gps-denied-onboard/_standalone/UAV_frame_material/01_solution/solution_draft02.md

Solution Draft (Rev 02)

Revised Constraints (vs Draft 01)

Constraint	Draft 01	Draft 02
Cost per unit	$100k prototype	< $7k, target < $5k
Material	CFRP (T700)	S2 fiberglass (radio transparent)
Radio transparency	Not considered	Required — full RF transparency for GPS, telemetry, data links
Flight time	5-6 hours target	Same if possible, can be less
Transport	Not specified	Disassembled fits in car trunk; 2 planes per pickup truck

Product Solution Description

A modular, radio-transparent electric fixed-wing reconnaissance UAV built with S2 fiberglass/foam-core sandwich construction with internal carbon fiber spar reinforcement. Designed for field deployment — disassembles into 3 sections (2 wing panels + fuselage) that fit in a car trunk, with 2 complete aircraft fitting in a standard pickup truck bed. Powered by semi-solid state batteries for maximum endurance.

Target performance: 3.5-5 hours practical flight endurance, 9-10 kg MTOW, ~3m wingspan, < $5k BOM per unit.

┌──────────────────────────────────────────────────────────────┐
│                  MODULAR AIRFRAME LAYOUT                      │
│                                                              │
│   LEFT WING PANEL        FUSELAGE         RIGHT WING PANEL   │
│   (~1.5m span)          (~1.0-1.1m)       (~1.5m span)      │
│  ┌──────────────┐   ┌──────────────┐   ┌──────────────┐     │
│  │ S2 FG skin   │   │ S2 FG skin   │   │ S2 FG skin   │     │
│  │ PVC foam core│◄─►│ Battery bay  │◄─►│ PVC foam core│     │
│  │ CF spar cap  │   │ Payload bay  │   │ CF spar cap  │     │
│  │ (internal)   │   │ Motor+ESC    │   │ (internal)   │     │
│  └──────────────┘   └──────────────┘   └──────────────┘     │
│                                                              │
│  Wing-fuselage joint: aluminum spar joiner + 2 pin locks     │
│  Assembly time target: < 10 minutes                          │
│  Material: S2 fiberglass = RF transparent (GPS/telemetry OK) │
│  Internal CF spar: minimal RF impact (narrow linear element)  │
└──────────────────────────────────────────────────────────────┘

TRANSPORT CONFIGURATION (standard pickup truck, 6.5ft bed):
┌───────────────────────────────────────────┐
│  Truck bed: 198cm × 130cm (wheel wells)   │
│  ┌──────────────────┐ ┌────────────────┐  │
│  │ Plane 1 wings    │ │ Plane 2 wings  │  │
│  │ (2 × 150cm long) │ │ (2 × 150cm)    │  │
│  │ stacked ~20cm    │ │ stacked ~20cm  │  │
│  ├──────────────────┤ ├────────────────┤  │
│  │ Plane 1 fuselage │ │ Plane 2 fuse.  │  │
│  │ (~110cm)         │ │ (~110cm)       │  │
│  └──────────────────┘ └────────────────┘  │
│  Total width: ~60cm × 2 = 120cm < 130cm ✓│
│  Total length: 150cm < 198cm ✓            │
└───────────────────────────────────────────┘

Existing/Competitor Solutions Analysis

Platform	MTOW	Endurance	Payload	Material	RF Transparent	Modular	Price
Albatross (kit)	10 kg	4 hours	4.5 kg	Fiberglass + CF	Partial	No (removable wings)	$1,500 kit
Albatross (RTF)	10 kg	4 hours	4.5 kg	Fiberglass + CF	Partial	No	$4,800
DeltaQuad Evo	10 kg	4.5h / 8.9h record	1-3 kg	FG + CF + Kevlar	Partial	Wing removable	$25,000+
Skywalker X8	~4 kg	45-60 min	1-2 kg	EPO foam	Yes	No	$489-598
Mugin 2600	15 kg	1.5-5h	4 kg	Carbon fiber	No	Wing sections	$2,299+

Key insight: The Albatross kit at $1,500 proves that a 3m wingspan composite airframe is achievable at very low cost. Our target of < $5k per complete unit (with batteries) is realistic. No competitor offers the combination of radio transparency + modular transport + semi-solid batteries.

