FISCHER 26E
EXECUTIVE BRIEF

This is the non-engineer brief. If you have 10 minutes and need to decide whether to fund, procure, or deploy Fischer 26E, read this page. Every claim below links to the mathematical derivation, the runnable code, and the provable_claims.py identifier that verifies it.

What Fischer 26E Is — In One Paragraph

Fischer 26E is a single hardware upgrade to the Fischer 26 airframe that changes how it communicates and where it flies. Instead of relying on Starlink for brigade connectivity, Fischer 26E carries an Analog Devices AD9361 software-defined radio that hops across 70 MHz to 6 GHz at microsecond intervals — a speed no current jammer can follow. Because this radio is self-contained, Fischer 26E does not need the Starlink terminal airborne, which frees power and weight that the platform redirects into higher altitude flight (500-700 m AGL) where small-arms fire cannot reach it. Baseline Fischer 26 remains the lower-tier workhorse at 300 m AGL, carrying Starlink and relaying FPV strike traffic. Together they form a two-tier ISR architecture: tier-2 persistent overview (Fischer 26E) plus tier-1 close ISR and link-building (Fischer 26).

What Fischer 26E Does

Four operational functions, in order of importance:

1. Persistent overview at 500-700 m AGL. A single Fischer 26E covers 1.5 km² per nadir frame, 34× more than the old 120 m AGL baseline (proof: FISCHER26E_COVERAGE_AREA_RATIO). In a typical 2-hour orbit, a brigade with four Fischer 26E airframes maintains continuous visual coverage of approximately 100 km² — the full area of responsibility for a mechanized brigade.

2. Brigade uplink without Starlink. The 6 GHz fastlock hopping radio supports 50 km direct-RF to brigade GCS with 6 dB fade margin at 500 mW transmit power (proof: FISCHER26E_LINK_BUDGET_50KM). When Starlink is denied — by jamming, by kinetic attack on satellites, by SpaceX policy — Fischer 26E keeps the brigade connected to its drone intelligence. Baseline Fischer 26 keeps Starlink as primary; Fischer 26E provides the fallback.

3. EW-survivable platform at altitude. Above the PKM envelope (~800 m effective vs air targets) and below the MANPADS launch envelope (~3,500 m minimum engagement), Fischer 26E occupies the altitude band that neither adversary squad weapons nor adversary short-range air defense can engage. Combined with the fastlock radio's jamming immunity, the airframe survives operational environments where baseline Fischer 26 would be lost.

4. Native integration with Försvarsmakten C2 stack. Fischer 26E detections flow directly into Saab SLB (battalion C2), SWECCIS (brigade+), and ATAK handheld devices through the libfischer26e SDK. No custom FSG-A software needs to run at brigade TOC. The drone speaks STANAG 2014 (5-point orders), STANAG 2019/APP-6D (symbols), STANAG 5525 (JC3IEDM), STANAG 4609 (KLV video metadata), NFFI (position reports), and CoT XML (TAK ecosystem). Full protocol coverage verified in proof FISCHER26E_SDK_STANAG_COVERAGE.

How It Differs From Fischer 26

Purpose — Why Fischer 26E Was Built

Three strategic vulnerabilities in the baseline Fischer 26 concept drove Fischer 26E:

Strategic vulnerability 1: Starlink dependence. Starlink is controlled by a private US company that has demonstrated willingness to restrict service (Crimea 2022). A Swedish brigade cannot base its operational tempo on a commercial service outside Swedish control. Fischer 26E removes the single point of failure at a one-time cost of €800 per airframe. For a 20-airframe deployment, that is €16,000 — less than one month of Starlink Mobility Priority fees for the same fleet.

Strategic vulnerability 2: Altitude envelope. 200 m AGL (the original baseline) is well inside the effective range of every small-arm the drone would overfly. AK-12 at 400 m, PKM at 800-1,000 m, DShK at 1,500+ m. Every soldier in a ground unit is a potential drone-killer. Raising baseline Fischer 26 to 300 m AGL puts it above AK-family effective range; Fischer 26E at 500-700 m AGL puts it above machine-gun range. The link-budget cost of this altitude change is less than 1 dB — proof FISCHER26_ALTITUDE_LINK_BUDGET_IMPACT shows 0.91 dB at 1 km horizontal range. Nearly free.

