Caravan-On-Steroids Sports 900 SHP And A Texas Performance
Attitude To Match
It is hard to believe the Cessna Caravan first rolled off the
assembly line 25 years ago. By 2005, the total operating fleet
worldwide had mushroomed to some 1,500 aircraft, amassed more than
8 million flight hours at a rate of more than 71,000 hours per
month, and FedEx claimed to be operating its aircraft at a 99%
dispatch rate.
The Caravan has certainly earned the right to call itself one of
the most successful general aviation designs, but as well all know,
aircraft ownership comes with a price. To make money you have to
spend money, and the Caravan is no exception to the rule. With a
3,600 hour TBO, the Pratt and Whitney powerplant eventually needs
to be overhauled or replaced. Depending on the condition of the
engine, an overhaul can cost anywhere from $200,000 to $300,000
minus the core credit. If you want to go new, the replacement can
set you back a cool $400,000.
There is another aspect of the Caravan that also comes to play
in deciding what to do with the engine. 675 shp is no slouch for a
single-engine aircraft, but many Caravan operators fly this
aircraft in what can only be described as challenging conditions.
After all, the aircraft was originally designed as a bush aircraft.
In high density altitude and high temperature conditions, or in
distance-challenged takeoffs, the aircraft can leave operators
wishing they had an option for that little extra "oomph" that might
make the difference between a successful takeoff and lopping off
the tops of trees in the Amazon jungle.
Over the years a number of suppliers have come up with upgrades
to improve the aircraft's performance. Blackhawk Modifications
recently announced their PT6A-42A upgrade to 850 shp, and AOG Air
Support offers its AOG Hot Wings wing design modification.
Texas Turbine Conversions decided to enter the fray and design a
completely new firewall-forward package, but they chose to use the
Honeywell TPE-331-12JR engine and a Hartzell 110" four-blade
propeller, as well as a some panel, electrical and other minor
modifications.
Aero-News interviewed Texas Turbine Conversions' Bobby and Kim
Bishop, the husband and wife team behind the company, to get the
details of this program and the value proposition they offer to
their customers.
Since the company does not overhaul engines, its upgrade is only
for new TPE-331 engines. The -12JR is rated at 1,100 shp but for
this installation they are derated to 900 shp. The conversion
package is priced at $645,000, not counting core credit. Because
PT6A-114 and -114A cores are in high demand, they can fetch between
$100,000 and $400,000 depending on condition.
For the purposes of this analysis, we assume a run-out engine at
the bottom of the range. That said, simple arithmetic brings the
net cost of the package (not counting down time, ferry, etc.) to
roughly $545,000.
The result of testing has revealed that you not only get more
power out of the conversion, you get a fuel consumption savings at
cruise power settings of about three to four gallons per hour. If
we compare TBO to TBO, that means that over what should be the
useful life of a PT-6A-114 with a 3,600 hour TBO, the operator
should save around 10,800 to 14,400 gallons of fuel.
To place a valuation on that, Aero-News chose the price of Jet-A
at KINK (Wink, Texas), a popular fuel stopover for east- and
west-bound aircraft, currently $3.72 per gallon, resulting in
savings of $40,176 to $53,868. This is a simplistic calculation,
but you get the idea. Spot prices for jet fuel peaked in June 2008
at more than three times current pricing, and if it happened
before, it can happen again.
However, TBO comparisons don't stop there. The TPE-331-12JR has
a TBO of 7,000 for commercial operators and 5,000 hours for
non-commercial operators. That represents almost 100% additional
useful life for the engine for commercial shops, and therefore 100%
more time to make money with the equipment before you have to lay
out another chunk of cash and four weeks of down time.
To the pilot, performance is the bottom line, and here the Texas
Turbine Conversions package truly excels. Noise levels are higher
on the ground because of the well-known high pitched noise of the
Honeywell engine, but noise levels in climb, cruise and descent are
reduced some three decibels because the prop operates at a slower
1,591 rpm. Cabin noise is also lower, for the same reason. Basic
takeoff performance is reduced from 1,405 feet to 1,054 feet, and
distance to clear a fifty foot obstacle is reduced by an impressive
25% to 30%, from 2,420 feet to 1,875 feet. The conversion improves
climb performance by over 60% at lower altitudes and over 100% at
10,000 feet. According to the company, it takes just under thirteen
minutes to climb to 14,000 feet MSL on a 35°C/95°F day at a
takeoff weight of 9,000 pounds. Climb performance at gross weight
and ISA increases from 975 to 1,510 feet/minute. Cruise speed at
equivalent flow settings improve by as much as 15 knots.
What this all translates to, according to customers who are
operating the aircraft, is faster turnarounds, along with a 312
pound increase in gross weight, 100 pounds of those coming from the
engine conversion and the rest tacked on to useful load. The lower
fuel consumption translates to longer endurance and a max range of
1,000 nautical miles as opposed to 915 for the stock Caravan.
All in all, this has all the signs of a very profitable value
and performance proposition for operators who can use this kind of
performance, and that translates to a direct positive impact on the
bottom line. So far the company has received certification for the
208B on wheels. They are finishing the testing on the 208
amphibious and wheels Caravans, and expect to receive the paperwork
from the FAA in the first quarter of this year.
Certification for the 208B on floats is expected in the fourth
quarter of 2009.