L29 Pre-flight

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) One broadband coating chosen to buy down all three threat bands at once

  • [ ] (b) A prioritized package of signature investments, within budget, that minimizes detection range

  • [ ] (c) A flight route and timing plan that keeps the aircraft outside all three threats’ detection rings

  • [ ] (d) A measured RCS table for the B-21 at every aspect and frequency

Q2. (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, at about 6 km, because IR is the hardest band to hide

  • [ ] (b) The VHF surveillance radar, at about 90 km against the baseline RCS

  • [ ] (c) The X-band fire-control radar, at about 46 km, where broadband RAM pays off

  • [ ] (d) They are all equal at baseline, by design of the threat mix

Q3. (Multiple choice) Menu item F (DIRCM) carries no dB entry in any band — the starter simply drives the MANPADS range to zero when you buy it. Under \(R_{\text{det}} = \max_b R_b\) with the VHF radar at 90 km, what does buying DIRCM alone do to \(R_{\text{det}}\)?

  • [ ] (a) Raises it, because the DIRCM’s own laser is an emission the defender can home on

  • [ ] (b) Nothing — it takes the 6 km IR range to 0, but VHF still limits at 90 km

  • [ ] (c) Halves it, because removing one of the three threats halves the union

  • [ ] (d) Drives it to 0, because a defeated terminal threat cannot complete the kill chain

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 within the budget, so the trade study is reading it off

  • [ ] (b) Scores one example package (X-band RAM + plume) that still leaves you found at ~85 km

  • [ ] (c) Only plots the aspect pattern; every range calculation is left for you to write

  • [ ] (d) Needs the threats’ true positions, which the handout deliberately withholds

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