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1943 L2M on Floats

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  • #16
    Originally posted by PA1195 View Post
    But...if the power point presentation is available I'd review it and fill in the assumed verbiage. Gary
    If you want a copy send me a PM with your email. It won't let me upload it here.

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    • #17
      Thank you PM sent.

      Gary
      N36007 1941 BF12-65 STC'd as BC12D-4-85

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      • #18


        Originally posted by PA1195 View Post
        And as far as a L-2? on floats it would be interesting to read the particulars for basis of the one time float STC to A-746...and the later O-200's tests to maintain conformity when on floats. The under tail fin was determined to be required-why?-per CAR 4a? C-85 T's (BCS12D-85 and BCS12D-4-85) do away with that gadget on EDO 1320's.

        Gary
        I don't know if the ventral fin is really necessary but that's the way the FAA approved the STC, so on it goes. Remember, this was done a long time ago. As to the effect the O-200 has on the float installation, I believe that when applying for a subsequent STC or field approval, you must state somewhere that the new modification has no adverse effect on any previous modification. When I asked the FAA about using the data from this previous one time STC to apply for my own, they told me that most of the data would be considered and all I should really need is to redo the engine cooling tests since the original STC was approved for an A-65 engine installation and my airplane has a C-90.

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

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        • #19
          Tail fin would improve inflight stability if testing showed it was required...stuff like kick the rudder and return to stable flight soon or spin recovery within so many turns after so many cycles. Float flat side area forward of aircraft aerodynamic center can cause stability issues the rudder/stabilizer can't correct for as much. "Much" is a broad paint brush. It's described in CAR 4a under "Performance" 04.7 on. Cooling tests are a standard FAA task when mods are done that might affect same. I'd press for CAR 4a requirements only as applied during original certification under TCDS A-746 and not some Part 23 or whatever that followed years later.

          Again....Terry Bowden DER would be my first paid contact to start the process.

          Gary
          N36007 1941 BF12-65 STC'd as BC12D-4-85

          Comment


          • #20
            [QUOTE=PA1195;n187174]Tail fin would improve inflight stability if testing showed it was required...stuff like kick the rudder and return to stable flight soon or spin recovery within so many turns after so many cycles. Float flat side area forward of aircraft aerodynamic center can cause stability issues the rudder/stabilizer can't correct for as much. "Much" is a broad paint brush. It's described in CAR 4a under "Performance" 04.7 on. Cooling tests are a standard FAA task when mods are done that might affect same. I'd press for CAR 4a requirements only as applied during original certification under TCDS A-746 and not some Part 23 or whatever that followed years later.
            Originally posted by PA1195 View Post
            Again....Terry Bowden DER would be my first paid contact to start the process.

            Gary
            Gary,
            I had that discussion with Terry several years ago over lunch down in Waco. It would require a one-time STC and due to his limited knowledge of floats and the lack of float expertise at the San Antonio or Ft.Worth FSDO (not a lot of floatplanes in central Texas), It was decided that I would have a better chance of getting my approval up here at the Anchorage FSDO. As I mentioned before, they have already agreed to use some of the data from the one-time STC that I current own. I really don't want to start from scratch with a FSDO and DER 4100 miles and three time zones away.
            Bob Picard
            Bob Picard
            N48923 L-2B Skis/Wheels
            N6346M Stinson 108-3 Floats/Skis/Wheels
            Anchor Point, Alaska TF#254

            Comment


            • #21
              Thanks Bob for the info. Yes I guess that's not the best path. I'd still pursue a DER before the FAA FSDO. If it's time related and flying years are dwindling I'd not pursue the FSDO....unless Engineering in Juneau (who usually does the approving) has staff that had expertise relative to your project and components and you could speak with them prior to the submission of data. They'll push STC either one time or multiple and that's an expensive prolonged process.

              Maybe call EDO and see if someone there knows someone who does that kind of work and can be engaged? It'll still cost either time or money....which is more important to you?

              Back in the early '80's I took the data from a one time STC for Scout gear on a local 7GCB and was able within 6 months to turn it into a Field Approval for a 7GCBC. Same airframe on the 7GCB (tail's smaller) but a 7GCBC spring gear truss had been welded in to replace the old oleo setup. Spring gear was added and the 7GCB drop tested in Seattle after which a one time STC was approved. I had to prove like materials via prints and specs from Bellanca between the two aircraft then write up prints to show how to modify Scout gear (new inboard bolt hole and machined U-truss to hold at longeron). Later many have been converted but never a multi-STC as far as I know.

              Gary
              N36007 1941 BF12-65 STC'd as BC12D-4-85

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