Question for Bob Gardner - Multiengine bank angle

[kevmor]

I just finished reading the Jeppesen "flight discovery" series for
their Multiengine manual, and just started reading the ASA's The
Complete Multiengine pilot. I noticed in their book that they
mentioned several times that, for best performance, you don't need 5
degrees of bank that planes are tested at. It stresses to use less,
such as 2-3 deg. depending on the plane. I noticed in your book (pg.
1-5) it says "at least 5 degrees"...which is correct? I'd have to
check the Jeppesen one again, but I think they tested climb rates with
different bank angles to figure the best one.

[Luke Skywalker]

On May 11, 10:27 pm, kevmor > wrote:
> I just finished reading the Jeppesen "flight discovery" series for
> their Multiengine manual, and just started reading the ASA's The
> Complete Multiengine pilot. I noticed in their book that they
> mentioned several times that, for best performance, you don't need 5
> degrees of bank that planes are tested at. It stresses to use less,
> such as 2-3 deg. depending on the plane. I noticed in your book (pg.
> 1-5) it says "at least 5 degrees"...which is correct? I'd have to
> check the Jeppesen one again, but I think they tested climb rates with
> different bank angles to figure the best one.

I would be interested in the answer, but several years ago we did test
with a Twin Comanche and found that the "number" is 2-3 depending on
the CG. However one thing we did find when we went out of the realm
of "professional pilots" (ie flight test pilots) and into the realm of
competent but "normal levels of currency" pilots (ie multi engine
pilots who flew around 100 hours a year) that 5 degrees was a good
goal to shot for. It was easy to see on the "ADI" (attitude gyro) and
steading on that gave really good performance.

I have the numbers somewhere (it was a contract for Piper) but the
bank does make a difference the largest difference is correct
operation of the rudder (IE putting the ball in the correct
position). 100-200 fpm might not seem like much...

but

Robert

[Jim Burns[_2_]]

Initial bank of at least 5 degrees, no more than 10 degrees, to maintain
directional control while pitching to Vyse, THEN use a bank of approximately
2 degrees after Vyse is established to obtain maximum climb performance.
Control before performance.


From the FAA handbook,
http://www.faa.gov/library/manuals/aircraft/airplane_handbook/media/faa-h-8083-3a-5of7.pdf
page 12-25.


To maintain directional control of a multiengine
airplane suffering an engine failure at low speeds

(such as climb), momentarily bank at least 5°,

and a maximum of 10° towards the operative

engine as the pitch attitude for VYSE is set. This

maneuver should be instinctive to the proficient

multiengine pilot and take only 1 to 2 seconds to

attain. It is held just long enough to assure directional

control as the pitch attitude for VYSE is

assumed.

.. To obtain the best climb performance, the airplane

must be flown at VYSE and zero sideslip,

with the failed engine feathered and maximum

available power from the operating engine. Zero

sideslip is approximately 2° of bank toward the

operating engine and a one-third to one-half ball

deflection, also toward the operating engine. The

precise bank angle and ball position will vary

somewhat with make and model and power

available. If above the airplane's single-engine

ceiling, this attitude and configuration will result

in the minimum rate of sink.



Jim

[Jim Macklin]

The 5° bank angle is in the Part 23 regulations for aircraft
certification and only considers a limitation on stopping
the turn. A steeper bank can stop a turn if you are below
Vmca and are sloppy enough to have lost control. But 5° is
just a limitation on the certification test pilot. The bank
angle reduces the need for more rudder which the design may
not have. There is also a limit of 150 ponds of rudder
force, which can be done pretty easily by a man, but may be
harder for a 100 pound woman. But the is aircraft
certification.

The 2-3° bank is for zero sideslip and maximum climb
performance. It will vary with aircraft make and model and
operating weight. The point is too have zero yaw angle so
the drag is as low as possible and get the maximum climb
rate.



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

"kevmor" > wrote in message
ups.com...
|I just finished reading the Jeppesen "flight discovery"
series for
| their Multiengine manual, and just started reading the
ASA's The
| Complete Multiengine pilot. I noticed in their book that
they
| mentioned several times that, for best performance, you
don't need 5
| degrees of bank that planes are tested at. It stresses to
use less,
| such as 2-3 deg. depending on the plane. I noticed in
your book (pg.
| 1-5) it says "at least 5 degrees"...which is correct? I'd
have to
| check the Jeppesen one again, but I think they tested
climb rates with
| different bank angles to figure the best one.
|

[Bob Gardner]

As the two Jims have pointed out (thanks, guys), there are two issues here:
retaining control at the time of failure and best climb performance after
the airplane is cleaned up. "At least five..." applies in the first
instance, and "..two to three..." in the second. I still run into
articles/books where the "not more than..." is supposed to apply to Joe
Sixpack, not the factory pilot. Sheesh!

Bob Gardner

"kevmor" > wrote in message
ups.com...
>I just finished reading the Jeppesen "flight discovery" series for
> their Multiengine manual, and just started reading the ASA's The
> Complete Multiengine pilot. I noticed in their book that they
> mentioned several times that, for best performance, you don't need 5
> degrees of bank that planes are tested at. It stresses to use less,
> such as 2-3 deg. depending on the plane. I noticed in your book (pg.
> 1-5) it says "at least 5 degrees"...which is correct? I'd have to
> check the Jeppesen one again, but I think they tested climb rates with
> different bank angles to figure the best one.
>

[kevmor]

Thanks all!

On May 12, 8:43 am, "Bob Gardner" > wrote:
> As the two Jims have pointed out (thanks, guys), there are two issues here:
> retaining control at the time of failure and best climb performance after
> the airplane is cleaned up. "At least five..." applies in the first
> instance, and "..two to three..." in the second. I still run into
> articles/books where the "not more than..." is supposed to apply to Joe
> Sixpack, not the factory pilot. Sheesh!
>
> Bob Gardner
>