ASTB Q's

[Daedalus]

Have a few Q's concerning the guides on this site. The Aviation and Nautical info section:
# 51 which launch vehicle is not in the US program, it lists e as the answer, delta. Delta is made by Boeing and has been used for decades. All of the choices listed have been used by the US, NASA.

#52, Why does pilot dump fuel prior to emergency landing. The answer is listed as to increase maneuverability, not for fire prevention. I would think that less fuel take mass away from the plane system, but would not aid a huge amount in the maneuverability. I would think fire prevention to be the reason. Then again the less fuel in the tank, the more aerosol fuel there would be present making it more likely to catch a spark, but then a plane can have an emergency landing at any pre landing fuel capacity.


#55 I would think dry air would be lighter than humid air, yet the answer is listed as humid, can anyone explain?

 

[contradickshon]

Daedalus,

The primary benefits in dumping fuel in order to make an emergency landing are: (1) decrease the sink rate (2) decrease the landing roll distance. Dumping fuel in a Cessna 152 flying at 3000 ft. has negligible effects compared to a jet airliner carrying 70,000 kilograms of kerosene flying at 30,000 feet.

As far as the dry/humid air question goes, humid air is 'ligher' than dry air becuase the atomic weight of the water molecules that occupy a specific volume of atmosphere are lighter (18) than the nitrogen (28) and oxygen (32) molecules that they displace. Seems counter-intuitive but true.

hope this helps

 

[Penguin]

I barely remeber the launch vehicle question, it's been a long time since I studied for that bad boy. It seems to me that the trick was which vehicle had not been used in the manned space program. Is that how the question was worded? Just a SWAG...

 

[zulu240]

i missed those also daedalus