DA42 Musings......... (Split from another thread and Merged with older thread)
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A P2006 is 235k Euro...
Two things immediately occur:
- Single engine performance near MAUW?
- Cost of operation when Mogas is no longer available due to the bio fuel content?
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Repeated...
If you want a modern twin with low operating costs, full IFR, 4 seats and nice reliable engines (Rotax 912S) why not go for;
http://www.tecnamaircraft.com/Tecnam_P2006T.htm
Should burn 30lph (Mogas) at 147kn
Rod1
PS Biofuel will probably be no problem, just bioethanal which is only one version.
Climb rate, s.l. (single engine) 380 fpm
If you want a modern twin with low operating costs, full IFR, 4 seats and nice reliable engines (Rotax 912S) why not go for;
http://www.tecnamaircraft.com/Tecnam_P2006T.htm
Should burn 30lph (Mogas) at 147kn
Rod1
PS Biofuel will probably be no problem, just bioethanal which is only one version.
Climb rate, s.l. (single engine) 380 fpm
Last edited by Rod1; 30th Nov 2007 at 18:09.
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Had a look at the spec sheet, sounds pretty good (on pdf at least 
). One thing that would bother me a bit is the range, this could be better. Also the service ceiling on one engine isn't too great - if one donk fails, you'll be heading down pretty quickly, by the sounds of this (have to admit very little twin knowledge, so don't know how this compares).
What is very nice is the Mogas which makes a lot more places accessible.
How reliable are Rotax 912s ?
). One thing that would bother me a bit is the range, this could be better. Also the service ceiling on one engine isn't too great - if one donk fails, you'll be heading down pretty quickly, by the sounds of this (have to admit very little twin knowledge, so don't know how this compares).What is very nice is the Mogas which makes a lot more places accessible.
How reliable are Rotax 912s ?
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“How reliable are Rotax 912s ?”
It has been certified for some time and there are very large numbers in use. In the UK PFA fleet the Rotax 912 range is considered to be the most reliable engine in the fleet, beating the old US engines. I am very impressed with my 912s, but like you I know next to nothing about twins.
On the surface it looks like a revolutionary approach, which will give the DA42 a hard time on the value for money front. Tecnam have a good name in the VLA/Micro/LSA world.
Rod1
It has been certified for some time and there are very large numbers in use. In the UK PFA fleet the Rotax 912 range is considered to be the most reliable engine in the fleet, beating the old US engines. I am very impressed with my 912s, but like you I know next to nothing about twins.
On the surface it looks like a revolutionary approach, which will give the DA42 a hard time on the value for money front. Tecnam have a good name in the VLA/Micro/LSA world.
Rod1
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Look dont kid yourselves the DA42 is not an all weather go any where airways aircraft.
At the top end of GA are the turboprops. The aircraft are designed for "serious" airways operation. They have the performance, the redundancy of equipment, and the "technology" to deal with most weather. Dont bother if you want to fly extensively outside the airways and appeciate you will need not only an IR but a type rating.
At the next level are the more robust twins - most of vintage. Aircraft like the Aztec, Beech etc with a modern instrument refit are capable of coping with most weather and have the performance to ensure a reasonable safety margin on one engine in most circumstances. For example an Aztec fully loaded even with a reasonably ham fisted pilot will have the power to climb away in most circumstances at a healthy rate.
At the next level comes the 42. It does most of the things achieved by the more robust twins but its single engine performace at MTOW is hardly staggering, and I am not convinced it gives the best ride in rough conditions. Personally I think you would rather be in an Aztec for example when the going gets rough than in a 42 - if not by a wide margin.
Finally may come the new Tecnam. Of course the jury is out and it would be unfair to reach any conclusions yet. Probably its performance will be less good by another margin from the 42. Moreover, I dont think the engines are injected and I guess it will not be deiced - significant restrictions for an all weather twin. What it might offer is relatively cheap capable touring with the added security of two engines over water or hostile terrain.
At the top end of GA are the turboprops. The aircraft are designed for "serious" airways operation. They have the performance, the redundancy of equipment, and the "technology" to deal with most weather. Dont bother if you want to fly extensively outside the airways and appeciate you will need not only an IR but a type rating.
At the next level are the more robust twins - most of vintage. Aircraft like the Aztec, Beech etc with a modern instrument refit are capable of coping with most weather and have the performance to ensure a reasonable safety margin on one engine in most circumstances. For example an Aztec fully loaded even with a reasonably ham fisted pilot will have the power to climb away in most circumstances at a healthy rate.
