[/quote]
Right, you really don't want to start a flight when your average cell voltage is at that point. One thing you have to realize about the way linear regulators work: They function as regulators as long as the input voltage is at or above the sum of the regulator's dropout voltage and the output voltage setting. Once the input voltage drops below that value, the output voltage follows the input voltage minus the dropout voltage.

Both the Jaccio and Tech-Aero regulators use very low dropout voltage regulator chips (about 0.2V), not sure about the others out there. So if the regulator was set to 6V and the battery voltage had dropped to 6V (ignoring voltage drop along the wire for a moment), the output would be 5.8V and so forth. This will vary a little depending on the current load, but not very significantly. That equates to either of them being able to give you a better survivability opportunity as the battery gets really low as compared to a cheaper designed regulator with a higher dropout voltage. However the bottom line is, once the battery gets below a certain point, nothing will save you (except a 2nd battery and regulator).

You've got to know what's left in your batteries before flight by tracking their discharge characteristics in the model you fly, the way you typically fly. Then measure before each flight and stop to recharge well ahead of the danger point. I generally don't go below 7.6V for a 2 cell pack (no load). I hate it when I hear about someone losing a model this way and I sure don't want to have a similar story of my own one day.

Hi All:

I have a rather basic question in the midst of some rather serious discussions so please excuse it's simplicity!

How does one draw the power for the CDI ignition out of the receiver via a regular switch? The power input to the switch is via a female connector but the input to the receiver is a male connector. Does one have to replace the Switch female connector with a male connector? Please advise.

Thanks!

atul

Yes - unless you solder an extra "out" onto your battery, which I think will keep the CDI spikes off the reciever bus.

I installed the APC 19x11 today. The rpms were 7440, without retuning from the Mez 18x10. The prop flies very nice and smooth. I will leave it on for a while.
Thanks,
Jim

Well guys,

When the question comes if it is safe to fly with the CDI, I have to say the following,

You can do it the RIGHT way, the creative way or the WRONG way.

The right way is as per the instructions, use a separate battery, the worst that can happen is a flame out, which can also happen on the glow version (ask CPLR)
The creative way, use one battery and combination of regulator, wires, empty connection on the receiver, etc, using experience, own and from others, and some basic knowledge and common sense.
The wrong way, take the power from a non fail safe "on" regulator on a limited capacity battery, you are going to crash sooner or later.

On my tests today, a 12min flight, took 100mAh from the ignition battery and 80mAh from the receiver battery.

The ignition battery, Flight Power 7.4v 1350mAh was at 49% charge after 4 flights on left accidentally on for 20 more min.[sm=confused_smile.gif]

The Rx battery, Flight Power 7.4v 1800mAh was at 69%.

If you add the consumption on both together you will end up with around 40% or less on the Rx if using two regulators on the same battery, as both will drain the battery in a different manner.

The regulators are really not magical devices, they can't really regulate the output voltage without sacrifice, what I mean is, from the 7.4V around 1.4V will be dissipated as heat, as the energy can only being transformed, there's no way around it, you will use some voltage and burn another, if you have two regulators this will also increase, then add the actual consumption of the powered devices.

So, If somebody wants to use a single battery (I Was planning on that but CG needs made me add another battery), check your voltage and recharge if you are under 60% charge to be on the safe side, if not, then blame yourself if something wierd happens not the CDI.

If using a separate battery, if you are under 5Kg, then what's the big deal? I prefer to be double safe on my $3500 plane than save 50 grs I don't need to save anyway.

I hope this reflections will be of some good to the people that are afraid of the CDI just for what they read here.

Regards to all.

Alejandro Pereira

Thanks, Jim, for clarifying the switch issue.

With the 19x11, what percentage Nitro/Oil are you using to get 7440 RPM?

Atul

If using a 2.4G radio, the idea is to use two batteries, two regulators, not two regulators and one battery. It's a zero-sum game. The receiver and servos draw what they draw at a particular voltage setting regardless of whether the source is one, two or more batteries and/or regulators behind the scene. Add the extra draw of the CDI unit and it's still a zero-sum game, just shifted to a higher average current level. And while it's true that linear regulators dissipate a little bit of heat, that's what you find yourself doing if you want to lighest possible setup (LiPo batteries) with the best peak current on demand (LiPo's again). So you can carry more weight and have a higher internal resistance in the form of a NiMh unregulated, and have your servo performance vary throughout the day, but avoid generating a little bit of heat (barely enough to notice with your finger tip on the regulator body), or you can optimize your setup for all-out performance.

As mentioned before, the key to going home with an intact airplane is to know the performance of your equipment and monitor it scrupulously. Failing to do that will get you into trouble eventually, no matter what your configuration is.

