Jump to content

Lycoming EIS (SureFly)


chrixxer

Recommended Posts

19 minutes ago, McMooney said:

looking at lycomings docs, you can run 2 of these, 1 just has to have a backup battery.

 

hmm, wonder if i can run one surefly and one of these?

I want to know the answer to your questions too.  I have a surefly and would love to have a second EI! 

Link to comment
Share on other sites

On 9/30/2020 at 10:21 PM, carusoam said:

Double check the allowed timing...

Many MSers would prefer 25° BTDC Over 20°...

I think the IO550 gets 22.5°...

Best regards,

-a-

Which would be better, two EIS at 20° or one EIS at 25° (or variable, but wasn't there a report here that the variable timing was not compatible with high altitude departures?) and one needing IRAN every 500 hours old school magneto?

  • Like 1
Link to comment
Share on other sites

I bought the Surefly for my 0-360-A1A from spruce with the required ACS ignition harness as my mags are Bendix, and the surefire requires slick magneto wires... 

 

I never took it out of the box as my mechanic pretty much insisted that I just go with the old Bendix magneto’s.

 

I’m not a mechanic but I’ve heard the arguments both directions on staying with the old school or switching to Surefly.
 

I read the installation directions and with this magneto you can have variable timing or you can set the timing to where you need to be via dip switches.

maybe in 500 hrs I’ll go with the surefly... Maybe sooner

 

 

Link to comment
Share on other sites

10 hours ago, chrixxer said:

Which would be better, two EIS at 20° or one EIS at 25° (or variable, but wasn't there a report here that the variable timing was not compatible with high altitude departures?) and one needing IRAN every 500 hours old school magneto?


Two mags on identical timing... initiate the flame front in two locations equally...

When it comes to two mags running on different timing... The first Mag to fire will start the burning process, the following mag won’t have much to do...

The reason we have two mags is primarily as a back-up system... but since we have them... what else can we get them to do..?
 

If we had one plug... we would have mounted it in the center of the cylinder... for geometric/volumetric efficiency...

 

As far as variable timing goes... this is great for cruise efficiency... the word ‘variable’ seems to be confusing the conversation...

  • Fixed timing... we use the data plate setting.... to achieve the most HP, safely... (earlier timing starts to generate a lot more ICPs and CHTs...)
  • Variable timing... means we can change it to a cruise setting... in cruise... Then change it back. (Automatically of course)

If we are discussing using a cruise setting during T/O at high DA airports... we have missed something important... It will be hard to get off the ground with cruise power... it will be hard to keep the cylinder heads in place using cruise timing, during max HP...
 

Similarly for TC’d engines... they can produce very high percentages of BHP... in cruise...  So.... there isn’t a lot of value in retarding the timing in cruise for these engines... essentially, an option that only makes sense for low power settings...

Note for the electronic mag builders...: Some MSers will want to cruise using three different modes... Depending on the day, or leg of the flight...

  • Speed and Efficiency... Near peak, at altitude...
  • More efficiency...  Vz
  • More speed... ROP, flaming dragon mode...

N/A engines run into low power settings automatically... with altitude...  Providing an extra margin of safety from the red box... 

Variable timing, is a nice way to increase efficiency, but care must be used as it accidentally puts the engine back towards the red box...

 

So... the preference for some will be...

  • Two mags using 25° BTDC for most HP possible during T/O and ROP climb....
  • Two mags using 20° BTDC for good margins of CHT safety in hot areas of the world...
  • Variable timing, with the base line set @25°BTDC and going towards 60° in cruise...
  • If you have the luxury of two electronic mags set them up the same way...
  • electronic mags are expensive, but last the same period of time as an engine OH...
     

Allow time to pass when selecting new mag technology.  Old mag technology was bad, but really well known... New mag technology is good, but not really well known...

Eeeesh... this is difficult to discuss by typing... :)
 

PP thoughts only, not a mechanic...

Best regards,

-a-

 

  • Like 2
Link to comment
Share on other sites

There is a lot of valuable information regarding electronic ignition systems and variable timing curves in this thread:

https://vansairforce.com/community/showthread.php?t=169923

Keep in mind these guys are using experimental ignition systems that allow them to customize their timing curves but the physics are the same.

