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When will a diesel be available for my aircraft? |
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News, facts, and comments on the coming revolution for piston-engine aircraft.
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News of April 20, 2012The shape of things to come… A leg with sea crossing of 760 NM with a 53HP diesel 2-seater in 7:28 hours. 101 knots average, with 14.8 gallons or 1.97 gallons/hour.
    Serge comments : On his next design he will use a 2012 state-of-the-art Peugeot. T/O power is 80 HP for a weight only slightly higher, and his computations allow him to seriously forecast a cruise speed of 135knots with a fuel flow of 2.02 gph. Lets think ahead: Best known diesel airplanes were originally designed for a gasoline engine, whether they are retrofitted used planes such as the 172 Centurion or the 182 SMA, or new planes originally designed for an Avgas engine and modified to be OEM’d with diesel. Serge Pennec designed the Gazaile from scratch around the Peugeot diesel engine… which was designed itself as an automobile engine. The vast majority of diesel airplanes use the Centurion (ex-Thielert) engine and some begin using the Austro 300 engine which are not automobile engines, but have been derived from an automobile design. If I forecast what could be a true state-of-the-art diesel airplane, designed around a true aero diesel engine and using diesel to fit a mission where the best advantages of that engine technology are put to use, I see a buckled-wing airplane (demonstrated by the SwAT prototype) stalling at 16 knots and cruising at 160 knots with a glide slope of 40. I see a swash-plate barrel diesel engine capable of an SFC of 0.25 Lbs of JetA per HP-hour.  (photographs by permission of Serge Pennec and L. L. Ballot.) posted at 5:56 AM News of March 04, 2012Will Steyr Motors be the first one introducing a 300HP aero diesel?Many readers ask me when shall we finally see a certified 300HP+ aero diesel on the market, able to equip a Cessna 206, A Bonanza, a Mirage, a Cirrus SR22 and even possibly a helicopter? We know that it will take several years. Until now, possible contenders seemed Centurion and SMA Engines, although none of them has the resources to complete this development now. Two other serious firms now seem able to beat them. Various announcements from Diamond Air, Steyr Motors and Austro Engines indicate that they jointly attempt to develop a redesigned marine Steyr Monoblock Motor into a 280HP 6-cylinder engine and later a 440HP engine. The other actor is TEOS Powertrain Engineering, a joint venture of two French manufacturing firms well known in race cars and aviation engines: Mecachrome, and D2T Powertrain. TEOS undertakes developments in diesel, gasoline and hybrid powerdrives for aviation and other markets. Eurocopter, the world leader in helicopters and a subsidiary of the EADS Group, is following closely both developments, and regularly confirms interest in a diesel helico, even though projects take more time than expected. A few months ago, EADS Chief Technical Officer Jean Botti was quoted by Aviation Week saying that the engine for the demonstrator already has been chosen, but said little more beyond that it will weigh around 550 pounds and deliver 300 kw of power while burning about 220 grams – 0.07 gal. – per kilowatt hour. The goal is to cut fuel consumption by 40% below that of a comparable turbine-powered helicopter, had said Olivier Jouis, Eurocopter’s director of environmental matters. However, cutting fuel consumption by 40% is vague: Compared to what? To another aero diesel?> To a gasoline engine? Jouis acknowledged in Aviation Week report that there are plenty of technical challenges to be overcome. Getting the tolerances right for airborne applications is “not trivial,” he pointed out, nor is design of the reduction gear, which will have to endure the stresses associated with the torque and vibration of a piston diesel engine. Jouis said that the engine will have “more than eight cylinders” to minimize the vibration and torque stresses. Meanwhile, France-based turboshaft specialist Turbomeca has shelved its plans for such an engine. One thing is sure: Helicos are working tools which fly a lot, and which are hampered by their turboprop engine in terms of SFC. Turboshafts are very compact. Their power-to-weight ratio is very favorable. However, their fuel consumption is high. For relatively small power requirements, a diesel engine is much better from that standpoint. Any diesel would allow helicopters longer and more flexible missions, if the weight is right and if the vibrations can be kept in check. So, the helico market might play a major role in activating the birth of the certified diesel of more than 300HP. Stay tuned as usual! posted at 12:37 PM News of January 22, 2012What is the most significant event in the world arena of aero diesel?What is the most significant event in the world arena of aero diesel? The most significant event is that Centurion-Thielert has not only survived, but progressed. I confess that 2 years ago I had doubts about the firm’s future - no more a going concern, filing the German equivalent of Chapter 11 - and about the technology of its engine: In-line, liquid cooled, geared with a high rpm, rather heavy, a spotty record of reliability and of customer satisfaction, etc. Yet, since then the firm made a