If concerned about using the CDI off the same power system as the RX, then use a separate dedicated battery. You pay a weight penalty, but that's perhaps worth it if it gives you peace of mind.

Here's a question for those interested: Would there be interest in a light weight regulator product that isolated the CDI output from the receiver output, provided for a transmitter selected cutoff for the ignition output, and also automatically cut off the ignition output per some pre-programmed value to avoid running it below a safety margin?

Ed- sounds like a good idea!!

ATUL, I used the regular 30% heli fuel, but forgot to "up" my AFR back to 100% for this prop. Still, at 7400'ish rpms, the power combination is amazing. I never would have thought that I could drop 1100 rpms and still be happy.
Thanks,

Alexandro - thanks for your note as well about the CDI and your battery thoughts. My decision to use A123's is also based on other guys running 50 cc, 100cc, and 150cc gas planes. There are quite a bit of guys running "plane" and "ignition" off of one battery.
Thanks,

Jim

Keith:

Maidened the Yak (QQ, 73", 12 lbs all up weight) today with the CDImotor. The engine would not draw fuel into the injector pipe either via the "180 degree"method described below (it did work on the test bench tough), or via open cranking.Abuddy of mine found a simpler method:Just use a Syringe to push air through the open Fuel tank pipe:this quickly drives fuel through the fuel feed, through to the needle and up the injector pipe!

Here's the debrief on the maiden.

Setupuralite Electronic switch (2 regulators, 5.9V), dual LIPOs (1500 MAH), 15% Nitro, 8% oil. (I'm a sport flyer currently, with an interest in pattern); The batteries were plugged into the receiver (JR 921, 2.4Ghz) and a switch from the receiver powered the ignition. 18.1x10 prop.

After five flights, all lasting 12 to 14 mins, the batteries read:7.6v and 7.3v respectively. The draw seemed to be more from one of the batteries that had "high current"wiring installed on it (though the servos - six 8411's, are not high-current servos). The Asymetric readings seemed a little odd since both batteries were fully charged before the first flight.

Some strange behaviour was observed in starting the second flight:The engine would not start and seemed too rich. Ihad to turn out the pump (counter clockwise)by about 1/4 turn and then it started up properly. On the third flight, another quarter turn out was required.Thereafter, the engine started up well for flights 4 and 5.

Overall result:very satisfying. With the Hatori muffler, however, there is no noise at all so it seems a little wierd. Afriend of mine who has a full-scale Edge 540 says that the big planes just use headers, with no muffler. Is there any problem (other than noise, which is not a problem here in India :-), in running the 170 CDIwithout a muffler?That would make it could much more like a full-scale plane (though the noise would be a bit much Iwould imagine.

This is one great engine for sport flying. Reliable and powerful.Pulls the 12 lb Yak into an unlimited vertical as far as the eye can see. All on 15%. Iguess you pattern guys REALLYuse a lot of power :-).

BTW- any idea where I can get a guide to basic Pattern flying? The sequences, etc.?Do let me know if you have any pointers.

Atul

Ryan:

Hi. Ijust posted a debrief of my first five flights on the CDImotor. Ihave a question on the relationship between the PUMPand the Needle setting.

After the first flight, the engine would not start easily:it would start, remain on idle for a while (regardless of the throttle being opened)and then sag and die. Seemed too rich. So Iturned the pump out (lean, counterclockwise) by 1/4 of a turn and then it started off well.Note that the engine had previously been run on a fast idel on the bench for about an hour (15 min interval runs)on two separate occasions and so was getting "Set".

The same problem occoured before flight #3. Another 1/4 turn counterclockwise and all was fine.The needle setting is at 1 1/8 turn out (just a little more than a turn). I'm running 8% oil, 15%nitro.

Flights 4 and 5 were fine:no starting issues and the motor seemed 'set'.

So the question is:does leaning the pump have the same affect as turning the needle in? Troy's blog (http://www.patternflyer.com/troy/?p=92 :a deep analysis on the Dingo)explains the relationship between the two quite well.In the two cases (flights 2 and 3)above, a lower needle setting did not seem to have much of an affect but the leaner pump worked real well.The pump controls how much fuel goes into the engine while the needle controls the pressure of the 'popoff' valve - so to speak - applied at the pump. So with a leaner pump, one can open the needle more. Is it better to err on the side of a leaner pump and a richer needle, or the other way around?

Any advise would be appreciated.However, the motor works well now.

Thanks,

Atul

Atul, the large difference in the drain of the batteries is easy to explain. This is what happens when you use a pair of regulators that are not precisely matched re. their output voltage. You need to use a regulator product that is specifically designed for this job. That is the reason Istarted making Tech-Aero regulators available. Icould not find what Ineeded in any existing product in order to achieve a balanced draw down of redundant battery packs, so Tech-Aero was born.

