Lean of Peak Operation On Australian Avgas?
Now this is an interesting topic.
The V35B that I fly has an IO520 - with Gami injectors.
I fly it high (rarely below A070 for any length of time), on 2300 / full throttle - which at that height is around 21" MP - ie about 65% power.
It does not have an all cylinder engine monitor - although I wish it did cause it would be interesting to play with.
Because I don't own it and I am generally not paying for the avgas myself - I fly it BY THE BOOK - which is 25C ROP.
At A100 and 2300/21" that gives me 160 TAS and 50 l/hr.
However after the Chimbu Chuckler got me thinking about this (as he does!), I have come to the conclusion that at that sort of power setting you could just lean it until it starts to run rough and then enrichen (?) it again until it is just running smoothly - and leave it at that. That gives it about 45 l/hr at A100 and 2300/21".
The reason I believe you could safely do the above is that at 65% power there is no danger of detonation and CHT <170C.
I need to check which cylinder the EGT probe is on cause in this aeroplane, I can't lean it much past Peak EGT without it running rough.
Dr
The V35B that I fly has an IO520 - with Gami injectors.
I fly it high (rarely below A070 for any length of time), on 2300 / full throttle - which at that height is around 21" MP - ie about 65% power.
It does not have an all cylinder engine monitor - although I wish it did cause it would be interesting to play with.
Because I don't own it and I am generally not paying for the avgas myself - I fly it BY THE BOOK - which is 25C ROP.
At A100 and 2300/21" that gives me 160 TAS and 50 l/hr.
However after the Chimbu Chuckler got me thinking about this (as he does!), I have come to the conclusion that at that sort of power setting you could just lean it until it starts to run rough and then enrichen (?) it again until it is just running smoothly - and leave it at that. That gives it about 45 l/hr at A100 and 2300/21".
The reason I believe you could safely do the above is that at 65% power there is no danger of detonation and CHT <170C.
I need to check which cylinder the EGT probe is on cause in this aeroplane, I can't lean it much past Peak EGT without it running rough.
Dr
2575rpm sounds right...though I too am happy to stand corrected!!!! 
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My Piper Information Manual for the Navajo/Chieftain states the MCP for the PA31-350 is 2575 RPM. At ISA the MAP would be 32-31 inches between 5k-10k.
With reference to the unfortunate Whyalla Airlines accident, I recall that the engines were being operated with reference to the engine manufacturers recommendations and not the aircraft manufacturer recommendations. As I understand it either is legally okay.
With reference to the unfortunate Whyalla Airlines accident, I recall that the engines were being operated with reference to the engine manufacturers recommendations and not the aircraft manufacturer recommendations. As I understand it either is legally okay.
Grandpa Aerotart
Andy I don't think it is as easy as you suggest.
Car 'fadec' is optomised for emission control not power or economy and the technology used is not transferable to aircraft engines...if it was it would have been.
Why do we need FADEC anyway?
Safety?
A FADEC equiped twin just had a double engine failure in Europe so there are clearly some issues to be resolved with the technology in that application...and we all know 'safety' doesn't sell anyway.
Economy?
At AUD$15-20k to install the TCM product (the only one flying) for a claimed saving of 10-15% on fuel and a minor saving in magneto maintenance...lessee 15% of the fuel flow of a typical single equals about 6 liters/hr..x $1.50 equals $9. Multiply that by a TBO of say 2000 hrs (one of the claims for FADEC is increased engine life) and that equals $18000...and I am being REALLY generous to TCMs claims here.
Looks pretty marginal to me...even in a C210/Bo...in a C172/Pa28 forget it.
About the only real driver for FADEC in non diesel aero-engine applications is lower octane fuels....i.e. the dissappearance of TEL from 100LL fuel which would give about 95 octane, apparently.
From what I have read only the Prism system can cope with that..and it copes admirably...but it isn't certified yet. It, PRISM, has been tantalisingly close for a very long time, 6 or 7 years, so why isn't it certified?
