Question: Which Formula One car besides the Tyrrell P34 was one of the most radical entries ever to succeed in F1 competition, that used flat panel heat exchangers? 
Sentence (from "Tyrrell P34"): The Tyrrell P34 (Project 34), commonly known as the "six-wheeler", was a Formula One (F1) race car designed by Derek Gardner, Tyrrell's chief designer.
Relevant evidence: Yes