Thanks evansb and con-pilot,
I’m sure you are right. Don’t know when the pneumatic boot was invented. Perhaps it was relatively new circa-1935? Flying a civil transport IFR with no ice protection in North America or Europe in winter sounds a hairy, but I don’t remember seeing them ever in Africa.
Hi pigboat,
Have been there, on the C47. Is that Gann, by any chance? It's about 35 years since I returned Fate is the Hunter to the library, but I remember him saying that the DC3 was a revelation after the DC2 and other contemporary transports, i.e., handled much better in icing. I've only 500 hrs (P2) on Daks, in the late 'Sixties, and they had to have boots on all leading edges in the UK by then.
I guess you would tell me that the trick with boots is to pick the right moment, or you've blown it. We had levelled off the almost-empty freighter at FL80 in the tops of strato-cu. My leg. The skipper was 64, a great guy who had thousands of hours on DC3s and C47s. I proposed climbing to 100 but, by the time it became evident it would have been a good idea, the IAS had dropped from 120kts to below 100.
We used the boots as usual but, apart from a few bits that became jagged, the ice seemed to be pretty unaffected. We had no choice but to descend, as climb power was not enough to stabilize the IAS. We used the prop deicing now and again, getting a lot of noise as the bits hit the fuselage. Further cycles of the boots made no difference. The windshields rapidly iced up. There was no point in using the limited alcohol to deice them, as we had about 90 mins to destination; so they were soon completely opaque. Unfortunately, the freezing level was about 3000ft, and the bottom of the cloud was about 2000. Just as well we were over the low countries and the North Sea, because that was the altitude at which we were able eventually to level off. When a patch of clear glass appeared on the windshields, we could see a horn of ice sticking forward about six inches from the frame between the two. The ice started to un-stick from the boots.
After about another half an hour, we landed at Gatwick. On arrival at the ramp, there was still a significant amount of glaze ice on the bottom of the fuselage just behind the nose. I’ve since speculated on how we’d have got on if we’d had a 3-tonne load; like the previous leg. No doubt the Dak is fairly typical of its era: most of us are spoiled nowadays. But it seemed to handle okay. What’s the PBY like in icing?