Kitfox Aircraft Stick and Rudder Stein Air Grove Aircraft TCW Technologies Dynon Avionics AeroLED MGL Avionics Leading Edge Airfoils Desser EarthX Batteries Garmin G3X Touch
Page 4 of 4 FirstFirst 1234
Results 31 to 36 of 36

Thread: Fitting Cowling

  1. #31
    Senior Member Cherrybark's Avatar
    Join Date
    Dec 2015
    Location
    Near Tyler, TX
    Posts
    509

    Default Re: Fitting Cowling

    Nut plates riveted to the convenient tabs on the frame and SS machine screws / nylon lock nuts along the arch of the firewall. I'm certain easy access to this area will be important down the road.

    John, your suggestion to use pop rivets on the firewall clecos worked nicely.
    Carl Strange
    Flying
    SS7, 912iS, Oratex, G3X

  2. #32
    Senior Member Flybyjim's Avatar
    Join Date
    Jul 2013
    Location
    Marysville, Pa.
    Posts
    585

    Default Re: Fitting Cowling

    I just got back the water pump housing from Kitfox, anyone know the torque value of the housing screws?

  3. #33
    Senior Member jrevens's Avatar
    Join Date
    Aug 2009
    Location
    Arvada, CO
    Posts
    2,146

    Default Re: Fitting Cowling

    Those are M6 screws. I believe that the Rotax recommended torque for 6 mm screws is 90 in. lbs. I know that this is the torque value listed for the bottom SS drain screw.
    John Evens
    Arvada, CO
    Kitfox SS7 N27JE
    EAA Lifetime
    Chap. 43 honorary Lifetime

  4. #34
    Senior Member Flybyjim's Avatar
    Join Date
    Jul 2013
    Location
    Marysville, Pa.
    Posts
    585

    Default Re: Fitting Cowling

    Thanks John.

  5. #35
    Senior Member HighWing's Avatar
    Join Date
    May 2009
    Location
    Goodyear, AZ
    Posts
    1,743

    Default Re: Fitting Cowling

    Piano Hinge - For those interested.

    I helped finish a Lancair IV a while ago and learned the technique from that build. This is the method I remember. For maximum strength at the joint it is suggested that the aluminum hinge be the extruded type rather than the rolled type. The closed hinge loops in the extruded type cannot be pulled apart.

    First, follow the manual to get the cowl sections centered and every other fitting procedure as recommended. Then with everything in position rivet top and bottom together through the joggle with soft aluminum flat head pull rivets (counter sunk). Begin at one end of the joint and proceed to the other to prevent “bubbles”. Rivet spacing suggested about 4 inches. This is[L1] done to maintain positioning for the next step that will enable a precise repositioning after the joggle on the lower cowl is removed and modified for the final assembly.

    Lay a strip of aluminum that spans the riveted joint so that holes can be drilled outside of the joggle area for the placement of clekos that will secure the top and bottom sections together in the established position. Again, work from one end to the other. Once drilled and clekoed, remove and mark the aluminum strips, for position. Drill out the aluminum rivets and separate upper and lower cowls. Cut off the joggle on the lower cowl and thin the glass there so it is similar in thickness to the top cowl. For the trimming I have used the diamond disk cut off wheels by Dremel. For the thinning I have used flap wheels.

    Once everything is prepped, re-fit top and bottom cowls together using the aluminum strips secured with clekos and fit the piano hinge. Verify positioning. Pre drilling the piano hinge will simplify final assembly. For strength and longitudinal smoothness, it might be wise to drill for solid rivets at the center of every hinge pivot extension. Fit, drill and cleko the hinge with the holes drilled (every other hinge hole) - through the aluminum strip also. (Using every other hole is to accommodate any possibility of a redo if alignment is not satisfactory. Remove all clekos to remove the aluminum strip and the hinges. Reposition the hinges and again, place the cowl top and bottom onto the airframe for a position evaluation. If everything is OK, remove, pull hinge pins and drill remaining holes. Mark each of the hinge halves for position identification. If there has been error introduced, the undrilled holes can be used to reposition as necessary.

    Counter sink the rivet holes at the outside surface keeping in mind that the rivet heads should be at the glass surface to help in preparation for final finishing. Apply a thin bead of structural epoxy between glass and hinge. Re-cleko the hinge halves temporarily (4 or 5 holes) for final positioning. Rivet the hinge in position using soft-aluminum solid rivets dipped in micro.

    A note on Micro. It is a very versatile filler. It can be mixed with epoxy to any consistency. From a runny glue to a stiff putty like consistency. Best here is a stiffness so that if drawn up to a peak in the mixing cup, the peak may bend over slightly, but not collapse.

    After final riveting, prepare all unused holes by lightly drilling with a counter sink to give a more angled edge to the holes and wipe a bit of micro into the holes. After curing sand everything smooth.

    Optional
    If, after final curing, the junction between top and bottom is not to your satisfaction, You might consider this next step. With the cowl mounted to the front of the fuselage sand the cowl surfaces adjacent to the joint to prep the surface. With a plastic squeegee (without a lot of pressure) squeegee a bit of micro into the hinge-line between top and bottom cowls and onto the adjoining surfaces as needed. Then using something like the rounded end of a table knife. Run the tip down the joint (knife 90 degrees to the surface) with the flat against the straightest of the two edges and the tip against the hinge. After curing, sand the joint and if necessary, add more micro to the surface areas and sand. With fiberglass aircraft – Lancair, Glasair, Varieze - this last “step” can become several steps depending of the level of perfection desired. Remove the hinge pins and separate the two sections. This can improve the surface flatness and gives a very nice thin joint line for final finishing and paint.

    A note on pictures: The second and third show a tab made from a bit of retained joggle to keep the sharper angled forward edges in alignment. It was sanded smooth, wrapped in two layers of clear packing tape, waxed and coated with separator, then a layer of glass laid up over it on the inside of the cowl. The fourth and fifth show a metal tab bent and Hysoled to the forward door post to keep the aft portion of the cowl snug against the post. Model IVs tended to flair out there a bit. The first and sixth are self explanatory.

    [L1]
    Attached Images Attached Images
    Lowell Fitt
    Goodyear, AZ


    My You Tube Channel

  6. #36
    Senior Member Flybyjim's Avatar
    Join Date
    Jul 2013
    Location
    Marysville, Pa.
    Posts
    585

    Default Re: Fitting Cowling oil door

    I do not seem to have the 2-camlock receptacles #92000.000 or the winged stud # 92002.000 for the oil door. Has there been a change to use a different attachment such as the skytain camlocks used on the cowl top? If so I still do not have any with wing tops.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •