Guppy tends to run on-and-on-and-on...and never truly answers the question.
Having flown large 4-engine piston airliners extensively, induction air icing has never been a particular problem (period) on both Douglas and Lockheed (and even twin engine Convair 440) designs...DC4, DC6, DC7, L1649...specifically.
Not saying it can't happen, just that I have never experienced same.
Cessna 401/402/411/421 types?
No, not those either....and I personally own one of the above.
Next question?
