Belatedly I’m writing up our weekend spent de-burring, priming, dimpling and prepping the large fuselage floor skin – it was a lot of work but it went quicker than expected due to some unexpected help from a lovely friend!
J and I had a full house of guests in the middle weeks of Jan and we spent any downtime getting the holes and sides of the skin deburred and scuffing it ready for priming. We also had to wash and rinse it, which necessitated J putting on full waterproofs (a mixture of his kayaking and wet-weather hiking kit) and me getting to spray him and the skin with a cold hose…all for a good cause, of course!
Once our guests had departed (y’know, because spraying toxic chemicals around can perhaps seem unwelcoming…) J then shot the primer and we quickly prepped the stiffeners, doublers and nut plates.
We’d invited our friend Bill round for a long overdue catch-up and spent a couple of hours drinking tea and chatting about flying. We showed him our progress with the build and he and J got into lengthy discussions about electrical supply systems before we decided to get on with dimpling the floor skin.
Bill is building a fibreglass Europa at the moment so he’s been through a similar process, although he’s a lot further on than us! It’s been an unexpected and wonderful surprise to find so many kit aircraft builders and owners in Scotland, and there are several others based with us at Oban airport.
The floor skin is the single largest piece we’ve worked on so far, and before it was dimpled it was very flimsy and prone to bending and sagging in the middle. It was a great help to have three people supporting it whilst we worked on the dimples.
There were a LOT of dimples to do, and once again we thanked the universe for the DRDT-2 dimpling tool, without which a number of people we know have said they wouldn’t contemplate building an RV. We definitely agree! It is so much quicker and more consistent than the other methods of dimpling.
We are also late but enthusiastic adopters of a laser attachment to the DRDT-2 tool, an idea we read about on the Van’s forum. You can set up a laser pointer with two intersecting lines, which helps you sight the dimple die when working on large pieces like this and avoids the scratching that inevitably results from trying to guess and getting it wrong! Definitely worth the initial faff of getting it set up and calibrated.
Bill was amazing and stayed in position for over two hours helping us support the skin and finish off the dimpling. It’s no exaggeration to say it probably took half the time with three people than it would have done with two. THANK YOU Bill and let us know when we can return the favour in fibreglass!
There was one single pesky hole in the middle that the DRDT-2 couldn’t reach (we think we tried every angle, but if any -14 builders have actually managed it, let us know!!) so we used a pop dimple die and the pop rivet tool to deal with that one.
Dimples done, we set about positioning and riveting the series of stiffeners and doublers which go onto the floor skin before the rib assembly begins:
J came up with a neat little trick to help us with back riveting on this large and flexible skin – he cut out a section of a yoga mat and set the back riveting plate inside, so the surface was level and we weren’t at risk of putting a bend in the skin. As an aside, we use LOADS of yoga mats on the build – they are fab for covering benches and protecting the pieces from damage!
Next we needed to get a large pile of ribs and spars assembled and attached…see next post.