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News, facts, and comments on the coming revolution for piston-engine aircraft.News of January 07, 2009Thielert Aircraft Engines, the biggest manufacturer of aero diesels, accomplishes turnaroundThe insolvency administrator of aircraft engine manufacturer 'Thielert Aircraft Engines GmbH' (TAE), Bruno M. Kuebler, struck a positive balance for the year 2008. After filing for insolvency in April 2008, the company has accomplished a turnaround and is now back in the black. Additionally, despite insolvency, Kuebler did not have to dismiss a single employee. 'The fact that TAE was able to make it back into the profit zone again without any staff cuts is especially gratifying, particularly in these financially difficult times', emphasized Kuebler. Kuebler continues to negotiate with potential investors. 'Negotiations are progressing with all deliberate speed. New prospective investors have come forward during the past few weeks, so it will still take some time to wind up the negotiations.' The prospective investors are predominantly from the aviation industry and include two defense contractors. According to Kuebler, it is especially important for the latter that TAE is able to develop new military applications for the engines and obtain the necessary certifications as quickly as possible. Kuebler stressed that he is not pressed for time with regard to the negotiations and that it is important to him that the prospective investors offer a sustained solution for the company. Since last October, technical advances with regard to the engines have made it possible to reduce prices for spare parts and servicing again. Moreover, the company was able to extend intervals for servicing of parts subject to regular wear and tear. 'Being able to present this first intermediate result to customers was very important', explained internationally renowned engine expert Prof. Guenter Kappler, who was recruited by Kuebler and functions as the accountable manager in relationship to aviation authorities. 'We know that we must continue to cut operating expenses and are striving intensely to make the engines even more efficient', reports Kappler. Although production faltered briefly after the start of insolvency, TAE is now working to capacity again and supplies engines and parts worldwide to customers in the general aviation sector as well as engines for reconnaissance drones. Thielert Aircraft Engines GmbH is the leading provider of certified kerosene piston aircraft engines for general aviation. As a certified development, manufacturing and maintenance aviation enterprise, the company was the first in the world to be approved for a kerosene piston engine. posted at 8:58 AM News of December 30, 2008SMA continues development of diesel engine
 French engine manufacturer SMA continues to pursue development of its aviation diesel engine SR 305-230. Alain Pierre Deniau, Senior Vice President of the SMA subsidiary in the USA recently stated at the AOPA Expo: ”Both the EU as well as the American legislator are continuously tightening exhaust regulations. This means the end of avgas sooner rather than later.” SMA is absolutely confident that its diesel engine - which runs on Jet-A fuel - will produce lower exhaust gas and noise emissions than current aviation powerplants of this class. The latest improvements of the SR 305-230 encompass twin exhaust gas driven turbochargers, a new intercooler, as well as improved cooling due to optimized engine ventilation. In addition the starter and the alternator were renewed and the cylinder heads were overhauled. SMA is continuing to diligently collect field data. Currently there are 44 engines of type SR 305-230 in operation. No incident implicating the engine has been reported. The oldest of them has accumulated 763 flight hours. A TBO, however, has not yet been defined. For the achievement of type certificates and supplemental type certificates (STCs) for installation of the SMA diesel in further aircraft types including the Cessna 182, Maule-9 and various Piper models the manufacturer is continuing the cooperation with its partners. Potential candidates for the installation of this powerplant are basically all single and twin-engine aircraft with engine ratings between 200 and 700 hp, according to Deniau. posted at 11:22 AM News of December 10, 2008Introducing the CMD GF56 Diesel Engine for General Aviation
