LHD-12F
Thrust Duct

 


    Here's the thrust duct.  Well, not exactly.  This is the foam used to form the duct.  I fiberglassed one side (side facing down in this picture) and I'm beveling the other side.  Notice the arc.  With the bevel and the arc, the foam will wrap around the plywood inner duct without binding.  It's more understandable when you see the finished duct.

    The foam is nearly finished.  One side is beveled, and the lip radius has been sanded.  This piece is reading to be installed

    I'm gluing 4 pieces of 14" wide plywood to create the inner duct wall.

    2 - 48 1/4" (241/8" radius) disks were cut, and the plywood wrapped around them.  They're spaced with 6" long 2X4s.  The plywood is held to the disks with 3/4 wire nails.  The foam has been wrapped and is epoxied and Great Stuffed to the plywood.  I used ratchet straps to hold the foam tight to the form while the epoxy and foam cure.

    The inner lip radius has been rough sanded, and as soon as the duct cures, I'll sand the outer lip.  Before I install the duct, I'll glass both lips, along with the trailing edge.

    Looks pretty good, huh?  I checked the clearance with a piece of scrap wood 48" long.  Centered, I have 1/8" clearance!  Just right.

    It's now the 15th.  5 days left until the hoverin.  I'm without a prop, lift fan, sheaves, belts, and skirt.  A little nervous, yes.  The Rudders have been made, along with the lower mounts.  The upper mounts will go on shortly.  The dashboard is done, just needs gauges!  The duct is in place.  The disks will be kicked out after I install the engine cover with upper duct supports.

    A shot of the dashboard and duct with engine mount.
 

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