UPSC Mains 2013 GS Paper 3 Q17: model answer
(a) What is an FRP composite material? How are they manufactured? Discuss their applications in aviation and automobile industries. (100 words) (b) What do you understand by Run-of-river hydroelectricity project? How is it different from any other hydroelectricity project? (100 words)
What the question wants
(a) Explain FRP composites, how they are made, and their uses in aircraft and cars. (b) Explain run-of-river hydropower and how it differs from storage-based hydropower.
How to structure it
(a) What, how, where used.
- Meaning
- Manufacture
- Applications
(b) Meaning, difference.
- Definition
- Differences
- Concerns
How to think it through
(a) Fibre-reinforced polymer: fibres (glass, carbon, aramid) in a polymer matrix (epoxy, polyester). Manufacture: hand lay-up, filament winding, pultrusion, resin transfer moulding, autoclave curing of prepregs. Applications: aircraft fuselage and wings (Boeing 787 ~50% composites, Tejas), car body panels, EV battery casings. Benefits: light, strong, corrosion resistant. (b) Uses flow of river with little or no reservoir; diverts water through a tunnel to turbines and returns it downstream. Lower submergence, less displacement. Dependent on seasonal flow; little storage, so less flood control. Examples: Nathpa Jhakri, Kishanganga. IWT allows RoR on western rivers.
Model answer
(a)
An FRP (fibre-reinforced polymer) composite combines strong fibres, such as glass, carbon or aramid, with a polymer resin like epoxy. The fibres carry the load and the resin holds them in shape.
How they are made
- Hand lay-up or spray-up of fibre mats wetted with resin.
- Pre-pregs cured under heat and pressure in an autoclave.
- Filament winding for pipes and tanks, pultrusion for beams.
- Resin transfer moulding for car parts.
In aviation
- About half the structure of the Boeing 787 is composite.
- India's Tejas uses composites for much of its airframe, cutting weight and radar signature.
- Less weight means less fuel.
In automobiles
- Body panels, bumpers and EV battery casings.
- Lighter cars get better mileage; composites also resist corrosion.
Composites let engineers make things that are both lighter and stronger.
(b)
A run-of-river project uses the natural flow of a river to turn turbines, with little or no reservoir. Water is diverted through a tunnel and returned downstream.
How it differs from storage projects
- Little storage: only a small pondage, unlike the large dams of Bhakra or Tehri.
- Less submergence of land and forest, and fewer people displaced.
- Output follows the season: high in the monsoon, low in winter.
- No major flood control or irrigation benefit.
- Under the Indus Waters Treaty, India can build such projects on the western rivers, as at Kishanganga and Nathpa Jhakri on the Satluj.
Concerns
- Long dry stretches of river below the diversion.
- Fragile Himalayan slopes, as the 2021 Rishiganga flood showed.
It is cleaner, but not free of cost.
Draw: (a) A cross-section: fibres embedded in resin. (b) A sketch: river, small weir, tunnel to powerhouse, water rejoining downstream.
Keywords, cases and data to drop in
(a) FRP, carbon fibre, glass fibre, aramid, epoxy, pre-preg, autoclave, filament winding, pultrusion, Boeing 787, Tejas, EV casing. (b) run-of-river, pondage, diversion tunnel, Nathpa Jhakri, Kishanganga, Indus Waters Treaty, Rishiganga 2021.
Where most answers lose marks
- (a) Skipping the manufacturing part. (b) Saying it has no environmental impact.
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Question text as printed in the official UPSC Civil Services (Main) question paper. The model answer is original Battle IAS work; use it to learn structure, not to memorise.
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