FLIGHT International,
104
262kt (205kt IAS) for 5001b/hr total
fuel flow (a specific of 0-52 n.m./lb).
This compares with figures published
in the manual, where, at this temperature, the best performance would
have been obtained at Flight Level
200.
Stalls are carried out between
15,000 and 10,000ft and, in each case,
trimmed at 1 • 4Vs, the anticipated
stall speed for our weight of 6,3831b.
It serves to indicate the negligible
change in trim with flap and no
apparent change in trim with undercarriage. There is just a minor noseup pitch as flaps cycle from up to
15° and from 15° to 45°. In the clean
condition and trimmed at 115kt IAS
with J 2 division aft trim, a pull-force
developed at 85kt IAS, with the onset
of some airframe vibration at the
stall warning at 83kt IAS. Full up
elevator and moderately heavy buffet
gave the elevator limited stall condition at 80kt IAS. Very similar results
are obtained with the flaps at 15°
and undercarriage down.
Trim is the same at 115kt IAS, but
in this case a pull force develops below 95kt IAS and stall warning occurs
at 82kt IAS, together with airframe
vibration. By 80kt IAS the pull force
is very heavy, with marked airframe
buffet, and the stall is elevator
limited at 78kt IAS. With undercarriage down and full flap again
there are similar results with an
elevator limited stall at 74kt IAS.
Docile stall
In all cases the stall is very docile
without any tendency for a wing to
drop. Recovery is immediate on easing the elevator. However, we are at
a forward e.g. in the region of
152-57in and elevator limited before
reaching the true stall.
The flight manual publishes a
VMCA of 90kt IAS with undercarriage
and flaps up, engine feathered and 5°
bank towards the live engine. In this
configuration at 10,000ft we get down
to 80kt IAS with full rudder deflection at maximum foot force but with
plenty of aileron in hand, and note a
spot climb rate in the region of 700ft/
min at our weight of 6,3331b.
The published single-engine rate of
climb at maximum weight in ISA at
teea-level is 424ft/min. It is to be
noted that this is reduced by 350ft/
min with undercarriage down and,
although the undercarriage retracts
quickly in 4-5sec, it does bring home
the value of autofeather. A simulated
engine failure on take-off with undercarriage down on a full power climb
at 98kt IAS is no handling problem,
and a positive rate of climb is obtained at 9,000ft. On retracting undercarriage and increasing speed to best
angle of climb speed 102kt IAS, a
spot rate-of-climb check shows some
600ft/min. The benefit of flat rating
shows up in the published singleengine ceiling of 19,000ft at maximum weight. It is a pity a slightly
more energetic single engine climb
is not available at sea level.
General handling is excellent, both
in symmetric and asymmetric configuration, especially at low speeds.
There is a nice but modest degree of
positive stability with speed. Both the
manual and electric trim rates are
right, and change in trim with power
is negligible.
In the cockpit the sound level is
very acceptable and in the air-conditioned cabin it is said to be a low
80 decibels. Just a little experimenting is required to find the best r.p.m.
for smoothest running. The view
from the cockpit is better than most,
and only in the maximum rate of
climb speed case at 115kt IAS does
the long nose intrude on forward
view.
What little instrument flying was
carried out implies a good and stable
platform, and the circuit handling is
very much "light aircraft," although
undercarriage can be taken at a high
175kt IAS, together with 15° of flap.
Final approach is made at 102kt IAS,
with a threshold speed of 95kt IAS
for our weight of 6,1291b. The trailing-link undercarriage gives a very
benign impression. Our ground roll
without propeller reversing should
have been some 700ft, and about
1,700ft from 50ft—possibly 200ft less
with reversing.
The well-equipped aircraft flown
has a basic weight of 5,3111b, and
with fuel tanks full (2,4521b/366 US
gal) the pay load is reduced to a
total of three persons. With all seven
seats occupied (excluding the occasional toilet seat), 1,7741b is available
for fuel. Between these two extremes
lies the typical executive payload of
four passengers and two crew plus a
baggage allowance of 1441b. This permits a fuel load of 1,8001b for a maximum ramp weight of 8,2751b.
With full IFR reserves (45min holding, two ILS approaches, alternate
II July 1981
diversion 65 n.m. plus a 10 per cent
fuel contingency allowance), a stage
length of 515 n.m. can be flown in
2hr 4min, using 1,0201b of fuel and
including a 751b allowance for taxi
and take-off. The VFR equivalent
stage would be 710 n.m. in 2hr SOmin
with 45min reserve.
This allows for a cruise climb to
FL240 (I6min for 48 n.m. using 1451b
fuel) and a cruise at 260kt TAS
(lhr 28min for 382 n.m. using 6421b
fuel at 4381b/hr), followed by a descent on track (20min for 85 n.m.
using 1581b fuel). The cruise specific
fuel consumption is 0-59 n.m./lb and
the block speed is 249ft (0-54 n.m./
lb). For this weight the take-off e.g.
range is between 155-66 and 160-04in
at 8,2001b, and without the baggage
we are a comfortable 157-52in. However, if we put the baggage weight
of 1441b in the nose compartment we
run near the forward limit with a e.g.
of 156-Olin. An even more interesting situation occurs with the baggage
in the aft compartment—a e.g. of
159-65in. At lower aircraft weights
the forward e.g. limit widens to 150-65
at 6,4781b or less.
As a guide to the operating cost,
Gatwick Air Taxis provided a quote
for a charter flight from Gatwick to
Frankfurt and return—a round trip
of some 800 n.m. in a total flying
time of 3x2hr. At an inclusive rate of
£350 per flying hour for a two-crew
operation, the total incurred is £1,225,
or approximately £1-50/n.m. — a
modest 38p per passenger mile for
four passengers. This rate is based
on a utilisation of 500 revenue hours
per annum, and the charge is down
to £325/hr for a charter over 5hr flying time. The UK agent is Northair
Aviation at Leeds, and a figure of
$1,067,500 is quoted for a very fully
equipped Corsair.
• Acknowledgements are due to the
ATC staff at Bournemouth (Hum)
Airport for their co-operation.
Q