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  #1  
Old 01-20-2005, 08:09 AM
f1rocket's Avatar
f1rocket f1rocket is offline
 
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Location: Martinsville, IN
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Default Are you ready to be a test pilot?

Okay, this is the debate section, right? So let's entertain a discussion regarding alternative engine options.

I did a little research. I looked at all the RV accident reports for 2004 and pulled all the "engine problem" ones. I found 7 accidents. 5 of the seven involved Lycoming engines, 1 involved a Subaru, and 1 involved a Chevy V8.

Within those categories, I looked at final reports to see the root cause of the engine problem. On the Lycoming, 1 is a preliminary report so I don't know. 3 were caused by fuel exhaustion, 1 by a oil cooler line failure. None were caused by any internal engine problem. The Subaru went down due to vapor lock at cruise. The Chevy went down because of internal engine failure of the main bearings.

What can one derive from this? Not much really, but you can extrapolate some indications. When you consider the tens of thousands of hours put on Lycomings each year, it sure looks like the Lycomings are pretty reliable as long as you feed it fuel and oil. When you consider the very small number of hours put on alternative engines in a year, the picture is less rosy.

I guess that's my point. If you chose to drop an alternative engine in your RV, be sure you're willing to accept the proposition that you are a powerplant test pilot. Just because there's a few Subarus, Mazdas, and Chevys flying successfully, doesn't necessarily mean that your usage will be trouble free. There aren't enough hours put on these engine to derive any meaningful statistical conclusion as to their reliability. I'm not saying that they aren't reliable, and I'm not saying that they are. The point is there's no numbers to prove it one way or the other. If you can live with that, then go ahead and experiment.

One of the reasons folks choose the Subaru package, in particular, is cost. I suspect, but would like to see some hard numbers, that when its all said and done, you will likely have nearly as much money in a Subaru package as you will in a Lycoming. And don't quote me prices on the NEW Lycoming, because you're not getting a NEW Subaru either. You're getting one out of a salvaged automobile. When you consider resale value of your RV, I bet that Subaru will cost you much more money in the long run.

I'm a chicken, I admit it. When it comes to swinging the prop around, I don't mess around much. People have been trying to convert auto engines for aviation use since the 1960s. Personally, I don't think there's any magic out there to be uncovered. I have confidence in my building skills so I'm not afraid of pulling the wings off or losing my tail feathers. But when the prop stops turning, I have a big problem and a heavy glider on my hands.

I think there's more promise with newer designs like the diesel and turbine engine prototypes. In the meantime, I think I'll stick with what has a proven track record of reliability. I admire all you test pilots, and I hope your projects are very successful and safe.
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Greenwood, IN

www.pflanzer-aviation.com
Paid through 2043!
Lund fishing Boat, 2017, GONE FISHING
RV-12 - Completed 2014, Sold
427 Shelby Cobra - Completed 2012, Sold
F1 EVO - partially completed, Sold
F1 Rocket - Completed 2005, Sold
RV-7A - Partially completed, Sold
RV-6 - Completed 2000, Sold
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  #2  
Old 01-20-2005, 04:03 PM
fredmoss fredmoss is offline
 
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Posts: 25
Default You're a Test Pilot Every Day

Everytime you go up in a plane -- even a passenger airliner -- you're putting your life in someone else's hands.

You're placing your life in the hands of of, occasionally, disgruntled aircraft mechanics or over-worked ATC's and the only protection you have is tonnes and tonnes of government regulations, drafted by other disgruntled government employees, many of whom aren't pilots, that you hope they follow.

The aircraft industry is stagnant. Concorde is dead, the "new designs" coming out of Boeing and Airbus are just larger re-hashes of 30-40 year old designs.

GA is even worse -- there hasn't been a significant innovation in GA design for 35 years. Cirrus is a nice, old design, with new materials, but at $400,000 a pop, not many of us will be flying them soon.

In comes the Kit Plane industry -- Innovation, intelligence, ingenuity and affordability. And, all it asks in return is that we take personal resonsibility for our choices. No lawyers, just men, women and their minds -- and, in some cases, their bodies. The Kit Plane industry will save GA from itself -- if we can keep it free.

We are ALL going to have to make tough decisions about our powerplants in the not to distant future when 100LL is no longer availiable -- that is not an "if", it's a "when". Lycoming and Continental aren't telling us what plans they have, if any.

There are a few alternatives on the horizon down the certified path, Wilksh, SMA, Centurion -- all expensive and all unproven by large statistical samples.

