rand robinson
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The KR2S Project

Landing Gear


The landing gear brackets are made from 0.125" thick 4130N sheet and are based on the Diehl design.  They are slightly taller due to larger AS5048 main spar and will be mounted on the forward side of the spar as this KR2S is going to be a tail dragger.  I am undecided as to the gear legs construction at this stage so will cross that bridge as I get to it.
 
4130N chrome moly After looking at a number of similar bracket designs I marked out the bracket pieces with permanent marker being careful to allow the sheet to be cut with a guillotine.  The bracket height leaves enough room at the top and bottom for the 3/8" thick foam/carbon fiber leading edge to make solid contact with the main spar.  
drill landing gear All the holes are drilled prior to welding using plenty of RP7 as lubricant and coolant to protect the drill bit and make boring easier.  This 4130N is pretty hard stuff.
landing gear brackets The brackets are jigged up and the magnets hold the plates at right angles to the base.
tig welded brackets I have done a TIG welding introductory course and was happy with my results.  However, for every good weld I can make, I do two not so good ones.  My welding skill is not consistent enough which is why I had Simon do them.  The picture speaks for itself.
painted bracket I painted the brackets in a gloss white enamel and had to clamp this in place just to help me imagine what the KR will look like with landing gear.
kr1 bracket The left bracket is epoxied and bolted with AN4-27 bolts through the top and bottom spar caps.  Temporary legs are attached to the brackets and the fuselage is then set level.  The right hand bracket is positioned the same distance along the main spar as the left and then the electronic level is used to angle the the leg identically.
kr1 leg bracket It is a little hard to see in this photo but I have rounded off the bottom edge of the gear bracket to avoid the possibility of creating a stress point when the gear legs flex on landing.....especially the hard ones.
scotchply leg Here is one of the Diehl gear legs I will be using.  A big "thanks" to Riley Collins for these.  Riley has already done all the work on them including 2 layers of BID as per the Diehl instructions and fiberglassing a nylon tube for the brake line down the forward edge, behind a rounded fairing.  The aft edge has also been streamlined.
scotchply gear I had to re-drill holes in the brackets to line up with the ones already in the gear leg.  The leg is floxed in position and tightened up using AN4 bolts.  These nuts will be replaced with elastic stop nuts before the leading edge is added.