Next to "Identification", the most common question asked about old wooden propellers relates to valuation. "What's it worth?"
In fact, there is always a range of "value" for any item, and it isn't even constant. Ultimately, of course, any item is only worth what someone else is willing to pay for it, not what someone claims it's "worth". So like everything from houses to stamps, the market determines a range of prices to expect. In the case of antique propellers, the market activity is not that broad, further making determination of value difficult and often inaccurate. Here is a very rough guide, based on my experience with collecting propellers over the past 40 years, to get a better idea of what I think they are worth.
Factors That Determine Value:
1. Rarity - a simple supply and demand formula dictates that items which are very difficult to find but are highly sought after will claim the highest prices. In the case of propellers, for instance, most of the propellers manufactured prior to WW1 were small in number and the vast majority of them ultimately destroyed in use or through neglect. WW1 saw a large production of propellers, but also a large consumption. Of those that survived the period, many were ruined through neglect or through well intentioned but foolish attempts to improve their appearance. Surprisingly fragile in their material properties many have just decayed over the ninety years since then. Aircraft and aircraft engine development, and in fact aviation in general, accelerated into the modern age, and propeller production and availability rose dramatically. So called "Modern" propellers were also considerably more durable and consequently have withstood the ravages of time much better and for a shorter period than the "Early" propellers. In addition, modern style wooden propellers could be replaced with metal propellers, leading many to become surplus of one sort or another. These factors all help dictate current values.
2. Identification and Provenance - Some propellers simply can not be identified as to their actual aircraft and/or engine usage. Others have clear and irrefutable characteristics which at best may identify the aircraft model for which they are intended. Beyond that, it is extremely rare to ever establish usage of a given prop with a specifc person or event, or even individual aircraft. I treat all claims to that effect as false, unless there is clear documentation of it, regardless of how sincere the person is in believing what grandpa said about it, and most of those claims can be shown to be implausible even at face value. Nonetheless, knowing what model aircraft a specific propeller was designed for has a significant positive effect on value.
3. Condition - this is a HUGE factor in determining value, and seems to be very typically overlooked by the casual owner. I'm always amazed how many questions I get asking for value without any indication of condition. Original condition carries the greatest weight, even if there are significant defects that have accumulated over time. "Damage" as such does not necessarily detract from value. A bullet hole from combat, a broken tip from a crash, even cutting a propeller then reassembling it to get it home from the war can actually add to its value. On the other hand, most efforts to improve appearances or alter use do significantly detract from value. This includes cutting the hub to install a clock or other device, removing finish, painting, etc. Actions that are taken to preserve existing condition (such careful application of wax) are acceptable methods that do not significantly affect value. Many propellers typically had manufacturer's decals applied at the time of production, especially with modern propellers. These are often an indication that original condition has been preserved. (Many of the early propellers did not have decals, however.)
4. Transportation - keep in mind that most early propellers are eight feet or more in length, and the surface is fragile, even though the construct itself is strong. This makes transportation without damage a challenge, so a buyer must factor into the value the costs associated with moving it to a new location. Those costs typically include travel to view the item, the cost of money transfer, crating costs including finding a reputable packer, shipping cost, and brokering cost with possible duty fees for any international shipping. Some larger propellers, and virtually all 4-bladed propellers, can easily exceed shipping company's maximum "dimensional weight" and can only be shipped via freight, even though their actual weight is small.
5. Economy - certainly this is less of a consideration than the factors listed above, but like any collectible "value" can fluctuate widely with world economic conditions, so past sales may not be a reflection of present or future value.