German WW2 propellers

CJGibson

CJGibson

ACCESS: Top Secret
Senior Member
Joined
26 May 2011
Messages
2,111
Reaction score
2,694
I've been reading Eric Brown's "Wings of the Luftwaffe" and became curious about propellers.
By 1945 British and American aircraft were being fitted with four and five-bladed props, and in a couple of cases (XF-11 and MB-5), contraprops.

German high-performance types of similar vintage such as the Ta 152, Do 335 and He 219 had three-bladed props. Why the difference? The engines were of similar power, so were German props more efficient?

Chris
 
IIRC the Germans did make 4 bladed props but they never seem to have made it into service.
 
Damn, the man's got a point there. I can't think of a half-decent reason either, although it didn't seem to stop e.g. the FW190-D9 and Ta-152 achieving remarkable figures (and I seem to recall the Bf109K being credited with 450-odd MPH too).

I think I would add the Griffon Spitfire to those examples, Chris. Contraprops were at least being trialled in Spits before the end of the war, and the contraprop Spit made it into service (albeit afterwards) while the MB5 didn't...
 
If there's a serious quest for an answer to this I believe the Smithsonian Air and Space Museum could give a good answer. I don't have the email but it could be found on the net.
BIll Kohler
 
The Germans did build 4-bladed propellers for single-engined fighters (eg: the VS 19) albeit in small numbers. Most of their 4-bladed propeller designs showed up on bombers.

Increased engine power can be absorbed by increasing the number of blades while accepting increased complexity of the propeller hub. Or, individual blade widths can be increased with cost being a sturdier hub required.

I'm going to suggest that the Germans chose based on materials considerations. Making beefier three-blade propeller hubs cost very little in additional strategic materials. Wood was actually well-suited to making broad paddle blades and had little strategic value compared to the aluminum or steel required for many comparative Allied 4-bladed props.

Of course, there were also compressed-wood Allied 4-/5-bladed props such as Rotol's Jablo. In that case, Rotol first adopted the Jablo blades (made by F. Hills & Sons) as an alternative to the original metal blades as material shortages occured.
 
Thanks for that, particularly the point on materials. Ta 152H had wooden blades and possesed superb performance.

Four-bladed props were fitted to: Do 217M-1, He 177, Ju 288, 388 and 488 plus a variety of prototypes and paper planes (same was true of contraprops). Perhaps the gas turbine diverted development effort away from props?

I always understood that increased engine hp required more blades to convernt that to thrust, so five-blades and contraprops on high performance aircraft. Germans seem to have ignored that. I was informed by a bloke (who was building an ekranoplan in his shed) that three-bladed props were lighter and more efficient than four or five-bladed props.

Thanks

Chris
 
Increased power demanded some combination of:


wider blades
longer blades
more blades


Exactly which solution was taken depends on lots of factors. More blades is normally less efficient, not more - so if you can design a complex 3 bladed prop that does the job, its probably more efficient than a 4 bladed one. The 4 bladed prop is easier to design - its more of a "brute force" approach.


Perhaps the Germans stuck with 3 blades because they liked to use synchronized guns, and more blades would reduce firepower by increasing blanking intervals. Or maybe they were just being ultra-efficient.
 
Methinks it will be efficiency...

Interesting on the synched guns, that sounds plausible.

Thanks

Chris
 
Maybe props with a larger diameter (and lower revs/min ?) were preferred, if possible ?An example
could be the Blohm & Voss Bv 138C, which got 3-bladed props with broader blades for the outer engines,
but a 4-bladed prop for the middle engine (probably to reduce diameter) .
 
There was no magic foo-foo for either the German or the Allied engineers and part of this dicussion is based on limited knowledge. The use of three or 4 bladed propellers by the Germans was basically a matter of which trade-offs the engineers decided to use. The Ju 88 is a good example. Early prototypes used 3 bladed metal props (narrow chord). Stammwerk preproduction used 4 blade (narrow chord-both bomber and fighter versions). Early production used 3 blade metal (narrow chord). Second generation production went to 3 blade wooden wide chord, except for long range reconnaisance which retained narrow chord metal blades (perhaps this says something about efficiency of the narrow chord propellors at lower power settins to obtain maximum range). Later war production with further power increases continued with 3 blade wide chord wooden blades and there is a photo of a test Ju 88 with exceptionally wide chord wooden blades. The final production version Ju 88 night fighter was specified with 4 blade wide chord wooden propellers. So some of the trade-offs were power, efficiency, materials, tip clearances and mission profiles.

