Why are multiple engines different?

Jim, I need help. What are vmca and vmcg?
--and with regard to Vmc, I thought that that was the minimum
controllable airspeed with one engine not operating and the other one
at full power. With reduced throttle on the operating engine, Vmc goes
down. So in the case of a landing aircraft, it is actually possible to
approach and rotate below Vmc without loss of controll. The closer you
get to a deadstick landing, the lower the rotation speed could be.
Obviously there are reasons not to do this--I am just commenting on
control issues. But please help me on vmca and vmcg.

Jim Macklin wrote:
The first speed that comes to mind should be reprogrammed to
be Vyse, you'll live much longer.



If you look at an old multiengine manual, such as the Beech
BE 95-55 they advertised very short take-off and landing
distances and the plane will do them. But you would rotate
10 knots below Vmc and fly the final at about Vmc. If the
engines were running, no problem. Loss of an engine meant
almost immediate crash unless you were very quick and lucky.

Modern POH says, rotate at not less than Vmc+5, accelerate
to Vxse-Vyse quickly. Gear remains down until Vyse or
you're out of runway to land straight ahead or you reach
circling minimums. On landing, maintain Vyse until landing
assured.






"Emily" wrote in message
. ..
| Jim Macklin wrote:
| I didn't mean to say that either. Vmca (Vmcg too) are
very
| important, but Vyse is the first performance number for
a
| light twin [along with Vxse], similar to V2 for a
transport
| category aircraft.
| Vyse is shown by the blue line and that is the target
| airspeed.
|
|
| I have a multi rating, thank (two of them, actually).
|
| I was simply throwing out the first airspeed that came to
mind.

Mxsmanic wrote:

sparingly.

So how many hours a month does the average private pilot actually
spend with the prop turning?

It depends. The problem I have had was that either I could
afford to fly a lot, but didn't have the time; or had plenty
of time but could no longer afford it. Eventually it evens
out. Ideally, I'd like someone else to foot the bill, that's
what I am working on these days :-)

--Sylvain

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.

Vmca is the airborne speed that is what most people thing of
when you mention Vmc. Reduction in power lowers the speed
as does having the downward prop blade being close to the
fuselage. But when Vmca is close to or at Vs, loss of
heading and the stall happen at the same time, that leads to
a spin.
Closing the throttles regains control since there is no Vmc
without the asymmetric power. But the pilot must be willing
to cut power and dump the nose to a glide attitude or a
stall will happen and that leads to crashes. Even in a
single, after an engine failure on take-off, with the nose
5-15 degrees above the horizon you must push the nose down
to 2 or 3 degrees below the horizon or it will stall too.
But once you do that to retain control in a twin, you can
fly away to a crash site of your choice, often back to the
airport for an emergency landing.

To get the benefit of a twin, you plan for an engine failure
all the time and only fly in the critical parts of the
envelope when you have other options. On take-off, abort
for any indication below Vmca. After that, rotate at Vmc+5
and accelerate to Vyse. Don't retract the gear if there is
runway ahead you can land on (below 50 feet, you need about
4000 feet in Duchess) if you have practiced an airborne
abort before.
Once you have run out of runway and retracted the gear get
to circling minimums (400 feet) ASAP.
Remember Vyse is the speed target that allows you to
take-off or approach and land with a margin. When landing,
approach at Vyse allows a safe go-around. Once landing is
assured, you will reduce power and land.