Ed:interesting point about the regulator design. Let's discuss this offline.

atul

Ed,</p>

Forgot to thank you for your kind comments about my new plane (other thread).  Anyway, thanks for that, and thank you for making a great line of regulators.  I am very happy with mine.</p>

</p>

-Mark</p>

I am very happy with my dual regulator setup I'm currently running.  After 4 flights on Saturday at a contest, the batteries were within .01 volts of each other and one pack took 4 mah more than the other.  That is pretty darn even as far as I'm concerned.  I'm running the ignition through my receiver, with dual battery packs feeding the receiver.  Working great.</p>

</p>

Arch</p>

</p>

What kind of current draws are you guys that are running it directly though the receiver seeing on a typical 10 minute flight?  What mount are you using?  Just curious to see if there is an average and if it mount specific.</p>

When using the Hyde AR80 I was using between 200-225 on a typical 10 minute flight.</p>

Arch</p>

</p>

Arch:

That is right in line with the current draw Brett has experienced using the YSmount.

hi </p>

I use the YS mount in my Euphoria ,, and the 170 cdi ,,, it use 90-110mah per flight  at 10min..</p>

You are using 90-110 mah for just the ignition or including the flight surfaces?  That seems really low for actually surfaces also.  An electric plane will use 70mah per flight just for the servos.</p>

</p>

Arch</p>

</p>

hi </p>

 yes i use 90-110mah at the surfaces.. and 40-60mah at cdi.. yes i think is low too ,, but the surfaces is no sloppy, i think it ther fore is so low..</p>

its nomaly 90mah  and 40mah ( fine weather,,slow wind)..</p>

</p>

That isn't too far off.  I'm using around 160 mah for both surfaces and CDI with the new Hyde LR 85 mount.  That is his Merle's new mount with the limiters built in.  On the AR80 I was using previously I was using between 200-225 for the same flight period.  I really like the way the new mount works.  The idle is very nice as the engine is basically hard mounted at idle, and as soon as you advance the throttle it slides off the limiters and gives you the full vibration reduction.</p>

</p>

Arch</p>

</p>

Hi Arch,

I've been doing some work for Merle on his limiting mounts and can certainly agree with you that the new LR85 mount is a really excellent product which combines very soft mounting to give great isolation, and movement limiters to prevent excessive motion at idle. I also think the square Alloy beams are a great improvement.

In fact the postion of the limiters are set so that at normal low speed idle they don't have any effect. However when the idle goes very low just before cutting the limiters then work to prevent large movements which may cause the engine to strike the airframe and cause damage. I wish I'd had this mount several years ago as the cowl on my Shadow would still be unmarked!

The other ways the limiters help is when you get large movement of the engine during very fast throttle opening or most commonly if you get the needle valve setting wrong or run out of fuel in the air and the engine kicks.

Finally with the CDi engine using the 19 x11 prop, the LR85 mounts gives excellent attenuation up to full power providingup to 90% reduction in vibration at and above 6500rpm.

Best wishes

Keith

Hi everyone,

Now thatsome of youhave been flying the CDI version for a while can you guys tell me besides the significantly decrease in vibration and smoke trial over the non CDI version is there a drastical improvement in "FUEL CONSUMPTION" over the DZ170???.

My latest YS is a DZ140 and despite that he`s a glowcoholic lol it`s a very reliable and smooth running monster.

I`am about to start flying again and no doubt i`amYS lover butman the price for a gallon of 30%CP Heli has almost doubled hereand i can`t afford to fly 12 flights a week for that amount of$for a gallon now.

Now ihave been thinking seriously of converting to electric but believe me i`am not so excited of doing that..!!!,i just don`t think that flyinga electric powered plane would be the same as smelling the methanol and hearingthe sweet roar of a YS poweredplane?.

If you guys can tell me thatyou definitelysee more improvement on the fuel consumption parton the CDI would really help my decision.

Till now nobody has gone in detail about this topic on the CDI version.

Hope to get some feedback.

Regards.

The fuel consumption on the CDI motor is decreased by at least 30% if not more.

For those using the Hyde LR85, how much does it weigh?

Thanks

Mike Wickizer

Hi Mike,
it `s 92 grams, give or take a gram
without the limiter it`s90 grams
Bryan

I agree with Mike.  The fuel consumtion is decreased by at least 30%.  I'm seeing much closer to 40% on my experience, but that is with a new pattern this year as well, so I"m not 100% sure what is the difference in the Masters pattern and how much is the engine.</p>

</p>

Arch</p>

</p>