systematic, methodical effort in retesting, redesigning and improving one by one its core components and its procedures for manufacturing and quality control, in the classical German way. The new feedback from customers became by late 2010: The engine is costly (compared with a classical Avgas O-360 why you can buy for a song…), it must be maintained right, but it works. Well, as of early 2012, the 2 liter Centurion remains by very far the leader on the tiny market of aero diesels while none of its competitors has made tangible progress in actual sales, certifications, and market share. Now the firm reports making progress in extending the lifetime of engines and components, which is the most important for the customer. STCs for the 155hp Centurion 2.0s are progressing: Centurion offers this engine for the single-engined Diamond DA40 since end of November '11. I asked Centurion if they had any news of their interesting V8 4-liter 300HP engine, which got its TC before bankruptcy and has been running notably on a few Cessna 206s. There were also talks at the time of a 230HP 6-cyl. Centurion answered: Most development sources are needed for the Centurion 2.0 and 2.0s to extend lifetime of engines and parts. Regarding the 4.0, we already have the TC for the engine and the STC for Cessna 206 and Cirrus SR22. Right now, development projects run as ordered from customers. Regarding a 6 cylinder there is currently no running project due to the fact this is smallest share of the market. The company has been run under insolvency proceeding conditions now for nearly 4 years which is not unusual under German law. As long as we remain at stage of negotiations with potential investors, the company invests comparably lower development budgets than in past times. A future investor or OEM partner may change this situation. Conclusion: Centurion is alive and kicking, has a modest but positive cash flow, is improving its product, and looks more and more like the lonely success story so far in the arena. posted at 5:57 AM News of January 08, 2012We have found the breakthrough in diesel concepts. It burns at most 110 grams (0.26 Lbs.) of fuel per HP-hour. (2)You remember that, on September 15, we asked in DieselAir the question: “If a 5,000 HP diesel engine can burn no more than 0.22 Lbs of fuel per HP-h, while weighing no more than 0.18 kg per HP dry, it will trigger new concepts for air travel and cargo in 2050.” See http://www.dieselair.com/2011/09/fanjet-airplane-will-never-be-effective.html We told you before Xmas that we received lots of answers. And yes, we did identify an R&D firm proposing an innovative concept: It is FairDiesel Co., Ltd. in the UK. You can visualize their concept by going to http://www.fairdiesel.co.uk/. The stockholders of FairDiesel now have two opportunity searches in progress: One aims at an equity investment from a venture capital or other business financing partner; one aims at a joint venture with a manufacturing firm already in the industry of engines, motors and other complex components for aircraft. The consulting firm exclusively retained to expose all details of the proposed combination is TARGON Investments (Offices in Houston, Shanghai, Montpellier). All inquiries should be addressed at bgrierson@preternatural.net We restate here that the FairDiesel engine promises, on well founded grounds, for an engine of 5,000HP, a Specific Fuel Consumption (SFC) between 100 and 110 grams/HP-h and a weight of less than 1 metric tonne (2,200 Lbs.). The inventor, Bill Fairney, and his advisers, have an impressive engineering background in internal combustion technology. FairDiesel showed us that these figures are demonstrated with a computer model applying accepted laws of mechanics, thermodynamics, heat generation from Jetfuel as available, heat conductivity & transfer, friction & lubrication, etc., to a totally innovative concept. This concept, however, can be applied to manufacturing an engine using conventional available metals and alloys, assembled with parts which are cast, machined and eventually heat-treated using conventional, inexpensive technology. There is no need, for these parts, of ceramics (except for one coating), or cermets, or composites and other materials which are inherently costly to manufacture. The concept has also been simulated for powers of 2,500; 550; and 275 HP. Specific Fuel Consumption (SFC) doesn’t change. Weight per HP gets of course higher for smaller engines. Nevertheless, around 250-300 HP, the weight per power ratio is much more favorable than for any opposite cylinder gasoline engine such as O-470, 520, 540 or 550. Also you can easily appreciate by looking at the structure and kinematics of the FairDiesel that it is virtually vibration-free. Its torque will be constant within a large spectrum of rpms. Which is why its promoters assess that its application for helicopters is also very promising. Andre Teissier-duCros posted at 3:53 PM News of December 16, 2011Precision and correction regarding ownership of Continental Motors.Ms. Gloria Liu, Business Analyst with Continental, commenting on our latest information on the aero diesel arena, asked us to clarify that Continental Motors Inc. (CMI) was acquired by AVIC International, not by CAIGA. CAIGA (China Aviation Industry General Aircraft Co., Ltd.) is the company that merged with Cirrus Aircraft. Ultimately AVIC International and CAIGA are related companies as part of