392 hours on the hobbs - The 3 D's are in progress

That's drilling, deburring, and dimpling the parts for the left elevator. It is amazing how much more progress you can make once you get past the stupid counterbalance drilling fiasco. In the days since my last post I managed to get the elevator skin and frame parts match drilled, and I am about to finish deburring, dimpling, and countersinking everything.

Here is the elevator all clecoed together adn ready to drill:

A note about the control horn. Apparently many folks have issues with the control horn holes not lining up in the E705 rib and E702 forward spar correctly, and they have to drill additional holes or try to fill in the others that end up a bit oversized. I am pleased to say that I had no such troubles. Everything lined up perfect.

Here is a bit of an oops on my part. Of course it happened because Van's did a lousy job of explaining everything that should be done BEFORE you rivet the E616PP trim tab reinforcement bracket to the bottom of the skin. I should have gone ahead and drilled, dimpled, and installed the nut plates that will hole the access panel for the trim tab servo in place. Now I have to get these holes dimpled somehow and figure out hoe to rivet the nut plates on. I think I will be using my C Frame tool for some of the dimpling/riveting where I cannot get to the holes with a squeezer.

Next - at least I won't have to drill out the rivets this time to drill out and dimple the elevator skin and counterbalance skin for the number 6 screws that I will use to attach the fiberglass tips to the elevators. Did it all ahead of time this time.

Next is another area where folks seem to mess up alot. IN this case the instructions from Van's are clear. This is a blurry pic of the rear elevator spar where the trim tab will be attached to the elevator. You must dimple the bottom flange of this spar and countersink the top flange. The countersink in the top flange is necessary so that the trim tab hinge can be installed flush up against the bottom of the spar flange without being dimpled itsef. You are making a kind of aluminum sandwich as it were, with the elevator skin and trim tab hinge acting as the bread on both sides, and the spar flange stuck inbetween as the peanut butter, jelly, salami, or whatever sandwich fixin you prefer! Pic shows the bottom flange dimpled - still need to countersink the holes on the top.

Next is a pic of a K1100 platenut for a number 6 screw that will hold the trim servo access panel in place on the bottom of the left elevator. Any platenut designated as 1100 means that the center hole with the threads for the screws comes pre-dimpled for the screw head. A platenut designated as 1000 is NOT pre-dimpled. This pic also shows the mounting hole for an AN426AD3-3.5 flush rivet that will attach the plate nut to the skin. The holes for the rivets need to be dimpled in the same manner that the skin is dimpled so that everything lines up for the flush head rivet correctly. Note for builders, I ordered a small radius dimple die from Cleaveland tools some time ago that I have used in several places since. It has a smaller radius than the standard sized die which works great for dimpling the mounting holes of small platenuts. Your only other option is to grind down a set of standard dies yourself,which is also entirely do-able.

This one is a bit blurry but shows the ehole nut plate ready to install:

Next is a pic of the trim tab servo access cover that has also been dimpled for the number 6 screw that will insert into the platenut attached to support bracket. I have also written orientation arrows to help me remember which way the dimples needed to be set.

If you click on the pic to enlargen it you can also see the edges of the platenuts sticking out on the inside of the support bracket on the left side of the pic. I will need to file these down so that they do not interfere with the placement of the trim tab servo mounting brackets that will be attached to the access plate. Lots of detail work goes on here to make certain that the trim system is installed and functioning absolutely perfectly for reasons I have mentioned in previous posts.
Next is a very dark pic. What I am trying to show here is the flat edge of the male #6 screw dimple die that I had to grind down on my grinding wheel just a bit. this die is a bit larger in circumferance than the number 30 or #40 sized dies that I normally use. As such, it just caught the edge of the skin that overlaps the support bracket when I tried to dimple the screw hole in the center. So I flattend out one side just a bit and problem solved.

I don't think I will finish everything before I get to 400 hours total time on the empennage. That would have been a nice round number to pic as a finish goal. Unfortunately there is still a bunch of drilling, prepping, dimpling, priming, riveting, and edge rolling to do, and then comes the mounting  to the HS, and drilling out the location of the bolt through the center bearing of the HS and control horns of the elevators, drilling out hinges, and mounting and testing the trim servo and the remaining trim tab assembly. So close but yet so far.

As I mentioned to my friend and fellow builder Steve the other day, you just keep doing the things that need to be done each day, and then one day you have an airplane that needs to be flown. It will happen if you just keep at it. My motivation is very simple - all I do is read the posts from other builders/pilots who have made the journey and finally made it to that coveted first flight. Every single one of them says to keep building, because the end result is absolutely worth every minute and every dime spent to get there.

KPR......

