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The fuel-injected Silent 2 sets the standard
in light
self-launching sailplanes. The carbon-fiber wings of the Silent
2 have been designed to meet demanding performance objectives:
they have an elliptical lift distribution, large removable
winglets, and an increased wingspan of 13 meters.
The wing geometry is unique in that it varies non-linearly
from the root to the tip, both in overall planform shape and
in wing section profile. Creation of these unique wings was
possible due to the use of advanced materials technology,
new computer simulation methods for the
wing structural and aeroelastic analyses, and the availability
of a large multi-axis CNC milling machine
for production of molds accurately replicating the complex
computer generated surface.
The oven-cured wing structure includes extensive use of carbon-fiber. The sandwich skins use vacuum-bagged carbon fabric for the interior layer and glass fabric for the exterior layer while the tapered I-beam wing spar uses pultruded carbon rods for the constant-width spar caps. Ultimate load tests were successfully performed in a 54°C (129°F) heated booth, verifying that the wings meet JAR guidelines. Even with the increased span, the wings are significantly lighter than the 12m fiberglass wings of the Silent Club, keeping the inertia low and the roll rate high (not to overlook even easier handling during assembly).
The flight performance characteristics are the primary criteria that distinguish the Silent 2 from the already well known Silent Club. Flight tests of the 13m carbon fiber wings show that they have exceeded expectations. Tests confirm shorter take-off distance, increased power-on climb rate, attached airflow at low speeds (visualized via tuft testing), excellent stability in thermals, very smooth ride in turbulence, a stall speed below 65 km/h with landing flaps, and a maximum efficiency of at least 39 (an improvement of 8 points with respect to the Silent Club).
| Silent
2 Brochure |
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| Performance |
| Stall
speed (VS): |
<
65 km/h |
| Maneuvering
speed (VA): |
150
km/h |
| Maximum
speed (VNE):
|
220
km/h |
| Max.
L/D: |
39 at 90 km/h |
| Minimum
sink rate: |
0.60
m/s at 85 km/h |
| Take-off
distance: |
140
m (on asphalt)
170 m (on grass) |
| Landing
distance: |
100
m |
| Climb
rate with engine: |
2.5
m/s |
| |
Technical Data |
| Wing
span: |
13
m |
| Length: |
6.35
m |
| Height: |
1.25
m |
| Aspect
ratio: |
19.2 |
| Wing
area: |
8.8
m2 |
| Planform: |
Elliptical |
| Profile: |
IMD
050 (16%) |
| Empty
weight: |
175
kg |
| Max
payload: |
105
kg |
| Max
weight: |
300
kg |
| Wing
load factors: |
+5.3 g / -2.65 g
(at 150 km/h at 300 kg)
+4.0 g / -1.5 g
(at 220 km/h at 300 kg) |
| Wing
loading: |
34
kg/m2
|
| Flaperons: |
L
+1° 0° -1° S |
| Air
brakes: |
Conventional
|
| Fuel
capacity: |
17
lt (reserve 4 lt) |
| Fuel
consumption: |
5
liters/h at 75% power |
| Engine:
"Alisport A302efi" 28 hp single-cylinder air-cooled
engine, with counterbalance shaft, tuned exhaust, computer
controlled mapped fuel-injection and electronic ignition
system, electric starter and flywheel generator. Engine
extension and retraction operated by electromechanical
actuator system. Patented counter-balanced teetering mono-blade
propeller. |
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to Silent 2 home page
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