thoughts on life at Stanford and beyond

 

how the Wright brothers invented the airplane

25 Sep 2011




As author Lester Garber has noted, there were a number of key breakthroughs the brothers had to make:

  • recognizing that problems of stability and control must be solved before attacking problem of powered flight;
  • recognizing that given adequate aircraft, pilot must still learn how to fly;
  • recognizing that to maintain equilibrium, control is more important than inherent stability;
  • recognizing that use of aerodynamic forces superior to weight-shifting for maintaining control;
  • using of wing warping to vary angles of attack from tip to tip for roll control;
  • recognizing that aeroplane must bank its wings in order to turn;
  • doing wind tunnel tests to determine lift/drag characteristics of different wings;
  • realizing that the real value of Smeaton’s coefficient is really .0033;
  • recognizing of the need for 3 dimensional control;
  • understanding that the proper function of the vertical rear rudder is yaw control, not turning aeroplane;
  • the development of a method to design efficient propellers;
  • the development of a lightweight engine with sufficient horsepower.

The only real account from the brothers themselves, however, is in an old Harper’s magazine article, which I’ve scanned and posted below (I believe it’s out of copyright):

 
 

a look at the new Mars Rover

25 Sep 2011

I got a glimpse of the new Mars rover, Curiosity, in the clean room while taking a tour of the JPL a few months ago. Unlike the last Mars rover, which landed with the aid of a parachute and air bags, this one is going to be lowered down on a cable from another stage which hovers above. It’ll be powered by radioisotope thermoelectric generators (RTGs) instead of solar panels, so dust getting on the rover shouldn’t be an issue. It’s got a pretty neat and tiny X-ray diffraction instrument on board – if you’ve ever been to a university lab that has one, you’ll know that they’re normally the size of an entire bench. I thought initially that inXitu had used the field emission from carbon nanotubes to produce the X-rays, but it seems like it uses a miniature X-ray tube that consumes just 10 Watts of power.