Propeller blade identification

[heydon]

Hi everyone,

I recently purchased this propeller blade, based on the hub no RA5812 it was typically used on Hurricanes, Baracudas and possibly Beaufughters too.

Their are other serial no markings on the ring: T-169/12 and then on the base of the hub: JP33242

Can anyone from this help me determine the specific aircraft this was used on?

Length of prop from bottom of extended hub pins to top of blade is 1.67m and width at widest part of chord is about 28cm

What I've found so far:
1. Manufactured by Jalbo (JP33242)
2. Spruce, Covered by Rotoloid and Armoured (not brass) (RA 55812)
3. Tip has extra armour not just on the leading edge

Can't get info on other numbers T-169/12, could be a drawing number or manufacture date serial number?

I'm assuming 3 blade spitfire or hurricane?

 

[heydon]

Anyone got any info and n above for me?

 

[Wurger]

Hello,

I'm afraid it is not possible to determinate which particular aircraft the prop blade was used with. The RA.5812 adaptor could be fitted to a large number of hubs. In other ways the adaptor was used on almost anything you could dangle a Merlin off on. The T-169/12 is not the drawing number rather. The marking should start with the RA letters.

Add.1 ... not Jalbo manufacturer but Jablo one what indicates the JP33242 number. A typo I guess. The full name of the manufacturer was the Jablo Propeller Ltd, a propeller manufacturing company which was owned by Rotol also known as the F. Hills & Son Limited, in Manchester. So in general it is the Rotol prop blade.

Add.2 ... You stated " Armoured (not brass) " .. actually I can't see any correct in shape sheath for the protection of the leading edge. The Rotol blades could be either without the "armour" or of the brass or of the steel one. Usually, the armour consisted of a couple of short pieces screwed to the leading edge making a kind of a strip protecting the leading edge from about 3/4 blade span to its tip. But always at the leading edge only. See the pics below. So the upper part of the armour of your blade isn't the correct one IMHO. The blade seems to be a used as a stand for someting and had to be reworked. What is more, it seems that the blade general shape was changed at the upper half at the trailing edge. A pic of the another side would be useful as well.

 

[heydon]

Hi Jurgen, thank you.

I will send a pic of the other side too.

The armour on the leading edge does run by he entire length, I can see the indentations under the Rotoloid covering.

On another forum I picked up a problem ctire of the nomenclature explanations where it stares that the 'A' in the RA relates to an Armoured sheath - but probably brass, I was assuming that Simple in the RS was possibly brass and Armoured would then be another harder material?

 

[Wurger]

The RA marking changed in time. Initially the RA in the disk meant, the "R" the kind of the covering ( Rotoloid or Rayoid ) and "A" meant the steel sheath ( later just Armoured, no matter if of the brass or steel ). But unfortunately your blade doesn't have the marking that should be at the blade root above the metal adaptor. The marking was applied on the black covering of the prop blade. Usually there was the RA ( drawing number of the blade ) above the disk. Also in the disk there could be listed all serials of all the blades the prop consisted of. The colour of the disk indicated the kind of wood the prop blade was made or the manufacturer.
And a note though ... the "RA" marking on the hub adaptor is not the same what the "RA" one on the prop blade.

 

[heydon]

See full leading edge

The RA marking changed in time. Initially the RA in the disk meant, the "R" the kind of the covering ( Rotoloid or Rayoid ) and "A" meant the armour of the steel ( later just Armoured, no matter if of the brass or steel ). But unfortunately your blade doesn't have the marking that should be at the blade root above the metal adaptor. The marking was applied on the black covering of the prop blade. Usually there was the RA ( drawing number of the blade ) above the disk. Also in the disk there were listed all serials of all the blades the prop consisted of, very often. The colour of the disk indicated the kind of wood the prop blade was made or the manufacturer.

View attachment 762207

Thank you Siggy, I saw this too, but because I don't have the disc marking - I suppose it's a dead end. However, if I look under the yellow paint onbtje tip, it's defnately steel. I'm therefore assuming that it would have had a white disc, meaning an early blade. Am I right in this assumption?

 

[Wurger]

IMHO you may be right. But the pink also could be.

 

[heydon]

IMHO you may be right. But the pink also could be.

Thanks Wurger - Did the pic on the right not replace the one the left? If so, then naybe I'm onto something. Still a long shot in the dark..

 

[Wurger]

Thanks Wurger - Did the pic on the right not replace the one the left? If so, then naybe I'm onto something. Still a long shot in the dark..

