Uh….yeah, so we’re building this all-metal monoplane….and we just spent a marathon day covered in clay, resin and glass!
When I last tried to make a gear intersection fairing from scratch, it was for my RV-8 back in 2005. The experiment ended with a mess tossed in the trash and a phone call to Bob Snedecker at Fairings-Etc for a set of his nicely-built intersections. When Louise’s -6 needed all new pants and fairings, we went with Bob’s work again – no use dredging up painful memories I figured. Well, one thing about building an RV-3 is that it makes you confront your fears! We really had no choice but to roll our own – no one makes fairings to fit this “rarest of all” model, and even if they did, they probably wouldn’t fit – I am convinced that no two RV-3’s are exactly the same shape.
All in all, the experience was, well maybe not “fun”, but it was satisfying to turn out a nice set of fairings (albeit still not finished for paint) in about 24 hours. We started with the pants and gear leg fairings in place, then pulled out a brick of clay from the local art supply house. Having mounted two sets of fairings before, I had a pretty good feel for how these should go, and how I like to mount them. There is a lot of variations that work – fully removable lowers, lowers split in the back, etc. I like the lowers glassed on to the pants, with a split between front and back. An overlap from the front piece fairs over the rear piece for a nice fit. I like to make the uppers with as few screws as possible, and the shape of the tunnel sidewalls on the -3 make it really slick – impossible to describe, and hard to photograph – take my word for it, if you’re building one, you’ll get the idea. The end product almost “clicks” in place, and two screws into nut-plates on the cowl are all that is needed to hold them in place.
Before we plastered on the clay, we used 2” wide vinyl electrical bundling tape to cover everything that we didn’t want to get messy. The clay was applied to this, and sculpted mostly with fingers. As a trained Aeronautical Engineer, I looked at the shapes we were making and asked myself “if I were an air molecule, would I be relaxed and undisturbed going around those body?” Long bodies are better than short bodies, and radical changes in direction get the molecules all excited, and we want them to be calm….
Satisfied with the shape, I decided we’d try to go with over-taping the clay, and I didn’t thing we could get the tape on the clay without wrinkles, bunching, and messing up the clay. Instead, we just waxed everything and laid up 4 layers of BID glass. It took quite awhile, alternating layers top and bottom on each fairing, but it really helped to have two people – one prepping and saturating the pieces, the other applying them. I didn’t check the clock, but we did break for dinner between the uppers and lowers! We used West Systems slow hardener to give us a reasonable working time, and that meant we had to let the layups cure overnight.
The next morning it took about an hour to pry everything loose. We cut the uppers with a vertical cut on the inside of the strut, and the lowers were split into a front and back half. Before removing the lowers, we drilled two cleco locating holes through the front and back halves so that we could get them in the same places on the wheel pants. Edges were trimmed, and then we proceeded to bond the lowers on to the pants sections (front and back). We’ll sand and blend the joints, then it is standard finishing before going to paint. The uppers will just take a couple of screws and nut plates (as mentioned), and again, standard finishing before going to paint (which will come after Phase 1).
Uppers Molded in place with clay still underneath:
Lowers – they are actually smoother than they look in this picture!
Gray Vinyl tape covered everyplace the fiberglass was laid up to allow easy separation:
Untrimmed fairing pieces removed and, the clay wadded up for a future project:
Lower fairing pieces ready to glass on to the pants:
Two days in the shop from “nothing” to molded shapes attached for flight. This is a perfect illustration of my love/hate relationship with “plastic” – I love what you can do with it, but hate the mess of layups and cleanup. Then again, the thought of making these fairings out of aluminum? Terrifying…..
Paul
When I last tried to make a gear intersection fairing from scratch, it was for my RV-8 back in 2005. The experiment ended with a mess tossed in the trash and a phone call to Bob Snedecker at Fairings-Etc for a set of his nicely-built intersections. When Louise’s -6 needed all new pants and fairings, we went with Bob’s work again – no use dredging up painful memories I figured. Well, one thing about building an RV-3 is that it makes you confront your fears! We really had no choice but to roll our own – no one makes fairings to fit this “rarest of all” model, and even if they did, they probably wouldn’t fit – I am convinced that no two RV-3’s are exactly the same shape.
All in all, the experience was, well maybe not “fun”, but it was satisfying to turn out a nice set of fairings (albeit still not finished for paint) in about 24 hours. We started with the pants and gear leg fairings in place, then pulled out a brick of clay from the local art supply house. Having mounted two sets of fairings before, I had a pretty good feel for how these should go, and how I like to mount them. There is a lot of variations that work – fully removable lowers, lowers split in the back, etc. I like the lowers glassed on to the pants, with a split between front and back. An overlap from the front piece fairs over the rear piece for a nice fit. I like to make the uppers with as few screws as possible, and the shape of the tunnel sidewalls on the -3 make it really slick – impossible to describe, and hard to photograph – take my word for it, if you’re building one, you’ll get the idea. The end product almost “clicks” in place, and two screws into nut-plates on the cowl are all that is needed to hold them in place.
Before we plastered on the clay, we used 2” wide vinyl electrical bundling tape to cover everything that we didn’t want to get messy. The clay was applied to this, and sculpted mostly with fingers. As a trained Aeronautical Engineer, I looked at the shapes we were making and asked myself “if I were an air molecule, would I be relaxed and undisturbed going around those body?” Long bodies are better than short bodies, and radical changes in direction get the molecules all excited, and we want them to be calm….
Satisfied with the shape, I decided we’d try to go with over-taping the clay, and I didn’t thing we could get the tape on the clay without wrinkles, bunching, and messing up the clay. Instead, we just waxed everything and laid up 4 layers of BID glass. It took quite awhile, alternating layers top and bottom on each fairing, but it really helped to have two people – one prepping and saturating the pieces, the other applying them. I didn’t check the clock, but we did break for dinner between the uppers and lowers! We used West Systems slow hardener to give us a reasonable working time, and that meant we had to let the layups cure overnight.
The next morning it took about an hour to pry everything loose. We cut the uppers with a vertical cut on the inside of the strut, and the lowers were split into a front and back half. Before removing the lowers, we drilled two cleco locating holes through the front and back halves so that we could get them in the same places on the wheel pants. Edges were trimmed, and then we proceeded to bond the lowers on to the pants sections (front and back). We’ll sand and blend the joints, then it is standard finishing before going to paint. The uppers will just take a couple of screws and nut plates (as mentioned), and again, standard finishing before going to paint (which will come after Phase 1).
Uppers Molded in place with clay still underneath:
Lowers – they are actually smoother than they look in this picture!
Gray Vinyl tape covered everyplace the fiberglass was laid up to allow easy separation:
Untrimmed fairing pieces removed and, the clay wadded up for a future project:
Lower fairing pieces ready to glass on to the pants:
Two days in the shop from “nothing” to molded shapes attached for flight. This is a perfect illustration of my love/hate relationship with “plastic” – I love what you can do with it, but hate the mess of layups and cleanup. Then again, the thought of making these fairings out of aluminum? Terrifying…..
Paul
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