Pieter Visser's X350

[Pieter001]

I did the strengthening of the rudder attach points today, as well as cutting carbon for the elevator pulley bracket and the aileron bell crank brackets.

For the rudder attachment points I decided to use 5 layers 300gr bi-ax carbon for the upper and lower area and finished the job with peel ply. To ensure that the parts cure at the correct angle, I put packaging tape over the peel ply and then fit the LH fin skin. I've already done the trail fit a couple of days ago when I glued on the RH fin skin.

The carbon is a great product to work with, I love it! I opt to wet out the piece of cut cloth on a piece of paper (much like wax paper) on both sides and then to place it in position, using a brush to "stab" it into all the corners and areas. I also use a little composite roller tool every couple of layers to roll out any air bubbles there may be, as well as excess resin. The excess resin can only be rolled out by rolling in one direction to the outer edge of the carbon cloth and by applying a good bit of pressure. I do the same once I've applied and smoothed the peel ply. The result I get using this method is fantastic in my opinion, but I'm not an expert by any means.

One learns a lot of things building your Whisper, not only about composites, resins and tools, but also about one self

bottom rudder attach point - 5 layers carbon 300gr bi-axial complete with peel ply

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top rudder attach point - 5 layers carbon 300gr bi-axial complete with peel ply

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made a template for elevator pulley hole and drilled the corners

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[Pieter001]

Packaging tape over wet resin to fit RH fin skin

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RH fin skin fitted for the cure using screws

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[Pieter001]

Glued the bronze wing pin bushes onto the rear spar plank, so not a big work day, but at least something was done

The flange areas of the bushings are put against each other for this clamp and cure to put pressure on the busing when the planks are clamped. The front plank and bushings was already glued earlier, so the areas and wing bolts were waxed up proper to ensure that nothing gets stuck together that should not be.

PS: The best course of action here is to glue the bushes with the entire assembly set. Doing it the way I did here resulted in my bush being off by around 0.8mm, which is not too much, but a pain to get the wing bolt through all the bushes now

Leveled the planks and clamped them to cure

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The wing bolts have to be level too

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[Pieter001]

Made hard board templates for the aileron bell crank and the rudder pulley. Then cut a section of polystyrene for the pulley bracket and made a carbon layup: 11 layers 300gr bi-ax carbon.

Before the 12th layer, the resin started gelling, so I stopped on 11, but this is one SERIOUS layup! Rolled out the excess resin, using a roller occasionally and after I applied the last layer of peel ply (started with a layer of peel too).

I believe 11 will be sufficient, I have no doubt! Carbon is generally 2x the strength of E glass, so this bracket is going to be a beast!

Polystyrene pulley bracket template cut and lines indicate where the layup is to go

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11 layers carbon 300gr bi-ax finished with peel ply and air- and excess resin rolled out

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[Pieter001]

This morning I handed in the bronze wing bolt bushings to be shortened, both to a length of 101mm. I should be able to pick them up sometime this week, which means I will start cutting glass to do the layups of the carry through spar

Not done much else... did extend the cut lines of the elevator pulley bracket, which I still need to cut and then start shaping and cutting the final 2 brackets.

PS: Bronze bushing was cut to 103, after I read rather too than too short, but turns out they are indeed 2mm too long now Lesson is to trust your measurements, so I live and learn. I am considering trimming then down, but that will take another week and R230 per bush NZ is really expensive compared to SA. I may just grin and bear, or buy a lathe!

[Pieter001]

Setup the angle grinder with a 1mm steel disk on the workbench at the correct height to cut the elevator pulley on the silver cut lines I've drawn. Once this was done, I removed the foam and pulled off the bottom layer of peel ply to get the part material free.
The general rule of thumb for 300-400gr bi-ax is 0.5mm for each layer. The material thickness measures 5.6mm for the 11 layers

Clamping the angle grinder at the correct height to make straight cuts

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Foam and bottom peel ply removed with the vernier showing the material thickness

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[Pieter001]

To make the elevator bracket the simplest way was to take the bracket drawing and to get it resized to the correct scale through trial and error. Then cut the out the template, which I changed slightly to make it simpler and it will add a bit more strength where the alu parts did show hairline cracks. This carbon part is already over engineered, but the cutting is going to be simpler too.
Then rough cut the two parts with the angle grinder. The template was used to mark the drill holes, which I drilled into one part, making sure the pulley and pins won't foul. I then lined up the parts back to back and clamped them together to drill the holes into the second part. Only 4mm drill bit used for this. Now all that is left is to sand the parts on the belt sander while bolted together.

Correctly scaled drawing to cut paper template to transfer onto the carbon sections

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Drilled holes from template and transferred to both parts while clamped and now bolted together for final sanding

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[Pieter001]

Done the shaping Now need the AN5 bolts to complete this job. I will need a slightly longer bolt as my layup is thicket, so AN5-22 should work well.

[Pieter001]

Set the wings up with zero incidence and correct dihedral and then glued in the wing spar bushes. All well but I found that there is slight misalignment on the rear spar plank and it takes quite a bit of force to get the wing bolts in.
Overall I'm happy with the result and the 103mm turned out to be exactly what was needed, so no need for more machining
I fabricated 5.5mm carbon spacers to take up the space the shorter bushes left. These will be glued in later.

Wing spar bushes curing

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Carbon fiber spaces to make up for wing spar bushes which are now shorter

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[Pieter001]

Removed the peel ply from the spar planks and sanded the areas to bond for the spar box. I then checked the alignment with the laser and fabricated the foam spacers for the spar box layup, which I put in place with packaging tape and also added added a flox bead in the corners.
I won't have time to do the layup today, but I've cut the 4x410gr bi-ax E glass and will get to work in the morning to do the layups.

Laser for alignment is GREAT - 2 used - 1 for incidence and one for alignment

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foam spacers with packaging tape before flox

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Flox bead in the corner - this "wall" area on the planks I'll have to sand before the layup is done

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