Lockheed Hudson propeller

[noooby]

Hi there Hudson experts!

I recently found a prop blade in a museum that was labelled as Hudson, but is most certainly NOT Hudson (not a New Zealand museum).

Now I'm trying to convince them that it isn't Hudson, but in order for me to do that, I need a part number for the blade.

If it was a Hudson II with constant speed props, I would assume the hub would be Hamilton Standard 23E50 and the blade would be a Hamilton Standard 63xx series, but does anyone have a Hudson parts book and can check for me?

Oh and prop diameter too. This one is over 13ft in diameter, which sounds too big for Hudson.

Cheers!

Graham

[agalbraith]

Hi Graham, Denys I am sure will be able to confirm that. You are correct, sounds too big. Didn't the Corsair have a 13foot dia?

[noooby]

Yep and the Corsair used a 23E50 hub, which I'm thinking the Hudson II and onwards would have used too.

[curtiss]

According to the interchange manual Hudson blades are either 6379A-0 or 6339A-12. What is the P/N on the blade in the museum?

[noooby]

The blade in the museum is not a Hamilton Standard blade, but is a DH blade. Licenced copy, but different numbers. They do have some other unidentified blades that they are going to get details of for me and I'll try to identify them for them.

Thanks for the help!

Graham

[aircraftclocks]

This brings up a good point, does anyone have and cross references from DH to HS numbers?

[aircraftclocks]

I have the Hudson having a 23E50-109 propeller. The blades being P/N 6179 and the blade assembly being P/N 6179A.

[curtiss]

Is that for the P&W or cyclone powered aircraft? The AT18 manual ( TO 01-75KA-2)lists 23E50-285 with 6379A-0 blades , but I imagine there were a lot of alternates. If you can find a DH to HS cross reference manual it would be an amazing thing - I have been looking for a long time. I am beginning to think that such a manual doesnt exist.

[aircraftclocks]

My information comes from an RAAF document dated Oct 1941 on Hamilton propeller interchangeability.
The engine type is not stated, just whether it was a hydrostatic or constant speed unit.
The 23E50-109 is hydromatic, while the 23E50-311 is a constant speed unit.
For the latter, it is stated that the blade assembly is P/N 6157A/6, with either 6105 or 6157A blades if I have read it correctly.

DH made propellers in Australia, and it appears that their part numbers start with AP.

[noooby]

That cross reference is the holy grail for people looking for alternatives to DH propellers that aren't made anymore and drawings don't exist for.

I've been looking for a looooong time, and thought I'd struck gold when I found a US T.O for Hamilton Std propellers (T.O 03-20CC-4) that also had an RAF AP number (AP2121A&B) called Interchangeable Parts Catalog Hydromatic Propellers.

Alas, it does not deal with DH at all

Still looking.....

[davidd]

So far as I know, all Hamilton Standard 23E50 Hydromatic propellers "manufactured" in the UK by DH's were actually made up from parts made in the American factories and shipped to the UK under lend-lease, although the intention had originally been to manufacture them in the UK. Thus these "British made" propellers were mostly built up from all-American parts, but the hub components that had to "mate" with the British splines (which naturally were quite different to the American SAE splines) would have to be either modified after delivery from the USA, or DH's perhaps had to manufacture these particular parts themselves. In other words there probably has never been an "interchangeability" list for Hydromatic (NOT Hydrostatic!) 23E50 propellers made in the UK, which might explain why such a list is hard to find - the interchangeability list mentioned above probably lists alternative parts in the make-up of the American propellers (which were also in widespread use with the RAF anyway, in American aircraft such as Liberators, Catalinas, etc), thus the AP number. These props were very widely used on British aircraft, with the Lancaster, Mosquito, Stirling, Beaufighter, Flamingo, Albermarle and later Sunderlands springing immediately to mind. However the DH company DID manufacture THEIR OWN versions of Hydromatic propellers made on the Hydromatic principal but differing substantially in their dimensions and general appearance from American-made HS props, so no parts were interchangeable. These truly British props were used on Typhoons and Tempests and on some Lincolns, and probably all Bristol Freighters, Hastings, Devons, etc., and were made in 2, 3 and 4-blade variants, as the basic American model (the 23E50 as already mentioned) was originally only made in two and three-blade versions in the USA, although once such types as the B-26, B-29, P-47, P-51 and P-61 came along, they had to produce what the aircraft manufacturers required to turn RPM into thrust in the quantities required.
The earlier Hamilton Standard counterweight propeller (as used on Harvards, Beavers, Twin Beeches, etc), as manufactured both in the USA and UK, as well as other countries under license in 2, 3 and even 4-blade variants, such as Japan (and confusingly identified on this thread as "constant speed" propellers) were all more closely related than the later USA and UK versions of the Hydromatics. Hydromatics (which had a much wider pitch range than the earlier counterweight type, and could also incorporate the feathering function when fitted to multi-engine aircraft) also featured the constant speed refinement, which makes the use of this term to identify the earlier types of HS propellers rather meaningless, and confusing.
I hope all the above makes sense to readers, but these facts are searchable on the internet (and have been available in technical books for ever, although somewhat hard to find). An article was published in one of the British aviation mags in the 1950s (Flight of 2nd March 1956) on occasion of the 21st birthday of DH Propellers (or Airscrews as they were known at the time). This article, which covers most of the developments of this company, including the importation of the American parts to make up Hydromatics, as well as the development of the true British version of this type; apparently the manufacture of the British version was delayed considerably because American firms were unable to supply the required specialist machines (not produced in the UK) needed for production - see page 246 in the article.
David D

