Piper Seneca
My real world '66 C, non turbo Aztec numbers are identical to Ronnie's.
Recent 25 hour round trip flight from WI to Las Vegas and back yielded an
average of 22 gph fuel burn at TAS between 160 and 165. I also flight plan
on 160 TAS at 25gph.
Jim
"Ronnie" wrote in message
. com...
Frode,
For my 1964 C model, non-turbo Aztec:
Gross Weight: 5,200 lbs Empty Weight: 3,120 lbs Useful Load: 2,080
lbs
Payload w/ Full Fuel 1,240 lbs
Total Fuel: 144 gallons Usable Fuel: 140 gallons
Payload with full fuel: 1,240 lbs
Normal cruise Performance: 160 KTAS @ 7,000 MSL @ 24 GPH
Endurance: 5.8 hours
Range: 928 NM
The flight manual indicates that the maximum cruise speed is 178 knots at
7,000' to 8,000' and 75% power.
I have found this to be optimistic. I flight plan for 160 knots with a
fuel
burn of 25 GPH. In flight, I see
true airspeeds ranging from 160 to 165 knots and at the pumps the fuel
consumption normally turns out
to be around 22 GPH. Using 160 knots and 25 GPH is conservative and it is
easy to do the math for fuel
burn in your head.
If you'd rather save fuel, extended your range and endurance, and log more
multi-engine hours, just pull
the power back. On a recent flight at 3,500', I decided to use 2,000 RPM
and 18" of manifold pressure and
see what the speed and fuel flow would look like. The true airspeed was
around 135 knots and the fuel flow
was 15 gallons per hour. On a 425 NM trip, the calculated difference in
time en route was 30 minutes, turning
what would have been a 2 hour, 40 minute trip into a 3 hour, 10 minute
trip.
The difference in the calculated
fuel consumption was 58.4 gallons versus 47.2 gallons, or a savings of
11.2
gallons. An added benefit of lower
power settings is that the airplane is quieter and the engines are loafing
along and running very cool.
Flight Speeds and Characteristics:
SPEED MPH
KTS
Vso 68
59
Vs 72
63
Vmc (Red radial line) 80 70
Vr (Vmc + 5) 85
74
Vxse 97
84
Vyse (Blue radial line) 102 89
Vx 107
93
Vy 120
104
Vfe 125
109
Va (@ 4800 lbs) 145
126
Vle 150
130
Vcruise 184
160
Vne 249
217
You have to look at the flight manual to get the various performance
figures, but on average
you will experience climb rates of between 1,400 to 1,900 FPM on a
standard
day from 4,000 lbs
up to full gross weight. With my normal load and on a hot summer day
leaving a 782' MSL field
using a cruise-climb airspeed of 130 MPH, I'll average 750 to 1,000 FPM as
the initial rate of
climb. At light weights and under cool conditions, using Vyse, it is not
hard to peg the
+2,000 FPM limit on the vertical speed indicator. This is of course with
both engines running.
A healthy rate of climb provides a quicker trip up to the cooler, smoother
air where you and
your passengers will be more comfortable.
The single-engine rate of climb is much less. Rate of climb is dependent
on
power in excess
of that necessary for level flight. When you lose an engine, you lose 50%
of your total power,
but in the order of 80% of your excess power. Therefore your climb
performance also suffers
by that same 80% figure. The flight manual shows a single-engine rate of
climb of between
225 and 625 FPM depending on weight for sea level, standard day
conditions.
Many people
are afraid of twins because of this poor single engine performance and the
potential for loss
of control after an engine failure on take-off. But consider the climb
performance of a single
engine airplane after loosing one engine! I'll guarantee you it will be
less! The most critical
time period in a twin for losing an engine is the few seconds between
rotation and getting to
a safe maneuvering altitude. There is an elevated risk of losing control
of
the airplane during
these critical few seconds of flight. This risk it managed by good
initial
training, good recurrent
training, and by proper planning and preparation before each and every
take-off. If you are well
trained, well practiced and have thought through the possibilities before
each take-off, you
should have no difficulty executing the manufacturer's engine-out
checklist
procedures and
maintaining control of the airplane.
