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Dual Lightspeed Ignition project

dougweil

dougweil

Well Known Member
Howdy folks:

I have just finished installing a dual LSI ignition system in my flying RV-4. I had 280 hrs total time on my Slick mag system. I sold the whole shebang very quickly and have worked for the last month on the LSI project. I mounted the coils on top of the engine and the Plasma III control boxes on the cabin side of the wirewall.

I installed a small 5.4 amp hour Power Sonic battery on top of my current B&C battery. I followed LSI's dual battery wiring diagram.

In ground runs, it is a major change. Runs like an electric motor! Very smooth, just as advertised. I have not flown it yet since we were grounded by high winds today. Hope to fly it on Thurs when I get back from a trip and looking forward to reduced fuel consumption. Photos are here at my Flickr web site:

http://www.flickr.com/photos/n722dw/sets/72157594147109903/
 
Dual electrical woes

dougweil said:
Howdy folks:
I have just finished installing a dual LSI ignition system in my flying RV-4.
Click to expand...

Pirked my ears... While you can fly behind anything you want. I wouldn't personally fly behind dual aircraft electrical-system integrated ignition. (NOTE: wording was careful, all mags are electrical. Duhyah)

I reviewed the LSI wiring diagram, and it is fairly simple/redundant. But what happens when you have an electrical fire in flight? First you'll shut down the master, which will turn off one mag... What if it's still burning? Do you shut down the other one? Eventually, you will. Then you'll be without engine. Now imagine it's night and raining/snowing?

I know... "The sky is falling!" But good engineers (and RV builders) spend more time thinking about how things fail than how they work. Take a step back. From a "system-wide" perspective, the dual LSI setup has added complexity and weight that isn't strickly required. Consider replacing the dual-battery circuits/second LSI with a pmag. http://www.emagair.com

Adding one of these will meet all your objectives and greatly simplify your ignition system. This is a best of all worlds solution, IMHO.


-Bruce
 
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BruceMe said:
I reviewed the LSI wiring diagram, and it is fairly simple/redundant. But what happens when you have an electrical fire in flight? First you'll shut down the master, which will turn off one mag... What if it's still burning? Do you shut down the other one? Eventually, you will. Then you'll be without engine. Now imagine it's night and raining/snowing?
Click to expand...
Bruce,

I would hope that anybody who installs an electronic ignition would absolutely not power it from a bus that is controlled by a contactor. In other words, the electronic ignition should (imho) be wired either directly fused at the positive battery terminal or fused off an always-hot battery bus -- neither of which would be "turned off" if you need to power down your electrical system.

If you have an electrical fire and shut down the master as you mentioned, then the EI system(s) should not be affected.
 
A few Q's on Plasma

dougweil said:
Howdy folks: I have just finished installing a dual LSI ignition system in my flying RV-4.
Click to expand...
Doug a few frivolous questions:
Did you go plasma II or III?
Plan on using the map/rpm/timing displays?
Are you going to utilize adjustable timing cockpit control?
Last, did you use the optional interconnect wiring for dual units?
(I know there is an interconnect for dual units, but not sure the function.
The note says something about optimizing timing if one unit goes off line.)

Thanks

PS: wiring the EI direct to the battery, not thru a contactor as Dan said is key.
 
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George,

Doug and I were project buddies on the dual Lightspeed installations, as we are both in the Twin Cities area, and both installed them at the same time. I'll answer some of the questions that you posed to Doug, and I believe his answers will be the same.

Plasma IIIa systems. I'm not planning on any displays at this time, nor timing controls. The system came with the interconnect wiring, which does as you suggested, advances the remaining unit's timing per some scheme when the other unit is off line. I can tell you that during a ground check there is almost no perceptible change when dropping one off line. I don't have extensive testing completed yet, but in the air there is a bit of a power drop when shutting one down.

I have one unit connected to a battery bus, which is always hot. The other unit is connected directly to my about 2 pound backup battery, which is charged through a diode to isolate it from dead shorts of the main power system.

Regarding the added weight and complexity of a dual LS system, I'll comment on that when I have a bit more time.
 
No mix and match

Thanks Mr. Alex Peterson, you went for the Plasma III. Two follow up Q's:

The III cost a buch more, obviously you determined it was worth it, why?
What trigger did you go with, crank or hall effect?


BruceMe said:
I wouldn't personally fly behind dual aircraft electrical-system integrated ignition.

