Power Recovery Turbine (PRT)

[skilzz]

saw it in class today.
compared to variants not equiped with this system gains were anywhere from 800hp-1200hp :O



A Turbo-compound engine is a reciprocating engine that employs a blowdown turbine to recover energy from the exhaust gases. The turbine is usually mechanically connected to the crankshaft but electric and hydraulic systems have been investigated as well. The turbine increases the output of the engine without increasing its fuel consumption, thus reducing the specific fuel consumption. The turbine is referred to as a blowdown turbine (or power-recovery turbine), as it recovers the energy developed in the exhaust manifold during blowdown, that is the first period of the exhaust process when the piston still is on its expansion stroke (this is possible since the exhaust valves open before bottom dead center).



THE R-3350 :O(yea im still amazed)

The Wright R-3350 Duplex-Cyclone was one of the most powerful radial aircraft engines produced in the United States. It was a twin row, supercharged, air-cooled, radial engine with 18 cylinders. Power ranged from 2,200 to over 3,700 hp (1,640 to 2,760 kW), depending on the model. First developed prior to World War II, the R-3350's design required a long time to mature before finally being used to power the B-29 Superfortress. After the war, the engine had matured sufficiently to become a major civilian airliner design, notably in its Turbo-Compound forms.

Following the war, in order to better serve the civilian market, the Turbo-Compound[2] system was developed in order to deliver better fuel efficiency ("gas mileage"). In these versions of the engine, three power recovery turbines (PRT) were inserted into the exhaust piping of each group of six cylinders and geared to the engine crankshaft by fluid couplings in order to deliver more power (rather than by using the exhaust to deliver additional boost as in a turbocharger). The PRTs recovered about 20 percent of the exhaust energy (around 500 HP) that would have otherwise been wasted, but unfortunately had a negative effect on engine reliability, causing many aircraft mechanics of the day to nickname them "Parts Recovery Turbines" (and worse).
By this point reliability had improved with the mean time between overhauls at 3,500 hours and specific fuel consumption in the order of 0.4 lb/hp/hour (243 g/kWh). Engines still in use are now limited to 52 inches of Hg manifold pressure, being 2,880 HP with 100/130 octane fuel (or 100LL) instead of the 59.5 inches and 3,400 HP possible with 115/145, or better, octane fuels, which are no longer available.

[owequitit]

saw it in class today.
compared to variants not equiped with this system gains were anywhere from 800hp-1200hp :O



A Turbo-compound engine is a reciprocating engine that employs a blowdown turbine to recover energy from the exhaust gases. The turbine is usually mechanically connected to the crankshaft but electric and hydraulic systems have been investigated as well. The turbine increases the output of the engine without increasing its fuel consumption, thus reducing the specific fuel consumption. The turbine is referred to as a blowdown turbine (or power-recovery turbine), as it recovers the energy developed in the exhaust manifold during blowdown, that is the first period of the exhaust process when the piston still is on its expansion stroke (this is possible since the exhaust valves open before bottom dead center).



THE R-3350 :O(yea im still amazed)

The Wright R-3350 Duplex-Cyclone was one of the most powerful radial aircraft engines produced in the United States. It was a twin row, supercharged, air-cooled, radial engine with 18 cylinders. Power ranged from 2,200 to over 3,700 hp (1,640 to 2,760 kW), depending on the model. First developed prior to World War II, the R-3350's design required a long time to mature before finally being used to power the B-29 Superfortress. After the war, the engine had matured sufficiently to become a major civilian airliner design, notably in its Turbo-Compound forms.

