VLJs again
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I do know this stuff. You needn't get so worked up, but at least agree that a high bypass ratio "jet" engine is pretty close to the idea of a turboprop. Or don't agree, either way enjoy your lunch.
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It's still not much of a proper airplane if you have to take a dump in bag due to lack of a toilet. You can compare fuel consumption, operating costs, whatever...but it all comes down to the toilet. True.
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Many years ago, when I was flying a Shrike Commander for my boss at Flying Magazine--you kids probably don't know what a Shrike is, but never mind--that had a fancy club-seating interior with all the 1970s comfort-in-flight accoutrements, I had my then-girlfriend pee into the empty ice container between the two plush back seats because I didn't want to give up altitude and a tailwind to land.
It always amused me when I'd thereafter hear Ed Muhlfeld, in back, say, "Another Scotch on the rocks, Bob?..."
It always amused me when I'd thereafter hear Ed Muhlfeld, in back, say, "Another Scotch on the rocks, Bob?..."
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Sorry to disappoint - been flying for 18 years so far so I'm not going to Ryanair anytime soon - wouldn't touch them with a stick
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Suitecaseman:
- The reverse flow of the PT6 isn't changing anything about the basic concept. Replace a PT6's propeller by a fan and you get a turbofan, even with a reverse flow. The reason behind the PT6 reverse flow is mainly to put the accessory gearbox at the back of the engine since it isn't meant to be attached on pylons. The core engine is the same, it produces thermodynamic energy absorbed by a turbine and transferred to a fan or propeller through a shaft.
- According to a lot of people the fan and the low pressure compressor are two different things, you're not gonna compress much of air with a turbofan's fan... Just search turbofan cutaway in google image and you will get my point. The low pressure compressor is a multi-stage compressor.
- Adding a gearbox to a turbofan is an improvement on which P&W is working (PW1000). Since you like to quote P&W this comes from their website and contradict your point about low pressure compressor:
In the PurePower PW1000G engine, a state-of-the-art gear system allows the engine’s fan to operate at a slower, optimum speed while freeing the low-pressure compressor and turbine to operate at their optimized higher speed, increasing engine efficienc
- Anything else on your list?
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At least I'm focusing on factual/documented points while you are only basing your disagreement on comments toward my "attitude". I think this isn't bringing any further during an interview... but technically it looks like I'm little bit right... sorry.
What do you call the conventional sense? Why a PT6 with a fan wouldn't be a turbofan? Wouldn't it be a turbine and a fan?!?
What do you call the conventional sense? Why a PT6 with a fan wouldn't be a turbofan? Wouldn't it be a turbine and a fan?!?
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Nope - that would be a turbine with a thingy up front apparently. 
Whatever.
Sorry I even started you guys on the fan discussion - it was meant as an amusing thought. Who cares if you got frikkin ramjets stuck on the plane - it all boils down to whether or not you can get pax in it.
Fact still remains, the general public considers anything with a prop to be a smaller and lesser airplane. They haven't seen the TU195 obviously. It is a little disheartening to hear fellow pilots reason the same way.
On a side track it'd be interesting to see what effect a turbofan would have on the performance of the Avanti. Sleek as it is, I'm guessing it'd burn more fuel for the same basic performance.
Whatever.
Sorry I even started you guys on the fan discussion - it was meant as an amusing thought. Who cares if you got frikkin ramjets stuck on the plane - it all boils down to whether or not you can get pax in it.
Fact still remains, the general public considers anything with a prop to be a smaller and lesser airplane. They haven't seen the TU195 obviously. It is a little disheartening to hear fellow pilots reason the same way.
On a side track it'd be interesting to see what effect a turbofan would have on the performance of the Avanti. Sleek as it is, I'm guessing it'd burn more fuel for the same basic performance.
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On a side track it'd be interesting to see what effect a turbofan would have on the performance of the Avanti. Sleek as it is, I'm guessing it'd burn more fuel for the same basic performance.
Turbofans exists with various bypass ratios allowing to choose between different performance profiles. A high bypass ratio turbofan will be more fuel efficient in low speed/altitudes than a smaller bypass ratios based on a similar core engine which in the other hand would perform better in high speed/altitudes.
A very good example is the A10 which uses high bypass ratio turbofans in order to perform well with heavy load and low speeds/altitudes. With a similar bypass ratio than the Phenom's engines it would need 3 times more runway to take-off at MTOW and double it's fuel flow. At the same time very fast turboprop's propellers tends to look very much like fans..
When you have a big difference of velocity between the air flowing out of the engine's fan, propeller or nozzle and the surrounding airflow you waste a lot of energy and reduce performances. This is why at low speeds it's more efficient to give a small acceleration to a large volume of air while at high speeds you need to do the contrary.
Last edited by S.F.L.Y; 10th Jan 2010 at 22:21.
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You obviously never flew a PT6 with curved exhaust pipes nor understand what the reverse flow is about.
I'm not saying anything of what you pretend, turboprops have been designed for specific purposes like short distances operations on which jets wouldn't have enough cruising time to balance their higher fuel consumption for takeoff and climb. Jets are definitely better on long ranges.
Flying a jet (with a low bypass ratio) on short ranges doesn't make a lot of sense from an economical point of view. If on top of that you operate it above it's flat rating temperature, in a salty, dusty and polluted environment, maintenance costs will increase exponentially due to thermal stress and accelerated corrosion.
I'm not saying anything of what you pretend, turboprops have been designed for specific purposes like short distances operations on which jets wouldn't have enough cruising time to balance their higher fuel consumption for takeoff and climb. Jets are definitely better on long ranges.
Flying a jet (with a low bypass ratio) on short ranges doesn't make a lot of sense from an economical point of view. If on top of that you operate it above it's flat rating temperature, in a salty, dusty and polluted environment, maintenance costs will increase exponentially due to thermal stress and accelerated corrosion.
Sorry to drag this discussion further off topic - but does anyone remember the King Air/Meteor hybrid pic from a while back (like 10 years or so)? I think it was on the cover of Controller or similar... If anyone has a copy, I'd love to see it again!
btw - I always assumed it was a montage, but I'm happy to be educated
Rgds.
btw - I always assumed it was a montage, but I'm happy to be educated
Rgds.
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"Do you really fly with no clue of theory? Let's not call it only theory but also experience if this is fine for you..."
I indeed am curious, not trying to be a pain, but do answer the question. If you asked it of me, I certainly would have no trouble doing so.
I indeed am curious, not trying to be a pain, but do answer the question. If you asked it of me, I certainly would have no trouble doing so.
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I indeed am curious, not trying to be a pain, but do answer the question. If you asked it of me, I certainly would have no trouble doing so.
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Suitcaseman, if the thread was titled "2 underacheivers having a willey waggling contest" obviously I would have passed it by, unfotunately it's called "VLJ's again" which could have been more interesting.
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Phil, in our industry communication skills and politeness are essential. If you want to know my name you ask it politely.
I'm basically developing on this thread (VLJs) by providing information which I can document. I'm entering into technical issues as this is critical when it comes to flight operations and if you had a little understanding of what I'm talking about you would understand how relevant it is to the thread. You can either debate providing factual info or just stop reading what doesn't deserve your valuable attention.
I've been working on evaluating VLJ operations performances and thought I could share my point of view.
I'm basically developing on this thread (VLJs) by providing information which I can document. I'm entering into technical issues as this is critical when it comes to flight operations and if you had a little understanding of what I'm talking about you would understand how relevant it is to the thread. You can either debate providing factual info or just stop reading what doesn't deserve your valuable attention.
I've been working on evaluating VLJ operations performances and thought I could share my point of view.