Merits of Wooden Props on Late-War LW Aircraft?
 

Gentleman:

I have previously read about wooden propellors fitted to late war LW aircraft, such as the Fw 190D, without giving the matter too much thought -it struck me as a rational response to the shortage of strategic materials and the desirability of dispersing manufacturing to sites not reliant on the complex facilities needed to manufacture large metal components.

However, I noted in Caldwell and Muller's excellent The Luftwaffe Over Germany - Defense of the Reich the comment: '..The decline in manufacturing standards was strikingly evident. The Fw 190D currently displayed at the U.S. Air Force Museum has a wooden propellor.'

I read this as meaning that the use of wooden propellors necessarily represented a decline in aircraft quality, but I'm not clear whether the use of such propellors resulted in a decline in aircraft performance compared with metal propellors, a reduction in service life, increased vulnerability to damage, or other factors.

Clarification would be most welcome.

Thanks

Don W

Re: Merits of Wooden Props on Late-War LW Aircraft?
 

Hi Don,

I actually saw that USAF Museum Dora last week and also noted the wood prop (which was standard on the type).

Indeed the strategic materials explanation has a lot to do with it. But the Luftwaffe has used wooden props on earlier types as well (the Ju 88 and He 111) come to mind, so I am not sure if that's the full explanation. Perhaps they're also cheaper and quicker to produce?

I doubt service life would have been a big issue. Most aircraft probably didn't outlive their props in combat... ;)

Re: Merits of Wooden Props on Late-War LW Aircraft?
 

Wooden props are NOT a "decline in manufacturing standards". There are several advantages with wooden props.
FYI, the wooden prop on the USAFM FW-190D is the wrong prop. It's from a Ju-88, it's too big in diameter.

This may answer alot of your questions,

http://www.steenaero.com/Products/pr...rintFriendly=1

Regards,
Mike

Re: Merits of Wooden Props on Late-War LW Aircraft?
 

The Spitfire used wooden props. Would you say they also had a decline in a/c quality?

One thing about wooden props is if there was a ground strike it did less damage to the engine.

Re: Merits of Wooden Props on Late-War LW Aircraft?
 

Hello!

Metal vs. wooden propeller.

If a propeller of piston-engined plane has hit ground or some other obstacle the procedures after the incident are different depending of the propeller material:
- Engine with metal (usually aluminium) propeller automatically has to be taken apart and checked for damages (read expensive or very expensive).
- with wooden propeller the propeller torque plate (terminology?) is checked with measuring equipment. If the throw is within acceptable tolerances and other checks show no damage in motor then it is just new propeller and the "power-pack" is "good to go".

We have had that happening couple of times with a glider towing plane of our flying club. Nose gear has collapsed twice in very hard landings (several years between the incidents). Fortunately both times wooden propeller was installed and same engine could be kept. Major savings in money and time.

I do not know if this fact factored in the Luftwaffe thinking, however.


Cheers,
Kari

Re: Merits of Wooden Props on Late-War LW Aircraft?
 

The wooden props were wider and thicker, and so gave the a/c a greater rate of climb, but with a lower horizontal top speed.

Re: Merits of Wooden Props on Late-War LW Aircraft?
 

Gentlemen:

Thank you all for those most informative replies.

The overall picture you present is that there was no inherent failing in the LW's use of wooden propellors on aircraft such as the Fw 190D. In fact, considering the 190D specifically, the high climb rate associated with a wooden prop would have fitted nicely with its design role as a high altitude fighter.

It seems that the comment from Caldwell and Muller that the use of wooden props was an indicator of declining late war manufacturing standards may not be well based.

Regards

Don W

Re: Merits of Wooden Props on Late-War LW Aircraft?
 

Sometimes wood has inherent qualities that metal does not possesses (such as stretching tolerance)

Re: Merits of Wooden Props on Late-War LW Aircraft?
 

The Spitfire propellers were made from resin-impregnated wood, effectively a new material, not just carved from a piece of a tree in the traditional manner.

Re: Merits of Wooden Props on Late-War LW Aircraft?
 

IIRC German company Schwarz developed method to process wood at very high pressure and many propeller manufacturers bought the license; Rotol among them as well as Jumo.

Re: Merits of Wooden Props on Late-War LW Aircraft?
 

AFAIK For it's wooden propellers Rotol used German manufacturing technique called Leichtholtz-Mantel. Patented by Gustav Schwartz Propellerwerk already before the war.

At least in German propeller blades resin-impregnated (under high pressure) wood was used only on the middle, the sides being made of lighter wood strips (spruce IIRC) glued together and carved. This helped in keeping the balance of the blade, the "spar" in the middle being heavier than the leading and trailing parts.

Regards,
Kari

Re: Merits of Wooden Props on Late-War LW Aircraft?
 

One area of advantage I can think of is weight. I recall seeing somewhere comperative weights of 3 and four bladed props of light metal and wood, and the latter were relatively lighter.

... and saving just 50 kg can be equivalent of 50-100 HP in climb !

The downplay is, I guess, that wood is effected a lot more by wheater, dampness and so on. Perhaps more labourous to make, too.

Re: Merits of Wooden Props on Late-War LW Aircraft?
 

In a letter from Rolls-Royce to DeHavilland on 10th October 1942 the following was stated: "... the reduction in weight when using the wooden propeller was greater on the Merlin 61 Spitfire, than the mere difference in propeller weight, because ballast is required in the tail on this aircraft when a metal propeller is fitted. Because of this the total weight change was 150 lbs."

Re: Merits of Wooden Props on Late-War LW Aircraft?
 

The Sea Hurricane Mk.1 required the use of the DH metal propellor to balance the additional weight of the arrester gear.