Contrails
 

G'day

Can someone please tell me why you would see more contrails produced by aircraft over flying Canberra than you would see in Perth, even though they are most likely at a similar height. (Obviously contrails rely on relative humidity which I wouldn't have thought would be higher over Canberra than Perth). I'm not sure if this makes any difference that Canberra is roughly 1800+ft above sea level and inland, compared to Perth that is only approximately 100+ft above sea level and close to the coast.

Much more simple than you would think :)

Canberra is a point that is overflown by aircraft flying between Sydney, Melbourne, Brisbane and Adelaide. Whereas not many aircraft will overfly Perth at altitude while going to other locations.

To relieve my confusion, are you trying to say that there are less "Contrails" over Perth, due to there being a lessor number of aircraft over-flying that point?

If so, I would agree with your answer. Otherwise, I'm really confused!:confused:

I presume that what the original poster was alluding to was not number-of-aircraft based but rather the aircraft that do overfly such places, theres a higher probability of contrails at one over the other.

Contrail causation
 

Maybe slightly off topic, or maybe not..........

Does anybody know how often turboprops can/do cause contrails?

Logic tells me that they wouldn't be any different to any other kero burner, but I don't really recall seeing/hearing about such until recently. Whilst I didn't actually sight the aircraft, a set contrails passed under me the other day and the only aircraft I had heard in the area was a B200.

Any ideas........

Perhaps this Contrail Java applet will help - you can play with the various aspects of the aircraft you are considering in order to see whether the contrail form or not.

S'obvious. Them thar folks in Canberra need more sprayin' than them ones in Perth. :E

During WWII Contrails were indeed produced by B-17s etc. at cruise altitude and represented a threat to their bombing ops - they made it much easier for spotting by interceptors. In many wartime photos you can see them produced by the props disturbing supersaturated air.

The Dash 8 Q400 'trails' in the right conditions; seen it for real, but not in photographs.

Watched a C172 do a go around at Merrill Field, Alaska last week. It was humid and around -5C. As he pulled up, the airplane started to make two strong contrails from the edge of the flaps that remained in place for 5 minutes or longer, from the point of the go around almost to the downwind. Looked real cool.
So you don't need to be high or fly a big airplane...