a larger conglomerate, but CMI is a direct subsidiary of AVIC. posted at 12:22 PM News of December 12, 2011We have found the breakthrough in diesel concepts. It burns at most 110 grams (0.26 Lbs.) of fuel per HP-hour.On September 15, we asked in DieselAir the question: “If a 5,000 HP diesel engine can burn no more than 0.22 Lbs of fuel per HP-h, while weighing no more than 0.18 kg per HP dry, it will trigger new concepts for air travel and cargo in 2050.” See http://www.dieselair.com/2011/09/fanjet-airplane-will-never-be-effective.html We received lots of answers, and we thank our subscribers for their help. And yes, we did identify an R&D firm proposing an innovative concept. It promises, on well founded grounds, for an engine of 5,000HP, a Specific Fuel Consumption (SFC) between 100 and 110 grams/HP-h and a weight of less than 1 metric tonne (2,200 Lbs.). The inventor and his advisers have an impressive engineering background in internal combustion technology. These figures are demonstrated with a computer model applying accepted laws of mechanics, thermodynamics, heat generation from Jetfuel as is available, heat conductivity & transfer, friction & lubrication, etc., to a totally innovative concept. This concept, however, can be applied to manufacturing an engine using conventional available metals and alloys, assembled with parts which are cast, machined and eventually heat-treated using conventional, inexpensive technology. There is no need, for these parts, of ceramics, or cermets, or composites and other materials which are inherently costly to manufacture. The power of 5,000 HP was chosen because it fits with a large market of 4-engined commuters and of air cargos. However this concept has also been simulated for powers of 2,500; 550; and 275 HP. SFC doesn’t change. Weight per HP gets of course higher for smaller engines. Nevertheless, around 250-300 HP, the weight per power ratio is much more favorable than for any opposite cylinder gasoline engine such as O-470, 520, 540 or 550. The stockholders of the firm which developed the concept tell us that, because of pending no-shopping agreements, they are bound to keep a low profile now but will be free to make a public announcement by January 1st, 2012.They agreed to give then DieselAir an exclusivity for this scoop. Meanwhile anyone wishing an early, private disclosure is invited to inform them by email to bgrierson@preternatural.net. So stay tuned, and in the mean time, prepare to enjoy Christmas and the season’s holidays! Andre Teissier-duCros posted at 12:58 PM News of November 23, 2011Of Avgas, geopolitics and common sense.It seems clear today that any airplane pilot in the US who owns any type of piston-engined airplane presently burning 100LL will not be able anytime soon simply to refill it with a new Avgas that would be entirely lead-free. And as an observer, since 1998, of the coming of diesel engines burning JetA and available to replace Avgas or other gasoline-burning aircraft, I know that diesel engines replacing any existing gasoline engine on existing aircraft are no more on the horizon either. This newsletter expressed such hopes a few years ago for the Cessna 172 and 182 and for the Piper PA28 and later for others. They are gone at least for the US. As for new, FAA certified airplanes (other than Experimentals) sold with a diesel as OEM, the only models available on the US market and worldwide are made by Diamond Air from Austria, and the only other one available outside the US is the French-built Finch Ecoflyer, which is based on the Robin DR400 equipped with a Centurion diesel. That’s all. Looking back, I can see that, in recent years, the major events affecting the future of both 100LL and aero diesel have been the acquisition by China Aviation Industry General Aircraft Co. (CAIGA) of Continental engines from Teledyne, with the publicly expressed intention to develop Continental’s aero diesel technology purchased from SMA, and the decision of the Chinese administration to ban 100LL as aviation fuel. So, 30 years from now, the future Chinese owners of small airplanes will burn Jetfuel, plus non leaded gasoline. 30 years from now! Note that there are today some 1,000 piston-engined planes on the Chinese register… In 2042, you might have 100,000 of them. Now, the huge world fleet of piston-engined airplanes (around 300,000) consists in majority (200,000+) of planes on the US register, of advanced age (38 years old in average), which are not flying much (say, less than 50 hours/year). The average age of their pilots and owners is above 50. It was easy before 2008 to assess that whether one considers the market of such planes, or the market of spare parts and services for them, or the market of their engines, or the market of 100LL, the special fuel they burn, we were looking at a tiny, mature, depressed market, with no hope for revival. And since 2008, the assessment has gone worse. The gods with a deep pocket running the planet today viewed Teledyne’s decision to sell Continental to CAIGA for a measly 189 million as wise: Get out of here while the going is good. Let’s quietly sell or wrap down all US businesses whose product or service depends on piston-engined planes. ‘Will the last person leaving this facility and this town please turn the lights off.’ (Seattle during Boeing’s bad days,1971.) Yet, there is one law of life and of business which I have always verified since I began my professional life back in the sixties: It is called Euripides’ Law. Euripides, a Greek philosopher, wrote in 500 B. C.: “It is never the worst, but the unexpected that eventually happens.” My qualified assessment which I publish for discussions is this: The US industry dedicated to the smaller, piston-engined, plane, and its components, services and consumables is by far dominant in the world. It is highly competitive. It is represented mostly by small and midsize businesses who know how to move fast. Its costs are relatively low, and getting lower with a weak dollar and a weak economy. It is traditionally dedicated to its domestic market, but is ready to work for the devil, if the devil wants a small plane and is ready to pay. And the devil in our case exists: It is the overseas market of professionals of all kinds who, for either of the 6,000 reasons not elsewhere classified, need to fly a small inexpensive plane, fueled with a basic fuel available anywhere, and fly relatively intensively. Their number is growing. But it happens to be growing much faster in several world regions, and not in the U. S. Comments are welcome at info@dieselair.com. posted at 12:34 AM News of October 31, 2011This diesel airplane has an automobile engine which is not geared… Now read these performances!The Delvion DVD is a 3-seater light plane made in France, which has accumulated several years of tests and seems to be flying in the hands of a few enlightened owners. It is derived from the old and excellent family of Jodel light airplanes, best known of which is the Robin DR400.   Reminder: The very first Jodel airplane, called in the fifties the “Bebe Jodel” (baby), was a single seat plane using a 60 c. i. VW Beetle engine of 32HP, so the experience in adapting an auto engine to a plane is old for all designers who were associated with Jean Delemontez, the design engineer at the origin of the Jodel-Robin designs. Our third photo shows one Bebe Jodel among the multitude flying today.  posted at 1:31 PM News of October 03, 2011More automobile diesel engines converted to LSA applications open new lines of thought.Two of our subscribers, Paul Lucas in Europe and Chas Kenny in New Zealand, sent me reports on interesting conversions of an LSA with an automobile diesel. The Isuzu 1.5 liter, 67HP, indirect injection, is the engine of the Opel Corsa among other cars. Lucas reports a 700 h flying experience from 1988 to 2000 on the Dieselis, see http://membres.multimania.fr/dieselis/, an LSA equipped with this engine. At take off the engine delivers 67HP at 3,600 rpm. At cruise, it needs only 26 HP at 2,800 rpm and consumes then 6liters/h, or 1.6 USG, while flying at 90 Kts. Of course as with all diesels the sole control is the throttle. Lucas says the engine has a very high torque. Because of the high compression ratio, the propeller becomes a strong air brake at low settings and the throttle then also acts as a simple control of the sink rate during approaches. I recently wrote that an engine of less than 100HP seemed of limited interest for an LSA. Lucas contradicts me, rightly it seems, saying such an engine is very suitable. He says: ‘You can purchase it at your local automotive dealer, new or second hand. It is a well proven engine, with millions of units produced, and spare parts everywhere. Water cooling is a standard and efficient device: every automotive engine builder has dropped the air cooling. A diesel needs a very efficient cooling and constant temperature. With an air cooling, you restrict the flight domain: impossible to climb at high angle (too hot), impossible to descend at high angle (too cold), especially with a clean machine, gliding at an L/D of 15. We installed a cogbelt (timing belt) reduction drive, and it worked.’ Is it too heavy? Lucas says: ‘Every one said that before the first flight. In fact the propeller efficiency (thanks to large torque, large prop diameter, slim engine cowling) is quite better than usual. We got 1000 ft/min with two aboard, on a plane which weighs 800Lbs empty. And this was with a heavy engine (cast iron block) and a wood and fabric wing. Conclusion: 60 to 80 hp is quite sufficient for a good LSA.’ I would add: Yes, if it is a diesel… Lucas then raises an interesting point regarding weight and cooling: the water cooling airframe integration. In the Thielert approach, he says, the radiator is under the engine cowling, which leads to low cooling efficiency and more drag, because of too small a radiator and poor ducting. For better efficiency, one needs a large radiator located aft, and long inlet and outlet ductings, same as on the P51 Mustang. Advantage: the aft cooling weight helps balancing the heavier engine. But this layout needs too much room to be installed in front of the firewall. Lucas concludes: ‘We have to design new aircrafts to cope with those new diesel engines.’ Chas Kenny reports from down under: ‘I flew a Jodel D9 for many years. When Jean Delemontez drew the D18, it sparked my interest in building a homebuilt again. The only other Jodels in New Zealand were the popular D11. But having a farming background I always appreciated a good diesel engine and wanted to fly one. The Peugeot 1.9 liter diesel was new in NZ around that time. I worked my own Peugeot conversion design out of a Jodel D150 airframe design. After much of the airframe was built I discovered Delvion, A diesel Jodel using the same engine with a direct drive, no gear, by Jean Delemontez and Jacques Vion in France. While based on a bigger airframe the good news was that it worked. The radiator is in the wing like the DH Mosquito, and the Oddessy battery is in the left wing. They are mounted in what would have been cuff fuel tanks in the D150. The 43013 wing section gives plenty of room. This section as used on later Jodel / Robin aircraft will help me get off the ground earlier. The engine is in a bed mount and has had the injection pump overhauled and the fueling set for max fueling at 2000 / 3300 RPM. A short exhaust allows the turbo to spool up quicker. Being direct drive the drive axle is driven through a Centaflex LF22 coupling. All has worked out to an engine system weighing around 300 Lbs. The inlet manifold and intercooler will be placed below the cowl line. During the next weekend it will taxi for the first time. While all seems good my conversion is not yet proven. If it goes as well as Delvion D103, or even as well as my old D9 I will be happy.’ Meanwhile the Delvion is flying in Europe. I got messages that Diesel Jet Srl in Italy is demonstrating a Fiat-based aero diesel which just got EASA certified. It is a 4-cyl., 1.9 lit. liquid cooled engine, 8 valves, with turbocharger, FADEC and Common Rail injection. Remarks and Questions: All these engines weigh around 300 Lbs for powers of 80 to 100HP, which is very heavy. The Thielert-Centurion has the same weight, but delivers 155HP because so much more development work has been done that the engine has nothing in common with its Mercedes-Benz ancestor besides the engine block arrangement. Incidentally the Finch Aircraft Ecoflyer, also designed on the proven DR400 design ex from Jodel, sells with a Thielert 155HP and seems to give a lot of satisfaction. This is an occasion to remind all that what matters when comparing performance of diesel versus gasoline engine is not the sole engine weight, but the weight of engine plus maximal fuel. An LSA doesn’t need a long range since it is limited by regulations to local flying. Neither does a 2-seat trainer for flight academies. So they can fly with a tank all the smaller that fuel consumption is low. Also room becomes available in the wings for batteries and cooling system as the Delvion illustrates. On bigger planes, the weight handicap of diesel diminishes with power: Thus the SMA diesel 4-cylinder of 230HP, installed on a 182, weighs slightly more than the original O-470 and the same as an O-540. Only 4 samples of the Thielert V8-300 HP became operational (on Cessna 206s) until Thielert’s bankruptcy compelled the firm to suspend development, but one could observe that the engine weight was close to the weight of the airplanes’ original 300HP 6-cylinders. Forecasting work we undertake at DieselAir with our panelists show that aero diesels of powers in the 300-500 HPOur subscribers who have experiences with flying a Delvion, or similar conversions of an automobile diesel of any power above 65 HP and available for Experimentals, are welcome to send me a report, with photographs. As one could expect, automobile diesels are heavy for aviation use, especially with powers of less then 250HP. But if the airframe design can accommodate the engine and two passengers, and if the engine has a torque good enough at low rpms to dispense with a gear, considering that a long range is not requested and the fuel tank can be small, the main advantages remain: A plane that uses Jet A and is not dependent on 100LL (or VLL which has only 19% less lead therefore doesn’t have a long term future), which is highly economical, and very safe. And then, availability of some cheap spare parts from a mass-produced auto engine, plus doing away with an expensive gear transmission makes a lot of sense for LSAs. As for using a timing belt gear, this is very economical and feasible if you respect a short TBR… and do not plan to cross 500 miles of sea. posted at 2:16 PM News of September 15, 2011A fanjet airplane will never be effective when flying low or slow. Yet, with future energy costs, that is how many future airplanes may have to fly.If a 5,000 HP diesel engine can burn no more than 0.22 Lbs of fuel per HP-h, while weighing no more than 0.18 kg. /HP dry, it will trigger new concepts for air travel and cargo in 2050. Our panelists say it can be done. DieselAir engages research here on a Special Report. Are you working on an innovative diesel concept which could reach such performance? Now read this. What follows here is public information. Conclusions we made are our own. Fact: According to UN, world population will stabilize around 11 - 12 billion people by 2100. Until then, we know that the price per kWh of any kind of energy, whether mineral, renewable, nuclear, syn-organic, or bio-organic, computed in hours of average salary, will go way up, same as the price of virtually all commodities. And I mean way up. Fact: A Boeing, Airbus, Bombardier, or Embraer airliner is based on an aircraft concept originating in the late 40’s: Swept-wing, all-metal jet plane, flying above the weather, fast enough to cross the Atlantic non-stop in a few hours. It was far more productive in terms of passenger-miles per year than a DC7C, the most advanced piston-engined airliner of the fifties. Fuel efficiency was a factor only insofar as it affected range and payload, as always in aircraft technology. Petroleum availability was not an issue. Emissions