Gavin Magills Online KR2S Build Log


Hori Stab 1	Hori Stab 2	Vertical Stab	Rear Fuselage
Rear Fuselage
With the Horizontal Stabiliser frame complete it is time to build the mounting points for both the Horizontal Stabiliser and the Vertical Stabiliser in the rear fuselage. This consists of fitting the 'N' and 'O' frames to the fuselage and their ply webbings to support and secure the HS and VS. It also involves fitting the tailwheel support and the ply skins to the fuselage.
25th April 2011. First up I needed to mount the HS on the top longerons so I could mark the position of the front and rear spars of the HS. To do this I have re-arranged my workshop and moved the boat down from its storage rack in the ceiling and mounted it onto a couple of saw horses so I can access it more readily. The saw horses in the photo have since been replaced with a couple of new ones and the front one cut down so the fuselage sits level when I am working on it. In th ephoto I am checking to see the HS is sitting square on the fuselage. After the photo was taken I changed the point I was measuring from to the center of the firewall rather than the edge so I could get a common reference point for both sides as suggested in the plans.
With the HS square on the fuselage I was able to draw on the lines for the location of the 'N' and 'O' vertical supports.
5th - 10 May 2011. Over the last week I have cut and fit the various pieces of timber required for the 'N' vertical support. This is a photo I took after I had completed cutting and fitting the various parts. Note that I made a bit of a mistake in making the top gussets as these were not required. They would interfere with the front web if installed. Of course yours truly did not realise this until after I had finished glueing them into place which meant I then had to remove them after the fact. Not very clever really.
With all the components complete I glued them all in place. Note that I also fitted the rudder post at this time but have since removed it as I found the rudder post and doubler were not square on to the fuselage firewall. I didn't discover this till after I had glued the rudder post however.
14th - 15th May 2011. With the glue joints cleaned up I then drew up templates for the ply web's to support the front HS spar and after quite a bit of fiddling to get them to fit correctly this is the final result. They are not glued in as yet and will remain unglued till it is time to mount the VS and HS.
17th - 22nd May 2011. Moving on to the 'O' position web and the tailwheel mount, I cut and fit the tailwheel mount first.
Then made the 'O' position vertical supports. I had three goes at making these supports. Initially I tried just using lengths of 5/8" cedar but I wasn't happy with the result. Next I made a pair of supports connected by a cross member at the top and again I wasn't happy with the result. Finally I created the support as you see it here. This is made from a single piece of cedar and is shaped to fit between the top longerons and joins the two vertical supports as well. This gives a much more solid feel to the mount although it is somewhat heavier than just using verticals. As you can also see I initially made the support for the complete distance between top and bottom longerons. This enabled me to get the alignment of the sides very accurate. The lower sections will be removed once the web is in place.
With the 'O' position support glued in place I then cut out the 6mm ply web for the front of the support. I used the same method of creating a paper template first and then transfering it to the ply as I used on the 'N' position webs.
I then glued the 'O' position web to the support.
And this is the end result. Note that I have also added a cross member to the top of the 'N' position to add more support under the front HS spar. Fitting this cross member actually nearly caused me a bit of a problem as the rear web no longer fitted easily into place after the cross member had be glued into place. I had to use some soap as a lubricant and very careful bowing of the rear ply web to get it into place. It isn't coming out again thats for sure. There is enough room to get a glue brush in between the web and the spar but thats about it.
With the rear web fitted I could then remove the bottom part of the 'O' position support. Here I have marked out the part of the supports to be removed.
And after removing the bottom part of each support this is the end result. Gotta say I am pretty pleased with how it has come out. The rear fuselage will remain like this now till I have completed the Vertical Stabiliser at which time I will be cutting the holes in the 'N' position webs to secure the forward spar of the VS.
Sept 12th 2011. With the VS frame complete it is now time to fit it to the support webs in the rear of the fuselage. Initially I started by marking where I was going to cut on the web. It took a while to figure out how to do this. In the end I removed both webs and mounted and clamped the VS in place and used a ruler resting against the VS forward spar to mark the fuselage verticals. Then after removing the VS frame I refitted the webs and marked them up based on the lines drawn on the fuselage verticals.
Cutting the holes in the webs was a whole other mission. After initially trying a dremel tool with the webs in place, in the end I removed the webs and cut them on the scroll saw. I drilled small holes in each corner which allowed me to pass the scroll saw blade through web to remove the large plug of web. I then used a file to make the angle edges of the webs. Here is the forward web with the hole cut.
With the webs refitted and the VS fitted here is the result. Not bad.
I then cut out the triangle support block for between the web and the VS front spar.
And the support blocks for the front of the front spar.
With the HS and VS fitted this is how the rear fuse is looking at present.