Another propeller hub item to ID, please

[Larrythepilot]

Here is another prop hub item that Joe Clegg has cleaned up. It is perhaps a propeller governor part? 2 pictures are attached. The number on the end of the shaft is 74147. Joe didn't see any other numbers . Any idea what prop it is from? What airplane(s) it might have been used on? Thanks for your help.
Larry

 

[mjfur]

I'm not seeing a prop hub. Where do the blades attach? What does the other side and bottom look like?

 

[Larrythepilot]

I have asked Joe for additional pictures. I'll post them when I get them. Thanks for the response.

Larry

 

[cammerjeff]

It looks more like a propeller governor to my eyes, defiantly not a Hub. But it could be part of a number of engine driven accessories. Defiantly will need more pictures to narrow it down.

 

[Engineman]

Hi Larry,

That is obviously the actuating cylinder for the 4-Bladed early H-S type copy propeller that I have already identified as likely the Japanese development.
You can see that the cylinder in your picture has 4 output drive pins to the blades.
Compare to the usual early H-S 3-Blade operating cylinder in this photo, similar but with just 3 blade pins .
Cheers

Eng

 

[Engineman]

Here is that photo of the Japanese G4M2 with the early H-S 4 Blade development again.

Cheers
Eng

 

[Larrythepilot]

OK, thank you Engineman. With your research and several responses to my inquiry, I believe we have sufficient information to create an intelligent exhibit sign to go with the propeller hub, spider, and governor cylinder parts we are cleaning up. After we finish cleaning and assembly, I'll post a picture of the display in our museum. ..... Larry

 

[Engineman]

OK, thank you Engineman. With your research and several responses to my inquiry, I believe we have sufficient information to create an intelligent exhibit sign to go with the propeller hub, spider, and governor cylinder parts we are cleaning up. After we finish cleaning and assembly, I'll post a picture of the display in our museum. ..... Larry

Thanks Larry,
Yes, the part you show is the hydraulic operating cylinder, it moves the blades in pitch. It is not a governor, that is a bum steer!

Eng

 

[MiTasol]

For a better understanding of the whole prop I have PMd you a three bladed counterweight manual. I will post a couple of prop manuals for all as soon as I get a chance to finish them.

 

[Larrythepilot]

OK, thank you for the additional information.

Are the H-S counterweight props just variable pitch, but not constant speed? I understand modern props with governors, that maintain a constant engine rpm by changing the prop pitch; hence "governor". I know some older props were just variable pitch, and the pilot had to fuss with throttle setting and prop pitch to get the desired result. Years ago I flew a small plane with and electric pitch control. It had only two positions; high-pitch (for cruise), and low-pitch (for takeoff and landing).

Thanks,
Larry

 

[Engineman]

Hi Larry,

The earliest VP props that were adjustable pitch in flight were really the 2-position, coarse/fine type. The advantages of multi-pitch range adjustment rapidly followed, the
facilitating factor being primarily the design of operating controls and oil valves etc to achieve incremental adjustment. Further advances were to achieve the concept of variable
propeller (engine) speed control with pitch change and the critical factor here was the design of variable datum flyweight governor to suit, so becoming a Constant Speed system.
At the same time, the early VP props, like the counterweight H-S, were recognised for the small pitch range that did not fully suit high speed aircraft, nor did it facilitate full feathering for engine failure assistance in multi-engine types. The development of greater pitch-range VP props naturally followed.
The H-S counterweight type prop could have operated as a simple 2-position prop, but I suspect that it really fell into the adjustable multi-pitch type initially, rapidly being
adopted as a Constant Speed system.
The specific operation method depended on the aircraft installation. In the Battle of Britain, De Havilland licensed versions of the H-S counterweight prop operating in the
Constant Speed method were used by the British.
Many other detailed applications of the H-S counterweight prop existed.