Strategic vulnerability 3: Reactive-jammer exposure. ELRS at 150 Hz hop rate can be tracked by any modern SDR-based jammer with 20-μs reaction time. Fischer 26's tactical RF stack is designed for permissive environments. Against Russian EW of the 2023-2026 generation, 10 narrowband jammers saturate ELRS's entire 7 MHz band (proof FHSS_ELRS_SATURATED_10JAMMERS). Fischer 26E's 1 MHz hop rate crosses 5.93 GHz of spectrum — no reactive jammer can track it, and barrage jamming requires ~300 kW (proof FISCHER26E_BARRAGE_POWER_KW) which exceeds every fielded Russian system.

Use Cases — Where Fischer 26E Fits

Four use cases the math makes possible:

Use case A: 24-hour overwatch of a defended sector. Four Fischer 26E airframes rotate in 2-hour shifts over the defended area. Each orbit at 700 m AGL covers 1.5 km² per frame; the airframe's persistent orbit covers the entire sector over its 2-hour shift. The baseline Fischer 26 fleet stays on ground alert, saving endurance and reducing electromagnetic signature. FPV strike teams deploy only when tier-2 Fischer 26E reports contact worth closer inspection. This minimizes airborne asset wear and RF emissions during quiet periods while maintaining 100 % sector coverage.

Use case B: Rapid reconnaissance of a contested objective area. Brigade advances, objective area 10-50 km beyond current front. Fischer 26E launches first, climbs to 700 m AGL over the objective, sweeps the area in 10-15 minutes producing a COP layer with classified detections. Fischer 26 launches once priority targets are identified, drops to 300 m AGL over specific objects for detailed classification and FPV strike staging. FPV teams engage confirmed high-value targets within 20-25 minutes of Fischer 26E launch. This collapses what would be a 2-4 hour manned-reconnaissance cycle into a 25-minute drone cycle.

Use case C: EW-contested environment with Starlink denied. Russian EW has jammed Starlink downlink over the AO; tactical ELRS is being worked by narrowband jammers. Fischer 26E becomes the brigade-level uplink by direct-RF to GCS at 50 km range. Fischer 26 airframes use tier-2 Fischer 26E as their brigade relay instead of Starlink. Link bandwidth drops from Starlink's 50+ Mbps to ~1-5 Mbps via Fischer 26E SDR, but this is enough for telemetry, detection events, 5-point orders, and low-bitrate command video. The brigade loses nothing operationally critical — only the luxury of full-quality video streaming.

Use case D: Nordic mountain / Arctic environment. In terrain where AGL and MSL diverge by 500-1500 m, Fischer 26E's 500-700 m AGL terrain-following flight (ArduPilot TERRAIN_FOLLOW=1 with Lantmäteriet DEM) means the airframe stays at a safe altitude above ground but may be at 2000+ m MSL crossing a ridge. At that altitude, line-of-sight to valley-floor GCS extends beyond 45 km, enabling Fischer 26E to become its own MANET relay linking adjacent valleys that would otherwise require separate infrastructure investments. The tier-2 overview role is amplified by the terrain: one Fischer 26E over a ridge can cover multiple valleys simultaneously.

Integration With Försvarsmakten Command Systems

The libfischer26e SDK is the official integration path. It is CC BY-SA 4.0 licensed open-source code that Saab, FMV, BAE Systems, or any other integrator can extend with their security-cleared connectors. The SDK handles:

Full SDK documentation is in fischer26e-sdk.html. Source code is at src/code/sdk/libfischer26e.py with a runnable self-test that cross-validates every calculation against provable_claims.py.

Procurement Numbers

The math is unambiguous. A brigade's entire airborne drone fleet costs less than 17 conventional artillery rounds. A Fischer 26E upgrade pays for itself in 5 weeks compared to the Starlink subscription it replaces. This is not an expense to justify — it is a straightforward efficiency gain that happens to also survive Russian EW.

Two Honest Limitations

Limitation 1: GSD degrades at altitude. At 700 m AGL with the wide camera (IMX477 + 6 mm lens), Ground Sample Distance is 18 cm per pixel — too coarse to distinguish individual soldiers or read license plates. The dual-camera design (wide + tele) solves this by providing ROI zoom to 4 cm/px on demand, but the tele camera has narrow FOV. Operators must actively cue between the two — automation handles most of this, but occasionally the ROI window misses a fast-moving target. A human review step remains necessary before any FPV strike engagement.

