Sunday, December 24, 2017

The End is Near

The end is near, both of 2017 and this wing build.

The ailerons are finished, and I am quite happy with the results. One aileron trailing edge is dead straight, the second took a little work to get out a very minor ripple; I think the ripple was caused by not riveting the trailing edge together as soon as the pro-seal was dry and letting the trailing edge sit unclamped for a few days. No worries should be fine.

I think the secret to building ailerons with no twist is the leading edge straightness. I spent a little extra time making sure the bottom skin was absolutely flat from the stainless steel leading edge weight to the spar. Since drilling the leading edge is very difficult due to the super hard stainless steel, I ended up having some extra "lightening" holes in the stainless steel bar. During final assembly, I made sure the leading edge ribs sat flat on my super flat surface plate (kitchen granite counter top). Once the leading edge is riveted to the spar, the aileron becomes enormously stiff. I am glad I took the extra time to make this part perfect.
For the trailing edge drilling, I make a simple metal guide; should have done this long ago.

I am currently working on the flaps and planning out the internal stuff the needs to go in before the bottom skins are on. I am thinking I will fully install the heated AoA pitot tube, and the autopilot servo for the future G3x panel. I am planning the magnetometer for the right wing tip and the VOR antenna for the left. So my present plan is to not pull any wires for those until the tips go on in a year or two. The wings already have conduit for the wiring, so pulling the wires should be easy.
As for the lights, I saw some new Baja Design that seem choice, but with the pace of technology, still not sure if I will install now.

Friday, November 17, 2017

Progress too

Making steady progress on the wings. Everything pretty much to plan. One note: the instructions were written long before the extra aileron brace was engineered. So the instructions say to install the aileron brackets before the flap brackets. This build order needs to flip around now. The flap brackets need to be installed prior to the aileron brackets since the extra reinforcing  interferes with the rivets as seen in the picture below.
 One thing to note, the bottom skin rivets can still be accessed with this brace in place; on the RV7, I believe the brace interferes with the skin rivets, not a problem on this RV9.

Moving on now with the flaps and ailerons.....

Friday, September 22, 2017

Wing Skins

 Look no clecos! A few of the rear spar rivets are still not in near the root; it seems these will be easier to squeeze once the wings are out of the build stands.

The easiest way I found to do this was from the trailing edge. Starting with the center rib of each skin, I would rivet the skin to the rear spar between the two center ribs. Then work up from the trailing edge on each rib. I could just reach the fourth rivet above the J stringer by laying on a creeper. 

After each skin was done on the lower portion, I would then corral a helper and rivet each rib the rest of the way up and then the main spar. I found a helper with a tungsten bucking bar was the easiest. I also used a wi fi endoscope camera hooked to my iPad so I could see around the other side and validate each rivet as we went. For $40 on amazon, the endoscope camera was well worth it. After a while, my friend would understand a good rivet and we would move along.

I took advantage of my rivet buddy not wanting to go home (because of traffic, not the wife, so he said) and was able to get all the top rivets on the right wing too. The rest I can get from the bottom with a creeper.

The wing is going slower than I anticipated, but I am taking my time and keeping the quality up.
After checking the twist, everything is as before. I did notice the right skin had to be cleco'd in a certain order to get all the holes to line up, so I ended up clecoing the skins on twice and using a cleco in every hole. There must have been some sag the first time. I am glad I didn't start riveting until both skins were on and fully cleco'd in place.

Sunday, September 3, 2017

Small Steps are Still Progress

As the wing build continues, no real drama. The leading edges went on without much trouble; not nearly with the difficulty I envisioned from reading other blogs. As it turned out, most of the leading edge to spar rivets were reachable with the squeezer. I only had to drive about 10% of them, and of those only 5 on the right wing were blind and needed two people.

For the split strip between the tank and the outer leading edge skin, I tweaked the nut plates to better conform to the skin using a vise and some scrap brackets. This worked out well.

After installing the tanks, I noticed the skin thicknesses aren't all the same. Some are 25 mils , others are 32 mils. I wish I would have beveled the skins before assembly to make this transition smoother, but maybe there will be a chance to smooth the 7 mil step before paint.

I started riveting the skins on with my resident engineer-in-training. I am still trying to work out the best technique. I tried the long offset back rivet tool, but this takes so much umph on the gun the rivet heads aren't pretty; acceptable, but not pretty. So we tried the normal method as in the picture. This worked out well for the ribs, but still looking for a better method for the skin to spar rivets.

