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  #51  
Old 05-18-2015, 07:13 AM
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Originally Posted by rocketman1988 View Post
Now, a "new" (not really) tech comes along, that has the potential to makes things better. What do you know? It is crazy nonsense again...at least until it becomes the new status quo.
Electronic fuel injection is certainly not crazy nonsense. In many ways it is better than a mechanical system, and in a few ways worse. I think readers desire an honest discussion of fact, regardless of their personal choice, as they prefer to know the truth about both the better and the worse.
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  #52  
Old 05-18-2015, 07:30 AM
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Originally Posted by DanH View Post
Electronic fuel injection is certainly not crazy nonsense. In many ways it is better than a mechanical system, and in a few ways worse. I think readers desire an honest discussion of fact, regardless of their personal choice, as they prefer to know the truth about both the better and the worse.
It is better. The question is, is it worth the cost?

Magnetos are indeed very old technology but they work, not perfectly, but they work.

My take on it is when the first mag fails, it will be replaced with EI. I would have done it already if I could have sold a new mag at 2/3's its cost, but their were no takers so I did not do it.

To convert to EFI with a Lycoming is a big deal, just not sure it is worth it. EI is easy and its benefit is apparent and obvious from the git-go. How much better EFI is beyond EI is subjective and matter of personal choice.

My take on Rober Paisley is all positive, he is a stand up guy and if you go with his EFI system, it will be ok. If my money bucket was over flowing I would do it just for the kicks.
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  #53  
Old 05-18-2015, 07:33 AM
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Originally Posted by DanH View Post
Electronic fuel injection is certainly not crazy nonsense. In many ways it is better than a mechanical system, and in a few ways worse. I think readers desire an honest discussion of fact, regardless of their personal choice, as they prefer to know the truth about both the better and the worse.
We know that. But a lot of people in the light GA segment see anything as crazy nonsense if it's not decades-old practice. It's like I said elsewhere, if a practice or method goes long enough without advancement or changes, it seems to ossify into "it's been done this way so long that it must be the best way it could ever possibly be done", and anything not that way is Inconceivable!

That's certainly not to say every new thing must be adopted hastily and completely; the proper testing and design work must still be properly accomplished. But it also shouldn't be automatically dismissed just because it's not the "traditional" way of doing things.

"There are two kinds of fool in the world. The first says 'this is old, and therefore good'; the second says 'this is new, and therefore better'".



Quote:
Originally Posted by David-aviator View Post
It is better. The question is, is it worth the cost?

Magnetos are indeed very old technology but they work, not perfectly, but they work.

My take on it is when the first mag fails, it will be replaced with EI. I would have done it already if I could have sold a new mag at 2/3's its cost, but their were no takers so I did not do it.

To convert to EFI with a Lycoming is a big deal, just not sure it is worth it. EI is easy and its benefit is apparent and obvious from the git-go. How much better EFI is beyond EI is subjective and matter of personal choice.

My take on Rober Paisley is all positive, he is a stand up guy and if you go with his EFI system, it will be ok. If my money bucket was over flowing I would do it just for the kicks.
To me, EFII is worth it, despite the upfront complexity, because of the operational simplicity and the efficiency. The idea of not having to fiddle with a mixture knob every time I change the power is very appealing, and the system architecture addresses the majority of the occasional issues with running mogas/E10, or even fuel injection, with a fuel system that wasn't originally designed for it. I don't mind spending a little more time, money, and effort up front if it saves me those things later. Unless something changes between now and engine-buying time, I'm going with EFII.
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Last edited by rmartingt : 05-18-2015 at 07:41 AM.
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  #54  
Old 05-18-2015, 07:43 AM
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Originally Posted by DanH View Post
Electronic fuel injection is certainly not crazy nonsense. In many ways it is better than a mechanical system, and in a few ways worse. I think readers desire an honest discussion of fact, regardless of their personal choice, as they prefer to know the truth about both the better and the worse.
Yes, I appreciate the discussion on this. I'm learning a lot (or at least seeing things that make me do more research).