389 hours on the hobbs - left elevator and trim tab progress today

Picked up my tools from the chapter 301 auction held recently. Short story about this is that a member of the chapter passed away recently after a losing bout with cancer, and he essentially donated his hangar and it's contents at KFTG to the chapter. After resolving some legal issues, including the sale of his almost completed T-51 kit to a bloke in Australia, a large assortment of tools remained, and these were auctioned off to chapter members by email. This was the first time I had ever done an auction via email, but it was rather fun.

I ended up with a set of nut drivers, 3 impact wrenches, one air drill, and an assortment if impact sockets and other odds and ends. They basically sorted the tools in the drawers of an absolutely humungous tool chest, took photos, sent them to the bidders, and started the auction which ran for about 2 weeks. The tool chest was also auctioned off to the tune of about $450.00.

Thanks Jack for the opportunity to take care of your tools - rest in peace and I won't let ya down. I almost bit on buying the T-51, which is a kit version of a P-51 fighter, but I was already into my own project and did not want to derail that effort. Sad thing is, he was almost finished with it - even had a Corvette engine ready to put in it. Whole thing went for about $35,000.00.

As for the build - I spent time on the trim tab today. Got the skin bent and primed up, and drilled the holes for the hinge on the trim tab side. Also put the lead counterweight back on the drill press after verifying that the drill bit chuck and my work table were at prefect 90 degree angles to each other. Funny thing about that is that one of the lead plugs I had poured into one of the holes the other day was completely pushed out during the drilling, and the other came out as I was final drilling the hole in the E713 counterbalance skin. Oh well, that means my original holes were close enough I guess.The good news is that everything came out OK this time, but I still need to finish match drilling all the holes in the new E704 part. I also had to rebend the flanges to 90 degrees, and flute it just a bit to straighten it out.

All primed up

We pause this trim tab episode momentarily for a trip back to the tip rib assembly. Here is the problem I spoke of in previous posts. The hole on the right is much too close to the bend in the flange. This is the 704 counter balance rib that I had to replace with a new one.

Next is a side view of the trim tab after the bend, with the forward TT spar clecoed in place. As far as I can tell from doing some preliminary fitting to the elevator, everything should line up perfect if I get the hinge placement correct:

Next are the rivet lines I drew on the piano hinge that will attach the trim tab to the elevator. After much research over the past few days, I resolved that the solution to the rivet hole location problem where there would not be enough edge distance if you follow the 1/4 inch measurement in the plans, was to keep the 6/32 edge distance by measuring from the outside edge of the hinge. As it turned out, when I drew the lines per the measurements I just mentioned, the rivet line is pretty much centered in the main part of the hinge flange, just as it should be, and there is also sufficient edge distance for the rivets. Pics are of lines drawn on both sides:

My research on other builder sites regarding the hinge issues revealed so many little tips and tricks to ensure that this gets done correctly, that I will list most of them here to hopefully benefit future builders.

1. Van's drawings showing the hinge assembly are confusing. One drawing seems to show the eyes of the hinges facing upward toward the top of the skin, while others show the hinge eyes facing downward. DOWNWARD is the correct placement. This allows you to adjust the placement of the hinge flange on the elevator side to ensure proper alignment of the trim tab with the elevator, without the eyes getting in the way of the edges of the skin. It also keeps the hinge line flush with the skin and not sticking up into the slip stream, thereby reducing drag.

2. When drilling the holes in the hinge, you have to mark a line, clamp the hinge to the skin and spar under the prepunched holes, and drill complete holes in the hinge flange - they are NOT prepunched. Also make certain that you DO NOT dimple or countersink the holes in the hinge. The dimples and countersinks are in the spar and the skin - NOT in the hinge. Upper skin gets dimples, the top of the spar gets countersunk, and the hinge just gets drilled with a hole to accept the remaining rivet shank.

3. After drawing your reference lines in the hinge flange, remove the piano hinge pin and separate the hinge halves. I use a 3/32 " punch pin for this.Then clamp the hinge half in place lining up the previously drawn reference line and prepunched holes in the skin as a guide.

4. When riveting the hinge flange, remember to put the piano hinge back onto the eyelets (just the pin and not the other half of the hinge). This helps keep the eyelets from bending or distorting during riveting, which may cause binding when you insert the pin and attach the other half of the hinge.

5. Another tip during riveting is to install the other half of the hinge with the hinge pin, and place the other half of the hinge at 90 degrees to the half that you are riveting to provide even more rigidity during riveting.

6. When trimming the end of the hinge on the inboard side of the trim tab, do NOT trim the hinge pin - only the flanges. Leave the pin at it's original length so you can form the bend or at least have something additional to grab on to to remove and insert the pin easily.