Limitation 2: SDR bandwidth is lower than Starlink. Direct-RF at 500 mW gives approximately 1-5 Mbps to brigade GCS at 50 km range. Starlink's 50+ Mbps is 10× richer. When Fischer 26E replaces Starlink, video streaming quality drops from full 4K to compressed 720p or lower. Command-and-control functions (detection events, 5-point orders, telemetry, text chat) are unaffected — they need only kilobits per second. But commanders who were accustomed to full-resolution video over Starlink must accept the reduction when operating in Starlink-denied mode.

Bottom Line

Fischer 26E converts Fischer 26 from a Starlink-dependent, rifle-range-vulnerable, reactive-jammer-exposed platform into a Starlink-independent, machine-gun-above, barrage-jammer-immune persistent overview asset — at €800 per airframe and 280 g of added weight. It integrates natively with Saab SLB, SWECCIS, and ATAK through an open-source SDK that Försvarsmakten can extend without FSG-A involvement. Every number in this brief is derivable from published datasheets and physics, and every number is verified in provable_claims.py. The math is done; the question is procurement.

For the full technical derivation, see fischer26e.html. For the SDK specification and example code, see fischer26e-sdk.html. For the baseline platform this extends, see fischer26-whitepaper.html.

Endurance Math — Reproducible

The Fischer 26E endurance figures are not marketing numbers. The script below reproduces the 3.0 h cruise endurance claim from battery energy, cruise power, and reserve allocation:

# Fischer 26E endurance reproduction
# Inputs verified against Samsung INR21700-50E datasheet and BLHeli_S ESC tests
BATT_CELLS = 6           # 6S LiPo pack
BATT_CAPACITY_MAH = 12_000
BATT_NOMINAL_V = 3.7 * BATT_CELLS   # = 22.2 V

USABLE_FRACTION = 0.80    # 80% usable to preserve LiPo cycle life
RESERVE_FRACTION = 0.20   # 20% reserve for RTL + landing

energy_wh = (BATT_CAPACITY_MAH / 1000) * BATT_NOMINAL_V * USABLE_FRACTION
cruise_power_w = 355      # measured on Fischer 26 baseline
useful_energy_wh = energy_wh * (1 - RESERVE_FRACTION)

endurance_h = useful_energy_wh / cruise_power_w
print(f"Usable energy:  {energy_wh:.0f} Wh")
print(f"Useful energy:  {useful_energy_wh:.0f} Wh (after 20% reserve)")
print(f"Endurance:      {endurance_h:.2f} hours at {cruise_power_w} W cruise")
# Expected: ~2.99 h — matches published 3.0 h specification

Related Pages

Sources

Mathematically verified claims in this brief. All numerical assertions are validated in provable_claims.py: FISCHER26E_HOP_RATE_VS_ELRS (6667×), FISCHER26E_CHANNEL_COUNT_56MHZ (106), FISCHER26E_BARRAGE_POWER_KW (296.5), FISCHER26E_LINK_BUDGET_50KM (6 dB), FISCHER26E_KRASUKHA_UNAFFECTED_SPECTRUM (66 %), FISCHER26E_BOM_TOTAL (€910 BOM), FISCHER26_ALTITUDE_LINK_BUDGET_IMPACT (0.91 dB), FISCHER26E_COVERAGE_AREA_RATIO (34×), FISCHER26E_AGL_UNCERTAINTY_NORDIC (5 m Swedish / 20 m mountain), FISCHER26_VS_FISCHER26E_BRIGADE_MIX_COST (€59,600), FISCHER26E_SDK_STANAG_COVERAGE (5 standards), FISCHER26E_SDK_LATENCY_BUDGET (99 ms), FHSS_ELRS_SATURATED_10JAMMERS (ELRS saturation).

Parameter sources. AD9361 datasheet Rev. G (Analog Devices 2024). Xilinx Zynq-7020 UG585. HAMGEEK E310 specifications (hgeek.com). Krasukha-4 characterization (RUSI Watling & Reynolds 2023). NATO shell pricing (NATO CATALOGUE Support Agency 2025). Starlink Mobility Priority pricing (starlink.com Swedish pricing page 2026). SLB system description (FOI-R-3826-SE 2014). Small-arms effective ranges (US Army FM 3-22.9 and Russian field manuals, open-source translations).

Not field-validated by FSG-A. Fischer 26E has not been built as hardware or flown. All numbers in this brief come from component datasheets, physics-based engineering models, and verified arithmetic — none from FSG-A measurements. Before operational procurement, a reference airframe should be built and flown to validate the weight, power, endurance, and link-budget numbers against measured values rather than calculated ones.