Announcement

Collapse
No announcement yet.

Wood or metal prop. Why not both?

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Wood or metal prop. Why not both?

    When I bought my L-2B in he summer of 1996 it came with a wooden prop. I flew it from Corona (nothing to do with the virus) california to my then home in Port Orchard Washington. I flew it up the central valley of california in July and got sunburned from all that sun shining through the skylight. I stopped in Merced to have lunch with a friend and we went through the airport dumpster and got some used pizza boxes and using my trusty leatherman we cut out some pieces to put into the ceiling to block out the burning sun on my neck. When I flew it to Alaska in 1999 it was a real challenge since the L-2 only holds 14 gallons of gas and I was loaded with an extra 5 gallon can strapped to the back seat with my sleeping bag,survival kit and the rest of my gear. Needless to say the performance was underwhelming. I decided to switch to a metal prop for a little better performance. Every little bit helps. When winter came along I put the L-2 on skis and went shopping for engine and wing covers. The lady making the covers asked me if I wanted a prop cover as well as an engine cover. I asked her why I would need that and she told me that you can loose as much as 20% of your heat through the propeller. I didn't think that was a big deal until the weather got cold and I noticed that my oil temperature gauge needle had not moved off the bottom (read cold) peg since late Semptember, no matter how long I flew. Having exposed cylinders (like a pre-war or an L-2) can make it really a challenge to get an engine warm in the winter. I plugged off the inlet at the nose bowl that directs cooling air to the oil tank and put a blanket on the tank without seeing any improvement in the temperature. I searched the internet for solutions but none came to hand. I didn't think that haphazardly plugging off the "eybrow" scoops with cardboard or duct tape would solve my problem. I read a posting by a long-time J-3 driver that the best thing to do is to just live with it.
    It then dawned on me, that big aluminun prop whirling around in the sub-zero weather must be acting like a big radiator just sucking the heat out of heart of the engine through the crankshaft. Great in the summer but not so goon in the winter. A wood prop on the other hand is a poor conductor of heat and at least helps keep some of the heat within the engine. With the winter air density and cooler outside temperature, the performance of the little A-65 is as good as summer performance with the metal prop. I purchased a second tapered shaft hub and mounted both props in order to make a quick change. The metal prop was mounted on it hub with the bolts torqued and safetied and the wood prop mounted ready to be torqued and safetied. When the skis went on the wood prop went on. When the wheels went on the metal prop went on. With a tapered shaft hub the change-over was relatively easy. The props are already indexed by the keyway and a special homemade socket on the end of one of those honking huge torque wrenches from Harbor Freight and voila, youre done.
    I have since replaced the A-65 with a C-90 which of course uses a flanged shaft so the switcheroo is no lonher that easy. One nice thing about the C-90 is that they are legal to use a wood prop. With the significant increased performance of the C-90, I have deciced that I will use a wood prop year round as summer heat where I live and fly is not a factor. It is smooth as silk not to mention cool looking.
    Now that I have captivated you with this saga, I bring you the sales pitch.
    The wood prop that I had on the A-65 is not certified for the C-90 and I would like to sell it. It is a Falcon/Fahlin 74-42 and I guessit has around 300 hours on it. It is in beautiful condition and has always been on a hangared airplane or stored in my climate controlled hangar. I would like to sell it as a QPC (quick prop change) complete with prop Yellow tagged tapered hub, crush plate and prop bolts. I also have an extra non-yellow tagged good condition tapered hub with prop bolts for a B-90 for sale. I am keeping the A-65 McCauley for now. You can PM me if you're interested in making an offer. I know that a new Sensenich wood prop alone goes for over $2500 so no lowball offers please.
    Bob Picard
    N48923 Taylorcraft L-2B
    N6346M Stinson 108-3
    Anchor Point, Alaska
    Bob Picard
    N48923 L-2B Skis/Wheels
    N6346M Stinson 108-3 Floats/Skis/Wheels
    Anchor Point, Alaska TF#254

  • #2
    Great write-up. I wish Catto or one of the others would get their composite props certified. Then you could have the best of both worlds.

    Comment


    • #3
      Never considered the thought about a metal prop acting as a radiator.

      Comment


      • #4
        Originally posted by Ragwing nut View Post
        Never considered the thought about a metal prop acting as a radiator.
        We had prop hub boots on the DC-6's for winter ops, or the props would sludge and freeze up.
        N29787
        '41 BC12-65

        Comment


        • #5
          Originally posted by Ragwing nut View Post
          Never considered the thought about a metal prop acting as a radiator.
          Yes, aluminum makes a great heat exchanger. That's why they make radiators out of it.

          Bob
          Bob Picard
          N48923 L-2B Skis/Wheels
          N6346M Stinson 108-3 Floats/Skis/Wheels
          Anchor Point, Alaska TF#254

          Comment


          • #6
            Originally posted by n6346m View Post

            Yes, aluminum makes a great heat exchanger. That's why they make radiators out of it.

            Bob
            I understand that, but didn't consider the prop being a heat sink and would move colder air.

            Comment


            • #7
              You guys be careful out there after you fly. Don't burn your hands.
              EO

              Comment

              Working...
              X