Architecture

Component: Frame Material

Solution	Advantages	Limitations	Cost (per unit)	Fit
S2 fiberglass skin + PVC foam core + internal CF spar (recommended)	RF transparent skin, strong internal structure, good impact tolerance, easy to repair, $8-19/m² fabric	~30-40% heavier than pure CFRP for equivalent stiffness	Fabric: $200-400; foam: $100-200; CF spar material: $50-100; resin: $80-150; total materials: $430-850	✅ Best balance of RF transparency, cost, repairability
E-glass fiberglass (instead of S2)	Cheapest glass option (~$3-5/m²), RF transparent, easy to work	40% weaker than S2, requires thicker layup → heavier	Materials: $200-500	⚠️ Acceptable budget option, slightly heavier
Pure S2 fiberglass (no CF spar)	Maximum RF transparency, simplest construction	Insufficient wing stiffness at low weight, flutter risk	Materials: $300-600	❌ Stiffness deficit at acceptable weight
Pure CFRP (draft 01 approach)	Lightest, stiffest	Blocks RF — GPS/telemetry degraded, expensive	Materials: $800-1500	❌ Fails radio transparency requirement

Recommendation: S2 fiberglass skin over PVC foam core with unidirectional carbon fiber spar caps (top and bottom of main spar, internal). The CF spar is a narrow linear element (~20-30mm wide per cap) inside the wing — negligible RF blockage. All external surfaces are S2 FG = fully radio transparent.

Component: Construction Method

Solution	Advantages	Limitations	Cost	Fit
Vacuum-bagged foam sandwich (recommended)	Good quality (53% stronger than hand layup), low tooling cost, reproducible	Requires vacuum pump + consumables	Equipment: $500 one-time; consumables: $50-100/unit	✅ Best for low-cost production
Hand layup over foam core	Cheapest, simplest, no equipment needed	Lower quality (more voids), less consistent	Minimal equipment	⚠️ Acceptable for prototypes only
Vacuum infusion	Best quality (71% stronger than hand layup)	More complex setup, higher consumable cost	Equipment: $1000+; consumables: $100-200/unit	⚠️ Worth it at higher volume (>20 units)
Outsourced prepreg manufacturing	Highest quality	Expensive per unit at low volume	$2000-5000/airframe	❌ Exceeds per-unit budget

Component: Foam Core

Solution	Advantages	Limitations	Cost/m²	Fit
PVC Divinycell H60 (recommended)	Good stiffness/weight, closed-cell, 80°C tolerant, industry standard	More expensive than XPS	$50-80/m²	✅ Best value for production
XPS (extruded polystyrene)	Cheapest closed-cell, easy to shape with hot wire	Lower compressive strength, 75°C limit	$10-20/m²	✅ Good budget alternative
EPS (expanded polystyrene)	Very cheap	Absorbs moisture, lowest strength	$5-10/m²	⚠️ Only for non-critical areas

Component: Wing-Fuselage Joint (Modular Assembly)

Solution	Advantages	Limitations	Cost	Fit
Aluminum spar joiner + pin locks (recommended)	Quick assembly (<5 min), proven in RC/UAV, high strength, replaceable	Adds ~100-150g per joint (200-300g total)	$30-60 machined aluminum parts	✅ Simple, reliable, fast
3D-printed spar connector with hinge	Very fast assembly (<2 min), lightweight	Lower strength, fatigue concerns, requires testing	$10-20 per set	⚠️ Good for prototype, risky for production
Bolted flange joint	Very strong, proven in full-scale aviation	Heavier (~200g per joint), slower assembly (10+ min)	$20-40	⚠️ Over-engineered for this scale

Design: Wing spar is a carbon fiber tube or C-channel running the full wing half-span. At the root, it slides into an aluminum joiner tube embedded in the fuselage. Secured with 2 quick-release pins (top and bottom). Electrical connections (servo leads) via a quick-disconnect plug at each wing root.

