Bending and drilling the FL-706B bracket - 3.5 hours

 Note: Again, as per my previous post, refer to my build tip at the end of this post for the sequence I recommend. After building this portion I would do the sequence differently to ensure a more precise fit.

Next step is to clean up the FL-706B bracket, bend it and then drilling the FL-706A bracket and then drilling that assembly to the flap structure.
 

First thing I did was to fit the FL-706A angle bracket to the FL-706B bracket and drill the holes.

I marked out the bend line on the FL-706B bracket and clamped it in a vice. The plans call for bending it 6.3 degrees!!  Well, its a bit tricky since the material is so thick, but I managed to get really close. After some check, fit, bend, check, fit, I made the pieces work.

Now..this is where things get tricky...This ended up not being the best sequence as now I had a tough time getting the hole for the future flap control rod bearing to align. On the first go round, the holes did not match up well. Fortunately when I swapped the FL-706A angle brackets the holes aligned extremely well. Whew...Dodged a bullet there.

Now that the assemblies where done, I clecoed them to the flap assembly and began to drill the holes into the FL- 703 spar and the FL-704 rib.  Everything went well, except it seems that my first hole for the second flap assembly ended up drilled incorrectly. I thought I had the fit sorted before I drilled....guess not. After re-fitting.. I was about 0.030" out on my hole. Shoot!


 So I have two options now. Order a new spar, and re-use the FL-706A bracket, or make a new FL-706A bracket and re-use the spar (back drill the incorrect hole to the new bracket). Well both options need new parts from Van's.

Build Tip - So in Hindsight. If I redid the flap assembly, I would change the sequence of the build to maximize opportunities for the best possible fit. Sequence is as follows.
Step 1 - After fitting the flap assembly, you start fabricating the FL-706A angle bracket, cut it to the 2 5/8" length, but DO NOT TRIM the 3/4" leg just yet.
Step 2 - Edge prep the FL-706B bracket, bend it to the required 6.3 degrees. Then cleco the bracket to the flap assembly using the hole for the future rod bearing for proper alignment just as the plans call for. 
Step 3 - Start fitting the FL-706A bracket to the FL-706B bracket and the flap assembly with clamps, but do not drill holes just yet. Make sure the bottom edge of FL-706B fits nicely with the skin. Once all looks great. begin to drill the holes for FL-706B into the FL-704 end rib. Cleco all holes. 
Step 4 - Now that the position of FL-706B is locked in. Trace the outline of the bracket onto the FL-706A angle bracket...it will be extremely close to the required 3/4" dimension mentioned in step 1 but will allow you to fine tune the fit so that it is perfect. 
Step 5 - Clamp the FL-706A/FL-706B together and ensure good fitment. Carefully remove assembly, and drill the remaining holes that attach FL-706A/FL-706B in a drill press. Cleco the two pieces together.
Step 6 - Reinstall the pieces on the flap assembly and drill remaining holes that attache FL-706A into the spar. 

In my opinion this sequence gives better opportunity for a precise fit than the sequence that I used for my build.

Right rib #2 and misc sealing - 7 hours

Nothing like the day after a big airplane EAA/Fly-in to peak your motivation.

I laid into finishing riveting Rib #2 (the final rib to have bucked rivets). Rib #2 went in fairly well, again same as every rib, I had the odd rivet slightly 'cant' to the side on my while riveting. Here is what it typically looks like. (look at the second rivet in from the left)



Now a closeup.

The same rivet cleaned up

Well this simply won't do for me. So these I have been drilling out and re-bucking. I cannot nail down for 100% certainty what is causing the rivets to cant. I figure its a bit of combination of a few factors;

1 - I have dimpled the holes with tank dies. This results in a slightly deeper dimple and a slightly larger rivet hole. Which in my opinion aids to increase the chance of the rivet moving around a bit in the dimple.

2- Proseal. It acts as both a lubricant and a sticky medium. No question that it lets the gun/bar slip more easily when things are gooey, but it also has a stickiness to it. I suspect that when there is proseal on the bar/rivet tail. There is enough there to just pull the tail to one side when you are setting up to buck that particular rivet.

