propeller ID help

[Hans023]

Can anybody help me identifying this propeller with:
- centre bore diameter 62 mm/25.4 = 2.44
- the 8 bolts hole diameter 10 mm/25.4 = 0,394
- bolt hole circle 108 mm/25.4 = 4.25
- weight 9 kg; wing span 250 cm

This is probably a Dutch propeller, but on what engine was it used? It was for more than 70 years within a Dutch pub (unfortunatelly too much sanded by former owner). That pub location was only 25 km away from Airport Rotterdam “Maasvlakte”, where “Koolhoven” was having his aeroplane factory; despite it looks a propeller dated from before that factory start (old stock from Koolhoven when he returned from UK?).

The propeller has on one side the burned in inscription of N 16.
On the other side most hamered in inscriptions are mostly unreadable: U / SP……40 / 80PK….LIN / ..D.30. The “LIN” suggests engine THULIN? Low HP at 80PK (was there a number in front of 80PK?).

I try to copy paste in later on... (2 photo’s of the too much sanded propeller).
Attached is a dirty propeller, of exactly the same model (unfortunately lost at auction Netherlands).

THANKS ! hansmooren@ziggo.com

[Dave]

That's going to be a hard one to know for sure. At the outset, I don't know of ANY of the commonly used early (WW1 era) engines that had a hub bolt hole diameter of 4.25 inches. See this chart. It's possible it's even older than that, as some of the early hubs were quite small.

[Hans023]

Thanks Dave!
Any tips where to start searching? (does the suggestion engine THULIN with Dutch aeroplane builder Koolhoven give an idea or email address of expert?)
Met vriendelijke groeten,
Hans

[pmdec]

Hi,
It is not possible to tell that two props are the same by picture only.
As usual, clear pics of the markings are the only way to identification, which can be impossible...
108 mm for bolt hole centers circle AND 62 mm central bore is very unusual.
PM

[Hans023]

As the prop is very wide/big and hammered with "80PK" (Dutch for 80HP), the application must? have been limited to low RPM rotary engines: Clerget 7Z; Le Rhône 9C; Thulin A ( licence Le Rhône 9C ); Gnome Lambda; Oberursel U.O ( licence Gnome Lambda ) - OR others TOO?
And the readable "LIN" hammered letters behind 80PK, suggests ThuLIN engine Rhône 9C (was this prop from Swedish aeroplane Thulin: the 9C engine on a Morane-Saulnier L - both licensed to produce there).

PM: as you are French could you trace the 3 key diameters for the Rhône 9C?
All other search tips welcome!
THANKS, Hans

PS Mr Koolhoven started in 1911 at Deperdussin (the prop was found 25 km from Koolhoven factory Netherlands)

[pmdec]

.../... PM: as you are French could you trace the 3 key diameters for the Rhône 9C?.../...

Hi Hans,

For French props, there is no key diameters for the 14-18 era. For 80 HP engines, you can find airworthy props from:
- 2.40 to 3.20 meters length
- 95 to 150 millimeters hub thickness
- central bore of 60 and 70 millimeters
- 10, 10.5 and 11 millimeter bolts
- 120 and 150 mm diameter of the circle on which bolt holes are drilled.

And many more possibilities for prewar era.

For 80 HP Le Rhône only, quite the same (for WW1 era):
- 2.40 to 2.90 meters length
- 100 to 150 millimeters hub thickness
- central bore of 60 and 70 millimeters
- 10, 10.5 and 11 bolts diameter
- 120 and 150 mm diameter of the circle on which bolt holes are drilled.

I know 80 different prop serials for 80HP engines, used on 41 a/c models.

So, you can't know about engine and aircraft by those measurements. ONLY the MARKINGS can tell something, and pictures of them are mandatory...

PM

[Hans023]

Wow, you are an expert PM.

The markings as noted fully on top are only readable after scanning the surface from 1.000 angles (photos show much less)...

I must conclude with you that the 108 mm diameter of the circle on which bolt holes are drilled, are a "show stopper" for searching in France. Despite that those named 80HP engines are France design.

I'm now thinking that such prop marked/made in the Netherlands ("80PK") must had a modified (Rhône 9C license) Swedish Thulin engine ("LIN") with 108 mm diameter of the circle on which bolt holes are drilled; period probably 1911-13. The name Thulin also pops up frequently in the earliest designed Dutch planes (tests w/o much succes).
But so far I did not much find about Thulin... (end of search?).

Any hints/tips welcome to proceed on pre war 80HP engines (would there have been more producers than: Clerget 7Z; Le Rhône 9C; Thulin A ( licence Le Rhône 9C ); Gnome Lambda; Oberursel U.O ( licence Gnome Lambda )?

THANKS,
Hans