Mods, I think this thread might be more appropriate for one of the engine-related subsections, since it's not just RV-10 specific. Would it be possible to move it?
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  #55  
Old 05-18-2015, 09:20 AM
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I like to see the feedback here from users and those considering EFI. Obviously here are many reasons why someone might choose to use it, whether or not it provides any useful performance or fuel economy gains even.

Interested to hear any more ideas and comments.
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  #56  
Old 05-18-2015, 01:54 PM
David-aviator David-aviator is offline
 
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I would be concerned about the Lycoming intake manifold.
Is it optimized for EFI? Probably not.
Another issue is 100LL and the O2 sensors.
I would be happy with EI but not sure EFI and Lycoming are good partners.
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  #57  
Old 05-18-2015, 04:15 PM
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Quote:
The idea of not having to fiddle with a mixture knob every time I change the power is very appealing
If that is a problem to you then you are doing it wrong. Let me explain by way of example. Recent flight doing an Instrument renewal. 6 Mixture functions in all and i barely recall doing them. I select radio and nav functions more often in a flight and they are far more complex. Programming the flight plan in a GTN is more involved.

1. Prime/Start > Mixture never got past half way then leaned back to see the RPM rise.
2. Mag check done aggressively lean as possible
3. Full rich for takeoff
4. Lean to target EGT in the climb at 3500-4000'
5. Big Mixture pull levelled out at 6000' and appropriately LOP. Simple as that.
6. Idle Cut Off at the hangar door an hour and a half later.

In that time the plane did an ILS with a hold, VOR-DME arc app, RNAV app, and all the climbs and repositions and missed approaches, plus unusual attitude recovery checks, all using nothing but throttle. The FCU took care of everything.

Unfortunately over time pilots have been taught by instructors who knew no better, and just made simple things very complicated and scary for the pilot, because the instructors were scared themselves by old wives tales.
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  #58  
Old 05-18-2015, 05:19 PM
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Originally Posted by Bill Dicus View Post
Dan - Thanks for that exposition. My -8 is at 32 hours. Cruise CHT's within 9 or 10 degrees (320-330) on Lycon IO360M1B with 10:1 compression. EGT's vary more, with 1 and 4 being higher (1229,1180,1149,1241). All @ slightly below peak EGT, OAT 55F - the pattern holds @ widely different speeds and mixtures. Seems time to perform GAMI lean test and consider swapping/changing injectors. Would you do anything else first? Please pitch in, everyone. Thanks.
Sorry Bill, I think you got run over in the stampede. Let's look at what you have...

First, is this an EFII electronic fuel injection, a mechanical fuel injection, or a carb?

Second, are you "All @ slightly below peak EGT" on the rich side or the lean side?
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  #59  
Old 05-18-2015, 05:31 PM
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Originally Posted by rv6ejguy View Post
OTS injectors are usually flow matched to about 2-3% variance. Along with this, each port flows slightly different amounts of air so this results in the same issues as with mechanical injectors hence the GAMI idea is needed to correct AFRs for individual cylinder.
Quote:
Originally Posted by rcpaisley View Post
GAMI spread information is not applicable to electronic injection - you already have balanced fuel delivery.
Quote:
Originally Posted by rv6ejguy View Post
I mentioned in a previous post about the GAMI spread being essentially the same as with mechanical injection using standard nozzles. That's a reality.
Quote:
Originally Posted by rcpaisley View Post
As previously noted, the GAMI test is really irrelevant to electronic injection, you already have the fuel balance goal achieved.
You guys should really talk more often
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  #60  
Old 05-18-2015, 07:52 PM
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(warning, beer-fueled rant to follow)

Quote:
Originally Posted by RV10inOz View Post
If that is a problem to you then you are doing it wrong. Let me explain by way of example.
Whether it's "easy" or "simple" or not shouldn't matter--I shouldn't have to do it in the first place. None of the cars I have ever driven, not even the oldest ones that were about my age, have required me to pay any attention to fuel-air mixture or any other parameter unless something was wrong. I've driven cars over nearly as wide a range of altitudes as any airplane I've flown, with constantly varying throttle settings, and never once had to give the slightest thought to fuel-air ratio. And all of these are cars that, brand new, still cost less than just the engine that I'm putting in my airplane.