Component: Battery Technology

Solution	Energy density	Endurance impact	Cycle life	Cost/pack	Fit
Semi-solid Tattu 330Wh/kg 6S (recommended)	315 Wh/kg pack	Baseline (best)	800-1200	~$800-1200 est.	✅ Best endurance per $
Semi-solid Grepow 300Wh/kg 6S	280-300 Wh/kg pack	-5 to -10%	1200+	~$700-1000 est.	✅ Good alternative
Li-Ion 21700 custom pack (6S)	200-220 Wh/kg pack	-25 to -35%	500-800	~$200-400	⚠️ Budget option, significant endurance loss
LiPo 6S (standard RC)	150-180 Wh/kg pack	-40 to -50%	200-500	~$100-200	❌ Too much endurance loss

Weight Budget (S2 Fiberglass Build)

Component	Weight (kg)	Notes
Bare airframe (S2 FG sandwich + CF spar)	3.8-4.5	~30% heavier than pure CFRP; Albatross FG+CF is 3.35 kg
Wing joints (aluminum)	0.2-0.3	Spar joiners + pins + quick-disconnect plugs
Motor + ESC + propeller	0.4-0.6
Wiring, connectors, misc	0.3-0.4
Platform subtotal	4.7-5.8
Payload (camera + gimbal + Jetson + Pixhawk + GPS)	1.47	Fixed
Battery (semi-solid)	2.7-3.8	Remainder to MTOW
Total (target MTOW 10 kg)	~10.0

Conservative estimate: platform 5.3 kg + payload 1.47 kg + battery 3.2 kg = 9.97 kg.

Endurance Estimate (S2 Fiberglass)

Assumptions:

• MTOW: 10 kg
• Platform weight: 5.3 kg (S2 FG airframe + motor + wiring + joints)
• Payload: 1.47 kg
• Battery: 3.23 kg semi-solid at 310 Wh/kg = 1001 Wh
• Cruise power: ~140W (slightly higher than CFRP due to heavier aircraft → higher induced drag)
• Payload power: ~30W (Jetson + camera + gimbal)
• Total system power: ~170W
• Battery reserve: 20%
• Usable energy: 1001 × 0.80 = 801 Wh
• Real-world efficiency factor: 0.75

Theoretical endurance: 1001 / 170 = 5.9 hours Practical endurance (with reserve): 801 / 170 ≈ 4.7 hours Practical endurance (with reserve + real-world losses): 801 × 0.75 / 170 ≈ 3.5 hours

Comparison to Draft 01 (CFRP):

• Draft 01: 5.0 hours practical → Draft 02: 3.5-4.7 hours practical
• Endurance reduction: ~15-30% depending on conditions
• Still competitive with Albatross (4h with LiPo) when using semi-solid batteries

With budget Li-Ion pack instead (to stay under $5k):

• 3.23 kg Li-Ion at 210 Wh/kg = 678 Wh → usable 542 Wh
• Practical: 542 / 170 ≈ 3.2 hours (reserve only) / 2.4 hours (worst case)

BOM Cost Estimate (Per Unit)

