Why New Aircraft Engine Ideas Rarely Succeed

that's a picture of the best piston engine in general aviation today it's a continental i o 550. best means lots of powers smooth running and economical if anything burning 16 gallons an hour can be thought of as economical in this airplane that's a cirrus sr-22t that's 190 knots at 12 miles per gallon ain't no prius but it goes three times as fast this is a picture of the most sophisticated piston engine in general aviation today the austro-a330 it powers this the diamond da62 twin which according to me is the most refined and well sorted out airplane in general aviation today if you've got 1.2 million diamond will build you one i'd like mine in this metallic red please in a previous video on engine failures lots of viewers suggested that car engines don't work in airplanes or aren't reliable because they can't run that 70 percent power continuously fair point and a common belief but also a myth back to the ae330 this is a car engine a diesel car engine with a few modifications it's straight off the mercedes-benz assembly line it runs at 70 percent power all day for 1800 hours has a full up fedex electronic fuel injection and onboard diagnostic capability so so great why aren't there more of them flying if i toss up one of my annoying pot no hell i'm sick of pie let's use a cake chart continental and lycoming are represented by the two thick layers rotax has the thin layer of frosting in the middle and ostrow is the barely there frosting on the top so what gives here it's a long and bumpy story mostly shaped by industrial and market inertia customers who say they want new sophisticated stuff but really aren't that adventurous and buy new engine ideas that were underfunded or just didn't work that well to begin with but mostly by this undeniable fact it's fun to bash these old aircraft engines as dinosaurs invented in the 1960s but well they actually work for all their foibles everyone knows what they cost how they perform and how reliable they're likely to be so when it's time to write a check for a new engine not too many buyers snag their pants on the lack of dual overhead cams or obd while general aviation isn't exactly cheek by jowl with cutting-edge engines it's not entirely for lack of trying let's start with this engine which if you are a connoisseur of aviation projects that turned into craters you will recognize as the rotax v6 whose marketing name eventually became rev two versions were planned one at 225 horsepower and one at 300. it was announced with great secretive fanfare in 2003 and by 2006 it was just another rusting hulk in the graveyard of aviation dead enders rotax killed it probably rightly this engine should have satisfied the supposed appetite for automotive type high technology it was a v6 with overhead cams fuel injection and electronic ignition all the stuff you'd expect in a modern engine cirrus actually wanted it and had test phone it to replace the continental i o 360 and the sr-20 which was a little underpowered rotax had even invested in a v6 production equipment line at its austrian factory and it was ready to rock so why don't we have v6 powered sr20s good question from what we can tell the answer is that the engine needed more work the basic structural geometry wasn't quite right more investment was needed at the time rotax's canadian mothership that was bombardier had sold off the austrian engine factory and the interest just wasn't there to carry on with the v6 there were probably inside corporate intrigues that we don't know about too but if they had gone forward with it would it have succeeded maybe maybe not an engine project this ambitious needs field technical support and overhaul facilities and above all warranty support at the time rotax already had a reputation in the u.s for not being good at that stuff and mechanics complained about the 900 series engines being difficult to service but they really weren't they were just different what unfolded the following year in 2007 would have shown rotax the sort of bullet it dodged when it abandoned the v-6 at the berlin air show in 2002 when diamond aircraft introduced this the da42 it violated an unwritten rule in airplane design which is it's risky to introduced an untried engine in an untried airframe to be fair the airframe was based on this the da40 single yet it was still a departure but the engine the engine was something else it was a tealert 1.7 centurion an adaptation of the mercedes-benz om-640 diesel mb used in these cars the a-class sedans these were sold in the bazillions with the engine being the beneficiary of millions of euros of development it had all the latest technology dual overhead camshafts four valves per cylinder turbocharging and common rail fuel injection and electronic controls it was about as bulletproof as engines get tilert played quite the contorted word game dissoning itself from mercedes-benz insisting that the centurion wasn't a car engine and that half the parts in the centurion were built by tieler some to lighten it for aircraft use but then the trouble started the airplane itself was well received especially by flight schools who needed twins for the airline market training the da42 was a delight to fly and although it never achieved the aspirational 200 knots the engines were smooth and easy to operate but by 2007 owners were complaining about aog maintenance issues a lot of owners there were problems with cylinder heads cracking piston lubrication pump failures and at least 22 engine stoppages the gearbox was a major headache it was supposed to be removed and inspected every 300 hours and owners said taylor vastly underestimated the labor hours necessary to do that work tealer promised a rapid increase in gearbox intervals but it was years and coming by then taylor was bankrupt there was little fundamentally wrong with the engine its problems were just teething pains the business failed because taylor over-promised on performance and botched warranty response in economics this fiasco very nearly took diamond down with it since angry owners expected diamond to fix engines that tealer couldn't or wouldn't the situation so pissed off this man diamond aircraft founder christian dries that he started his own engine company and that's austro when i visited the austro factory to shoot this video dries pointed to