It's the advance (firing before TDC) that gives kickbacks. This ignition has a base timing you set as a standard mag by rotating it. Actual sets at exactly TDC for starting. It then electronically advances after the engine starts and exceeds 400 rpm. This system is designed to give less chance of kickbacks than a standard mag and start better as there is no preset advance. Maybe the guys with issues never read the install manual and installed it like a standard mag and base set it at 20-22 deg when it should have been set at TDC. The more I read about this ignition, the more I like it.

Mark, thanks for the correction. A and B have different meanings. Corrected my previous. Most EI’s are set a few degrees after top dead center to ensure no possibility of kickback.

The other reason I do t really like these types of systems (electroair, pmag, lightspeed) if they have a preset map that tends towards LOP cruise operations. This can have a big effect for ROP climb, especially for airframes that are already on edge.

Either way, I have no dog in this fight. Glad to see some new products come out to replace magnetos. Just hate that these systems don’t allow users to create their own profiles to adjust for each specific installation, leaving marginal performance at times and not utilizing technology to its fullest extent.

I agree why do these these new systems have to have such limitations. Great beginning and idea. Advance while running is based on rpm and manifold pressure - perfect. But maximum advance hard set at factory based on (60 year old) engine tag, well that defeats a lot.

Timberwolf wrote:. Just hate that these systems don’t allow users to create their own profiles to adjust for each specific installation, leaving marginal performance at times and not utilizing technology to its fullest extent.

The FAA's certification process is to blame for this, not the manufacturer.

Aviation Consumer did a review of the two systems, Electroair and Surefly. They concluded that if you wanted lowest price, the reliability of electronics, and marginally better fuel economy, easy installation, go with Surefly.
Electroair will get you higher performance, much better fuel economy, better hot starts and all the other good things associated with electronic ignition. There is a reason CHT goes up with the Electroair system. You are burning fuel normally wasted by magneto ignition. You can choose to burn that fuel, higher CHT, or dial back the fuel and get the same airplane performance on less fuel.
CHT has not been an issue on my Electroair installation.

Bob

btoms wrote:Aviation Consumer did a review of the two systems, Electroair and Surefly. They concluded that if you wanted lowest price, the reliability of electronics, and marginally better fuel economy, easy installation, go with Surefly.
Electroair will get you higher performance, much better fuel economy, better hot starts and all the other good things associated with electronic ignition. There is a reason CHT goes up with the Electroair system. You are burning fuel normally wasted by magneto ignition. You can choose to burn that fuel, higher CHT, or dial back the fuel and get the same airplane performance on less fuel.
CHT has not been an issue on my Electroair installation.

Bob

IMG_4573.jpg

False, it has to do with timing. The cylinder doesn’t care where it gets the spark from, but does care when it gets it’s spark. Look at the Surefly advance schedule and you’ll see that at 2700 rpm it can advance as much as 36.5 degrees. So if you put this on a Husky and were dealing with high DA, that is way above ideal timing for best power for a takeoff. All it’s going to do is jack CHT’s way up. Combine that with slow speed and low mass flow and you’re begging to cook a cylinder.

Yikes. Three times the price and a lot of parts to mount somewhere in the cowl. Weird their site doesn't show any install pics.

I don't get it. What are you suggesting? As the pic of my Insight G4 shows running LOP and burning 12.5 GPH my CHT are certainly under control. I could get further LOP, (because of the Electroair ignition) and get even lower CHT or I could burn 13.0 GPH and get higher CHT. Higher by maybe 10/15 degrees.
I really don't know how much higher the CHT might get as I always run LOP.

Bob

btoms, I'm glad you joined into this topic. It sounds like you could go even leaner but do you figure you just slow down quite a bit so 12.5 is a nice sweet spot for speed and fuel consumption?

Bob, my underlying point is that these ignitions are a great step forward, but aren’t miracle cures. With the certified systems you are stuck with a generic conservative program that the designer thinks is best all around for most people. In the experimental world I can program my SDS for every situation and have full controllability from the dash. Once I’m in cruise I can flip a switch which advances the ignition a set amount to allow best operation when LOP.

Yes your ignition works for how you fly, but it doesn’t fit everyone.

Timberwolf wrote:Look at the Surefly advance schedule and you’ll see that at 2700 rpm it can advance as much as 36.5 degrees. So if you put this on a Husky and were dealing with high DA, that is way above ideal timing for best power for a takeoff. All it’s going to do is jack CHT’s way up. Combine that with slow speed and low mass flow and you’re begging to cook a cylinder.

I'm not super familiar with the Surefly system, but my Pmags use MAP and RPM to adjust timing. It'd be pretty irresponsible (and impossible to pass the FAA certifications) if you didn't take MAP into account.

An example:
For takeoff with an electronic ignition, you'd see a max of ~25 deg BTDC with the electronic ignition. This is because the MAP value and the RPM value would be high. Coincidentally (not really), this is the same spark advance you'd see in your magneto installation.

As MAP decreases you need more timing advance to keep peak cylinder pressures in the "sweet spot" for maximum efficiency. So if for whatever reason you were running 2700 RPM and a super low MAP, you might see as much as 36.5 deg timing advance.

