PB2Ys

[Jack Cook]

Tanapang Harbor, Saipan 1945

Why do engines #1 & #4 have 3 bladed props??

[skymstr02]

The two inboard props were Curtiss Electric reversable to make docking and beaching easier since there are no brakes while water taxiing. The outboard props were standard feathering props.

[The Inspector]

That must have required some planning ahead for the crew as the Ham-Stans were oil and reacted very quickly, and the Curtiss' were noticably slower and 'increase' and 'decrease' pitch meant exactly the opposite thing between the two.

[Jack Cook]

you'd think they'd be more effective on the outboard motors.
That must have increased their maintenence requirements with
different props and dash number motors.

[b29flteng]

The four bladed props may because of unwanted airframe harmonics?

[The Inspector]

I wonder just how much fun the Engineer had syncing up two completely different types and styles of propellers and how busy he must have been during climbs or descent
Sort of like a Machiavellian organ player?

[jdvoss]

IIRC, I once read where the in-board 4 bladed props were added onto "Flag Transports" as a means of noise reduction. Adm. Chester Nimitz (among other ranking personnel) used PB2Y's as their assigned personal transports.(e.g. PB2Y-3R & -5R).

[the330thbg]

I wonder just how much fun the Engineer had syncing up two completely different types and styles of propellers and how busy he must have been during climbs or descent
Sort of like a Machiavellian organ player?

LMAO

Like the wizard in wizard of Oz frantically at his controls!! LMAO!!!

Holding an Aldis Lamp between his toes to synch the propellers! LOL

[Xrayist]

This may be a really ignorant question, but why not just use Curtis 4 blade electric props on all the engines?

[airnutz]

This may be a really ignorant question, but why not just use Curtis 4 blade electric props on all the engines?

I'd guess it had something to do with the Curtiss' reliability issues in extreme environments...don't want to put all the eggs in one basket? B29flteng also mentioned something about possible airframe harmonics issues...

[Pogmusic]

4 bladed were used on PB2Y-2 on. If the braking power were too far outboard, imagine how asymmetric the braking would be if you lost one of those "outboard" engines that had the 4 bladed prop.

[jdvoss]

As a point of interest I attached a google.earth image of former NAS Tanapag, Saipan, Mariana Islands. The two seaplane ramps can be readily identified when compared to the original picture at the beginning of this thread. The parking ramp now appears to have been replaced by possibly a power plant. When I visited Tanapag back in 1964 it was being used as a boat repair facility.