a spanking new mercedes-benz om640 on the factory floor yup the very same one taylor used as the basis for its engine and he said you cannot improve on this and ostrow didn't try they took the engine straight off the bend's assembly line stripped off certain automotive components installed the gearbox and other aviation components and had themselves an engine recently astro has been manufacturing the core engine themselves there's one good reason why the austro-engine should not have succeeded and one good reason why it did austro retained the original mercedes-benz cast iron block which means the engine weighs 112 pounds more than the tiered version did that could be a deal killer especially in a twin where the weight gain is times two a typical airframer would understandably look for a lighter engine but christian dries was providing engines for his own airframes and decided to invest the money to certify both the single and the twin to a higher weight to accommodate the heavier engine before the company failed tealer also tried to market this behemoth the centurion 4.0 it's also a mercedes diesel a turbocharged 32-valve v8 used in the s-class bins these are the ones that blow by you at a buck 50 on the autobahn while the driver puffs on camels at 628 pounds it's 200 pounds heavier than the continental i o 550 for similar horsepower again sears considered it for the sr-22 but like diamond it would have had to re-engineer the airplane for the higher weight doable yes but for what game evidently not much let's look at some numbers to see how that big v8 would have compared to the continental i o 550. it's higher weight means a lower power to weight ratio about 40 percent lower what it loses in power to weight it gains in fuel efficiency the diesel can run at a brake specific fuel consumption of about 0.34 to 0.35 but the io 550 is no slouch either it will operate all day at 0.38 to 0.39 running lean and peak at 70 percent power for both of them that's the difference between 11.8 and 14 gallons per hour so for the equivalent weight of fuel the diesel enjoys a range advantage this has proven out in the real world these graphics show how the austro-diesel in diamonds da40ng provides a slight range advantage over the lycoming version of the same airplane in the u.s jet a for the diesel is about 50 cents cheaper than 100 low lead for the i o 550 so that works out to an 18 dollar an hour advantage it's a bigger advantage in europe where have gas is north of 10 bucks a gallon that ain't chicken feed for sure but it's never been clear to me that a buyer who can afford a nearly million dollar airplane cares that much about fuel prices although some flight schools seem to what was really expected to launch diesel aircraft engines to dominance was the disappearance of 100 low-level ab gas aviation journalists like me have been saying this for 40 years and the damn stuff just won't go away although it's hard to find in some parts of the world but jet a what the diesels burn it's everywhere aircraft diesels have another advantage they're easier to operate ever start an i o five history well you prime it first then get the mixture set crack the throttle not too much crank it fires right up but it doesn't catch so you gotta prime it some more not too much set the throttle hold your mouth just right crank it and it starts right up if the engine is warm there's a procedure to start it that works every time but nobody knows what it is usually it involves starting with the throttle wide open so it scares the hell out of everyone on the ramp when it's really cold you gotta drag a portable furnace out to the airplane and heat it up for 15 minutes yes we're still doing this with the diesel just push the start button if it's really cold turn on the glow plugs for 40 seconds there's no mixture control in the diesels and in the diamonds no prop control either if one engine quits in the twins and you have to cage it right just flip the switch it feathers itself it's kind of amazing to think that 20 years into the 21st century a gasoline-powered twin still has six levers to operate the engines literally a steam locomotive gets by on two the single power lever idea has been the holy grail for at least 40 years and that gets us to another engine idea that looked great on paper the porsche mooney in 1985 these two companies thought buyers would resonate with a porsche boxer engine stuffed into a slick mooney airframe mooney even stretched the cabin to sweeten the deal cue the list six cylinders overhead cams electronic ignition tuned induction fan cooling automatic mixture and prop controls for pete's sake who wouldn't want a freaking porsche engine in their airplane evidently hardly anyone did except for 41 adventurous souls who bought the airplane before porsche bailed on it a couple of years after it was introduced this should have been a slam dunk but it wasn't as with the tealer diesel the engine had teething pains problems with valve springs mainly after good support initially porsche promised to fix it but never did i don't know this seems like a german thing anyway the owners got pissed and sued and porsha eventually paid to have the engines replaced with wait for it the continental i o 550. some of the pfm moonies were shredded by hurricane charlie which struck puna gorda florida in 2004 the moonies were there for the conversion when mooney was bought by chinese interest in 2013 the company came with all the factory tooling and manufacturing rights and also a case of amnesia a year after the purchase mooney announced the three-seat m10 trainer powered by you guessed it the same t-or diesel engine diamond swarat except it wasn't exactly the same the engine had been sorted out by then and was and is still made by continental who snapped up tealer out of bankruptcy in 2013. within three years mooney can the m10 project but actually it might have been a nice little airplane with the improved engine but they realized there was just no substantial market for a trainer costing north of 300 000 bucks the engine may have been irrelevant not to be denied its me too moment in diesel world cessna announced in 2007 that it would offer a diesel version of the venerable skyhawk the airplane was already approved for the tailored engine under an stc but then cessna caught wind of tealer's troubles and say what you