MagicManICT wrote:Vassteel wrote:shubla wrote:I think that hitting swans by knarr should rip the sail of it.
Then you would have to repair the boat with cloth.
Please explain how a 20 pound bird would damage a knarr. I really would like to know.
How does it damage a 20 ton aircraft? Yet planes crash after hitting birds. (Granted, bird strikes to engines are the specific problems. Despite engineering for it, engines are still vulnerable.)
You are flying along at a few hundred mph and you hit a stationary (from your point of view) few kg of bird, the bird is going to accelerate faily quickly which is going to involve a certain amount of force being transferred to your plane. That isn't normally serious unless it hits somethign delicate like a radar dome or flap. Or it goes into an engine! Turbine blades are in a very stressful situation, they don't have a lot of spare strength to resist accelerating a bird to 200mph. When they break off they tend to go backward into the rest of the compressor
Eg 0.5kg bird hitting a plane doing 200knots e = 1/2 * 0.5 * 100^2 = 2500 J Worst case would be a fighter at mach2 hitting a Canada goose, E = 4,500,000 J Comparison, a typical handgun bullet is around 500 J ( although concentrated in a smaller area)
some more technical math on bird strikes
https://www.tc.gc.ca/eng/civilaviation/ ... -1-410.htm