Information on Prop

[nathansmith]

Hi All,

I've inherited a propeller blade that I've been told is from a Lancaster, purchased from an antique shop in Newark in the late eighties. I've done a bit of research using the very knowledgeable people on this site. I've worked out that it's probably Rotol, right hand rotation and fitted to Bristol Hercules engines which could mean a number of aircraft. I wondered what else anyone could tell me from the pictures and description? Many thanks for any help or places/things to research in advance.

Prop:
190cm high (hub to tip)
Markings DB739, D48364, PB36 / 27, RA5813

 

[Wurger]

It is a wooden Rotol prop blade. The DB739 is the blade drawing number. The yellow disk with the "RA" says that the blade was made of spruce or douglas fir and covered with the Rotoloid. Its leading edge was armoured with the metal sheath. The three numbers in the yellow disk indicate the three-balde propeller. The numbers there are the serials of the blades. Your blade is the D48364 and therefore it is written with the larger fonts. The same number is repeated ( stamped ) on the blade adaptor ( the seventh image ). The RA5813 seems to be the adaptor drawing number and the PB36/27 the adaptor batch number. As memo serves, already there was somebody with a similar prop blade but of the DB734 number. It was associated with the Wellington. The length of your prop may indicate the Lancaster or just the Wellington. The Hercules-powered Lancasters Mk IIs were equipped with Rotol full feathering props with electric operation, and these had Jablo (wood) blades. So the Lanc is very likely too. But I would bet that's from the Vickers Wellington.


PS... just found via the net ... Genuine WWII Vickers Wellington Propeller | #425052708

 

[nathansmith]

Hi Wurger,

Thanks very much for the reply! Really interesting especially that the blade is part of a 3 blade prop. Are the DB numbers just the design of the blade, 739 signifying a newer design to 734? Also, I'm pleased to hear it might be from a Wellington (another family connection), am I correct in thinking that guess is based on numbers of Wellingtons with Bristol Hercules vs Lancasters with Hercules engines. Thanks for sharing your knowledge!

 

[Wurger]

Hello again,

Yes the DB number is the blade drawing number what is nothing more but the blade type. And yes the difference between the DB734 and DB739 may be the different shape, construction/material or the airfoil of the airscrew. Certainly it doesn't have to mean the 739 was improved variant of the 734. The prop blades were designed to get better efficiency depending on the engine power these were going to be used with and taking many more things into consideration. Also the prop blade data could vary because of manufacturers. It is because not only the Rotol Airscrews designed and made these blades but also the Weybridge factory. Because the drawing number starts with the DB, the Weybridge manufacturer is the one that made the blade. Please, see the first post with link below the pic here.
Regarding the guess on numbers of Wellingtons vs Lancasters with Hercules engine ... during the WW2 most of aircraft manufactures tried to standardize their products in order to be used for many different planes. Please make a focus on the late war Bf 109G. A such approach allowed to produce more parts by many other co-manufacturers. As a result the propellers could be used both for the Wellington and Lancaster for instance. So .. therefore it is logical that most parts remain from these most common planes. However it is not the rule of course.
The another matter is that the blade was bougth in a shop. How many prop blades used for relatively not too many of the Hercules powered Lancs could stay around until 80'? You don't have to be old enough to know how to make items more attractive for selling. The rarer item the higher price. Just a sales gimmick. Am I right?
To sum up ... if the Wellington kite has the family connection it can be a part from the aircraft type. But if the Lanc is also assiociated with your family it can be of the kite as well. Anyway the prop blade is a nice pice of the history. And if you want to keep the prop blade, it depends on you only what can be said about that. Nobody can say directly which particular plane the blade cames from. So ... you know. Just my opinion.

the pic source:

SpitfireSpares.com - warbird Propellers