 CMD is an Italian firm active in design engineering services for the marine, automotive and general aviation applications of internal combustion engines using all fuels including diesel. See: www.cmdengine.com. It is also manufacturing parts and components, and the range of FNM marine diesel engines. Some engines are based on FIAT blocks and some other are the marine version of FIAT engines (e.g. FIAT 1.3 Multijet for marine applications). CMD developed two aero engines: the GF56 and the ULM 220. The ULM 220 is a 4-cylinder gasoline air-cooled engine of 2.2 liters and 106 kW developed for light aircraft (ULM and VLA). In 2000, CMD initiated design for an innovative aeronautical diesel engine. GF56 has been designed and developed by CMD in cooperation with major Italian universities, the National Research Center and the Italian Aerospace Research Center (CIRA). CMD started the certification process of GF56 on February 2008 CMD sending application in EASA for DOA and engine TC. The first Type Certificate Board Meeting with the selected EASA Team members has been held on May 15th, 2008. This meeting formally signed the starting point of the certification process. GF56 is now accomplishing the development tests in order to freeze the engine configuration for the prototypes dedicated to the certification tests, which will begin in 2009 within a new plant dedicated to the aviation programs. Flight tests will also be performed. The GF56 main natural market is retrofitting existing airplanes. Its engine mount is designed to be compatible with the attachment points of Cirrus aircraft. Main features are: 6 cylinders horizontally opposed. Direct drive-Bore x stroke 106x105mm-Total displacement 5.56 liter. Power 300 HP at 2400 rpm. Power-to-weight ratio of 1 kg/kW. 2-stroke Diesel uniflow cycle. Roots supercharging system with integrated wastegate valve. Liquid cooling. Capable of using automotive diesel fuel or Jet A1. Injection by high pressure Common Rail system. Low piston speed (reduced rpm speed). Low MAP (Mean Effective Pressure). Two camshafts (no long rods), timing with cascade gears. Modular cylinders enclosed in one integral rigid and light semi engine block allowing easy development of a series of engines from 2 to 8 cylinders. Cylinder barrels and cylinder heads form a unique integrated element called “cartridge”. Cartridges and crankcase are held together with studs. A high pressure injection pump is mounted at rear of the engine. It feeds the common rail that distributes the fuel to the electro-injectors located on each cylinder-head via steel fuel lines located on top of the engine. Contact: Mariano Landi, Head of Airworthiness, Technical Department, C.M.D. Costruzioni Motori Diesel, Direzione Generale (Head Office) Strada Statale 87, km 23.300 - 81020 S. Nicola La Strada (CE) – Italy. Tel: +39-0823-424055. Email: mariano.landi@cmdengine.com posted at 11:52 AM News of November 26, 2008Commenting on ExxonMobil decision to decline responsibility when Diesel Aircraft are fueled with Jet-A.As our subscribers know, in a letter sent by ExxonMobil US General Aviation Operations Manager Martin Tippl to distributors of Jet-A fuel on November 17, the company announced it has made the technical decision that ExxonMobil Aviation does not support or endorse the supply of jet fuel to aircraft powered by diesel engines. Included with the letter is an Indemnity Agreement, to be completed by suppliers and returned to ExxonMobil, prohibiting the supply of jet fuel to diesel-powered aircraft and releasing ExxonMobil from any liability in the matter. This is unclear: In other words can the client sign a discharge and refuel at his own risks, or is ExxonMobil directly forbidding suppliers to sell Jet-A to diesel aircraft? ExxonMobil details three technical reasons for its decision: • Ignition Quality- 'The fact that the minimum cetane required to establish airworthiness has not been determined, in combination with the fact that cetane is not measured as part of the jet fuel specification, means that ExxonMobil cannot guarantee the ignition performance of the jet fuel it supplies and cannot know if the aircraft will be airworthy after fueling.' Comment: What is ignition performance in a diesel engine applying spontaneous compression ignition? Does it mean that after all the work done by FAA since the late 90’s in certifying two diesel engines (Thielert and SMA) and after the world’s aviation experience in diesel aircraft going back to the 30’s, ExxonMobil has doubts about ignition taking place or not? Diesel ignition ability is famous for being extremely tolerant to nature of fuel (which doesn’t mean that any fuel can be used, for other reasons.) To pursue. • Freezing Point- 'Unlike turbine powered aircraft, piston powered aircraft do not reach speeds that cause heating of the fuel in the wing due to friction caused by airflow. It is therefore possible that an aircraft powered by a diesel engine could reach altitudes where the fuel would begin to freeze in flight.' Comment: This is a very good point in theory, which was the object of much investigation by FAA and others. Thielert’s answer was that warm excess fuel after combustion is recycled to the wing tanks, thus warming the unused fuel. Thielert on that point was proven right: None of the some 1,000 planes equipped with a Thielert ever reported such freezing incidents. SMA accepted to limit its STC to 12,500 ft until more experience would show that this is definitely a non-issue (182SMAs outside the US regularly fly above 12,500 ft.) • Lubricity- 'Diesel engines rely on the fuel to lubricate key components of the fuel injection system. ExxonMobil Aviation cannot guarantee that the lubricity performance of the jet fuel it supplies will meet the requirements of aviation diesel engines.' Comment: Wrong. Of course a diesel engine doesn’t rely on fuel as lubricant even though diesel fuel does have better