Eng

 

[MiTasol]

Hi Larry,

The earliest VP props that were adjustable pitch in flight were really the 2-position, coarse/fine type. The advantages of multi-pitch range adjustment rapidly followed, the
facilitating factor being primarily the design of operating controls and oil valves etc to achieve incremental adjustment. Further advances were to achieve the concept of variable
propeller (engine) speed control with pitch change and the critical factor here was the design of variable datum flyweight governor to suit, so becoming a Constant Speed system.
At the same time, the early VP props, like the counterweight H-S, were recognised for the small pitch range that did not fully suit high speed aircraft, nor did it facilitate full feathering for engine failure assistance in multi-engine types. The development of greater pitch-range VP props naturally followed.
The H-S counterweight type prop could have operated as a simple 2-position prop, but I suspect that it really fell into the adjustable multi-pitch type initially, rapidly being
adopted as a Constant Speed system.
The specific operation method depended on the aircraft installation. In the Battle of Britain, De Havilland licensed versions of the H-S counterweight prop operating in the
Constant Speed method were used by the British.
Many other detailed applications of the H-S counterweight prop existed.

Eng

A great summary but dH were actually licence building H-S counterweight props for the Blenheim as early as early 1936 and I think the Blenheim's forefather, the type 142, had dH counterweight props on its first flight in April 35.

All the early dH built H-S props were fitted to engines with two position controls such as the Merlin II thru V and the early Pegasus and Mercury as fitted to a number of aircraft up to and including the Blenheim Mk I, Lysander Mk I and Sunderland Mk I.

 

[Engineman]

A great summary but dH were actually licence building H-S counterweight props for the Blenheim as early as early 1936 and I think the Blenheim's forefather, the type 142, had dH counterweight props on its first flight in April 35.

All the early dH built H-S props were fitted to engines with two position controls such as the Merlin II thru V and the early Pegasus and Mercury as fitted to a number of aircraft up to and including the Blenheim Mk I, Lysander Mk I and Sunderland Mk I.

Thanks.
I quote the Spitfire installation of the Constant Speed H-S propeller system as just-in-time for the BoB (effective on the front-line by about June 1940) as an indication of the
state of the art in actual combat aircraft at that time. I think this actual adaptation of the H-S counterweight in a Constant-Speed system was possibly the first in the UK.
Of interest, there was some argument about the value and problems with the Constant-Speed prop in the RAF before its introduction, but sense prevailed, unlike the RAF Fighter tactics in 1939.
True Constant-Speed installation dates for other H-S counterweight props and the types would be interesting.

Cheers

Eng

 

[Larrythepilot]

Hi Larry,

The earliest VP props that were adjustable pitch in flight were really the 2-position, coarse/fine type. The advantages of multi-pitch range adjustment rapidly followed, the
facilitating factor being primarily the design of operating controls and oil valves etc to achieve incremental adjustment. Further advances were to achieve the concept of variable
propeller (engine) speed control with pitch change and the critical factor here was the design of variable datum flyweight governor to suit, so becoming a Constant Speed system.
At the same time, the early VP props, like the counterweight H-S, were recognised for the small pitch range that did not fully suit high speed aircraft, nor did it facilitate full feathering for engine failure assistance in multi-engine types. The development of greater pitch-range VP props naturally followed.
The H-S counterweight type prop could have operated as a simple 2-position prop, but I suspect that it really fell into the adjustable multi-pitch type initially, rapidly being
adopted as a Constant Speed system.
The specific operation method depended on the aircraft installation. In the Battle of Britain, De Havilland licensed versions of the H-S counterweight prop operating in the
Constant Speed method were used by the British.
Many other detailed applications of the H-S counterweight prop existed.

Eng

Thank you for the explanation, Eng. Now I better understand what was going on at the time.

Larry

 

[Engineman]

Thank you for the explanation, Eng. Now I better understand what was going on at the time.

Larry

Hi Larry,

As you know, there were several types of Variable Pitch propeller designs that became popular in the 1930's. The developments of oil operated V.P. propellers by Hamilton Standard starting in about 1929, and being common in the USA by the mid 1930's, were perhaps the market leaders. Certainly, you can see the widespread license versions all around the world. The further developments in other companies and nations were catalysed by the H-S lead, although several other companies avoided license purchase by different designs.
Possibly to avoid license costs and to achieve changes in functionality, electric operated instead of oil operated V.P. propellers were developed by several companies such as VDM, Ratier
and Curtiss. These were also copied or licensed.
Variable-Pitch Constant-Speed propellers were a great technological step in aircraft performance, ranking alongside Supercharging, high-Octane fuels, Fuel-Injection and Pressure Carburettors for the big steps forward in about 1930 to 1940, IMO.

Cheers

Eng