At the next level comes the 42. It does most of the things achieved by the more robust twins but its single engine performace at MTOW is hardly staggering, and I am not convinced it gives the best ride in rough conditions. Personally I think you would rather be in an Aztec for example when the going gets rough than in a 42 - if not by a wide margin.
Finally may come the new Tecnam. Of course the jury is out and it would be unfair to reach any conclusions yet. Probably its performance will be less good by another margin from the 42. Moreover, I dont think the engines are injected and I guess it will not be deiced - significant restrictions for an all weather twin. What it might offer is relatively cheap capable touring with the added security of two engines over water or hostile terrain.
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I suppose Mooney's were good 50 years ago
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At the next level comes the 42. It does most of the things achieved by the more robust twins but its single engine performace at MTOW is hardly staggering
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I suppose Mooney's were good 50 years ago "Please tell me then why in 2007 this 50 year old model is still one of the most economic planes around ?"
Englishal,
You are correct that Mooneys were good 50 years ago - in fact they were great and still are. A 30 year old Mooney will outrun a new DA-42, use less fuel in the process, not have the risk of in flight engine failure the Thielert has (22 in flilght stoppages so far according to aviation consumer) and look a damned sight better.
The Mooney airframe (like the bonanza airframe) is an iconic design which is very difficult to improve upon.
Next time you are near a new Mooney, take a look at the build quality, you cannot even get a credit card between the elevator and the tailplane, or rudder/fin, or aileron/wing. Look how thin the tail plane is in cross section and compare it to a PA-28/DA-42. Notice the all-trimming tailplane to avoid the extra drag of trim tabs. Look at the fully enclosed gear doors - these enclose the gear and cause less drag than most bizjet RG systems. Look at the FIKI approved TKS system. In addition to the genius design skills of Al Mooney this airframe has been tweaked and improved progressively over 50 years by visionaries such as Roy Lo Presti. But efficiency is the key to how good the machine is and the Mooney is unbeatable. Let me repeat that, the Mooney is unbeatable in its class.
The Mooney build quality is also incomparably better than anything in its class. Diamond have a long way to go before they begin to get close to this (or the 200+ kt figure they promised with the twinstar).
But I suppose, you may prefer 155kts in a plastic bathtub as opposed to 192kts in a handcrafted piece of Texan aluminium?
Chacun a son gout,
SB
Englishal,
You are correct that Mooneys were good 50 years ago - in fact they were great and still are. A 30 year old Mooney will outrun a new DA-42, use less fuel in the process, not have the risk of in flight engine failure the Thielert has (22 in flilght stoppages so far according to aviation consumer) and look a damned sight better.
The Mooney airframe (like the bonanza airframe) is an iconic design which is very difficult to improve upon.
Next time you are near a new Mooney, take a look at the build quality, you cannot even get a credit card between the elevator and the tailplane, or rudder/fin, or aileron/wing. Look how thin the tail plane is in cross section and compare it to a PA-28/DA-42. Notice the all-trimming tailplane to avoid the extra drag of trim tabs. Look at the fully enclosed gear doors - these enclose the gear and cause less drag than most bizjet RG systems. Look at the FIKI approved TKS system. In addition to the genius design skills of Al Mooney this airframe has been tweaked and improved progressively over 50 years by visionaries such as Roy Lo Presti. But efficiency is the key to how good the machine is and the Mooney is unbeatable. Let me repeat that, the Mooney is unbeatable in its class.
The Mooney build quality is also incomparably better than anything in its class. Diamond have a long way to go before they begin to get close to this (or the 200+ kt figure they promised with the twinstar).
But I suppose, you may prefer 155kts in a plastic bathtub as opposed to 192kts in a handcrafted piece of Texan aluminium?
Chacun a son gout,
SB
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Have followed this thread so far, and it seems as if people would rather defend their particular viewpoint than admit to problems.
Fact is there are two ways to operate diesel engines, mechanical or electronic.
Mechanical ones (with fuel pump & injectors) keep going without electrical power. Electronic (common rail & ECU) do NOT keep going without electrical power. Thielert chose to develop an electronic system and this is inherently unsuitable for aircraft use. The inevitable back-up systems that are needed defeat the main advantage of diesel power, reliability, economy, and long life.
Sad really.
Fact is there are two ways to operate diesel engines, mechanical or electronic.