Automobile engines are, for many reasons, superior in all ways (performance, reliablity, economy) to the 40 year old designs coming out of Lycoming and Continental. Automobile conversions have not, traditionally, been very successful. Mostly because conversion were undertaken not to provide superior performance, but to provide a "cheap" alternative to certified engines.

There are engineers out there now, who are creating high-quality, high performance, but not necessarily lower-cost conversions that, in at least one case, have been achieving their goals.

Everyman has to make his own decision on what risk he's willing to take. You do the research, you talk to the engineers (When was the last time you got the lead engineer from Lycoming on the phone?), talk to those flying the engines, get the data -- then use your own brain and make a decision.

There is a movie, based on a famous book, called "The Fountainhead". A brilliant architect, named Howard Roarke, designed buildings based on new materials and new technologies. He refused to make them look more safe and familiar by incorporating useless classical additions. Everyone said his building would fall, that they were unsafe, but they stood and were magnificent.

No one will deride you for taking the safe, certified path -- and many will deride you if you take the Howard Roarke path. But ultitmately, it's a personal decision. You have to ask yourself, why are you flying a kit plane instead of a certified Cessna 150?
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  #3  
Old 01-20-2005, 08:54 PM
bhassel's Avatar
bhassel bhassel is offline
 
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Default eSubie's

Actually the newer model eSubie's (Eggenfellner) are new engines, not used engines.

There are advantages and disadvantages in going with either the eSubie's or the Lycosaurus. The eSubies can provide real heat to the cockpit. There is reduced complexity in the cockpit with no mixture controls to worry with or prop controls either. Then there is the easy installation; hooked up and runnng in a day or less (plug and play). You also have the option of boosting with a supercharger to maintain power at higher altitudes.

$ for $ even if the eSubie's may be comparable in price they do offer some advantages that the Lycosaurus does not.

In the end I may very well use a cheap used Lyco. But it'll be just because of the lower up front costs. That doesn't mean I believe it's actually the best solution.

Now if I could afford a new lyco then I'd be hard pressed not to get an eSubie instead!
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  #4  
Old 01-21-2005, 08:08 AM
f1rocket's Avatar
f1rocket f1rocket is offline
 
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Location: Martinsville, IN
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Default

Oh boy, where do I start.

Automobile engines may be of a higher technical level than a Lycoming, but they are NOT superior when it comes to driving an airplane through the sky. Take a look at the main crank bearings and the engine block of a Subaru and compare them to the Lyc. When you are swinging the weight of the prop out front, it requires some hefty support. Lyc's also deliver peak power at low RPM, while the Subies need to scream along at much high RPM to deliver peak horsepower, hence the gear reduction units. I contend that automobile engines are very poor airplane engines because they need to be jerryrigged to make them work.

The benefit they have is that they are cheap because they are mass produced. Can't beat that. They also have great reliability when used for their intended and designed use. Start sticking them in airplanes and you are bringing along a whole additional set of engineering problems to be solved. I don't know any engine engineer that thinks gear reduction units are the best way to turn a prop. No, it's just a band-aide stuck on an engineering problem that otherwise, can't be fixed.

The whole 100LL thing has become the enabling battle cry of the alternate engine groupies. Unfortunately, it doesn't hold water. No one is going to wake up one moring to find that hundreds of thousands of engines that use the product suddenly are silent because no one is making it any longer. I don't doubt that there will be a transition to other fuels in the long run. That's probably why the diesel engine is looking like a viable engine alternative. But you and I will be able to buy 100LL for many, many years to come. Now the price of that gallon of 100LL may be another issue.

Finally, the reason I fly a homebuilt and not a Cessna 150 is because I can upgrade my Lycosaur with electronic ignition, FADEC, etc and get the best of both worlds----newer features and capabilities with proven reliability.
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Randy Pflanzer
Greenwood, IN

www.pflanzer-aviation.com
Paid through 2043!
Lund fishing Boat, 2017, GONE FISHING
RV-12 - Completed 2014, Sold
427 Shelby Cobra - Completed 2012, Sold
F1 EVO - partially completed, Sold
F1 Rocket - Completed 2005, Sold
RV-7A - Partially completed, Sold
RV-6 - Completed 2000, Sold
Long-EZ - Completed 1987, Sold

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  #5  
Old 01-21-2005, 08:27 PM
Tom Maxwell Tom Maxwell is offline
 
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Location: Houston, TX
Posts: 213
Default Where are the rebuttals??

This is a good thread and I am surprised that others haven't chimed in by now. I am not an engineer so I cannot provide objective data, frankly I haven't seen a comparison, but here are my thoughts, whatever they are worth.

Automobile engines may be of a higher technical level than a Lycoming, but they are NOT superior when it comes to driving an airplane through the sky.