[noooby]

One thing to add, seeing as I'm working on a Typhoon..... The Typhoon prop hub, while listed under a DH number, is in fact a Hamilton Standard 33E60 (with a #6 spline), rather than the 5500 size 3 way Air Ministry Type 55/2 that DH says it should be!

I'm pulling the prop apart at the moment and the numbers stamped on the hub components have HS numbers not DH, even though DH made up their own numbers for all the bits and pieces anyway!

Hence the thought that there is a cross reference somewhere.

The 4 blade Typhoon may be a different story with the 4 blade DH prop (4000 size 4 way, D3/446/1), but there was also a 4 blade Rotol prop option for the Typhoon.


5000 size is the 23EX hub, which is the british equivalent of the 23E50. 5500 is the 33E60 in disguise. But then there was a 6000 size 3 blader (perhaps 43E60 equivalent?) as well.

With the

The HS numbers on the Typhoon prop also, interestingly, do not show up in the HS parts books, but they are most certainly HS numbers (52059 for a prop dome for instance, instead of the P40001A-2 that DH says the part number should be!).

[aircraftclocks]

David
I should not write posts on to forums when tired, and about to go to bed! Hydromatic is of course the correct name.
Following on from the various comments, my documents shows that the only parts with DH numbers were fitted to the 2B20-233 propeller. This is described as being fitted to the Wachett trainer, constant speed.

These parts are as follows:

AP-522A - Plug, Blade, assembly

AP-522 - Housing, blade, plug

AP-516/1 - Stud, blade plug

AGS-167/13 - Taper Pin, Blade Plug

A-2003 - Key Blade Index. 1 1/2° offset


To be fair, these look like minor parts, or standard in the case of the AGS item.

Now the bit that is much more interesting.....dated 1955?

A.A.P.717.00 Vol. 2, Part 1


PROPELLER INSTRUCTION NO. .02/4


Application: De Havilland Propeller Type 55/14 fitted to Beaufighter aircraft


INTERCHANGEABILITY OF BLADES


1. This instruction is introduced to eliminate the possibility of
 installing blades of different manufacture and weight to De Havilland 55/14 propellers.

2. Blades (Part Nos. P455960 and DP455960) manufactured by
 De Havilland, England, are of D.T.D.150 alloy and blades (Part No. AP455960) manufactured by De Havilland, Australia, are of 25ST alloy.

3. The difference in weight between the English and Australian
 blades is such that balance cannot be obtained with the propeller fitted with both types of blades.

4. Care to be taken when replacing damaged blades in 55/14 propellers that the replacement blades are of identical drawing number as those removed.

5. When painting serial numbers on the camber face of blades the
 prefix letters in full must be inserted.

This information will hopefully add a couple of pieces to the zig saw puzzle.

[nuuumannn]

The 23E50-109 is hydromatic, while the 23E50-311 is a constant speed unit.