lubricating qualities than gasoline. ExxonMobil states that 'until such time as the Federal Aviation Administration and the aviation fuel industry has a clearer idea of the full effects of these issues, the ExxonMobil Aviation position is that diesel powered aircraft should not be fueled with jet fuel.' Both the FAA and the industry having a practice of aero diesels have had a very clear idea of these issues for a long time. The letter using the word 'Until such time as' is where one smells of lawyers pushing ExxonMobil into taking restrictive precautions in fear of… in fear of what? The letter does not expressly state ExxonMobil will refuse to fuel diesel-powered aircraft... but does make clear that customers who insist on being fueled with Jet-A do so at their own risk. Customers insisting upon purchasing jet fuel for their diesel engine aircraft must sign an indemnity agreement before fueling. The letter concludes, 'No fueling of diesel engine aircraft with jet fuel may be performed without a valid indemnity agreement signed by the customer in place.' Comment: We read this as a warning to pilots in the US refueling with ExxonMobil that they should be ready to sign a discharge to the FBO selling the fuel (who is the customer) and forget about it. However there are very few diesel planes flying today in the US: less than 10 182SMAs (reporting zero incidents) and a few dozen DA42 (often grounded for other reasons.) Most aero diesels are flying in other countries. One thing for sure: ExxonMobil is inflicting a blow to Diamond Air, Thielert and also Austro Engine which might be fatal. It will also delay aero diesel in the US until one aircraft manufacturer obtains an STC for a product with a diesel as OEM. Today the next in line is the Maule M9-230 SMA. Our bet is that its certification will be the occasion for reestablishing the truth on this matter. Stay tuned. posted at 6:32 AM News of November 19, 2008A silence making a resounding noise...What is happening on the aero diesel front after so many major news recently? Officially, nothing. Under the surface, we can hear the rumor of major strategic negotiations. Fuel prices, after jumping sky-high (up to $6.70/gallon for Avgas in the US, much higher elsewhere), have come down, but may stabilize at relatively high levels: Petroleum will never be cheap again. Thielert and Diamond are certainly engaged in talks with possible buyers and partners who would help refinance a long term effort bringing to the market a water-cooled, in-line 4-stroke diesel pursuing their previous efforts. The total silence after so much noise indicates that Discovery and Due Diligence are in progress, probably with several negotiations going on at same time. Cirrus, Cessna and probably Piper are certainly reshuffling their long term market forecasts which have been shattered by the world economic recession now gaining in magnitude. The FAA and other international agencies need to address at same time the future of Avgas, the future of the huge fleet of old piston engined planes on the US registrar, and the growing needs of developing countries for economical workhorses in the 250-350HP range addressing urgent but professional applications: rescue, humanitarian, fire service, security, mini cargo, etc. They need to discuss whether Mogas can be finally a suitable alternative to Avgas, that would have some room besides diesels burning Jetfuel. Lycoming and Continental, officially, send 'business as usual' messages and conservative assessments such as: 'The situation is under control... We are preparing the best solutions for fuels available now... There is no need for a revolution, etc. while silently assessing what major innovative engine they will suddenly offer, and with whom. Business jets manufacturers may be wondering what kind of new tax code the new US Administration will impose, which might completely turn upside down the economics of owning a jet. Flight academies around the world must be thinking about the economics of a new generation of trainers offering 2 seats, a 100-120HP diesel and a fuel flow of 3 to 4 gallons/hour. But none of them is certified yet... In that context, which one is the event we are waiting eagerly? It will be Maule Air finally getting its Maule SMA diesel FAA certified. It will be the first market introduction for a certified airplane offering a certified diesel as OEM since the Diamond DA42. It will not amount to much in terms of units per year, but it will mean that there is one diesel engine for which FAA reconfirms an approval after the Thielert/Diamond crisis. It will accelerate many other decisions. posted at 9:36 AM News of October 26, 2008A subscriber asks us to publish the story of his nightmare with his Diamond DA42…David Akel, retired FedEx Airbus Captain (30 years) in Memphis, TN, reports: Over 150 DA-42 (Diamond Twinstar) Owners in the United States are now grounded due to fraudulent concealment and what appears to be corruption on FAA certification of this Daimler Chrysler diesel automotive engine for aircraft use. Some engines did not even last 190 hours on a $600,000 aircraft, with warranty canceled by Thielert and Diamond refusing