AD 644 and Lang LP 2100 & 2850 diameter and pitch?

[AndersJ]

Apparently the Lang LP 2850 was used on the Sopwith Camel both in combination with the 110 hp Le Rhone and 130 hp Clerget. Also the AD 644 seems to have been used in some cases.

For the Sopwith Triplane I have seen LP 2100 recorded as the propeller used.

I have however not been able to find information about the diameter and pitch for these propellers so I would be most grateful if someone could enlighten me on this point.

[regular122]

Originally Posted by AndersJ

Apparently the Lang LP 2850 was used on the Sopwith Camel both in combination with the 110 hp Le Rhone and 130 hp Clerget. Also the AD 644 seems to have been used in some cases.

For the Sopwith Triplane I have seen LP 2100 recorded as the propeller used.

I have however not been able to find information about the diameter and pitch for these propellers so I would be most grateful if someone could enlighten me on this point.

An original AD 644 belonging to John Shaw, marked for a 130hp, showed D - 2590 and P - 2650.

Two other examples, pictured below, also have the same data. The AB644 also has the same data.

As to the Lang LP 2850, an article snippet from WWI Aero shows it as D - 2590 and P - 2270. Lang apparently also used an L 3750 with D - 2560 and P - 2400.

I defer to the experts. Hopefully this helps narrow the search. Steve

[AndersJ]

Originally Posted by regular122

An original AD 644 belonging to John Shaw, marked for a 130hp, showed D - 2590 and P - 2650.

Two other examples, pictured below, also have the same data. The AB644 also has the same data.

As to the Lang LP 2850, an article snippet from WWI Aero shows it as D - 2590 and P - 2270. Lang apparently also used an L 3750 with D - 2560 and P - 2400.

I defer to the experts. Hopefully this helps narrow the search. Steve

This was just the type of information I was looking for so thanks a lot Steve!

I have been trying to understand the propeller selection for the Camel and in the attached table which is a snippet from British Air Board data from 1917, there are more entries with LP 2850 than AD644 and the former seems to have been more suited to the Clerget since it gave both higher top speed, climb rate and ceiling compared to the AD 644 even at roughly the same T/O weight of around 1480 lb.

Just as one would expect, the lower pitch LP 2850 propeller revs higher but the difference is not as large as I would have expected and it's interesting to note that the LP 2850 beats the AD 644 on both accounts.

Normally, I would have expected the lower pitch propeller to do better in climb and not be as fast and the reverse true for the higher pitch AD 644 but here interestingly the LP 2850 is simply better indicating that the AD 644 is a bit on the coarse side for a 130 hp Clerget.

At least that is my take on this unless someone has any other ideas about why they matched the AD644 with the 130 hp Clerget?

Best regards,

Anders

[YavorD]

Source: R. C. Gardner. British WW1 Aircraft Propellers (also pictures of a AD 644 Clerget Camel prop)

LP 2850
two blade, right-hand tractor propeller
Diameter 2590 mm
Pitch 2270 mm
130 HP Clerget or 150 HP BR1
Sopwith Camel

AD 644
two blade, right-hand tractor propeller
Diameter 2590 mm
Pitch 2650 mm
130 HP Clerget or 110 HP Le Rhône (also reported for 150 HP BR1)
Sopwith Camel
various makers (e.g. Ebora Type 106)

Reportedly AD 644 produced better performance in 1918, particularly with the "long stroke" Clerget.

[AndersJ]

Originally Posted by YavorD

Source: R. C. Gardner. British WW1 Aircraft Propellers (also pictures of a AD 644 Clerget Camel prop)

LP 2850
two blade, right-hand tractor propeller
Diameter 2590 mm
Pitch 2270 mm
130 HP Clerget or 150 HP BR1
Sopwith Camel

AD 644
two blade, right-hand tractor propeller
Diameter 2590 mm
Pitch 2650 mm
130 HP Clerget or 110 HP Le Rhône (also reported for 150 HP BR1)
Sopwith Camel
various makers (e.g. Ebora Type 106)

Reportedly AD 644 produced better performance in 1918, particularly with the "long stroke" Clerget.

Thank you Yavor!

Does that book say anything about LP 2100 used on the Sopwith Triplane?

[YavorD]

LP 2100
two blade, right-hand tractor propeller
Diameter 2740 mm
Pitch 2620 mm
110 HP Clerget or 130 HP Clerget
Sopwith Triplane

Source: R. C. Gardner. British WW1 Aircraft Propellers

[AndersJ]

Thanks again Yavor!