and noise control were minor issues. Fact: The ancestor of this concept is the Boeing 707, first truly successful jet airliner, origin of a large family of airplane models, of the Airbus family sticking to the same concept, and then some others. In 1954 when the 707 prototype first flew, gold price was $35 an ounce and petroleum was $1 a barrel. Now the figures are $2,000 and $80. Average salaries followed, of course, until the 90’s. That’s over now. And the real crisis is only beginning… By 1960, the turbojet engine was the obvious future: It is very efficient at stabilized, high altitude cruise speed. It is a gas-guzzler in-between, during transitional phases of taxiing, take off, climb, hold, descent and approach, land, which meant one had to use IT, Navaids and good management to minimize these phases in the leg. And the longer the leg, the less they mattered. Since the fifties, IT and Navaids made momentous progress. Hub airports were favored to take advantage of jumbo jets flying legs of up to 15 hours today, packed with low-fare passengers complaining about clogged lavatories after 10 hours… Fact: The efficiency of the turbojet itself also made progress: A 1944 Junkers Jumo 004B turbojet equipping a Messerschmitt 262 fighter jet had a specific fuel consumption when cruising (never for very long) of 1.6 kg per kg of thrust and per hour, with a TBO of 20 hours if the pilot was lucky. Now a CFM turbofan and its state of the art competitors achieve 0.35 kg. And the next generation might do 8 to 12% less. The jet airliner concept triggered, from the sixties onwards, an explosion of air transportation not only for passengers but also for air cargo. Cost per passenger-mile and per tonne-mile has been going regularly down from the Douglas DC3 of 1935 to the Airbus 380 and Boeing 787 of today. It looked as if it might go on for ever… Well, this is not true anymore. The whole industry engaged in designing the airliners for the 2040-2090 era, their engines and components, are questioning the concept because the turbojet cannot be efficient when flying low or slow, whereas absolute energy need per tonne-mile is always lower at low speeds. I say energy need, not fuel consumption. The most effective motor gliders, with glide slopes of 40, cruise around 120-140 Kts. See example at http://www.skykingsoaring.com/motorglider.html. If you seek even lower energy needs, look at the Solar Impulse weighing 1.6 tonne which cruises – very slow - with photovoltaic-generated 40 HP, see http://www.solarimpulse.com/. The most obvious reasons are oil and gas prices and availability; energy costs escalation in general; environment concerns, among others CO2 emissions; and a world crisis affecting the whole world’s purchasing power. But IT and Internet are another, as they make fast business travel less necessary. Changes in life style are another: Why go through the stress and discomfort of commuting to crowded airports, going through 2-hour security checks, being packed for hours in narrow seats, fighting to get your luggage, and again commuting, etc., when on top of that airline fares will go way up? Couldn’t one at least go non-stop to final destination, even if in a smaller, slower but roomier plane, since more and more smaller airports get equipped to host at least the commuters of today? As for air cargo, it uses Boeing 777 and Airbus A330 and the like because they happen to be available. Nobody said that parcels had to fly as fast as 400 knots if it is no more economical? What about the propeller? When the fantastically successful Lockheed C130 Hercules military cargo first took off in 1954 (yes, same as the 707), its design team would never have anticipated that, 60 years later, the new Airbus A400M of similar mission would look like a bigger Hercules, still with 4 propellers, but more efficient ones of course, giving it a top speed of 375 knots. The propeller is alive and kicking. So is it time to consider a new concept? What could it be? There may be one: A diesel-equipped airplane, if the diesel could be at least as efficient as a turbofan at cruise speed, and of comparable weight per power. The obvious advantage of a diesel, if it was efficient enough at cruise speed, results of its constant specific consumption at any speed and during all transitions, which means that when flying slow, therefore using a low power setting, the fuel consumption stays practically in proportion of the actual power consumed, therefore drops to extremely low figures when the plane flies close to best range speed, typically 1.5 times stalling speed. So that minimal energy need does translate into minimal fuel per mile. A cargo plane could be a large, unmanned moto-glider tracking a route negotiated in real time between a GPS and a weather report to get to destination at lowest cost per mile instead of at imposed speed and time of arrival, while taking advantage of best meteo conditions (tail wind, soaring…) It wouldn’t do for a passenger plane, but one could simply imagine larger, roomier but slower planes flying above the weather during cruise, same as a jet, but capable of very economical flights when the same optimizing system would navigate during transitions. Now let’s benchmark: The turbofan of a state of the art 2011 airliner, assuming a cruising speed of 430 knots (800 km/h), is consuming around 120 grams (0.26 Lbs) of fuel per HP-hour. A heavy marine diesel 2-stroke of some 