[Webb]

Here's a business ideal for someone. If you do it and are successful, just send me a box of Cuban cigars and one of the units and I'll be a rich man just knowing an ideal worked while I enjoy a good cigar.

Here Goes............................

With all the discussion about LOP going on and doing it right, why not develop a computer controlled mixture adjustment servo. It would be active instead of passive, easy to override/turn off and would turn off as soon as you touched the mixture control.

For lack of a better name, call it the MAP (Mixture Auto Pilot).

Here's how it would work..........

The vernier cable would be interrupted with a servo in the middle. The pilot wouldn't notice anything unusual in the cockpit. Just a normal red knob and and the panel unit. The servo just turns the cable.

The plane would need to be flow matched to enable the LOP function.

Using data from the plane's instruments, it auto sets the mixture. When at altitude, you push the LOP button and the unit will go into LOP function. The LOP function won't engage until at or below 60% power. As soon as hits 61%, the unit goes to ROP or even richer depending on altitude and power.

The stuff that we dream up........

 

[Don at Airflow]

Auto mixture

That's already being worked on.

Don

 

[Geico266]

That's already being worked on.

Don

It's already been done. Rotax uses pressure compensating carbs on their 4 strokers. The only engine control is the throttle, and "choke".

Don, good to hear from you, are you doing any semiars at OSH? I need a refresher.

 

[L.Adamson]

I confess..........

I kind of like the mixture control! I grew up flying in high altitude mountain country, which required use of mixture from day one.

With moving map GPS's taking away the fun of whiz wheels and VOR plotting; the red knob gives me something to do!

L.Adamson --- RV6A (flying)

 

[frankh]

It's already been done. Rotax uses pressure compensating carbs on their 4 strokers. The only engine control is the throttle, and "choke".

Don, good to hear from you, are you doing any semiars at OSH? I need a refresher.

The Bing carb does not have mixture control like Webb was suggesting. It simply adjusts mixture based on altitude..In other words it sits roughly at the same ROP position regardless of altitude. I.e it does not swap to LOP at will.

What Webb is taling about is done but the electronic ignition system..the name of which escapes me right now.

Frank

 

[Jconard]

A lot of work to add to an engine that spends 95% of its time (on a flight suitable for LOP..cross country) at one speed, and one power setting.

Seriously, what if we invented an operator...who would have "servo controllers" long enough to reach the panel and flight controls.

We could train this thing we call "operator" to interpret data, and follow rules and practices. This operator could learn from past experience and integrate years of related aviation experience and book knowledge into the rules.

We could make this operator directly responsible for the cost of repairs, and failure of the airplane, so that the operator had reason to learn and follow the rules.

We could try to instill in this operator a sense of accomplishment based solely on completing a flight properly and performing each task in the flight correctly. We might name this subroutine "pride"

If we were able to create such an intelligent, multi routine capable operator unit, which was constatly learning from each flight and from the flights and research of other operators, and applying its learning to successive flights in an effort to correctly complete each flight we may even have a whole new thing.

We might then call such a thing....a PILOT.

 

[Don at Airflow]

FI 101 Class

It's already been done. Rotax uses pressure compensating carbs on their 4 strokers. The only engine control is the throttle, and "choke".

Don, good to hear from you, are you doing any semiars at OSH? I need a refresher.

Larry,

We will not be at Oshkosh this year. I?m trying to figure out how to attend (find an affordable flight and lodging) the Reno Air Races this year. As for fuel injection seminars, our last FI 101 class is the first weekend in November (Nov. 7-9). There are still some openings for that class. The next class will be in March 2010 (date not firm yet).

Don

 

[frankh]

No way!

A lot of work to add to an engine that spends 95% of its time (on a flight suitable for LOP..cross country) at one speed, and one power setting.

Seriously, what if we invented an operator...who would have "servo controllers" long enough to reach the panel and flight controls.

We could train this thing we call "operator" to interpret data, and follow rules and practices. This operator could learn from past experience and integrate years of related aviation experience and book knowledge into the rules.

We could make this operator directly responsible for the cost of repairs, and failure of the airplane, so that the operator had reason to learn and follow the rules.

We could try to instill in this operator a sense of accomplishment based solely on completing a flight properly and performing each task in the flight correctly. We might name this subroutine "pride"

If we were able to create such an intelligent, multi routine capable operator unit, which was constatly learning from each flight and from the flights and research of other operators, and applying its learning to successive flights in an effort to correctly complete each flight we may even have a whole new thing.

