Originally Posted by
pilotmike
I agree - the numbers simply don't add up.
The actual figures, with 1 lifting balloon capable of lifting 20kg every 250m, to a height of 1000m are (in grammes):
mass of netting per sq m = 20,000g / 1000m / 250m = 0.08g per sq m.
For comparison;
3/4 ounce ripstop nylon, commonly used for light weather spinnakers, kites and tents, is 42 grams/square metre.
Paper is often quoted in GSM (grams per square metre), with values around 90GSM for typical office printer paper.
Converting from a description of 17 Inch x 1500 Feet 40 Gauge Pre Stretch Plastic Wrap Pallet Wrapping 4.75 Lbs per Roll (heavier than kitchen wrap) I get about 10grams per square metre.
OK perhaps we can build a net from monofilament (fishing line)?
I'm finding a 100m reel of 10lb (4.5kg) monofilament weighs about 50 grams, thus about 0.5g per linear metre.
If we make a mesh out of it, with a square pattern, each square metre of mesh has 2 metres of line / (mesh separation in metres).
eg: 1 square metre of 1m mesh has 2 metres of line, 1GSM.
To achieve 0.1GSM requires mesh with 10m openings...
0.08GSM = 12m x 12m openings in the mesh.
You could fly a Cessna 172 with a wingspan of 11m through it on a good day...
Originally Posted by
pilotmike
That would be an incredible material! If it could stop a mosquito, or even support its own weight it would be nothing short of a miracle. ... It must definitely be made from that magical, mythical new Engineering material, recently invented by the Russians, known as Unobtainium.
Or use it to build Arthur C Clarke's
skyhook to orbit.
Originally Posted by
pilotmike
It is extraordinary that the propaganda machine of Russia continues to spout such utter garbage, hoping it will be believed. This proposed defence device is supported purely by a load of hot air!
Realistically, what fraction of Russia's population has the ability AND the inclination to look at a claim like this and do some numbers to pronounce it nonsense by several orders of magnitude. As a slightly obsessive engineer (see above...) I do it all the time, but very very few other people do unless they're actually interested.