From a "system-wide" perspective, the dual LSI setup has added complexity and weight that isn't strictly required. Consider replacing the dual-battery circuits/second LSI with a pmag. http://www.emagair.com-Bruce
Click to expand...
Bruce can't criticize you for being conservative and using the KISS principal. However just one point on about the mix and matching different electronic ignitions. General consensus is if you go with dual EI, use the same brand, make model of EI. The main reason is getting full benifit from the second ignition performance wise. With a single EI you can expect 2-4% increased efficiency. The second EI (matching) gives about 1-2% more; these are just rough numbers for discussion.

If you mix and match different EI units, the second unit may achieve ZERO gain, since the two units may not be working together. In the case of a LS Plasma III and a E-mag, the Plasma III will likely over power the E-mag, which basiclly is going along for the ride. You might as well jut use a standard mag.
 
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Dual LSI

Doug, I'm about 1 month from flying my RV-8 with dual LSI. Looks like you've used Bob Nuckolls ideas from AeroElectric Connection. I've designed the electrical system to be two independent systems with dual batteries, dual electronic igntion and dual B&C alternators. There is a crossfeed switch that can be used to connect the two batteries to start the engine. Using two Odyssey 17 ah batteries adds only 5 lbs more than one 25 a.h. battery. After removing the two mags I'm guessing the whole system doesn't weight more is any than the old system.

The LSI are fed from two always hot battery busses. All of the electrical busses are in the front baggage compartment using fuses as outlined in the AeroElectric Connection. The batteries are behind the rear baggage compartment.

I'm interested in your performance comparisons since you've run mags prior to changing to the electronic ignition. I won't have anything to compare to since I'm starting with the EI.

Bill
 
Ah Bruce, ever the optimist, however I have to agree with you on redundancy. Having probably one of the high time Jeff Rose ignitions in an RV4 and a Bendix Mag on the other side, both have offset themselves in safety over the last 12 years. The Mag overall being the weak link and the EI being nearly flawless with only spark plugs as a early problem, now solved.
The EI has no drop on the mag check, advances the igniton to 40 degrees inflight and saves about 1 GPH on average. I can only imagine what 2 systems would do. Jeff Rose designed a 2 EI system for a Long EZ that went up to 34,000 feet several years ago with no turbocharging.
His dual battery setup and low current draw give you over 5 hours of use after alternator failure, similar to the setup above. That number exceeds most RV fuel supplies.....

Mags are 30's technology...long live EI...

RR
 
BruceMe said:
Pirked my ears... While you can fly behind anything you want. I wouldn't personally fly behind dual aircraft electrical-system integrated ignition. (NOTE: wording was careful, all mags are electrical. Duhyah)


Been out of town for a few days and just checked in.

No, my system has been wired and installed as per LSI dual system. Power is routed directly to the EI units from the main and aux batteries. You can shut down the primary electrical system and the EI units still would run since they are wired directly.
Click to expand...
 
gmcjetpilot said:
Doug a few frivolous questions:
Did you go plasma II or III?
Plan on using the map/rpm/timing displays?
Are you going to utilize adjustable timing cockpit control?
Last, did you use the optional interconnect wiring for dual units?
(I know there is an interconnect for dual units, but not sure the function.
The note says something about optimizing timing if one unit goes off line.)

Thanks

PS: wiring the EI direct to the battery, not thru a contactor as Dan said is key.
Click to expand...

I installed the Plasma III since I figured if I was going to go to all this trouble, I'd go for LSI's top of the line unit.

I did not install the timing displays or the adjustable timing controls. I do have the interconnect installed which serves the purpose of each unit knowing what the other is doing and adjusts the timing of the operating system if one is lost.
 
[

I'm interested in your performance comparisons since you've run mags prior to changing to the electronic ignition. I won't have anything to compare to since I'm starting with the EI.

Bill[/QUOTE]


I finished up the installation last Sunday but was grounded due to high winds. I have been out of town all week. I plan to test fly it tomorrow. So far in ground run ups, it is remarkably smooth. I'll post some data shortly.
 
gmcjetpilot said:
Thanks Mr. Alex Peterson, you went for the Plasma III. Two follow up Q's:

The III cost a buch more, obviously you determined it was worth it, why?
What trigger did you go with, crank or hall effect?
Click to expand...

George, I used the direct crank pickup (which is also Hall effect) for the simple reason that there are no moving parts, save for four magnets which cruise around and around on the ring gear housing.

I had the same philosophy as Doug regarding Plasma III - lots of work to install, go with the top of the line.

I've had a few more flights since the last post, and I can without a doubt state that the engine runs much more smoothly than it did with the Lasar system. I did not anticipate that I will save much fuel as compared to the Lasar, but I need more time to collect data. It is clear that I can lean much, much further than I used to (around 30 - 50 LOP was the best I could do with Lasar) if desired, but I need to see what settings deliver what TAS. Ground idle is also much better.
 
