Turbo - prop/fan/jet ?

[ETOPS]

Can I log my Piper Navajo time as "Turbine" or "Turboprop" time, since the Lycomings have turbochargers (compressor, etc.) on them? The hot exhaust gasses drive the compressor just like on jets, and it has a prop (unducted fan).

I never suggested this. The engine would still be a reciprocated piston engine and not a gas turbine.

Operational consideration: Do jets and turbo-fans generally have longer spool up times?

Propellers have better acceleration principles (in both respects) and are therefore easier to manage, apparently arguable. Which would be the reason for the experience distinction IMhO.

Ok x-wind, spool time and acceleration is reasonable.

Should anyone really care? Not in my opinion. An HS748 or CV580 demands more from a pilot than say a slowtation and a non turbine powered C46 demands more than all three.

This is why a quick review of types flown will give someone a better snap shot of experience, rather than a number in a column.

I agree, but still, I've seen job adds that specifically require "jet" time...

When a jet engine fails, you're not scrambling to feather the inlet compressor fan blades

No your not, which is another reason why turboprop operations are more complex.

So why is "jet" time held in higher regard?
So far:
-fly higher
-fly faster
-longer spool time
-slower acceleration

[Strega]

oh yeah what about this guy...lol

Damn!

you beat me to it!

S

[crooked timber]

I've seen job adds that specifically require "jet" time...

the disambiguation lies within this context. when an operator is looking for "jet time" (turbofan), they're looking for someone who has experience dealing with the things Panama Jack alludes to (vis-a-vis handling the big jets). as mentioned, some of these considerations are: swept wing characteristics, high alt operation (mach tuck, ozone exposure, etc), flying around jet streams, mountain wave (which becomes a bigger deal when you're snuggled up in the coffin corner), low energy handling, fms experience and international ops. none of these things require any kind of superpowers but if a company is looking to hire someone who they can upgrade quickly then there is value in this type of prior experience.

[wilton]

it seems to me that you are trying to "UP or PAD" your log book. Turbo-prop is not Jet time.

[wallypilot]

Turbofan's produce it's primary thrust through the turbine and exhaust. Yes the compressor blades (not propellers), produce some thrust through the bypass fan inside the shroud, but it's not the primary source of it.

That's true of lower bypass engines, but many high bypass engines today, that's not always the case. The CF34B produces about 80% of it's thrust from bypass air at low altitudes, and at high altitudes, it's about 80% core thrust.

[wallypilot]

So why is "jet" time held in higher regard?

It's not held in higher regard(necessarily). It's what's important for an employer hiring to fill a position on a jet. There are many jobs where jet time is not really relevant.

FWIW, it takes some time to get used to handling a jet. it's different than flying turboprops. I'm not saying it's more difficult. it's not. As a matter of fact, once you've adjusted to it, it's easier. But there's a lot more stuff to consider that if you come from a turboprop background (as most of us do) you just don't think about in a turboprop, and they are things that can bite you. For example, lower speed maneuvres like circling to land are so much different in a jet than in a turboprop. Speed/momentum/spool up time all have to be considered. I found that a turboprop(can't speak about the big ones like DHC-8, 580, etc), was much easier to handle safely in such maneuvres.

[flying4dollars]

Turbofan's produce it's primary thrust through the turbine and exhaust. Yes the compressor blades (not propellers), produce some thrust through the bypass fan inside the shroud, but it's not the primary source of it.

That's true of lower bypass engines, but many high bypass engines today, that's not always the case. The CF34B produces about 80% of it's thrust from bypass air at low altitudes, and at high altitudes, it's about 80% core thrust.

You're right. I stand corrected.

[flying4dollars]

No your not, which is another reason why turboprop operations are more complex.

So why is "jet" time held in higher regard?
So far:
-fly higher
-fly faster
-longer spool time
-slower acceleration

Jet time is not held in higher regard necessarily. Jet operators like jet time from their applicants because it relates to their operation. Just like going to a company that operates all turboprops like turbine (turboprop) time. I think that for many people, jet jobs are the pinnacle of their aviation careers. This is how we perceive it anyways. It's really in the eyes of the beholder. Someone may consider flying a corporate B200 the pinnacle of theirs. To each their own.

[Hedley]

it takes some time to get used to handling a jet

Not much.

IMHO the jets I fly are a lot easier and simpler than the C421B I also fly, and have considerably lower workload on both departure and arrival. Better air conditioning, too!

On arrival, if I want to kill some altitude in the jet, I just pull the throttle back to flight idle and thumb the boards out. I sure can't do that in the 421 - I need to plan my arrival a lot more carefully!

Jet operators like jet time from their applicants because it relates to their operation

Exactly! For example, I have never flown a turbo-prop - I have no interest in them. I don't know a PT6 from a Garrett. So, I would reasonably expect that a (turboprop) King Air operator would have no interest in someone like me, even though I fly turbofan jets.

[eeffoc]

You're right. There still does seem to be a perception that jets are held in higher regard than turboprops. From a pilots perspective once you've flown a jet its not a big deal anymore. Its all about your experience and what you perceive. I do think its the non pilot public that pushes the jet onto the pedestal because props are just old technology to them. Of course we are somewhat influenced by what the public thinks of our industry.
A high bypass turbofan is a bit like a turboprop in some ways. Its is a ducted fan which is like place a shroud around the props of a turboprop. Turboprops are unducted fans, just look at the Q400 with six large prop blades. They still have different operating characteristics though, which makes each design unique

[Gino Under]

ETOPS
In response to your questions, with an apology for its length.
(and with reference to Pratt&Whitney's "Gas Turbine Engine-and its operation")

Q) Does turbofan time count as "jet" time?
A) Yes.

