Diesel V8 flys
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27/09
Yes, you're right about a loss of power. I'm thinking that statistics are on the side of electrics though. Ignoring all the failure modes common to both engine types (cylinders, crankshafts, carburettor/fuel rail etc), which is more likely to fail: a pair of magnetos with associated drive shafts, wiring and plugs, or a pair of FADECs with associated electrical supply and wiring loom? I guess the aero-diesels are still too recent an invention to answer that question here. But long term, my money is on solid state electronics over mechanical parts, any day.
For the Diamond in particular to have a power failure these days, post-power-loss-incident, you'd have to lose the alternator(s), lose the main battery, then lose the dedicated FADEC backup battery. That's a lot of failures!
I would imagine that other manufacturers will probably learn from failures of the past, and have similar levels of redundancy.
But as I said, it's not the electrics that tend to fail on these things. It's the mechanical parts, including the cylinder head gasket (very high cylinder peak pressures). I watch this new CGI thing with interest!
Yes, you're right about a loss of power. I'm thinking that statistics are on the side of electrics though. Ignoring all the failure modes common to both engine types (cylinders, crankshafts, carburettor/fuel rail etc), which is more likely to fail: a pair of magnetos with associated drive shafts, wiring and plugs, or a pair of FADECs with associated electrical supply and wiring loom? I guess the aero-diesels are still too recent an invention to answer that question here. But long term, my money is on solid state electronics over mechanical parts, any day.
For the Diamond in particular to have a power failure these days, post-power-loss-incident, you'd have to lose the alternator(s), lose the main battery, then lose the dedicated FADEC backup battery. That's a lot of failures!
I would imagine that other manufacturers will probably learn from failures of the past, and have similar levels of redundancy.
But as I said, it's not the electrics that tend to fail on these things. It's the mechanical parts, including the cylinder head gasket (very high cylinder peak pressures). I watch this new CGI thing with interest!
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Back in 1963, I had a BSA motorcycle, equipped with an Alternator, courtesy of Lucas, AKA "the Prince of Darkness" (Though their official slogan was "King of the Road")
The rotor contained permanent-magnets, therefore self-exciting, Rectification bt Selenium, superseded rapidly by Cilicon semiconductors. Aswitching arrangement Changed stator-coils from parallel to series configuration, according to switched load....an emergency position allowed kick-starting with a totally flat battery. as the battery voltage increased, it opposed the alty output and caused misfiring...a crude and effective system.....I must add,this was 6-volt. the later 12-Volt systems had a Zener Diode to dumpsurplusoutput.
A very simple, robust and cheap item to incorporate into an aircraft engineand the whole caboodle canbe internal! Battery-system could still be used , via blocking diodes...with a built-in alty and twin FADECs, such an engine should be far more reliable than the magneto-fed Lycosaurus breed.
The cost of electronic components, at these power-levels, is buttons. As a previous poster stated, components could be derated for longevity and Ireckon youcould probably double the power-handling capability for less than $5 AUD
per circuit-board.
For the cost and weight-penalty,there's no reason I can think of, why every engine should not have a spare, ready-mounted FADEC unit...in case of a failure "out bush" simply swap the plugs to the spare unit.......If a magneto goes sick, even an experienced fitter will struggle if, say,the points-spring has cracked or the condenser gone U/s.
Time to move into the 21st.Century!
The rotor contained permanent-magnets, therefore self-exciting, Rectification bt Selenium, superseded rapidly by Cilicon semiconductors. Aswitching arrangement Changed stator-coils from parallel to series configuration, according to switched load....an emergency position allowed kick-starting with a totally flat battery. as the battery voltage increased, it opposed the alty output and caused misfiring...a crude and effective system.....I must add,this was 6-volt. the later 12-Volt systems had a Zener Diode to dumpsurplusoutput.
A very simple, robust and cheap item to incorporate into an aircraft engineand the whole caboodle canbe internal! Battery-system could still be used , via blocking diodes...with a built-in alty and twin FADECs, such an engine should be far more reliable than the magneto-fed Lycosaurus breed.
The cost of electronic components, at these power-levels, is buttons. As a previous poster stated, components could be derated for longevity and Ireckon youcould probably double the power-handling capability for less than $5 AUD
per circuit-board.
For the cost and weight-penalty,there's no reason I can think of, why every engine should not have a spare, ready-mounted FADEC unit...in case of a failure "out bush" simply swap the plugs to the spare unit.......If a magneto goes sick, even an experienced fitter will struggle if, say,the points-spring has cracked or the condenser gone U/s.
Time to move into the 21st.Century!
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Unlike a Turbocharged avgas burner, you will not get flying behind one, and I do not imagine many folk would be keen either when they fly over high country like the west of the USA.
Anyone know why?
Anyone know why?
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Jabawocky - Yes, because there's a risk of a diesel engine with a set fuel injection ratio overheating at very high altitudes.
