DA40-NG comparrison to DA40-XLS

[HPNAviator]

Now that it looks like Diamond will be selling the Austro powered DA40-NG in the USA does anybody have a side by side analysis of the pros of cons of each model. I understand the value in Europe for the Jet-A powered model but would there by advantage in the USA especially for those of us that live in the east coast with no high mountains to traverse or hot and high airports to depart from.

[Colin]

I really love the idea of FADEC, but I would be very nervous having it running my sole piston engine.

[CFIDave]

I really love the idea of FADEC, but I would be very nervous having it running my sole piston engine.

When's the last time you drove a car with a choke or mixture control? Most of us don't even think about the fact that our car engines have been computerized "FADEC" for the last 20-30 years, and they seem more reliable than piston airplane engines.

When you climb back into a Lycoming DA40 and make use of all those arcane techniques for managing CHTs, EGTs, RPMs, and mixture, it really makes you appreciate flying FADEC engines.

[CFIDave]

does anybody have a side by side analysis of the pros of cons of each model.

DA40NG (Austro Engine) Advantages:
- Smoother, quieter engine reduces pilot/passenger fatigue
- Better fuel economy (fewer gph fuel burn + cheaper JetA fuel)
- FADEC eliminates mixture and prop control
- No hot starts, no cold starts, no need to pre-heat in the winter -- the engine always fires up right away with just a simple turn of the key.
- No worries about shock cooling (due to liquid-cooled engine) from "slam dunk" approaches.
- Less opportunity for CO poisoning, since heat is produced from hot coolant rather than from a shroud around a potentially leaky engine exhaust
- No potential for fouled spark plugs (there aren't any!)
- Turbocharged diesel engine makes more power with better climb rate and faster airspeeds above 3000 feet, provides higher service ceiling.
- Oil changes every 100 hours instead of every 50 hours, very little need to "top off" engine oil between oil changes
- Austro engine overhaul is cheaper than Lycoming engine overhaul (although TBO so far is only 1800 instead of 2000 hours), so hourly engine reserve may not be much different.
- Available with integrated factory air conditioning that doesn't hurt performance (as opposed to Lycoming DA40s with air conditioning that require draggy belly scoop).
- Reduced wingspan with vertical winglets fits better into a 40-foot wide hangar.

DA40XLS/XLT (Lycoming Engine) Advantages:
- Lower stall speed improves safety for both normal and forced landings
- Shorter takeoff and landing distances
- Aircraft is at least $60,000 less expensive to purchase
- Greater useful load
- Engine is more powerful with better climb rate below 3000 feet
- Cheaper oil changes (no need to buy expensive 100-hour Austro engine kit from Diamond and special diesel engine oil/gearbox oil; instead purchase cheap oil and filter from multiple sources)
- More (most) aircraft maintenance shops know how to work on Lycoming engines, particularly in the US
- Nicer interior with more/better leather

[rwtucker]

I really love the idea of FADEC, but I would be very nervous having it running my sole piston engine.

When's the last time you drove a car with a choke or mixture control? Most of us don't even think about the fact that our car engines have been computerized "FADEC" for the last 20-30 years, and they seem more reliable than piston airplane engines. When you climb back into a DA40 and make use of all those arcane techniques for managing CHTs, EGTs, RPMs, and mixture, it really makes you appreciate flying FADEC engines.

I get that Dave but haven't you DA42 owners made quite a few postings about failures somewhere in the FADEC chain?

You are right, automotive FADEC is fantastic. In fact, many brands of automobiles have become essentially failure free. I have bought, driven, and sold quite a few ECM automobiles since the 1980's and have never replaced anything but tires and batteries. The same is true for integrated automotive electronics. But automotive isn't much of a comparison with GA. In spite of (or maybe because of) the tight regulation and "quality control" mechanisms, GA design and manufacturing is of overall lower quality than general automotive. I think our Diamonds are among the best GA has to offer but put several hundred hours on one and you start seeing sensors fail, oil leak, alternators seize, powerplants and airframes corrode, switches break, avionics fail, etc. GA can't even make a fuel valve switch that doesn't start leaking sometime in the first few thousand hours. Overall, GA production seems rooted in the 1960's with a patchwork of modern avionics not built to especially high standards.

Given all this, if Honda or Lexus were to design FADEC for my powerplant, I would be an early adopter. If Lycoming designs it, I would worry. I'm not so sure about Austro. It seems like there are a lot more posts here on FADEC related DA42 engine problems than there are on old-fashioned hand-choked DA40 engines.

[Antoine]

Stephen: Dave's list is spot on (except for one point if I may: XLS is the better performer in real world) - The NG has more drag than a midsize lorry and the XLS more horsepower than the official 180 on its TC!

