Hi Guys,

Thanks for the quickreplies 40% decrease that`s fantastic...!!! that`s really awesome.

That`sbasicallyalmost4 extraminutes of a 10 minute flight? it would be interesting to see if everyone is getting the same percentage of decrease in fuel consumption?

Soo Arch how many flights per galloncan you make with your currentsetting on the CDI?.

Thanks.

i'm now running a 16oz tank now and can go through the Masters pattern 1 1/2 times on a tank.  I can fly comfortably about 12 minutes on that size tank.  When I usually practice I just go through the sequence once and land, just like at a contest, and I can probably get 10 flights per gallon.  Never really paid that close of attention.</p>

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Arch</p>

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Hi Arch,

Thanks for your feedback i really appreciateit.

Ithink you can probably go more than 10 flights per gallon on that level of fuel consumption.It sure helps having Morgan Fuels as one of your sponsors.

Well i`am still debating whitch path to go for my next bird?,but the CDI seems very promising indeed.

Regards.

At current fuel prices, it's a real horse race between the 170 CDI ignition and electricas far as per flight cost goes.That is what I can ascertain by following this thread and speaking to a fellow flyer who

flies electric. If batteries go down in price(which I believe they will)and glow fuel prices increase , the pendulum could possibly lean in favor of electric.

I've used glow fuel since 1960 and it has never gone down in price. Also , we all know that battery technology will continue to improve...I will miss IC for sure and am worried about a big

learning curve ; should I decide to go electric. A friend will soon bring out his 170 CDI and I'll no doubt get second thoughts. There are also many other variables, for sure.

On a 16oz tank you get 8 flights for a gallon if you run the tank dry each time.   I think I'm using about 12-14oz per flight for the masters sequence, so therefore I can probably get 10-11 flights max on a gallon.  It is significantly better than the non-CDI version though when I was using much closer to 20oz for a masters sequence.  </p>

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Arch</p>

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I've had similar results. With a 24 oz tank, I could get thru a Masters sequence plus 2 or 3 additional passes. Now, with CDI, I can get thru 2 sequences per flight. This has made a huge difference in fuel consumption. Oh, plus a smoother idle, less smoke, better midrange, no kicking during starting, easier starting. What's not to like, if you can stand the 3 or 4 oz it adds?

Jon,</p>

I went to a smaller tank...that easily cancelled out the extra 3-4 oz at takeoff weight.  Doesn't change the fact it is 3-4oz heavier dry, but I am definitely lighter at takeoff with the smaller tank, even with the CDI.  </p>

Arch</p>

</p>

With my current skill level in Masters, I NEED the 2nd sequence of practice per flight!

I flew OS 1.60s until just after the Nats last year. The YS fuel consumption and the price of 30% were quite a shock to my system. The CDI has made it a lot more palatable. Of course the power and torque don't hurt either!

I've never liked flying 2 sequences as it flight slightly different the second sequence due to being lighter.  Not that I think anyone could actually tell...its probably in my head, but I tend to just fly once just like a contest.  I just end up flying more actual flights than sequences.  </p>

It is much nicer to be able to stretch a gallon though.</p>

Arch</p>

</p>

Has anyone retrofitted the CDI to a Comp ARF Integral? How much weight had to be added to the tail to maintain your CG and did this change the performance?

How far aft can the module be installed? Fwd, at or aft of the gearplate?

What is your overall impression of the performance after the change?

Colin.

Depends where you have your CG.
I fly with the CG at 155-165, not at 195-205 like the book says. I will simply remove the lead weight I have installed at the firewall to accommodate the CDI.

John

Has anyone had any problem with the 170cdi and 6meter receiver. My first flight yesterday ,range checked normal with engine running, battery in good range. On take off it seem to get an elevator blip and the jumped into the air to about 50 ft went into hold and then rolled over and into the ground. All systems checked ok after crash. Lynn burks

Lynn, sorry to hear about your crash....

Woodie (aka Don Atwood)

Were you running a separate battery for the CDI or was the CDI plugged into the receiver?

John

Hello John: The cdi was plugged in the receiver battery. Lynn ps other peole at the field are running with the same setup but are on 2.4. Lynn

I will be running mine from a completely separate battery. I have polled quite extensively (on and off-line) and concluded that almost all CDI/Radio issues have occured when CDI was plugged into Rx. Virtually no incidents when separate battery is used.
Not sure how the CDI unit is electronically designed, so it escapes me why the 2.4's seem to have an imunity to this issue...my guess is that the transients and harmonics from the CDI unit are so far outside the bandwidth of the 2.4, and maybe quite close or within the bandwidth of the 72/50/53 Rx's.

