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Archive for May, 2010

A Little More Fiberglass – 1 hr

May 31, 2010 Leave a comment

Monday 31 May,2010 (Memorial Day)

Not a lot to report today. I dimpled the Vertical Stabilizer skin for the fiberglass tip and countersunk the fiberglass flanges. Then I drilled out the holes to accommodate the 1/8 inch CS4-4 pop rivets. Then I laid in a couple of layers of fiberglass on the inside to cover the Last-a-foam and provide extra strength. Here is the lay up starting to cure.

Then I drilled out the holes in the rudder and its fiberglass tip for the 1/8 inch pop rivets.

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Categories: Fiberglass Tips

Still Working on Empennage Tips – 3 hrs

May 31, 2010 Leave a comment

Sunday May 30, 2010

I’ve been making slow but steady progress on the empennage tips. I have to admit that my progress has slowed down a bit since I am wrapping up the work on the empennage and it will be a while before the wing kit arrives.

Today I sanded the vertical stabilizer tip so the epoxy filler is pretty much flush with the trailing edge. This is still a rough cut at the final form. I also sanded the right horizontal stabilizer tip similarly.

Then I sanded the right elevator tip and checked the clearance to the horizontal stabilizer tip. It’s getting there. I also checked the balance of the right elevator. I initially planned to used nutplates and screws to mount both elevator tips so I could remove them after painting to rebalance. However, after seeing a variety of RVs at the recent Chino fly-in and observing how clean the tails look when the tip seams are filled and blended into the skin I changed my mind. I also did some research about the elevator balance issue and it seems that it is not as critical as I expected.

So I decided to just rivet the right elevator tip. But first I drilled a few holes in the lead counterweight to get the balance closer to neutral with just a bit of excess weight toward the front. This makes a nominal allowance for the paint that will come later. If I underestimated the effect of the paint, I riveted a nutplate to the counterweight ribs on this side (like I did previously on the left side) so I can add trim weight at any time after painting.

So many closeups lately I thought I should throw in a wider view of the horizontal stabilizer and elevator just for reference.

I took the elevator tip back off and checked the integrity of the fiberglass. I wanted to make sure its good enough to rivet on. The final fiberglass work will be with it permanently mounted to the elevator. Looks good.

Then I pulled out the pnuematic squeezer and dimpled the skin for the elevator tip. the last hole on each side is tricky because the skins are too close together for the dimple dies on the squeezer. So I put in a rivet and drove it into my homemade countersink tool using the flush set on the rivet gun. That provides about a 50% deep dimple that I then finished up with a slight machine countersink. I just spun the countersink tool by hand using the deburring handle. Then I countersunk the holes in the fiberglass tip flange, again using the deburring handle.

Next I pulled out the pop rivet gun and riveted the tip on. Now I need some light weight fiberglass cloth and a finish filler to start blending the tip into the aluminum skin. Unfortunately I didn’t think about that when I was in Corona yesterday. I could have picked it up at Aircraft Spruce.

The HS tip is not quite ready to be riveted on. I still needed some .020 aluminum strips on the inside of the flanges so I took it off and cut and bonded those in to set overnight.

Categories: Fiberglass Tips

Ordered the Wings!

May 29, 2010 Leave a comment

Yesterday I faxed an order to Vans for the RV7/A wings with a 25% deposit. I considered the quick build wings but the extra cost (at least $5500 including extra crating and shipping charges) was too high for me and I will certainly need that money later for the engine and/or avionics.  The lead time is listed as 10 weeks on the website so I expect delivery in early August. Another milestone on this exciting journey!

Categories: General

More Empennage Fiberglass Work – 4 hrs

May 29, 2010 Leave a comment

Saturday May 29, 2010

The plan for today was go to my flying lesson early (7:00 AM) and work on the airplane in the afternoon. The weather was clear today so the lesson happened as planned, then I stopped at Harbor Freight Tools on the way home to get some cheap craft brushes for mixing and applying epoxy. I also picked up a hearing protector headset for $2.99 on sale. It actually seems to work OK. A bargain for sure.

Today I started the fiberglass layup for the right elevator tip. I applied a layer of plastic sheeting over the lead counterweight first to keep the epoxy from bonding to the weight. Here you see the setup and the fiberglass tip with the gel coat sanded off at the end.

Then I mixed epoxy and laid on two coats of glass. I thought I took a photo of the wet layup but I guess I didn’t.

Then I applied a layer of fiberglass on the inside of the right horizontal stabilizer tip. I sanded out part of the foam to avoid interfering with the rivet line but I left the foam in the inner part of the tip. The glass will encapsulate this and just leave a stiffer structure. Here you can see the cloth laid in place just before brushing on the epoxy.

Then I fit the vertical stabilizer tip to the VS using cleco clamps to secure it initially. I had to cut off about 1/4 inch from the edge of the tip to make it flush with the edge of the skin. Here you can see the overhang before cutting.

Here it is after cutting it to length and drilling through the existing holes in the skin. You can also see one of the reinforcement strips I bonded into the inside to give the rivets something secure to bite into.

Here is a fit check with the rudder and vertical stabilizer tips cleco’d on. The clearance is fine for now. I will glass up the open back face of the VS tip first then I can fine tune the clearance.