I suggest you go fly both and see for yourself. Here's why:
A few months ago, I bumped into a friendly french pilot who was about to purchase a DA40 NG (steam-gauge TDI with NG retrofit - marketed in France).
He asked me to take him for a test ride in my 2007 DA40-180.
I accepted and let him try whatever he wanted (except slamming the throttle closed as he had done in the NG - be nice to my Lycosaur!). He did slow flight, stalls, engine idle best glides, speed runs, economy runs, steep turns, full power climbs and loved the plane. We remained in contact since then.
He has bought none of them so far (for other reasons) but much preferred the -180.

Now to my personal opinion:
I apologize for being so crude, but I positively hate the DA40 NG from the day I saw one and I feel compelled to state it loud and clear. Sadly, the plane has started to deliver on its scary characteristics.
This overweight, out-of-balance, ugly thing is killing students and instructors in Russia in stall/spin accidents. I know of 2 such events, so far, both fatal.
Stall/spin in a DA40?

[CFIDave]

It seems like there are a lot more posts here on FADEC related DA42 engine problems than there are on old-fashioned hand-choked DA40 engines.

Part of the reason you may hear about DA42 owners with FADEC problems is that computerized systems are really good at detecting and reporting faults, even those that are minor or intermittent.

In contrast, if you have a Lycoming engine with dirty or fouled plugs, a faulty or worn mag, bad ignition timing, a partially clogged fuel injector, unstable idle, etc., the engine can't explicitly tell you if or when something is wrong -- you the pilot have to detect the problem. There are multiple Lycoming DA40s I've flown where the owner or flight school (or even mechanics right after an annual inspection or pre-buy) were unaware of engine problems that hadn't been addressed.

For that reason I'd rather take my chances with a FADEC-controlled engine. At least for Austro engines, I'm not aware of any in-flight engine stoppages except for those caused by human error (e.g., turning off the engine master switch by mistake). An Austro engine with an "ECU fail" message will still keep on running -- this is no different from computerized car engines that continue to run at somewhat reduced power when the "check engine" light comes on.

[rwtucker]

It seems like there are a lot more posts here on FADEC related DA42 engine problems than there are on old-fashioned hand-choked DA40 engines.

Part of the reason you may hear about DA42 owners with FADEC problems is that computerized systems are really good at detecting and reporting faults, even those that are minor or intermittent. In contrast, if you have a Lycoming engine with dirty or fouled plugs, a faulty or worn mag, bad ignition timing, a partially clogged fuel injector, unstable idle, etc., the engine can't explicitly tell you if or when something is wrong -- you the pilot have to detect the problem. There are multiple Lycoming DA40s I've flown where the owner or flight school (or even mechanics right after an annual inspection or pre-buy) were unaware of engine problems that hadn't been addressed.

All very good points Dave.

I had to laugh, though, your list of things we have to look out for in GA makes my main point. I don't know how many hundreds of thousands of miles I and my family have racked up on ECM auto engines, but I do know the fouled plug count, the clogged fuel injector count, the bad timing count, the unstable idle count, the engine stopping count, the engine running rough count, the bad electronic ignition count, and the "did anything at all ever go wrong with the engine count." I forgot. There is the wheel bearings pack count, the exhaust mounts freeze if you don't lube them constantly count, the cut my oil filter and look for broken pieces of engine count, and a bunch more. The grand total of all of these counts is zero. How long do you think it will take, or what revolution will have to take place, before we are able to purchase aircraft that are as reliable as a Lexus?

[CFIDave]

How long do you think it will take, or what revolution will have to take place, before we are able to purchase aircraft that are as reliable as a Lexus?

The answer unfortunately, is probably "never."

The secret of automotive-style reliability is statistical quality control applied to very large numbers of produced autos. That's what turned "made in Japan" products from junk, to today's Lexus-level of reliability. Auto manufacturers around the world have all adopted these same quality control techniques.

Unfortunately due to the tiny number of GA piston aircraft produced per year (about 1000), there's no way to apply statistical quality controls. Instead, GA has become a boutique industry with very small numbers of hand-crafted aircraft, engines, and components. We're lucky that GA aircraft work as well as they do.

However to the extent that GA manufacturers can re-purpose automotive products for aircraft use, they may be able to benefit from automotive levels of quality. A good example is Austro Engines use of actual Mercedes car engines for the core of their AE300 engines (installed in the DA40NG). Because over 1 million of these engines have been produced by Mercedes for their cars, the core engines should prove to be extremely reliable. The challenge for Diamond/Austro is to achieve similar levels of reliability for their gearboxes, ECUs, engine sensors, turbochargers, radiators, and other components that are "add-ons" to the Mercedes engine cores.

[Tommy]

For all the reasons stated by Antoine, I will probably never get any airplane that is diesel.
Oh, by the way Antoine, you missed the initial price premium that you pay for a diesel that will be passed down or at least attempted when the plane is sold in the after market.