assistance on the aircraft that they manufactured and sold, and were solely responsible for selecting the defective Thielert 1.7 engines. I signed a purchase order with Premier Aircraft Sales in Ft. Lauderdale for a 2006 Diamond DA-42 on May 14, 2007. Purchase price was $560,000. At the time I was an A-300 Captain for FedEx and was planning on using the DA-42 to supplement my retirement at age 60 in October 2007 by leasing the aircraft to a flight school in Atlanta. Before accepting delivery of a Premier DA-42 demonstrator with 140 hrs, I requested in writing to cancel my purchase due to defective Thielert engines, as evidenced by double flame out and crash, multiple mandatory service bulletins, as well as engine seizures. The request was denied and as per contract I would lose my $56,000 down payment. The first 6 months I averaged a monthly gross of $10,600. Then in April, after performing a service bulletin, a broken piston cooling nozzle was discovered, requiring a replacement engine and grounding the aircraft. A replacement engine was promised to be shipped May 6 2008. However Thielert, the engine manufacturer, declared bankruptcy. Diamond Aircraft Industries executives would not even acknowledge my multiple Fedex requests for help in asking what my options were to get my DA-42 airworthy and back in flight school service, as the bank note, insurance, etc. was $5000/month. This Thielert engine (Centurion 1.7) was certified by the FAA in November of 2004. The engine is a 4 cylinder 135 hp diesel automotive engine made by Daimler Chrysler which Thielert converts for airplane use by adding a gearbox and other aviation specific parts. The FAA approval surprised many industry observers because it entailed producing an engine with parts that the manufacturer (Daimler Chrysler) would not verify. Another FAA first is certification of this engine with 1000 hrs. TBR (To Be Replaced). Diamond quietly started production in late 2005 to replace these defective Thielert 1.7. I also paid $63,000 for the TKS known icing option, which Diamond published as certified for known ice, but it was not certified until March 2008 and only then after performing a Diamond Service Bulletin. Diamond also supplied me with a break even analysis for consideration before purchase showing Thielert 1.7 engine as 2400 hrs TBO with no mention of engine replacement at 1000 hrs. There are 150 DA-42 in USA and most if not all are AOG due to either broken cooling nozzles or cracked cylinder heads. The 2 year warranty on the engines is gone, and any replacement parts or engines are now cost prohibitive as the insolvent Thielert has jacked up the prices 3 to 4 times and will not honor warranty. The dealer has offered nothing but mediation and arbitration as per their contract, and Diamond has offered a customer assistance program with conditions to their ‘valued customers’. If an owner will sign a liability release, then Diamond will put you in the queue for one of their Austro Engines, when it becomes certified. Certification in the US will not be until late 2009, and will require a retrofit STC certification. This will require gutting the aircraft from firewall forward and beefing up the landing gear as the Austro Engine is 84 lbs heavier than Thielert 1.7. Production limitations may push the conversion option to 2010 while your DA-42 sits AOG. However, in return for signing the liability release, Diamond will reimburse their ‘valued customers’ up to 30% of the price of their Austro Engine. DA-42 owners purchased their aircraft from Diamond, and Diamond selected the defective Thielert 1.7 engines for their DA-42. Diamond cannot abdicate responsibility and must cover loss of use as well as the cost of new engines for their DA-42's either out of franchise integrity or by court order. Comment from DieselAir: We are ready to publish answers from Diamond and Thielert… posted at 4:32 AM News of October 12, 2008Thielert bids receivedA savior for diesel propulsion manufacturer Thielert Aircraft Engines may be about to emerge. A spokesman for the German company's administrator says ‘several’ prospective bidders have submitted letters of intent, with "purchase prices within the range the administrator is expecting" a statement on the sale is expected ‘shortly’. A total of 24 potential investors had by late July signed a confidentiality agreement to receive financial details on the company. However, Diamond Aircraft, Thielert's biggest customer and the only general aviation manufacturer to fit its Centurion engine as original equipment, rules out taking over its former supplier. It comes as Austro Engine, the engine maker set up by Diamond, prepares to deliver its two-liter Jet A1-powered AE 300, an alternative to the Centurion. The Austrian company's marketing and sales director Markus Hergeth expects European Aviation Safety Agency certification this month. There are 2,000 Thielert engines powering Diamond s DA40 and DA42 aircraft, retrofitted Pipers and Cessnas, and versions of General Atomics Predator unmanned air vehicle. (By Murdo Morrison, Flight International 9/08) posted at 11:36 AM The forgotten secret of the superb German diesel flying boats.