Mechanical ones (with fuel pump & injectors) keep going without electrical power. Electronic (common rail & ECU) do NOT keep going without electrical power. Thielert chose to develop an electronic system and this is inherently unsuitable for aircraft use. The inevitable back-up systems that are needed defeat the main advantage of diesel power, reliability, economy, and long life.
Sad really.
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Having flown both Mooney M20J (now a 30 year old model) and DA42, guess what? They are both great aeroplanes.
The M20J cruised at 155kt at 9,000ft and burned about 11 US gal per hour at 50 degrees rich of peak. Never could get it to run smoothly lean of peak, a common problem with stock avgas engines and their very primitive fuel injection systems. The higher cruise figures (192kt was mentioned) are for the current Mooney models with bigger engines, and they have far higher fuel burns of course.
And the DA42 cruises at 155kt at 9,000ft burning 12 US gal per hour. Rather impressive that a twin, carrying all the weight and drag of the second engine and the fuel to feed it, can pretty much match the performance and economy of that old Mooney. And this DA42 is equipped with TKS, which knocks several knots off cruise speed. The M20J had no de-icing. I've also flown a non-TKS DA42 which gave the same performance at 10.5 US gal per hour.
Vee-tail-1, could you explain why you think FADEC controlled diesels are inherently unsuitable for aircraft use? What are the back up systems you refer to? Surely it's difficult to substantiate such a statement with hundreds of diesel-powered aircraft out there and order books for hundreds more?
The M20J cruised at 155kt at 9,000ft and burned about 11 US gal per hour at 50 degrees rich of peak. Never could get it to run smoothly lean of peak, a common problem with stock avgas engines and their very primitive fuel injection systems. The higher cruise figures (192kt was mentioned) are for the current Mooney models with bigger engines, and they have far higher fuel burns of course.
And the DA42 cruises at 155kt at 9,000ft burning 12 US gal per hour. Rather impressive that a twin, carrying all the weight and drag of the second engine and the fuel to feed it, can pretty much match the performance and economy of that old Mooney. And this DA42 is equipped with TKS, which knocks several knots off cruise speed. The M20J had no de-icing. I've also flown a non-TKS DA42 which gave the same performance at 10.5 US gal per hour.
Vee-tail-1, could you explain why you think FADEC controlled diesels are inherently unsuitable for aircraft use? What are the back up systems you refer to? Surely it's difficult to substantiate such a statement with hundreds of diesel-powered aircraft out there and order books for hundreds more?
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But I suppose, you may prefer 155kts in a plastic bathtub as opposed to 192kts in a handcrafted piece of Texan aluminium?
I would actually prefer a TS over a Mooney. No doubt the Mooney is an excellent aeroplane (though both would be too much of a handful for Sternone's level of experience), but I'd prefer the second engine. I "failed" the critical engine in a TS in California and managed to climb quite comfortably to 9500 3 up and lots of fuel at over 300 fpm all the way up. I left Palm Springs a few weeks ago with 4 up, full fuel and 30C, and had no problems with performance.The problem with these old designs like the Mooney is that were never designed with safety in mind - just like old cars. You'd be more likely to survive a crash in a TS than a Mooney, the TS has been designed with a 25G safety cell and seats for a start....
Anyway, eash to their own....On the subject of the TKS, I thought that actually increased the top speed of the TS due to the differences in leading edge of the wing with and without.
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soay. Please keep up with progress, particularly in France.
The Dieselis, has a mechanical Isuzu turbo-diesel, the Gaz-ailes has a mechanical Citroen AX 1.4 diesel. Jodels like the Delvion and other models use a variety of mechanical diesel engines, from Citroen, Peugeot, and Toyota.
http://gazaile2.free.fr & http://delvion.free.fr
mister jellybean.
Surely you are aware that a complete electrical failure on a Thielert powered aircraft means loss of the engine. The electronic control of the diesel injection system works by electricity. No electricity..no injection..no motor. Call it FADEC or ECU or whatever, if the electrics fail, and the two batteries(one for backup) go flat, you will lose the motor. Makes no difference how many FADECS or backup control systems you have, the common rail diesel injection system is totally reliant on an electrical power supply. Long ago aircraft engines were fitted with magnetos so that if everything failed at least the motor would keep going. Not so this new Thielert electronic diesel.
The Dieselis, has a mechanical Isuzu turbo-diesel, the Gaz-ailes has a mechanical Citroen AX 1.4 diesel. Jodels like the Delvion and other models use a variety of mechanical diesel engines, from Citroen, Peugeot, and Toyota.
http://gazaile2.free.fr & http://delvion.free.fr
mister jellybean.
