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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.News of September 06, 2005Special report: A fruitful dialogue between Aviation Consumer and DieselAirNewletter.Paul Bertorelli, Editor in Chief, Aviation Consumer, sent an answer to our August 18 discussion of the Aviation Consumer special report on the coming of aero-diesels. This opened an email exchange. Patrick Canivet, CEO of FlyJetA who sells Cessna 182 SMA conversions, added his comments. We summarize or quote here what was said. (Remark: these exchanges took place before Katrina.) We thank Paul and Patrick for their time. Paul Bertorelli (Aviation Consumer): In the U.S. market, diesels will live or die on how buyers react to them and thus far, the reaction has been lukewarm. Our surveys indicate strong interest in diesel technology but thus far, few owners willing to translate that interest into sales. Our most recent survey in the June issue indicated that the high cost of diesel market entry is one reason for this. (We surveyed more than 800 people, worldwide.) Yet, our conclusion was: "Although the diesels are a non-starter for U.S. conversions, the cost curves clearly favor them in the long run, as fuel prices rise. Thielert and other diesel makers need only wait for the right timing." I have recently test flown the SMA-powered Cessna 182. The cost of this conversion is currently right around $90,000, give or take. The cost of top-notch overhaul for the O-470 which the diesel replaces is about $25,000. So for the diesel's benefits, the owner will be spending something like $55,000 to $65,000 more than he would for an overhauled gasoline engine. And what are the benefits? As measured by us, the airplane climbs better, say 900 FPM versus 600 FPM at altitudes above 6000 feet. Because of the diesel's excess cooling drag, its cruise speed is about the same as the gasoline engine version, and gets a little better at higher altitudes: SMA claims 140 knots TAS versus 136 knots for gasoline version at 12,500 ft. According to the SMA POH, the fuel burn difference is 9 GPH for the diesel, and 11.1 GPH for the gasoline engine. SMA tells us the fuel Delta is much more favorable to the diesel than the POH allows but because they have not flown us in an airplane equipped with a fuel flow meter, we cannot confirm the claims. Full fuel payload is reduced by about 110 pounds: In the SMA diesel version, empty weight rises by about 40 to 50 pounds. Then, equivalent-range payload offsets this somewhat. For example, if the diesel airplane is loaded with 50 gallons of fuel, it can carry about 765 pounds of additional load. For the same fuel amount, the gasoline airplane can carry 850 pounds of additional load. The diesel can fly about 750 miles to dry tanks on this fuel load while the gasoline version can fly 600 miles. However, that extra 50 pounds the gas version can carry translates to another 8 gallons of fuel or 140 miles. So the two engines are very close in down-fueled range performance. In terms of full-fuel range, the diesel has a clear advantage: 1,300 miles total range versus 1,070 miles for the gas, both to dry tanks. The diesel enjoys an altitude advantage and will climb over weather that the gasoline version will have to fly through. This offers a clear advantage over the gasoline engine version. Where we disagree is that the diesel is thus a "vastly superior" airplane. It is not. It has some advantages and some disadvantages. Having those advantages will cost a potential buyer as much as $60,000 or more; half the value of the airplane itself. European buyers are already driven by fuel cost considerations. American buyers aren’t yet, although they may be in the short-term future. For a private owner flying 150 hours a year, the fuel savings of operating a diesel might come to $1,200 a year. It simply makes little sense to spend $60,000 or more to save $1200. That's less than half the interest you could earn in a modestly successful investment. You do get better climb, range and altitude performance. But these are incremental improvements to the airplane, not transformational improvements worthy of a $60,000 investment. Very few owners actually want or need to fly in the teens to avoid weather or fly non-stop for 900 miles. It's just not a common profile for the airplane to fly. Commercial operators can do better with a diesel in the U.S. market, on fuel savings alone. But they'll still need to make the investment. In the U.S. currently, there are few if any service centers for diesel engines and there may not be for at least a year or two. Our view is the market encroachment of diesels is inevitable, given the economics of fuel prices. They make sense and probably will endure. But it's too early and we are advising readers to wait before making this investment. We don't agree that the rise in value of a diesel engine airplane is a sure thing and we don't think owners should bet $60,000 on that particular farm. A year or two from now, maybe. But not yet. You may publish this response, if you wish. I would respectfully request you steer your readers to our extensive diesel coverage in the June, August and October 2005 issues. Let them judge for themselves what we have to say. Andre Teissier-duCros (DieselAir Newsletter): What you said published very faithfully the opinion today of some 800 pilots. Aviation Consumer must base its opinions on what is available and proven today, while DieselAir Newsletter tries to forecast where diesel is going 2, 5, 10 years from now and why. We think that what a 182 owner gets for some $90,000 (or a 172 owner will, with a Thielert) is much, much more than an engine: New cowl, new engine instruments and controls, new 3-blade propeller, added heat exchangers, new engine mount, with possibility to negotiate in the price new avionics, new paint, new interior and a corrosion inspection. Suppose his plane is worth $60,000 initially, he can find himself