In the encyclopedic reference book “Tanks” Hagle, published in 1935, stated that “with the installation of the dual control of the military value of the vehicles… can be enhanced as they are able to reverse it, and no u-turns”. In the early years of construction of armored vehicles were produced armored cars with two drivers occupying the front and rear control stations. An example is the armored AMD White (“white”), adopted at the armament of the French army in August, 1917, or Landsverk-185 (“the land sverk-185”), produced in Sweden in 1933 and Later, in 1951, again, the French have created even armor tank destroyer Panhard EBR75 (Panar) with 75-mm cannon, which also had dual controls.
THE FILE — CHALK
When processing a file soft metal (or plastic wood) in the notches of stuck particles of cutting material, which is not easy then to get rid of. This will not happen if you RUB the tool with chalk or charcoal.
Perhaps in the near future when the new spacecraft will go to the moon, Venus or Mars in the Arsenal of the astronauts will be robots who will come first to the planet’s surface to conduct scientific researches, to perform simple welding and Assembly work. So I decided the guys from the mug space simulation Sumy city station of young technicians and build a similar robot with their hands.
In 1933, after the purchase by the Soviet Union license on 760 HP engine “Islamo-Suiza” 12ybrs. N. N Polikarpov again returned to the idea of creating a fighter with a liquid-cooled engine. The planned armament of two synchronised ShKAS machine guns and two promising guns ShVAK (nonsynchronous) caliber 20 mm. To achieve high speed, the fuselage is compressed to the limit, causing the cockpit was very cramped. Flight tests of the first instance And-17 began in the fall of 1934, but due to the identified deficiencies was short-lived. 
The weak point of any piston pump — automobile, motorcycle or Bicycle, as is well known, piston, or rather, leather cuff, and the main fault is a loose fit it to the cylinder walls. The fact that the skin shrinks, warps, cracks.