As an aside, note that in the USA, where in general the trend was to 4 blade propellors for higher power engines, the ultra long range B-36 had 3 bladed fairly broad chord propellers. Certaily not a casual decision, but almost certainly based on the engineering trade-offs.

Best Regards,

Artie Bob
 
Hi,

just to add to this discussion, the pressed wood technology the british used in their aircraft airscrews was bought before 1939 from the...germans :D ! It came from the firms Schwarz and Heine.

Junkers and VDM, the most famous manufacturers developed also 5 blade propellers, intended to be fitted to engines in the 2500 to 3000hp category (e.g. the Jumo 222), unfortunatelly not produced in quantity.

Contraprops (with 2x3 and 2x4 blades) were build by these firms for the 3500hp to 5000hp class, e.g. for the Argus As413, BMW803, DB613, Jumo222, 223 and 224. For example, the Junkers VS 23, meant for the BMW 803. Also VDM built a similar one for this impressive engine (I do not know what version of it).
Even the DB603 was to be equipped, in 1940, with a contraprop, developed by the Stoeckicht Büro, not proceed with.

The Jumo 225 was to field a eight(8) blade propeller, not contraprop.

If you consider turboprops, the germans planned diameter of up to 4,50m and 4,75m, e.g. for the amazing twinned Jumo 022 Z, depicted by me in another thread some time ago. The Stoeckicht Büro also developed a contraprop for the turboprop version of the BMW 028.
 
Wurger said:
The Jumo 225 was to field a eight(8) blade propeller, not contraprop.

If you consider turboprops, the germans planned diameter of up to 4,50m and 4,75m, e.g. for the amazing twinned Jumo 022 Z, depicted by me in another thread some time ago. The Stoeckicht Büro also developed a contraprop for the turboprop version of the BMW 028.
Click to expand...

Fascinating information Wurger. Do you have a reference for this by any chance? I'm not being picky, just interested.
 
This is a tad OT, but germane. Other than the very late mark Spits and Shackltons, were there any contraprop piston engined production aircraft?
 
Westland Wyvern, Fairey Gannet, Short Sturgeon

Tupolev Bear, Cleat and Moss, Antonov Cock

USA didn't field a contra-prop type, but a few prototypes.

Many thanks for the replies to this question, which is mere curiosity on my part, but I think we've all learned a lot.

Chris
 
USA didn't field a contra-prop type, but a few prototypes.

And the R3Y Tradewind. As I recall, a gearbox failure sent a contraprop into the fuselage of one example, resulting in it's loss.
 
CJGibson said:
Westland Wyvern, Fairey Gannet
Click to expand...

The original Wyvern, yes (RR Eagle IIRC), but most of the service models were turboprop powered, as was the Gannet (and the Gannet was in a league of its own with the Double Mamba).
 
As I understand it, it's not the total number of blades that are needed to convert increased horsepower into thrust, but the total area of the blades.

The Allies went with more blades, the Germans wider blades.


Chris
 
Some German samples
 

Attachments

  • Escanear0001.jpg
    Escanear0001.jpg
    75.9 KB · Views: 659
  • Escanear0002.jpg
    Escanear0002.jpg
    65.4 KB · Views: 675
  • Escanear0003.jpg
    Escanear0003.jpg
    381.8 KB · Views: 694
  • Escanear0004.jpg
    Escanear0004.jpg
    292 KB · Views: 661
  • Escanear0005.jpg
    Escanear0005.jpg
    167.2 KB · Views: 637
  • Escanear0006.jpg
    Escanear0006.jpg
    105 KB · Views: 292
Thanks Wurger - I have this book, though sadly as I don't read German my progress with it is slow. :-\
I understand most of the tables (I think!), but it is a big book. I will make a special effort to find the info on propellers.
 
The swept blades on the Dornier P.252 are also interesting, however I've seen very little about them.
 
Never noticed the propeller blades on the Dornier P.252/2 to be swept. Were the Germans working on scimitar-type blades in WW2? Btw, is there is info on the propeller profile and shape on the P.252/2? Thanks.
 
Regarding contra-props, personally I think that for single-engined installations the greatest improvement comes from the vastly improved handling. Just read the Spitfire test report comparing contra-prop and single-rotation variants, there is huge difference in handling. With the contra-rotating propeller especially directional trimming changes were reduced to near nil. And it also allowed the use of full-power on take-off. Look at the take-off performance of a restored Mk. XIX Spit retrofitted with a contra-prop.

Personally I find the synchronization theory a very plausible for German devotion to 3-bladers.
 
