MQ-25 being unmanned reduces the need for extreme low observables.
MQ-25 was based on a VLO design. MQ-25 as it is today is not VLO, but this has nothing to do with being unmanned. There are plenty of unmanned VLO aircraft out there, manned vs. unmanned has nothing to do with VLO.
The slower speed and long straight wing of the MQ-25 allows it to have excennet range for it's size. Most of the missions listed do not need high speed.
No, having a really high fuel fraction helps more with the range. If more than 60% of your mass is fuel you're going to do pretty well on range. There are operational military aircraft with fuel fractions much higher than that.
The Breguet Range Equation is the governing framework here. For jets it takes the form:
Code:
R = (V/TSFC) × (L/D) × ln(W₀/W₁)
Where V is cruise speed, TSFC is thrust-specific fuel consumption, L/D is lift-to-drag ratio, and ln(W₀/W₁) is the natural log of the weight ratio — which is directly driven by fuel fraction. That last term is why fuel fraction matters so much: range scales logarithmically with it, not linearly. A fuel fraction of 0.40 gives ln(1/0.60) ≈ 0.51; raising it to 0.70 gives ln(1/0.30) ≈ 1.20 — more than doubling the range contribution from that term alone.
The three levers pulling in the same direction are: low TSFC (high bypass ratio turbofan), high L/D (efficient aerodynamics at cruise), and high fuel fraction. Speed is a direct multiplier on range but kills L/D — faster means more wave drag, so the product V×(L/D) tends to peak at subsonic cruise conditions, which is why transports and long-range UAVs cruise in the M0.80–0.85 window rather than M1.5+. Unless there has been some advancement in transonic and supersonic drag reduction, or the aircraft is tailless.
Both bypass ratio and fuel fraction matter enormously but through different mechanisms. Bypass ratio reduces TSFC — a high-bypass turbofan (BPR ~10–12, e.g. CFM LEAP) has TSFC around 0.50–0.55 lb/lbf·hr versus a low-bypass afterburning fighter engine (BPR ~0.3, TSFC ~2.0+ in reheat).
But TSFC sits outside the log term, so it scales range linearly. Fuel fraction sits inside the log, so its effect is also roughly linear for small fractions but amplifies as the fraction climbs. For a high-bypass transport with low TSFC, fuel fraction is the dominant variable at cruise. For a fighter using reheat, TSFC is so punishing that fuel fraction has to be heroic just to achieve modest range — which is why fighters have been typically range-limited.
Typical fighter fuel fractions run 0.25–0.35 on internal fuel. The F-16 is roughly 0.26, the F-15C around 0.27, the F/A-18C about 0.25. Clean internal fractions are constrained by the structural weight of a maneuvering airframe, large engines, and radar/avionics mass. Conformal tanks push these up modestly; the F-15E with CFTs reaches ~0.35. The F-22 is closer to 0.29 internally.
High-fraction UAVs achieve their numbers by doing the opposite: no pilot life support, no ejection seat, minimal avionics mass, no sustained g-load structure, and mission profiles that are pure loiter. The RQ-4 Global Hawk is ~0.55 internal, and some purpose-built HALE designs reach 0.70+. At 0.70 the log term becomes ln(1/0.30) = 1.204 — nearly 2.4× the contribution of a 0.27 fighter fraction (ln(1/0.73) = 0.315). That gap explains why a Global Hawk achieves 34+ hour endurance while an F-16 is calling the tanker in 90 minutes.
TL;DR; Range scales linearly with bypass ratio or fuel consumption, but scales LOGARITHMICALLY with fuel fraction. Aircraft with very high fuel fractions have been produced for many years now. It's a well understood, well solved set of problems.
Also, F/A-XX is still a strike fighter.
