Looking to ID a De Havilland propeller blade

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Member for

19 years 4 months

Posts: 1,358

I am looking to ID a De Havilland propeller blade. It's just over 6 ft tall (185 cm), so it belongs to a prop of about 13 ft in diametre. It's engraved with drawing number DP55256/3.
I am suspecting it may be from a Lancaster, but have no way to confirm.

Original post

Member for

16 years 2 months

Posts: 2,841

Others on this forum may have a list of numbers allied to engine or airframe types, but not me. Can you post a pic?

Anon.

Member for

17 years

Posts: 1,037

It was only fitted to Wellington with Pegasus XVIII engines. Wasn’t fitted to any other types with a dH prop.

hope this helps.

Member for

19 years 4 months

Posts: 1,358

That's wonderful information, Fournier Boy, thank you very much.
If you don't mind me asking, how/where did you find out? A manual or actual engineering plans?

Anon, thanks, but a photo wouldn't have been too helpful as there were many more DH props with this shape. The number was the only way to be sure.

Member for

14 years 5 months

Posts: 3,447

I too am very interested in where this information is from. I have spent years building up a database of DH propeller numbers and profiles. Manuals never give blade profiles, but there are some Air Ministry partial lists of applications to type. Not seen one early enough to include bracket types before.

What I can state with certainty is that it's a 12' 6" left-hander.

The first five just says it's a bracket-type duralumin blade.
The second describes the shank size - this describes the diameter of the blade as it becomes circular in section at the root and enters the hub. This is a 5,000 series blade. This suggests a power range of between 900 and 1200 horsepower for a three-blader, but there were exceptions.
The third is the blade drawing number within the series - later this only indicated twist but in this series there were several basic patterns. The 200 type was the most widely used in the 5,000 series brackets. The Spitfire used the 400.
The fourth is hand of rotation - 0 for right, 5, for left. this is from a left-hander - ie probably a British radial, and definitely not Lancaster (right hand).
The fifth is how far the propeller is reduced in diameter from the 'master' drawing. In this case that's 6 inches - 3 inches per blade. The master drawing - and the blade 'blank' from the forge, would give a 13ft diameter propeller.

I have a spreadsheet that goes from the first brackets n the Mew Gull to the Hornet. the diameters are right, I have the Hamilton Standard designs that most were copied from, and now I have a lot of the profiles too.

But as I say, very interested in the source of the Wellington information. Do you have a list of bracket prop applications? I can give the profiles for them all. the info the OP has is partially correct - the 55256 had the same basic profile as the Lancaster, but 3 inches shorter and reversed. The Lancaster needle blade itself - a 455600 (the 4 prefix meant Hydromatic) was a copied Hamilton Standard 6353(hydro)/6105(bracket).

Member for

19 years 4 months

Posts: 1,358

That's fantastic information, thanks very much for explaining it here! I had guessed it was a 5000-series 13 ft DH prop, but that's where I got stuck. Great to learn about the science behind these numbers, thank you!

Member for

16 years 2 months

Posts: 2,841

Thanks, chaps. I tend to go on a picture as this allows me to i/d most of them. I haven't made a proper study of the numbers available (most people agree that props, especially UK de-H types, are a veritable minefield of varied and sometimes conflicting information) but others have, so thanks to FB and Beermat for their learned input.

A nice, early war time prop blade by the sounds of it, Skyraider3D. Is it in good condition?

Anon.

Member for

17 years

Posts: 1,037

Beermatt, I have the listings of what blades etc fit which hub installations.

PM your email address

FB

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16 years 2 months

Posts: 2,841

You could send that to me too, Fournier Boy, if you wouldn't mind?

Anon.

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16 years 2 months

Posts: 2,841

Thanks Skyraider. Nice blade. Any idea on where/when found?

Anon.

Member for

19 years 4 months

Posts: 1,358

Sadly no details of its origin survive, apart from that it came from a crash site in the Netherlands.