There's no reason an airplane engine should be any different--and in many airplanes, it isn't; turbines don't come with mixture knobs, even the ones with all-mechanical engine controls. I want to get in and fly, not babysit an engine, and not play flight engineer. And since we don't have to worry about all the complicated emissions reduction stuff that cars and trucks do, it makes the control issue simpler. Simply program the controller to provide the lowest possible fuel burn for a given power setting while keeping temperatures within normal limits and not causing damage to the engine. As long as I'm not damaging the engine or causing a temperature issue, why would I ever want to burn more fuel? This is the kind of thing that automated controls are made for, and they do a lot better job of it than humans do once properly set up.

Besides, what advantage is gained from full-time manual mixture control? "Simplicity" is often claimed, but there's more than one way to look at simplicity--and operational simplicity, while sometimes ignored, counts just as much. What problem does it solve? What advantage does it gain me to be fiddling with something else in the cockpit right at the times when my workload is likely to be higher, like right after takeoff or in the pattern or in maneuvering flight with lots of power changes? To me, it seems like this level of manual control has a lot more potential for pilots to introduce problems that otherwise wouldn't exist (how many engines are driven to early overhaul, or fail in flight, due to improper mixture management? How many thousands of gallons of fuel get burned needlessly because pilots don't want to, don't know how to, or for some reason can't run at an optimum LOP condition? and for that matter, how many airplanes get totaled every year due to carb ice, which could have been obviated by not having a carb in the first place?) than it does to save a pilot from something they otherwise wouldn't catch. Yes, there are failure modes that might require pilot intervention to save the engine, but for those instances an override can be provided, and requiring full-time manual mixture control under all other conditions isn't going to make that problem any less likely.

The mixture knob, like the vacuum gyro, looks like another one of those solutions that was developed a long time ago (100+ years, in this case) because there just wasn't any better way of doing it at the time, and there continued to be no better way of doing it (or at least, no affordable way of doing so) for a few decades, up to and past the "golden age" of the light airplane. It's become one of those things that we have just accepted as normal despite being incredibly anachronistic, just because 90% or so of the light airplane fleet was built before any other feasible means of doing it was available. That still doesn't make it the "best" way to do it.

We in the light GA segment like to gripe about being stuck flying behind 1930's technology in our engines--but then if anyone suggests actually doing something about it, we gripe about that. IMHO, after modern glass EFII-like systems appear to represent the biggest bang-for-the-buck improvement in real-world operational efficiency and simplification that we're going to see for light airplanes, especially if we constrain it to things that can be relatively easily retrofitted to existing airframes.

I don't think it's too much to ask that my brand-new airplane be caught up technologically with 1980s automobiles, especially when you consider that the technology I'm going to be putting into the panel is quite recent, and has features that were bleeding edge, still-in-R&D level when I started my career testing integrated avionics packages for high-end jets.


Quote:
Unfortunately over time pilots have been taught by instructors who knew no better, and just made simple things very complicated and scary for the pilot, because the instructors were scared themselves by old wives tales.
I wasn't taught to lean by my instructors, because in the tired old underpowered C150 I trained in, the throttle went to full rental power at takeoff and it didn't move again until you pulled the power on downwind, and the hourly charge was the same whether I leaned or not. The mixture knob was simply used to shut the engine off at the end of the flight.

That same old 150--the good one at the flight school, because it had a text-only GPS and was in marginally better shape than the other one--met its end between a pair of trees six weeks after I flew it for my checkride when that "simple" carburetor iced up and both the CFI and student forgot the carb heat. A perfectly good airplane ruined because of a simple oversight regarding a manual engine control.
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