On the topic of wide-bladed propellers, note that P-47 climb rates improved when they added prop root cuffs.
 
A good book about the development of propellers.

Reinventing the Propeller: Aeronautical Specialty and the Triumph of the Modern Airplane (Cambridge Centennial of Flight): Jeremy R. Kinney: 9781107142862: Amazon.com: Books

Reinventing the Propeller: Aeronautical Specialty and the Triumph of the Modern Airplane (Cambridge Centennial of Flight) [Jeremy R. Kinney] on Amazon.com. *FREE* shipping on qualifying offers. An international community of specialists reinvented the propeller during the Aeronautical Revolution
www.amazon.com
 
edwest said:
A good book about the development of propellers.

Reinventing the Propeller: Aeronautical Specialty and the Triumph of the Modern Airplane (Cambridge Centennial of Flight): Jeremy R. Kinney: 9781107142862: Amazon.com: Books

Reinventing the Propeller: Aeronautical Specialty and the Triumph of the Modern Airplane (Cambridge Centennial of Flight) [Jeremy R. Kinney] on Amazon.com. *FREE* shipping on qualifying offers. An international community of specialists reinvented the propeller during the Aeronautical Revolution
www.amazon.com
Click to expand...
Ed, do you own a copy? If so, does it cover other German propeller manufacturers other than VDM?
 
Edwest wrote:

A good book about the development of propellers.
Click to expand...

I would say a "not so good book about the development of propellers". It shows a remarkable chauvinistic approach to this technology, centering it`s development in the US and neglecting european achievements. Per example, the Soviet Union`s work in this technology is completelly absent from this book.
German achievements are all about VDM which, while being a quite original and prolific technical enterprise (the book fails to show most of their novelties), wasn`t the only company doing research and production. Mr. Kinney suffers, I believe, from a sindrome affecting many english language authors that restrict their sources to british and US secundary documents (mainly post-war reports, always incomplete and very often biased) not using primary german ones. Lack of german language skills impairs their research heavily.
Where`s Junkers` developments in this book? This company went much farther then just buying in 1935 a Hamilton license (a two position variable-pitch propeller) with, just in 1943, the Vs 10, VS 11B, VS 13, VS 15, VS 21, VS 23, VS 27, respectivelly with 3,3, 5, 2x3, 2x4, 2x4 and 2x4 propeller blades, mostly made out of wood. What about the most actual scimitar-blades developed by A.W. Quick within the DVL (flown in a Me 109 between 1944/45, propellers made by the Heine-Propellerwerke), or even the AVA developments?
Argus and Junkers endeavours in propeller technique are mentioned in a bottom page note. The same goes to Messerschmitt, stated in a reference but not incorporated in the text (Messerschmitt had a most simple and effective propeller system, flown, e.g.,on the Me 109E).

As a proof of his pro-US bias, not even their allies go unharmed. The british unwillingness to shift from "woodenblader" aircraft to modern constant-speed propelled ones are well depicted, stating that only after that reverse the Spitfire became a fighter. It was with no surprise that their technical backwardness went even to trying to license-building VDM airscrews. German contribution to british propellers are mentioned too, in the fact that the Airscrew Company, as well as Jablo, relied on Schwarz and Heine compressed wood propeller blading. In this book, the brits were, on propellers, clearly the technological underdog, and in this I agree.
The author also explains that the US relied on mainstream technology to win the war, i.e. since we (US) do not master jet propulsion, a domain of the germans and british, let us "inflate" our propellers and propeller driven aircraft.

I`m Still waiting for a good book about the development of propellers! Soviet developments would be most welcome.
 
Messerschmitt also worked on reversible-pitch props to try and improve breaking distance. I've never heard of this being attempted by the US.

Also the aviation historian has a very good article on the Whirlwind that makes a strong case for the aircrafts high altitude issues being due to the props. It paints a rather unflattering picture of British prop development at that time.
 
Wurger said:
Edwest wrote:

A good book about the development of propellers.
Click to expand...

