CR26I naming for the composite fuel cell.
Same construction as the carbon fiber cell: 1 layer of Kevlar over 5 layers of stitched carbon twill. See the Carbon Fiber Fuel Cell entry.
No part-specific design process is documented. The Fuel subsystem design process applies: 1. Set tank volume from endurance consumption plus margin, with the HydraMat area and the tank CG as constraints. CR26: 1.4 gal cell, 1.56 gal effective system. 2. Design the sump to the acceleration cases: 1.42 g at 45 deg from vertical under acceleration against a rear wall 30 deg from vertical, and 2.51 g at 66.5 deg from vertical under braking against a vertical front wall. 3. Lay up the sump: 1 layer of Kevlar over 5 layers of stitched carbon twill on HIPS dissolvable molds, bonded with 3M DP420, sealed with Caswell epoxy gas tank sealer. 4. Design the top plate: -4 AN weld bungs instead of fittings, stud bulkhead terminals so no fuel path runs through wire, an aluminium terminal block for proper bulkhead seating. 5. Leak test the assembled system before it goes in the car.
See the Carbon Fiber Fuel Cell page. Three CR26I Fault Vault entries: fuel cuts under lateral load at low fuel level (HydraMat too high, fixed by lowering it and rewiring), top hat threads stripping from overtorque and repeated assembly until the tank leaked after endurance, and an undersized fuel vent check valve that let tank pressure build until unscrewing the top sprayed fuel over people and the car.
Dimensions called out on the cost report drawings. These are the figures printed on the drawing, not a labelled specification; open the drawing itself for what each one refers to. CR26 Fuel Cell + Standoff (mm): 136.1, 396.9, 99.3, 185.4, 115.9 Source: Cost report drawings: CR26i/Powertrain - IC/Design/Y - Cost Report Drawings/Fuel/CR26 Fuel Cell + Standoff.pdf; CR27i/.Powertrain/Design/Y - Cost Report Drawings/Fuel/Archive/CR26 Fuel Cell + Standoff.pdf Quantity per car, as costed: 1
Nothing in CrimsonStorage covers these yet.