Maybe not superior but I don't feel they need to be considered inferior either. They are the product of years and years and years of engineering by some of the best engineers in the world and by companies with very deep pockets. They are outstanding machines and I see no data to suggest they are inferior when it comes to moving an airplane.

Take a look at the main crank bearings and the engine block of a Subaru and compare them to the Lyc. When you are swinging the weight of the prop out front, it requires some hefty support.

Agreed, it does take support. But just looking at the physical size of the bearings is not all that needs to be considered. The Subaru has more bearings and they are spaced much more closely together. This provides for a great deal of support and also makes for a smooth running engine capable of very high RPMs. In addition, PSRUs actually help provide support and also isolate the engine crank from a lot of abuse. Finally, combine these super smooth running engines with a well balanced lightweight prop and a lot of the abuse is eliminated. I agree that with all else being equal (which it isn't) a Lyc would seem to be the sturdier of the two, but when the entire package is considered, the auto engines actually punish the components and the airframe less and therefore may even be superior.

Lyc's also deliver peak power at low RPM, while the Subies need to scream along at much high RPM to deliver peak horsepower, hence the gear reduction units. I contend that automobile engines are very poor airplane engines because they need to be jerryrigged to make them work.

Yes and no. Yes they do run at high RPMs, they are designed to run at high RPMs. This is not in itself a negative. Running an engine at 3500-5000 RPM that can run easily at 7-8K is not a big deal. I don't view a PSRU as a "jerryrig," we have been using geared units on cars for decades (we call them transmissions and differentials) and they seem to work pretty darn well. Sure it is another point of possible failure, but the history is pretty good on them so far. Granted they don't have the history of the Lyc but they seem to be pretty good non the less.


The benefit they have is that they are cheap because they are mass produced. Can't beat that. They also have great reliability when used for their intended and designed use. Start sticking them in airplanes and you are bringing along a whole additional set of engineering problems to be solved. I don't know any engine engineer that thinks gear reduction units are the best way to turn a prop. No, it's just a band-aide stuck on an engineering problem that otherwise, can't be fixed.

Yes the auto engines certainly are more economical and they are very reliable. Although the initial cost is about the same, this is more a result of the number of suppliers and engineering start up costs. These costs will come down as more are produced and FWF packages are finalized. But even at current costs the fuel cost savings of a conversion over the life of the plane will be very significant. Yes resell costs may be lower, but then again, maybe not 10 years from now. But who cares? If you plan to sell your plane in a year or two it may make a difference, but if you plan to fly it for 8-10-12 years or more, you make up that difference in fuel costs alone. Run the engine out and if the buyer wants a Lyc 10 years from now, let him strap one on and go. I don't agree with the "bandaide" reference. It implies a temporary fix to something that is broken. Sure the conversions are a different solution, but I don't see any evidence to support that they are a broken or substandard solution. I guess I will take your word on the engineer comments, I have not seen any polls on the issue. I am curious about how many engineers you have queried and why they feel a PSRU is not a viable solution.

The whole 100LL thing has become the enabling battle cry of the alternate engine groupies. Unfortunately, it doesn't hold water. No one is going to wake up one moring to find that hundreds of thousands of engines that use the product suddenly are silent because no one is making it any longer. I don't doubt that there will be a transition to other fuels in the long run. That's probably why the diesel engine is looking like a viable engine alternative. But you and I will be able to buy 100LL for many, many years to come. Now the price of that gallon of 100LL may be another issue.
Finally, the reason I fly a homebuilt and not a Cessna 150 is because I can upgrade my Lycosaur with electronic ignition, FADEC, etc and get the best of both worlds----newer features and capabilities with proven reliability.[/quote]

Maybe yes maybe no. While there doesn't appear to be any indications of a shortage of 100LL anytime soon, we just don't know what the future will bring. You state that we will be able to buy 100LL for many, many years to come. I am not sure how you have reached this conclusion, I don't see any evidence to know one way or the other. I think we all agree that there is some pressure on 100LL. What that pressure will bring or how long it will take is not known but I suspect that it will not result in better availability or lower prices in the future. As far as EE, Fadec, etc. these are certainly not advantages over an auto conversion. The auto engines were designed with these features in mind from the ground up. I guarantee that GM and Subaru have put tons of more money into engine control research than all of the FADEC suppliers put together. I think it could be argued that adding FADEC to a Lycomming is a bandaide approach to engineering compared to the auto engines that were designed from the ground up with them in mind.