I would say a "not so good book about the development of propellers". It shows a remarkable chauvinistic approach to this technology, centering it`s development in the US and neglecting european achievements. Per example, the Soviet Union`s work in this technology is completelly absent from this book.
German achievements are all about VDM which, while being a quite original and prolific technical enterprise (the book fails to show most of their novelties), wasn`t the only company doing research and production. Mr. Kinney suffers, I believe, from a sindrome affecting many english language authors that restrict their sources to british and US secundary documents (mainly post-war reports, always incomplete and very often biased) not using primary german ones. Lack of german language skills impairs their research heavily.
Where`s Junkers` developments in this book? This company went much farther then just buying in 1935 a Hamilton license (a two position variable-pitch propeller) with, just in 1943, the Vs 10, VS 11B, VS 13, VS 15, VS 21, VS 23, VS 27, respectivelly with 3,3, 5, 2x3, 2x4, 2x4 and 2x4 propeller blades, mostly made out of wood. What about the most actual scimitar-blades developed by A.W. Quick within the DVL (flown in a Me 109 between 1944/45, propellers made by the Heine-Propellerwerke), or even the AVA developments?
Argus and Junkers endeavours in propeller technique are mentioned in a bottom page note. The same goes to Messerschmitt, stated in a reference but not incorporated in the text (Messerschmitt had a most simple and effective propeller system, flown, e.g.,on the Me 109E).

As a proof of his pro-US bias, not even their allies go unharmed. The british unwillingness to shift from "woodenblader" aircraft to modern constant-speed propelled ones are well depicted, stating that only after that reverse the Spitfire became a fighter. It was with no surprise that their technical backwardness went even to trying to license-building VDM airscrews. German contribution to british propellers are mentioned too, in the fact that the Airscrew Company, as well as Jablo, relied on Schwarz and Heine compressed wood propeller blading. In this book, the brits were, on propellers, clearly the technological underdog, and in this I agree.
The author also explains that the US relied on mainstream technology to win the war, i.e. since we (US) do not master jet propulsion, a domain of the germans and british, let us "inflate" our propellers and propeller driven aircraft.

I`m Still waiting for a good book about the development of propellers! Soviet developments would be most welcome.
Click to expand...


Is chauvenist the right word, or is it US-centric? The book was prepared for an English speaking audience and the common theme was 'we are the best.' The war movies I watched in the 1960s showed the Americans winning all of the time, with a bit of help from the British. When I asked my father, who fought for Poland at the start of the war, if that was what it was like, he said: "No son. It wasn't like that at all."

And good books about Russian developments? Getting books from Russia is difficult. Reading Cyrillic is difficult but I can read it once it is converted to Roman characters.
 
I also know that VDM was working on reversible-pitch braking props. On soviet airscrews, I recall some AV series props, some with paddle blades, flown with MiG high-altitude interceptors.
 
The Do 335 had a reversible pitch propeller for the front engine.
 
Germans had perfected the wood prop...why change something that works ?
 
sienar said:
Messerschmitt also worked on reversible-pitch props to try and improve breaking distance. I've never heard of this being attempted by the US.
Click to expand...

I have a couple of interesting documents on the early reverse pitch prop developments. One is a period English translation of a German document in which the author attempts to derive a basic empirical performance theory original dated 1944 (translated 45). And the second is a trial report from a Lancaster that was fitted with two experimental reverse pitch props (inboard engines) from Feb-April (I think)45. It clear from this that the trial development and prep have been ongoing for some time prior.

I’ve formed the impression that this was another example of a same problem, same solution simultaneously emerging from two independent inventors.... don’t know for sure.
 
Basil wrote:
In this overview Theodore von Karman mentions the German research in swept back propeller blades on pages 23 and 24
Click to expand...

Very sketchy, a bit more on the "Technical Intelligence Supplement" from Von Kárman`s "Towards New Horizons" reports. I am absolutelly persuaded that one should seek for primary sources, in this case german ones. Since 1943 the germans took at least 3 meetings of the "Entwicklungaussschusses Luftschrauben" or, for the ones who do not grasp or do not bother to learn german, "Development Committee on Aircraft propellers". Their propeller experts presented the results undertaken during those meetings, e.g. scimitar-bladind, both positive and negativelly curved, tests up to high-Mach numbers, laminar profile blading, "biplane" propellers, double blade propellers, shrouded propellers developed by Focke-Wulf (Pabst) and Dornier, counter(?)-rotating, contra-rotating, braking, suction profiles and supersonic propellers, among other technicalities. The document, written by DVL`s A.W. Quick, refers also a most interesting fighter-bomber project by Dornier, featuring 4 layouts (one of them with a tail shrouded propeller), which I have never heard of.
I must thank our dear master moderator, Jemiba, for helping me translating the most difficult and technical terms in this german report.
For the ones with an interest in german amazing technical developments in WW2, just send me a PM with your email and I will share the document.
 
As early as 1940 the Messerschmitt company was testing braking propellers in order to shorten landing runs. The same applies to propeller braking in dive bombing but, in this subject, heinkel was ahead with it`s He 118.
 

Similar threads

Back
Top Bottom