Here is the drilled hinge on the trim tab side in progress and almost complete. Use as many cleco clamps as necessary to keep the hinge from moving while drilling the holes. Start at one end of the hinge and drill each hole in sequence until you reach the other end, to ensure that there are no sags in the hinge line. Van's wants the hinge to be placed laterally so that the outboard edge of the hinge is 3/8" from the nearest hole on that side:

And here is the view from the front side of the trim tab after the hinge line has been drilled. All my holes came out right were I expected - centered on each line - both top and bottom. Be sure to keep your drill straight. You have to be patient and have a steady hand because it takes several seconds for the hole to be drilled through the hinge material - even with a sharp drill bit and my super duper and super expensive Sioux air drill running at full speed. Use the mirror technique by aligning the drill bit with its reflection in the alclad trim tab skin - works like a charm every time for drilling straight holes. Let the drill bit do the cutting and don't force it.

And here is the lead counterweight installed in the tip rib assembly. The bolt has been inserted on both sides (only one side showing in this pic). Boy am I glad that is almost over. I say almost because I still need to the following things before it is ready for the next step:
- match drill the 703 to 704 attach holes
- Match drill the 704 flange attach holes to the E702 forward spar
- Dimple the E713 counterbalance skin holes after making sure that they are sized properly and deburred well to prevent cracking when the huge number 10 dimple die is used to make the dimples.
- Countersink the E714 lead counterweight to accept the dimples from the E713 skin

Then I can finally attach everyting to the foward spar so I can final drill the remaining holes in the elevator skin.

Remember - this counterweight does NOT get trimmed like the one on the right side due to the weight differences with the added spar, trim reinforcement brackets, and trim tab assembly all aft of the elevator hinge line. This requires more weight to counter everything added to the left elevator, so you do NOT trim anything from this counterweight.

This shows a much better placement of the screw on the E704 rib side. Still not centered in the flange, but good enough to accept the washer and the nut that will snug it down tight.

Just to recap what I did to fix the problem:
- Filled the holes in the lead counterweight so I could re-drill them after getting a new E704 rib from Van's.
- Attached the new E704 rib to the existing E703 tip rib. I kept the same tip rib since everything seemed to be Ok on that side.
- Attached the counterbalance skin and the counterweight to the tip rib assembly, marked the lead counterweight using the holes on the front side of the E713 with a sharpee, disassembled everything, and step drilled the counterweight on the drill press  - just as I had done before.
- reassembled the counterweight and tip rib/counterbalance skin, and drilled the holes in E713 to size to match the holes in the counterweight. (Drill to Number 12 initially, but will end up being number 10 for the dimple die.) Used my hand held air drill for this part.Tried my best to keep a straight line....
- Verified the hole on the forward flange of the tip rib side aligned with the hole in the counterweight and the counterbalance skin - it did (Whew! was worried about that one)
- Took my number 12 drill bit on the E704 side, slid it through the E713 skin, through the lead counterweight until I felt is stop against the forward flange of the E704 rib. I did not run the drill while doing this - just inserted the bit to verify it would travel all the way up to the point of hitting the solid flange of the new rib.
 - Then I carefully aligned the drill bit - hedging a bit more with pressure toward the outer edge of the rib flange, and HAND TURNED the drill bit to start a reference hole in the flange, being careful NOT to drill all the way through the metal
- Disassembled the counterweight adn ribs one more time, found the mark on the E704 rib, verified that it appeared to be in the correct place to provide a hole with sufficient clearance for the screw, washer,and nut, and finished drill the hole in the rib flange.
- Reassembled everything again to verify that the screws, washers, and nuts on both sides will attach correctly.
 - Now I just ahve to take it all apart again to countersink the holes in the counterweight for the E713 dimples, which also have to be done. Then I put it all back together again, minus the counterweight, so I can attach it to the E702 spar and the skin.

WHAT A PAIN IN THE ASS THIS IS!

Lastly, back to the trim tab. Started measuring for the riblets using the practice kit ribs I got from Mike Rettig a while back.

Here is the outboard or smaller end of the trim tab - will have to fill the areas with the chipped primer - interesting. A very small riblet goes in this end.

Next is a pic of the practice kit rib. I will use 2 of these and the end of a 703 tip rib to make all the necessary riblets.

Next is a pic of some dimesions that I had ruffed out. I will be changing these slightly after reviewing the pics on Steve Riffe's log. The forward spar of the trim tab is a Z shape, and what you end up doing is trimming these riblets so that the rib web coveras as much of the tip area as possible, while making recesses in the flanges of the riblets to ensure clearance from the trim tab spar flanges.

Steves riblet seems to be a bit longer than the dimension I drew up. It is very close to a tooling hole, so I need to be careful about where to cut the tip off.

Next steps for tomorrow, which will finish up my vacation and holiday time off from work - dimple and countersink the spars, fabricate the riblets and drill the rivet holes, and maybe prime all the parts since the weather will finally be somewhat warm again tomorrow. The last part of the left elevator assembly involves aligning the trim tab, drilling the elevator side of the hinge, and then working on the trim servo mounting brackings and nut plates. Then I still have to roll the leading edges....UGHHHH. It just goes on and on and on.......

