HS Skins

Time: 4 Hours
Got a little work done in the Hangar today. Worked on deburring all the holes on both the left and right side HS skins. Then I treated the areas that will be dimpled with the Scotch-Brite pad. Next up was to use the DRDT-2 machine to dimple every hole in the shins, top and bottom. Tomorrow I will do some final Scotch-Brite work on all the pieces and maybe get some priming done.

Dimpling

Time: 3 Hours
Today I was able to get all the substructure of the HS dimpled. That’s the process of creating a dent around the hole so that a flat rivet will sit flush. The skins will have a dimple as well. The dimple creates a pimple of sorts on the underside of the metal. That pimple needs a place to sit in so that the two pieces sit flush with each other. So the substructure, like the flanges on the ribs, need a dimple to accept the pimple of the skin that will be mated to it. To do this process you use a set of dies, one female and one male, that shape the metal into the dimple.


For all the ribs and spars I used my pneumatic squeezer with the correct set of dies. This tool makes quick work of this job.


For really tights spots, like the nose of some ribs, I used a set of dies that uses a nail and the pull rivet tool.


Next up was the job of removing the blue protective plastic from the areas of the skins that have the holes so that I can dimple and eventually rivet them.


Next up will be deburring every hole, top, bottom, inside and out, on both skins. Once that is accomplished I will dimple the skins with my DRDT-2 machine. I set up the DRDT-2 and the table I made for it and clamped it to my workbench. It will be all ready for me tomorrow after all the deburring is done.

Right HS Skin

Time: 5 Hours
Yesterday I got in around 5 hours in the Hangar. First up was to tackle the dreaded HS-405, HS-702 & HS-404 junction drilling. I spoke about this earlier and how many builders end up with edge distance problems. Usually this distance is ok according to Van’s Aircraft tech support. I had to wait until my 12″ #30 and #40 drill bits got in at Grainger. Then I measured and marked the aft flange of HS-404 and drilled away. Those went very well drilling from forward to aft.

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I then used the same bits to drill from aft to forward on the two outer holes. These also included the HS-810, HS-814 stiffeners in the drill group. All in all I was happy with this task, thankfully I learned a lot from other builders mistakes.


Then I was off and running repeating everything I had just finished on the right half of the HS. <

Left HS Skin

Time: 4 Hours
I was able to build up the substructure for the left half of the HS. This included match drilling all the connections.


Next up was wrapping that structure with the skin. This includes a lot of Cleko’s. I’m sure glad I invested in a pneumatic Cleko gun. That tool saves a lot of time vs the hand pliers.


Next up was to insert the middle rib, HS-405 and the forward rib, HS-404. These are then marked so that you can drill them using the skin as a guide. This went fast and wasn’t too hard. However I may have an issue with edge distance on the forward upper and lower flange on HS-405. I will consult with the pros tomorrow and see what they think.


You can see the area I’m concerned about in this photo. It is the edge distance on the bottom and left to right (aft to forward).


Overall I’m happy with my progress today! Here is the results:

HS Ribs

Time: 8 Hours
Today I spent around 8 hours in the Hangar working on the HS. Items for today were to drill the forward flange of the middle rib, HS-405. I found that many builders have edge distance problems with this part of the build. The problem lies with the center two holes that you drill and how they match up with the forward rib, HS-404. The plans call for the measurements for all 4 holes which is fairly easy to understand. The errors occur when you match drill the aft flange of HS-404, that’s the flange that you trim so it clears the spar stiffeners. The issue is the remaining flange that you trimmed does not leave a lot of space for error when drilling. I decided to not drill the two center holes in question until I mate up the ribs with the spar and then drill from forward to aft ensuring that I make my edge distance. Seams like an easy option however that took me almost 3 hours of measuring, marking, consulting the plans and Internet, re measuring, marking and so on! So many builders end up with errors on this step I was really worried about doing the same.


Once I decided on my game plan I started by drilling the 2 outboard holes on the left and right middle ribs. The next step was to divide all the ribs into a left set and a right set. I did that and marked them as such. Now was the boring task if deburring, the process of removing the little edge on cut or drilled aluminum. You can do this with several different tools, my favorite is a Scotch-Brite wheel in my bench grinder. It is a very dense wheel of the same stuff as in you kitchen Scotch-Brite pads. This makes quick work deburring and scratch removal. A deburring bit is a cordless drill makes easy work of the drilled holes. Every hole needs this treatment on both sides! I then prepped all the surfaces with a Scotch-Brite pad to prepare them for priming.