Correctly speaking, the name, jet engine, is slang when applied to turbine type engines for aircraft. Such engines are more properly called gas turbine engines. Nevertheless, the two names are synonymous and interchangeable.
A turboprop is a jet engine.
A turbofan is also a jet engine.

At first glance, the term, gas turbine engine, might be misleading. Because the word, gas, is so often used for gasoline, one might think that the reference is to a turbine engine that used gasoline for fuel. The name, however, means exactly what it says: a turbine type engine that is operated by a gas rather than one operated, for instance, by steam or water. The gas which operates the turbine is the product of the combustion that takes place when a suitable fuel is mixed and burned with air passing through the engine. In most gas turbines (jets), the fuel is not gasoline at all, but rather, a low-grade distillate such as military JP-4 or a blend of commercial kerosene that meets special requirements.

Q) Does "turbine" time incorporate all three groups (prop, fan, jet), or does it just refer to turboprops?
A) Yes. And No.

Gas turbine engines (jet engines) for aircraft are many and varied, and they are produced in many sizes. Jet engines have been subdivided into four configurations: turbojet, turbofan, turboprop, and turboshaft.

TURBOJET- an aircraft gas turbine engine (jet engine) that uses only the thrust developed within the engine to produce its propulsive force.

TURBOFAN- a turbofan (called a fanjet by some commercial airlines) is much like a turboprop except that the ratio of secondary airflow (the airflow through the fan or propeller) to the primary airflow through the basic engine is less. (This is called the bypass ratio.) Also, in the turbofan, the gear-driven propeller is replaced by a duct-enclosed, axial flow fan with rotating blades and stationary vanes which are considerably larger but otherwise similar to the blades and vanes of an axial flow compressor.

TURBOPROP and TURBOSHAFT- an aircraft gas turbine engine (jet engine) that uses exhaust gases from the basic part of a turbojet (often called a gas generator) and is used to rotate an additional turbine that drives a propeller through a speed-reduction gear system. The British and some commercial airlines call such engines a propjet.

I’ve looked through my logbooks and I have no separate column in any of them to add my Turbine time, so I total my turbine time separately. I'm not sure what others do. I recently bought a computer logbook which does include Turbine time entries for ease of separation, but, it’s going to take many months to enter the data from my paper logbooks and I don’t know if I’m going to waste that kind of time. I'll see what the wife thinks.
What do I do as far as logging my hours?

I have PT6, JT9, JT8, CF6, and CF34 time which is all jet time. If you asked me if I have jet time, I'd tell you, yes. If you asked me whether that jet time included turboprop time, I'd say yes. How much? Whatever my total time on a particular Turboprop is, is my turboprop time. If I was asked for turbofan hours, I'd simply total my JT9, CF6 and CF34 time to come up with the answer. If I was asked for my turbojet time, I'd give my B737 Classic time as the answer. So it's easy to account for your jet time however you break it down. An intelligent pilot knows what jet time is. If someone asked you for your jet time and you included your PT6 time, should the response be "that's not jet time, that's turboprop", I'd question the questioner's knowledge and understanding of jet time. Wouldn't you?

Make sure the person asking you if you have any jet time makes it clear what kind of jet time he/she are asking you about. Remember there are four subdivisions of jet engines.

I'm sure you already know most of this information but you can easily tell from many of the answers you've received that many pilots are themselves still confused over what is and what isn't jet time. I hope you find this information helpful?

Gino

[ETOPS]

I appreciate the post Gino.

[ftp]

Also consider how you are judging engine output.

Turboprops - Torque or % of max torque

Turbofans/Jets/Millenium Falcon - EPR (Exhaust pressure ratio) - Difference in air pressure leaving the engine compared to entering the engine.

[fingersmac]

What do I do as far as logging my hours?

I have PT6, JT9, JT8, CF6, and CF34 time which is all jet time.

All I have is PT6 and RDa.7 time. I would look mighty foolish showing up to an interview claiming I have jet time. Semantics aside, the safest approach to logging jet time is to only include turbofan and turbojet time. After all, the only one who cares is the employer specifying it in their job ad. 'Flying4dollars' alluded to it earlier, if a company asks for jet time it's because they want relevant experience to their operation and the aircraft types they fly.

[Ogee]

One quesiton which arises is ... why does it matter?

If you're looking for employment, you will normally list types flown. If your prospective employer needs to make such a distinction, and can't make it by aircraft type...well, what does that tell you?

[Gino Under]

Aviation is full of semantics.

I answered the question by simply breaking out the four types of jet engines. Operating any one of those four types IS jet time.
That said, I completely agree with your comment. If an employer is looking for "jet" time and all you have is PT6 time, IT'S STILL JET TIME for the logbook. But, it may not be what an employer may have in mind if all they operate are B727s, or DC10s.

I know it's stating the obvious, but if they want jet time and know themselves what kind of jet time they're looking for, they will likely know from your application or at least ask if any of your "jet" time happens to be on a 727 or DC!0.

If an employer is going to sit me down and ask me a technical quiz they should at least know what a jet engine is themselves. Right?

Kind of like someone pointing out or refering to number (b).
B is a f***in' letter.
Right?.

Gino Under

[skyhigh]

Oh for f$@k sakes people. If you have propellers on your airplane, it AIN'T a jet!! And for the the record i do like flying the B737ng better than any of my old "prop" airplanes which included the dash 8.

[ETOPS]

Thats awesome skyhigh.
Here's a sticker for your rear bumper:

[skyhigh]

Yeah thats ok, would have prefered JETJOCK

[AuxBatOn]

Gino, you may want to revisit your definition of "Jet".