I cut a piece of Last-a-foam to close out the trailing face of the VS tip and laid on one layer of 9 oz Rutan BID fiberglass cloth (purchased from Aircraft Spruce).

Then I took a break for a few hours. It was hot today so the epoxy set up pretty fast. After three hours it was no longer tacky to the touch. So I trimmed up the excess cloth around the edges of the VS tip and the right HS tip. I also sanded out the right elevator tip rough fiberglass layup. I was a little too aggressive on it and there are a couple of holes where I sanded through the glass to the lead weight. Not to worry. This is not unusual on the first try. So I removed the tip from the elevator, re-wrapped the lead weight with plastic sheet, and set up to apply a second layer of fiberglass on the elevator tip.

Another small batch of epoxy was mixed and I applied another layer of glass over the first layer being sure to cover the holes. Here is the work in progress.

With the excess epoxy, I mixed in some West Systems filler and put it into the shallow cavities I created on the VS and right HS tips trailing edges. I will sand these to final shape tomorrow.

Categories: Fiberglass Tips

Sanding and Filling – 3 hrs

May 23, 2010 Leave a comment

Sunday May 23, 2010

Well yesterday went by without any work on the kit. I went to a flying lesson at Corona airport in the morning then met Mike Holland, an RV9A builder who keeps his plane at Chino airport. He picked me up around 10:30 AM and we went for a spin in his airplane. The 9A is close to the 7A, the main difference being a higher aspect ratio wing on the 9A. We flew down to Borrego Springs, made a landing and brief stop then flew back to Corona. He has a very nice plane and I was privileged to fly it a little while on the way down to Borrego. It is very responsive on the controls – much crisper than the Cessna 172 I am training in. Many thanks to Mike for the experience.

After that I took my daughter up to Santa Clarita where she will be leaving on a missions trip to Uganda on Monday for six weeks. It’s going to be tough having her gone so far for so long.

This morning I marked the left horizontal stabilizer skin for match drilling to the left tip. The plans provide no dimensions so I tried to match it to picture. The first hole is 1 inch from the leading edge and the next three are 1.375 inches apart. I drilled with a #30 and cleco’d the tip to the skin as shown.

Then I mixed up a batch of epoxy and filler to fill in the trailing side of the tip with a smooth solid layer. I used some blue tape to make a dam around the inboard edge.

After lunch the epoxy was pretty firm so I sanded the material flush leaving a nice solid closeout. I cleco’d it back on and its starting to look pretty nice.

While on a roll, I marked and match drilled the other tip in the same way and cut a piece of foam to size to close this one out also.

Then I dimpled the holes in the rudder for the tip and countersunk the holes in the fiberglass using the countersink tool by hand. Then I cleco’d the tip back on. This one is about ready to be riveted into place once and for all.

Categories: Fiberglass Tips

More Filling and Sanding Tips – 0.75 hr

May 17, 2010 Leave a comment

Monday May 17, 2010

Tonight I had a little time so I sanded the leading surface of the rudder tip flush with the counterweight skin. This West System filler material sands and shapes easily. The shape is almost perfect with just a few minor pin holes and one small dent that I will fill later.

I also sanded out the leading end of the left elevator tip. The black tape is to prevent scratching up the skin. The shape here is also very good. I’m happy with it.

Categories: Fiberglass Tips

Filling and Sanding Tips – 4 hrs

May 17, 2010 Leave a comment

Sunday 16 May, 2010

The left elevator tip shape was pretty good for a first cut, but it needed some reinforcement (it was thin) and filling. I did some additional sanding and removed some additional gel coat on the outside to increase the overlap area.

Then I applied another layer of fiberglass on the outside. Since I had excess epoxy left over I mixed in some West Systems filler to thicken it to a line peanut butter consistency and laid on a layer on top. This was actually not a good idea because it made the underlying fiberglass move around a bit so I won’t do this again. But once I started I was committed. Here is how it looked.

I also applied a thick layer to the end of the rudder tip because it is shorter than the rudder and I want to sand it down flush.

After the epoxy cured I sanded the elevator tip smooth and flush with the gel coat. It actually turned out well in spite of my mistakes.

The tips of the horizontal stabilizer have to be cut to size and the open face needs to be closed out with fiberglass and filler. With the left elevator installed for reference, I trimmed enough off the left HS tip to leave about 1/8 inch clearance to the tip of the elevator. Then I cut a piece of Last-a-Foam to fit the inside of the tip, spreading the sides just enough to make it fit the opening in the HS snugly. Then I applied two layers of  Rutan bidirectional glass fiber with West Systems epoxy to the outside face of the foam. The fiberglass wanted to lift up away from the foam along the edges so I put some additional foam pieces on the outside to press the fiberglass down against the foam. I put my small electric heater in front of this to accelerate the cure.

Then I bonded another set of aluminum strips to the inside of the right elevator tip to reinforce the rivet grip. I do this in stages because I only have enough cleco clamps to do one strip at a time.

About four hours after laying up the first HS tip it was pretty well cured. The warmth of the heater really does accelerate the cure. I used a sanding drum on the rotary tool to remove the extra pieces of foam. It cut right through them like butter. Next step will be to reinforce the fiberglass along the joints to the tip on the inside.

Categories: Fiberglass Tips