For other phases of flight, an engine failure is a non-event. Assume you
are cruising along at
8,000' and you lose one engine. Yes, it will get your attention, but
there
is no emergency.
Identify which engine failed, verify you have identified the correct
engine
as the failed one,
and then go through the steps to either fix the problem or to feather the
prop and secure the
engine. If you end up securing the failed engine, you continue to fly on
the remaining engine
and will only slowly drift down to the single-engine service ceiling.
This
is the altitude where
the rate of climb is less than 50 FPM. For the Aztec, the lowest
single-engine service ceiling is
5,000' and goes up to over 17,000' depending on initial take-off weight
and
remaining fuel load.
In short, unless you are in the mountains, the single-engine service
ceiling
will not likely be a
concern. Simply find an airport where repairs can be made and head that
way.
Similarly, a single-engine approach and landing is also a non-event. Fly
the airplane at Vyse
throughout the pattern, fly a bit wider than normal pattern to give
yourself
a little extra time,
and defer the use of full flaps until the landing is assured. Once full
flaps are deployed, don't
attempt a go around. If you need to go around, make the decision early in
the approach. If you
attempt a "low and slow" go around, you've put yourself back into a single
engine takeoff phase
of flight which should be avoided.
I am a firm believer that a twin-engine airplane is safer than a
single-engine airplane, hands-down,
assuming a well trained, competent pilot in command in each airplane. The
benefit to you is that
you will fly safer as will your family and other passengers.
All the data above is for a non-turbo model. Turbo-charged Aztec are also
common and will
of course post higher speeds up high and associated higher fuel burns.
Maybe Kyler will
post the data for his turbo Aztec.
Ronnie
"Frode Berg" wrote in message
...
hi!
Thanks for your input.
As I stated, this is not a short term consideration, as I do not
currently
hold an IR license, but will be getting one starting this summer.
My wife and I have been toying with the possibilities of getting a
vacational house in southern Europe, and I've been saying ok, but we'll
need a de-iced twin, and she agrees, so a lot of the job is done....
:-)
However, the Aztec idea is interesting.
What are the figures for this plane?
Loading capabilities? Speeds? Endurance/range?
Thanks,
Frode
"Ronnie" skrev i melding
. com...
Frode,
I know you asked specifically about a Seneca and if you
want a Seneca, a Seneca you should get. However, in the
meantime, you might consider another Piper twin, the Aztec.
Older versions can be had for much less and would let you
fly a twin and accumulate multi-engine time before ultimately
getting the Seneca that you want. I admit I'm a bit biased
since I've been flying 1964 C model Aztec for the last 7 years.
There was a very, very nice Seneca III hangared in the same
hangar as my Aztec and it made me conside trading for a Seneca,
stricly on apperances. However, when I began comparing useful
loads, single engine rate of climb, and over-all performance versus
cost to aquire, I decided the Aztec fit my needs much better. At
first, the blub seating and left side, low entry door looked like a
plus
for the Seneca that make getting passengers and big items in and out
easier
However, after taking a couple of trips the club seating turned out to
be problematic for my family with the kids bumping knees. In our case,
we like the forward facing seats and two large cargo areas fore and
aft.
better.
Just food for thought.
Ronnie
"Frode Berg" wrote in message
...
hi all!
This might be a silly question, but I am dreaming of owning, or
co-owning a Piper Seneca.
Not this year or next, but maybe within the next 10 years.
I have been browsing the aircraft for sale sites, and found planes
from
the 70's (Seneca II) selling for as low as $139K with about half time
remaining on the engines and props.
Anyone care to share the pro's and con's of the different models?
(I-V)
Obviously, I will not be able to afford a V, so far, only the II's
seem
accessible sort of.
Anything worth knowing about this model? Bad things?
Also, I understand maintenance will be about double of what I have now
(Arrow 180).
Any other traps to consider cost wise going for a twin?
Any other aircraft in the same price range that might be better
choices?
I'm looking for a piston certified for Icing conditions.
I also want a twin, as I'll be flying over mountains and have
nightmares
about engine out's in IMC and icing conditions over mountain
terrain.....
Thanks for any hints,
Frode
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