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-   -   Exciting Skytec electric mag (https://vansairforce.net/community/showthread.php?t=140258)

ReidVaitor 08-26-2016 10:37 AM

surefly
 
Quote:

Originally Posted by tim2542 (Post 1098268)
Not much info on the web page, practically none except a coupe of videos of a plane running and flying on one. .
Tim Andres

Site has been updated with much better information.

Lenny Iszak 08-26-2016 11:00 AM

Nice, they just published the advance curve. Wonder how this compares to Lightspeed's curve.
Interesting that you only get full 38 degree advance at 2700rpm.

Lenny

DanH 08-26-2016 02:57 PM

Quote:

Originally Posted by Lenny Iszak (Post 1106759)
Nice, they just published the advance curve. Wonder how this compares to Lightspeed's curve.
Interesting that you only get full 38 degree advance at 2700rpm. Lenny

Only?

This is much more aggressive than Lightspeed. At 2600~2700, a LS won't reach 38 degrees until MP is down to 13". If I read the Surefly illustration correctly, it reaches 38 degrees at 21".

The Surefly map is even more aggressive than an Electroair map.

At high manifold pressure, 25 to 30 degrees was the ballpark for max HP in the only hot-rodded Lycoming "timing vs HP" study I've seen in print.

Might work ok LOP, but it's probably too advanced for ROP operation, in particular near stoich. I suspect it will just raise CHT without going faster.

That's the beauty of the dual map switch on the new SDS ignition, or a homebuilt EDIS....two maps, one for ROP, one for LOP.

In the company blog, Rich says what they heard a lot at OSH was "I just want to get rid of my mags." If I were the Surefly guys, I'd think hard about doing just that...sell a certified EI mag replacement with fixed timing. Sound crazy? Consider...the average schmoo with a Cherokee or a 172 is carbureted, so he has lousy mixture distribution, and can't run LOP with smoothness. He may not run LOP much even if distribution was great; too many scary stories from the local airport peanut gallery. He doesn't fly high either. Those customers would love the easy starting and automotive plugs, but fixed timing wouldn't have a chance of creating a cooling problem. Most of those span cans have awful baffling.

FasGlas 08-26-2016 03:21 PM

Well, it certainly leaves a lot to be desired. I need more info before I can judge this new contender. If it's simply a plug and play alternative with no real spark energy increase or duration than, dare I say, a pmag.... I think the pmag has more versatility not to mention the built in power source. The Skytec has no power source, no data ports, no way to alter timing (other than changing the physical setting). As much as I can't stand pmags this doesn't look like a better alternative. IMHO, if you're gonna install an EI, install a good one that you can tailor to your aircraft and needs. This EI looks like something they are looking to replace magnetos in certified planes. ElectroAir is also producing an electronic magneto for certified planes.

To Dan: The ElectroAir (Jeff Rose) will advance as much as 40 degrees total, less aggressive on the curve but more total advance. In my experience this curve keeps the CHT's more at check and still gives a very good performance increase. Adding to this the high energy and long duration spark.

DanH 08-26-2016 03:59 PM

Quote:

Originally Posted by FasGlas (Post 1106834)
To Dan: The ElectroAir (Jeff Rose) will advance as much as 40 degrees total, less aggressive on the curve but more total advance. In my experience this curve keeps the CHT's more at check and still gives a very good performance increase. Adding to this the high energy and long duration spark.

Sorry, I wasn't terribly clear. By "more aggressive than an Electroair" I mean the Surefly has advanced to 38 degrees at 21 inches, while the latest published Electroair map is 32 degrees (base plus 7) at 21 inches. Electroair's 40 degrees (base plus 15) isn't until MP falls to 17 inches.

Hey, wait, that's what you mean by "less aggressive on the curve" ;)

Lenny Iszak 08-26-2016 04:09 PM

Dan, I was under the impression that the Lightspeed goes to 42 degrees. Had no idea that it's never remotely close to that at 2390 rpm where I cruise LOP.

Lenny

Quote:

Originally Posted by DanH (Post 1106827)
Only?

This is much more aggressive than Lightspeed. At 2600~2700, a LS won't reach 38 degrees until MP is down to 13". If I read the Surefly illustration correctly, it reaches 38 degrees at 21".


DanH 08-26-2016 04:50 PM

Quote:

Originally Posted by Lenny Iszak (Post 1106851)
Dan, I was under the impression that the Lightspeed goes to 42 degrees. Had no idea that it's never remotely close to that at 2390 rpm where I cruise LOP.Lenny

It may have the capability, but it doesn't seem to do so when operating correctly, not according to the engine monitor download I'm looking at. In the 2350~2400 range, max advance appears to be 38.6 at 12" MP.

That said, forget about maximum advance in absolute terms. The real issue is "What advance at what manifold pressure?. There is a world of difference between 38 at 21" (Surefly), and the 38~40 at 13" or less we see with the others.

FasGlas 08-26-2016 06:18 PM

Quote:

Originally Posted by DanH (Post 1106865)
It may have the capability, but it doesn't seem to do so when operating correctly, not according to the engine monitor download I'm looking at. In the 2350~2400 range, max advance appears to be 38.6 at 12" MP.

That said, forget about maximum advance in absolute terms. The real issue is "What advance at what manifold pressure?. There is a world of difference between 38 at 21" (Surefly), and the 38~40 at 13" or less we see with the others.

Dan, you are 100% correct. Too much advance to early can cause high CHT's and possible detonation. I prefer the slower advance curve and the higher max advance at the top. Without bringing up how efficiently the spark is burning the fuel.

Toobuilder 08-26-2016 06:50 PM

Quote:

Originally Posted by DanH (Post 1106827)
Only?

This is much more aggressive than Lightspeed. At 2600~2700, a LS won't reach 38 degrees until MP is down to 13". If I read the Surefly illustration correctly, it reaches 38 degrees at 21"...


Agree. That is a BUNCH of advance based upon my testing. Flew a nice long cross country to PHX last night and 22 inches/2300 RPM was my usual 30 degrees (rich). Even as much as 50LOP, 33 is about optimum at that power setting. 38 degrees might work at extremely high altitude or so lean that it would be comical. 38 degrees would be nuts with my stock 540 and a "normal" power setting.


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