If you're at a low MAP, CHTs aren't a concern since you're not producing meaningful power anyhow.

I will say that in cruise you'll see higher CHTs with an electronic ignition than you saw with magnetos, but I see no difference in WOT conditions with my Pmags than I did with my Bendix mags.

CamTom12, you are only understanding part of the equation. I disagree with your assessment that not taking MAP into account would result in not being certified. Please don’t tell magneto manufacturers that.

You’ve proven my point exactly. Not all takeoffs are with high MAP. Yes the Surefly takes MAP into account. But try taking off at Leadville in the summer. 36.5 degrees of advance is great for LOP cruising, but it is NOT where the engine needs to be to make best power ROP. Due to the power charts and standard programming in this type of system (PMag included), the timing is going to be way off the ideal setting. Which leads back to the Husky example. Way advanced timing at low speed with low cooling mass, ROP.

Timberwolf wrote:CamTom12, you are only understanding part of the equation. I disagree with your assessment that not taking MAP into account would result in not being certified. Please don’t tell magneto manufacturers that.

I meant specifically for electronic ignitions and timing advance maps.

Timberwolf wrote:You’ve proven my point exactly. Not all takeoffs are with high MAP. Yes the Surefly takes MAP into account. But try taking off at Leadville in the summer. 36.5 degrees of advance is great for LOP cruising, but it is NOT where the engine needs to be to make best power ROP. Due to the power charts and standard programming in this type of system (PMag included), the timing is going to be way off the ideal setting. Which leads back to the Husky example. Way advanced timing at low speed with low cooling mass, ROP.

That’s a fair point- I’ve never been to Leadville.

Sounds like for someone wanting to do that specifically, they should just keep their mags.

Given your RV background, this is probably the Husky example you’re talking about, right?


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Absolutely. Gotcha on the EI specific. Makes sense.

In the grand scheme, people need to understand the operating principles behind these devices and though the manufacturer gives a WAG to accompany most scenarios, it doesn't fit everyone. Additionally these devices require power to function and a thorough analysis should be completed prior to deciding this is right for their aircraft. A step in the right direction, but still very constrained for the certified crowd.

Timberwolf wrote:Absolutely. Gotcha on the EI specific. Makes sense.

In the grand scheme, people need to understand the operating principles behind these devices and though the manufacturer gives a WAG to accompany most scenarios, it doesn't fit everyone. Additionally these devices require power to function and a thorough analysis should be completed prior to deciding this is right for their aircraft. A step in the right direction, but still very constrained for the certified crowd.

Yup, we’re in violent agreement. Sorry for the misread earlier!

180Marty wrote:btoms, I'm glad you joined into this topic. It sounds like you could go even leaner but do you figure you just slow down quite a bit so 12.5 is a nice sweet spot for speed and fuel consumption?

I can get my fuel flow down into the low 11GPH range since the Electroair Electroni Ignition install.
I don't really push it though. Most of my flying is at 3K' over the shores of Lake Michigan and I'm not comfortable when the engine 'hiccups' while over the water.
I would estimate the Electroair system at the 23 square 3K' setting would save me about .5 to .6 gph if I chose to go that far LOP. At higher altitudes the fuel savings get much better approaching 2gph.
Attached is another G4 pic showing 23 squared at 11.4 fuel flow.

Bob

btoms wrote:

180Marty wrote:btoms, I'm glad you joined into this topic. It sounds like you could go even leaner but do you figure you just slow down quite a bit so 12.5 is a nice sweet spot for speed and fuel consumption?

I can get my fuel flow down into the low 11GPH range since the Electroair Electroni Ignition install.
I don't really push it though. Most of my flying is at 3K' over the shores of Lake Michigan and I'm not comfortable when the engine 'hiccups' while over the water.
I would estimate the Electroair system at the 23 square 3K' setting would save me about .5 to .6 gph if I chose to go that far LOP. At higher altitudes the fuel savings get much better approaching 2gph.
Attached is another G4 pic showing 23 squared at 11.4 fuel flow.

Bob

IMG_2314.jpg

What plane engine are you running?

O-470-50 PPonk

Bob

btoms wrote:O-470-50 PPonk

Bob

IMG_0886 (1).jpg

Interesting. We have no problem getting our pponk down to 9.5GPH at 6500ft on the 182. Had it down at 8.7 at 8500 and it was still running real nice. No significant speed loss, we were still trued out at 120kts which is book speed. Be interesting to see how it would improve with electronic ignition.

I am a low level guy. Don't think I have ever had this airplane to 6500'.
What are your MP and RPM settings at 6500' to get 120kts?
I have not played with different altitudes and engine settings. I pretty much always fly at 23 squared and between 2500' and 3000'. I usually shoot for fuel flow between 12 to 12.5 GPH.
I just had the Sportsman Stol installed and surprisingly picked up 4-5 kts, 140kts IAS. The original Cessna camber cuff did have some dents.
Attached is pic of my last flight, after the Sportsman install.

Bob





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