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40% Ka-3 part scratch part kit

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  • #61
    Your craftmanship is second to none, a joy to study, just wondering have you created an unmix program for the stick so that a rudder input doesnt move the stick if you are Y leading from the normal servo out puts to the function?

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    • #62
      Alexis,
      The stick servos are plugged into separate receiver channels. The input for these channels are only the aileron and elevator stick control. There is no rudder interface input in this configuration.

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      • #63
        The instrument panel detail is progressing slowly. I did take inspiration from a Scale Instrument post in RC Groups back in April 2010 by Dean Gradwell. The instrument can and flange does lend a lot to the overall detail.
        2 Photos

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        • #64
          A little more work is required on the instrument panel but it's time to clean off the bench and get back to the airframe.
          1 Photo

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          • #65
            Started working on the elevators and hinging the other day. Finished up this morning making the pivot rod guide channels. Now to work on the hinge supports for the stabs and figure out a zero play drive system.
            The large Robart hinges were separated by grinding off the end off the pivot pin. They were then glued as a set using a 1/16th dia music wire thru all with the wire flush to the elevator spar. With the radius plates installed a check of the pivot rod was required to check and adjust alignment. Once the radius plates are caped that is no getting to the pivot rod. Pivot rod guides were placed on each side to guide the pivot pin into the next hing.
            5 Photos

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            • #66
              That's very neat Gene.
              Gunny
              Aviation Concepts rc

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              • #67
                Thanks Gunny 11,
                Worked on the hinge supports for the stabilizer side of the tail. The plans show no support for the hinge aft of the spar. This was just not acceptable in my mind so changes were made. Vertical grain blocks were glued to the stabilizer spar supporting the hinge to near the pivot location. Spacers (64th ply) were placed on each side to center the 3/16 wide blocks between the radius plates of the elevator. When final assembly is made the hinge will be epoxy flush on both sides to the support blocks. At least that is the concept so far.
                Supported by 1/64th ply spacers the hinge support blocks a left to cure. with a separation block between the stabilizer and elevator spars all three hinges support blocks could be set at one time. With the spacers removed the clearance is now set.
                5 Photos

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                • #68
                  Using the Ammonia method, for the first time, to soften the balsa wood worked out great. To keep it uniform the 1/16th balsa sheet was taped over a 1.25" dia rod to dry. It was then just a matter of cutting it to length, trimming and gluing in place. When the glue cured the hinge slots were trimmed flush to the radius plates. The elevator hinge pin also incorporates the drive link pin as a single unit. This way there is only one pin to misplace and being such an odd shape is unlikely.
                  The leading radius of the elevators need to be sanded to profile before the 2mm balsa sheeting is applied using the Ammonia method once more. The drive link pivot plates can then be fitted and epoxy in place. At least that's the plan.
                  After wiping the balsa sheet with ammonia it was tapped over a 1.25" dia rod to dry. The hinge pin unit also incorporates the drive link pin.
                  6 Photos
                  Last edited by Gene C; 07-19-2018, 04:19 AM.

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                  • #69
                    Some help required!

                    With the elevators slotted for travel, what is enough? I know that the total travel is max elevator + max rudder. The elevator chord from the pivot pin is 7.5 " so just how much travel is required on such a large control surface. At present with the current slotting there is 2.25" up and 1.875" down at the trailing edge. Not a hint in the manual, even in German and the plans show zip.
                    Thanks for any help,
                    Gene
                    1 Photo

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                    • ARUP
                      #69.1
                      ARUP commented
                      07-22-2018, 09:13 PM
                      Editing a comment
                      Anecdotal at best but since many model manufacturers recommend as much rudder throw as clearance allows check how many degrees of rudder travel are in one of your cruciform tailed models.
                  • #70
                    Saw this Ka3? at the Southwest Soaring Museum in Moriarty New Mexico. It has a nice simple color scheme, but oddly no registration numbers are visible.
                    Chris
                    Small enough to mount on the wall for display
                    1 Photo

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                    • Gene C
                      #70.1
                      Gene C commented
                      07-24-2018, 04:19 PM
                      Editing a comment
                      Thanks for posting Chris but that color scheme would vanish at around 800ft with my current eyesight. Thinking of a red with translucent wing and elevators like the Grunau Baby.
                  • #71
                    Finished hinging the elevators and mounting the control plates the other day. The stabilizer hinge supports were filled with West Systems 105 epoxy and 401 filler then clamped with wax paper and plywood backing on each side. After the epoxy set up firm but not hard the backing was removed and the excess epoxy removed while the wax paper was still in place. After fully cured the wax paper was easily removed from the hinge supports.
                    Looking forward to mounting the servos and giving it a try, but that well have to wait at least a week until the servos to arrive.
                    When setting the control plates in epoxy a petroleum base coated control pivot wire was used to keep a tight fit. The wire was then easily removed after the epoxy set with a had drill to encourage it just a bit. I'm hoping this will be enough deflection when combined with the opposite direction of the other elevator. This shows the max up position.
                    5 Photos

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                    • #72
                      It's now time to turn my attention back to the fuselage while waiting on servos. The tow release, radio and release servo platforms were installed. The release servo is removable buy use of a plate mount system. The operational force is against a solid stop so only a #2 servo screw is required to keep it in place. All the fuselage doweling will get a thin coat of epoxy before the light Gray finish paint is applied.
                      Although not the specific purpose for machine parallels, but they did keep the two platforms level and flat while the epoxy cured. The release servo is mounted using a plate rail system. The operational force is against a solid stop so only a small screw is required to hold it in place. A test fit of the release and servo provide an assurance that things are going in the right direction.
                      5 Photos

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                      • #73
                        Nice Gene. I'm assuming the thin epoxy resin coating is to strengthen and stiffen the dowels?
                        Gunny
                        Aviation Concepts rc

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                        • Gene C
                          #73.1
                          Gene C commented
                          07-27-2018, 04:03 AM
                          Editing a comment
                          It also seals the doweling for the paint process to come.
                      • #74
                        I got up the courage the other day to route the skid groves for securing the fabric covering.
                        After a coat of epoxy was applied to all the fuselage doweling, a weight check was in order. Maybe casting the pilot figure in lead could add ballast.
                        Like a window screen the fabric will be glued in position and capped with a material not yet selected. Bare bones at present.
                        5 Photos

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                        • #75
                          It's a blocked start but the Ka-3 must have a pilot. The only one in 40% that might have worked, beside an Axel, did not have a removable head set. The vintage look of the pilot will not be anyone in particular but hopefully have European features, what ever they are. The starting base was cut out of 2 lb 4" thick blue foam.
                          There are several links to carving faces on line so why not at least give it a try.

                          3 Photos

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