Have to stay focused on this to get it done, but I really, really, really want to get started on my Wings.

387 hours on the hobbs - pics for previous posts and working on the trim tab

So yesterday, aside from eating the annual feast, I spent time working on the plane as much as I could, while waiting for my parts to arrive from Van's, which did not show up on Wednesday as I had hoped. Mail always gets bumped on the biggest travel days of the the year. How do I know that? Three seperate stints in my earlier days busting bags for three different airlines, that's how. Stupid Holidays. Anyway, I digress. Plenty of work to do regardless.

To catch up a bit, lots of text and and no pics for the past few posts, so here are some pics....
First is my smelting pot  - the olive can bent into shape foe melting/pouring the lead:

The lead counterweight, dog dish, and dirt, after the pouring had been done. Note that there are no holes in the lead any longer, after spending over an hour drilling them out the other night. I love progress! Not shown is the aluminum foil that I had wrapped around the entire part and cut the holes out so that lead would only end up going down the holes and not globbed all over the rest of it.

This is the inboard side of the trim tab, marked 1/8 inch inboard of the true cut line. I ended up cutting the tabs off right to the cut line and deburring them on the scotch brite wheel. Two hands on the dremel tool adn careful cutting here.... Really trying hard to make this a one-trim-tab effort.

Next is the line to cut the tabs off of the elevator. There is some detail about this in the plans worth mentioning here. Question is where do you decide to draw the line, and based on what reference? Answer is that the plans say to place a square angle up against the trailing edge of the elevator where it is cut out for the trim tab, and draw a line perpendicular  to that line for the "bend" line (in my case it is a "Cut" line). All fine and good, but you still don't know exactly where to draw the line - without carefully revewing the plans that is.

What I did is measured the length the trim tab skin at the leading edge - came out to about 17 and 22/32 inches. I then transferred that measurement from the inboard trailing edge of the elevator, outward that same distance, and made a mark. I then took the square, aligned it with the TE of the elevator, and drew the line across the tab on that mark.
This should allow the skins from the elevator and the trim tab to just butt up against each other, but you don't know for sure until you get the trim tab clamped into place.

Only problem with this is, when I look at other sites where people have bent the tabs over, the gap in the strain relief cutout at the bottom and top of the two above pics is MUCH smaller than what my mark indicates. IOW, the bend line is at a point that is actually a bit longer than the line that I drew.

Back to the plans to sort this out - Van's calls for a MINIMUM gap between the trim tab and the elevator of at least 3/32 inches to prevent the possibility of the two components from binding while under normal flight loads. So when I add that distance to my original measurement, it then looks much closer to the bend line I see in other builders logs. My approach was to go ahead and cut the tabs off the trim tab skin flush to the outside edges, since this is the final bend line that is called out in the plans for the trim tab. I then left a healthy amount of excess material on the elevator so that I can trim it up only as necessary once I start fitting the trim tab in place to achieve the optimal 3/32 inch clearance. Don't want to cut too much off and end up with too wide of a gap, which will add drag and not look very professional either. This is actually another plus for choosing to install the riblets instead of bending the dreaded tabs, because you can cheat a bit by moving the webs of the riblets on both the elevator and trim tab in or out to create the correct gap. Just have to be sure to maintain proper edge distance for the rivets that will insert into the flanges of each riblet.

How did I cut the tabs? I used the dremel tool and the reinforced cutoff wheel just as before:

First cut finished, next step is final cut and debure the edge so it is flush with the edges on both ends of the tab.

Pieces after the initial cut was performed

The last pic above shows the dremel tool and flex cable/cutoff wheel setup. What is not easily seen is that I have a 2x4 block of wood between the elevator skin where the clamp is located. I did this to provide some rigidity to the elevator skin where the tabs are located. You do NOT want the skin flapping around while you try to cut these tabs off. The tabs on the trim tab skin are relatively easy to do, because they are on the ends, but the elevator tabs are surrounded by vital areas of the elevator skin that cannot be compromised, or you will be purchasing a new elevator skin. So utmost care must be taken when trimming the tabs from the elevator. Both hands on the dremel tool, moving slowly as you get closer to the TE of the elevator. If you are worried about this, you can cut it up to a certain point, adn take a pair of snips or cutters to remove that last portion nearest the elevator skin.

Next you can see the inboard bottom trim tab edge, all cut and deburred, with the trim tab servo push rod control horn clecoed into place. This is the attach point of the clevis from the trim tab servo to the trim tab that will make it go up and down.