 (Dornier 26 - Doc: HistoricAircraft.org) Between 1930 and 1945, flying boats for transport were fashionable because the world was lacking runways, especially big runways for big planes. A flying boat doesn’t need a runway. So the jetset of the days was travelling in Boeing 314s, Martin 130, Sikorsky S-40, 42 and 44, Liore-Olivier 24 and 26, Short Calcuttas and Empires… Germany built many flying boats for various uses, most of them using the Junkers Jumo 205 diesel 2-stroke opposite pistons, with powers from 600 to 880 HP. Best knowns were the Do-18 twin, and the Blohm & Voss Ha 138 and 139. The most beautiful, and possibly the most beautiful flying boat ever made, was the Do-26 See Adler (Sea Eagle), which could carry 4 passengers plus crew of 4 and mail from Lisbon to New York, or during the war Bathurst to Natal, and back. During the battle of Narvik in early 1940 Do-26s were carrying 18 troops from Germany to northern Norway. The Do-26 weighed 25,000 Lbs empty and 50,000 Lbs at take off, therefore she could carry her own weight: So much for those who think that diesels are heavy… Top speed was 185 kts. Cruise economy speed was 135 kts and range was almost 4,000 NM. And this leads me to disclose the secret of these diesel flying boats. You certainly agree that the power a plane needs at best economy speed is much less than the power at take off. How much less depends on the design. The most economical plane would be the glider if it could glide for ever, which is why the most economical planes, and therefore the ones with the longest range, are the ones with a high aspect ratio (ratio of wing length to width) giving them a lower induced drag and a most efficient gliding ratio. A classical example was the Convair B36 strategic bomber of the fifties, which had an aspect ratio of 13 and could cruise at 230 kts for 9,000NM without bombs (ferry range). Its six R-4360 engines were delivering 1,000HP at cruise speed against 3,500 at take off. Therefore, to obtain a long range, basically you need a high aspect ratio, and an optimal cruise speed of some 1.3 to 1.5 times stalling speed clean. And here comes the problem with gasoline engines: at 1/3rd to 1/4th their nominal power, the specific fuel consumption (fuel consumed per HP-hour) becomes lousy because combustion is no more in optimal conditions. At same fractional power, the diesel is as efficient as at full power. So maintaining cruise speed may require down to 50% of the fuel flow needed with gasoline engines operating at same fractional power, meaning so much more range. The Germans therefore said: the future of air transportation is the diesel flying boat flying at some 1.3 to 1.5 Va with a high aspect ratio. And they demonstrated it. Then, in 1945, the secret was lost. Nobody was interested anymore in such planes when one could buy a surplus DC3 or DC4 for a song, and use all the runways built during WWII, and when the future so obviously was the turbojet. But today? A cargo diesel motor glider with a very high aspect ratio cruising around 100 kts could very well again be the most effective way to ship goods by air. Eventually, a very big one. Think about it while looking at the plane here under: Do you recognize it?  (Doc. www.ussr-airspace.com)
posted at 8:36 AM News of October 06, 2008Of diesel versus gasoline fuels...We answer here a question from a reader, question which we read quite regularly, and comes from incorrect information about what is a diesel engine: Q: I've been reading about the advantages that diesel will bring to general aviation. We can extract more energy from one gallon of diesel than one gallon of avgas, they are expected to be FADEC, turbo normalized, as well as a few other items. Lycoming just came out with the iE2 electronic engine which they say in the future will be able to burn Avgas, Auto fuel, and heavy fuels (diesel and Jet A I'm assuming). But I have two questions. A: You are right that