1918 Flying Boat Prop Denmark

[Tue]

Hi all

I just purchased my first wooden prop dating back to 1918.
Supposebly it was usen on one of the Danish flying boats by the Danish army.

It has no decals but is sad to be manufactured by "Tøjhusværkstedet" of which I can find very little information, but prob. owned by the Danish army.

It has no reinforcements but it looks very similar to the props depicted on the flying boats, and also very similar to the picture of the prop mounten on the engine next to Ellerhammer.

If it is from a Danish flying boat there are only about 20 planes it could have come from, I would love to find out which one, but where to start?

I would very much appreciate any help on this.

First question, what does S 245 stand for?
Also, what should I do about the white paint splatter?

[Dave]

First, I'd just leave the paint splatter alone. It's just part of its history, and "restoring" it by removing the paint may lessen its value.

I think the "S" stands for "pitch" in whatever lanquage was used by the manufacturer. Typically, those numbers would be "diameter" and pitch, so if it is in fact 250 cm in length, which you can measure, then it's likely the pitch is 245 cm, meaning that in a theoretical sense it would move that distance in a single revolutioin, like a screw.

Finally, most of the propellers used on flying boats required metal sheathing to protect them. There are exceptions to that, but I would seriously also entertain that yours might have been used on land based aircraft.

It's a lovely looking prop, by the way.

[Tue]

Hi Dave, thanks for your quick replay.

I will leave the paint splatter alone, I thought about gently scraping it off.

The D def. stands for diameter as the prop is 250cm in lenght. If the P stands for pitch is it possible to say how powerful the motor would have been to propel it? Knowing the engine might make it easier to identify the plane.

You mention that it could be a land based aircraft. To explore that, I have attached a list of planes in percession by the Danish fleet. Most of them are flying boats though.

4 Maurice Farman 1913 - 1922
3 Henri Farman 1913 - 1919
1 Caudron 1914 - 1922
1 Bleriot 1915
2 Morane Saulnier 1915 - 1919
2 DK I & II 1916 - 1924
12 F.B. 5 1917 - 1924
6 Type Aa. 1917 - 1919
9 H.1 til H.5 1918 - 1924
2 Södertälje Werkstad 17 1918 - 1924
5 LuftVerkehrsGesellschaft B III 1920 - 1929
4 Brequet XIV. A2 1920 - 1927
5 Avro 504K 1921 - 1931
1 Rumpler BI 1921
1 Fokker D.VII 1922 - 1927
5 Fokker C I 1923 - 1933
8 Potez XV H2 1923 - 1928
2 Fokker S III 1924 - 1927





I will be happy to translate any info on the planes.

[Tue]

Found another great resource:

Looking at the props mounted on these planes, it looks mostly similar to the prop found on Glenten 1912-1913, but that is way to soon?

http://www.marineflyverforeningen.dk...r/flytyper.htm

[Dave]

I would first go to this page, then follow the link to the hub dimensions chart. That should at least tell you what engine it isn't likely from, but matching the dimensions doesn't necessarily mean that it's from that engine, as not all possible hub sizes are listed.

The fact that the pitch is apparently 245 cm with a diameter of 250 cm means that as pitch goes, it's fairly coarse, i.e. the blade has a high angle of attack. It's similar to having a transmission in a higher gear, where a flat pitch is equivalent to a lower gear.

When I get home I'll look through some known British and French propeller sizes and see if anything looks similar. In the meantime, if you can get the hub dimension match, it would help.

[Tue]

I am still waiting for the auction house to deliver my prop.

Going by your chart and the danish planes listed above, I can only find a match to the Gnome 100HK engine.

Which narrows it down to:

- OV's Flyvebåd F.B III, 1916-1924, 10 aircrafts made
Used for recon. built in Denmark

- Avro 504K L.B.I, 1921-1925, 9 aircrafts made
Used for training, built in the UK two of them were later modified in Denmark

Crossing fingers that the HUB matches the Gnome 100HK. I will meassure it as soon as it arrives.

[Tue]

Facts collected from this site:
http://www.ellehammersamling.dk/C82D...4C743EFA.W5Doc


It's says that Ellerhammer was trying to make a radial engine similar to the Gnome 80HK engine, but better as it would be lighter and require less maintanens. This might explain why the propeller on the Ellehammer engine looks the same as mine, the HUB is prob. identical to the Gnome engines.

In 1915 his engine was tested on the "Maagen" Flying boat.

In 1916 his new 6 cylinder engine was tested on land, on the same premesis as where the flying boats were constructed.

In 1918 Ellehammer advertised that his engine had succesfully carried one passenger in one of the Danish Navy's planes, and that the engine would sell for 18.000,- DKK.

It is possible that my prob. was simply used for test on engines, thus explaining why it has no reinforcements and that is possibly also fits the Gnome HUB.

Would be very exciting if Ellehammer had actually worked with this prob.

[Tue]

I don't mean to spam, this forum is just a great place to gather all the pieces. I hope it's alright?

I found this list of OV flying boats from the same area. Only one of them has a Gnome engine listed, which points to the OV flying boat number 5 or 12.

Pics found here:
http://www.ole-nikolajsen.com/navyflyingboatsfotos.htm

[Dave]

I don't mean to spam, this forum is just a great place to gather all the pieces. I hope it's alright?

It's fine. That isn't spam.

We've come to realize that the number of different designs and uses of propellers even prior to 1920 is huge - literally in the thousands - and that assembling the information into a usable database is a daunting task.

But we have to start somewhere....

[pmdec]

Hi,

The prop seems made of two different wood. In France, this was on use only after 1917, but I don't know about Danish army regulation. And 1918 15/6 may effectivly be a date if not drawing number.

On this time, it is astonishing that a float boat propeller was not shielded : they are on all pictures where prop is sufficiently visible.

Have you pictures of the other side of the hub ? Those of BR site are the same the ones you posted.

The prop seems a tractor one, as central bore on extrados is not flared (I am not sure of the right word).

Regards,
PM

[Tue]

Hi pmdec

Interesting fact about the french propellers. Thanks

The first two flying boats that the Danish Marine acquired in 1913 were french "Donnet-Leveque. A guy called H.P Christensen modified the two airplanes to make them more stabile, and later manufactured 8 flying boats of his own design but based on the French models. The new models were called F.B which stands for Flying boat bi-plan.

The planes were constructed at Orlogsværftet in Copenhagen, which he left in 1918, the same year my propeller was manufactured. So he was probably overseeing the construction

Source
Google Book

[Tue]

Note to myself

The original Mågen 21 "O.V.15, May 1917" was replaced by another Mågen 21 "O.V.21, July 1918". Other sources suggest that the 21 was renamed 22 after it was rebuild. The prop. is dated 1918 June 15th.

The F.B.IV engine
Mågen 21/22, 200 hp Curtiss

F.B.III engines
Mågen 4/14, 100 hp Curtiss
Mågen 5/12,100 hp Gnome Monosaupape
Mågen 6/11, 100 hp Mercedes

[pmdec]

Hi,

I hope you will post pictures of the other sides of the hub when you will get the prop !

Regards,
PM

[Tue]

If the weather is good, I will pick it up tomorrow morning. I will of course measure it and take lot's of pictures.

[Tue]

I got some new pics and measurements for you:




It comes close to the LeRhone 80HP on your data sheet, but the Center Bore and Bolt Circle is a little off?


pmdec>
"The prop seems a tractor one, as central bore on extrados is not flared (I am not sure of the right word)."

Could you elaborate on this?