I can only assume the reason is that TEL's dissappearance from 100LL avgas is still a long way in the furure...realistically 20 years. PRISM will likely be a lot cheaper than TCMs FADEC because it is a very simple system unlike TCMs which is highly complex (and STC'd for very few aircraft anyway)...but there appears to be no market for any FADEC system yet...because it isn't cost effective.
I get the same or better economy from my Bo from balanced injectors and an all cylinder monitor, at a price point 10% that of FADEC, by simply knowing what to do with the red knob.
I get comparable safety (with no chance of the ECU stopping my engine because of a flat battery) by understanding how my engine works and understanding the engine monitor indications.
I'll say it again...FADEC is a sop for lazy (or dumb, your choice
) pilots 
Car 'fadec' is optomised for emission control not power or economy and the technology used is not transferable to aircraft engines...if it was it would have been.
Why do we need FADEC anyway?
Safety?
A FADEC equiped twin just had a double engine failure in Europe so there are clearly some issues to be resolved with the technology in that application...and we all know 'safety' doesn't sell anyway.
Economy?
At AUD$15-20k to install the TCM product (the only one flying) for a claimed saving of 10-15% on fuel and a minor saving in magneto maintenance...lessee 15% of the fuel flow of a typical single equals about 6 liters/hr..x $1.50 equals $9. Multiply that by a TBO of say 2000 hrs (one of the claims for FADEC is increased engine life) and that equals $18000...and I am being REALLY generous to TCMs claims here.
Looks pretty marginal to me...even in a C210/Bo...in a C172/Pa28 forget it.
About the only real driver for FADEC in non diesel aero-engine applications is lower octane fuels....i.e. the dissappearance of TEL from 100LL fuel which would give about 95 octane, apparently.
From what I have read only the Prism system can cope with that..and it copes admirably...but it isn't certified yet. It, PRISM, has been tantalisingly close for a very long time, 6 or 7 years, so why isn't it certified?
I can only assume the reason is that TEL's dissappearance from 100LL avgas is still a long way in the furure...realistically 20 years. PRISM will likely be a lot cheaper than TCMs FADEC because it is a very simple system unlike TCMs which is highly complex (and STC'd for very few aircraft anyway)...but there appears to be no market for any FADEC system yet...because it isn't cost effective.
I get the same or better economy from my Bo from balanced injectors and an all cylinder monitor, at a price point 10% that of FADEC, by simply knowing what to do with the red knob.
I get comparable safety (with no chance of the ECU stopping my engine because of a flat battery) by understanding how my engine works and understanding the engine monitor indications.
I'll say it again...FADEC is a sop for lazy (or dumb, your choice
) pilots
Grandpa Aerotart
FTDK with your Gamis by the time you get rough running you'll be about 80 deg F LOP EGT.
At 65% power nothing you do with the red knob will hurt your engine in any way, shape or form.
I just don't understand why someone would fit Gamis but not an engine monitor?
At 65% power nothing you do with the red knob will hurt your engine in any way, shape or form.
I just don't understand why someone would fit Gamis but not an engine monitor?
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Just a small point if I may CC, you mentioned earlier about individual cylinders and single probes etc with reference to a chieftain. Using the standard fitment for an EGT on the TIO 540, the indication given to the pilot doesn't reference any cylinders at all actually. The probe is located at the inlet to the turbocharger, at the end of some rather long exhaust plumbing. In theory, all cylinders could be lean or rich of what you actually thought they were, ie, NONE of them would actually be at the temperature indicated. It should really be called TIT. As you know, there is a difference, although in the context of what we are discussing (lean or Rich of Peak) probably not much. If anything, another reason to get a monitor I would have thought.
P.S. Re the question for max continuous for a Chieftain, 2575 RPM and full throttle is the POH answer. Take off power in other words. (Usually 41 to 43 inches.) There is another limit which many don't know about, and any chieftain fitted with a vortex kit supplied by the usual culprits, which limits max continuous to 40" and 2400 RPM, except for emergency use. (IIRC!!)
