 |
| |
| RESISTANCE - DUC FC Windspoon
blade |
| |
| CALCULATIONS AND
RESULTS OF TRIALS |
| |
| DUC FC BLADE CHARACTERISTICS: |
| PALE FC blade |
| Length of the DUC FC
blade |
835
mm |
| Weight of the DUC FC
blade (kg) |
0.735
kg |
| Position of the gravity
center - cote AB (mm) |
254
mm |
| Radius of the gravity
center (mm) |
291 mm (254 + 37) |
|
| |
| TYPE OF ENGINE : |
|
The studies were carried out on 3 types of 4 times engines
and on one type of 2 times engine.
4 times engines :
- ROTAX 912 with rotation / reducer 2.27,
- ROTAX 912S with rotation / reducer 2.48,
2 times engines :
- ROTAX 582 with rotation / reducer B 2.58,
- ROTAX 582 with rotation / reducer C 2.62,
- ROTAX 582 with rotation / reducer C 3,
- ROTAX 582 with rotation / reducer C 3.47,
- ROTAX 582 with rotation / reducer C 4.
|
| |
| CALCULATION OF THE CENTRIFUGAL
FORCE |
|
We applied the following formula :
F
= (M(kg) x V2 (m/s)) / R (m)
F : centrifugal force (N),
M : blade 's weight (Kg),
V : linear speed (m/s),
R : Radius of the center of gravity (m).
|
| |
| STATIC PULLING |
|
The static pulling with the blade in the axis uses the
same device as the offset tests with 32° (picture
1-2).
| Static pulling
with the blade in the axis : |
Delamination
at 52000 N |
|
Estimate of the static pulling with the blade in the
axis : |
Calculated break point at
90000 N * |
* It was impossible to obtain a complete rupture of the
blade because of the tears around the attaching bolts
of the system of traction.
To estimate a value of rupture in the axis, we exerted
an excentric static traction of 32° .The rupture occurred
on the level of the shoulder of blade's foot. We can consider
that the rupture of the blade in the axis represents approximately
the double of the rupture's value with 32° because
with this position, only half of the blade's foot is in
contact with the assembly.
The two tests with 32° were also carried out to observe
the behavior of the blade subjected to combined pulling.
These statements do not show to in no case reality being
given that the centrifugal force is inevitably in the
axis.
| Static pulling
with the blade with 32° of the axis : |
Break
point at 45000 N |
| Static pulling
with the blade assembled in the hub with 32° of
the axis : |
Break
point at 45000 N |
|
 |
 |
| Picture 1 |
Picture 2 |
|
|
- blade with 32°
of the axis -
|
| |
|
|
|
DUC FC BLADE- CALCULATION OF THE CENTRIFUGAL
FORCE ACCORDING TO THE ENGINE TYPE
|
|
Type of
engine
|
Max.
speed
( Tr/min )
|
Speed with
factor of
increase
1,5 (Tr/min)
|
Reducer
|
Régime
après
réduction
(Tr/min)
|
Radius
of the
gravity's
center
(mm)
|
Linear
speed
(m/s)
|
Blade's
weight
(kg)
|
Centrifugal
force
(N)
|
| 4 TIMES ENGINES |
|
ROTAX
912
|
6000
|
9000
|
2,27
|
3965
|
291
|
120,8
|
0,735
|
36832
|
|
ROTAX
912 S
|
6000
|
9000
|
2,48
|
3629
|
291
|
110,5
|
0,735
|
30859
|
| 2 TIMES ENGINES |
|
ROTAX
582
|
6800
|
10200
|
2,58
|
3953
|
291
|
120,4
|
0,735
|
36623
|
|
ROTAX
582
|
6800
|
10200
|
2,62
|
3893
|
291
|
118,6
|
0,735
|
35514
|
|
ROTAX
582
|
6800
|
10200
|
3
|
3400
|
291
|
103,6
|
0,735
|
27087
|
|
ROTAX
582
|
6800
|
10200
|
3,47
|
2939
|
291
|
89,5
|
0,735
|
20246
|
|
ROTAX
582
|
6800
|
10200
|
4
|
2550
|
291
|
77,7
|
0,735
|
15236
|
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