To demostrate how important of 4-blade design compared to 3-blade, we can calculate Tempest MKV.
engine rpm 3700 or 3850, reduction ratio=0.274, prop. rpm=1013rpm or 1055 rpm ;propeller diameter=14ft=4.24m
When dive to 6000m altitude @ 950km/h TAS=264m/s TAS=680km/h IAS=421m.p.h IAS. This speed is within Tempest MKV's permitted dive limit.
advance ratio=J=V/(d*n)=264/(4.24*1012/60)=3.7 even bigger than Fw190A8!
If Tempest was equipped with 3-blade prop, it will be badly outdived by Fw190A8, but Tempest slightly outdive P47 and P51! The reason is 4-blade prop. which provides efficiency 78%@950km/h TAS.
During the war many types of fighter aircraft were produced out of the designers bag, some never even reached the prototype stage, others failed to reach Service requirements, but not a few made the grade and are now house hold words the world over. The best known in this country are, of course, the Hurricane and Spitfire, the Typhoon, Mustang and Thunderbolt, and latterly the Tempest and Meteor. Each came out in many guises and fulfilled many roles, some of which they were never designed for, but all did a grand job of work, and were at one time or another indispensable to the work of the R.A.F. Fighter Command.
The Aeroplane June 21st 1946.
1)The best diver, Meteor, of course, not" handicapped by airscrew drag"
2)Tempest MKV(9lbs boost), the best piston diver, 4-blade prop. 5 tons, streamlined
3)Thunderbolt(P47D), the best American piston diver, 4-blade prop, 7 tons.
4) Mustang(P51B/C 18lbs boost), one of the best diver, 4-blade prop, 3.5 ton , very low drag coefficiency of laminar flow wing.
5) Fw190A8A6? Bf109G6as Spitfire IX,XIV, these a/c are outdived by P47P51Tempy. Why?
Fw190A,as heavy as P51, but not laminar flow wing, lighter than P47/Tempy. only 3-blade prop. low prop efficiency at high speed.
Bf109G6as, very good at initial dive stage, but not very heavy, 3-blade prop.
Spitfire IX, XIV, 4-blade prop. not heavy, initially outdived by 109, but can catch up with 109 due to 4-blade efficienvy at high speed, over take 109? not sure.