P.S. Re the question for max continuous for a Chieftain, 2575 RPM and full throttle is the POH answer. Take off power in other words. (Usually 41 to 43 inches.) There is another limit which many don't know about, and any chieftain fitted with a vortex kit supplied by the usual culprits, which limits max continuous to 40" and 2400 RPM, except for emergency use. (IIRC!!)
Last edited by morning mungrel; 30th Jun 2007 at 11:15.
CC,
I agree that the current crop of FADEC's are not convincing, but I will argue that is because they are not adopting best practice from the automotive sector (like what caused a double engine failure...)
I disagree with your statement about car and aircraft engines being completely different. They are the same animals, requiring the same parameters to be optimised. Emissions controls on cars are secondary functions to the primary role of optimal engine control.
Safety could be improved because:
a) you've got less fiddling for the pilot to do
b) the engine would always be operating within safe windows
c) the pilot could be warned of engine problems via diagnostics capability.
Like anything though, you can design it badly to have archillies heels.
Economy won't come without economies of scale. Also, until a FADEC is designed into an engines rather than seen as an add-on, it will always cost more. I work with engine controllers that have a piece cost of $US20 each, and a total system cost of maybe $US70-80. With the volumes of aero engines, you will never get this low, but AUD15-20k as an add on will never make it fly.
When 100LL is phased out (or at least when a proper UL AVGAS is made available) you will suddenly have a lot more information available to the ECU/Pilot (exhaust gas oxygen sensors, for example).
On turbocharged engines, boost control can be fully automated (and optimised).
When you use an engine monitor, you are effectively acting as the FADEC/ECU CPU. You are taking a bunch of measurements with electronic sensors and adjusting an output (the mixture lever). Why can't a dedicated bit of software do this for you 100% of the time (not just in the cruise)?
When you climb to FL100 or whatever, I'm guessing you are full rich most of the way up? There's probably another 5% fuel saving in there at least, by running optimal air-fuel ratio and ignition.
On top of that, there are some pretty interesting technologies that would provide useful capability (some of it for 'free') such as real-time engine condition monitoring, accurate fuel consumption and totalizing, combustion monitoring (spark ionization detection for example, giving peak combustion pressure position, misfire detection and knock measurement etc).
BTW, you would be absolutely astounded at what is going on within an automotive engine controller these days. They are long since done with a simple map dialling up ignition timing and injection pulsewidth. With relatively limited inputs they model and estimate pretty much everything including cylinder head temperatures, valve temperatures, exhaust temperatures, catalyst temperatures, manifold pressure, oil temperature, oil pressure etc. to within pretty close tolerances (+/-10°C on catalyst temp, for example).
If safety doesn't sell, then ease of use surely should. If not that, then extended range/payload should be another selling point.
Like I said before, the only thing that's holding it back is lawyers and economies of scale. If you could get Lycoming and TCM to agree to use a common FADEC supplier (maybe in collaboration with an existing avionics/FMS supplier like Garmin to do some clever integration) you might be able to generate enough volume and smarts to develop it and make it useful. I don't see why this can't happen. Delphi, Siemens and Bosch supply to almost all the major automotive OEMs without anyone getting too shirty about it.
A
I agree that the current crop of FADEC's are not convincing, but I will argue that is because they are not adopting best practice from the automotive sector (like what caused a double engine failure...)
I disagree with your statement about car and aircraft engines being completely different. They are the same animals, requiring the same parameters to be optimised. Emissions controls on cars are secondary functions to the primary role of optimal engine control.
Safety could be improved because:
a) you've got less fiddling for the pilot to do
b) the engine would always be operating within safe windows
c) the pilot could be warned of engine problems via diagnostics capability.
Like anything though, you can design it badly to have archillies heels.
Economy won't come without economies of scale. Also, until a FADEC is designed into an engines rather than seen as an add-on, it will always cost more. I work with engine controllers that have a piece cost of $US20 each, and a total system cost of maybe $US70-80. With the volumes of aero engines, you will never get this low, but AUD15-20k as an add on will never make it fly.