Surely you are aware that a complete electrical failure on a Thielert powered aircraft means loss of the engine. The electronic control of the diesel injection system works by electricity. No electricity..no injection..no motor. Call it FADEC or ECU or whatever, if the electrics fail, and the two batteries(one for backup) go flat, you will lose the motor. Makes no difference how many FADECS or backup control systems you have, the common rail diesel injection system is totally reliant on an electrical power supply. Long ago aircraft engines were fitted with magnetos so that if everything failed at least the motor would keep going. Not so this new Thielert electronic diesel.
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Jellybean
Statistically you are safer in a single than a twin. OK, that ignores several factors that vary the risk, but even though I have more than 1000 hours in MEPs I would prefer, day VMC, to be in a light single than a light twin unless I was over an inhospitable surface, such as water, for a long time. Twin has twice the chance of failure. Even higher with the TAE unit.
What I can't believe is that an operator got an AOC for the things. There is no way that they could fly safely at night, because it is almost impossible to stay within 30 mins of a suitable alternate when most are closed. Any more then you could lose an engine, have the overload blow the other alternator if it's weak, and be completely screwed!
Statistically you are safer in a single than a twin. OK, that ignores several factors that vary the risk, but even though I have more than 1000 hours in MEPs I would prefer, day VMC, to be in a light single than a light twin unless I was over an inhospitable surface, such as water, for a long time. Twin has twice the chance of failure. Even higher with the TAE unit.
What I can't believe is that an operator got an AOC for the things. There is no way that they could fly safely at night, because it is almost impossible to stay within 30 mins of a suitable alternate when most are closed. Any more then you could lose an engine, have the overload blow the other alternator if it's weak, and be completely screwed!
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Vee-tail-1, I am aware of that. Without singling out any particular engine or aircraft, the point is that it is possible to engineer the electrical back up arrangements such that the risk of an undesirable outcome following, say, alternator failure, is mitigated to an acceptable degree. This is the philosophy on modern jet FADECs, which have no mechanical backups.
I was just picking up on the phrase 'inherently unsuitable', which seems inappropriate given the current state of play with diesels in the marketplace.
Life's a Beech, don't really understand the point you're trying to make. Where does the 30min figure come from? Are you talking about the DA40 or 42, or something else?
I was just picking up on the phrase 'inherently unsuitable', which seems inappropriate given the current state of play with diesels in the marketplace.
Life's a Beech, don't really understand the point you're trying to make. Where does the 30min figure come from? Are you talking about the DA40 or 42, or something else?
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Jellybean. It is indeed a question of what is an acceptable undesirable outcome. So would you take someone flying in an aeroplane which will become a glider within 30 mins of an alternator failure?
Thats assuming you off-load non essential electrical loads quickly enough to conserve your batteries. To go back to a time when engines could be expected to stop because of a simple electrical failure is not progress, and it is not safe.
If you can read French, the discussion on the Gazailes forum is very much to the point. There have been one or two close shaves with electronic diesels, and now the general feeling is that mechanical injection is essential. Some are even retrofitting mechanical fuel systems to modern engines.
Diesels are,( or should be) RELIABLE as well as economical, and with long life.
Thats assuming you off-load non essential electrical loads quickly enough to conserve your batteries. To go back to a time when engines could be expected to stop because of a simple electrical failure is not progress, and it is not safe.
If you can read French, the discussion on the Gazailes forum is very much to the point. There have been one or two close shaves with electronic diesels, and now the general feeling is that mechanical injection is essential. Some are even retrofitting mechanical fuel systems to modern engines.
Diesels are,( or should be) RELIABLE as well as economical, and with long life.
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Originally Posted by vee-tail-1
soay. Please keep up with progress, particularly in France.
The Dieselis, has a mechanical Isuzu turbo-diesel, the Gaz-ailes has a mechanical Citroen AX 1.4 diesel. Jodels like the Delvion and other models use a variety of mechanical diesel engines, from Citroen, Peugeot, and Toyota.
http://gazaile2.free.fr & http://delvion.free.fr
The Dieselis, has a mechanical Isuzu turbo-diesel, the Gaz-ailes has a mechanical Citroen AX 1.4 diesel. Jodels like the Delvion and other models use a variety of mechanical diesel engines, from Citroen, Peugeot, and Toyota.
http://gazaile2.free.fr & http://delvion.free.fr