The MOUNTAIN GOAT STOL is the result of
seven years of development, addressing the particular needs of
Alaska bush pilots. Two years were spent researching the
requirements and disposition of bush pilots, including perceived
shortcomings of the existing bush plane fleet; useful load
requirements; undesirable flight qualities of the existing bush
plane fleet; undesirable structural qualities of the existing bush
plane fleet; determination of the real world performance of the
existing bush plane fleet; what happens in typical crashes; FAA
regulations related to certification processes; design criteria
needing to exceed the requirements of FAA regulations; and
available, state of the art technologies capable of benefiting
design goals predicated by the research.
Some things we didn't learn until
after we built our first prototype. We found for instance that in
some cases, field repair capability is considered preferable to
advantages measured purely in terms of performance. Over a period
of several more years, each issue raised by the bush pilot
community was addressed. A composite wing was eliminated over
concerns of "in field" serviceability. A new technology for an all
metal wing was developed which provides the cost benefits of a
metal wing while achieving the aerodynamic benefits of a composite
wing. Engine power output was increased to 180 horsepower factory
specs, with additional performance derived from exhaust and
propeller refinements. We developed an exceedingly quiet,
high-performance exhaust. Additional aerodynamic modifications
were made to achieve better performance. One of the greater
challenges was to design an empennage providing the performance
required for FAA certification standards, while providing equally
outstanding performance at 180 mph IAS and above.
The MOUNTAIN GOAT STOL™ uses as
standard equipment, a McCauley 76-inch diameter, 66-inch pitch,
fixed pitch prop. We regularly operate out of short, rough strips
at any altitude, taking off and landing in the same distance as a
good, lightly loaded Super Cub™ with an 82 inch prop with 40
inches of pitch — a rig which substantially benefits the Super
Cub™ to achieve speed and climb.
As soon as we are off the ground, we are
climbing at over 1,000 ft per minute — at a faster speed than the
Super Cub™ will fly at full throttle and level. If the Super Cub™
is in stable, maximum rate of climb, full power, with the 82 / 40
prop, and the MOUNTAIN GOAT STOL™ has the same load and full
throttle, the Super Cub™ will be climbing at about 1,200 ft/min,
at about 63 mph at 3,000 ft. The MOUNTAIN GOAT STOL™ will be
climbing at 2,200 ft/min, at 110 mph.
The MOUNTAIN GOAT STOL™ can take off in short
distances because the wing has more than twice the lift of a Super
Cub™, and less than half the drag. The wing uses a state of the
art airfoil developed from aerospace research by Bill Montagne,
implemented in a flush riveted wing, flaps, and flaperons. The
accurate structure of this wing, and its state of the art
mechanical and aerodynamic technology, distinguish MOUNTAIN GOAT
STOL™ performance above what are really antiquated designs, far
behind the curve of modern developments. We don’t use an 82 /40
prop, because we can achieve substantially superior performance
without the diameter and pitch, and without the inherent landing
clearance risks.
specifications
powerplant
propeller
length
height
wing span
wing area
seats
empty weight
useful load
gross weight
fuel capacity
range |
Lycoming IO 360 B2E, 180 HP, 2000 hr TBO
McCauley fixed pitch 76-66
24.3 ft
6.75 ft
35.5 ft
188 sq ft
2
1250 lbs 4130 Chrome Moly alloy airframe; 1170 lbs Titanium
airframe
1250 lbs 4130 Chrome Moly alloy airframe; 1330 lbs Titanium
airframe
2500 lbs
65 US gallons
1,400 statute miles |
performance
(Mountain Goat STOL
with 26ins dia × 10.5 × 6
Goodyear Tundra tyres)
takeoff distance,
ground roll
rate of climb
max speed
cruise speed
landing distance, ground roll
service ceiling |
300 ft
1,200 fpm
x
159 mph
275 ft
x |
limiting and recommended speeds
design manoeuvring speed (Va)
never exceed speed (Vne)
stall, power off (Vsl)
landing approach speed |
120 mph
x
50 mph
x |
All specifications are based on manufacturer's
calculations
|