When 100LL is phased out (or at least when a proper UL AVGAS is made available) you will suddenly have a lot more information available to the ECU/Pilot (exhaust gas oxygen sensors, for example).
On turbocharged engines, boost control can be fully automated (and optimised).
When you use an engine monitor, you are effectively acting as the FADEC/ECU CPU. You are taking a bunch of measurements with electronic sensors and adjusting an output (the mixture lever). Why can't a dedicated bit of software do this for you 100% of the time (not just in the cruise)?
When you climb to FL100 or whatever, I'm guessing you are full rich most of the way up? There's probably another 5% fuel saving in there at least, by running optimal air-fuel ratio and ignition.
On top of that, there are some pretty interesting technologies that would provide useful capability (some of it for 'free') such as real-time engine condition monitoring, accurate fuel consumption and totalizing, combustion monitoring (spark ionization detection for example, giving peak combustion pressure position, misfire detection and knock measurement etc).
BTW, you would be absolutely astounded at what is going on within an automotive engine controller these days. They are long since done with a simple map dialling up ignition timing and injection pulsewidth. With relatively limited inputs they model and estimate pretty much everything including cylinder head temperatures, valve temperatures, exhaust temperatures, catalyst temperatures, manifold pressure, oil temperature, oil pressure etc. to within pretty close tolerances (+/-10°C on catalyst temp, for example).
If safety doesn't sell, then ease of use surely should. If not that, then extended range/payload should be another selling point.
Like I said before, the only thing that's holding it back is lawyers and economies of scale. If you could get Lycoming and TCM to agree to use a common FADEC supplier (maybe in collaboration with an existing avionics/FMS supplier like Garmin to do some clever integration) you might be able to generate enough volume and smarts to develop it and make it useful. I don't see why this can't happen. Delphi, Siemens and Bosch supply to almost all the major automotive OEMs without anyone getting too shirty about it.
A
Grandpa Aerotart
Andy I agree with most of what you're saying...I am just fecking with ya...mostly
I think we are a LONG way away from achieving the economies of scale that will make it cost effective...and I mean a LONG way!!!!
Why?
European move towards diesel technology.
Most light aircraft won't be effected by UL avgas..the 4 cylinder engines. That just leaves the big bore 6s in C210/Barons/Chieftains/Bonanzas etc etc.
What % of those are being operated by owners who currently baulk at even $2000 for a engine monitor/gamis?...morons
That leaves the new build aircraft...2000 units/annum?
You'll just never see the economies of scale of the automotive industry.
Oh, and the last limiting factor...although I am prepared to admit it aint that limiting...pilots like me will NEVER surrender control to a single lever FADEC system....we like being 'in the loop'.
I will fit PRISM if/when it is certified and IF 100LL goes away...not likely in the medium term. Prism is not REALLY a true FADEC..it merely optomises the ignition timing based on combustion chamber pressures etc so that everything is 100% efficient at whatever MP/RPM/Mixture I select
Nope, I often climb LOP...it is not something I advocate widely and it takes carefull speed control...but the engine doesn't know it's climbing so provided cooling airflow through the cowl is adequate it is a non issue. It probably saves several liters to TOPC. I don't do it as a SOP but if climbing to say 5000', and lightly loaded, I do. When (if) I can afford turbonormalising I will climb LOP as SOP...as it stands because I operate at full throttle all the time I can not 'recover' power and you do tend to run out of steam LOP normally aspirated.
Fully Autonimous Digital Engine Chimbu
I think we are a LONG way away from achieving the economies of scale that will make it cost effective...and I mean a LONG way!!!!
Why?
European move towards diesel technology.
Most light aircraft won't be effected by UL avgas..the 4 cylinder engines. That just leaves the big bore 6s in C210/Barons/Chieftains/Bonanzas etc etc.
