Identity for a Rotol wooden propeller

[aerotiques]

I'm trying to identify a Rotol(?) propeller. 59" tall with the serials and drawing number as shown… Any ideas?

 

[ThomasP]

The inspection stamps with the F H over M over the number xxx indicates the blade was made by F.Hills & Sons in Manchester (I think). As far as I know all F.Hills & Sons blades were made of Jablo wood.

The JT in the pink circle indicates it is covered with a layer of Thin Jablo, and it would have had a brass leading edge sheath as originally made.

The 303397 stamped on the adapter is the blade serial number, and with the other 3 numbers in the pink circle indicates it is one blade of a 4-blade prop.

 

[aerotiques]

The inspection stamps with the F H over M over the number xxx indicates the blade was made by F.Hills & Sons in Manchester (I think). As far as I know all F.Hills & Sons blades were made of Jablo wood.

The JT in the pink circle indicates it is covered with a layer of Thin Jablo, and it would have had a brass leading edge sheath as originally made.

The 303397 stamped on the adapter is the blade serial number, and with the other 3 numbers in the pink circle indicates it is one blade of a 4-blade prop.

Fantastic, exactly the type of reply I was hoping for, thank you! How could I identify what type of aircraft it might have been used on? Are there any other marks/serials I should look for?

 

[ThomasP]

If you can measure the overall length it might help eliminate some aircraft/narrow down the possibilities. I can not see the actual bottom of the adaptor in the photo, but I assume it is touching the wood base? For example, if the length is about 5' 1" or less it would not be from a Typhoon or Tempest, but could be from a Spitfire.

Otherwise, if you have not already done so, look for more stamp marks on the adaptor. There should be more stampings on the adaptor, either in the same section/area as the RA13718, or on the boss where the F H M inspection stamps are.

 

[Geoffrey Sinclair]

Quote from a person with an interest in propellers

"These enquiries have shed light on the factory marking of components which as far as I know is hardly documented. Thomas seems to have a good understanding of this, probably far better than mine. In his reply to the latest enquiry Thomas suggests measuring the blade height which would be a sensible thing to do in both (all) instances. A vertical from the base of the blade to the tip together with the height of the blade adapter would help in narrowing down the blade/aircraft identity.

I agree the second blade is Jablo from a 4-blade prop (thin Jablo covering with brass sheath). As Thomas observes, this is evident from the colour and coding of the disk. There is also a FH (F Hills) manufacturer stamp. I would make one minor correction though, in that the blade serial number on the adapter is electrically etched and not stamped as per above. As with the previous blade the rotation is left hand and therefore designed for a Bristol, Griffon or Sabre engined aircraft.

It does have the look of a 'fighter' blade."
End quote

 

[aerotiques]

Quote from a person with an interest in propellers

"These enquiries have shed light on the factory marking of components which as far as I know is hardly documented. Thomas seems to have a good understanding of this, probably far better than mine. In his reply to the latest enquiry Thomas suggests measuring the blade height which would be a sensible thing to do in both (all) instances. A vertical from the base of the blade to the tip together with the height of the blade adapter would help in narrowing down the blade/aircraft identity.

I agree the second blade is Jablo from a 4-blade prop (thin Jablo covering with brass sheath). As Thomas observes, this is evident from the colour and coding of the disk. There is also a FH (F Hills) manufacturer stamp. I would make one minor correction though, in that the blade serial number on the adapter is electrically etched and not stamped as per above. As with the previous blade the rotation is left hand and therefore designed for a Bristol, Griffon or Sabre engined aircraft.

It does have the look of a 'fighter' blade."
End quote

If you can measure the overall length it might help eliminate some aircraft/narrow down the possibilities. I can not see the actual bottom of the adaptor in the photo, but I assume it is touching the wood base? For example, if the length is about 5' 1" or less it would not be from a Typhoon or Tempest, but could be from a Spitfire.

Otherwise, if you have not already done so, look for more stamp marks on the adaptor. There should be more stampings on the adaptor, either in the same section/area as the RA13718, or on the boss where the F H M inspection stamps are.

I removed the wooden base, which revealed one additional inspection mark, namely 'FHM 81' and the serial number 303397 deeply etched into the base. Unfortunately, my phone battery then died, but I'll obtain some more pictures later. There are some more stamp marks on the adaptor and I'll photograph those too. It's 59 inches tall with the wooden base removed.

Thanks again for your help.

 

[ThomasP]

At 4'11" (59") it is almost certainly from a Spitfire or Seafire. Although I cannot say 100% for sure, I do not think that there were any other Allied aircraft that used a Rotol blade that short on a 4-blade prop. The early- to late-war Spitfire/Seafire had too little clearance to use a larger diameter prop. IIRC it was not until the very late Spitfire/Seafire that the prop blade length went over about 5' 3".

 

[Geoffrey Sinclair]

More propeller quotes:
"Regarding the second blade(latest link) armed with the further info, this is almost certainly a type RA10167 used on the Seafire Mk's 15 and 17. I will be interested to learn if this is corroborated by markings on the adapter. I have also just noticed that the specified fine pitch setting for this blade (27 d. 50 min) appears to be different to that which is lettered on the blade root (partly visible)

Perhaps therefore, I am wrong.

The other possible 4 blade Griffon Spitfire props(wood): Mk XII – blade RA10107 (although this is a rare bird so perhaps unlikely)"
End quote.

 

[aerotiques]

Here are the remaining images of all the visible markings on the root and adaptor…

 

[Geoffrey Sinclair]

More from someone who knows far more about the subject than I do.

"The most recent photographs confirm this is a Jablo blade. RA 13718 is probably the blade adapter type number.

As commented previously, the blade drawing number which was electrically etched onto the adapter is prone to fade/disappear with time and wear. Nevertheless, I can say from experience that a very close and careful examination may yield results.

This also applies to the blade base. In the case of Jablo blades there was often a board number and blade drawing number.

I somehow missed the measured blade height of 59 inches (assume base of adapter to tip). This has an implied propeller diameter of =/- 10ft 6ins which ties in with the 10ft 5ins for a Spitfire/Seafire Griffon 4-blade (wood) prop.

According to my research these are few in number:

Mk XII Spitfire – RA1017

Spitfire FR15/17 and Mk 15 Seafire – RA1067

Without the drawing number precise identification is, as they say, challenging.

In terms of making a visual identification the missing chunk of the leading edge is a hindrance.

The few photographs of the Mk XII show blades with a trailing edge base which may match that of the subject blade but there was also a dural blade which I am unable to differentiate.

As to the RA10167, photos of this blade (RA1067/RS)show a different lower blade profile (sharper/angular similar to the RA690 Spitfire V blade)so this looks less likely. Having said this, it seems details e.g tip could vary according to the finish e.g Rotaloid/Jablo. I can verify, for example that the RA690/RS has a different tip to the RA690/J, although the base is very similar if not identical.

I am also puzzled by the (part) fine pitch setting which doesn't seem to match my information.

Best advice on this one is for the owner to go to work with some white vinegar for cleaning and then a magnifying glass in the hope of finding a blade drawing number."

 

[SaparotRob]

I love these detective stories.