The International Cessna^® 170 Association

Has any body had any experience with the solid state mag SUREFLY . I can hear the rumblings all ready saying this a constant speed engine [4 cylinders type ] normally . But my response is I run a fixed pitch prop and my RPM is viable while my engine is at 25deg before TDC all the time [except starting ] so maybe advancement could help . They retard themselves on starting . I am asking before purchasing . Is there any fuel saving ? Or smoother running?

How is it that Surefly has the STC to install a SIM (Surefly Ignition Module) on the C-170 yet apparently doesn’t yet have the unit certified? One can only buy a “pre-certification unit” now for $1550.

A buddy installed one on his C206 and claims he likes it now.

He had a weak battery to start with and when he tried to start the engine, battery voltage dropped below 9 volts, if I remember correctly, and the unit dropped offline. Now he has a good battery and it works ok.

n2582d wrote:How is it that Surefly has the STC to install a SIM (Surefly Ignition Module) on the C-170 yet apparently doesn’t yet have the unit certified? One can only buy a “pre-certification unit” now for $1550.

They kind of explain that here.

I guess I'm just slow to understand. Everything else on their website gives me the impression the ignition module is certified. Maybe they just haven't updated this page which refers to "pre-certification units".

I not sure what they are saying either but it seems before certification you installed them using an STC and afterward they are considered certified replacements. Maybe those mags produced prior to be certification are not considered certified and MUST be installed using an STC???

They required an engine STC and an airframe STC. So the units have passed certification under FAR 33 rules and that's why SureFly can say its certified. They're having some troubles getting the full features of the EIS with the AML STC. If anyone wants more info you can email me personally.

jrupert@lycoming.com

-Jud

Electroair here in Howell Michigan also has an electronic ignition certified for the O-300. But, at about 5.5 AMUs (before installation), it would take over a thousand hours to pay for itself, even if it saves as much as 1gph running $5 avgas. I’m not at all certain I have that much flying left in me. My Dad was probably right when he said fuel is one of the cheapest things you can put in an airplane.

cessna170bdriver wrote:Electroair here in Howell Michigan also has an electronic ignition certified for the O-300. But, at about 5.5 AMUs (before installation), it would take over a thousand hours to pay for itself, even if it saves as much as 1gph running $5 avgas. I’m not at all certain I have that much flying left in me. My Dad was probably right when he said fuel is one of the cheapest things you can put in an airplane.

I may have paid for mine, have run an Electroair on my RV-7 for 14 years and 1200 mostly trouble free hours (had to replace the pickup probe) runs very smooth. Use REM37BY plugs in order to gap to .35 .

Just curious how efficient the variable timing feature is when the mechanical mag will always be firing using fixed timing? (I realize that feature is not approved yet)

the variable timing unit will be firing first when advanced, so its like you're running a single ignition and the regular mag will be there as a wasted spark.

With a two degree difference in spark advance between our left and right Bendix mags is the right magneto just along for the ride?

n2582d wrote:With a two degree difference in spark advance between our left and right Bendix mags is the right magneto just along for the ride?

I would say no, since, even in cruise, you get a slight power drop when switching to either mag.

Good point.

Two spark plugs modify the flame propagation pattern and insure the air/fuel mixture is completely consumed. If you have an EGT gauge, if you switch to one mag, you'll observe an INCREASE in EGT because a portion of the combustion is occurring so late (as the gases exit the cylinder.)