# L29 Pre-flight **Block 3: IR EW and Signature Management — Lesson 29: Project 3 Work Day** *Work this before L29. Pre-flights are never collected — in class, anyone may be cold-called to present any question at the board, and that recitation is the participation grade.* --- ## Assumed pre-class reading - The Project 3 handout (B-21 IR/RCS Signature Trade Study), posted with `B21_SignaturePattern.csv`, `SignatureMenu.csv`, and `L29_Project3Starter.m`. - The L28 wrap-up (the loudest-band fusion rule). This quiz checks that you arrive ready to work, not that you have done the project. Read the handout and skim the starter before class. --- ## Quiz questions (5 items, ~5 minutes) **Q1.** (Multiple choice) In Project 3, the product your group must deliver is: - [ ] (a) A single new stealth coating that beats every threat - [ ] (b) A prioritized package of signature investments, chosen within a fixed budget, that minimizes the aircraft's detection range - [ ] (c) A flight route that avoids all three threats - [ ] (d) The exact RCS of the B-21 at every aspect --- **Q2.** (Multiple choice) Detection across the three threats obeys the loudest-band rule $R_{\text{det}} = \max_b R_b$. To reduce $R_{\text{det}}$, an investment must: - [ ] (a) Reduce any band at all — they all help equally - [ ] (b) Reduce the band that is currently the limiter (the longest-range threat) - [ ] (c) Reduce the quietest band first - [ ] (d) Increase the aircraft's speed --- **Q3.** (Multiple choice) The scenario has three threats: a VHF surveillance radar, an X-band fire-control radar, and an IR MANPADS. At the baseline signature, which one is the **loudest band** (sets $R_{\text{det}}$)? - [ ] (a) The IR MANPADS, because IR is always the hardest to hide - [ ] (b) The VHF surveillance radar, at about 90 km — and shaping/RAM barely help at VHF - [ ] (c) The X-band fire-control radar, at about 45 km - [ ] (d) They are all equal at baseline --- **Q4.** (Short answer) Project 3 has a built-in budget tension. In one or two sentences, explain why you cannot simply buy the cheapest signature treatments and why the loudest threat is hard to address. --- **Q5.** (Multiple choice) The starter script `L29_Project3Starter.m`: - [ ] (a) Already contains the optimal package — just read it off - [ ] (b) Scores one example package (X-band RAM + plume) that leaves you found at ~85 km, so you must design a better package within the same budget - [ ] (c) Computes nothing; it is only a plotting template - [ ] (d) Requires the true threat positions, which are hidden