Prop with no markings

[tnowak]

Greetings,

A friend of mine's old aunty has a propeller which belonged to her late husband. She is considering disposing of it and wondered if I could help identify it. Although I fly a classic aeroplane (Piper Vagabond) I am not an expert with "old" propellers so am looking for help. Firstly, the details:
1. No markings whatsoever on prop
2. Diameter = 80 inches
3. Hub thickness = 4 inches
4. Prop bolt holes = 0.6 inch dia (qty
5. Hub diameter = 9 inches
6. Rotation (viewed from front): counterclockwise

Pictures at: http://s361.photobucket.com/albums/oo53/tonnowa/

Hub dimensions appear to be fairly standard (having looked at the Sensenich hub page). I haven't seen the prop myself and the measurements have been passed to me by the aunty. May need to be doublechecked!

Any thoughts as to possible engine / aircraft? You will note that the leading edge of the blades sits forward of the hub.

Regards
Tony

[Dave]

Without markings it's almost always just a wild guess. The leading edge protusion is unusual, but is similar to this propeller...

[Bob Gardner]

Good Morning Tony,

The prop has all the hallmarks of a design by Dr HC Watts of the Airscrew Company of Weybridge. Flight magazine observed that they produced 80% of British wooden props between the wars. They continued making wooden props until the 1970's.

In the mid 1930's they stopped stamping the data on the hub and instead screwed a small brass plate near the hub. These are often missing these days but traces of four screw holes can sometimes be found, describing a plate about about 2 inches by 1.5 inches, often located on or near those raised humps either side of the hub.

An 80 inch diameter (6.66ft or 2030mm) suggests a light aircraft. Possibilities include drg no Z 8010 for an Auster, and Z 6011 for a DH Moth, both of which had DH Gypsy engines, but the best candidate is a DH Tiger Moth with a Gypsy Major engine, where the prop is listed as 6.67ft, drg no Z 6013/1/A . Large nos of Tigers were made as training aircraft during WW2, so statistical chance reinforces this liklihood.

They are fairly common in GB and sell for about 250 gbp at auction.

With regards,

Bob

[Dave]

Bob, weren't the Gypsy engines Left Hand rotation?

This one is Right Hand.

[tnowak]

Bob,

Before seeing pictures of the prop I assumed it would be for an Auster / Moth or similar. However, seeing it was for a CCW rotation engine made me think it would be for something quite different.

I know that some Austers have Lycoming engines, but the prop style and size doesn't seem to make that likely.

I have asked the the prop to be examined for screw holes.

Any thoughts as to what engines of that "prop era" are CCW rotation? I believe some license made Cirrus/Gipsy engine in USA rotate in that direction.
Tony

[Bob Gardner]

Hello Tony,

I can't offer any help along these lines, really. I don't know much about engines.

The prop is a Watts design and the diameter matches drg no Z 6013/1/A. This is the limit of my ability. I am slowly building up a database of Watts drg nos. Sadly they threw all their archives away when they closed their prop dept in the 1970's.

Let me know if you discover anything else.

Bob

[Bob Gardner]

As a postscript, the thought occurs that Gypsy engines might have been handed for use in two engined aircraft?

Bob

[tnowak]

I asked my friend to ask his aunty to check for four small screw holes. Well, aunty's eyesight must have improved (!) as she found 7 lines of information on the back of the prop!

2nd line reads DRG 0 581/1
3rd line reads WASP 2 JUNIOR
6th line reads D7 25 1791
7th line [very hard to read] it could say 777

So, I assume the prop is for a Wasp 2 Junior radial.

Any other useful history info from the above technical data?

Typical value now?

Regards
Tony

[tnowak]

I asked my friend to ask his aunty to check for four small screw holes. Well, aunty's eyesight must have improved (!) as she found 7 lines of information on the back of the prop!

2nd line reads DRG 0 581/1
3rd line reads WASP 2 JUNIOR
6th line reads D7 25 1791
7th line [very hard to read] it could say 777

So, I assume the prop is for a Wasp 2 Junior radial.

Any other useful history info from the above technical data?

Typical value now?

Regards
Tony

[Bob Gardner]

This becomes more difficult. I don't have any data for a British fixed pitch prop made for the P & W Wasp Junior. This engine was powerful, 450hp onwards, and probably was only used with a variable pitch prop. However fixed pitch props might have been used on RAF Ansons, Oxfords and the Northrop Nomad taken over from a French order.

I'll do a bit more research and come back.

Bob

[Bob Gardner]

I have found out a little more but not much. The Avro Anson and Airspeed Oxford both used the PW Wasp Junior. Two thousand Ansons were built in Canada with this engine. But I think the props for these would have been a different shape from a Watts prop, having been made locally in Canada.

The diameter of 7.25ft is close to the diameter of the Watts prop fitted to the Cheetah engine in the Anson and Oxford, which used fixed pitch props.

My guess is that yours is one of a limited run of props made by Watts for the Wasp Junior engine which might have turned up in Britain on the occasional ac requisioned by the RAF such as a Staggerwing, A17, Beechcraft Expeditor, Goose and Lockheed 10 and 12A's or for Canadian Ansons and Oxfords, if any of those got to Britain.

[tnowak]

Hi Bob,

I am still trying to figure out which airframe this prop may have been for. Can you by any chance tell from the Dwg No. or any other info I provided the approximate year the prop would have been manufactured?

You mentioned "mid 1930s" a few posts back when they stopped stamping info on the hub. Does that suggest this prop was manufactured pre 1930s?

Regards

Tony

[Bob Gardner]

Good Morning Tony,

I can't offer much more help. My intuitive feel is that the prop dates from WW2. It's a British prop. British aircraft with a Wasp Junior engine are rare. If Watts drg nos are sequential (they do seem to be) your prop was designed around 1939-40 and probably the design remained in use throughout the war. Those last three digits (777) might possibly be a date of manufacture and if so would be written in the format, for example, 7.42 or 7/42 indicating July 1942.

I suggest that some hours googling might produce a result (it often doesn't). It might produce RAF aircraft which used the P&W Wasp Junior engine. It might find a photo of such an aircraft on the ground where you can compare your prop with the prop on the aircraft. This probably won't give a definitive answer but might give you a shortlist of possibilities.

If you discover anything, please let us know on this forum.

With regards,

Bob

[tnowak]

Hi Bob,

Well, have spent a good few hours Googling and think I have identified the likely airframe - an Airspeed Oxford.
As far as I can tell this was the only British twin engined aircraft of that era to be fitted with fixed pitch props and later re-engined with P&W Wasps. The only photos I have been able to find aren't conclusive as, although the prop looks similar (side on view only), I can't be 100% sure if the pic shows a Wasp or Cheetah engined aircraft.
All other likely candidate airframes (US and UK) fitted with the Wasp engine always have VP or CS props. The Wasp is a powerful engine so it seems (to me anyway) quite unusual to find a fixed pitch wooden prop for the engine.
Perhaps it is a "maintenance" spare or similar to "get me home"?
Regards

Tony