Wednesday, March 26, 2008

Reverse Gear (Banter)

Well the title says it to some extent..... Not serious stuff in this

The idea came when I was sitting in one of the flights in Tucson Airport leaving for an onsite interview.

The announcement : "AAhhhh...we are waiting for the TUG to push us back ..once that happens we are clear for departure ..."

For the impatient guy I was I could not wait and I thought why does not a plane have a reverse gear?
(My friend who was overlooking my shoulder said "coz the pilot does not have a rear view mirror :D")
Now I told you I am going to an interview and the book in my hand was Programming interviews exposed which means I would attack this problem "STEP BY STEP " mwhahahahhah

First when I mean reverse gear do i mean the reverse gear while taxiing on the land or while flying?

On Land :Well the only reverse we see in a plane is when it is on land. So to understand why there is no reverse gear we first need to know how it goes forward.
After some discussions with my mechie roommates and reading, I figured out that an aeroplane's tires are not rotated by an axel(or drive shaft to be terminologically correct) powered by an engine(like in a car). Instead the wheels are just like hotwheels :D and the plane moves forward coz of the thrust generated by the jet engines(even on the ground yes). So to go back the plane would need a mechanism to turn the engines in the reverse or to generate thrust in the reverse direction. This would cost (probably) much more than the purpose it serves. So instead the job is done by a TUG.

While Flying: Now to do a reverse the vehicle needs to come to a complete stop and then take a reverse. If a plane is stopped in flight i dunno about reverse but it is going to fall for sure. And instead of investing in a mechanism to keep it from falling when it stops mid-air and then a mechanism for reverse, it is cheaper to take a U-turn which areoplanes do.

Now all these might be worth the investment if we were in JETSONS age wherein there are traffic signals and lots of congestion even in air/space. Till then impatient people like me have no option but to wait for the TUG to push back. :)