Sorry for your plane,

John

<div>
</div><div>  CDI instructions are very specific, use a battery connected to the CDI.  I still do not understand why people take the chance, just because the top names do it is not a reason for me, and if they happen to crash because a similar problem , we will probably not know about it.</div><div>
</div><div>  Maybe, after 10 more stories of crashes, people will start using the instructions set up.</div><div>
</div><div>  Sorry for your loss.</div>

Thanks for the reply and you can bet your bottom dollar it will have a separate battery next time in an old airplane. Lynn

Hi All:

I'm using a JR 12x 2.4 and pulling the ignition power from the receiver. No issues at all. Many folks are doing the same.

Question about the Hatori 725 'short pipe'. The instructions say that it's designed for all engines up to the YS160DZ. Does anyone know if it's OK to use this pipe with the CDI 170?

I'm putting a 170 CDI into a model where the Hatori 821 pipe does not fit. The shorter pipe (725) fits well.

Please do advise!

Thanks,

Atul

Weight and ease of operation are the main reasons on why some of us is using only one battery, I'm using one 2,000 mAh niMh plug directly into the rx for over 60 flights without any issues.

The 725 pipe is designed for Hatori 726 header, and the 726 header is only for up to the 110 engine. Therefore, the 725 pipe may not fit the 822/ 823 header, which are for the 160/ 170.

Adrian

Adrian:

Actually, the 725 pipe fits the 822/823 header quite well. The fit is not the problem. I've run the engine with the 725 pipe and it seems fine. Makes a slightly throatier sound. I just wanted to check if it might have any known adverse affect. The performance is precisely the same with both the 821 pipe and 725 pipe.

Let me know if you think there might be any adverse affects.

Thanks,

atul

I've flown the CDI system on two different planes on Spektrum with the CDI plugged directly into the receiver for power. That being said, I would not even think about doing that on 72mHz or 6 meters. I've watched too many people have issues with ignition on gas engines on those frequencies, and go to extraordinary lengths to separate and shield the CID systems from the radio system. 2.4 gHz is so far outside the frequenciy range of noise that CDI's put out that it is essentially immune.

Hello all, my point is, using the rx battery you are taking chances, meaning people has been very successful with it and people have not, no issues known on people with a separate battery, simple statistics.

And when the airplane ends up being above $4000, well , it does not make sense, but as I mentioned in an old post, if your aircraft is on the weight limit, then I understand taking the chance, but if it is not the case, then why risk.

Anyway, we all share information here so we can all learn and take the advantage of other people experiences, that's what's great about the forums in our era.

Cheers

Thanks Don, will try again the proper way. Lynn ps keep those wings level

Here is the relevant paragraph from the DZ170CDIKIT instruction manual, letter for letter (mispellings and all):

"Use 4.8 to 6.0 volt Nied or NiMH batteries with a capacity of around 700mah. Your flight time with a 700mah battery will be apporoximately 5 (five) at 10 minutes each. If you use the Li-ion or Lipo batteries, be sure to use a voltage regulator to reduce the voltage down to 6.0 volts or below."

Now, when they tell you that you can use a 4 or 5 cell NiCad or NiMh battery (unregulated), it means that the operating voltage is actually from about 4.6V (the very low end of a 4 cell pack voltage) to about 7V with a freshly charged 5 cell pack. Their reference to 4.8V or 6.0V is the nominal rating of the 4 or 5 cell pack, and certainly not what you should expect in normal operation for the majority of the discharge curve. If you decide to apply LiPo or Li-Ion batteries with a regulator, you can obviously choose a voltage value in that range. Finally, no where in that paragraph does it specify that nothing else can share the output of the battery, regulated or not.

There is also a diagram that shows a battery, switch, ignition box, connectors and engine. It is a simplified schematic to show you how to functionally connect the different parts. The battery in the schematic represents a source of power that is notated in the range of 4.8 to 6.0V, without even getting as specific as the paragraph that recommends a 700mAh pack. While it does not show one of several arrangements that could be constructed, including sharing a power source with the flight pack, neither does it show the optional voltage regulator that the paragraph clearly allows you to use. It also doesn't show a propeller on the engine, but I did conclude that I would need one. Therefore, if your conclusion is that the by virtue of the simplified schematic omitting a flight pack sharing the power source, then you would also have to incorrectly conclude that you can't use a voltage regulator because the diagram omits that as well.

Here's what it comes down to: as with everything else with RC, especially with larger, more powerful and complex configurations, you need to carefully consider your installation and fully understand all of the operating components individually, as well as how they will interact in the combined system. Provided that you have a radio receiver that is impervious to the ignition noise (i.e. a 2.4Ghz system), and that you have thoroughly grounded tested it for proper range, you will not have RF interference to worry about by sharing the ignition power source with the receiver. The main concern in this case is that you have adequate capacity to power the combined loads, and that if you do use a regulated system, that it is designed to handle the average current load without overheating. For safety sake, I always recommend using redundant batteries. If this is done with this configuration, with properly matched regulators that load share evenly, then you have a very reliable system. As with any RC model, you need to monitor the performance, understand its characteristics and limitation, and maintain the components in order to be successful.