So basically on average I have been drilling out and re-bucking about 4 rivets per rib. Perhaps this may be more than the average builder...but in the end I am pleased with the end product. Its about on par with my leading edge riveting were no proseal is used.

In the end what personally worked for me (or greatly improve my chances of success) was to always clean the bucking bar and gun between each rivet set. I really think that this helped in reducing the change of a tail being pulled on initial setup. The disadvantage is that this adds lots of work and time to the session. But...Time is one thing I have and I sleep much better when I feel I have done the job right.

So...While I am talking about what worked and what didn't. I should probably summarize my thoughts and processes so far for the tanks. First off....the big debate of does a person proseal and cleco 24 hours prior to riveting? or do you wet set the rib (i.e. rivet right away). Well personally I intended to celco 24-hours prior to setting rivets after reading about it all on the forums.

But after discussion with some local builders....I switched over to the wet set method. Primary due to the reasoning that it greatly reduced the chance of pillowing the skin when bucking the rivets the next day. Although I am curious if bucking would have been easier with the 24 hour method. (no question that it is the cleaner method)

The biggest issue at first was to figure out method of applying proseal. Darin had lent me his Semco gun and I was fully intent on using it. I chose to use Popsicle sticks for the first rib just to get a feel for what I am up against, no sense in dirtying up the Semco gun straight out of the gate.  My first rib set was a huge eye opener. More in the time it takes me personally to set/rivet a rib in. I was surprised how quickly the proseal was setting up (I was using the 2 hour stuff) . Coupled with the fact that I needed to drill out and re buck the rivets that were canted, I just could not see myself doing more than one rib an evening. Well that started to rule out the use of the Semco gun. I dunno...Maybe I should just have used it anyway and bought a bunch of the syringes??? Oh well. Popsicle sticks worked despite it being messy. In the end I found that about 40 grams of proseal per rib did the trick.

I know this....I will be glad when I am done with proseal. It's not the worse thing, but I can't say I love it.

Well in any case. I set up to put the fuel markers on the inside of the right rib #7.


Almost to the end of the quart of proseal...I mixed up what was left and put a dollop of sealant on each rivet head of the right tank. A tedious process. No question the Semco gun would be a perfect fit for this task.

1 quart of proseal....gone. Need to order another. 

Thinking day!

It's amazing how after a couple days, your mess up seems quite a bit less then what you thought at the time it happened! I looked at it yesterday morning and thought....it's not so bad. It should be fine.

I showed some guys at the EAA meeting last night about my conundrum and to my delight, each person had a warm smile. It's those moments that you learn....You learn a lot. First it tells you that everyone in that room has been there. It's a welcome to the club smile! Secondly - It's a smile that tells you 'Hey no worries, there's always a fix'. I tell you I felt like a million bucks after the EAA meeting. I've learned that's why you need to go to them.

Today I received an email from Sterling @ Van's giving his sage advice. Short and sweet - Upsize to AN4 and build on. The relief that I hadn't totally messed up was a bit short lived as I began to think my next move. First....order AN4 bolts, washers, and nutplates. Oh...which nutplate. I knew that K1000-4 was not going to work with the spacer. So now I have to think maybe a one lug, or a compact nutplate. Then...that led me to questioning edge distance on the parts. Oh man.
I should really figure out if edge distances play a factor on these parts.

Update: Called Vans to determine if edge distance was an issue. In short, they didn't think so but their answer was not definitive. It was a bit frustrating as the fella on the phone said I could leave the AN3 bolt with the slightly oblong hole. (But I have already drilled it out to AN4). Later in discussions with my friend who is an airplane mechanic would explain that edge distances are more critical with rivets than bolts due to the loads incurred when the are squeezed/bucked while bolts do not exert the same kind of pressures on the hole. He said that due to the nature of the part in tension that upsize to AN4 is alright for what I have done.




Build Tip - I've learned this so far. Think twice, act once. If you think once you will act 10 times more (worry yourself, and bug everyone around you). It's funny....I've not really messed up the hard parts (bending skins, bending tabs, double riveting the rudder trailing edge). I've just really messed up on the easy stuff. It's all because I've researched and thought about the tough stuff but paid no attention to the easy stuff. That's when it bites you.

