Warbird Information Exchange

Anyone know why they installed the four blade prop on Gil Macy's P-40 back in the 60s? I would have thought that original 3-bladers would have been pretty easy to come by then. What was the 4-blade prop off of? I also wonder how the extra blade may have affected CG.

Best I can tell, the four-bladed prop was put on this Hawk in the 50's. The aircraft was operated by B.H. Roberts of Continental Steel Buildings from 1950 to 1956, so this photo was more than likely taken during that period or perhaps shortly thereafter...


From Famous Aircraft - The P-40 Kittyhawk by Ernest McDowell, published by Arco

As to why... I dunno. That's something I'd like to know as well...


Fade to Black...

Maybe they dumped the electric prop and put a Ham Std on? You can probably add that to the mystery of why the canopy was changed.

Lots of odd things happened back when these were just cheap playtoys.

The 4 bladed prop actually looks like a Rotol metal unit as fitted to Hispano HA-1112-M1L Buchóns...

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Olivier Lacombe -- Harvard Mk.4 C-GBQB

It may have a second seat in it,Curtiss Electric props are verry over priced.
So most people now are looking at the Hamilton Standard you have to make a few mods under the spinner for the bigger dome.
But you are looking at 1/4 the price so it is worth it.
And the Hammy is a superior prop,it isn't going to run away on you like a Curtiss.

But you can change pitch with the Curtiss on the ground!

I don't care where you can change the pitch for $40-to $50.000 US.

Is this meant to be a joke, or am I missing something? Both the Curtiss Electric and Hamilton Standard are constant speed props, yes?

Now back to our regularly scheduled thread. Nobody has any idea why a 4-bladed unit was installed on the P-40 in question way back in the 50's?

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Dan Johnson

The electric vs hydromatic prop is as old as the propeller itself. I dont think either will ever win it. Both have advantages and disadvantages.

With a Curtiss Electric you can lose the governer and still control the pitch with the manual control. Very desirable. As for the 4 baded prop - I think they were all worth about the same back then - stuff was all around and nobody wanted it. Rumor has it that the Pilot (I'm not saying names) went trough a chain that was at the end of the run-way and ripped out the gear, etc. at Hollister. They put on the 4 blade prop that I think was off a P-51H because thats what they had. I don't know what they did with the spinner, but they did something. Again this is Rumor and what I've heard - I'm very sure it's very close to the real story. The new canopy was simply a "better design" by Continental Steel for a new back seat installation. Tom Camp changed it back to stock when he owned the airplane.

To clarify: With the engine switches in the OFF position.

bdk, thanks it makes much more sense now.

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Dan Johnson

I think he means that you don't need to have the engine running and producing hydraulic pressure with the Curtiss Electric to adjust the pitch of the prop. It has an electric motor which you can toggle the pitch of the prop with while only having the master switch on. That is what's cool about the Curtiss Electric, you can control it even if the engine stops running. In otherwords, feather that baby (if the motor doesn't have the stops in it - P-38 motor) if you suddenly find yourself in a glider . You Can't do that with a Ham Standard.

It's a price thing we won't be using them any more.

It's the laws of supply and demand. I thought a Ham Standard was going for 40K-50K anyway. I don't know where your gonna get a prop for 10K.