The takeaway from that thread is the Surefly timing curve is too aggressive for optimal operation. Lycoming was wise to offer "their" units with fixed timing only.

Link to comment
Share on other sites

2 hours ago, N231BN said:

There is a lot of valuable information regarding electronic ignition systems and variable timing curves in this thread:

https://vansairforce.com/community/showthread.php?t=169923

Keep in mind these guys are using experimental ignition systems that allow them to customize their timing curves but the physics are the same.

The takeaway from that thread is the Surefly timing curve is too aggressive for optimal operation. Lycoming was wise to offer "their" units with fixed timing only.

I’ve had my Surefly on for 7 months now, maybe 50 hours.  It’s on an io-360a1a.  20 degree btdc baseline, advanced timing enabled.

Is it perfect? No.  At altitudes above 10,000’ when ROP, it runs warmer by maybe 10 degrees (cht) which makes sense as the timing is advanced.  Maybe a knot or two faster.

LOP it is definitely better.  I have several knots better speed LOP at higher altitudes than before on same fuel flow.  Cht are a bit warmer than before but still cool since it’s LOP.  

If you run LOP, the advance is nice.  If you are primarily ROP, it’s not really great.  Everything is a trade off.

If you don’t like the the results, you can always set fixed timing and the Surefly still saves money with its 2000hr tbo.

  • Like 2
Link to comment
Share on other sites

13 minutes ago, N231BN said:

FWIW, I just installed a Surefly on my 231 so I'm not trying to tear them down. I only have one flight on it so far but I was able to run further LOP than before at 15.5k. Fixed timing of course.

Glad you guys are trying them on the turbo airplanes.  Even with the fixed timing you may see improved starting and longer life.  If it runs better too, that’s a bonus!

Link to comment
Share on other sites

We have been discussing the value of the stronger spark....

So... if you are able to run deeper LOP... that would be interesting...

Depth of LOP available will be MP related... for an NA engine.... 90°F LOP down low, you may only get 50°F LOP up at 10k’...

Probably not very helpful to lean this much... but it is an indication of the stronger spark working well...

PP thoughts only, not a flight engineer...

Best regards,

-a-

Link to comment
Share on other sites

1 hour ago, carusoam said:

We have been discussing the value of the stronger spark....

So... if you are able to run deeper LOP... that would be interesting...

Depth of LOP available will be MP related... for an NA engine.... 90°F LOP down low, you may only get 50°F LOP up at 10k’...

Probably not very helpful to lean this much... but it is an indication of the stronger spark working well...

PP thoughts only, not a flight engineer...

Best regards,

-a-

Honestly I haven’t ever seen Surefly say that their mag has a stronger spark.  Longer duration?  Maybe.  But I don’t think they advertise the “stronger” spark.  I’m pretty sure Electroair does though but they also use their own plugs.

  • Like 1
Link to comment
Share on other sites

When I spoke to the  guy at Surefly about the Higher Voltage spark which I am assuming means  "Stronger" or hotter spark .  He told me you would see little efficiency from the hotter spark but you get most of the efficiency from being able to advance the timing.  I have heard similar comments/statements from other people on this subject.

They way I understand it is you only deliver so much Joules at one time plus this has to happen short period of time at single event of the 4 cycles of our engine. To clarify term Joules = work or energy, equal to the work done by a force aka Voltage. The Electroair  requires more room to mount more boxes  some in the engine compartment and some behind the fire wall. I don't know about your Mooney but there isn't a whole a lot room left to mount more boxes in my Mooney. I believe that Elecroair requires special spark plug to handle wider gap and higher voltage that Tempest is able manufacture special plugs for them now. I am a similar thing was said about life cycle of dual magneto now problem back then. Starting become a problem now . if Tempest get sold or bought out or decides no value in making specific spark plugs for the certified market or decided too much liability making them.  That could be a problem.

Just my thoughts

 

James '67C

  • Like 1
Link to comment
Share on other sites

A few points about Surefly/Lycoming EIS.

