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Botmite2
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repair - Botmite-1

Part One - Repair

  Nose view of Carbon Fiber plus Epoxy repair of fuselage landing gear.  Nose wheel collapsed toward rear shearing fiberglass shell while breaking vertical plywood wall pushing it down.

   Nose steering not shown :: plywood wall removed along with steering wire.
 

Part Two - Repair

  Underside view of Carbon Fiber wrap of Botmite-1 to strengthen fuselage body after fiberglass shell sheared from nose wheel slamming into curb.

   After 24 hour cure of Epoxy, CF sanding to make flush layers brought down uneven layers.  Loose fabric overlay was removed.

   Preliminary Result: shell now stiffer, much stronger with marginal weight increase.  More layers, sanding, reinforcement and finishing to follow.

Part Three - Cut open top cover over wheel support

   Area selected: Mark perimeter of top cylinder section over landing wheels and where wings have aluminum and carbon fiber rods which pass through fuselage. This section now cut using rotary cutting bit from top. Rear plywood truss cut through, front plywood remains in tact. 

     Note: plywood mount for screws which attach to the fuselage is broken across and parallel to aluminum wing braces.

Part Four - show plywood base

   Plywood base to be removed and replaced with new material.  Epoxy and carbon fiber to reinforce this housing to assure sufficient strength for 6 g turns and hard landings.

     Prior to epoxy work: obtain nitryl plastic gloves and industrial breathing mask with OV filters.  Ventilate air outside frequently.  Do not get liquid epoxy resin or hardner on your body. Also wear eye protection.

 

Part Five -  base CF coating

   Cut, paint epoxy under each layer of Carbon Fiber, repeat, trim each CF layer to fit perimeter and cut to glove fit difficult areas. Squegee excess epoxy.  Wrap entire CF work under aircraft bottom with 6 mil plastic, then duct tape tightly to airplane.

   Leave fresh Carbon Fiber plus epoxy to cure for 5 hours before removing temporary plastic wrap.  Make sure two part epoxy mix is thoroughly mixed prior to use for at least one minute of mixing.

Part Six - remove plastic wrap and prepare sanding 150, 220 grit

   Inspect now set Carbon Fiber epoxy bottom fuselage multilayer wrap. It should feel dry to the touch. 

     Machine sand 150 grit sandpaper to remove surface burrs, and smoothen shape being careful not to press into CF.  Focus on removing excess epoxy at this stage. Then change to 220 grit sandpaper to more closely coutour surface mounts for a smoother finish.

     Note: sanding carefully is a time consuming activity where light - like a small flourscent lamp - aids seeing the gradual swales and ridges across the fuselage. 

Part Seven - recoat epoxy

   After carefully sanding out small hills in the epoxy moving from medium 150 to fine 220 grit sandpaper. Then recoat the surface with a batch of 10 grams of epoxy. Wait 5 hours before touching the freshly epoxied surface.

Part Eight - sand, recoat epoxy

   With a mold this sand, recoat, sand ever finer, recoat is simply not necessary.  Also, with proper vacuum bagging and setup, this technique is not necessary.  Donít forget to tape the area you are not covering.  This will save you much time later on.

 

   Note using light after sanding with 330 sandpaper brings out the surface in contrast.  Steel wool over the 330 sanded area to begin to polish the epoxied area.

Part Nine - spray paint

     In a well ventilated area, coat fuselage a couple times in warm (mid 80F) below 50% humidity with spray paint. Cover LEDís with toothpaste before spraying paint and duct tape a straight edge around perimeter of sprayed area.

     At least 24 hours after spraying paint should pass before handling and working on aircraft.

Part Ten - make CF plywood sandwich

   Take 1/8 th inch plywood, epoxy carbon fiber twill 3k to both sided wrapped in 6 mil visqueen (plastic). After 24 hours, trim away excess material to shape steering support to replace broken plywood (shown lower left side).

       Use dremel cutting wheel to trim excess CF-plywood off. 

Repair 2

Part Eleven - Rebuild Steering Plate with
Carbon Fiber plywood sandwich

   Trim CF plywood piece to match perimeter of crashed plywood steering plate.  Match holes of plastic holder and plywood front plate using 1/16 th drill bit. After all holes align and cap screws thread exactly into sized and located holes, then epoxy plywood support with metal cap screw guides.

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