I think we are getting a little confused here. 'Hydromatic' is a brand name coined by Ham Std for their pitch changing mechanism - it works by the use of differential oil pressure against a piston inside the hub, which actuates the blades via a moving cam. Constant speed refers to the governing of the propeller rpm at different engine power settings. The Hydromatic props, the 23E50 etc were nominally governed by constant speed units. These are not part of the propeller, but are driven by the engine.

Like Dave Duxbury stated, the Hydromatic props were different from the Ham Std counter weight props in that the counter weights provide force to actuate the pitch change of the blades. Bigger, more powerful aircraft engines were fitted with the Hydromatic props because the pitch range of the blades is greater and in larger aircraft there is sufficient range to provide a feathering capability.

I'm not 100 percent certain, but the main difference between the 23E50 and 23EX (the DH prop) is the splines on the spider (the bit which the props fit onto inside the outer casing) for attaching the prop to the engine prop shaft. Different props had different distributor valves (for distributing oil pressure to the piston in the hub) and breathers etc, but the basic internal mechanism of the two props was the same.

As for the blades, the basic blades could be cut to fit different aircraft and engine power outputs, i.e. the blades were chopped and shaped by hand - obviously the blade part numbers had to match, but if you had large prop blades and needed a shorter one for a different aircraft, you cut the thing and profiled it to match. I have a copy of the HS manual for the 23E50 somewhere, but I can't find it and it goes into different blade applications for each engine etc.

[emron]

Hi Graham,

Going back to your original topic the maximiun prop diameter on the Hudson / Lodestar / Ventura series is only 10'6". I'm not sure if the early DWG numbers for the Hudson blades still exist but I've found reference to Lodestar 6339A-12 which I gather is for the Wright engine and 6353A-30 for the P&W. If the museum blade collection is in a nearby Commonwealth country then I'd guess that larger blade is off something like a Bristol Freighter.

[davidd]

Interesting to see the information provided by "aircraftclocks" as this is the first time I have read anything on the Australian-built props, which also seem to be a blend of British and American technologies. Note that the part numbers for DH (UK) parts are prefixed by a simple "P" whereas the Australian equivalent is "AP" (presume the A added for Australia) and that the Australians are using a United States specification alloy for the blades rather than British. All new to me, but possibly not for some of our Australian members. Another thing perhaps worth mentioning is that HS (and DH) also eventually produced Hydromatic props for smaller engines/aircraft, including two-blade versions such as the ones fitted shortly postwar to NZ Aerial Mappings Beech AT-11 (ZK-AHO), and of course DH's in UK made the smaller props for Dove/Devon (3 bladers) and the Heron (2-bladers), so it was not only the bigger engines that benefitted from this advance in prop technology.
David D

[nuuumannn]

Yep, nice one Dave, the Beech's were about as small as the Yanks got with theirs, though. the counter weight props could easily deal with small types. The technology was a great idea and really upped the ante in terms of sophistication in the 30s; the basic concept is still in use in Hamilton Sundstrand props of today.

[denysjones]

Sorry I only just got around to looking at this so hopefully this is better late than never.

TO 01-75AB-2 for the Hudson III specifies the propellor as being HS a model 23E50-285 hub fitted with blade model 6379A-O and refers the reader to the HS TO's 03-20CC-1 and -2 for detailed info thereon.

hth

[davidd]

A little snippet I picked up many years ago is that the 23E50 Hydromatics used on Wright Cyclones (R-1820s) had a special addition to the "nose" of the dome in that a breather was incorporated, which looked a bit like a big flat button, quite obvious if the photographer was standing fairly close when the shutter was operated. However those fitted to P&W Twin Wasps (R-1830s) did NOT have this breather, as these engines had no use for them (or some such reason), although they DID have a type of nut head exposed there. The latter could be replaced by a lifting hook when required. I do not know whether the Wright and P&W variants had the same hydraulic dome, or separate domes for the two types. Grant may well have the answer in his extensive technical library. Also he may know if this peculiarity was continued with the later, larger variants of Wright and P&W engines, most of which also used 23E50 props (such as the TBF Avenger and its R-2600 Cyclone 14 - perhaps I should look at the one at Wigram!)
David D

[noooby]

Thanks for all the info. I knew from the get-go what it actually was and was able to positively identify it by the part number on it, but the Museum wanted specifics for the Hudson prop blades just to be absolutely sure before they changed their display.