Propeller blade identification needed

Denny Warwick

Recruit
4
0
Nov 27, 2022
I would like to know more information about a propeller blade (who made it, what year it was made, what type of plane it was used on, etc). Thanks for any help!

Aluminum propeller blade: There are several stamps on it that have "DHB"inside a round-cornered diamond shape. It is about 2m in length Numbering: OBAO 772/NA DRG NO DP 55256/3 N °1

Brass bushing/index plate: It has a brass bushing mounted to the shaft end having 38 rounded teeth Has "DHB" stamped inside a round-corned triangle Numbering: P5580 -1\2

This is likely a licensed, British-built (by de Havilland) copy of a Hamilton Standard propeller counterweight type propeller. The brass bushing with the 38 half round slots are the index numbers indicating the maximum high pitch the propeller is set to. The counterweight bracket aligned with those slots is set to 32 which will give the propeller a maximum high pitch of 32 which can be used to verify the aircraft/engine the propeller was used on.
 

Wurger

Siggy Master
Staff
Admin
Mod
94,010
18,480
Jun 19, 2005
Poland
The DHB indicates de Havilland, Broughton plant. The DP55256/3 is the drawing number, as memo serves.
 

Denny Warwick

Recruit
4
0
Nov 27, 2022
Welcome to the site.

A picture would be helpful.
Sorry about that, I meant to include with the original post. Here they are.
Prop Blade.jpg
Prop Gear.jpg
 

Wurger

Siggy Master
Staff
Admin
Mod
94,010
18,480
Jun 19, 2005
Poland
OK. THX.

You have posted that the blade length is about the 2m what seems to be over the 6ft. This indicates the prop diameter about 13ft. I'm not sure but according to my notes it was a blade prop used for a Wellington with Pegasus XVIII engines only. The DP55256 prop blades could be used for British radial engines of power 900 to 1200 hp.
 

Denny Warwick

Recruit
4
0
Nov 27, 2022
Thanks. Standing on the floor from floor to tip of the blade is 73 inches, no idea what the hub diameter is at the mount point but something like a 13 ft diameter seems right. So, the DP55256 is the model or type of prop? Did they put serial numbers or some type of data code on the prop?
Is there some kind of DHB lookup guide?
 

Wurger

Siggy Master
Staff
Admin
Mod
94,010
18,480
Jun 19, 2005
Poland
The DP55256 is the drawing number ( DRG) of the blade. It is not the serial or model of a prop.

Just found more details Looking to ID a De Havilland propeller blade

The meaning of the digits from left there ....

1. 5 says it's a bracket-type duralumin blade.
2. 5 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.
3. 2 is the blade drawing number within the series. The 200 type was the widely used in the 5,000 series brackets.
4. 5 is hand of rotation ... 0 - right, 5 - left. So it is a left-hander.
5. 6/3 says 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.

Is there some kind of DHB lookup guide?

Possible yes there is but I don't have that.
 

Denny Warwick

Recruit
4
0
Nov 27, 2022
Thanks much Wurger! That link to KeyAero has some good info. Are you a member there? If so, it would be great to connect with SkyRaider and Fournier Boy as it seems like he has the same type blade that I do, and Fournier Boy knows a lot about these props and has some additional information.

What exactly does the "bracket" look like (as this a bracket type blade)?

Standing in front of the plane, and looking at the propeller, is a left hand prop turning clockwise or counterclockwise?
Thanks!
 

Wurger

Siggy Master
Staff
Admin
Mod
94,010
18,480
Jun 19, 2005
Poland
I'm not the member of the KeyAero site. But if you want to tray to talk with the guys there please register to the forum.

From the point of standing you said , the blade left-hander ( left hand ) means the prop rotating clockwise.

As memo serves the "barcket" means tha the prop blade has a butt mounted at the blade root that comes into the hub/barrel that consisted of two halves ( the front and back one ). Both halves keep the prop blade(s) while screwed together just like the bracket. See the diagrams below.

The ‘bracket’ hub type ... actually that's the De Havilland one.
Image-Eight.jpg

the pic source: https://www.whirlwindfighterproject.co.uk/arm-waving-aerodynamics/

propeller_diagram_c.jpg


The Hydromatic hub type
propeller_diagram_a.jpg


propeller_diagram_b.jpg

the source: de Havilland Propellers
 

Users who are viewing this thread