). I believe people have tested with as little as 7% though that seems to be a little risky.

Does anyone know what the lowest "safe" oil percentage is on this engine?

Also, one final question: what's the best run-in procedure. A fast-idle for 20 mins in 5-min intervals with a full cool-down in the middle? What about run-in props, assuming 20% and low oil?

Thanks in advance!

Atul

Has anyone ran the YS ignition on unregulated A123 batteries?
Thanks,
Jim

Hi
this is the switch i use fore " kill switch"
http://shop.rc-electronic.com/e-vend...t=11&c=39&p=39
just 11g with out all the cabel
so no throtle cut with gas servo
i get the best stabel idel ,, 1500omdr .. the gas servo push a littel at the throtle screw

Hi Keith,
I know that various filters etc can cure the spikes, but when looking at the spikes, they seem to contain a great deal of energy (wide spikes), and my feeling is that there is a need for so much filtering that it makes more sense to mount a small battery to supply the CDI device instead. As I told Torben, he wont get me to "sign the paper" that it is 100% secure to fly with, and he is not going to risk any of his two pattern planes because of that.

Hi Carston,

Thats a great reply and sums up what I feel about the requirements to filter correctly. I guess one question is what level of RF can the receiver tolerate, which is quite a big piece of work. Perhaps its just best to admit defeat; I've gone to a 400 mAh Lipo, which should be good for five flights

Bets wishes

Keith

My plan is to simply solder an extra lead on the battery. One lead will go to the receiver (with ferrite ring), one lead to the switch for the ignition. This way the receiver will not see the ignition RF and I think the battery will buffer away the spikes from the receiver.
Jim

Jim, I would suggest that you do a thorough ground range check first. This may work by diminishing the spikes, but it's not going to eliminate them.

When I talked to Richard at YS he said many are just running it out of a spare port on the receiver with no problems. Others use a separate battery. I hooked mine up through the receiver, but havent gotten a chance to really test as I left for Toledo today.

Arch

2.4 systems ought to be fine handling the noise. I"m not sure what Jim is running, so it's more of a general caution statement.

I'm running 2.4. Who are you?
Jim