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Flagship Project

Bipropellant Liquid Igniter

Four attempts across two years to build a working N₂O/methanol torch igniter — the fifth finally crackled to life.

IgniterBipropellantICLRNitrous
I proposed building a liquid igniter to the ICLR leads and they were incredibly supportive. It took five prototypes across two years to get it to work reliably.

The Journey

  1. V1 — 20 g/s N₂O, 5.8 g/s methanol, impinging orifices in 316L stainless. Stainless was horrible for machining. Likely failed due to high mass flow.
  2. V2 — Smaller orifices (0.5 mm N₂O, 0.2 mm methanol) in aluminium. Nitrous frosted and clogged both orifices. Gave up after a long hard night.
  3. V3 — Led freshers to design multiple orifice sizes. Low O/F ratio prevented sustained ignition.
  4. V4 — Coaxial shear design with a 0.2 mm ID / 0.5 mm OD needle epoxied into a 0.9 mm hole. Tested with gaseous N₂O, propane and IPA. First flames!
  5. V5 — Smaller version of V4, tested with liquid N₂O and IPA. Worked beautifully.