Lang props for F.1

[snj5]

Lang seems to be listed as making four propeller types for the Sopwith F.1:

LP 2850 and LP 2850m for the Clerget
LP 3640 and LP 3510 for the BR1

Were all of these the similar typical Lang angular wide waisted shape?
Any photos extant of these specific blade types?

Many thanks

[Bob Gardner]

'Morning Russ,

Lang and Sopwith were co-located and Lang was the preferred maker, so much so that Sopwith bought the Lang Prop Co in late 1917 when it became Sopwith's in-house prop shop, althought it retained its name, Lang.

The Air Board was set up in late 1917 in preparation for when the RNAS and the RFC merged into the Royal Air Force in April 1918. The Air Board held a competition to find the best Camel prop for the 130hp Clerget and the Navy design AD644 turned out to be slightly better than Sopwith's own Lang prop, LP2850. But both became standard props (ie; prop of choice) from November 1917 to the end of the war in late 1918. The majority of surviving Camel props that I have seen are AD644. LP2850 was also the standard prop for the BR1 engine from November 1917 to February 1918.

LP3640 was the standard prop for both F.1 and 2F.1 with the 150hp AR1 and BR1 and was also tried experimentally with the 150hp Gnome Mono.

LP5440 was used experimentally with the 180hp Le Rhone.

LP3510 replaced LP LP2850 as the standard prop for the BR1 in February 1918.

There were several other AB and AD designed props for the Camel.

I don't have photographs of any surviving Camel props other than AD644 but almost all Lang props were of the usual angular shape, the few exceptions being French props built under licence by Lang and given a Lang drg no. (Afternote; see below)

With kind regards,

Bob

[Bob Gardner]

Russ,

Contrary to what I have written above, I have just found photographs of LP3640, used with the AR and BR1 which is of French design.

Bob

[snj5]

Many thanks, Bob.

As I have read, the Lang props were popular with some crews preferring them over the AD644 for a perceived better rate of climb ( e.g. Winged Victory - Yeates). Interestingly, the LP 2850and LP 3640 had a shallower pitch as compared with the AD644, indeed making it a better climb propeller.

Interesting how documents sometimes bear out anecdotal stories.

I really would like to see what a LP 2850 looked like. any other places to look? I am wondering if it is the more narrow necked club looking propeller you see in some Camel pictures.

Again, Many thanks!!

[Bob Gardner]

'Morning Russ,

I expect you are correct that LP 2850 is visible in many Camel photographs, but sadly I have never seen LP2850 nor found a photograph of one. My research is based on documents published at the time, examples in Museums and props that I have bought and sold, so there are large holes in my knowledge, waiting to be filled in!

Bob

[snj5]

Bob

Attached is my best candidate for the LP 2850. The unique Lang shield decal is visible on the blade, and it's certainly not an AD644. The shape is reminiscent of the more typical Lang, with the wide center. This propeller shape is not uncommon in F.1 drawings and photos, but is captured here with the Lang decal.

Best regards
Russ

[Bob Gardner]

Russ,

Interesting. This also is a prop of French design and on checking my two reference books I have failed to discover any photograph of the usual angular Lang prop as used on the Sopwith Strutter (see photo below). So perhaps the Camel only had French designed props made under licence by Lang? I have ordered two more Camel books from Amazon to try and increase my knowledge on the subject.

Bob

[snj5]

Bob,

Hopefully you have ordered "The Camel File" by Sturtivant and Page. Beginning on ppg 254, their drawings show props as in my photo previous; a single sided Lang decal (as was their frequent application) is visible, and the notes even identifies them as a Lang propellers.

Best
Russ