8.11.5-10 Bending Longerons

Helpfully, Vans provide a full scale template of the curve/bend required and suggest making a cardboard template for accuracy. To be honest, I’ve never had much joy with the accuracy of cardboard templates but luckily I had a bit of 4mm plywood lying around so I decided to use that instead. I cut out the paper template and stuck it to the plywood. Then, using a stanley knife with new blade, I carefully followed the curve of the paper template. I repeated the cut numerous times until I cut through the plywood and had a nice template.

Earlier in the week a very kind RV builder offered to lend me their bending dies which involved a quick trip over to Wycombe airfield to collect them and swoon at their flying RV. With that in hand I felt quietly confident about getting these bends done.

The first problem I encountered however is that the longerons wouldn’t fit in the vise because various items on the workbench were in the way. I decided to relocate the vise to the portable workbench instead. Once there I then sat the dies in the vise but found that they would sink to the bottom of the vise and be tricky to keep in place. I popped a piece of wood below the dies and it was problem solved.

I then put the longerons in the dies in the vise and set about squeezing the vise until I could feel the dies touch the longerong and the felt it bend slightly. On first attempt it was clear I didn’t bend it enough. So on the second round I added another 1/4 turn of the vise handle. Unfortunately that was too much and I over bent the longeron. Not a problem as it is easily unbent by gripping it in the vise and unbending by hand. Eventually the bend matched the template perfectly.

Once the curve was bent it was time to do the sharp downward bend. This was a lot more draconian and involved clamping the longeron in the vise and whacking it with the mallet several times. Nothing too difficult though but it did make everything on the workbench ‘dance’! The last task was to twist the sharp bend so the end of the longeron was at 17 degrees. I used a large wrench to make the twist without any difficulty.

After lunch my wife joined me to help bend the right longeron. It is amazing how much easier (and more fun) it was with an extra pair of hands.

That’s two longerons bent! I’m not 100% confident that all the angles are perfect but it was pushing 30 degrees in the workshop and I was losing motivation fast. Time to stop for the day before I make a silly mistake. I popped them on the floor before I left to avoid any silly accidents overnight.

Not bad for a days work, but I think it does need another check.

8.11.1-4 Cut & mark longerons

I couldn’t put it off any longer, those longerons needed to by cut. I brought home another tape measure from work to make sure sure sure there was no mistake. I also recruited my son to come and double check the plans and the measurement marks.

While reading one of the builders blogs earlier in the week I noticed they had a small chop saw so I couldn’t resist and treated myself to one too. I am delighted I did, it arrived perfectly set up and cut through the longeron like butter. I’m very pleased with it.

Once cut I checked the measurement again…

I’m pleased with the cut, a bit of filing will trim that to perfection but I’ll wait until much later in the project to do that. Next I marked the longerons for left and right and forward too. Then I trimmed the aft ends of the longerons as per the plans.

Finally I marked the bend location along with marks at every inch to help with the bending process.

That’s all for today. I’ll do the bend another time.

8.11.1-2 Measure & mark longerons

The bulkhead parts are still drying so I can’t do any work on those today so I decided to locate the long angles that were shipped with the wings and dust them off. The instructions say to cut the longerons to exactly 173 7/16″. I measured the longerons and marked it then checked again with 2 different tape measures to be sure. I then left it at that for the night. There is no way I want to make a silly mistake on these as it would be a nightmare to get replacements.

8.9.2 + 8.10.1 Scuff & wash parts for priming

A long session today checking, scuffing and washing all the bulkhead parts before priming. When you see the mountainous pile of parts it takes some willpower to work through it all. I just put some good tunes on and settled into it for the day.

8.9.1 & 2 Match drill & debur F-711 Bulkhead

The past few bulkheads have been single parts but the F-711 bulkhead was a bit more complicated. I started by finding the two bulkheads and clecoing then together back to back. Next I found the aluminium bar and cut it down to length. I then marked a centre line on the bars and the lowest drill hole as per the plans. I drilled the bottom hole on each bar and then clecod it to the bulkhead assembly. Using the centre line I drew earlier I lined up the bars with the predrilled holes in the bulkhead and back drilled the remianing holes.

Once that was done I fabricated the to support angle but I wasn’t happy with my first attempt. I had cut it too short so I made another. The second attempt was much better. I clamped it in place and then back drilled that using the bulkhead and bars as guides.

Once that was all done I removed the cut out as per the instructions but forgot to take any pictures afterwards.

8.7.1-9 Drill, debur and prep F-706 bulkhead parts

Back at the bulkhead work today with yet another bulkhead to work on. Today it is F-706. I started by gathering all the parts needed and then deburring the sharp edges. One thing that struck me about this bulkhead is that it is super thin. I’m not too worried as I know that it is reinforced with a blanking plate that closes the entire hole. This particular bulkhead is the one that forms the back of the luggage area. In a larger plane it would be the back of the rear passenger seats but mine will be a two seater so this will be the baggage area instead.

You may have noticed the football on in the background, well it turns out watching England play in the World Cup from my workshop is good luck. It’s the first time I’ve ever watched them and they’ve won a match! And won spectacularly too, 6-1, nice! Anyways, while the football was on I was still working making parts from angles for the bulkhead. Like this F-729C bracket which had to be made from angle stock and then bent in the vise to 88.5 degrees. Boy am I glad Van’s supplied a scale drawing here.

After making the various extra parts I assembled the bulkhead and then match drilled all the holes as usual.

It looks so cool. The rectangular hole at the bottom is for the elevator push rod (which makes the plane go up and down!). Once everything was match drilled I disassembled everything and deburred the drilled holes and scuffed all the parts ready for priming.

That’s it, all the parts are ready to be washed for priming. I’ll do that when I’ve done more bulkheads so as to make the most of a priming session.

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