We might then call such a thing....a PILOT.

It simply cannot be done..I mean think about it..Your idea means we would have to train CFI's and then (swallows hard) the CFI's would have to train student pilots to actually use the mixture control!

Its just asking way too much in my opinion..

Mind you there is plenty of training around mixture control.."Hey whats this for?..Oh that shuts the engine down!"

Frank

 

[Geico266]

The Bing carb does not have mixture control like Webb was suggesting. It simply adjusts mixture based on altitude..In other words it sits roughly at the same ROP position regardless of altitude. I.e it does not swap to LOP at will.

What Webb is taling about is done but the electronic ignition system..the name of which escapes me right now.

Frank

Frank! Work with me here!

Take the (very reliable) pressure sensing device (system theory) from the Bing carb, install Web's electronic LOP servo gizmo (very scientific terminology) that is connected to EGT, ALT, ect. sensors and not only do you have a system that runs the correct ROP setting for take off's and landings (no more sputtering in the mountains full rich) and fail safe mechanical mode, you have an electronic system capable of LOP during cruise.

I wan't trying to rain on Web's parade, I was trying to join it.

 

[nucleus]

I have seen this implemented

in a turbo RV-6, there were two button on the stick, one for climb and one for cruise, a little chip and two servos to control mixture and wastegate. I don't know who ended up with that plane, but it was sold by the original builder.

Hans

 

[Webb]

It simply cannot be done..I mean think about it..Your idea means we would have to train CFI's and then (swallows hard) the CFI's would have to train student pilots to actually use the mixture control!

Its just asking way too much in my opinion..

Mind you there is plenty of training around mixture control.."Hey whats this for?..Oh that shuts the engine down!"

Frank

Yeah yeah, and the world is flat Christopher Columbus.

Frank, come on....folks train in planes with auto-pilots and learn to fly them......All I'm talking about is a auto pilot for the mixutre if we choose to engage it......

John - The point is not to dimenish pilot skills but to augment them by using a computer that can accurately monitor and adjust a fuel mixture constantly for the best use of our resources...ie fossil fuels. The car industry has been requiring this for years. Proactive response on our side might just ensure fuel is available for something that we do that most others do not consider an essential need.

Based on the above satirical view, I would have to assume you are still driving a Model-T and have to manually advance the spark and adjust the mixture for the engine to run best. This must mean that you are a driver.

Please view the poke as a good natured jest...I do understand your point and just having a bit of fun.

Larry - I think you have the correct ideal. We have such advances these days in things that have shown up in the cockpit. GPS, EMS, Forward Vision, glass panels which augment, not detract from our skills.

Yes the world is flat, and we are using engines that have been essentially unchanged for decades. I'm not suggesting changing the raw design. Just the way we feed it for the best use of resources. Mother Earth wins, our wallets win, and our engines win.

Can't never did. So far I haven't heard a sound reason why it couldn't happen. I'm not even talking about putting additional sensors in the engine.
We already have the info from current engine sensors. A simple computerized mixture auto contol driving a servo.

I sure hope I don't fly off the edge of the world one day......

 

[rvmills]

FADEC?

Webb,

What you are describing sounds a bit like a FADEC (Full Authority Digital Engine Control). Here are a couple links found with a Google Search on "FADEC" (some interesting reading).

Wikepedia article: http://en.wikipedia.org/wiki/FADEC
Avweb article (c1998): http://www.avweb.com/news/newacft/182749-1.html

Mooney tried the concept with the Porche Mooney PFM, but only sold 41 of them ($60,000 upgrade back then). The Avweb article said that Lycoming and Continental were working on FADEC technology back then (1998), and forecast units to market in a few years (no such animals yet that I know of).

One issue may be that FADEC (as described) would replace the mags and other components, and remove the pilot from direct control, relinquishing that to the computer(s), which the pilot would control via the throttle. That may be the rub...limited direct control (can you say Airbus?...caveat: that's no slam...not trying to be provocative, but I'm a Boeing guy in the jet world, and think your idea has merit in the recip world...and it may be that the engine mfgrs do as well).

I've seen FADEC in action once (a Lear 60 demo flight) and it was pretty neat...first click (throttle position) start, next click idle, click for TO, click for cruise, etc. Of course jets, with their EEC's (Electronic Engine Controls) are different beasts.