Following the war, in order to better serve the civilian market, the Turbo-Compound[2] system was developed in order to deliver better fuel efficiency ("gas mileage"). In these versions of the engine, three power recovery turbines (PRT) were inserted into the exhaust piping of each group of six cylinders and geared to the engine crankshaft by fluid couplings in order to deliver more power (rather than by using the exhaust to deliver additional boost as in a turbocharger). The PRTs recovered about 20 percent of the exhaust energy (around 500 HP) that would have otherwise been wasted, but unfortunately had a negative effect on engine reliability, causing many aircraft mechanics of the day to nickname them "Parts Recovery Turbines" (and worse).
By this point reliability had improved with the mean time between overhauls at 3,500 hours and specific fuel consumption in the order of 0.4 lb/hp/hour (243 g/kWh). Engines still in use are now limited to 52 inches of Hg manifold pressure, being 2,880 HP with 100/130 octane fuel (or 100LL) instead of the 59.5 inches and 3,400 HP possible with 115/145, or better, octane fuels, which are no longer available.

Cool concept, but not the best real world benefits.

[skilzz]

Cool concept, but not the best real world benefits.

i guess they had really crude stuff in WWII. like if turbo jet technology didnt come about they would of just keep building bigger and bigger radials

[npor]

yeah...I had one of those back on my plane back in the day..


got rid of it due to the MPG's

[owequitit]

i guess they had really crude stuff in WWII. like if turbo jet technology didnt come about they would of just keep building bigger and bigger radials

Yes, ultimately the radial killed itself. It was really well beyond its limits when the jet came to commonplace. Hell, the Boeing Stratocruiser had such routine engine failures, it was nicknaged the "best 3 engine airliner in the world." It wasn't uncommon back then to have multiple engine failures, which is why long range airplanes had 4 engines. If you were out over the middle of the Pacific, you wanted to know that hopefully at least 1 or 2 engines could get you home. That is also why early long range jets also had 3-4 engines. They proved several magnitudes more reliable right off the bat, but they were still prone to failure, so they put 4. That and the fact that they had relatively modest thrust capability to move such weight. Through the 70's and 80's the technology was refined so much that 2 engines is now enough. In all the years the Boeing 767 has been flying over the ponds, the number of engine shutdowns is so statistically insignificant it isn't worth mentioning. I think they have had less than 10 total in nearly 30 years and BILLIONS of flight hours. Oddly, it is almost to the point now where having more than two engines is almost a liability because all it does is double your chances that one will fail.

And seriously, with the last generation of Wright and Pratt and Whitney radials, you are talking 3,000-4,000 cubic inch engines with TONS of cylinders. It was just ridiculous. They even had walkways in some wings so that the engines could be checked on! The smoothness, power and altitude capability of the jet really revolutionized travel as we know it, and on average, it uses less gas than transporting the same number of people by car, not to mention the time savings.

The PRT is a great idea though, as it truely is free HP, well beyond what a turbo offers (still increases fuel consumption). If they could figure out how to refine it and make it not so mechanically complex, it could maybe go somewhere. With the advances in today's computer technology, metallurgy etc, it would be really cool to see this on a car. Route the exhaust to it, and mount it to the crank with some simple reduction gears etc. It would allow you to increase power substiantially as well as reducing or keeping MPG the same. I am sure the OEM's have worked with them, and probably can't find a feasible solution.

[npor]

Owequitit, how the hell do you know everything about everything? I swear to god, almost every thread you post in you post an in depth very educated post. How. Where do you gain your knowledge sir. Not highschool. What did/are you in college for. I demand to know how.

[loud92CB7]

Owequitit, how the hell do you know everything about everything? I swear to god, almost every thread you post in you post an in depth very educated post. How. Where do you gain your knowledge sir. Not highschool. What did/are you in college for. I demand to know how.

why do u think its just college that got him the knowledge? i honestly dont know where he got it but why does everyone make college out to be so big?

[The G-Man]

Owequitit, how the hell do you know everything about everything? I swear to god, almost every thread you post in you post an in depth very educated post. How. Where do you gain your knowledge sir. Not highschool. What did/are you in college for. I demand to know how.

He knows a lot about planes and cars. Is there anything else worth knowing about in life?

[Ghetto_CB7]

Yes

He knows a lot about planes and cars. Is there anything else worth knowing about in life?

Women.

[d112crzy]

So it's kinda like a short geared transmission for air planes?