Ben,

Keep in mind that I switched from Lasar, so I already had spark advance. However, I believe that my cht temps are running lower with the LS system, based upon a 24/2400 climb to 8500' the other day. I didn't see more than 380 or so on that climb (OAT around 75F). I was running about 8 gph, so probably LOP. I have never been able to keep the temps there during climb without pouring tons of gas in (12gph). Cruise seems to run cooler also for the same fuel burns.

Take all of this with a grain of sand, since I don't have many flights yet.
 
dougweil said:
[

I'm interested in your performance comparisons since you've run mags prior to changing to the electronic ignition. I won't have anything to compare to since I'm starting with the EI.

Bill
Click to expand...


I finished up the installation last Sunday but was grounded due to high winds. I have been out of town all week. I plan to test fly it tomorrow. So far in ground run ups, it is remarkably smooth. I'll post some data shortly.[/QUOTE]
Doug, The only comparison experience I've had with EI is with a Jeep. It had after market EI when I bought it. When the EI developed a problem I reverted to the original conventional ignition system. When I try to start the engine I invariably let off the starter before the engine has started since I was used to the EI starting instantly. I'm hoping the same is true of the LSI.
 
LSI report

Well today I flew my RV-4 with its dual LSI for the first time. I logged 1.8 hours. All in all, it is nice. I have an Aerosport 0-360-A1A with 280 hours total time with a carb. Start is very quick (although it was quick before). Idle on the ground is very smooth. Takeoff and climb is also smooth. In fact the climb at 25" and 2500 rpm is noticable better than before. All oil temps and CHTs were slightly higher than before (CHTS by about 20 degrees and oil temp by about 10). I did not do any "hard climbing" but I will as soon as I can. I made 3 cruise tests at 4500, 7500, and 9500 msl. Without going into detail, the most noticeable point was that peak EGT occured about 20 degrees cooler than before. OAT was slightly above standard conditions. CHTS ran in cruise from 290 to 350 degrees F. Oil temps were around 175-180. At my normal cruise of 22" and 2350 rpm, I could now lean to the lean side of peak EGT easily (before it would run rough right at peak EGT). Leaning to 40 degrees lean of peak yielded around 7.5 gph (before with the mags it would be around 8.3 but beginning to run rough... I would typically richen then to around 8.5 gph). Of course you do slow down if you lean that much. I lost about 4 knots (TAS was around 166 at 7500 and 9500).

Decent was very smooth and no issues at reduced power.

In general I think the payoff is smoothness. If I had fuel injection, I would probably show a better fuel savings (maybe that will be my next project!!). I'll keep flying and putting some numbers together. Alex Peterson and I hope to fly together Saturday and compare numbers.
 
Progress reports

I know this is an older thread, but I thought it would interesting to hear from those who posted with dual dual ei setups. I am currently considering a dual lightspeed setup and a dual battery single alt electrical system and would love to hear from those who have a similar setup.
 
Wow, I can't believe almost 5 years has gone by. I sure don't miss the old days, when I'd have a mag failure, oh, about every 250 hours (Lasar...).

I've got more than 500 hours since putting on the Plasma III system, not a single issue. Nice to chuck the plugs every year, and not feel obligated to clean them. The only additional thing to be concerned with (as compared to a magneto) is to check the backup battery voltage prior to startup to make sure it is good, and again after startup to make sure it is charging.

To me, the idea of using a magneto now would be similar to not having gps.
 
The first 500 hrs were on a single LSE ignition and about the last 600 hrs I have been flying with dual LSE ignition.

I had a problem early on with one of the boxes and leaking hall effect module. When I switched to duals I dumped the module and installed the crank sensor. Zero problems since installing the duals.

I chose to go with a SD-8 back up generator instead of dual batteries for various reasons. Primary alternator is a B&C and it continues to do it job flawlessly so have never needed the back up. I replace the PC680 every 2-3 years just to be sure I have a good source of electrons :D
 
What Ohm on leads?

I'm about to finish a recently bought RV-4 project equipped with dual Lightspeed II ignition on an IO-360. I haven't run it yet, but the previous owner fired up the engine and it ran flawlessly until one of the leads broke, allegedly because the carbon core was too brittle. On those leads it says 800 Ohms. On the new leads that was put on by him, it says 50 Ohms and they are Firewire racing leads. There are regular auto plugs installed.

Do I have the right type of leads?
Anyone got any shareworthy experiences with dual LSII?

MortenR
 
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