Four Bladed Props

[NARSES2]

Thanks Jon that's cleared that up. As I say it's just something that niggled at me before

[KJ_Lesnick]

rickshaw

Yes.

Variable pitch correct

[wuzak]

Well, the P-51 got 4 bladed props when it went from V-1710 to V-1650 power.

The Spitfire went to 4 blades when it took the Merlin 61. Also the high altitude Mk VI (100 built) used a 4 bladed prop. The Spitfire XII (100 built) also used a 4 blade prop. The XIV and later Spitfires used a 5 blade prop.

Typhoon adopted 4 blade prop from early 1944. Tempest from the start?

Mosquito used 4 blade props on the Sea Mosquito (like the Typhoon, for improved take-off performance) and the high altitude NF.XV. The rest stayed with 3 blades even when hey changed to Merlin 60-series engines.

The P-39 and P-40 stayed, I believe, with 3 blades for their service life. The XP-40Q did have a 4 bladed prop, and the P-63 did also.

F6F seemed to use 3 blade props throughout, the Corsair getting the 4 blades for the F4U-4 very late in WW2.

The P-47 looks to have had the 4 bladed prop right from the start.

So, while it seems that the 4 bladed prop was used when power was increased, some of the Allies' most powerful fighters made do wih 3 blade props. But that may have been due to prop diameter limitations, in aircraft such as the Spitfire. The F4U, on the other hand, was specifically designed to swing a very large prop, hence the inverted gull wing.

[wuzak]

The Germans, on the other hand, mostly stuck with 3 blade props.

[KJ_Lesnick]

Also the high altitude Mk VI (100 built) used a 4 bladed prop.

First flew: December, 1941

Tempest from the start?

Yup

The P-47 looks to have had the 4 bladed prop right from the start.

The XP-47B did actually -- I checked:  First flight was May 6, 1941.

The F4U, on the other hand, was specifically designed to swing a very large prop, hence the inverted gull wing.

Yup

the Corsair getting the 4 blades for the F4U-4 very late in WW2.

The F4U-4 in addition to having a more powerful R-2800 had an intercooler as well: The climb-rate of the F4U-1 was very good, but the F4U-4 was superb. 

I'm curious if the F4U-1 could have been fitted with any of the following

• Twin-stage twin-speed supercharger (which I think it already had) with intercooler to increase critical altitude
  
• Four bladed propeller
  

From the outset or by the F4U-1A series

[wuzak]

The F4U-1 had both a wo stage supercharger and an intercooler.

The F4U-1 had the R2800-8 which was, without checking my books, a B-series R-2800. The R2800-18W in the F4U-4 was a C-series, which was, in many respects, redesigned compared to the B-series.

The R-2800-8 isn't going to get more power without getting the improvements in the C-series.

The R-2800-10 used in the F6F was exactly the same as the R-2800-8 except it had a downdraught instead of updraught carburettor.

[KJ_Lesnick]

The F4U-1 had both a wo stage supercharger and an intercooler.

Cool...

The R-2800-10 used in the F6F was exactly the same as the R-2800-8 except it had a downdraught instead of updraught carburettor.

Aren't downdraft designs even more prone to flood?

[wuzak]

Don't think so. It's just the way the intake points.