What % of those are being operated by owners who currently baulk at even $2000 for a engine monitor/gamis?...morons
That leaves the new build aircraft...2000 units/annum?
You'll just never see the economies of scale of the automotive industry.
Oh, and the last limiting factor
...although I am prepared to admit it aint that limiting...pilots like me will NEVER surrender control to a single lever FADEC system....we like being 'in the loop'. I will fit PRISM if/when it is certified and IF 100LL goes away...not likely in the medium term. Prism is not REALLY a true FADEC..it merely optomises the ignition timing based on combustion chamber pressures etc so that everything is 100% efficient at whatever MP/RPM/Mixture I select
When you climb to FL100 or whatever, I'm guessing you are full rich most of the way up?
Fully Autonimous Digital Engine Chimbu
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Heya Chuck; boy, this just keep coming up, don't it. Love to see a whole bunch of GA operators send their CP, CFI and C&T pilots to that seminar and let them watch the operation of an engine (in US via a internet control)with full monitoring.
Hi Doc, didja get my PM?
Hi Doc, didja get my PM?
Grandpa Aerotart
MM thanks for that...it has been a VERY long time since I operated those engines.
Climbing them leaned and with reduced RPM (as per the accident report respondants) sends a shiver up my spine. The TSIO540 as fitted in Chieftains, Aerostar 602 etc is one of the most temperamental engines when it comes to detonation boundaries...the leaner (but still ROP) mixture and reduced RPM at 38in MAP is just asking for what happened at Whyalla.
It is bizarre that this practice is recommended in the manual.
Gami's test stand engine is a TIO-540J2BD out of a Chieftain and has probes that measure every parameter it is possible to want...I am sure if Gami wrote the POH the 'recommendations' would be very different.
Climbing them leaned and with reduced RPM (as per the accident report respondants) sends a shiver up my spine. The TSIO540 as fitted in Chieftains, Aerostar 602 etc is one of the most temperamental engines when it comes to detonation boundaries...the leaner (but still ROP) mixture and reduced RPM at 38in MAP is just asking for what happened at Whyalla.
It is bizarre that this practice is recommended in the manual.
Gami's test stand engine is a TIO-540J2BD out of a Chieftain and has probes that measure every parameter it is possible to want...I am sure if Gami wrote the POH the 'recommendations' would be very different.
Grandpa Aerotart
Andy the biggest difference between car engines and aeroplane engines is the car engines operate at maximum power for a miniscule % of their life (in fact virtually never), are water cooled and heavy as ****...aircraft engines operate continuously at power settings around 65-75% of rated power and at 100% of rated power on every takeoff...and are extremely lightly built by comparison.
This is the main reason why the Porsche engined Mooney was...hmm...less than successfull?
How long would the average car engine last at 75% power...thousands of hours or just down the street?
Engines like my IO550b are amazing pieces of technology when you think about it.
This is the main reason why the Porsche engined Mooney was...hmm...less than successfull?
How long would the average car engine last at 75% power...thousands of hours or just down the street?
Engines like my IO550b are amazing pieces of technology when you think about it.
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We had a fleet of C402's with the continental engines and the 'old type' CHT gauges. We all flew the engines the same way and never, NEVER, had an engine in for a top overhaul, period. We leaned to -50 peak cht in the cruise and enriched 1" manifold pressure/1000' on descent to the circuit. The guy that ran the hangar was always happy with the progress of the engine life. It wasn't rocket science but just looking after the donks as the manufacturer prescribed and it seemed to work. We didn't have any 'fan dangle' CHT monitoring devices, just good training and care. And this wasn't over a short period but many years. Go figure....
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Onya - yep, can be done....a PA31 operator (now defunct) ran several Chieftains from near new to the end of their operational lives (26,000hr) doing just that with never a failure to reach TBO, BUT they had only a few pilots who ALL operated in a very disciplined show in exactly the same way. The Wyalla aeroplane was flown by x number of pilots who may or may not have had an absolute understanding of what they were doing with the engines. The prang was not a result of only what happened on that flight, but a culmination of a period of inappropriate operation. A monitor not only gives the pilot info, it stores the data for the operator so the operator can identify issues BEFORE they become problems.