Component	Low Est.	High Est.	Notes
S2 fiberglass fabric	$150	$300	~8-10 m² at $15-30/m²
PVC foam core (Divinycell H60)	$100	$200	Wing + fuselage panels
Epoxy resin + hardener	$80	$150	~2-3 kg resin
CF spar material (tube + UD tape)	$50	$100	Spar caps + tubes
Aluminum spar joiners (machined)	$30	$60	2 joiner sets, batch machined
Vacuum bagging consumables	$30	$60	Bag, breather, peel ply, tape
Motor (brushless, ~500W)	$80	$150
ESC (40-60A)	$40	$80
Propeller (folding)	$15	$30
Servos (4× ailerons + elevator + rudder)	$60	$120
Wiring, connectors, hardware	$50	$100
Semi-solid battery (Tattu 330Wh/kg 6S 33Ah)	$800	$1,200	Single pack
RC receiver	$30	$80
Telemetry radio	$100	$300
Transport case / padded bag	$50	$150
Subtotal (airframe + propulsion + battery)	$1,665	$3,080
Pixhawk 6x + GPS	$300	$500	If not already owned
Total BOM (without mission payload)	$1,965	$3,580
Total BOM (with Pixhawk, without mission payload)	$2,265	$4,080

Manufacturing labor (per unit, assuming in-house build with molds amortized):

• First unit (mold making): +$2,000-3,000 tooling
• Subsequent units: ~$500-1,000 labor per airframe (8-16 hours assembly)

Per-unit cost at batch of 5+: $2,800-4,500 (without mission payload) ✅ Under $5k target Per-unit cost at batch of 1 (first prototype): $5,000-7,000 (includes tooling) ✅ Under $7k target

Modular Transport Specifications

Dimension	Value
Wing panel length	~1.50 m (half-span)
Wing panel chord	~0.25-0.30 m
Wing panel thickness	~0.04-0.05 m
Fuselage length	~1.00-1.10 m
Fuselage width/height	~0.15-0.20 m
Assembly time	< 10 minutes (target)
Disassembly time	< 5 minutes

Car trunk fit: 3 sections (2 wings + fuselage) fit in standard sedan trunk (~120×80×45 cm). Wings stack flat, fuselage alongside. ✅

Pickup truck (2 planes): Standard 6.5ft bed (198×130 cm between wheel wells). Each plane's longest component is 150 cm (< 198 cm bed length). Two planes side by side need ~120 cm width (< 130 cm between wheel wells). ✅

Trade-off Summary: S2 Fiberglass vs CFRP

Dimension	S2 Fiberglass (Draft 02)	CFRP (Draft 01)	Winner
RF transparency	✅ Excellent — transparent to GPS, telemetry, data links	❌ Blocks RF, requires external antennas	S2 FG
Cost per unit	$2,800-4,500	$30,000-60,000 (prototype)	S2 FG
Endurance	3.5-4.7 hours practical	5.0 hours practical	CFRP (+15-30%)
Airframe weight	3.8-4.5 kg bare	2.8-3.2 kg bare	CFRP (-25%)
Impact resistance	Good (fiberglass is tough)	Poor (CFRP is brittle)	S2 FG
Field repairability	Easy (fiberglass patches, epoxy)	Difficult (specialized repair)	S2 FG
Manufacturing complexity	Low (basic vacuum bagging)	Medium-High (precise layup)	S2 FG
Transport / modularity	Same	Same	Tie

Conclusion: S2 fiberglass is the clear choice given the revised constraints. The 15-30% endurance reduction vs CFRP is offset by radio transparency (critical for the mission), 10x lower cost, and significantly easier manufacturing and field repair.

Testing Strategy

Integration / Functional Tests

• Static wing load test: 3× max flight load at spar joiner (verify no failure at 3g)
• Wing joint cycling: 100× assembly/disassembly, verify no wear or looseness
• RF transparency test: measure GPS signal strength through airframe skin vs free-air (target: < 3 dB attenuation)
• Assembly time test: verify < 10 minutes from transport case to flight-ready
• Range/endurance test: fly at cruise until 20% reserve, measure actual vs predicted
• Payload integration test: all electronics function under vibration

