DH9 Prop

[Rose]

I have an unrestored prop DH9 no: G1456N85 canvas still in place and mountings. Can anyone help me with its history?
Thank you

[Dbahnson]

When you say "its history" do you mean what specific airplane it was mounted on?

If so, it's extremely unlikely that you will be able to find that, and in fact you might find that it was never even mounted on one. If you can post a photo of the prop and a close up image of the hub, we can probably guess whether it was ever used or not by the presence or absence of "witness marks" caused by the pressure plate of the metal hub assembly.

Photos of the entire prop, the markings, and decals would also be useful.

[Bob Gardner]

Good Morning Rose,

The G number you have given us is a batch number. G1456 dates the prop to late 1919 or early 1920. These batches contained 100 props so yours was number 85 in this batch.

We need the data stamped on the sides of the hub to give you any more info.

With kind regards,

Bob

[Rose]

Thank you

I will post photos asap
I found more lettering on the other side
not 100% on all the letters but something like as follows

DE H9
200 HP SIDDERLEY
13HP
DRG 8B 7031

D 2750
P 2530

2 FURTHER STAMPS IN WOOD
Ican't read the top one other AID | AID
DFE | 37V

[Dbahnson]

I will post photos asap
I found more lettering on the other side
not 100% on all the letters but something like as follows

DE H9
200 HP SIDDERLEY
13HP
DRG 8B 7031

D 2750
P 2530

A picture of the stampings will help. It's almost certainly "AB" (for "Air Board") rather than "8B" for instance, and I can't imagine what the "13HP" would signify. I'll look through my reference materials when I get home (including Bob Gardner's books) which should help fill in some gaps.

In the meantime, you can at least confirm the accuracy of the "D" number, which should be the length from tip to tip in millimeters.

[Rose]

measured

yes 2750 tip to tip

[Rose]

Stamp photo

Might be 87V or B7V.

This prop has been in the shed since I was little. I have bought it in the house now and would like some advice on cleaning it. It is dirty. I have it stood on some foam to try and protect tip and will hang it later. I don't want to ruin it at all and my dad always kept it untouched
My mum had the other prop which is polished and hung on wall, that is from a Sopworth camel.

[Dbahnson]

Those are inspection stamps. Bob will be checking in within a few weeks and may be able to correlate them to a specific inspector.

See this thread about "restoration" for starters.

[racer2_uk]

Hi Rose and Dave,

"13HP" is likely to be "BHP" this came from Beardmore, Halford and Pullinger, 3 of the main men involved in the design and manufacture of the engine that this prop was designed for.


Andy

[Rose]

SE5a

I stand corrected by my mum she does not have a Sopworth camel she has a
SE5a prop on her wall.

[Rose]

The plate

From the plate on the prop would that have been the last engine it was fixed to?. I was going to remove the plate but perhaps I could leave it on and clean it up a bit. It is very oily.

[Dbahnson]

I'd leave it intact.

[Rose]

Engine

Thank you for engine info. Would the BHP engine be used for all of its life?

[Dbahnson]

Typically, if the propeller still has the metal hub attached it's most likely that it was used on that engine, removed for some reason, and never mounted on something different. But there's no way to be sure of the exact history.