19/08/2007 - Dimpling stiffeners & rudder skins

With all the stiffeners done and fitting well it was time to match drill the stiffeners to the skins and then dimple.

A couple of the usual suspects were involved in this process; one doing one side of the rudder and the other guy doing well ur the other side of the rudder.

So once they were done which was late in the afternoon; Bob and I loaded up his truck with all the bits I could let go.  This was most of the horizontal stabiliser, the vertical stabiliser and the rudder skins and stiffeners we had just made.  They are off to be primed.

Now I have done a lot of research on priming, spoken to a few people on priming, checked out my Reims Cessna and decided with the help of Bob on what we should do.
 

Strontium Chromate is Zinc Chromate's replacement.  Next step was for Bob to speak to AKZO Nobel in the UK and they confirmed that what we needed was

There are two different types of hardener for it; 92179 & 92217; the latter being faster drying.

On the spec sheet it states that Bombardier; Bae Systems; Airbus; and Embraer use this primer; so if its good enough for them its good enough for me.  AKZO Nobel stated it would give 25 years of protection; which is standard.

19/08/2007 - Assembling the rudder horn area

With a few hours left in the day we progressed into building the rudder horn area.  Using the uni bit was a bit scary as it chewed into a hole for a bolt but it seemed fine in the end. 

A shim had to be fabricated and put into place and the picture below shows the shim in place, between the rudder horn and the spar.

I also read a few builder's sites before taking on this section; and one stage of the fabrication calls for some flanges to be cut on the box section that reinforces the rudder horn.  The instructions state cut it off like you do for the stiffeners so the dimples and holes cut disappear; but a builder warned of minimum hole distance and to cut through the centre of the holes.  Once I had put it together I can see why as the flange of the horn rib is drilled through into the box section and there is not much edge clearance here.  Disaster averted.

Final picture of the day