Originally Posted by
Cedrik
I made the post I did on page 1 of this thread because I was flying fires the day before in Vic, the conditions were very rough. That's why I bought up the topic of structural failure.
My only experience of fires is as a glider pilot before our farmers were banned from burning crop stubble in the fields.
A good one, if they lit the field on all edges instead of just downwind, so it accelerated by sucking in air from all round, could be going up at well over 10 knots if you could fit a decent turn right in the middle. I saw one in Bedfordshire or Cambridgeshire which really went. They lit the field next to the one I was circling over, it came up like an arm with clenched fist, and in about a minute and a half or two there was a new cumulus to well over the 5000' base, maybe 7000'. I was afraid to go in it, assuming that a 30 knot or so vertical gust might cause some damage, to aircraft or me, or at best very little chance of controlling the glider well.
But that is tiny compared to the energy going into the Australian fires. I'm assuming the cores of strongest lift in some of these forest fires can be a lot stronger and rougher. Can you see well enough to slightly avoid the strongest and most opaque bits, come back when that's died down a bit, or are you trying to deliberately hit them at the worst moment?
I watched some aircraft bombing a fire in the south of France a couple of years ago, but this was actually a fairly modest size. Of course the attempted photos are little more than a speck from a kilometre or so away.