I read a post on someone's builders log that has me pondering this a bit. He pointed out that the two halves of the control horn are not riveted together for some reason - instead, each half of the horn is riveted separately to the skin. Yes, they do butt up against each other fairly well, but he pointed out that this is a potential collection point for moisture, and is therefore susceptible to corrosion over time. For reasons  I have stated in previous posts, this is not an area where you want to take chances or do a poor job of completing the trim tab. It can cost you your life someday, so it warrants careful consideration for preventing moisture from getting in between the two halves of the control horn. Suggestions are to use proseal, which I have none of yet, prime it, seal it, RTV, etc. I will put primer on these parts but I am not sure that this will be enough. Even more curious is why Van's does not to rivet the horn halves to each other. I find this quite strange for such a highly concentrated load point where the pushrod attaches to the horn.

Note the top of the pic where the clevis and the attachment pin have been inserted into the hole at the front of the horn. I also deburred this hole but did NOT run a drill bit through it. The last thing you want to do here is to enlargen the hole where the clevis pin is inserted. You do NOT want excessive play here or it may lead to problems trimming the airplane later on. Some folks choose to insert a cleco in here as well. I chose not to do that either. The clevis pin needs to just fit inside the hole adn be somewhat snug, but not binding

Lastly, here is a pic of the flop tube I received in a previous parts order from Van's:

I spent a considerable amount of time studying the plans for the wing tanks so I could understand how the flop tube assembly differs from the standard fuel pick up line assembly. the flop tube does exactly what it implies - it will "flop" from top to bottom and from side to side of the fuel tank so that when I am upside down and making cork screws in the sky, the engine will still be able to draw fuel from the tank. My system will contain one flop tube in the left tank, while the other tank will have a standard fuel pickup line, so all aerobatics will be done with fuel selected from the left tank.

I then studied the plan diagrams that show the plumbing of the fuel system into the fuselage. I now think I have a fairly clear understanding of how the fuel pickup lines and vent lines are routed through the fuselage from the wings. Amazes me how many 90 degree bends there are in the lines and fittings. If I did that in a 2 cycle RC airplane engine it would not stand a chance without some type of pump system in place. I guess the RV is the same way, in that I think it will have three fuel pumps installed - 1 auxiliary pump for each tank, and the engine driven fuel pump.

Hoping that my parts arrive today - Black Friday. Next steps are to drill and coutersink the trim tab front spar, elevator rear spar, prime the inside of the trim tab skin, bend the trim tab skin TE, align and drill the holes in the piano wire hinge, and fabricate the three riblets. Lots of stuff to do, but none of it overtly time consuming. Also read up on the hinge placement. Turns out to be another area where Van's is severely lacking in detailed info about this. A lot of confusion about how to mark the holes in the hinge, and the sequence of drilling, dimpling, and countersinking that must be done in the correct order to get it right. Study every detail in the plans, think it through, and it should come together just fine.....

385 hours on the hobbs - learned how to smelt lead today

I decided to try to fill the two previous drilled holes in my lead counterweight so I could start over and redrill them after my replacement parts arrive from Vans hopefully tomorrow. To do this I had to melt some lead and pour it back into the holes that I drilled the other night.

My wife's side of the family always has Thanksgiving te week prior to the official holiday, and this year it was at my house. So lucky for me this meant that I had my pick of tin cans to choose from for melting the lead. I chose a small can of olives, washed it clean, dried it thoroughly, and then pondered how best to try to accomplish this, since I had never done anything like this before.

I started by stripping off the paper around the can, then bending a pour spout in the top of the can so that I could direct the molten lead to the correct point and not make a total mess. Then I tried inserting some of the drill strands that I had saved from the first counterweight that I fabricated for the right elevator. I put the scraps in the can, the can in a pot, and the pot on the stove, and turned on the heat. This did not work so well.The lead only half melted and would not get to a state where it could be poured.

I guess I should cover the other part of the preparation. I wrapped aluminum foil around the counterweight, leaving only the holes on one side exposed where the molten lead would be poured. I then took one of my dogs water bowls, filled it with dirt, and placed the couterweight inside the bowl on the dirt. This is supposed to act as a foundation for the mold, and also to help disperse the heat. I then took a set of locking pliers, donned some heavy leather work gloves, and attached the locking pliers to the edge of the can on the opposite side of the pour spout.

So now I had to figure out what to use to heat the lead? I also figured that I was going to need a bit more lead than just the scraps that I had collected. So I remembered that I a propane welding/soldering torch, and I also remembered that I still had the large slab of lead that was trimmed away from the right side counterweight. So I threw the slab in the can adn lit the torch and started heating things up. This did the trick. The lead melted after a minute or so of direct heat on the bottom of the can. I quickly poured it on the counterweight in the dog dish. Man it comes out fast!. So I had to do some trimming to remove the excess, but all that ook was a coping saw and a few cuts to break it free.

Now my only concern is that the lead has definitely filled the old holes, but it does not seem like it attached itself to the existing lead that surrounded the holes. So in essence all I may have done is to pour a couple of plugs to fill each of the holes, and I am not sure how this will work out when I try to redrill them. Oh well, I guess I wil find out - hopefully tomorrow. If it does not work, then my options are to make a mold of the entire counterweight and repour the whole thing, or order a new counterweight for 17 bucks plus a large amount for shipping due to the weight.

I spent other time today working on the parts for the frame and studying the plans for the Wings. Match drilled the elevator ribs to the spars, and countersunk the designated rivet holes per the plans. Will make final decisions/measurements for the Wing jig tomorrow.

384 hours on the hobbs - another step forward and two steps back...

If it was summer time in Colorado, perhaps having these difficulties would not matter so much to me. But when you have to fight the cold and the wind outside, it just makes these little dips in the road that much harder to take. The step forward was bending the trailing edge of the left elevator yesterday - very much a non-event, and everything turned out as expected. Dare I say I think I have the hang of bending trailing edges now. Unless there is any bending that takes place during the fuselage construction (Longerons I think), I think that the only things left to bend are the TEs of both ailerons during the Wing construction.

Here is the elevator skin in the bending brake, with the forward spar clecoed and clamped in place to serve as a reference for when the bend has gone far enough.

I clamped the center portion of the spar to the skin since you cannot get clecoes in the rivet holes in that area because the web on the spar is not wide or tall enough to fit clecoes inside the flanges.

I am including this next pic as a "Don't do this" photo when you bend your trailing edges. Do NOT place the end ribs on either end of the spar prior to bending the trailing edge. I did remove this rib prior to bending. I only put it there to help stabilize the placement of the forward spar and to check the angle that I was looking for at the root after the bend was completed. If you leave it attached you may not get the correct bend in the skin and that would be bad and possibly expensive to fix:

And here is the tip after the bend. The nice thing about bending this skin is that it is MUCH easier to bend than the other skins, since just under half of the trailing edge has been removed for the area that will be populated by the moveable trim tab. ON the other hand, it does make this a bit more awkward because you have to double check to ensure that the edge is positioned exactly where it needs to be, which is a bit more difficult due to the loose skin flopping around on the inboard side.

Notice the duct tape on the edge of the tip to keep the bottom skin from sliding forward as much as possible, and the flush edge up against the hinge line. This method has worked well for me thus far. There are all sorts of other posts out there talking about using 1/8 inch dowels to keep the proper radius of the TE, or placing the edge a certain distance forward of the hinge line, etc. I have found all of this to be unnecessary. What I did do was tape down both bottom edges, added a 2x4 in front of the brake and under the skin to help support the bottom skin that hangs out of the bending brake so as to prevent the bowing of the bottom skin, and  placing the edge right up against the hinges before starting the bend. Works well enough for me.

Here is the shot from the right side. That curved tab will get cut off later.

Close enough from the top of the forward spar for me. The slight bow in the pic below is known as "ballooning", and if I really wanted to, I could keep trying to work that out until it was completely flat, but I don't think that this is necessary. Van's says to get it on top of the spar or "close" to it, so that there is not excessive stress required to hold the skin onto the spar. Strangely, this is exactly the opposite of the way that the skins for the Horizontal and Vertical stabilizers are applied to the frame. They are bent from the front side and attached to a spar at the back, so those skins are supposed to be stressed by design I guess, and they must be held down with clecoes to keep them from springing back up again.

Pic is a little confusing because the right elevator is sticking up in the back ground. So for clarity, these pics show the elevator from the front, with the forward spar web standing vertically, and the top left elevator skin shown draped just above the top edge of the forward spar flange to show where the bend ended up on the front side. If that fails to clear it up, just use your imagination! :)

Looking at the bottom side after the bend:

A blurry pic of the root end of the bend. I was still looking for about a 1/8 inch radius for the final bend. You will find that to get this raduis you will need to force the brake down to the point where the stiffeners from each side of the skin just start to contact each other. As long you do not forcefully smash the skin down to this point, and simply keep applying constant, steady pressure on the brake until this happens, you will end up with a nice crisp bend in the TE, which is what you want.

this bottom skin above looks a little bit bowed, but that is because it is sitting on top of my foam pad with no other structural support. So don't be fooled!

Next, I drew lines on each of the tabs that are going to be cut off. I marked them where the bend lines are supposed to occur, which is parallel to the line of the rest of the edge of the trim tab and elevator per the plans. I will then add another line about 1/8 inch further outward toward the end of the tab from each of these lines to ensure I have enough excess material to trim to final size after the hinges are installed on the trim tab and it is positioned on the elevator.

And now for the "2 steps back" part of this post. With the elevator skin bent successfully, time to work on the tip rib and drill that pesky lead counter weight.

Here is the rib assembly clecoed for match drilling onto the forward spar. Same way that was done for the right elevator.