diesel extracts more energy from one gallon of jetfuel than a gasoline engine from one gallon of Avgas. This is due to higher efficiency in terms of how much mechanical energy is extracted from thermochemical energy available. But this is not the sole advantage of diesel by far. I think that the first advantage is the almost constant specific fuel consumption (Lbs of fuel per HP-hour) which allows extending the range dramatically when reducing speed in an emergency. See our previous papers on this. I do not expect the new Lycoming to burn diesel fuel as well as gasoline. Q1. There are after market FADECs for my continental engine that can be installed by GAMI and Aerostance. Is that all that is needed to switch to Mogas or Diesel. A. Absolutely not. To switch from any kind of gasoline to diesel you need to replace your engine/engine mount/heat exchangers/propeller/engine instruments combine by a completely new one including a diesel engine. Q2: If the new engines can use Diesel or Jet A, but are not used in a diesel cycle engine, do you know if I can still get the extended range using Diesel fuel as oppose to Avgas. A. A diesel engine can only be used in a diesel cycle. It means: Compression ignition (no plugs, no magnetos...), very high compression ratio. And it can only use a diesel fuel such as motordiesel, JetA, or biodiesel fuel. posted at 3:58 AM News of September 26, 2008Look at this photograph and guess how high the 182SMA is flying.
 The Argentinian owner of a Cessna 182 converted to the SMA turbodiesel engine sends us this photograph taken as he is crossing the Andes. One can wonder where he would land if he lost his engine. Guess how high the plane is flying? posted at 8:40 AM News of September 07, 2008Maule is happy with the SMA diesel - 16 SMAs are flying in the US.Brent Maule, sales manager of Georgia-based Maule Air Inc., proclaimed the SMA JetA-powered Maule M9-230 to be ‘the best one that we build’ after making the long cross-country flight from Georgia to Oshkosh in it. 'It was extremely smooth and quiet at 2,200 rpm,' he said, noting it yielded 135 knots consistently. SMA President Luc Pelon said that 16 SMA SR305-230 engines are flying in the United States since their 2006 certification, and 50 worldwide. He made a point of stating that the 230-hp engine burns JetA which, he said, is ‘fast becoming the new avgas’ - probably truer of Europe than the United States, so far. ‘Moving quickly is not our focus,’ Pelon said. ‘We did not make the easiest choice or the inexpensive way when we decided, some years ago, to go to a new engine design from scratch. Instead of trying to use a technology which existed for other applications we started from the ground up.’ The ‘smooth and quiet’ SMA diesel speaks for itself, according to Maule. For more information: MauleAirInc.com or SMAEngines.com. posted at 11:41 AM News of September 04, 2008DeltaHawk signs with FAA a PSCP aiming at diesel engine certification.
 DeltaHawk Engines, Inc. is pleased to announce the formal signing of the Project Specific Certification Plan (PSCP) on August 12th at DeltaHawk facility in Racine., WI. The PSCP is the official document between the FAA and DeltaHawk detailing the specifics of the certification plan along with timelines for completion. This event marks a major milestone in the certification the DeltaHawk V-4 aerodiesel engine. Pictured, standing in front of DeltaHawk’s Cessna 337, are, from left to right: Doug Doers, DH VP of Engineering, Wayne Shade, DH Contract DER, Dean May, DH Certification Project Manager, Christina Liepins, DH A&P Mechanic & Purchasing, Dennis Webb, DH President; Diane Doers, DH CEO, Tim Smythe, FAA Senior Aviation Safety Engineer, Dr. Chung-Der Young, FAA Aerospace Engineer, and Dom DeCosta, DH Contract DAR. posted at 11:13 PM In 2008, four major events are causing a shock in the aero diesel market – DieselAir special review, Chapter 2: The Engineering Arena.