Note to self - Remainder of build drill everything thicker than sheet aluminum in a drill press, or make a poor man's drill guide. That would have really saved my butt on this one.

Completed riveting VS #2 - Started HS #2 - 7 hours

I riveted on the VS skin. It went extremely well. Using electrical tape to hold rivets while bucking works extremely well. The VS is ready for inspection. 

I then moved on to the HS. I drew out the HS layout in AutoCAD then printed it full scale, cut the template out and taped it to the part. The result was great. This saved me a considerable amount of time and the placement of lines and holes was surgical. Just like the lessons learned on the first HS. I tried to drill and match drill as much of the holes in the drill press. Results were impressive! 

Trim tab near complete - 3.5 hours

Probably the most time that I've spent messing around with one little piece. It took a whole lot of head scratching to figure out how to dimple some of the holes in the trim tab. I was a bit concerned that I was not going to be able to dimple the control horn without the dimple dies interfering with the side. It looks awfully close. I still have the other set of control horns from the kit (I used the second set that came with the electric trim) and I test dimpled those. Perfect! No interference from the dimple dies. So I dimpled the control horns.I was a bit concerned about the edge distance on the last hole as I trimmed it a bit for a flush fit with the trim tab...it checked out alright.

 

The last hole that needed to be done was the aft most control horn hole. It is extremely tight to the tab.

Nothing I could think of would fit. The tight space dimple dies I have won't fit. I was set on the fact that I may have to grind down one of my dimple dies. I asked a friend for help too.

I read on the vans airforce forum about a suggestion to make your own dimple die by drilling a hole and then countersinking the hole. That got me thinking.... I thought about using the oak block that I had from bending the tabs. What if I stuck the block back in, drilled the #40 hole, and then countersunk the block.  Well I did just that! Then using the rivet gun with the die holder rivet set, I set the pressure on low and gave it a couple shots. bingo it worked. Not the sharpest dimple but completely acceptable.

Then I set out riveting the trim tab. Probably one of the most tedious and frustrating riveting sessions. Had to be a contortionist with the squeezer and constantly change yokes and flat dies to get the right fit. Ended up drilling out about 8 rivets all together. Very difficult to get the AD3-3.5 rivets to set straight with all that going on with the trim tab. I needed 8 hands holding things. Ended up having to install a oops rivet in the aft most hole of the control horn. Just too darn tricky to get one to set proper in that hole. (Did I mention that I am becoming a master at drilling out rivets!)

Getting good at setting AD4 rivets...AD3 rivets are a bit more challenging. Seems they are easier to slump to one side.

Hitting the elevator wall - 1 hour

I cleco'd the E-703/704 assembly to the E-702 spar and quickly found out that I could not get the squeezer in to set the AD4-4 rivets. There was just no way, and it didn't matter what yoke I used. So, the only way to set the rivets was to then use a bucking bar and a double offset rivet set. I set out to set the rivet and quickly bent the rivet. I drilled it out and tried again. nope...strike two. I decided to leave it and try to set the bottom one. Strike three. I made a bit of a mess of the holes. I was now fairly annoyed with what I had done. I went inside the house to reassess what I was doing. After an hour break, I came back and tried again on the other elevator. Going very slow I began to set the rivet. It set fairly nice, and then my rivet set slipped off the head and put a nice smiley face on the manufactured head. Crap. So I decided to try to set the bottom one. Again going slow I began to set it when the gun slipped off the head and really did a number. Double crap. I decided I was done for the day and put everything down.

I came back later and assessed the damage. I'm certain that I could have drilled out the bad rivets and cleaned things up. I could have gone to an AD5 rivet and possibly saved the day. But I was just too worried that I might bend the rivet again and be in the same boat, just more defeated. I considered the fact that it has been a very long time since I had bucked rivets, and using a double offset rivet set by myself, was certainly not making things easier.