The biggest advantage I see to a Lyc is simply availability. They are available everywhere. Parts are readily available amd you can get them worked on at almost any airport. You can buy auto engine parts off the shelf but finding FWF parts for them at remote airports and finding someone to put them in for you might be a challenge. This will change as more and more become in use. Hey at one time I bet finding Lyc parts and someone to work on them was tough also.

The biggest advantages I see to conversions is that they represent the latest and very best in engineering, they are water cooled and they run super super smoothly. I hear people talk about a smooth running Lyc but compare it to the audio on Jans web site of the Subaru and then tell me in good conscience that a Lyc runs smoothly.

I compare the Lyc to a Subaru as a Harley to a Gold Wing. They will both get your down the road. The Harley has a cool factor to it and its long heavy stroke creates a not so smooth ride. The Gold Wing, on the other hand, may not be as cool or may not have been around as long, but it will get you where you want to go using the latest in engineering technology and it purrs like a kitten.

Bottom line is they will both get you to your destination and pretty darn well. Some like the features of the new engines and the excitement of trying new technology, some are more comfortable with the proven Lyc. To each his own.
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  #6  
Old 01-21-2005, 09:19 PM
N916K's Avatar
N916K N916K is offline
 
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Default dropping the kids off in your RV?????

I was really interested in the subject a few years back. I wanted to believe that a modern car engine was better. It didn't really take long to come to a conclusion once I really thought about it.

First of all I work as a vehicle dynamics engineer in the auto industry. I'm out every day pounding cars on the test track. One thing is very clear when you are driving a car at 100% all day (most people only drive at a small percentage of that, eventhough they may believe they drive around fast). Not all engines and transmissions are the same. They are built with specific jobs to do. For example, the Toyota V6 gas engine is a great car engine. When they stick it in the 4Runner it's a real piece of junk, the torque is way up high, you can't pull up a hill at all unless you slip the clutch. It was not made for that application so it fails at being a truck motor. Take a look at the Ford 6.0 Deisel, they are a great truck engine. Really stink for soccor moms driving kids around town. Drivability is very poor compared to a quick responding gas motor.

The point is, airplane engines are basically generators. They cruise along at a constant speed, don't require any transients. Except for a couple of deisel truck engines, the typical car engine just isn't made for that. Even a Vette motor can't take high speeds for more than a minute or so. (Before I get a bunch of bowtie poeple yelling at me, I've broken more vettes on a track that you can imagine) And all those Honda, Nissan, Toyota, Subaru guys, yes they have all been towed off the track with broken motors from sustained high engine speeds.

So in conclusion I chose to go with an airplane engine. You enjoy whatever engine you pick and I wish everyone a great time flying their plane. Just please stop argueing that a car engine is made for sustained high engine speeds and power, it just isn't. They are made to make soccor moms and Uncle Sam happy not to power generators.
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  #7  
Old 01-21-2005, 09:23 PM
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Kevin Horton Kevin Horton is offline
 
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Location: Green Bay, WI, USA
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Default Engineering?

Quote:
Originally Posted by Tom Maxwell
Maybe not superior but I don't feel they need to be considered inferior either. They are the product of years and years and years of engineering by some of the best engineers in the world and by companies with very deep pockets. They are outstanding machines and I see no data to suggest they are inferior when it comes to moving an airplane.
Quote:
Originally Posted by Tom Maxwell
The biggest advantages I see to conversions is that they represent the latest and very best in engineering, they are water cooled and they run super super smoothly. I hear people talk about a smooth running Lyc but compare it to the audio on Jans web site of the Subaru and then tell me in good conscience that a Lyc runs smoothly.
We need to make a very clear distinction between the engine core, supplied by the automobile manufacturer, and all the essential accessories and mods that are required to create an aviation powerplant.

The automotive engine core is likely very well engineered, and may be extremely reliable, even when used in a different mission than it was designed for. But, every automotive conversion I have seen had a number of essential items that were either designed by the builder or the conversion manufacturer (e.g. reduction drive, cooling system, fuel delivery system, etc.). These essential accessories are not nearly as well engineered as the engine core, yet a failure of one of them has the same effect as a failure of the engine core. For example, a local RV-7A builder had an engine failure (one of the more popular automotive conversions that is touted as running very smoothly) that was due to vapour lock due to a design problem in the firewall forward kit. The conversion manufacturer acknowledged a design problem, and later provided a modified part. The builder sold the aircraft, and is building a new one, which will have a Lycoming. I am aware of an Mazda rotary powered RV that had an engine failure due to a problem with the builder installed carburetor. Another RV had an engine failure when the supercharger belt came off in flight.