 Scroll down and see Chapter 1 dated July 9. Aero-News says (7/28/08): The 170 hp AE 300 engine incorporates a number of key advancements over the Thielert engine, including an improved gearbox with a torsional vibration damper instead of a friction clutch, designed to offer gearbox life of 2,400 hours. A new, four-point engine mount is also featured, as is an improved turbocharger and a FADEC-controlled, but otherwise conventional engine governor. The Austro engine also sports an integral oil/ coolant heat exchanger, eliminating external oil lines and the need for an external oil cooler. This leaves open some questions: One is we still do not know the weight incidence on a DA 42 of replacing the Thielert 2 Liter by the Austro. But more generally how will an engine rated at 85HP per Liter of Cubic Capacity behave in terms of wear and tear? Keep in mind that a conventional Avgas engine such as Lycoming or Continental is rated around 30-35HP per Liter, and an SMA diesel, at 50HP per Liter. Now, a power close to 100HP per Liter is nothing exceptional in itself. In the fifties, for instance, an Alfa-Romeo Alfetta Formula One 1.5 Liter, supercharged, was delivering 300HP per Liter! But it was expected to last only a few hours. Today, many European and Japanese automobiles have diesel engines rated between 70 and 90 HP/Liter, and they easily exceed 100,000 miles, corresponding to a TBR of well over 3,000 hours. But they do not drive at a constant speed of 125 mph, at which their full power is needed. The two key differences between an airplane engine and an automobile engine are: First, when you are flying in IMC on your way to an alternate, you cannot stop on the safety lane to open the hood and check what is wrong with your engine and then wait for Triple-A service. Second, an aero engine must be light. To make it lighter, you remove metal volume, and refrigerant volume meaning accordingly circulating oil or water. The lighter it is, the more vulnerable it becomes to thermal shocks, and each of these shocks increases the wear and tear. Adding fifty pounds of weight to an auto engine is not that bad, even though it comes to sense that the life expectancy of a 5 Liter V8 is higher than the one of a 4 cylinder 750cc engine. But to an aero engine, less weight is critical. So far, the Thielert saga has proven the point of the old timers saying that you can’t beat cubic inches when it comes to reliability. Does it mean that they are right? Not necessarily. If your engine is using state of the art technology for alloys and even more for surface treatments, the fact is that the reliability has incredibly increased compared with the 40s and 50s when your Lycoming and Continental were state of the art, and that the experts in these technologies are in Europe. It made sense to expect that the most sophisticated European R&Ds in automobile engine knew how to make a small aero engine that would last longer than expected, whether diesel or gasoline. Thielert comes from the race car engine profession. The SMA team originated with Renault Sports who was designing the famous Renault V10 Formula One engine. Mark Wilksch, founder of Wilksch Airmotive, came from the famous Cosworth team. These three firms, coming from same background, opted for three different solutions: In-line, water cooled, 4 cylinder, 4 stroke, high rpm geared engine, high power per Liter (Thielert, Austro); Opposite piston, air cooled, 4 stroke, no gear, medium power per Liter (SMA); V design, 2 stroke, no gear, medium power (Wilksch). And we can assume they had access to the same know how in terms of alloys, surface treatments, techniques for vibration control, for fuel injection, heat exchange, exhaust design, etc. Why did they disagree on design? And who is right? I have one explanation: Any engineer in automobile engine design owns a car, drives around, maintains it, pays for it, and tinkers with it. Very few of these same engineers own and operate an airplane and live in everyday life how dramatic must be, on any aircraft cruising close to full power, the zero defect, zero incident, trouble-free factor, down to the most modest hose, seal, connector, bearing, and bolt. Therefore these Europeans, lacking that background, began trying different solutions, each one in his neck of the woods. Who is right? Time will tell, but it looks like LSA diesel engines of 100-120HP will be 2 stroke, that so far Thielert has caused a setback to the high rpm in-line geared engine, that Austro has not yet clearly explained why they will do radically better than Thielert, and that SMA, as of now the only FAA certified and world certified engine that seems to run trouble free, does not have yet enough engines actually flying to take advantage of the situation. posted at 9:52 PM News of August 06, 2008LoPresti Announces ‘Innovation In Aviation’ Award