Non-Functional Tests

• Transport test: load 2 planes in pickup truck, drive 100 km on mixed roads, verify no damage
• Hard landing test: belly landing at 2 m/s descent, verify structural integrity
• Field repair test: simulate wing skin puncture, repair with FG patch + epoxy, verify airworthy in < 30 minutes
• Temperature test: battery + avionics function at -10°C and +45°C
• Battery cycle test: 50 charge/discharge cycles, verify ≥95% capacity retention

Production BOM: 5 UAVs From Scratch

A. One-Time Equipment & Tooling

Item	Qty	Unit Price	Total	Notes
Composite Workshop Equipment
Vacuum pump (6 CFM 2-stage)	1	$280	$280	VIOT or equivalent
Vacuum bagging starter kit (gauges, tubing, valves, connectors)	1	$150	$150
Digital scale (0.1g precision, 5 kg capacity)	1	$50	$50	For resin mixing
Mixing cups, squeegees, rollers, brushes set	1	$80	$80
Large work table (4×8 ft plywood + sawhorses)	1	$150	$150
Self-healing cutting mat (4×8 ft)	1	$80	$80
Foam Cutting
CNC hot wire foam cutter (4-axis, DIY kit)	1	$350	$350	Vortex-RC or similar
Mold Making
MDF sheets for plugs (4×8 ft × ¾")	4	$45	$180	Wing + fuselage plugs
Tooling epoxy + fiberglass for female molds	1	$600	$600	2× wing mold halves + fuselage molds
Mold release agent (PVA + wax)	1	$60	$60
Filler / fairing compound	1	$80	$80	For plug finishing
Sandpaper assortment (80-600 grit)	1	$40	$40
Metal Work
Aluminum spar joiner machining (batch of 12 sets)	1	$400	$400	CNC outsourced, 10 sets + 2 spare
PPE & Ventilation
Respirator (half-face, organic vapor + P100)	2	$40	$80	1 per worker
Nitrile gloves (box of 200)	2	$25	$50
Safety glasses	3	$10	$30
Portable fume extractor / fan	1	$120	$120
Hand & Power Tools
Drill + mixing paddle	1	$80	$80
Jigsaw	1	$60	$60
Rotary tool (Dremel)	1	$50	$50
Heat gun	1	$35	$35
Scissors, utility knives, rulers, clamps	1	$80	$80	Assorted set
Charging & Testing
Battery charger (6S/12S balance, 1000W)	1	$200	$200
Multimeter	1	$30	$30
Servo tester	1	$15	$15
Software & Design
CAD/CAM (FreeCAD / OpenVSP — free)	—	$0	$0	Open source
Hot wire CNC software (included with cutter)	—	$0	$0
EQUIPMENT & TOOLING TOTAL			$3,335

B. Raw Materials (for 5 UAVs + 20% waste margin)

Material quantities per UAV:

• Wing skin area: ~1.6 m² planform × 2 (top+bottom) × 2 layers = ~6.4 m² S2 fabric
• Fuselage skin: ~0.6 m² × 2 layers = ~1.2 m²
• Tail surfaces: ~0.3 m² × 2 layers = ~0.6 m²
• Total S2 fabric per UAV: ~8.2 m² → with waste: ~10 m²
• Foam core per UAV: ~2.5 m² (wings + tail)
• Resin per UAV: ~2.5 kg (fabric weight × 1:1 ratio + extra)