So, don't think that the "superior" engineering of the engine core necessarily translates into higher reliability than you would get with a Lycoming. If you want to install an automotive conversion, it's your aircraft, do what you want. But please don't kid yourself that you are doing it to get higher reliability.
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  #8  
Old 01-21-2005, 10:23 PM
Tom Maxwell Tom Maxwell is offline
 
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Location: Houston, TX
Posts: 213
Default Yes Indeed

I agree, the whole package needs to be considered. These conversions are pretty new and with any new endeavor there are going to be start-up issues and engineering issues to resolve. Although I am much to young to know , I think there must have been issues with the first Lycomming engines as well. There are probably some on these boards who can tell a few stories about early Lycomming engines.

Things do happen with machines, no question. The examples you cite seem to me to be problems that could have happened with Lycommings as well. I've heard stories about vapor lock and carb problems on Lycommings and I guess it isn't to far fetched to believe that a belt could break on a Lycomming supercharger. One of the first RVs I saw "live" was under repair following a forced landing. In talking to the owner, he said that a bearing had frozen and the piston rod twisted off. I guess what I am saying is that yes stuff does happen and it isn't limited to new packages. Frequently, the failures are not with the core engines at all but with the supporting equipment. I would expect to see more issues with these new package than with Lycomming packages and I expect the new packages to improve over time. Only time will really tell if these packages are realiable and if they are good alternative. I am sure there are thousands of Lycs flying and they have been for 30 years. In perpective I think Jan has 300+ Subies flying with only a few years of experience. We will see where it all leads.

I will definitely concede that a Lycomming is a proven workhorse and a safe choice. Much like choosing IBM in the 70's and 80's. I once had an executive tell me, "IBM may not be the best solution, but I won't get fired for choosing IBM." Today choosing an IBM alternative is not considered risky at all. I understand that everyone has different comfort levels, so to each his own. I fault nobody for not jumping on the wagon or for waiting until the new packages get more time and become more proven. Some will elect to be a part of the journey and others will sit back and watch, and that is OK.

What do you think about the Lyc alternatives. Are they better or just-as-good or do they have issues that make pure Lycommings better?

As I said, I am not an engineer so I do appreciate the engineering perspective and your thoughts. Thanks for you input. I would be interested in hearing what the failures were in the auto engines after running them for long periods of time at high speed and how the engines might be improved to handle it. Or is the only answer to piston powered flight a long, hard, slow stroke and lots of beef to handle it?

Thanks again for the discussion.
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  #9  
Old 01-22-2005, 06:41 AM
Highflight Highflight is offline
 
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Location: Houston, TX
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Default

Quote:
Originally Posted by Tom Maxwell
What do you think about the Lyc alternatives. Are they better or just-as-good or do they have issues that make pure Lycommings better?
A couple of weeks ago, the differences between how Lycomings are built and the things that are different when building the same base design but by different companies (Superior and Mattituck) were posted on the Lycoming Yahoo group.
There's a good handful of improvements that the two other builders have done to their engines and they all make lot's of sense.

Are they better than the Lycoming brand?... I don't know, but the improvements do seem to be geared toward dependability and durability issues so the answer is; maybe and/or probably if the improvements really DO add dependability or durability to the basic design .

And something else that should be said about the "60 year old design" still built by Lycoming and now the same design used by other companies is that there have been major advancements in the areas of metallurgy and other areas of engine design that weren't around 60 years ago.
Those advancements give us things like Nikosil lined cylinders, flow control for smoother running, and better implementation of internal oil dispersion and stuff like that. Those things, as basic as they are today, were not likely incorporated to any great degree in the original Lycoming design.

So perhaps the Subie and Mazda fans might consider that the basic mechanical design of the "old" Lycoming type engine, coupled with modern materials and engineering of things not even thought of 60 years ago, make the Lycoming a better and more reliable choice than the car engine people like to think.

Vern
RV7-A

Last edited by Highflight : 01-22-2005 at 06:44 AM.
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  #10  
Old 01-24-2005, 10:43 PM
Darrell514 Darrell514 is offline
 
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Location: Sheridan, WY 82801
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Default

I don't know the reason other people want an alternate engine over Lycomings but the reason i do is smoothness. It doesn't mater how much modern materiel you put in it is still going to be a big bore strong pulse thumper.You can't make a Gold wing out of a Harley. I presently fly a Kitfox with the Rotex 912 and have had a lote of comments on how smooth it is compared to Lycs. I don't know if i will go with a auto converson,probably the Deltahawk if it works out but not a Lycoming unless they are giving them away.Once you've flown smooth you will never go back.The airplane might like you better to

Darrell RV9A
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