It sounds to me like you are talking somewhat of a hybrid...auto mixture, with manual backup. Click-start, click-idle, click-TO, click-cruise, click-LOP cruise, off, and it's standard control...something like that, maybe).

Cool, outside-the-box thinking, my friend. Lots of parameters to feed into the control unit, but if you figure out how to do it, with lots of redundancy, and provide a manual backup ta boot, I'll bet Lyc or TCM will send you more than a box of cubans (like free engines for life and a spot on the board of directors!)

You may have heard of all this before, but thought you might like the links to feed the fire of invention!

Cheers,
Bob

 

[Webb]

Hey Bob, I'm talking an extremely simplied version. No mag replacement, could use electronic ignition if desired. However the 2 wouldn't be linked.

The concept would parallel what a current auto pilot does. Unit off, it is totally manual, as we have it today. Unit on - it adjusts the mixture based off data from our current EMS (altitude, MP, RPM, CHT, and EGT). When at cruise, you push the LOP function button and it goes into LOP mode which can only occur at 60% or less power. If the power level goes above 60% or it can't maintain a LOP temp greater than 25 degrees, it goes to ROP. All movements through peak would be the "big pull".

The unit would be turned on at the panel. Disabling would occur by hitting a disconnect button on the stick (I've got an extra one available now) or at the panel. Releasing the lock button on the mixture knob would also disengage the servo if you needed an immediate override until you could hit the disconnect button.

A pilot would still monitor their temps just like they do now. However, the computer constantly adjusts. Climb a little, descend a little, it will give you optimal mixture.

Two components. The panel unit and a vernier cable that has a servo.

Wouldn't you think that something like would be inexpensive, a rapid install, and within our current capabilities now with the technology we have? It sounds like the Lycoming concept was far too complicated.

And Bob - A nice box of Bolivar Churchills would be an outstanding choice.

 

[rbibb]

Maybe I'm missing something but this sounds like Electronic Fuel Injection with a fail safe mode in event of computer failure. Nothing radical here other than the manual override. Your concept depends on mechanical adjustment - a more realistic, cost effective, practical, and reliable approach would be the a user input into the electronic feedback loop to adjust the mixture. Electronic ignition for the experimental market is a proven commodity, EFI is coming soon I rather suspect.

Fault tolerant electronics are very common - the fact you are reasing this is enabled by them - it just takes time for the application to the somewhat limited and highly regulated market of general aviation to develop the business case.

Some may argue the point succesfully but it is only a matter of time IMHO.

 

[TomVal]

RV8 w/FADEC

Webb,

What you are describing sounds a bit like a FADEC (Full Authority Digital Engine Control). Here are a couple links found with a Google Search on "FADEC" (some interesting reading).

Wikepedia article: http://en.wikipedia.org/wiki/FADEC
Avweb article (c1998): http://www.avweb.com/news/newacft/182749-1.html

Mooney tried the concept with the Porche Mooney PFM, but only sold 41 of them ($60,000 upgrade back then). The Avweb article said that Lycoming and Continental were working on FADEC technology back then (1998), and forecast units to market in a few years (no such animals yet that I know of).

One issue may be that FADEC (as described) would replace the mags and other components, and remove the pilot from direct control, relinquishing that to the computer(s), which the pilot would control via the throttle. That may be the rub...limited direct control (can you say Airbus?...caveat: that's no slam...not trying to be provocative, but I'm a Boeing guy in the jet world, and think your idea has merit in the recip world...and it may be that the engine mfgrs do as well).

I've seen FADEC in action once (a Lear 60 demo flight) and it was pretty neat...first click (throttle position) start, next click idle, click for TO, click for cruise, etc. Of course jets, with their EEC's (Electronic Engine Controls) are different beasts.

It sounds to me like you are talking somewhat of a hybrid...auto mixture, with manual backup. Click-start, click-idle, click-TO, click-cruise, click-LOP cruise, off, and it's standard control...something like that, maybe).

Cool, outside-the-box thinking, my friend. Lots of parameters to feed into the control unit, but if you figure out how to do it, with lots of redundancy, and provide a manual backup ta boot, I'll bet Lyc or TCM will send you more than a box of cubans (like free engines for life and a spot on the board of directors!)

You may have heard of all this before, but thought you might like the links to feed the fire of invention!