1) The Surefly mag is timed to TDC and dip switches control the base timing. The dip switches are on the engine side of the mag, so you have to remove the mag to change them. Lycoming initially certified the IO-360s with 25 deg timing advance. In the mid-1970s Lycoming  changed it to 20 deg. (except the dual mag versions because of a limitation of the mag). At best power mixture it doesn't make a lot of difference (there's a graph in the APS course that shows that). LOP, the engine runs better with more advance since the leaner mixture burns slower delaying peak pressure. You can change the timing to 25 deg and remark the data plate if you want. See Lycoming SI 1325.

2) Lycoming has no problem with you putting two EIS on the engine. But, that would be a major alteration to the airplane type design and would require an STC. See Lycoming SI 1569A. 

3) Both the Surefly and the mag will produce a "hotter" spark with wider spark plug gaps because the voltage has to build to a higher value before it can jump the wider gap. Supposedly the Surefly will operate with a wider gap than the .022 max Lycoming specifies for the mags.

4) It's an interesting test of the air/fuel distribution and the ignition system to see how far LOP you can run, but hasn't got a lot of operational value. The power falls off very rapidly as you get farther LOP. Leaner than 20-40 degrees and you are not running at peak efficiency (look at the BSFC curve). 

5) The torque output of the engine varies depending on where the peak cylinder pressure occurs. At around 16 degrees or so after TDC the maximum brake torque is produced resulting in the greatest efficiency. The whole idea of the Surefly advance is to try to get maximum brake torque timing at power settings where this will not compromise the detonation margin. Advance starts at about 24" MAP and is fully advanced at about 21" MAP.

Skip

  • Like 4
  • Thanks 3
Link to comment
Share on other sites

On 10/3/2020 at 11:15 AM, Luckybird said:

I bought the Surefly for my 0-360-A1A from spruce with the required ACS ignition harness as my mags are Bendix, and the surefire requires slick magneto wires... 

 

I never took it out of the box as my mechanic pretty much insisted that I just go with the old Bendix magneto’s.

 

I’m not a mechanic but I’ve heard the arguments both directions on staying with the old school or switching to Surefly.
 

I read the installation directions and with this magneto you can have variable timing or you can set the timing to where you need to be via dip switches.

maybe in 500 hrs I’ll go with the surefly... Maybe sooner

 

 

Do you have a part number on the slick harness you used? I have the A1A w/Bendix mags and am putting a SureFly on.

Link to comment
Share on other sites

3 minutes ago, tankertoad said:

Do you have a part number on the slick harness you used? I have the A1A w/Bendix mags and am putting a SureFly on.

I bought a half harness from Aircraft Ignition Services in Texas.  I would give them a call to make sure you get the right harness.

  • Like 1
Link to comment
Share on other sites

  • 1 month later...

Tried to resist commenting, but can't help myself!

Last January, at annual, it was time to OH the mags and I chose NOT to go the Surefly/EIS route.  Here was my reasoning:

1) I have read multiple threads, here, and elsewhere, of various 'issues' with these electronic ignition systems, both installations and operation.

2) I have NOT had any problems with my stone-age "Tractor Mags." This is a GOOD thing!

3) Performance improvements with electronic seem marginal, at best.  Aircraft engines are stationary, and I think Lycoming did a pretty good job of optimizing timing even if it is fixed.

4) I can already operate as "deep" LOP as I care to.

5) As a career EE, I have seen far too many examples of applying new technology/complexity just because it exists.  IOW, a solution seeking a problem.

6) What was a dual, independent of external power, system now requires a power source. I'm a firm believer in the KISS concept:D 

7) Easier starting, cold and hot.  While I've scared myself with a couple of hot start situations, I've never been stranded.  And, since adopting the Don Maxwell method I've had good luck.

8) Lower overall cost due to the 2000 hour TBO.  Very true, but didn't outweigh 1 through 6 for me.

  • Like 1
Link to comment
Share on other sites

For me, the two big selling points on the SureFly are: 1 - it was time to replace both mags and my SoS, so the cost on a discounted SureFly was a wash.  2 - Lycoming is putting the same mag (w/o timing advance) on factory new engines. 

Time will tell if the claims for better LOP fuel burn are true, but even a moderate savings will add up.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.