47
2
The National Aeronautical Laboratory (NAL, which is an outfit
of the Council of Scientific and Industrial Research in India) has
developed a CFRP wing using a carbon/epoxy prepreg for 14-seater
civil aircraft called Saras. The entire bottom substructure (having
dimensions of 5.1 m × 1 m that consist of a skin, 2 spars, 11 ribs, and
8 stringers) has been co-cured in one single operation. The processes used were vacuum bagging and autoclaving.
2.3.3 Stealth Aircrafts and Frigates
Composites play a key role in stealth aircraft and frigates. The B-2
stealth bomber of the US Air Force and the stealth frigate of Sweden
(shown in . Fig. 2.19) are nearly invisible to radar and are both
made out of composites. The B-2 bomber is made out of carbonreinforced composites, and the matrices used are primarily epoxy
and polyimide resins. This composite is able to absorb all radar frequencies, making it completely invisible. In the case of the stealth
frigate, it not only absorbs all radar frequencies but also does not
leave any magnetic footprint due to the nonmagnetic character of
composites. Therefore, it becomes undetectable by enemy radars.
Camouflaging paints are applied on its exterior surface to make it
visually undetectable too.
. Fig. 2.18 The Robo-Raven micro air vehicle (MAV) [36]
a
b
. Fig. 2.19 a B-2 stealth bomber and b Visby class stealth frigate made out of composites [37, 38]
2.3 · Applications of Polymeric Composites
2
The National Aeronautical Laboratory (NAL, which is an outfit
of the Council of Scientific and Industrial Research in India) has
developed a CFRP wing using a carbon/epoxy prepreg for 14-seater
civil aircraft called Saras. The entire bottom substructure (having
dimensions of 5.1 m × 1 m that consist of a skin, 2 spars, 11 ribs, and
8 stringers) has been co-cured in one single operation. The processes used were vacuum bagging and autoclaving.
2.3.3 Stealth Aircrafts and Frigates
Composites play a key role in stealth aircraft and frigates. The B-2
stealth bomber of the US Air Force and the stealth frigate of Sweden
(shown in . Fig. 2.19) are nearly invisible to radar and are both
made out of composites. The B-2 bomber is made out of carbonreinforced composites, and the matrices used are primarily epoxy
and polyimide resins. This composite is able to absorb all radar frequencies, making it completely invisible. In the case of the stealth
frigate, it not only absorbs all radar frequencies but also does not
leave any magnetic footprint due to the nonmagnetic character of
composites. Therefore, it becomes undetectable by enemy radars.
Camouflaging paints are applied on its exterior surface to make it
visually undetectable too.
. Fig. 2.18 The Robo-Raven micro air vehicle (MAV) [36]
a
b
. Fig. 2.19 a B-2 stealth bomber and b Visby class stealth frigate made out of composites [37, 38]
2.3 · Applications of Polymeric Composites