1. Stave #12 This stave core was built together with William Emmet, Tom Hurteau, and Jeffery Ashenfelter from Yale University in the week of 16-20 November 2015 1

2. Stave#12 core assembly production program Day1: (Monday 16 th November) – Glue lower foam blocks, lower half Z=1.3m end closeout and Z=0 end closeout to the face sheet (axial tape#18); – Glue flex circuit tape to the cooling pipe and test it; Day2: (Tuesday 17 th November) – Glue Z=1.3m end upper half closeout, cooling pipe with flex circuit tape and upper foam blocks; Day3: (Wednesday 18 th November) – Glue CF channel side closeouts; Day4: (Thursday 19 th November) – Glue honeycomb core, in-core housings, z=0 mid-end support; Day5: (Friday 20 th November) – Mill the stave core to the nominal thickness; – Glue the top face sheet (stereo tape #21); 2

3. Tooling used are: – Base jig (CF vacuum jig); – Masking ruler; – Foam block alignment jig; Stave core material: – Co-cured face sheet (axial tape #0018); – Lower foam blocks; – Lower half Z=1.3m end closeout; – Z=0 end closeout; Procedures – Masking steps – Foam block alignment setup – Etc. Day1: (Monday 16 th November) In addition: Glued thermistor flexi circuit tape to the cooling pipe (#4) at EOS region, and tested resistance of NTC. Observations and remarks:  Material thickness and tooling precisions need to be checked carefully beforehand;  When dry fit the foam blocks to the alignment jig, the foam blocks thickness and groves were less perfect – not well levelled. However the setup procedure should improve the levelling of the foam blocks and for this reason, it is very important to follow the setup procedure when mounting the foam blocks to the jig;  Thermistor flexi circuit tape needs to be glued to the EOS cooling pipe and test resistance of NTC before building into the stave core. This was first time we did it, and a proper tooling will be developed for this process in future. 3

4. Tooling used are: – Base jig (CF vacuum jig); – Z=1.3m end upper closeout clamp – Glue applicator Stave core material: – Upper foam blocks; – Upper half Z=1.3m end closeout; – Cooling pipe (#4) with flex circuit tape glued on Procedures – Glue applied to the pipe – Etc. Day2: (Tuesday 17 th November) Observations and remarks:  The tooling (glue applicator) used to apply the glue to the pipe will need to be modified to improve the gluing application as the current tooling made the process very messy;  Cooling tubes were too long. As a result, the local modifications of the PEEK end closeouts were needed to allow the cooling pipe assembly to come through.  We discussed that the cooling pipe and foam blocks gluing could be done as a separate parallel operation which could save production time.  worth presuming! Dry fit cooling pipe 4

5. Day3: (Wednesday 18 th November) Tooling used are: – C channel placement jig Stave core material: – CF C channels 4 pieces of CF C channels with various length (1277mm, 1187mm, 100mm, and 49.5mm); The longest piece needs rectangular slots to be machined; The shortest piece needs to cut a slit at one end. Procedures – CF C channels assembly Stave #10 pictures Observations and remarks:  When C channels are assembled to the jig, one must check the height difference between the datum face of the jig (the interface to the face sheet) and the face of the side clamping pieces (interface to the stave building base jig), to make sure that they are consistent (i.e. 0.3mm+0.05 which is the thickness of the face sheet).  It is important to dry fit the C channel assembly jig onto the stave core to check for any potential clashes before applying glue. 5

6. SLHC Day4: (Thursday 19 th November) Tooling used are: – Base jig (CF vacuum jig); – C channel side clamping pieces; – In-core housing location jig; – Z=0 mid-end support locator; – Glue bath (~0.5mm deep); Stave core material: – Trimmed to sized CF Honeycomb – In-core housings (PEEK); – Z=0 mid-end support (PEEK); Procedures Observations and remarks:  When tailoring the honeycombs, one should try to fit them loosely into the gaps, as the CF honeycombs are “springy” and any spring back pressure exerted on the adjacent foam block could cause can cause damage to the foam;  Lay a rubber layer on top of the core during the glue curing before adding the weighs on. This helps the load to even out on the uneven surfaces. 6

7. SLHC Day5: (Friday 20 th November) Tooling used are: – Base jig – Glue bath – Masking ruler – C channel side clamping pieces Stave core material: – Stereo tape co-cured face sheet (tape#22) Procedures – Mill the core to size; – Normal Hysol filled to the glue bath; – BN loaded Hysol applied to the facesheet; Stave core was milled to the nominal thickness in the morning Top face sheet was glued on in the afternoon Observations and remarks: After the stave core has been milled to the normal thickness, one must use a straight ruler to check the honeycomb core height across the whole area, in case of any local undersized area in the honeycomb core. 7

8. Nearly completed Stave#12 core SLHC Things to do to next are: Trim the 10mm sacrificial edges off, apart from the two ends; Glue the locking points; 8

9. Completed Stave#12 SLHC9

10. Imperfections SLHC  Local delamination Honeycomb not being glued well to the face sheet at this region. This could be caused by a local region of honeycomb thickness being undersized.  Carbon dust contamination Electrical feature of the tape needs to be protected during the stave production 10

11. Summary Oxford and Yale worked together to build Stave #12, using a set of stave tooling and assembly procedures. The 5 days stave production program reflected the real production time needed to build a stave. Production time could be reduced by carrying out the foam blocks and cooling pipe gluing as a subassembly, away from the stave core production. During the stave production, there are stages that additional machining is needed, this risks potential damage to the stave core, for example, the surface of the face sheet could get scratched, the carbon dust can easily contaminate the tape, and any accidental damages caused by transporting stave core from Lab to WS etc. Carefulness could minimise this risk, but a proper procedure will be beneficial to prevent these from happening. A full set of Stave core assembly tooling are made and ready for shipping to Yale (waiting for the shipping box to be delivered). 11