Saturday, March 18, 2017

Wings- Ribs


These are my wing ribs all deburred.

The two yellow spools are the sandpaper I used for deburring the holes and flange edges. I also used just a loose sheet of 220 grit pinched between my fingers for the long straight flanges. The abrasive spools were a 1/16" rope and a 1/4" flat ribbon. This worked really well. I probably used 25% of a 25 foot roll. Many of the rib flanges were fairly well deburred already, so it didn't take much more for me to be satisfied. The lightening holes needed the most effort.

I also built the rib flange forming thing-a-ma-gig sitting on the table. It forms the flanges to the perfect 90 degrees to the rib web. It works very well. However, when I tried it out, I grabbed a nose rib and looked at the flange. It measured almost perfect without me having to touch it. Then I looked at the center rib, seems perfect too. Did I spend half a day and $20 on this thing for nothing? I will finish up checking the flange angles tonight. But I will probably be too embarrassed to tell anyone how useful, or useless, this tool was. It is well worth the effort to construct for the flanges on the tail ribs, wish I had it then. But I hope I never have to  rebuild the tail feathers.

Also in the picture are the mods I plan to make to the ribs. I talked to Van's Aircraft support on Friday and they said what I had planned seemed reasonable. If you wish to follow my example, please check with Van's yourself. So here is my plan: for the nose rib, I will enlarge the internal fuel vent hole from 1/4" to 1/2". (This is not the hole the vent tube goes thru, but the one that will be at the high point when filling the tanks.) The stock hole seems really small to me, and others have complained the tanks are slow to fill. I don't plan on doing aerobatics, nor uncoordinated flight (who does?), so I am not worried if these enlarged holes cause the fuel to slosh around a little more. For the main rib, I plan to follow the supplemental instructions on the Van's Aircraft site and add a hole in the main web to the right of the first lightening hole in the picture. This will be 3/4" per the supplemental instructions. Also the RV9 plans say it is permissible to enlarge the forward tooling hole to 1/2". But the same Van's supplement says the RV7 and 8 can enlarge this to 5/8". I will follow the 9 plans and only enlarge to 1/2 ".

Lastly in the picture, behind the table, are the wings stands for the spars. I plan to build both wings at once. These stands are a God send. Thank you to the builder Billy who provided them.

So that is my plan. Onward and upward, (well not yet anyway) :-(

2018 Update: The extra hole in the  rid I added for the conduit was positioned too low and right over a rivet. this made riveting the skins tough. I think it it was up 3/8" to 1/2 " higher, riveting the skins would have been much easier.

Sunday, March 5, 2017

Starting wings-spars

After having mastered the tail section, now it is time to start taking bigger bites. Goal is to have the wings done by August for a late summer trip to Vans to pick up the fuselage kit. At least this is what I am telling people. The real goal is to have the garage cleaned out enough to get the fuselage kit inside by August.

The wing spars went together fine, but there are some minor things to be aware of. I had to look at a few other builders website and a few pictures of their spars to figure out the plans.(Thank you, thank you, and thank you)

First thing is the inboard spar doubler gets several countersunk holes. 3 of these are for the gap fairing that will have another thin sheet between the countersunk hole and the rivet. Therefore these 3 have to be set 0.007" deeper to allow for the skin. The other countersunk holes just see the rivet so these are set flush. Now there are regular rivets up near the top web. These are called out as standard rivets, but they are very close to the rivets that will be used for the skin attach and am not sure if I can bet a bucking bar on these. I am wondering if these should be flush rivets instead. I followed the plans, because I don't know what I don't know, but I did put the manufactured head on the outside so I could drill it out if I have to switch rivet styles later. Here is a pick of the root doubler and the rivets.


 The tip was fairly straight forward except the plans do not call out leaving out the rivets for the aileron bracket. So only the inboard six holes got rivets right now. Seems this is the same as the root doubler, only 6 rivets installed at this stage.
After these steps were done, it doesn't seem like much was accomplished, but this was a full page, so it is a good start on the wings. Now to deburr and straighten the ribs. And get the wings build jigs bolted to the garage floor.