20,000 to 100,000 HP (MAN or Wartsila-Sulzer) also achieves 120 grams. But its very high weight per HP makes it suitable only for stationery or marine applications. An aero diesel piston-engine, such as the ones on the market or close to (Centurion-Thielert, SMA, Austro, DeltaHawk…), achieves around 155-160 grams per HP-hour. But the turbofan hasn’t said its last word. The coming P&W1100G (Geared Fan) or the GEC-Safran Leap X might reach around 105-110 grams… These are abstracts from a more detailed benchmarking spreadsheet prepared by our panel of experts. They estimate that a totally innovative diesel concept of around 5,000 HP, promising a Specific Fuel Consumption (SFC) of 100 grams (0.22 Lbs.) per HP-hour for a dry weight of 0.18kgs/HP, is possible, and would allow a breakthrough in terms of average fuel cost per tonne-mile, for a lower capital cost than the turbofan. Of course advantages would be more obvious on short and midrange applications, beginning with commuters. We do not foresee that the turbofan would disappear, but that it would specialize in long range, mass transportation between hubs, for passengers willing to pay the rate. Do you know of a diesel project promising to meet such specs? Better, are you working on one? If you do, alert me at atc@dieselair.com and expect a quick answer. I will send our panelists’ benchmarking spreadsheet to any subscriber requesting it. And we will publish your story. Andre Teissier-duCros, Publisher posted at 7:01 AM News of August 01, 2011Centurion is at AirVenture in Oshkosh and makes an announcement.From July 25 to 31, Centurion Aircraft Engines AG & Co. KG will be presenting its Centurion-series diesel aircraft engines for general aviation aircraft on Booth 98. The company has reported excellent figures regarding the reliability and safety of its engines. The amount of cumulative flight time logged has risen by half a million hours, a figure that shows just how intensively these engines have been operated by Centurion’s loyal customers. The Centurion-series engines stand out thanks to their unique level of fuel efficiency and their reliability. In contrast to the competition, these engines have been developed so that these, having the same weight, can be installed without modifying or replacing the cowlings. It is precisely this fact that makes their use in a variety of manned and unmanned aircraft possible and makes replacing the Centurion 1.7 with the Centurion 2.0 very simple in all aircraft. Both engines have an above-average level of reliability. According to the FAA, engines used in general aviation experience an average of ten engine failures or “in-flight shutdowns” (IFSDs) every 100,000 flight hours. The shutdown rate of Centurion engines is around 50 percent lower and has been reduced even further since the last EAA AirVenture a year ago. Taking the period since its introduction onto the market in 2003 into consideration, the shutdown rate for all Centurion engine models is 5.46 per every 100,000 flight hours. In fact, measured over the last 52 weeks, the shutdown rate of the most recent engine model, the Centurion 2.0, has been just 2.32 IFSDs per 100,000 flight hours, thus being the most reliable piston engine for use in general aviation. Naturally, the Centurion 2.0 possesses various advantages over the 1.7 thanks to all the experience gained from the field with its predecessor. During the same period the cumulative flight time of the Centurion fleet rose by half a million hours to reach 2.7 million hours. “Around 1.36 million of the flight hours account for Centurion 1.7, and with its introduction onto the market in 2002 we encouraged the market to develop alternative propulsion systems for small aircraft and UAVs. Its successors, the serially-produced Centurion 2.0 and the Centurion 2.0s, have generated 1.34 million flight hours to date. Well over 3,000 Centurion engines have already been delivered in total,” explained Centurion CEO Jasper M. Wolffson, who also said: “Centurion engines do not emit any lead, and emissions of nitrogen and hydrocarbons are considerably lower in comparison to avgas engines. Moreover, Centurion engines basically consume less fuel and adhere to strict noise pollution regulations. So they are not affected by the EPA’s initiatives or by lawsuits like those in California. Centurion engines are fit for the future both commercially and ecologically as they can run on standard kerosene-type jet fuel and are not reliant on aviation gasoline or avgas,” Comment: A year ago, one could be skeptical about the future of Thielert GmbH reorganized out of Chapter 11 by Centurion and publicly known to be for sale, finding no buyers. The engine was criticized for its complexity and costly maintenance. Well, it found no buyers so far but the hard fact is that between 98 and 99% of diesel airplanes flying in the world are equipped with their engine, either 1.7 or 2.0 liters, plus a certain amount of Drones. It is clear that the business is a going concern, generating a positive cash flow and able to service customers; and that the planes keep flying. Of course one can expect that it needs funding to pursue further other developments, notably engines of over 300HP where most of the dollar value of the market is. But meanwhile, it is business as usual in Saxony. Centurion will make history in being the first to demonstrate that the aero diesel is viable. posted at 1:40 AM News of