diamondaviators.net

Rich: Very interesting. Those inline fuse holders for buss fuses have been in use forever in the automotive application without issues. Of course, very short transients would be more likely to affect a timed electronic system like the SureFly as opposed to the mostly analog electronic systems of my vintage. I actually have one of those fuse holders installed in my DA40, in the BatteryMinder harness. No problems, but that system is used only on the ground, with no vibration from a running engine. I did take care to secure the holder to a big cable harness with multiple Zip ties, though.

Was your fuse holder secured well to minimize the possibility of vibration-induced wire flexing? (Knowing you via this forum for many years I would assume that it was...)

Steve

Steve wrote: ↑Sat Jan 11, 2020 2:37 am Was your fuse holder secured well to minimize the possibility of vibration-induced wire flexing? (Knowing you via this forum for many years I would assume that it was...)

Steve

It is secured to a convenient wire bundle, as is the power lead itself. As you know, a certain amount of vibration permeates pretty much everywhere in the plane. I have even wondered about the natural frequency of the spring. Both I and my usual mechanic are really big on proper electrical component security. We sometimes stand around and shake our heads at some of the planes that come into his shop.

Inline glass fuses are pretty much non-existent for built-in systems in newer cars and even motorcycles, in favor of the blade types.

A couple of other things:

1. A minor restriction is now added: One must use 100 LL. It's minor because the DA40 is already so restricted and that's the only fuel around airports anyway. But the IO-360-M1A itself is not so restricted, It is a 91/96 min octane. I suspect some of the other aircraft on the list might even have 80/87 engines and have that weird Petersen STC for autogas.

2. Another placard is to be added regarding the engine having a battery-powered ignition component, with an admonition not to take off with a depleted battery. The placard is about 1"x3.5". I have to figure out where to put it, though there is some blank panel space available. It occurs to me space could be a problem in G1000 panels.

Rich - just curious if you have any additional Pireps on surefly?

Starting, power, efficiency, speed, smoothness...

Thanks!

briankelly327 wrote: ↑Wed Jan 22, 2020 3:37 pm Rich - just curious if you have any additional Pireps on surefly?

Starting, power, efficiency, speed, smoothness...

Thanks!

Still working on gathering data. Some things I can say:

Starting - great. But I had no problems to begin with, using the SS.

Power - Maybe a bit of an increase, maybe not. It would show up in rate of climb most obviously, but I don't have detailed baseline numbers, since climb rate is so good. A data point: It's sort of cold right now and flying somewhat light (2200 lb.) the other day, through 4-5K ft. DA I was at 1200 FPM.

Speed - Seems the same. More research needed. It takes a lot of power change to affect speed - more so than climb.

Smooth - subjective, but seems smoother. (Disclaimer: Could be cow-magnet effect)

EGT's definitely down Peak EGT happens barely over 1500 deg, at altitudes where they used to peak at 1525-1530.

I've now got a problem with #3 CHT that may or may not have been caused by the SF itself. I found an anomaly (several, really) with the #3 cooling baffle and airflow that might have been exacerbated by the activities related to the installation of the SF. #3 has long been the highest CHT by a bit and I am going to tackle this part of the equation as a whole. Expect a separate thread on the weirdness after I settle on the details/remedy.

No 3 CHT solved. I believe it was due to the SCAT tubing that runs to the base of the battery mount having somehow migrated where it was wedged underneath the #3 cylinder head, placing it in a position to impede airflow across the cooling fins in that area. This area is exactly where the CHT sensor sits, possibly giving a misleadingly high representation of that cylinder's head temperature. I corrected this routing problem and did a couple of other tweaks to pre-existing things. Separate thread coming on all this.

Things back to normal, now. #3 still highest, but in normal range rather than bumping up against 400 deg.

Update:

1. The unit does not come with a boot to cover the hot terminal. It needs one. While doin' stuff in the engine compartment, such as with an inspection mirror, it's easy to short it and blow the fuse.
2. Carry extra fuses.

That is all.

More bits and pieces:

I still don't have definitive in-flight numbers, as I haven't found the time or conditions to go through the exercise, but for sure the plane starts quicker (and it wasn't a problem before) and also starts smoother. That is, I don't get that sometimes blup, blup, blup, vroom happening after the engine catches.

Subjectively, I perceive the engine runs smoother. That's my story and I'm sticking to it.

CHT's seem to be strangely insensitive to fuel flow/EGT changes. I need to better quantify.

Recommended maintenance practice based on theoretical notions: When doing work in the engine prop area, consider removing the fuse from the fuse holder and re-closing it, maybe with a blown fuse inserted inside. (I happen to have one of those ). This disables the unit entirely, ensuring that it can't fire the engine when not desired. Be sure to put the good fuse back in, of course.

Corollary: If, like I did, you replace the left mag with this unit and you're concerned about someone stealing the plane, just remove the fuse. The engine absolutely will not start at all.

Rich, Brian, Steven - Are you still happy with your Surefly ignitions? My right mag has gone bad (after less than 200 hours) so I'm considering adding a Surefly. Like Rich I have the VM1000 so as I understand it I have to switch the RPM sensor from the right to the left mag.

Rich, I know you ended up NOT doing this but did you see any issues with doing so when you did your left mag replacement? Also, did you sort out the lack of changes to the CHT? My #1 runs hot so I don't want lose the ability to cool it. On the other hand if the Surefly contributes to cooling I'm definitely in.

Thanks. Bernie

blsewardjr wrote: ↑Mon Mar 23, 2020 4:39 pm Rich, Brian, Steven - Are you still happy with your Surefly ignitions? My right mag has gone bad (after less than 200 hours) so I'm considering adding a Surefly. Like Rich I have the VM1000 so as I understand it I have to switch the RPM sensor from the right to the left mag.

Rich, I know you ended up NOT doing this but did you see any issues with doing so when you did your left mag replacement? Also, did you sort out the lack of changes to the CHT? My #1 runs hot so I don't want lose the ability to cool it. On the other hand if the Surefly contributes to cooling I'm definitely in.

Thanks. Bernie

Inconclusive on the CHT's. I haven't messed with this factor since I don't seem to have any real CHT problems now. As far as the left vs. right mag, it just looked a bit simpler to replace the left mag. Routing of the RPM sensor wiring and reaching below the left mag to install it looked like more hassle than it was worth, given both mags were working. In your case, it'd be worth the trouble and I know others have done it.

Just be sure the fuse mounts securely in its holder. In fact, I'd recommend using a flat automotive fuse/holder, instead of the one they supply. I also recommend using a terminal cover over the power terminal.