Grandpa Aerotart
onya we operated the C402s at Talair basically the same way...MCP/full rich on climb..100 ROP in cruise and then a gentle reduction of 1in/1000' on descent until about 25in MAP and back to about 20in on downwind...404s the same...never an issue.
But that was 15-20 years ago under a very disciplined Reg 203 airline C&Ting system and with good maintenance...new cylinders at overhaul etc etc....I don't believe these aeroplanes get the maintenance they did 15 -20 years ago and there have been quite a few well publicised quality control issues in the last 5-10 years from Lycoming and Continental. Essentially the same engines in Piper Mirages were only getting 200-300hrs from NEW to top overhaul...there is a class action by Mirage owners against Lycoming as a result.
Take a look at the pictures of the cylinders and pistons in that Whyalla accident report link on page 1...they are THRASHED!
I believe the crankshaft let go because of a pre existing fault from the factory...remember this is right in the middle of the big Lycoming TIO540 crankshaft recall but for some reason ATSB feels thats not hugely relevant.
The remaining engine failed with a big hole melted through a piston...what caused that?
Heat...and probably not all in one flight or even 10...although if the young chap bumped up the MAP/RPM to MCP and forgot to enrichen the mixture, and lets face it who among us has not done that?, it well could have happened in a matter of minutes but more likely over 100s of hours.
Like I said earlier that graph I posted back at the beginning of the thread is Gami data from a TIO540J2BD Chieftain engine, which they deliberately induce detonation in. Plot the climb MAP/FF settings and see where you end up on the graph...then think about slightly reduced RPM as well which has a huge effect on combustion chamber peak pressures and temps.
Even if they didn't bother with the balanced injectors but installed the engine monitors and operated as per POH recommendations they'd soon see what was (really) going on inside the engines and may well have modified their practices to be more in line with the few operators that were operating them in a more mechanically sympathetic manner on climb and in cruise.
The TIO540 was a good engine...but not the most tolerant of misshandling....15-20 years ago fuel was cheap, cylinders were cheap (and better built) engine cooling baffles and engine instrumentation was new.
That is not the case anymore.
But that was 15-20 years ago under a very disciplined Reg 203 airline C&Ting system and with good maintenance...new cylinders at overhaul etc etc....I don't believe these aeroplanes get the maintenance they did 15 -20 years ago and there have been quite a few well publicised quality control issues in the last 5-10 years from Lycoming and Continental. Essentially the same engines in Piper Mirages were only getting 200-300hrs from NEW to top overhaul...there is a class action by Mirage owners against Lycoming as a result.
Take a look at the pictures of the cylinders and pistons in that Whyalla accident report link on page 1...they are THRASHED!
I believe the crankshaft let go because of a pre existing fault from the factory...remember this is right in the middle of the big Lycoming TIO540 crankshaft recall but for some reason ATSB feels thats not hugely relevant.
The remaining engine failed with a big hole melted through a piston...what caused that?
Heat...and probably not all in one flight or even 10...although if the young chap bumped up the MAP/RPM to MCP and forgot to enrichen the mixture, and lets face it who among us has not done that?, it well could have happened in a matter of minutes but more likely over 100s of hours.
Like I said earlier that graph I posted back at the beginning of the thread is Gami data from a TIO540J2BD Chieftain engine, which they deliberately induce detonation in. Plot the climb MAP/FF settings and see where you end up on the graph...then think about slightly reduced RPM as well which has a huge effect on combustion chamber peak pressures and temps.
Even if they didn't bother with the balanced injectors but installed the engine monitors and operated as per POH recommendations they'd soon see what was (really) going on inside the engines and may well have modified their practices to be more in line with the few operators that were operating them in a more mechanically sympathetic manner on climb and in cruise.