[wed3k]

Owequitit, how the hell do you know everything about everything? I swear to god, almost every thread you post in you post an in depth very educated post. How. Where do you gain your knowledge sir. Not highschool. What did/are you in college for. I demand to know how.

it's called google.com

how do you think i worked as a computer technician without any training.

[Lil' Whitie]

lol so it does exist!

hahaha back when i started driving and wanted to 'turbo' my car i thought that what turbo's do. sorta like a supercharger and that. run a belt drive and the turbo sucks exhast fumes outta ur engine.

then if you want to be extreme add a supecharger on it! LOL

[joekt]

Yes, ultimately the radial killed itself. It was really well beyond its limits when the jet came to commonplace. Hell, the Boeing Stratocruiser had such routine engine failures, it was nicknaged the "best 3 engine airliner in the world." It wasn't uncommon back then to have multiple engine failures, which is why long range airplanes had 4 engines. If you were out over the middle of the Pacific, you wanted to know that hopefully at least 1 or 2 engines could get you home. That is also why early long range jets also had 3-4 engines. They proved several magnitudes more reliable right off the bat, but they were still prone to failure, so they put 4. That and the fact that they had relatively modest thrust capability to move such weight. Through the 70's and 80's the technology was refined so much that 2 engines is now enough. In all the years the Boeing 767 has been flying over the ponds, the number of engine shutdowns is so statistically insignificant it isn't worth mentioning. I think they have had less than 10 total in nearly 30 years and BILLIONS of flight hours. Oddly, it is almost to the point now where having more than two engines is almost a liability because all it does is double your chances that one will fail.

And seriously, with the last generation of Wright and Pratt and Whitney radials, you are talking 3,000-4,000 cubic inch engines with TONS of cylinders. It was just ridiculous. They even had walkways in some wings so that the engines could be checked on! The smoothness, power and altitude capability of the jet really revolutionized travel as we know it, and on average, it uses less gas than transporting the same number of people by car, not to mention the time savings.

The PRT is a great idea though, as it truely is free HP, well beyond what a turbo offers (still increases fuel consumption). If they could figure out how to refine it and make it not so mechanically complex, it could maybe go somewhere. With the advances in today's computer technology, metallurgy etc, it would be really cool to see this on a car. Route the exhaust to it, and mount it to the crank with some simple reduction gears etc. It would allow you to increase power substiantially as well as reducing or keeping MPG the same. I am sure the OEM's have worked with them, and probably can't find a feasible solution.

ooooooooooooh typo

[skilzz]

So it's kinda like a short geared transmission for air planes?

no. its like a turbo charger but it drives the crank anstead of a compressor

[owequitit]

Owequitit, how the hell do you know everything about everything? I swear to god, almost every thread you post in you post an in depth very educated post. How. Where do you gain your knowledge sir. Not highschool. What did/are you in college for. I demand to know how.

A lot of my knowledge comes from practical application. I have also learned that correlation of knowledge is extremely helpful, as well as prudent observation of other people, situations and things.

My formal training is in everything airplane related. Currently, I am working on my Master's in Safety Sciences, and haven't yet decided if I want to focus on Aviation Safety Management or Aircraft Accident Investigation. After that is done, I will either get my PhD in Aviation, or my MBA, perhaps both.

My informal training comes from my father, who is rather jaded and cynical of information. That is where I get my questioning and reasoning of all sources. I was somewhat naturally inquisitive as a child, always asking "why" and "how", and that sort of thought was always encouraged. Through life lessons and normal learning, I learned how to figure out how and why stuff worked, as well as what the slant or perspective was. I had one teacher in High School who was amazing. He retired as a full Colonel in the Air Force and had a vast amount of knowledge and compassion. He is the one I got my love of politics and economics from. I have had several other pivotal professors and role models along the way, each of whom I aspire to. As part of my somewhat "Type A" personality, I have also always had high standards and expectations for myself. Again, a lot of that is parenting.

I also have a near photgraphic memory, which helps. I really do remember almost everything. It is both a blessing and a curse.

I use those tools to seek new information and ideas, and then use that information and ideas to expand my thinking in other areas, as well as trying to use it to find new ones.