Not exactly ... the colour indicates the manufacturer mostly. The white disk is said to be of the Rotol Airscrew Ltd , the yellow of the Weybridge one. The red-pink disk indicated the jablo wood. Rotol Airscrew Ltd made the blades of the jablo wood but they used the white disk. The Weybridge factory used the spruce wood and used the yellow. The another manufacturer who made the blades of the jablo wood was just the F. Hills & Son Limited ( orginally the Jablo Propeller Ltd) one. Because the JP number indicates the F.Hills factory it might have been of the redish pink colour. In your first pic of the blade I can see the factory inspection stamps on left and next to the T-169/12 number. How do these look like? Are there the FHM letters in the ring accidentally? See image below ...

 

[heydon]

Not exactly ... the colour indicates the manufacturer mostly. The white disk is said to be of the Rotol Airscrew Ltd , the yellow of the Weybridge one. The red-pink disk indicated the jablo wood. Rotol Airscrew Ltd made the blades of the jablo wood but they used the white disk. The Weybridge factory used the spruce wood and used the yellow. The another manufacturer who made the blades of the jablo wood was just the F. Hills & Son Limited ( orginally the Jablo Propeller Ltd) one. Because the JP number indicates the F.Hills factory it might have been of the redish pink colour. In your first pic of the blade I can see the factory inspection stamps on left and next to the T-169/12 number. How do these look like? Are there the FHM letters in the ring accidentally? See image below ...

View attachment 762229

That's great insight Wurger. I've attached a pic of the factory stamps. Hard to make out…

 

[Wurger]

You got it flipped . Here is rotated shot. Can you see the F. letter in the mid stamp? And below the comparing of the two shots. The layout may be different but I think it is of the F. Hills & Son Limited factory.

 

[heydon]

Agreed! I found some interesting info on the factories and use of Christofin and not Rotoloid, also a mixture of brass or steel armour on the leading edge…

Compressed Wood Propeller Blades

THE USE Of WOOD FOR AIRCRAFT IN THE UNITED KINGDOM Report of the forest Products Mission June 1944 Three types of propellers made from compressed wood are now in production in the United Kingdom and several other types are in various stages of development. Fixed-pitch, wood propellers of conventi...

www.britmodeller.com

 

[Wurger]

Yes the Cristiofin covering can't be excluded.

But there is another thing .. the blade length. You stated above it's 167cm long. It is about 66 inches or 5ft and ~6 inches. So the prop diameter would be about 334cm ( 10ft and 11.5 ins ). without the prop hub. With the hub it could be about 11ft and 6in. to 12ft or so. I'm not sure if it is not too large for the Spitfire or Hurricane.

 

[heydon]

Yes the Cristiofin covering can't be excluded.

But there is another thing .. the blade length. You stated above it's 167cm long. It is about 66 inches or 5ft and ~6 inches. So the prop diameter would be about 334cm ( 10ft and 11.5 ins ). without the prop hub. With the hub it could be about 11ft and 6in. to 12ft or so. I'm not sure if it is not too large for the Spitfire or Hurricane.

Hi Wurger, the 167 is from the tip to the bottom of the hub inserts. The other option is possibly the Halifax bomber. But there were none of these in South Africa, unless it was maybe brought back from N Africa or Italy?

 

[heydon]

Or a Beaufighter?

 

[heydon]

Hi Wurger, the 167 is from the tip to the bottom of the hub inserts. The other option is possibly the Halifax bomber. But there were none of these in South Africa, unless it was maybe brought back from N Africa or Italy?

Both Beaufighter and Halifax seem to have rounded tips. The other alternative is the Hurricane - which could explain the wide chord…and the blade shape is similar.

 

[Wurger]

The RA number of the hub adaptor says it is for the Merlin engine. Both the Halifax and the Beaufighter in your pics above have the metal Hamillton Standard props and aren't powered by the RR Merlin unit.
Regarding the Hurricane .. as I had mentioned it previously, I'm not sure if the diameter of the prop for the Hurricane could vary from 11ft 6ins to the 12ft. IIRC the Hurricane IIB Rotol prop diameter was of 11ft and 3ins and the prop blade lenght was 4ft and 11 inches ( 59" ). A such larger diameter indicates the Typhoon rather. What is more the Hurricane prop in the pic above seems to have more pointy blades with quite wide roots.

 

[heydon]

mmm….aluminium makes sense. I'll look for other pics.

Did Typhoon use Jablo blades…I'll do some research in that direction.

 

[heydon]

mmm….aluminium makes sense. I'll look for other pics.

Did Typhoon use Jablo blades…I'll do some research in that direction.

Seems the Typhoon used a Napier Sabre engine and not Merlin.

 

[Wurger]

The Beaufighter Mk.IIF with the Merlin engines. Looking familiar? Please notice in the second pic that the armour is extended from the balde tip to the almost bottom part similar like for your blade.

source: Bristol Beaufighter Mk IIF - Destination's Journey