Cheers,
Bob

Bob,
I have FADEC installed on my RV8 (TMX IOF360). The good news, it is an amazing system. FADEC individually manages the fuel and ignition to each cylinder. The bad news, Aerosance, the manufacturer of my system, went out of business due to present market conditions. The good news is that Continental stepped up to the plate and is supporting the system. In the mean time, Continental is designing their own FADEC system.

The good / bad news is that the system is completely automatic. For some, the thought of a completely automatic system is not acceptable. So far, the feedback from the yahoo FADEC user’s website, operators of this system have been very satisfied. The system not only manages fuel and ignition to each cylinder, it also individually manages each cylinder to operate within its EGT and CHT limits. If a cylinder limit is being approached, the system will attempt to bring that cylinder back into normal limits.

The system also automatically sets 4 cruise power schedules based on % of power (programmed at factory). On my recent cross-county flight, I averaged 5.7 – 6.3 gph & 7500 – 9500 ft, 2400rpm (fixed pitch Catto prop), 51% power (FADEC input), IAS 160 mph. This FADEC system was an $8,500 option. Engine TBO 2400 hrs. Assuming the engine makes it to TBO (unlikely, I don’t fly often enough) the fixed cost of the system is approximately $3.54 / hr. However, the engine fuel burn is probably 10-15% more efficient than standard I/O360 engines. Some of you operators with a C/S prop and good engine leaning techniques can probably match these fuel burn figures. Where FADEC shines is that the each cylinder is individually being managed for optimum performance and engine longevity.

I don’t think the market is yet ready to embrace this level of G/A technology, however, as we gain more experience with the system and as costs come down, a market demand for the system will emerge.

Regards,

 

[nucleus]

Liberty XLII

The Liberty XLII has been certified with a continental FADEC for years.

Hans

 

[rvmills]

Webb,

It seems (to my limited brain) like all the parameters are in the EMS to pass to a computer-contolled servo in order to lean to a "best" mixture, whether that be best power or best economy/LOP (whatever "best" might be for a given condition). I'd think you'd need pretty well balanced injectors, or a pretty saavy computer, to ensure it can evaluate each cylinder's peak to keep all of 'em out of the red zone (ref your comment about 25 LOP or LOP is a no-go).

My guess is the EMC (your new baby) might be somewhat more complex than Electronic Ignition systems, which (among other things) take RPM and MP to adjust the spark advance for optimal performance (simplified view). Seems like lots more parameters to consider for mixture.

You might have to teach the EMC to adjust, wait, evaluate, then readjust in a continuous loop as well, as there is a lot to evaluate (hey, like the earlier poster said...us pilots do that now...we are sounding smarter all the time! )

But a workload-saving device as you propose is a pretty cool idea. Now, how to make it simple, yet smart enough to do the job...

Hmmm...maybe two boxes of cubanos! OBTW, I'm staying strictly hypothetical here, as going tech would quickly run me out of airspeed and ideas!

Cheers,
Bob

Hey Bob, I'm talking an extremely simplied version. No mag replacement, could use electronic ignition if desired. However the 2 wouldn't be linked.

The concept would parallel what a current auto pilot does. Unit off, it is totally manual, as we have it today. Unit on - it adjusts the mixture based off data from our current EMS (altitude, MP, RPM, CHT, and EGT). When at cruise, you push the LOP function button and it goes into LOP mode which can only occur at 60% or less power. If the power level goes above 60% or it can't maintain a LOP temp greater than 25 degrees, it goes to ROP. All movements through peak would be the "big pull".

The unit would be turned on at the panel. Disabling would occur by hitting a disconnect button on the stick (I've got an extra one available now) or at the panel. Releasing the lock button on the mixture knob would also disengage the servo if you needed an immediate override until you could hit the disconnect button.

A pilot would still monitor their temps just like they do now. However, the computer constantly adjusts. Climb a little, descend a little, it will give you optimal mixture.

Two components. The panel unit and a vernier cable that has a servo.

Wouldn't you think that something like would be inexpensive, a rapid install, and within our current capabilities now with the technology we have? It sounds like the Lycoming concept was far too complicated.

And Bob - A nice box of Bolivar Churchills would be an outstanding choice.

 

[rvmills]

Tom,

Pretty cool stuff! It'd be neat to see it in action. Couple questions (and it may relate it back to Webb's intent, so as not to stray too far OT).

How do you select between the 4 cruise power schedules? (Are there detents for TO/Climb, and each of the 4 cruise settings?)

When the computer is contolling to bring/keep the temps within limits, is it looking at low and high limits, or just high (EGT/CHT)?