 LoPresti Aviation announced on Saturday at EAA AirVenture that they have established a new annual award for ‘Innovation in Aviation,’ in honor of their founder, aircraft designer Roy LoPresti. The first winner, DeltaHawk Engines, is a small company that has worked for 12 years to bring a new diesel design to the market. ‘The persistence and creativity of this company is something of which Roy would have approved,’ the company said in a news release. LoPresti will work with the winners to help develop and market their ideas. The award will be presented every year at Oshkosh. ‘In this next year you will see their engine gain certification and we will work with them to create STC's for the burgeoning diesel market,’ LoPresti said. See: http://www.avweb.com/newspics/loprestiaward.jpg (Avweb 8/4/08) posted at 12:32 PM News of August 01, 2008Battle over diesels moves to Oshkosh
 The Austro-German battle of the diesels moved its venue to Oshkosh this week, but the combatants remained restrained and on best behavior even though they were only a few yards apart. AirVenture marked the first public static showing of the 168 hp Austro Engine AE 300 liquid cooled diesel being developed by Diamond Aircraft to replace the Thielert Aircraft Engines power plants used by some of the Diamond models until Thielert s insolvency earlier this year. Since then the supply of Thielert diesels to Diamond has ceased, crippling delivery of Diamond aircraft and leading to a very public and spiteful war of words between Thielert s liquidation administrator Dr. Bruno Kuebler and Diamond Aircraft owner and CEO Christian Dries. Austro Engine is aiming for EASA certification this fall. Its new facility aims to produce 2,000 engines a year to power Diamond Aircraft’s DA40, DA42 and DA50. Both the Austro and the Thielert designs are based on Mercedes A-class four-cylinder engines, but the AE 300 substitutes some heavier cast iron parts for the aluminum used by Thielert. Austro Engine is a consortium between Diamond Aircraft, MBtech in Germany, and other partners. Diamond had planned to switch to its own engine from Thielert anyway, but the Thielert bankruptcy has advanced the timing. Austro engines are currently being test flown extensively in the three Diamond models. Thielert, though in liquidation, displayed its Centurion engines at AirVenture. Why would a bankrupt company bother to exhibit, one might ask? Thielert sales manager Jasper Wolffson was assuring all comers that production of spare parts is continuing while more than 50 would-be investors assess taking over the ailing company. ‘We hope to have a new owner by the end of September,’ he told Aviation Week. While Diamond has claimed that more than 72 Diamonds are grounded around the world for lack of Thielert parts and more than 40 are stored at the factory without engines, Wolffson insists that the groundings are not his company’s fault. Parts are available, he says. But under German law Kübler canceled all warranties on Thielert engines in the field. At the same time he significantly raised the price of parts that operators now had to pay for parts, and told Diamond they must pay in advance for engines at a far higher price than had previously been agreed. The real issue is the gearbox and clutch on the Thielert diesel engine, which must be replaced every 300 hours at a cost (for just the parts) of 5,000 euros. Thielert had promised the first exchange for free under warranty up to 600 hours; now the warranty is canceled owners must pay, and though they can file a claim with the liquidator they are likely to receive back ‘anything from zero to 100%,’ said Wolffson. Many are choosing to wait; meanwhile their aircraft remain grounded. Wolffson allowed that the Thielert marketing strategy had been one of not being too expensive, and of encouraging operators to overlook the shortfalls of the gearbox. Now the liquidator is trying to put Thielert on a viable commercial footing before selling the company. Thielert is facing the loss of its major customer as it moves toward new ownership (some 2,500 engines are in service, mostly on Diamonds), but Wolffson said talks are continuing with Cessna on a regular basis on supplying engines for a diesel Cessna 172. Cessna, though, is holding back until it can check the pedigree of the new owners. Meanwhile the Thielert development department has actually grown during the insolvency, charged primarily with extending the life of that gearbox and clutch. ‘It would be wrong to say it is business as usual, but we are at Oshkosh to show that we are still alive,’ said Wolffson. ‘We are very, very optimistic.’ (Aviation Week 8/1/08) posted at 12:44 PM |
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