A movable control surface attached to a vertical stabiliser, located at the rear of an aircraft and used, along with the ailerons, to turn the aircraft.
20-21Feb16
Another major part started and once again it seems I’m spending more time staring at the plans and scratching my head than actually building. But I think I’ve got it worked out now. So far I’ve got all the stiffeners trimmed to the right shape and deburred and the stiffeners for the left skin have been match drilled to the skin. Here’s a few pics of the work so far.
23-24feb16
More work on the stiffeners. All holes on the left side stiffeners and skin were deburred. The right side stiffeners were match drilled to the skin and then all holes deburred. Finally, all stiffeners and corresponding skin holes were dimpled. Here’s a pic of a stiffener being dimpled.
26feb16
A fun day scuffing, cleaning and priming all stiffeners and internal skins.
29feb16
All stiffeners were back riveted to the skins.
1mar16
Work on the rudder spar and all that parts that attach to it. At the bottom of the spar are these parts – in the pic below from L to R the R-904 bottom rib, R-902 rudder spar, the R-917 shim and the R-405PD rudder horn. The R-606PP reinforcing plate is at the top.
When all parts are drilled/match drilled and assembled they look like this – views from three directions.
At the top of the spar are the R-903 tip rib and the R-912 counterbalance rib. These are fluted then clecoed to the spar then the R-913 counterbalance skin is clecoed on and match drilled. Pics below.
The skins can now be clecoed to the spar and ribs and the R-916 rudder trailing edge can be clecoed in place.
3mar16
With the rudder assembled I drilled all the remaining holes to final size. I had missed one step when I was doing the counterbalance parts. It is mentioned in the drawings but no mention is made of it in the plans instructions. The pics below tell the story.
4mar16
The R-710 horn brace has to be trimmed to size before being fitted and match drilled. Pics below show the process.
The next step is to make the R-918 rudder bottom attach strips then clamp in place and drill. This is what it looks like clamped in place ready to drill.
One other job for today is to drill the E-614-020 counterweight to the R-912 counterbalance rib. The weight is then countersunk and the rib is dimpled -shown below.
5mar16
All the holes in all parts except the skin have to be deburred and dimpled. The narrow end of the bottom rib is very difficult to dimple as it’s not possible to get a dimple die between the flanges. I made a 3/32″ countersink in a piece of aluminium and rigged it up in the DRDT-2 as shown below. Then it’s just a matter of putting the male dimple die in the DRDT-2 and giving it a squeeze. It didn’t make brilliant dimples but they’re good enough.
Well, after I finished doing the dimples I figured out a slightly better setup by removing the bottom die mounting plate. Something to remember for next time.
Some of the dimpling can’t be done in the DRDT-2 so I just set up my squeezer in the vice which makes dimpling easier. Pics show the squeezer in the vice and all parts dimpled except for the skins.
6mar16
On to the skin where all holes are deburred and dimpled. I also countersunk all the holes in the R-916 trailing edge.
13mar16
A couple of hours spent scuffing, cleaning and priming all rudder parts.
14mar16
Plenty of riveting today. Reinforcement plates and platenuts were riveted to the spar. The bottom rib and all parts associated with the rudder horn were riveted together. The counterbalance rib was riveted to the spar and the counterbalance skin was riveted to the counterbalance rib. I then installed the counterweight and clecoed both skins to the spar and ribs. Some pics from today’s work.
15mar16
The rudder skin was riveted to the counterbalance skin and the tip rib was riveted to the spar.
16-18mar16
Did a little bit each day and riveted the skins to the spar and ribs. I then match drilled a straight edge to the rudder trailing edge.
19mar16
The R-916 rudder trailing edge wedge has to be bonded between the skin trailing edges. This is to help make sure that the trailing edge stays straight when riveting. I used JB Weld for the bonding material and I inserted a piece of dowel to hold the trailing edges apart for when I was ready to insert the wedge. It’s a bit of a messy job applying the JB Weld and I had to work reasonably quickly to get it on before it set so no pictures of that part of the process – but you can see the completed job.
21mar16
I wanted to make sure the JB Weld in the trailing edge was well and truly set so I figured I would do the leading edge before I riveted the trailing edge. I used a broomstick and a vise grip to roll the leading edges and that seemed to work fairly well but it still took me three hours to get the leading edge rolled and riveted.
I had been a bit apprehensive about getting the trailing edge right but I followed the instructions pretty much to the letter and everything turned out well. The trailing edge looks very straight and the rivets look good too.
And that would be the rudder pretty much finished.
Warbo's RV-7A 