Double Eagle Build DE-69
Paul Radford – Gold Coast Australia
Monday, October 20, 2014
I am at the point having build my ribs that I am about to launch into the manufacture of the nose ribs. I understand the trusted method of making these is by cutting the blanks and then shaping them with flush trimming bit on the router using an aluminium template, and then boring the lightening holes.
However the other day I was at a factory behind ours as we have been subcontracted to do some work with a graphic design firm. We have a small window furnishings business and can handle fabric jobs of various shapes and sizes.
They required us to help manufacture some fabric sample books for a large manufacturer of luxury yachts based here on the Gold Coast, Australia
When I was on a visit to their factory I could not help spying some of the interesting work they had produced in 3D using all types of base materials and asked how this had been achieved. The answer was simple and surprising, a flatbed CNC Laser cutter. After a tour of the facility, I had a light bulb moment and asked if the machine could cut ¼ inch Birch plywood. Yes was the answer. You can see where this is going.
I showed them my plans to the DE and asked would it be possible to cut the nose ribs this way from a sheet of plywood. Easy, was the answer. The machine should be able to cut all the ribs from one 1200mm X 120mm (4 X 4 feet) sheet of ply. This would also include all the lightning holes and notch for the nose rib stringer.
Excited by the answer I suddenly found myself in a quandary and started to question myself. Should I do this? Is this in the spirit of the build? Would this method be frowned upon by others? Then I thought about it this way. This is an experimental category aircraft so experiments (properly guided and thought through) are OK. I have always enjoyed looking for other solutions and ways to apply technology to an idea. I spoke to a few who had differing opinions but no one canned the idea. So I am going to proceed and explore this option.
I will write a more detailed article and do a small video for this interested in following what i am doing. we have already run some tests and cut a sample rib in MDF (4mm) from a first attempt at tracing the original drawing in Sketchup. This came out well (in 35 seconds). The only issue is that the laser cutter leaves a distinctive burn mark around the edge of the timber, however this can be easily sanded back. This was my only major concern at this stage as i do not want this to effect the glue adherence.
I will post some more information as it comes to hand. In the mean time i have attached a couple of images of the drawings and sample Rib in mdf
cheers Paul