Problem came after drilling the lead counterweight. I found a builders web site after completing the right elevator that mentioned the use of the drill press, and what seemed to be a better approach to drilling out the counterweight and corresponding holes in the counter balance skin and the forward flanges of the E703 and E704 tip ribs. The steps were basically to attach the rib and counterbalance assembly per the plans, but instead of free hand drilling the lead with the hand drill, simply mark the holes on the lead with a sharpee where the pilot holes on the front of the counter balance skin are located. then you disassemble everything and put the lead counterweight on the drill press and drill the holes to size. Then you put it all back together again and final drill the holes on the counter balance skin and then finally all the way through the lead weight and onto the forward flanges of the two ribs. Doing it this way seemed as though everything would line up just perfect, right?

Well, I think my big screw up may have been setting a 2x4 on the vise on my drill press so that it was level according to my bubble level, instead of ensuring it was PERPENDICULAR to the drill bit. I think this actually created an angle other than 90 degrees between the lead counterweight and my drill bit. Long story short, one of my holes in one of the ribs turned out to be just wide enough for the washer and the nut to be placed on the forward flange of the tip rib, similar to how it turned out on the right elevator.

Unfortunately, the hole I ended up with on the counterbalance rib flange was way too far inboard. Result - part ruined, hole dimensions in my counterweight are now suspected to be incorrect, and I need to order more parts and then ultimately learn how to smelt some lead to fill the holes in the counterweight and start all over again. I was too disgusted to take pics of this last night, so those will have to wait. Ordered a new counterbalance skin and counter balance rib from Vans today so should have those in a couple of days, hopefully before the holiday.

Next time I will do the following a bit differently:
1. Ensure that the counterweight is SQUARE to the drill bit instead of LEVEL to the ground - stupid me!
2. Drill a 1/16 inch hole through the lead counterweight on the drill press instead of drilling the final sized #12 hole for the screw. I will then take the counterweight with the small holes and drill through the entire assembly to see where the stupid hole will end up on the forward flange of the rib. At least this way I can tell how I need to adjust the hole, if at all, before I commit to drilling out a large hole and screwing up the hole thing all over again.

Once I know the hole is correct, I will disassemble the parts again and finish drilling the hole in the drill press.

And as a last thought before I close, let me be perfectly clear about the settings and drill speeds I used to drill out the counterweight on the drill press, which actually worked out pretty well:
1. I step drilled the counterweight just as I had done before. This allows removal of small parts of the lead without seriously bogging down the bit. I started with #40, followed by #30, #28, #21, #19, and finally a #12 bit

2. Drill press was set to 3100 RPM - as fast as it can go - I did not change it to a slower speed at all.

3. Used 3-in-1 oil RELIGIOUSLY for this. that means drill about 1/8 to 1/4 inch at a time, stop the drill bit, clean it off, re-oil the bit, drill another 1/8 to 1/4 inch, wash, rinse, repeat.

4. Technique to is be VERY SLOW with the press. I also would set the stops on the press so that the drill bit would not go all the way down initially. I would leave it about 1/8 inch high, and finish the hole by setting it down all the way once the drill had removed all the material down to that point.

5. Be sure to apply pressure to the press bar, and then back it all the way out to remove the slag. If you have the bit properly lubricated you should see small chips come out, and not see too many groove-filling slivers come up. Slivers are bad and may cause you to mis-direct your hole if you are not careful.

6. Took a while to do it this way, but the holes got drilled out as straight as my settings would allow.

Hard part about this is not being able to clamp the lead. If you try to clamp it you will distort its shape and will have to melt it down and reform and start all over again, or order a new one from Vans. This was even harder because my drill press caused the weight to vibrate quite a bit. Not so bad when you start out, but after the 2x4 got a bunch of oil all over it, it got very slipperly. I have a laser device on my press so I can keep a relatively good reference to the hole position and the drill bit. So I held the weight with my left hand and ran the press with my right.

Out of all the trials and tribulations I have endured thus far on this project, I would have to say that drilling non-pre-punched holes through multiple layers and thicknesses of dissimilar metal has to be the most challenging thing to do.

So hopefully that provides enough detail for those that may follow so that you don't screw yours up the first time around!

Welcome Captain Buzz!

I noticed you joined my blog site as a follower. Nice to have another experienced builder chiming in! Welcome!

382 hours on the hobbs - Sometimes taking the small victories is good enough!

Got another stiffener angle from Vans and remade the E720 L stiffener than became damaged in my previous attempt to get them back riveted to the left elevator skin. I have also realized that I have not posted any pics in several posts so it's time to change that. So bear with me while I take a short trip down the past.

Here is a shot of the measurement for the E720 L stiffener where Van's wants you shorten the back end by a specified amount from the second to the last rivet. In this case the measurement is 2 inches from the hole.

And now for something I just could not pass up, even though it is not exactly airplane related. Back up on the mountain for some deer hunting. My son Adam was able to hunt this year so we both went up the mountain to see what we could see. So with that in mind, I ask you, what is wrong with this picture?!