The turbocharger speeds up substantially (and therefore heats up more) with the thin air at high altitudes, and there's less exhaust back pressure because of the thin air.
If an aftercooler is fitted, the charge air reaches a higher temperature because of the reduced effectiveness of the aftercooler.
Diesel-powered ground equipment such as trucks and earthmovers are de-rated with adjustments to the fuel injection pumps, when operating at extremely high altitudes, such as in the Rockies or the Andes. This is done to prevent engine damage caused by overheating in the thin air.
If an automatic electronic fuel injection control was fitted to this aviation diesel V8, it would compensate for the thin air at high altitudes.
I seem to recall the Junkers Jumo ran to 41,000', but I'm not sure how the thin air problem was compensated for, in the Jumos.
The turbocharger speeds up substantially (and therefore heats up more) with the thin air at high altitudes, and there's less exhaust back pressure because of the thin air.
If an aftercooler is fitted, the charge air reaches a higher temperature because of the reduced effectiveness of the aftercooler.
Diesel-powered ground equipment such as trucks and earthmovers are de-rated with adjustments to the fuel injection pumps, when operating at extremely high altitudes, such as in the Rockies or the Andes. This is done to prevent engine damage caused by overheating in the thin air.
If an automatic electronic fuel injection control was fitted to this aviation diesel V8, it would compensate for the thin air at high altitudes.
I seem to recall the Junkers Jumo ran to 41,000', but I'm not sure how the thin air problem was compensated for, in the Jumos.
One track. Electronic injection for diesels compensates and enhances the cycle. Cannot say for the trucks I am driving but my common rail family hack is firing up to four times per power stroke. You are correct with the rack settings for traditional injector systems. Caterpillar placard their machines for work above a certain altitude...methinks 15000ft, if I remember correctly, bit of a giggle in this country...soooo, going by the monitoring circuits built in current common rail systems...I reckon the Bosch system will compensate for altitude.
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Turbines with fadec run what we call PMA permanent magnetic alternator's they provide power to the FADEC system alone in emergency use when normal power is lost. And as such the engine will continue to run A classic example was the A380 all power lost to #1 engine but ran till they got enough foam into it to put the flame out.
The biggest problem with a diesel engine it has extremely bad hamomonics due to its power stoke is based on compression. A long time ago as I recall the French put one in a TB10 or 20. After the test flight and taxing back the tail fell of. This isn't the first time that has happen if they get it all wrong in the design stage has happened to normal type engines as well.
From what I recall you have to run a special prop with a rubber drive and increase the size of the engine mounts as well. Ever look a a late model car engine mounts now some are even computer controlled for better NVH especially when they drop out cylinder's for better fuel economy.
John dere made a rotary engine it was around 500hp from memory they could not get it to work Lcy brought it they ended up with a 500hp engine and a gear box of 2500hp rating to keep it all together then they gave up on the project.
The biggest problem is its extremely hard to go past what we have now as the norm that's because believe it or not they got it very close to perfect from the start. With modern machinery better alloys they made big increases in reliability but the basic confrig is still the same. Auto engines don't work in aviation its that simple, name one that dose. Only the VW engine works but that's not in commercial use.
For there investment I wish them well but it is going to be a hard road ahead for them. It dose look like a quality product I will give them that. Will it work only time will tell or will it end up like a lot that have gone before them lets see.
Cheers
The biggest problem with a diesel engine it has extremely bad hamomonics due to its power stoke is based on compression. A long time ago as I recall the French put one in a TB10 or 20. After the test flight and taxing back the tail fell of. This isn't the first time that has happen if they get it all wrong in the design stage has happened to normal type engines as well.
From what I recall you have to run a special prop with a rubber drive and increase the size of the engine mounts as well. Ever look a a late model car engine mounts now some are even computer controlled for better NVH especially when they drop out cylinder's for better fuel economy.
John dere made a rotary engine it was around 500hp from memory they could not get it to work Lcy brought it they ended up with a 500hp engine and a gear box of 2500hp rating to keep it all together then they gave up on the project.
The biggest problem is its extremely hard to go past what we have now as the norm that's because believe it or not they got it very close to perfect from the start. With modern machinery better alloys they made big increases in reliability but the basic confrig is still the same. Auto engines don't work in aviation its that simple, name one that dose. Only the VW engine works but that's not in commercial use.
For there investment I wish them well but it is going to be a hard road ahead for them. It dose look like a quality product I will give them that. Will it work only time will tell or will it end up like a lot that have gone before them lets see.
Cheers
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Onetrack it is not px that drives the turbo it velocity that drives it.It only changes to px across the turbine . Velocity is the in the exhaust system is what is required that's why it has a convergent scoll onto the turbine.
Cheers
Cheers
yr right, pressure is velocity when it comes to gasses - heard of dynamic pressure?