Item	Qty (5 UAVs + margin)	Unit Price	Total	Notes
Structural Materials
S2 fiberglass fabric 6oz (30" wide)	70 yards (~64 m)	$12.50/yard	$875	~10 m² per UAV × 5 + waste
PVC foam Divinycell H60 10mm (1.22×0.81m sheets)	16 sheets	$40/sheet	$640	~2.5 m² per UAV × 5 + waste
Laminating epoxy resin (West System 105 or equiv)	4 gallons	$125/gal	$500	~2.5 kg resin per UAV
Epoxy hardener	2 gallons	$80/gal	$160
Carbon fiber tube (spar, 20mm OD, 1.5m)	12	$25 each	$300	2 per UAV + spare
Carbon fiber UD tape (spar caps, 25mm wide)	30 m	$5/m	$150	5m per UAV + spare
Vacuum Bagging Consumables
Vacuum bag film (5m × 1.5m rolls)	6 rolls	$20/roll	$120	~1 roll per UAV + spare
Peel ply fabric	20 yards	$5/yard	$100
Breather cloth	20 yards	$4/yard	$80
Sealant tape	6 rolls	$12/roll	$72
Hardware (per 5 UAVs)
Aluminum spar joiners	(included in tooling)	—	$0	Batch machined above
Quick-release pins (stainless)	20	$3 each	$60	4 per UAV
Quick-disconnect electrical plugs	10	$8 each	$80	2 per UAV (wing roots)
Misc hardware (bolts, nuts, hinges, control horns)	5 sets	$30/set	$150
RAW MATERIALS TOTAL (5 UAVs)			$3,287
Per UAV materials			~$657

C. Electronics & Propulsion (per UAV × 5)

Item	Qty/UAV	Unit Price	Per UAV	×5 Total	Notes
Motor (brushless ~500W, e.g. Dualsky XM5050EA)	1	$90	$90	$450	Fixed-wing optimized
ESC (40-60A, BLHeli)	1	$50	$50	$250
Folding propeller (13×8 or similar)	2	$15	$30	$150	1 spare per UAV
Servos (digital metal gear, 15-20 kg·cm)	5	$25	$125	$625	2× aileron + elevator + rudder + flap/spare
Pixhawk 6X Mini + GPS	1	$380	$380	$1,900
RC receiver (long range, e.g. TBS Crossfire)	1	$60	$60	$300
RFD900x telemetry pair (shared GCS unit)	1 air + 0.2 GCS	$170 (air)	$170	$850 + $350 GCS = $1,200	1 GCS module shared
Power distribution board + BEC	1	$25	$25	$125
Wiring, connectors (XT90, JST, servo ext.)	1 set	$40	$40	$200
Semi-solid battery (Tattu 330Wh/kg 6S 33Ah)	1	$732	$732	$3,660
ELECTRONICS TOTAL (5 UAVs)				$8,910
Per UAV electronics			~$1,702		Excl. shared GCS telemetry

D. Consumables & Misc (for 5 UAVs)

Item	Total	Notes
Transport bags / padded cases (per UAV)	$300	$60 × 5 (padded wing bags + fuselage bag)
Battery charger cables + adapters	$50
Field repair kit (S2 FG patches, epoxy sachets, sandpaper)	$150	$30 × 5
Spare hardware kit (pins, bolts, servo horns)	$100
Shipping / freight (materials + components)	$400	Estimate
CONSUMABLES TOTAL	$1,000

E. Labor

Role	People	Duration	Rate	Total	Notes
Mold making + setup (one-time)	2	3 weeks	$30/hr	$7,200	2 people × 40h/wk × 3 wk
Airframe layup + cure (per UAV)	2	3 days	$30/hr	$2,880	2 people × 8h × 3 days × 5 UAVs
Post-cure trim, finish, assembly	1	2 days	$30/hr	$2,400	1 person × 8h × 2 days × 5
Electronics integration + wiring	1	1.5 days	$35/hr	$2,100	1 person × 8h × 1.5 days × 5
QA, testing, calibration	1	1 day	$35/hr	$1,400	1 person × 8h × 1 day × 5
LABOR TOTAL				$15,980
Per UAV labor				~$2,516	Including amortized mold making

F. Production Summary — Total Investment for 5 UAVs

Category	Total	Per UAV
A. Equipment & Tooling (one-time)	$3,335	$667
B. Raw Materials	$3,287	$657
C. Electronics & Propulsion	$8,910	$1,782
D. Consumables & Misc	$1,000	$200
E. Labor	$15,980	$3,196
GRAND TOTAL (5 UAVs)	$32,512
Per UAV (all-in, including labor)		$6,502
Per UAV (materials + electronics only, no labor)		$3,306

