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  • #16
    After posting the picture I realized that the quality is reduced when it was posted so it’s hard to see the extra hole.

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    • #17
      Originally posted by Dbahnson View Post
      .../...
      Hopefully PMdec will see this and offer an opinion. I get the feeling that it is an early and perhaps rare model.
      Hi,
      It is difficult for me to give an opinion:
      - the shape looks old, but
      - I don't know about the use of very thin copper/copper alloy to "shield" the blades before 1915,
      - the use of nails is specially strange (normally, screws and/or rivets),
      - the "D9 P7" marking is typically american for this era, so perhaps copper and nails were used there before WW1?
      - the stamping itself seems "industrial" (the digit are stamped one by one before WW1 and then are not very "straight").

      For me (and so "IMHO") it could be a prop made after (very after?) WW1 for exposition of a pre-war plane or engine. But I hope I am to be corrected...

      Regards,
      PM

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      • #18
        PM
        Thank you for your input. I looked at the propeller again after your reply and realized the nails are actually rivets. I assumed that they were nails when I first looked at them but after looking again I could see that it went through the wooden blade and came out the other side on each one. The metal on the propeller is brass and it looks like it was soldered along the seams. I have enclosed a couple of pictures. I’m sure seeing the propeller in person would help determine the age. Does anyone on the forum know where I could bring it in the New England area for someone to look at? I would just like to know if this is something worth keeping or if it is a reproduction disposing of. I appreciate everyone’s knowledge and helpfulness.
        Attached Files

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        • #19
          I doubt that it's a reproduction, but it may not be possible to identify it much further than we already have. There are a lot of possibilities.

          I live in Vermont and can look at it, although I'm not sure what else can be determined by doing so, but you never know.

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          • #20
            Hi,

            OK, if there are rivets, I change my mind: It was probably not made as a non-flying replica. But I doubt it is pre-WW1. Perhaps for use on a plane using an "old" engine or to fly an old plane in the early 20's.
            Anyway, I think it is better to keep it "as is": NO restoration or varnish in wait of more knowledge.
            BTW, I am sure Dave will be able to know more by direct view!

            Best regards,
            PM

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            • #21
              Originally posted by sanger22 View Post
              The center hole diameter is 2 inches.
              I'm not sure that measurement is correct. By looking at the photos the inch scribes of the ruler line up on the outside of the bevel, but the critical size is the shaft diameter, not where the rounding on the hole ends on the face.



              You would need calipers to accurately measure the inner diameter of the bore, but a rough alternative would be to cut a piece of paper 1 3/4 inches and see how it fits in the hole without bending or without leaving extra space.

              And although the diameter and pitch are in Imperial system measurements, the prop may have been designed for a metric built engine, and one would not expect to see different prop shaft diameters for any given engine, and it may be that the crankshaft diameter was the same for a variety of different horsepower engines by the same manufacturer.




              .
              Attached Files

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              • #22
                I completely understand and I appreciate everyones assistance. If you happen to run across any additional information I would love to hear it.
                Sincerely, John

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                • #23
                  Dave,
                  My apologies, I just noticed your post about measuring the hub correctly. I will do that and let you know. PM thank you for your thoughts also. I go to Vermont fairly often and would like to have Dave take a look someday.
                  Thanks again, John

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                  • #24
                    Dave,
                    The other side of the prop doesn’t have a bevel. I measured it from that side and it is almost exactly 2 inches. I have attached a photo.
                    Thanks John
                    Attached Files

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                    • #25
                      Originally posted by sanger22 View Post
                      Dave,
                      The other side of the prop doesn’t have a bevel. .../...
                      Hi,
                      If it may be of any help:The fact that there is a "non bevel" side of the central hole and this "non-bevel" is on the same side that the "flat side" of the blades shows it is a pusher. With the copper shielding it could (could!) be for a seaplane.

                      Regards,
                      PM

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                      • #26
                        PM,
                        Thank you, I am impressed with your knowledge. Why did seaplanes use metal sheathing on the blades vs wheeled aircraft?
                        Thanks John

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                        • #27
                          Does this change what you think about the possible age of the propeller? I apologies for all of the questions. Although I am ignorant in propellers I have been collecting antiques for a long time
                          Thanks John

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                          • #28
                            Hi,

                            On seaplanes, there is a very high risk the rotating propeller come in contact with water (directly the crest of a wave, or water "paquet" airlifted at takeoff).
                            But on pusher "landplanes" there is also a risk at takeoff from some dirt or stones propulsed by the wheels.
                            The difference (by the 20's: I don't know before) is that aluminium alloy is used on propeller of "landplanes" and copper alloy on seaplanes because salted water and aluminium don't mix very well!

                            Also, another remark: the prop is right handed and righthanded pushers are not common.

                            And no, it doesn't change what I am thinking about the age, even the contrary!

                            Regards,
                            PM

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                            • #29
                              I have two minor observations, neither of which will be new to regular forumites. I posted this observation about protecting props a few weeks ago.

                              During the course of WW1, various measures were introduced to protect wooden propellers. The RFC carried out tests in late 1912 and early 1913 into the effect of small arms fire and shrapnel on wooden propellers with the thought that perhaps wooden props should be armoured. The experiments showed that laminated wooden props could retain their integrity even if hit by several rounds, so the idea of armoured props was dropped.

                              Undercarriages had a degree of flexibility so three point landings were essential to prevent a prop tip hitting the ground. WW1 aircraft literally flew from unprepared fields which were far from smooth so propeller tips were sheathed in brass which gave some protection from slight contact with the ground, mole-hills etc.

                              Pusher aircraft such as the FE2b and the Vickers FB series had the engine mounted behind the pilot and the undercarriage so the propellers on this type of aircraft were subject to erosion from dust, sand, and similar detritus so brass sheathing was introduced on blade tips.

                              Aircraft fabric, Irish Linen, began to be used as another layer of protection against erosion and was first added to the propeller tips, then to the outer third of a blade, then two thirds and finally like your prop, to cover the entire blade.

                              Secondly, it is a flown example. There are slight creases on the brass sheathing which are caused by the wooden blade flexing. The blade was flexible enough to cope with this but the brass sheathing was not and has those characteristic slightly ridged creases.

                              With kind regards to everyone,

                              Bob
                              Last edited by Bob Gardner; 09-03-2019, 05:54 PM.
                              Bob Gardner
                              Author; WW1 British Propellers, WWI German Propellers
                              http://www.aeroclocks.com

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                              • #30
                                PM and Bob Thank you for your input. PM was brass also used on seaplanes or was only copper used for sheathing? So this prop was used on a pusher engine that was counter rotation?
                                Thanks John

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