Wooden Propellor

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Wooden Propellor

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  • #2495
    mick
    Participant
      @mick65121
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      #346093
      mick
      Participant
        @mick65121

        Does anyone know of a propeller manufacturer, or chap in a shed, who could make me a bespoke 28 x 10 prop? The problem I'm having with off the peg versions is the hub diameter and boss thickness as it needs to fit a WW1 rotary engine. I can supply a suitable piece of laminated walnut if required. Thanks.

        #346100
        Emgee
        Participant
          @emgee

          mick

          Is the prop for static demo or does it have to survive power runs ?

          Emgee

          #346110
          JasonB
          Moderator
            @jasonb

            Was that you asking over on MEM? if not there are some links in this thread

            #346119
            Speedy Builder5
            Participant
              @speedybuilder5

              Why have you chosen walnut ? I live down the road from RATIER who have been producing full sized propellors for more than 100 yrs and they have a museum. I haven't seen any walnut props there. Acacia/oak, mahogany and of course composites and Al alloys.

              #346123
              Neil Wyatt
              Moderator
                @neilwyatt

                The Walnut Propellor Company

                en.wikipedia.org/wiki/Hartzell_Propeller

                #346124
                Neil Wyatt
                Moderator
                  @neilwyatt

                  Useful article on wooden propellor construction here, suggests walnut may be better than mahogany. Certainly looks nicer

                  Neil

                  #346135
                  Trevor Crossman 1
                  Participant
                    @trevorcrossman1

                    Hello mick, if you want to make your own propellor it is not really too difficult, i speak as one who has done so in my former life as an aircraft inspector. Walnut and Maple is a very good combination to use, and much hard work is saved by cutting and glueing up the laminations in a staggered fashion rather than a rectangular bulk of timber. See if you can find a copy of the propellor making book by Fred Clutton, use our friend Google or enquire at the Light Aircraft Association for both the book and/or one off makers.

                    Trevor

                    #346139
                    Neil Lickfold
                    Participant
                      @neillickfold44316

                      Canadian Hard Maple is a very good choice for Wooden props as well. Find some with straight grained will make a great prop.

                      #346168
                      mick
                      Participant
                        @mick65121

                        Hi. Jason. Yes I am he, but for some reason that trail suddenly went cold, he did say that he had over three months work to get through till he might have a window. The prop is to fit a running engine. Thanks for the input.

                        #346172
                        Martin Kyte
                        Participant
                          @martinkyte99762

                          Beech if you want to save money.

                          Martin

                          #346183
                          Emgee
                          Participant
                            @emgee

                            Here's a link to one of a multitude of 28×10 wood props for sale, just an email or tel call will get the hub dimensions

                            **LINK**

                            Emgee

                            #346206
                            Roderick Jenkins
                            Participant
                              @roderickjenkins93242

                              Presumably Mick's prop needs a hub big enough to use several studs on a PCD rather than a single hole through the middle.

                              Regarding suitable woods; it is, perhaps, worth bearing in mind that American oak, walnut and maple are all different species with different properties to those grown in the UK. Similarly "mahogany" covers an enormous variety of similar looking but otherwise unrelated species – There are no EN numbers in the timber trade!

                              Cheers,

                              Rod

                              #346219
                              Trevor Crossman 1
                              Participant
                                @trevorcrossman1
                                Posted by Roderick Jenkins on 15/03/2018 12:15:30:

                                Presumably Mick's prop needs a hub big enough to use several studs on a PCD rather than a single hole through the middle.

                                Regarding suitable woods; it is, perhaps, worth bearing in mind that American oak, walnut and maple are all different species with different properties to those grown in the UK. Similarly "mahogany" covers an enormous variety of similar looking but otherwise unrelated species – There are no EN numbers in the timber trade!

                                Cheers,

                                Rod

                                Definitely agree, and although this prop is not going to propel a piloted aircraft, then the timber should still be selected with regard to grain slope, knots, pitch pockets, shakes and so on before the wood is laminated so as to be reasonably sure that the completed item stays together. The glue should be of a high standard standard, prefereably something like Aerodux or an epoxy and not any old pva or old bone glue as a 1/5 scale rotary will still be able to generate a respectable level power and torque. A disintegrating 28" prop would be rather dangerous.

