Question on Baron 58 prop control

Allen writes:

As Jim said the PW PT6 engine has no physical connection between the power
section and the drive section.

How does power get from one to the other?

--
Transpose mxsmanic and gmail to reach me by e-mail.

Mxsmanic wrote:
How does power get from one to the other?


The turbine's output over a second series of fan blades, which are
connected to the propeller shaft. In effect, it's a giant torque
converter (if you're at all familiar with car technology).

In fact, you can hold, with your bare hand, the prop blade during start
up. Just don't let go of it, and don't try to catch it if it comes
loose! (Oh, and RUN!)

Is a feathered prop
always edge to the wind, or flat to the wind

Edge to the wind. The thought is that the engine has already failed in
some capacity, and a windmilling prop causes massive cavitation and
drag, so the blade edge is aligned with the relative wind to stop it
from turning (although not fully, due to mechanical positioning issues,
they get really, really close).

"TheSmokingGnu" wrote in message
...
Mxsmanic wrote:
How does power get from one to the other?


The turbine's output over a second series of fan blades, which are
connected to the propeller shaft. In effect, it's a giant torque converter
(if you're at all familiar with car technology).


Interesting. Is that what gave rise to the old slang term "Propjet"?

How does this compare with the present form of propulsion, such as in the
B747, which I've heard being called "Fanjet"? Is it the same but turbine
blades replace propellor blades while serving a similar function?

Barrie

Barrie writes:

How does this compare with the present form of propulsion, such as in the
B747, which I've heard being called "Fanjet"? Is it the same but turbine
blades replace propellor blades while serving a similar function?

Essentially, yes. A turbofan is a jet engine with a very large front
fan in a duct. This fan, which is driven by a turbine in the
combustion section that in turn is driven by hot exhaust gases,
provides most of the thrust. It's like a many-bladed propeller in a
duct (whence the term "ducted fan," which is occasionally used). It's
much more efficient than a pure turbojet, and it also has advantages
over an open prop. It's the preferred mode of propulsion for
commercial airliners these days.

However, turbofans don't work well at transonic and supersonic speeds,
although I understand that these problems have been fixed in recent
years. Likewise, they don't have significant advantages for low speed
flight like that of a small GA plane.

--
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Mxsmanic wrote:

However, turbofans don't work well at transonic and supersonic speeds,
although I understand that these problems have been fixed in recent
years. Likewise, they don't have significant advantages for low speed
flight like that of a small GA plane.

Turbofans work very well at transonic & SS speeds. The engines in the
F-15, F-16, F-18, F-22, F-35 (you get the idea) are turbofans (w/
afterburners). The F-22 engines are so efficient they allow supersonic
flight without the burners lit (supercruise) The difference is they are
low-bypass turbofans compared to the big high-bypass engines on
transport category aircraft - (Boeing, Airbus)

Turbines burn lotsa fuel at low altitudes and are most efficient at
high alts, which normally requires pressurization. Your typical GA
plane doesn't fly at high enough altitudes to get the most benefit from
turbine power.

"Kingfish" wrote

Mxsmanic wrote:

However, turbofans

Turbines burn lotsa

You had to give in to the dark side, huh?

So sorry. :-(
--
Jim in NC

"Mxsmanic" wrote in message
...
Allen writes:

As Jim said the PW PT6 engine has no physical connection between the
power
section and the drive section.

How does power get from one to the other?

air pressure

Air mass
"BT" wrote in message
...
|
| "Mxsmanic" wrote in message
| ...
| Allen writes:
|
| As Jim said the PW PT6 engine has no physical
connection between the
| power
| section and the drive section.
|
| How does power get from one to the other?
|
| air pressure
|
|