I then reasoned that if I started again with new 702/703/704 parts and adjusted the order of riveting, I could set all the needed rivets with the squeezer instead of bucking some of them. The best strategy at this point is to start again, but this time rivet E-702 and E-704 together first. Then I would rivet E-703 to E702/704. Another lesson learned!!!! I really need to think about the order of putting things together so to make sure I do it the best way from the beginning!

Preping Elevator Skeleton Parts - 1.5 hours

I deburred all the holes on the elevator skeleton pieces and then went to work with a light file on the edges of the pieces. I Finished the edges with the 3m wheel.

This process was shown to me by a friend and I think it works extremely well. Previously I was just cleaning/deburring edges with a 3m wheel, but there was always a slight bump where there was shear marks in the piece. Using a small light file over the edges then a light buff with the wheel produces excellent results.

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.

Building tools

A handy tip that I learned from one of the guys at the EAA meeting is to build some guides for both drilling operations and rivet removal operations. A little drill guide using a piece of round bar with either a #30, or #40 hole is a handy tool that ensures that when drilling a hole with a hand held drill, the drill bit is perpendicular to the piece. If you can have a tab welded to the side it will allow you to have a place to use a clamp on it.

A similar guide is great for using under a piece when you need to use a punch to remove a rivet.  The trick is to have a hole in the tool that is just slightly larger than the shop rivet head. If you ever need to punch the rivet out, the tool used would support the aluminum around the rivet and is helps you avoid bending the aluminum while driving out a particularly stubborn rivet.

I had ordered a few round bar pieces last week. All were 2" long and I got some 1" diameter and some 1-1/2" diameter. In retrospect....the 2" length is just too long.

I think I will re-order some pieces that 1" long and get some 1" dia, and 1-1/4" diameter. and use those as my drill guides. (Update....This is an excellent size 1" diameter and 1" long. Drill some on center, and some off to one side. The ones drilled off to the side come in handy for those tight areas)

I decided to use my 2" x 1-1/2"dia piece to make a guide for punching out AD4-X rivets. Driving these rivets out of the thick spar doublers has been a cause of much frustration for me. Hopefully this tool will safe grief for me in the future. I started out by marking center on a piece. I then set up the drill press and made a pilot hole with a small 1/16" bit.

 I then enlarged the hole with a 15/64" bit. Turns out that this hole size will allow removal of both a AD4-X and AD5-X rivet.

Time to get organized...More

I decided to take some time and get some organizing done. First thing I wanted to do is color code all my dies and tools according to size. I notice that often I waste time double checking sizes, and I dread the day that I use the wrong size on an important part. I raided my wife and daughters nail polish and went to work. I then made an excel spread sheet to list the colors to the sizes as a quick reference.

I finally won one!! Rear HS Spar - 4 Hours

I really thought about the project today while I was at work. It seems such a shame that I want to throw in the towel so early. It bothered me to give up. I reasoned that I was only going to get better if I kept with it. I decided to at least take another crack at riveting the horizontal stabilizer spar.

With the lessons learned from the other day, I was careful to check all the rivet call outs on the plans. And of course....they were slightly off.  For example the plans call for HS-609PP to be riveted to HS-603PP with 4-6 rivets.

Well 4-6 rivets are too short according to the gauge.

So I used 4-7 rivets and according to the gauge they were just a hair over....but darn near perfect. So I used those rivets instead. I ended up drilling out every tenth rivet or so and re-doing it as it is difficult to get the rivets set perfectly with the squeezer. I would set a few good ones, and then there would be one that was shifted to the side. (Very obvious if you looked down along the row of shop heads). I seemed to work out my technique for taking out rivets. As usual drilling the machine head is difficult as the drill still wants to wander off center when using the hand drill, but I could always seem to direct the drill head towards center. Using the punch I would break off the head.

Builders Tip -  But the trick I learned was to use big pliers (with electrical tape on the nose to protect the piece) and slowly twist the rivet at the shop head. This became extremely effective to remove rivets. (At first I put tape on the piece, but later found tape on the pliers worked better) 

And after careful work....I finally completed the HS rear spar!!! Yahoo!!!