Caproni Ca.33 propeller type?

[Vasek]

Hello,

Attached is a photo of Caproni Ca.33, after a crash in Slovakia. General M. R. Stefanik died during this accident.

Would you be able to identify the propeller? What are the common propellers for Caproni Ca.33 (also marked Ca.3 or Ca.450), or the Caproni bombers from 1918-1919 in general?

The propeller on the photo seems to be different from propellers that are usually mounted on this aircraft, according to old photographs. It reminds me a German propeller manufacturer Axial Berlin, or its companies manufacturing these propellers under licence during the WW1.

Would you have any idea about a diameter or pitch of the propeller?

Thank you!

[pmdec]

Hi,

The 5 + 5 bolts on two different circle diameters could, perhaps, be a lead: seems a very special pattern.

Regards,
PM

[Vasek]

I am enclosing a photo of Caproni Ca.33 exhibited in Piešťany, Slovakia. The propellers are gift from baroness Caproni for the local Aviation Museum.

But it is apparently different propeller that the one from the crashed aircraft.

Maybe I shall wait for Mr. Gardner?

Thank you

Vasek

[pmdec]

Hi,

The propeller of your color picture has an "all on the same circle" standard 8 bolts pattern, and the shape of the prop is different from the one of the crashed Caproni.

It is possible that the crashed prop is the pusher, and then different of the tractive ones, but it seems very unlikely that the bolt pattern was different.

I have not HiRes publishable pictures of Grémont propeller serial FR (pusher) and FV (tractor) which were French built approved for 160 HP Isotta engines of the Caproni "450", but I can show a small composition (pic name tells all). FR and FV have the same diameter (2.72 m), different pitches (1.73 vs 1.57) and show a large hub, but with only 8 bolts, all on the same circle. It is impossible to tell from pics they are the same that the ones on the color pic, but the shapes are "compatible".

Could you post a HD pic of the crashed prop? Perhaps something could tell if it is the pusher or one of the tractor props (seems a tractor from RH, but some pics of a restored CA-36 show LH for the tractor ones (???).

Regards,
PM

[Vasek]

Hello, thank you for your interest.

I should explain the story. Mr. Stefanik (Slovak general and politics, who helped to create Czechoslovakia in 191, died in 1919 during a crash of Caproni Ca.33 near Bratislava. The crashed aircraft is captured in the photo I enclosed in the first post, but there is no better resolution, it's from 1919, unfortunately.

Several years ago, the Caproni was built for an Aviation museum in Slovakia. It represents the particular aircraft from 1919, but there are details, which don't really match with the original airplane. And some of those details can be the hub and propeller.

The propeller on the crashed Caproni is definitely a tractive prop.

Grémont propeller and 160hp Isotta engine were common on the Caproni "450"?

Thank you!

[pmdec]

Hi,

Thank you for the story.

I don't know if Grémont propellers were common on Caproni "450", but Grémont serial FR and serial FV are the only known approved serials for this a/c in France. It is a late "approbation": no approved serial in the French "papers" of late 1917. These two serial appear only in "American papers" which are, IMHO, from beginning of 1918 to 1919.

Perhaps the Grémont props were only used on French built Caproni: I have no knowledge about this. Perhaps some other brands were built later. Perhaps other serials of French propellers were exported: in this case, they had not to be approved and then don't appear in the military "papers".

Only one thing is certain: le prop on the 1919 pic has a very special bolt holes pattern and, if I have to do some research about this, I will look at pictures to find a 5 + 5 holes pattern. It seems to me it is the easier way...

Bob Gardner could have an idea: he knows very well the German props and some of them had "special" bolt hole pattern.
In France, from 1916, only 3 types of metallic hubs were approved ("A", "B" and "C", each with defined dimensions), and it seems that nobody went out those 3 before a 10 holes pattern (type ... "D", yes! with all the holes on the same circle) became approved in the 20's to use with high power engines (400 HP and more). After 1923, some other hubs (Q, R, S, T, W, each one with short or long "subcategory" appeared, but it is not relevant here.

Regards,
PM

[F.D.M]

I don't know how you come by this information but it is all wrong.

The aircraft wreck in your photo is not a Caproni and definately no Ca.33!
There are enough clues in the photo to be 100% sure.

First of all, the size of the wreck. The Ca.33 is a three engine bomber! This should ring a bell.
The bolt pattern you talk about is typical Austro-Hungarian and the visible engine is an Austro-Daimler.
Judging by the looks of the tail, the wreck is an Aviatik 'Berg' D.I or some derivative.
Besides the wreck, the soldier apears to be wearing an Austro-Hungarian uniform.

Hopefully, this will clarify some stuff.

Regards,

[Bob Gardner]

Quote; Maybe I shall wait for Mr. Gardner?

Sadly Mr Gardner knows nothing about Caproni aircraft, nor Italian propellers, and only a little about KuK aircraft and props.

The peculiar bolt arrangement is reminiscent of the unusual configuration used on props used on some large German aircraft (i.e. bombers) in 1917 and 1918, but in this photograph they appear to taper, so must be different.

In short, I can't help!

With kind regards,

Bob

[Bob Gardner]

Postscript: Research in the book Austro-Hungarian aircraft of WW1 by Peter Grosz et al shows an Aviatik D 1 made by Thöne u. Fiala which has a four bladed prop (two 2-bladed props bolted together) with this tapering configuration of bolts. This aircraft was fitted with the Daimler 200ps engine. Of the sixty D I made, only nine had the slightly less powerful Daimler 185ps, which the book suggests usually had a two-bladed prop.

Bob

[F.D.M]

The Aviatik 'Berg' D.I and derivatives were built by all the major Austro-Hungarian aircraft manufacturers. Approximately 700 have been built.
To my understanding the majority used two-bladed propellers.

A photo of the aircraft with the hub in question can be seen on Wikipedia.

https://en.wikipedia.org/wiki/Aviatik_(Berg)_D.I

Best regards,