A plane towing a line of digits that stretches across the sky, the numerals starting large, but gradually diminishing in size until they are invisible to the naked eye.-- xenzag, Mar 14 2015 Pi day http://www.theguard...man-who-invented-pi [xenzag, Mar 14 2015] Ofcourse with this you only need a banner half as long http://www.tauday.com/ [zeno, Mar 14 2015] Vi Hart: NOT Pi day https://www.youtube...watch?v=jG7vhMMXagQ [pashute, Mar 15 2015] A fine idea, but I think it's going to have to be an airship or a helicopter. A banner that stretches "across the sky" is going to be anywhere between a few miles and a few tens of miles long (depending on the altitude its flying at). I'm not sure how much drag is caused by a 5-mile long, several-metres-wide ribbon at the speed of a light aircraft, but I imagine it is not insignificant.
In fact, there must be a limit to the length of banner that can be towed. At some length, the drag on the banner (if it's moving fast enough to remain mostly horizontal) will be greater than the banner's strength. Make the banner of stronger stuff, and it'll be heavier, which means you'll have to fly faster to keep it straight, which means more drag...-- MaxwellBuchanan, Mar 14 2015 OK - a quick Google shows that the largest banner ever flown was 50,000 square feet. It was flag- shaped, but it suggests that a 10ft wide ribbon couldn't be longer than 5000ft. And this large banner was flown by a helicopter.
The largest banner flown by a plane was only 2300 square feet (so, a 230ft x 10ft ribbon).-- MaxwellBuchanan, Mar 14 2015 A speed of light aircraft will probably produce infinite drag, no matter how long its banner.-- pocmloc, Mar 14 2015 //the speed of _a_ light aircraft//-- MaxwellBuchanan, Mar 14 2015 Pedant.-- pocmloc, Mar 14 2015 When I'm sober enough to stand up, I'm a bipedant.-- MaxwellBuchanan, Mar 14 2015 Not a banner.... Line of digits.... Pay attention!-- xenzag, Mar 14 2015 Ah yes.
So, are these abstract digits? Or are they embodied in some tangible form? Or are they, perhaps, fingers?-- MaxwellBuchanan, Mar 14 2015 I imagined outline digits composed of very fine but strong material like carbon fibre. They would be connected to each other with something like cat-gut and diminish in size as they progress down to about 12 point type. Ah the tiresome details......-- xenzag, Mar 15 2015 Pie day is my wife's birthday. Its also Vi Heart's fascination.-- pashute, Mar 15 2015 I wonder what a topflight fighter could pull if the banner was a suitable material?-- wjt, Mar 15 2015 I wonder what a topflight fighter could pull if the banner was a suitably light combustible material?-- zeno, Mar 16 2015 Some fighter jets have chute anchor points so all that is needed is a cable to withstand thrust exhaust and probably some flight ballast to orientate the banner.
Bring on the fighter jet ribbon gymnastic display.-- wjt, Mar 19 2015 //fighter jet ribbon gymnastic display.// Now, there's an idea...-- MaxwellBuchanan, Mar 19 2015 why? [+]-- Voice, Mar 19 2015 They could be numeral-shaped balloons. Get the density right and their weight wouldn't be an issue. Provided you fly into the wind, it doesn't matter how fast you go - the line should stay straight, right?
//why?//
Presumably, Pi day celebrations.-- Loris, Mar 19 2015 random, halfbakery