At a molecular level, all pressure is is the velocity/kinetic energy of the particles
regarding diesels at altitude, you can drive your common-rail diesel-powered car/truck/what-have-you to more than 10000' AMSL in many parts of the world and not have it stop/break-down/overheat/fail to start. What's the difference if it's air in the tyres or air under the wings that's keeping the crankcase off the ground...?
At a molecular level, all pressure is is the velocity/kinetic energy of the particles
regarding diesels at altitude, you can drive your common-rail diesel-powered car/truck/what-have-you to more than 10000' AMSL in many parts of the world and not have it stop/break-down/overheat/fail to start. What's the difference if it's air in the tyres or air under the wings that's keeping the crankcase off the ground...?
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yr right - Well perhaps I should have made it clearer that the turbocharger on a diesel spins at much faster speeds in thin air, because the engine is running hotter.
The speed of a diesel engine turbocharger is directly governed by the EGT. The higher the temperature of the exhaust gases, the greater the turbine speed.
This is a self-compensating system for high altitude in one respect - that's the reason why many diesel drivers on the ground don't notice much power drop-off in the top of the Alps, the Rockies or the Andes.
However, the engine operating temperature of a diesel is the critical factor to watch at high altitudes.
The speed of a diesel engine turbocharger is directly governed by the EGT. The higher the temperature of the exhaust gases, the greater the turbine speed.
This is a self-compensating system for high altitude in one respect - that's the reason why many diesel drivers on the ground don't notice much power drop-off in the top of the Alps, the Rockies or the Andes.
However, the engine operating temperature of a diesel is the critical factor to watch at high altitudes.
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Sorry px is not velocity at all.
Px increase velocity decreases temp increases
Or
Px decrease velocity increases temp decreases
All at subsonic flows
If what you say is true there would no need ford the convergent scroll.
Cheers
Px increase velocity decreases temp increases
Or
Px decrease velocity increases temp decreases
All at subsonic flows
If what you say is true there would no need ford the convergent scroll.
Cheers
When you live....
Thread Starter
From the website - their old website had videos of the engine running at altitude:
EPS | Ground Testing
EPS has been testing the Proof-of-Concept Engine on its mobile test stand since November 2011. In a program known in the automotive world as “accelerated durability testing,” the team has run the engine through extremes that will never be experienced in the course of normal aircraft operations, including calibrations, low inertia props, cold tests, multiple rapid acceleration and deceleration cycles, and a battery of other insults to put the engine through its paces. In the summer of 2013, EPS drove the engine to the top of Mount Evans in Colorado to conduct high altitude performance tests at 10,000 and 15,000 MSL. The engine achieved full 350 horsepower operation at 15,000 feet density altitude and achieved 420 horsepower at low altitude. The engine’s liquid cooling system has been tested in extreme weather conditions, demonstrating starts in temperatures from – 25 degrees F to more than 100 degrees F. Based on hundreds of hours of testing as of April 2014, EPS can report significant technical breakthroughs, including
Your handle on thermodynamics and fluid dynamics seems a little limited, if you say this. BTW, the scroll is not the convergent/divergent part of a radial-flow turbine. The turbine itself is.
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The scroll is a convergent duct. It goes from a large to small. There fore it must increase it's velocity and decrease it's px due gas laws. Once it passes over the turbine it changes as in any gas turbine Engine
Cheers
Cheers
The scroll appears to be convergent to the ill-informed, but it's just getting smaller because gas is escaping through the turbine wheel. The pressure/velocity is nominally constant around the scroll/volute. The pressure/velocity change happens as the gas passes through the turbine/compressor wheel. If it happens anywhere else it would represent lost mechanical work - i.e. inefficiency.
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The turbocharged diesel cycle engine I used to fly, was certificated up to 20,000'.
So I guess the turbocharger was designed correctly to run in less dense air, without overheating.
I'm also going to guess that the manufacturer of this new V8 engine might have also designed it to run safely at altitude. Only a guess mind you...
But you'd want to be sure of mechanical reliability before you flew it over the Rockies, for sure. Or even our humble high country!
So I guess the turbocharger was designed correctly to run in less dense air, without overheating.
I'm also going to guess that the manufacturer of this new V8 engine might have also designed it to run safely at altitude. Only a guess mind you...
But you'd want to be sure of mechanical reliability before you flew it over the Rockies, for sure. Or even our humble high country!
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A Cirrus SR22 powered by an Engineered Propulsion Systems (EPS) Graflight V-8 Diesel engine made its first test flight May 2nd in Mojave, CA with Dick Rutan at the controls of the airplane.
A Successful Test Flight For EPS Engine | Aero-News Network
A Successful Test Flight For EPS Engine | Aero-News Network
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Anyone know what happens to a TC or TN avgas burner when an intake tube coupling leaks or as they do lets go? Yeah you get a NA engine. 
A mixture sweep sorts that but you can have power to divert safely.
What happens on these turbo diesels?
A mixture sweep sorts that but you can have power to divert safely.What happens on these turbo diesels?