June 23, 2011Dennis Webb, CEO of DeltaHawk engines, answers to Bill Brogdon’s interview of June 1st.Dennis Webb writes: I appreciate my good friend Mr. Bill Brogdon’s very favorable comments about the future of diesel aviation, and we at DeltaHawk certainly concur with most of his statements. However, we do need to correct some important points. First, as DeltaHawk’s CEO, I can say with absolute authority that his statement “DeltaHawk was sold to the Chinese” is not accurate. DeltaHawk does have a deep business relationship with Hunan Sunward, an outstanding business partner and a company that will soon be proven to be one of the leaders of General Aviation in China and the world. But DeltaHawk has not been sold to any Chinese or other interests, and remains a North American owned and operated business. Second, we certainly agree with Bill Brogdon’s comments regarding the technical challenges of two-stroke engines, and that is one of the many reasons our development has taken quite a number of years. But we have overcome those technical challenges with proprietary, innovative technology, which will be rolled out to the aviation world as we commence delivery of production engines this year. We have just moved into our new 70,000 square foot headquarters, R&D, and production facility, where we are gearing up for production and continually hiring new staff as we work with the FAA to finalize certification. We are also working on airframe projects with numerous key partners, both civilian and military, that will become production products in the near term. Again, we appreciate Bill’s very positive comments about aviation diesels. We see a very exciting future. Dennis Webb, President and CEO, DeltaHawk Engines, Inc. posted at 5:53 AM News of June 01, 2011Bill Brogdon talks about aero diesels and Continental under Chinese ownership.This is an exclusive interview for DieselAir. Bill recently retired from his position as Teledyne Continental Motors’s Chief Engineer after nearly forty years in design and development of piston engines for aircraft and other applications. He remains active as an engine engineering consultant. Andre: Bill, do you think that the aero diesel engine has a future? Bill: The aero diesel engine definitely has a future. That future will depend largely on economics that are hard to predict; but the aero diesel is the correct... (Click here to read the whole interview.) posted at 1:26 PM News of May 12, 2011Why Diesel? Could the future be an electric plane?
 This is a good question when looking at the Chinese made YUNEEC e430 light plane, which flies 100% on electric power. Yes, same as an electric car, with batteries as sole energy source. The e430 is a comfortable 2 seater. Made of composites, it looks almost like a glider with a serious landing gear and with a butterfly tail, but has a 54HP electric motor activating a conventional propeller. It can stay in the air for 3 hours. The Kokam-made polymer-lithium battery can be recharged on the ground, or quickly replaced. Now lets look at the specs: Empty weight is 295kg and max. weight is 475kg. Not so bad if you keep in mind the battery plus motor weight of 110kg. Climb rate 400ft/mn. Cruise speed 75Kts with stalling speed of 35, so the ratio of max. cruise to stall is only 2.1. With 3 hours autonomy this means at most 200NM without reserves. Conclusion: It is indeed same as an electric car, it wont go fast and it wont go far. But it is silent, clean, and apparently quite pleasant to fly. And it is not expensive. Can it make progress? Again, like with a car, you would need a battery that can store much more energy, and at times deliver this energy at a much higher power. Progress in energy per kg have been very slow since the lead battery was invented in 1850 (yes, 1850, not 1950...) but since then technology has managed to multiply by 5 or 6 the stored Watt-hours per kg. So we can expect that the e430 will have a market as an original LSA. posted at 12:03 PM News of April 17, 2011A new diesel plane with Centurion-Thielert diesel 155HP: The Flight Design C4Germany’s Flight Design unveiled a mock-up of its new, four-seat piston single it is calling the C4. “We want to create the optimal four-seat aircraft for our customers,” said Oliver Reinhardt, chief technical officer. “Engineers often put emphasis on certain features of a new design, while a flight school or a private owner might want something we did  not consider, so we are putting our concept of the C4 design out for the public to participate in the process.” The company is planning to collect as much information as possible from potential customers and from its worldwide dealer network and only then, probably at the next AirVenture, will they decide the final setup of the airplane. After AirVenture Oshkosh, the design will be frozen and the first flying prototype will be shown eight months later at Sun ‘n Fun. European approval is scheduled for late 2012, with U.S. certification to follow soon after. The airplane will be powered by an American (gas) and German (diesel) engine, but several “green” solutions are possible together with the hybrid technology. Comments: Flight Design seems to trust Centurion better than any diesel supplier so far, for an airplane which is promised to a very wide diversified clientele including flight academies if it keeps its promises. posted at 8:59 AM |
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