Saturday, July 29, 2017

One line One month

I was trying to get at least one page of instructions done per month.
Got the fuel tanks done in two months and that was about two pages of instructions.
Than I ran into the next step:" Deburr, Dimple (prime) main skins"
Really simple sentence, but took me a month.:-)

But this is summer and I am  distracted. Here is my typical view during my Saturday morning runs.
Hard to get into build during the beautiful summer days. But I am making progress, skins are done and am working on countersinking the spar to accept the skins.

I never installed the flush rivets for the ribs that go under the tank skins, so am doing that now. I wish I would have done this when the ribs were riveted to the spars, and before the skins were matched drilled. So now I have to c-sink the ribs holes under the tank to flush, and the ones for the skin to 0.007" deeper per the plans. I will probably squeeze these rivets right after I dab primer on all the spar c-sink holes; this primer may not be required, but I am going to do it anyway, at least for the main spar.
Working on stall warning now. And hope to get the top main skins on before the end of August; although the beach looks mighty inviting.......

Friday, June 30, 2017

Fuel Tanks- Breath didnt Hold

Last report, I was holding my breath the fuel tanks would not leak.

Like all good learning experiences, my tanks leaked; both of them, mainly from the rear seam.

The one tank leaked from the seam near the fuel sender and access hole. This was easy enough to fix by removing the access panel and adding more goop. 

The tank in the picture leaked from the top seam near the middle, in 2 places. Ugh.

There were many options I found on-line to fix this:
1) use Loctite adhesive designed for just such a repair.
2) ignore it and hope it goes away.
3) cut a hole in the baffle, add more sealant and then use a new access plate to cover over hole.
4) use the really thin Proseal that is brushable, pour it in the tank and slosh it along the seam.
5) make a funky applicator with a syringe and tubing; using a USB camera, and add some more Proseal to the seam thru the filler neck or the sender access panel.

Of course, being the expert builder that I am, I did none of the above.

I decided to use option 6), which is not listed above. If that didn't work, use option 3.

Option 6) was to drill out the baffle rivets in the offending area, wrap a towel around the vacuum cleaner nozzle and tape it to the fuel filler spout. With the manometer hooked up, turn on the suction and leave the fuel sender screws out to avoid over pressurizing the tank (wouldn't this be under pressurizing?). Add some Proseal to the seam, and gently open the seam up by gently flexing the tank skin. To my surprise, the sealant sucked itself into the gap. I used a heat gun to gently heat the tank skin to help the Proseal flow into the cracks. The whole time the tank was under 27" of vacuum.

After resetting the rivets, I let the tank sit for a day. I started the pressure test tonight, and the leak check using soap bubbles showed no leakage. Normally I would say done, but I plan to let it sit over night just to make sure.

Sunday, June 25, 2017

Fuel tanks: Stop the madness, I am tired of learning

Fuel tanks are done, Yippee Ki Ya!

This last week has been fun learning how to play with ProSeal. The baffles and support brackets went on without much trouble.

For those of you building a RV9, it is important to note that the baffle doesn't naturally want to sit properly. The top and bottom skins are designed to not sit perpendicular to the back of the baffle.  So when the baffle is dropped in, it has to be forced to align with the internal ribs. Once the baffle was set down on the ribs, I pushed the baffle into alignment and pressed in a  -4 rivet thru the baffle into the ribs. This kept the baffle lined up while I inserted the gazillion silver clecos for the top and bottom row of -3 rivets, and clecos for the rest of -4 rivets for the baffle to ribs, without the brackets.

For the -3 clecos. I pushed in a -3 rivet every 10th hole to line up the skin and baffle before clecoing. Once all the clecos were inserted, I gently squeezed between each -3 rivet location with a Vise Grip welding pliers to squeeze out any excess Proseal.

I started riveting the -3's at the middle of the tank. I found I had to take the countersink (with a countersink stop) and touch up each hole before inserting the rivet; otherwise the heads were not always flush to the skin.

For the baffle to rib to bracket rivets, the pop rivets went in smoothly. I made sure I set the -3 and -4 rivets in one seating so the Proseal didn't have a chance to harden.

The sender, pickup and drain went in as per plans.

I am now in the waiting period when I am ignorant and happy, thinking the tanks are done and won't leak. Here is my leak check setup using the manometer method. I am expecting I can blow in the tubes enough to pressurize them to 27" of water. I am holding my breath hoping they won't leak.