Ham Std Variable Pitch Propeller

General information about the Wing42 Lockheed Vega.
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Tailspin45
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Ham Std Variable Pitch Propeller

Post by Tailspin45 » 23 Jun 2018, 23:34

More than you want to know about the Hamilton Standard S8460L propeller, a two-position variable pitch device that replaced the ground adjustable fixed pitch propeller made by the Standard Propeller Company(not yet merged with Hamilton).

Later, constant-speed propellers were introduced that would maintain engine RPM across a range of prop settings. Twin-engine aircraft eventually were fitted with constant-speed propellers that could also be feathered, but many early twins didn't have this extremely useful feature.

War Department-Technical Manual-Aircraft Propellers-Hamilton Standard Two-Position PDF 0.7Mb)

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Vitus
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Re: Ham Std Variable Pitch Propeller

Post by Vitus » 24 Jun 2018, 11:02

But didn't the first two-speed hubs work without the counter-weights? I'm pretty sure I saw a diagram of it showing that it used nothing more but oil pressure.
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Re: Ham Std Variable Pitch Propeller

Post by Tailspin45 » 24 Jun 2018, 17:51

Dunno how it would work without the counterweights to twist the prop back to fine pitch.

The idea, I believe, was to have the prop go to fine pitch in the event of loss of oil pressure.

The manual in the PDF link above shows the counterweights and describes their operation.

I'm guessing the prop you saw was a ground adjustable prop
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Re: Ham Std Variable Pitch Propeller

Post by Vitus » 24 Jun 2018, 18:58

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Re: Ham Std Variable Pitch Propeller

Post by Tailspin45 » 24 Jun 2018, 19:48

Good find! But....

Hydromatic props are variable pitch props, not controllable pitch props.

I know you know, but for the sake of others who may read this, the hierarchy of the complexity of aircraft propellers goes something like this:
Fixed Pitch
Adjustable Pitch (aka Ground Adjustable)
Controllable Pitch (aka Two-Position)
Variable Pitch (aka Variable Pitch ;))
Constant Speed (governor varies pitch setting to maintain constant RPM)
Feathering (pitch can be set so blade produces least drag with engine off)
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WW2 film describes types of propellers

Post by Tailspin45 » 24 Jun 2018, 21:53

Interesting vintage film. Some fussy diagrams about blade angle vs pitch but good comparison of types
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Re: Ham Std Variable Pitch Propeller

Post by Tailspin45 » 25 Jun 2018, 15:29

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Re: Ham Std Variable Pitch Propeller

Post by Tailspin45 » 25 Jun 2018, 15:30

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Re: Ham Std Variable Pitch Propeller

Post by Tailspin45 » 26 Jun 2018, 00:51

Boy, now I am really confused. Time for the artiste en residence to make a decision and go with what he thinks is right for this airplane. Lord knows it looks like every one was different.

I contacted one of the experts on aircraft propellers and this is what he wrote:
Hi Tom,

I have included a Hamilton Standard propeller listing for ground adjustable hubs. It's where the hub you listed S8406L from the TCDS should be referenced and it is not, see attached scan.

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The Fantasy of Flights Lockheed Vega has a Hamilton Standard 2D30 counterweight propeller, this propeller has the option for the 6101 blades (the 6101 blade is a D shank blade.)

I don't think the 2 model numbers from the type certificate are compatible as one propeller. The type certificate states, Controllable propeller (which would be the HS 2D30) which uses the 6101 blade. But the 6101 blade will not fit the original ground adjustable Lycoming Smith model P-220 propeller that was on the Vega (see Wiley Post's Vega below).

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