# Acceptance Criteria Assessment

## Acceptance Criteria

| Criterion | Our Values | Researched Values | Cost/Timeline Impact | Status |
|-----------|-----------|-------------------|---------------------|--------|
| Flight duration | "Maximizing" (undefined) | 2-4 hours for electric fixed-wing in 5-15 kg MTOW class (Albatross: 4h, Vulture: 3.5-5h) | Higher endurance = larger battery + lighter frame = higher cost | Added — suggest target: ≥3 hours |
| Payload capacity | 1.47 kg fixed | 1.47 kg is modest; benchmark platforms carry 4-8 kg in this class | Low payload relative to class = more weight budget for battery/fuel | Modified — no change needed, favorable constraint |
| Frame weight | Not specified | Benchmark: 3.0-4.0 kg bare airframe for 3m wingspan class (Albatross: 3.35 kg) | Lighter frame = more battery weight = longer flight | Added — suggest target: ≤3.5 kg bare airframe |
| MTOW | Not specified | 8-15 kg typical for this class | Drives wing sizing, motor selection, battery capacity | Added — suggest target: 8-12 kg |
| Cruise speed | Not specified | 15-25 m/s typical for recon fixed-wing (Albatross: 19 m/s) | Slower cruise = longer endurance but less area coverage | Added — suggest target: 15-20 m/s |
| Wingspan | Not specified | 2.5-3.5m for this MTOW class | Larger span = better L/D = longer endurance, but transport/handling harder | Added — suggest: 2.5-3.5m |
| Battery energy density | Semi-solid state interest | 300-350 Wh/kg (semi-solid, 2025-2026 commercial products) vs 180-250 Wh/kg (LiPo) | Semi-solid ~2-3x cost of LiPo but 30% more flight time | Added — suggest: ≥300 Wh/kg (semi-solid) |
| Budget | $100k total | Sufficient for custom composite airframe + avionics + batteries + ground station | $100k is generous for single prototype in this class | Modified — no change needed |
| Operating temperature | Not specified | -20°C to 45°C is standard for commercial UAVs | Affects battery performance and material selection | Added — suggest: -10°C to 45°C |
| Wind resistance | Not specified | 10-15 m/s sustained for fixed-wing recon | Affects structural requirements and endurance | Added — suggest: up to 12 m/s sustained |

## Restrictions Assessment

| Restriction | Our Values | Researched Values | Cost/Timeline Impact | Status |
|-------------|-----------|-------------------|---------------------|--------|
| Budget | $100k | Ample for 1 prototype. Carbon fiber airframe: $5-15k (custom tooling + manufacturing). Batteries: $2-5k. Avionics: $3-5k. Motor/prop/ESC: $1-2k. Ground station + comms: $5-10k. Integration + testing: $10-20k. | Well within range | Modified — no change needed |
| Manufacturing access | None specified | Carbon fiber requires either outsourcing (CNC + layup vendors available globally) or basic workshop with vacuum bagging setup (~$2-5k investment) | Outsourcing is viable within budget; no blocker | Added — outsource recommended |
| Regulatory | None specified | Sub-25 kg in most jurisdictions requires registration + remote pilot license. No specific material restrictions. | Minimal impact at this MTOW class | Added — follow local UAS regulations |
| Payload (fixed) | 1.47 kg | Non-negotiable — mission equipment | No change | Added |
| Frame material | Open investigation | Research strongly favors carbon fiber composite (CFRP) with foam-core sandwich construction | Drives the core research question | Added |

## Key Findings

1. **Flight duration target of ≥3 hours is realistic** for an electric fixed-wing in this class with semi-solid batteries. The Albatross achieves 4 hours with LiPo; semi-solid batteries would extend this further.

2. **1.47 kg payload is light for this class** — leaves substantial weight budget for batteries, which directly translates to longer flight time. This is a favorable constraint.

3. **Semi-solid state batteries (300-350 Wh/kg) are commercially available now** from multiple vendors (Grepow, Tattu, Herewin). They offer 30% more flight time than LiPo at 2-3x cost per Wh but with 4-6x cycle life, making TCO favorable.

4. **$100k budget is generous** for a single prototype in this class. Typical custom composite UAV builds in this class cost $30-60k for first prototype including all subsystems.

5. **Carbon fiber composite is the clear frontrunner** for frame material based on weight-to-stiffness ratio, which is the primary driver for endurance.

## Sources
- Source #1-#12 (see source registry)