                                Is your engine the Blackmore Bentley BR2 mick ?

                                Trevor

                                #346264
                                mick
                                Participant
                                  @mick65121

                                  Hi. Trevor. Its definitely a BR2, but of mixed parenthood!

                                  I've spent a couple of months trying to source a prop sympathetic to the original engine and to that end I have contacted numerous suppliers both here and overseas about the sizes of the boss, but the diameter and thickness of the boss was always too small, so I don't intend to compromise the appearance of the engine by using the wrong prop and so I need to find a chap in a shed that's prepared to make one.

                                  Edited By mick on 15/03/2018 17:44:46

                                  #346280
                                  Trevor Crossman 1
                                  Participant
                                    @trevorcrossman1

                                    mick ,

                                    p.m sent,

                                    Trevor

                                    #346282
                                    JasonB
                                    Moderator
                                      @jasonb

                                      Have you tried the props made for the big engines from 3W, they will take a 28×10 or more and have a multi bolt fixing much like the BR-2 on the smaller engines and the bigger ones that look like they use a knurled flange actually have a 63mm bolt PCD so should have a bigger hub than you need.

                                      #346284
                                      Grindstone Cowboy
                                      Participant
                                        @grindstonecowboy

                                        As an altenative to an epoxy, you could use one of the foaming PU glues e.g. Gorilla Glue – very strong when used properly.

                                        Rob

                                        #346319
                                        Ian S C
                                        Participant
                                          @iansc

                                          It might be worth looking at such sites as Midland Paramotors Ltd http://www.midlandparamotors.com/propellers/wooden/

                                          Ian S C

                                          #346326
                                          Trevor Crossman 1
                                          Participant
                                            @trevorcrossman1
                                            Posted by Rob Rimmer on 15/03/2018 20:16:52:

                                            As an altenative to an epoxy, you could use one of the foaming PU glues e.g. Gorilla Glue – very strong when used properly.

                                            Rob

                                            PU glues are indeed very strong adhesives when used correctly, but are certainly not suitable to use in the construction of a functioning propeller due to the fact that they are foaming adhesives and so the cured glue line is interspersed with micro bubbles. The constant and cyclic flexure and vibration of the prop blades when the engine is running and transmitting power would eventually lead to glue line failure and delamination and disintegration. Even model size props, and this is for quite a large scale engine generating considerable power, flex a lot when running

                                            They're quite okay just an ornamental prop though.

                                            Trevor

                                            #346362
                                            Howard Lewis
                                            Participant
                                              @howardlewis46836

                                              A friend who has designed and built a 7 cylinder radial engine, says that he sourced his prop from China.

                                              Howard

                                              #346383
                                              Gordon Tarling
                                              Participant
                                                @gordontarling37126

                                                There used to be a chap in Wales who would hand carve any prop you wanted, but I'm sorry to say that he's long gone now. It may well be worth contacting Menz in Germany, they were very accommodating when I needed a L/H 26 x 12 prop for my Tiger Moth. They made me two custom props and didn't print their brand logo on the props, to make it easier for me to finish them. Ask them, all they can say is 'no'.

                                                #346399
                                                Grindstone Cowboy
                                                Participant
                                                  @grindstonecowboy
                                                  Posted by Trevor Crossman 1 on 16/03/2018 09:54:56:

                                                  PU glues are indeed very strong adhesives when used correctly, but are certainly not suitable to use in the construction of a functioning propeller due to the fact that they are foaming adhesives and so the cured glue line is interspersed with micro bubbles. The constant and cyclic flexure and vibration of the prop blades when the engine is running and transmitting power would eventually lead to glue line failure and delamination and disintegration. Even model size props, and this is for quite a large scale engine generating considerable power, flex a lot when running

                                                  They're quite okay just an ornamental prop though.

                                                  Trevor

                                                  I never thought of that, thanks for the warning, Trevor.

                                                  Once again proving a little learning is a dangerous thing blush

                                                  Regards,

                                                  Rob

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