G. Cost Optimization Options

Optimization	Savings/UAV	Impact
Use XPS foam instead of Divinycell H60	-$90	Slightly lower stiffness, acceptable for prototype
Use E-glass instead of S2 glass	-$100	~40% weaker, needs thicker layup → ~200g heavier
Use Li-Ion 21700 pack instead of Tattu semi-solid	-$400	Endurance drops from 3.5-4.7h to 2.4-3.2h
Self-machine spar joiners (manual lathe)	-$50	Requires metalworking skill
Use cheaper servos ($15 each)	-$50	Lower torque, shorter lifespan
Aggressive budget build	-$690	$2,616/UAV materials only

H. Minimum Viable Team

Role	Count	Skills Required	Commitment
Composite fabricator	1-2	Fiberglass layup, vacuum bagging, mold making	Full-time during build (8 weeks)
Electronics/avionics tech	1	Soldering, Pixhawk configuration, wiring	Part-time (can overlap with fabricator)
Minimum: 2 people for 8 weeks

Timeline for 5 UAVs:

• Week 1-3: Mold making (CNC foam plugs → fiberglass female molds)
• Week 4-5: First 2 airframes layup + cure + trim
• Week 5-6: Next 3 airframes layup + cure + trim
• Week 6-7: Electronics integration all 5 units
• Week 7-8: Testing, calibration, flight testing
• Total: ~8 weeks with 2 people

I. Minimal Absolute Cost (No Labor Accounted)

If labor is free (owner-operators building their own):

Category	Total	Per UAV
Equipment & Tooling	$3,335	$667
Raw Materials	$3,287	$657
Electronics & Propulsion	$8,910	$1,782
Consumables & Misc	$1,000	$200
TOTAL (5 UAVs, no labor)	$16,532
Per UAV (no labor)		$3,306

Absolute minimum per UAV (with budget optimizations from Section G): ~$2,616

References

1-20: See Draft 01 references (all still applicable)

Additional sources: 21. S-Glass vs E-Glass comparison: https://wiki-science.blog/s-glass-vs-e-glass-key-differences 22. Reinforcement Fiber Reference: https://explorecomposites.com/materials-library/fiber-ref/ 23. S-Glass vs Carbon Fiber: https://carbonfiberfriend.com/s-glass-vs-carbon-fiber/ 24. RF Attenuation by composite materials: https://www.rocketryforum.com/threads/rf-attenuation-by-body-tube-nosecone.186634/ 25. Russian foamplast UAV (max radio transparency): https://bulgarianmilitary.com/2023/10/15/russia-unveils-foamplast-fpv-uav-with-max-radio-transparency/ 26. Albatross UAV Kit: https://store.appliedaeronautics.com/albatross-uav-kit/ 27. UAV spar connector development: https://www.konelson.net/home/spar-connector-development 28. Scabro Innovations UAV prototyping: https://scabroinnovations.com/diensten/composite-airframe-prototyping/ 29. Tattu 330Wh/kg 6S pricing — GenStattu: https://genstattu.com/tattu-semi-solid-state-330wh-kg-33000mah-10c-22-2v-6s1p-g-tech-lipo-battery-pack-with-xt90-s-plug/ 30. Pixhawk 6X pricing — Holybro: https://holybro.com/products/pixhawk-6x-rev3 31. RFD900x pricing — DrUAV: https://druav.com/products/rfdesign-rfd900x 32. Composite workshop setup — Fibre Glast: https://www.fibreglast.com/blogs/learning-center/setting-up-a-composite-shop 33. CNC hot wire foam cutter — Vortex-RC: https://www.vortex-rc.com/product/4-axis-diy-hot-wire-cnc-for-rc-hobbyists-aeromodellers-and-designers/ 34. Composite mold making — Canuck Engineering: https://www.canuckengineering.com/capabilities/composite-molds/