might about cessna it has seen enough of the aeronautical river to recognize a turd floating past when it sees one that project was quietly cancelled undeterred cessna tried again with this engine in the 182. that was in 2012. it's the sr-305 diesel from sma they bailed on that project soon afterwards sears tried this engine too and couldn't make it work it had significant cold starting and cold weather problems by the way that stc that supplemental type certificate in case you're unfamiliar for the improved tailored continental engine allowed several companies to offer diesel conversions for the skyhawk these have found some traction but the volume is really small one that vividly illustrates how the market doesn't always embrace new technology is this one this is the redbird red hawk you'll know redbird as the simulator company but in 2013 it started an ambitious project to refurbish older skyhawks with the improved tailored engine and new avionics here's how the numbers worked out on that which is to say pretty favorably great flying airplane too at the time the redhawk was introduced its operating costs were only slightly less than the gasoline version but these improved as the engine got a higher tbr that's time between replacement redbirds sold about 15 of these airplanes but here's where it gets interesting redbirds submitted a bid to replace the fleet of a major flight university and they won on the low bid but they didn't get the order and why not probably because the big schools aren't as interested in low operating costs as they are in predictability reliability and dispatch ability and they didn't want to invest in new support infrastructure for the diesel they know what a new skyhawk and an archer will do and there is still a long memory about diamond's tailor troubles also redbird had continuing problems getting the engines and parts delivered from germany on time at the time there was no u.s service center for the engines piper now offers the continental version of the diesel in the archer dx and it has found some buyers but not a lot okay summing up here mercedes-benz porsche taylored continental is there anyone i've forgotten oh yeah toyota and honda in the mid-1990s toyota engaged a bunch of smart engineers at hamilton standard to certify this a lexus v8 for aircraft use it became the fv4002tc and they didn't just certify it they got a production type certificate they could have started building and shipping it cirrus would have bought it for sure except cirrus wasn't a thing back then this would have been a kick-ass airplane motor 360 horsepower fedex-controlled and water-cooled weighed about 520 pounds and had a best bsfc around 0.39 it's almost a high-tech i o 550. why didn't they like take over aviation with this terrific engine i can never get an answer on why they didn't go forward but i suspect someone in the toyota c-suite said are you people nuts all this liability to sell 300 engines a year back then lexus was building about a hundred thousand cars a year honda was pumping out the cars then two and a few years later it revealed as how it was working on something called the hap engine in a partnership with continental it was a four-cylinder water-cooled design with 225 horsepower that's a really nice number for a light four banger but honda apparently lost interest the engine by the way used the same fedex that hamilton standard developed for the toyota lexus engine if all this gives you the impression that new engines for airplanes are a gaping black hole well maybe you have to be slightly delusional to propose one and there are successes like these three the rotax 912is the lycoming i o 390 and the new but little celebrated lycoming ie2 the is is almost a standard in the light sport industry now and it's just an improved version of the 912 with fuel injection and electronic ignition the io390 was developed from the i o 360 as an experimental engine and is finding market traction as a replacement and finally found a spot in the cirrus sr20 that only took about 18 years the ie2 is based on the i o 540 and it's the intriguing one here it's a fully electronic engine used in the technam p212 traveler i reported on recently from sun and fun i'll do a detailed video on it later one thing all these successful engines have in common is that they aren't clean sheet designs but incremental improvements on successful engines the i o 550 is another example of that and not an overhead cam in the bunch historically new engines haven't always failed because the tech didn't work or because automotive engines can't hack the airplane duty cycle they failed for lack of will with will sometimes being defined as money think of venn diagrams which i like to call circles of audacity one of the circles isn't that buyers want the thing because buyers don't know what they want until they see it allen klappmeyer cirrus likes to remind people that cirrus market surveys revealed nobody wanted glass panels but everybody bought them when they became available to succeed the funding and let's just call that commitment has to be there it wasn't for rotax toyota or honda another recent failure worth of mention is the eps eight cylinder diesel great on paper ran out of money to succeed the engine has to actually do something better than what it replaces it has to work the porsche engine didn't and was a little worse the sma diesel is another example of just not working finally the whole enterprise rides on support and warranty without that you get a tailored or a porsche and a lasting bad taste in the market in retrospect the austro-engine never should have succeeded it's expensive heavy and complex to manufacture many people including me thought it couldn't succeed i mean seriously a cast iron block and an airplane engine today diamond owns the light twin market they sell more twins than piper technem and textron combined almost all diesel the reason the astro did succeed if at low volume is sheer force of stubborn will by christian juries who force the circles to gather against the laws of nature and if you want to build a new airplane engine and succeed that's evidently what it takes for avweb i'm paul thanks for watching

Channel: AVweb

Views: 718,777

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Id: _k1TQGK3mZI

Length: 22min 48sec (1368 seconds)

Published: Sun May 16 2021