The TIO540 was a good engine...but not the most tolerant of misshandling....15-20 years ago fuel was cheap, cylinders were cheap (and better built) engine cooling baffles and engine instrumentation was new.
That is not the case anymore.
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YesTAM
Hi YesTAM,
Any chance of finding some details on the author of the comments given at the forum on care and feeding of the particular aircraft engines not refered to?
I, and many others would be very interested in hearing his reasoning and explanation on inferior Australian avgas, and how LOP v ROP supposedly reduces detonation margins in this particular circumstance.
As he/she appears to be an individual appointed to a position of educator it is only reasonable that such a controversial statement be given the opportunity for broad peer review.
The individual may well be onto something, although for the life of me I can't see it at the moment, however a few post from the person outlining the claim and I'm sure we will get to the truth.
How about it YesTAM?
I'm sure you could source the details and then privately invite him to contribute to the thread, or pm me with the details and I'll extend an invitation.
Regards
M
Any chance of finding some details on the author of the comments given at the forum on care and feeding of the particular aircraft engines not refered to?
I, and many others would be very interested in hearing his reasoning and explanation on inferior Australian avgas, and how LOP v ROP supposedly reduces detonation margins in this particular circumstance.
As he/she appears to be an individual appointed to a position of educator it is only reasonable that such a controversial statement be given the opportunity for broad peer review.
The individual may well be onto something, although for the life of me I can't see it at the moment, however a few post from the person outlining the claim and I'm sure we will get to the truth.
How about it YesTAM?
I'm sure you could source the details and then privately invite him to contribute to the thread, or pm me with the details and I'll extend an invitation.
Regards
M
Andy the biggest difference between car engines and aeroplane engines is the car engines operate at maximum power for a miniscule % of their life
FADEC ? A work in progress. When it can consistantly match what I can achieve with a good EMS, I'll plump for the FADEC. Until then I'll continue to tweak, fondle and caress the throttle, prop and mixture controls.
Last edited by gassed budgie; 1st Jul 2007 at 09:35.
Grandpa Aerotart
Until then I'll continue to tweak, fondle and caress the throttle, prop and mixture controls.
Sometimes I feel like I am the only one out here fondling my knobs
I find it instructive to think about the life span of racing car engines..still probably not operating at the % power that my IO550 operates at for 1000s of hours and they are lucky to last 1 race...and if they do they are stripped and rebuilt before the next race.
Andy in the year of greatest light aircraft production, 1979, 17000 odd units were wheeled out of sundry Beech/Piper/Cessna factories. In mid 80s that dropped to near zero and since then 10% of that has rarely been achieved. Even if that number was an average we wouldn't have the economies of scale of car production.
It's the same deal with avgas...up until the mid/late 60s most airliners were pistons...my father transferred from the DC4 to the B707 at QF in 1969...when the big piston airliners went away so to did the demand for avgas...since then the demand has been all downhill..when leaded car fuel went away in the 80s that was another big hit on avgas because it suddenly became the only fuel with TEL (a miniscule amount BTW). Nowadays avgas is about 1% of all gasoline production and not only does it have TEL in it (expensive ****) but it is at the higher end of the mogas qualitity range as well...it isn't just the lead that makes avgas expensive...be it Australian avgas or any other country's avgas.
"Sometimes I feel like I am the only one out here fondling my knobs"
Not really much else to do these days on long legs in a lightie between frequency changes every 30 min or so !
That's why I need one of them all cylinder monitor thingies - so I got something else to play with!
Dr
Not really much else to do these days on long legs in a lightie between frequency changes every 30 min or so !
That's why I need one of them all cylinder monitor thingies - so I got something else to play with!
Dr
Last edited by ForkTailedDrKiller; 2nd Jul 2007 at 00:04.
Grandpa Aerotart
FTDK tried to answer your PM but your inbox is full...just left a message on your mobile answering service too...don't you ever answer the fecking thing?
Last edited by Chimbu chuckles; 1st Jul 2007 at 06:17.