Does it reference peak EGT, and is it designed for ROP only, or does it venture into the LOP range?

In a cruise setting, can you see it "auto-leaning"...ie, when you first level off and set cruise power, can you watch the FF go down slowly and see EGTs climb and then stabilize (as would be seen with manual leaning)?

Thanks, just wondering how it is to operate. Purty neat!

Cheers,
Bob

Bob,
I have FADEC installed on my RV8 (TMX IOF360). The good news, it is an amazing system. FADEC individually manages the fuel and ignition to each cylinder. The bad news, Aerosance, the manufacturer of my system, went out of business due to present market conditions. The good news is that Continental stepped up to the plate and is supporting the system. In the mean time, Continental is designing their own FADEC system.

The good / bad news is that the system is completely automatic. For some, the thought of a completely automatic system is not acceptable. So far, the feedback from the yahoo FADEC user?s website, operators of this system have been very satisfied. The system not only manages fuel and ignition to each cylinder, it also individually manages each cylinder to operate within its EGT and CHT limits. If a cylinder limit is being approached, the system will attempt to bring that cylinder back into normal limits.

The system also automatically sets 4 cruise power schedules based on % of power (programmed at factory). On my recent cross-county flight, I averaged 5.7 ? 6.3 gph & 7500 ? 9500 ft, 2400rpm (fixed pitch Catto prop), 51% power (FADEC input), IAS 160 mph. This FADEC system was an $8,500 option. Engine TBO 2400 hrs. Assuming the engine makes it to TBO (unlikely, I don?t fly often enough) the fixed cost of the system is approximately $3.54 / hr. However, the engine fuel burn is probably 10-15% more efficient than standard I/O360 engines. Some of you operators with a C/S prop and good engine leaning techniques can probably match these fuel burn figures. Where FADEC shines is that the each cylinder is individually being managed for optimum performance and engine longevity.

I don?t think the market is yet ready to embrace this level of G/A technology, however, as we gain more experience with the system and as costs come down, a market demand for the system will emerge.

Regards,

 

[Andy_RR]

Tom,
Does it reference peak EGT, and is it designed for ROP only, or does it venture into the LOP range?

Once you have FADEC, there is no such thing as ROP or LOP - only a multi-variable problem of optimising both ignition angle and air-fuel ratio.

Actually, this isn't too hard, since if you're at take-off power, you'll be running as rich as needed to generate best power (otherwise known as MBT in jargon-speak) If you're any other power level, you'll be leaned as far as you can go within cylinder and exhaust temperature limits, with the ignition angle to match.

BTW, if an Aerosance system impresses you, you'd be blown away if you found out what's going on inside a modern automotive system. The Aerosance system is so clunky it's not even as good as 1980's auto technology! It has some truly eyebrow-raising design features, IMHO.

A

 

[TomVal]

FADEC

Bob,

How do you select between the 4 cruise power schedules? (Are there detents for TO/Climb, and each of the 4 cruise settings?)

There are no detents. However, for TO/Climb, when the thrust lever is pushed within 3 degrees of full open, the system goes to best power to ensure the mixture is sufficiently rich for max performance and cooling.

The cruise setting is strictly a function of % power.

When the computer is controlling to bring/keep the temps within limits, is it looking at low and high limits, or just high (EGT/CHT)?

The system looks are low and high limits and also EGT/CHT spreads. If it is unable to control limits / spreads, a default program will activate in attempt to control the limits. If the default program fails, the remaining options are to manually vary the throttle setting, turning on the boost pump, or alternately reset the MPC’s (Master Power Control Units).

Does it reference peak EGT, and is it designed for ROP only, or does it venture into the LOP range?

The system does reference peak EGT. The ROP/LOP leaning schedules follow Lycoming I/O360 performance limits. It’s kind of funny, the engine is built by Continental’s Mattituck division, however, the engine is built and operated according to Lycoming specs.

In a cruise setting, can you see it "auto-leaning"...ie, when you first level off and set cruise power, can you watch the FF go down slowly and see EGTs climb and then stabilize (as would be seen with manual leaning)?

The cruise schedule (based on % power), is establish after 10 minutes of stabilized operation. So the FF/EGT’s change slowly over that time period. If you move the throttle position, the process starts all over again.

Below is an EFIS photo of my 7500 ft cruise @ 52% power.

Regards,

 

[rvmills]

Thanks Tom (and Andy)! Very interesting!!

Cheers,
Bob