Saturday, March 7, 2015

Rivetting the right elevator stiffners - 3 hours



I called the same friend over that helped me the week before (Jason) to lend me a hand again. Bending the right skin is more difficult than the left. Again like last time we gently pulled back on the skins and I used scraps of oak wood on either side of the stiffener to help hold down the skin flat. I used a dab of RTV on the back 1"-1.5" of the stiffener as an adhesive to the trailing edge and then riveted away. Very pleased with the results. I was really worried about getting this part right, Its very much a two person job! 




Sunday, March 1, 2015

The rear VS spar (Again) and the Left Elevator Stiffners - 11 hours



I set up in the basement TV as soon as I woke up and set out riveting on the vertical stabilizer. Things went well. I had about 10 rivets after my first round that I wasn't happy with and decided to drill out and redo. The rivets punched out perfectly with my new tool. I ended up bucking 3 rivets located on the bottom hinge bracket due to the tight space.



 I then moved on to countersinking the E-615PP trim access reinforcement plate to accept the correct NAS1097AD3-3.5 rivets to secure the nutplates. I used the hand deburring tool and slowly worked at the countersinks. After a few turns the countersink was perfect for the reduced rivet head size. I then riveted the nutplates, and then riveted the trim servo mounting brackets on the access plate.

Later in the evening I called a friend over to lend me a hand. I dimpled the elevator skins and then set out to back rivet the stiffeners onto the left elevator skin. This process proved to be a bit tricky when trying to set the rivets at the back near the bend in the elevator skin. I managed to have a friend gently pull back the top part of the skin allowing me to place the rivet gun over the last rivet. I used scraps of oak wood on either side of the stiffener to help hold down the skin flat as it wants to arc up as the top skin is pulled back. 


I used a dab of RTV on the back 1"-1.5" of the stiffener as an adhesive to the trailing edge. 

Riveting and removing rivets

Well. I've learned quite a bit this last while about riveting and removing rivets. First off, of course practice makes perfect. Nuff said. I still haven't master setting perfect rivets, but I am getting better. My success rate for setting AN426AD rivets is excellent with the pneumatic squeezer. Its fairly easy to ensure that the dies are set nice and square to the rivet and the piece. Setting AN470AD rivets is a bit more challenging. It's not easy to ensure that you are square on the rivet which is THE key to a successful rivet set. Its amazing how easy it is to be slightly off and as a result the rivet will slide to the side or bend.


Another thing I've learned is the danger of cutting rivets. Be careful cutting rivets with the rivet cutter as it can leave a slight angle on the rivet....resulting in a poorly set rivet.


A friend of mine Mike showed my that he has great success with his hand squeezer since he can slowly squeeze the rivet and easily see if the rivet is starting to slide, which then allows him to adjust and control the setting. The beauty of it is that if the rivet starts to bend he can stop with very little or no risk of affecting the hole (as a set rivet will stretch the hole a bit).


One trick that I picked up on is to take a measurement of my adjustable set holder in my squeezer for a given rivet set. I've spent so much time trying to adjust and re-adjust the set holder it was just a waste. Now I have a rough reference of my initial set up so that when I did go to set a rivet, it is very close to setting the rivet to its proper setting. All that is needed is an extra 1/4 or 1/2 turn to set the rivet perfectly. This is a huge time saver.


When setting flush rivets, I have found that electrical tape works incredible. It stops the rivet gun from travelling and protects the aluminum. AND its cheap!!!

Drilling out rivets is absolutely inevitable. In fact, I drill out quite a few. So I have learned very quickly what works and what doesn't. The number one rule if learned is GO SLOW. The VAN's manual is spot on in its instructions for drilling out rivets. Again a trick that my friend mike showed me is to use a smaller drill bit on the manufactured head. Using your hand turn the drill by hand a few times before you press the trigger. This will help the bit stay on center. Then Go to the #30/#40 bit and start to drill slow. You will always have to drill, check, tilt the drill, and drill some more to ensure that you are keeping on center. Once you have snapped the manufactured head off. Now comes the fun.


Getting the rivet out of thin material is fairly easy. Often I can just use the punch in one hand, and support the backside the other hand, and just push the rivet out. (it comes out with a pop and be careful that your fingers don't get in the way when the punch goes through).
 The one situation which is more difficult is when you have that small little tab when a rib meets a spar. I've tried to push out the rivet and bent the tab. Getting it to sit flush again is difficult. Best scenario is to support the tab with a block of wood when pushing the rivet out. If the tab bends, then I have found using a dab of Dow 3145 RTV on the tab and then pressing and holding the tab back in place (till the RTV dries) works excellent.


Getting rivets out of thicker material is much more difficult. Sometimes, it works to use pliers to turn the rivet a bit and pull it out (be careful not to scratch the material....Electrical tape and gorilla tape work great for this).




The little homemade tool as described in my other post works great for punching out rivets.