--
James H. Macklin
ATP,CFI,A&P

"swag" wrote in message
ups.com...
| Jim, I need help. What are vmca and vmcg?
| --and with regard to Vmc, I thought that that was the
minimum
| controllable airspeed with one engine not operating and
the other one
| at full power. With reduced throttle on the operating
engine, Vmc goes
| down. So in the case of a landing aircraft, it is
actually possible to
| approach and rotate below Vmc without loss of controll.
The closer you
| get to a deadstick landing, the lower the rotation speed
could be.
| Obviously there are reasons not to do this--I am just
commenting on
| control issues. But please help me on vmca and vmcg.
|
| Jim Macklin wrote:
| The first speed that comes to mind should be
reprogrammed to
| be Vyse, you'll live much longer.
|
|
|
| If you look at an old multiengine manual, such as the
Beech
| BE 95-55 they advertised very short take-off and landing
| distances and the plane will do them. But you would
rotate
| 10 knots below Vmc and fly the final at about Vmc. If
the
| engines were running, no problem. Loss of an engine
meant
| almost immediate crash unless you were very quick and
lucky.
|
| Modern POH says, rotate at not less than Vmc+5,
accelerate
| to Vxse-Vyse quickly. Gear remains down until Vyse or
| you're out of runway to land straight ahead or you reach
| circling minimums. On landing, maintain Vyse until
landing
| assured.
|
|
|
|
|
|
| "Emily" wrote in message
| . ..
| | Jim Macklin wrote:
| | I didn't mean to say that either. Vmca (Vmcg too)
are
| very
| | important, but Vyse is the first performance number
for
| a
| | light twin [along with Vxse], similar to V2 for a
| transport
| | category aircraft.
| | Vyse is shown by the blue line and that is the
target
| | airspeed.
| |
| |
| | I have a multi rating, thank (two of them, actually).
| |
| | I was simply throwing out the first airspeed that came
to
| mind.
|

It always take 3 things to get anything done. Desire, money
and time. It is easy to get any 2 of the 3.



"Sylvain" wrote in message
...
| Mxsmanic wrote:
|
| sparingly.
|
| So how many hours a month does the average private pilot
actually
| spend with the prop turning?
|
| It depends. The problem I have had was that either I
could
| afford to fly a lot, but didn't have the time; or had
plenty
| of time but could no longer afford it. Eventually it
evens
| out. Ideally, I'd like someone else to foot the bill,
that's
| what I am working on these days :-)
|
| --Sylvain

("Jim Macklin" wrote)
It always take 3 things to get anything done. Desire, money and time.
It is easy to get any 2 of the 3.


The Cowboys (1972) ...John Wayne

When our group of cow(boys) happen upon a wagon full of giggling young
(future madams) who are heading to 'the next town over' to set up shop,
the two adults at the scene decide ...these cow(boys) don't have the
money, anyway. And besides, Mr's Collingwood laments, "The first time
should be in the back of a buggy with a girl that they think they're in
love with."

She then casts her eye our trail boss, Mr Nightlinger, to which he
politely declines, stating, "Well, I have the inclination, the maturity,
and the where-with-all; but unfortunately, I don't have the time."

Roscoe Lee Browne
Colleen Dewhurst


Montblack
I love that scene!

Sylvain writes:

It depends. The problem I have had was that either I could
afford to fly a lot, but didn't have the time; or had plenty
of time but could no longer afford it.

I note that this general rule applies to all sorts of things, not just
flying. You can have money or you can have time, but it's extremely
difficult to have both.

Bill Gates was once asked what he wanted most, given that he had
enough money to buy just about anything, and even he answered, "Time."

Eventually it evens
out. Ideally, I'd like someone else to foot the bill, that's
what I am working on these days :-)

You plan to become a commercial pilot or something?

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

Ron Natalie wrote:
Mxsmanic wrote:
Emily writes:

Uh, no. Look up "single engine service ceiling" please.

I already have. The single-engine ceiling for the Baron I prefer in
the sim is about 8000' MSL, as I recall, which is enough for almost
all the flights I take. I do occasionally fly over mountainous
regions, but I'd be much more hesitant to do so in real life.

Better yet, actually GO FLY something.

I'll just win the lottery and run right over the airport.

Sell your computer and simulator. That should be good for
a couple of hours.

Spend the time you do vegetating in front of the simulator
reading some aviation books and exercising. It will do better
for you in the long run.

Could you imagine this guy in a Baron?

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...

--Sylvain

Mxsmanic wrote:

You plan to become a commercial pilot or something?

I already am a commercial pilot, what I am hoping for
is to get paid for it :-)

it's like looking for a job (engineering): it is really
easy I found out, what's more tricky is to get paid :-)
Liz Phair has a really nice song on the subject :-)

--Sylvain

Some can, easily.

Karl

"Sylvain" wrote in message
t...
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...

--Sylvain