Looking for info about a WW1 era propeller

[Roger Kloeck]

Hello,
I'm looking for more information of my wooden propeller of WW1.
I think the airplane is an AIRCO DH4
The following information is on the propeller:
DRG N° 2610 LH
D3050 P3740
R.R. EAGLE 8 G 1540 N 16
Questions:
Are there records that show which aircraft the propeller was fitted to?
Are there records that show the relatioships between motor and propeller?
What do the number on the propeller mean?

[Dave]

It's unlikely that you will find any documentation of the actual use of the propeller on specific aircraft. It's not unlike trying to track down a tire for a specific automobile.

The stamped information might indicate the following:

DRG N° 2610 LH = "Drawing number 2610, Left Hand"
D3050 P3740 = "Diameter 3050mm, Pitch 3240 mm"
R.R. EAGLE 8 G 1540 N 16 = "Rolls Royce Eagle 8", "G" "N" production numbers.


Unfortunately, I can't locate the specific drawing number to help identify the engine and possibly aircraft type that it might have been used on.

What is the basis for determining that it's for a DH4 aircraft? It might be correct, but I don't know what that basis is.

[Bob Gardner]

Good Morning Roger,

Dave's analogy to the impossibility of tracing individual tyres to a car is most appropriate. During WW1 new aircraft were manufactured with three props; one fitted and two spares. Large numbers were made under contract as additional spares, so it would seem that statistically each aircraft used between five and ten props in a comparatively short lifetime.

The G number on your prop indicates that it is just postwar and was built around mid-1919.

If family history says it is from a DH4 it's likely to be correct. The prop was fitted to various aircraft designed by de Havilland, including the DH4.

The drawing number was issued by the Army Board (the fore-runner of the Air Ministry) as AB2610 and was built under contract as AM2610 by the Aircraft Manufacturing Company (generally known as AIRCO), for whom de Havilland worked as a designer. It was also made by the Integral Propeller Company as IPC2610. At this time IPC was owned by AIRCO.

The prop was made for the Rolls Royce Eagle engine in various marks from 3 to 8 that were fitted to the DH4, DH4 with Mk 2 chassis, DH9, DH9A and DH10.

These props, although identical, were made under contract for specific AIRCO aircraft;
AB2610 Mk 8 Eagle DH4
AM2610 Mk 6,7 and 8 Eagles for DH4 Mk2, DH9A and DH10
IPC2610 Mk 3 Eagle for the DH4

So it is entirely possible that your prop came from a DH4 or the DH4 with the later Mk2 chassis.

AIRCO did not always add the letters AM to the drg no whereas the Army Board always added AB to theirs, so we can further assume that your prop was made by AIRCO and came from the DH4 with the Mk 2 chassis.

Are there any signs of a maker's decal on the blades? And are there any readable AID nos? These are usually found in a group of four very small boxes on a blade root near the hub. I would like to add these details to my database.

With kind regards,

Bob

[Roger Kloeck]

I found that information on this website:

www.crossandcockade.com/pdf/Propellers.pdf

The only thing that i don't understand is that it would have to be a 4-blade propeller. But when i looked up the Airco DH4, i found pictures of planes, some with 2, some with 4 blades. Does this have anything to do with the mk2 chassis? Is it correct to assume that the DH4's with the mk2 chassis only have 2-bladed propellers and the ones without the mk2 chassis have 4-bladed?

[Bob Gardner]

Hi Roger,

The Drg No 2610 props are all four bladed.

The DH4 was fitted with a variety of engines and both two and four bladed props. A quick run through my database shows that most RR Eagle 8 engines were fitted with four bladed props and all DH4's with the Eagle 8 engine had four-bladed props. There were several different drg nos for four bladed props for the DH4 in addition to yours, 2610.

The RR Eagle engine was geared to reduce the prop RPM to about 1100rpm which more or less doubled the torque at the prop shaft. Four blades reduced the span of the prop and because of the torque available the props had a very coarse pitch; in your prop a diameter of 3050mm with an 'oversquare' pitch of 3740mm. Typically a prop of 3000mm fitted to an ungeared engine in a bomber in 1917 would have a pitch around 2300-2400mm.

With kind regards,

Bob

[Roger Kloeck]

My propeller is 2-bladed. Are 4-bladed propellers made of two 2-bladed propellers attached to eachother? If fourbladed propellers were made of one piece, there would have to be signs of damage and there aren't any. I'm quite sure i read the numbers on the propeller correctly.

[Bob Gardner]

Roger,

My database shows AB2610, AM2610 and IPC 2610 as four bladed props. I have seen one of these props in real life and it does have four blades. They weren't made in two halves which was only a consideration used on USN and some RN ships.

I'll look thro' my database for some clues. I have seen some four blade hubs used as mementos where two blade roots have been skillfully removed.

Please post a photo of your prop and the data on it.

With regards,

Bob

[Bob Gardner]

Roger,

I have run through my database again. Almost all RR Eagle engines from Mk1 to Mk8 had four bladed props, irrespective of the type of aircraft. The very few exceptions are float planes or flying boats where presumably the engines were sufficiently above the water for the longer 2 bladed props to be able to operate.

My database mostly describes British DH4's and DH9's. Some were made for the States and some were built under licence in the States. These were equipped with Rolls Royce and Liberty engines and I have a note that a British experimental prop, drg no X3698, of 2 blades was fitted to a US DH4 with a RR Eagle 8 engine.

However, your prop has the correct diameter and pitch for the four bladed 2610 prop and I can't see an advantage in having two blades of these dimensions instead of four. A mystery. I hope you can show us some photographs.

Bob

[Roger Kloeck]

I have uploaded some pictures of my propeller on my photobucket. I will give you the link here:

http://s788.photobucket.com/albums/yy167/rogerkloeck/

I have also found some pictures on the net of DH4's with different propellers, one with a 2-bladed prop and another with two 2-bladed props fitted together as a 4-bladed prop.

http://www.historicaircraft.org/WW1-...rco-DH4-3.html

http://i479.photobucket.com/albums/r...McFEW/23-2.jpg

I have also posted this question on a different forum and someone there told me that there are DH4's with only 2-bladed propellers:

http://www.theaerodrome.com/forum/ca...airco-dh4.html

[Dave]

The thinness of the hub on your prop would suggest that it might in fact be part of a 4-blade combination, such as the one you located in that picture.

I have a 4 blade prop for a DH4 with the RR engine. I'll measure it and see if it's twice the thickness of yours.