And here is one with the skin being dimpled using the C frame. No extra holes poked in the left skin like I did on the right elevator skin - thank goodness for that!

All the stiffener holes dimpled. One thing about this process that I do not like. Since you don't really get to match drill any of the other holes for the attach points for the spars and ribs until after you bend the trailing edge of the skin, you are forced to prime areas with holes that are both undrilled to final size and that have not been dimpleed yet. Some have questioned the integrity of the primer if you primer first and dimple later, but I ahve not seen any appreciable flaking or detatchment of the primer from the area where the dimple was formed, so I guess it's not such a big deal.

Napa 7220 self etching primer in a can being applied to the stiffeners and the trim server mounting access plate, etc. My little chicken wire paint box works quite well for the smaller parts.

Inside left elevator all scuffed up with scotch brite pad (maroon) and cleaned with microfiber cloth and acetone. Ready for primer.

Too bad halloween is over! Warning! The following pic is very grotesque and not for the faint of heart! You better watch out if you get a can of primer in my hands - lethal and extremely dangerous for sure!

On a more serious note - please, if you use this stuff, remember that it contains ACID that EATS METAL. This is about the last stuff you want to be breathing, so the mask is an absolute MUST, even though the primer comes in a rattle can that looks like any other spray paint in a can. Here is the skin after priming. I really like the way way this stuff lays down.

Tape applied to the rivets for back riveting the trim access plate and the the stiffeners.

The trim access backing plate after back riveting. Interesting to me that the side next to the forward spar has NO rivets to hold it on the skin. I think the curved flange sits up against the back of the spar but not 100% sure about that. The other holes that you see are for the nut plates that will secure the cover. Some additional holes will drilled as well to accept the rivets for the two brackets that will hold the trim servo in place.

Stiffeners on the bottom back riveted with no problems.

And then the problem occured. I was on the last stiffener E720L. Although it is hard to see in the pic, the area where the primer is scratched off is the side of the dimple that became completely caved in. Even worse is that it happened to the very last hole in the stiffener, closest to the trailing edge of the skin, where a lot of stress can occur. Not a great place to have a potential defective part or assembly. How this happened is still a huge mystery to me. The only thing I can figure is that I did not adequately hold the skin back far enough to clear the rivet gun set retaining spring, and the back rivet set may have slipped to the side and started driving the rivet at an angle. After two attempts to drill out and reset this rivet as per my previous post comments, the stiffener was damaged beyond usefulness.

The last two pics are the result of many steps to fix the problems that this caused:
- fabricating a new stiffener to replace the damaged one
- setting the skin back on my close quarter dimple tool to try to reshape the dimple in the skin so that the 1097 4-3.5 Oops rivet head would sit more flush after drilling the hole to 1/8 inch to accept the wider diameter oops rivet
- using a 1/8 inch drill bit and the same sized hole in the skin as a guide to mark the surface of the center of the last hole in the stiffener. Remember that Vans makes you drill this final hole in it's entirety. It is not predrilled like all the other holes, so you have to drill this hole out all the way.
- drilled the hole from the previous mark using a #40 drill bit first, so that the correct 3/32 dimple could be formed arund the hole
- dimpled all the stiffener holes with 3/32 dimples
- drilled the last hole in the stiffener a bit larger to 1/8 inch using a #30 drill bit so that the oops rivet would fit through the holes in both the skin and stiffener
- primed the stiffener
- inserted and taped the rivets into the skin, ensuring that the 1097 AN4-3.5 rivet was in the last hole, and the normal AN426AD3-3.5 rivets were in all the other holes
- Got my kid outside to hold the skin back so I could focus entirely on holding the back rivet set steady and the stiffener firmly to the skin
- Successfully back riveted set all the rivets on this last stiffener.

The pic above shows the oops rivet sitting nice adn flush on the skin. HEad is the same as the other rivets, but the shaft is thicker. WHEW, am I glad that worked out.

So I have officially set my very first oops rivet. An interesting thing about these rivets is that they have a slightly raised center section on the manfactured head side that you don't see on the regular AN426 flush rivets. This initially caused me to think that the rivet was going to sit a bit proud of the skin, but in reality it sits just as flush as all the other ones. Another concern was proper rivet length. I was not sure that using a 1/8 inch thick rivet of the same length as the AN426 flush rivets would result in the proper shop head dimensions, but this seemed to work out just fine as well. Checked it on my rivet gauge and everything seems to measure up correctly. I am still a bit concerned about clearance with the rivet head on the opposite side of the skin once the trailing edge is bent, but I'll worry about that later. For now I am just glad that I got the stiffener replaced and riveted to the skin correctly.

There - all caught up now!  Next is bending the trailing edge of the skin and trimming off those pesky tabs.