with a better than new plane for much less than the price of a new 182. We being in the rational crystal ball business claim that the market value of this converted plane will, after that, go up as a consequence of extended Mission Ability and Safety. As for fuel consumption, I agree with 9 GPH for the 182SMA which I also tested. My 182Q, at same speed, does 13 GPH. So do all the five 182Q's which I know well at PDK Airport. For long distance cruises (Ex: Atlanta-Long Island NY), I cannot fly at full cruise speed if I want legal reserves when I get there. So in practical conditions the 182 SMA diesel as proposed today would be faster on such a long leg by some 20K (say 135 against 115). It will be even faster 2 years from now, because we are talking only of what SMA proposes now, which is very limited in order to humor conditions required by FAA for an STC as early as possible. The SMA engine is a 300HP engine down-rated to 230HP, and down-rated further in altitude to facilitate initial specs allowing an early STC. Embry-Riddle has experienced 153K with such a plane, ignoring these provisional specs. Someone who buys the plane today will have access to future engine retuning’s (including revised cowl) as FAA accepts, based on experience, loosened specs. He will fly higher, and faster. (The same is true, by the way, for owners of 172 Thielert.) An Avgas 182Q - such as mine - has a capacity of 88 gallons usable, a useful load of 2,950-1,770 = 1,180 Lbs. Payload, as is, is 650 Lbs with full tanks. If converted to SMA, the same capacity plus extra load will mean: Useful load 2,950 - 1,210 = 1,140 Lbs. Jetfuel is 10% heavier so payload is down to 1,140 - (88 G. x 6.6 Lbs) = 559 Lbs. This is still ample for my most frequent mission of 4.5 to 6 hours from PDK, alone or with one passenger. (During the 500 hours I flew with that plane, we carried 4 people only once). But I will fly faster to NY (see above), without fear of running out of gas when I get in the Washington-Baltimore-NewYork airspace with constant rerouting calls: "7GA, ready to copy?" .(The New York ATC gets very impatient if a modest 182 answers: "minimal fuel..."!) I never fly to dry tanks. I fly IFR and plan for 3 hours reserves: legal IFR reserve, plus alternate, plus taking into account I am 68 years old. Also my 182Q will not fly close to 1,070 NM to dry tanks...! Therefore my experienced figures become: With my 182 as is: Avgas with 3 hours reserves: 670NM at 115-120 Knots. With the 182 SMA Jetfuel, same reserves: either 674 NM at 136 Knots (much faster), or 1,275 NM at 115 Knots. Because here comes the beauty: the constant specific consumption of the diesel means that, if you slow down, Gallons/hour drop much more than with a gasoline engine (well known by taxi drivers fighting traffic jams all around the world). If for any reason I am below minimums at destination and alternate and am down to 10 gallons of fuel at cruise speed, if I slow down to 82 Knots, my fuel consumption goes down to 3.5 gallons/h, I can still fly some 240 NM, and my engine still runs like a clock. (This is why I say that, for practical purposes, a diesel plane can fly almost for ever...) You will notice that, in my demonstration, I didn't even bother to mention fuel costs. For me, it's only a cherry on top. All US pilots and professionals are obsessed with amortizing a diesel thanks to fuel savings alone. Here we agree: fuel savings alone will never justify the conversion even with Avgas at $8.-/Gallon (which will come). Also, the 182 SMA happens not to be the best example because the 182 already has a relatively long range. A 172 diesel is even more convincing because, with 40 gallons, the 172 Avgas simply cannot fulfill a serious IFR cross country mission. A 172 diesel does. Here, it is a question of can't do/can do. Same for a Piper Warrior. I agree that most pilots of today do not fly a 182 for 600NM with 3 hours reserves. But it happens to be my profile: I learned to fly at age 59, have 900+ hours, and presently fly 120h/Yr. mostly for business, often IFR, visiting clients in the boonies. I live in Thunderstorm Alley, where flying above the weather is a plus. And when diesels come, there will be many new pilots and new aircraft owners who will learn to fly, and fly my kind of missions. I expect AOPA to become aware of it, and use it to promote GA: "With diesel and GPS, beat the airlines and travel for less." Also I consider being free of the fear of engine fire and of engine loss as important. So, we agree to wait for two years... except some pilots who will want to be smart and be among the first ones. And we predict a real culture shock when the 300-350HP diesels become available for twins which fly 1,000 hours/Yr. and will see their market value jump. Which is another story. N. B. My figures for Range as function of Speed, specific consumption and other parameters come from a Computer Model we developed for our own use. Patrick Canivet (FlyJetA): Comparing prices: The SMA should be compared to a gasoline engine of 230HP of similar power with Turbo and Fadec. If it existed (also meaning no carb heat, no manifold pressure to adjust, no mixture control), it would be priced anew around $35,000 against some 49,000 for a new SMA with a complete kit. But at TBO, a Cessna 182SMA will pay no more than the TBO price of a regular O-540. Also, servicing costs go down in proportion to the number of engine parts: We are comparing a diesel with 500 parts and an O-540 or O-470 with 2,500 parts. Preventive maintenance is very simple: No magneto, no distribution, and no spark plugs. The rest is easy visual inspection. Any job requiring disassembling the engine (changing a cylinder, or a piston) will require, for an already certified A&P, a simple training program in situ or in a SMA facility. Working on the SMA will be more like servicing a lawnmower engine than a Porsche engine. posted at 10:44 AM |
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