Why are multiple engines different?

karl gruber wrote:

Some can, easily.

light twins?

--Sylvain

Sylvain wrote:
Jim Macklin wrote:

Vmcg is the speed where you can't maintain heading with the
critical engine failed and there is not enough rudder or
tire steering. Yaw is most severe at low speed because the
rudder is ineffective and some airplanes have steering
problems with tire geometry.

by the way, that's one of the things that MS FS gets
wrong with the light twins: with a long enough runway you
can takeoff with only one engine...

What, you mean that's NOT how it works in real life? Surely MSFS didn't
get something wrong....

karl gruber wrote:
Some can, easily.

Name one light twin that can take off on one engine.

Note: a 737 is not considered a light twin.

Mxsmanic wrote:
cjcampbell writes:

A turborprop
increases safety, but now you are talking real money, both in
acquisition cost and in fuel and maintenance.

Why are turboprops so much more expensive? I thought gas turbines
were supposed to be simpler and more efficient.

They are simple, but much less efficient than piston engines. Every
teaspoon of fuel has a fixed number of calories. Efficiency is measured
by what percentage of these calories is translated to thrust. The
reason turbines generate so much power despite their inefficiency is
that they can burn a lot more fuel even though they waste much of the
energy in the fuel. The inefficiency translates into incompletely
burned fuel, waste heat, exhaust, and pollution. Basically, this means
that you have to burn more fuel to generate 100hp in a turbine engine
than you do in a piston engine. A jet engine loses even more efficiency
in the translation of hp to thrust. A turboprop is more efficient than
a pure jet because of its propeller, but it still is not as efficient
as a piston engine. Turbines will probably never be as efficient as
piston engines. This is why gas turbine automobiles have never become
popular. People don't want a car that gets less than 10mpg unless it is
a Rolls Royce. Plus, acceleration is terrible. Chrysler built a batch
of gas turbine concept cars back in the early '60s and lent them to
ordinary consumers as a test. People hated them, not least because of
the annoying, high-pitched whine. I remember seeing them at car shows
back then. But, hey: it would burn anything -- gas, diesel, jet fuel,
vegetable oil, even perfume (and how long will it be before the price
of gas approaches that of perfume, either as fuel or otherwise -- and
what is it with cars and perfume, anyway?).

The reason we use jet engines is that they are inherently more powerful
and they can operate at high altitudes where the efficiency penalty
compared to piston engines is less. At high speeds, drag is a more
important factor in fuel economy than engine efficiency, so jet
airliners get their best fuel economy at high altitude. But for short
hauls where it would just be a waste of fuel to climb to high altitude
and descend again, a turboprop will deliver more power than a piston
engine with greater fuel economy than a jet.

karl gruber wrote:
"cjcampbell" wrote in message
ps.com...
Once you get into turbo-props you start flying above the weather
(unless you are flying some non-pressurized turbo-prop) and have much
more reliable engines. This eliminates a lot of the problems found in
piston aircraft.


And, the vast majority of turbo-props are flown by professional pilots with
regular training.

Exactly. Not too many bozos out there buzzing their girlfriend's house
in a turboprop.

Mxsmanic wrote:
cjcampbell writes:

There is a considerable difference between multi-engine and single
engine flying. Engine failure is only the beginning. Fuel systems are
much more complex, as are electrical and other systems. It affects even
the cabin heating system. Even taxiing is significantly different.
Neither is is just a few procedures for the failure of an engine; the
fact is that an engine failure in a twin will have you over on your
back in seconds if you don't watch it. This is especially true in the
Beech 58.

The trouble with flight simulators is that they don't really feel like
airplanes. If you want to simulate an engine failure with your Beech
58, try this: turn the heat in your living room all the way up, but
pack your feet in bags of ice. Take a several cold tablets so that you
are feeling dizzy and disoriented. Have a screaming two-year old
kicking the back of your chair while a couple goons shake your chair
back and forth. Without warning, two more goons will grab your controls
and try as hard as they can to turn them in the direction of the failed
engine, while your own arms and hands are tied to the arms of the
chair. Another goon will bounce your monitor up and down very rapidly
until it breaks, and all the time the stereo will be turned up as loud
as it will go with engine noise and a controller constantly giving you
instructions. All that will not be quite as tough as a real engine
failure, but it is a start.

So I have the same question as Mark: Why do people buy or fly twins
if they are so horrible compared to singles?

A lot of the time it just gets down to people having more money than
sense.

cjcampbell wrote:
Mxsmanic wrote:
cjcampbell writes:

A turborprop
increases safety, but now you are talking real money, both in
acquisition cost and in fuel and maintenance.
Why are turboprops so much more expensive? I thought gas turbines
were supposed to be simpler and more efficient.

They are simple, but much less efficient than piston engines.

Plus, parts are a lot more expensive and when things go very bad, the
maintenance costs are a lot more than a piston. That alone scares a lot
of operators off.

Ok, actually, I don't know much about turboprops, but that's the case
for turbofans.

Emily wrote:
cjcampbell wrote:
Mxsmanic wrote:
cjcampbell writes:

A turborprop
increases safety, but now you are talking real money, both in
acquisition cost and in fuel and maintenance.
Why are turboprops so much more expensive? I thought gas turbines
were supposed to be simpler and more efficient.

They are simple, but much less efficient than piston engines.

Plus, parts are a lot more expensive and when things go very bad, the
maintenance costs are a lot more than a piston. That alone scares a lot
of operators off.

Ok, actually, I don't know much about turboprops, but that's the case
for turbofans.

From a maintenance standpoint, just think of a turboprop as being a
turbofan with a lot less blades.

Emily wrote:

What, you mean that's NOT how it works in real life? Surely MSFS didn't
get something wrong....

you mean that I can go ahead and fly inverted under
the Golden Gate for real? wheeeeee! looking forward
to the upcoming weekend! :-)

--Sylvain

All I can say is ...........I've seen it. Name some light twins. If you can
come up with the right one, you win the big prize.

Karl
"Curator" N185KG
CFI MEA&I
ATP BE300 CE500 LR-JET DA50
Helicopter

"Emily" wrote in message
. ..
karl gruber wrote:
Some can, easily.

Name one light twin that can take off on one engine.

Note: a 737 is not considered a light twin.