Photo: NASA / Jim Ross, public domain, via Wikimedia Commons
Moderate forces, high effectiveness: light ailerons, considerably heavier elevators, a measured light per-g gradient — the felt heaviness is speed, not g.
Sources: AAF Manual AN 01-60JE-1; North American Aviation records.
The P-51D is the definitive American fighter of the Second World War: a laminar-flow wing, a Packard-built Merlin, and the range to escort bombers to Berlin and fight when it got there. It is also, by every account that survives, a beautifully harmonized airplane to fly and an unforgiving one to fly carelessly.
For a simmer the Mustang is the high-speed manual-controls benchmark. There is no boost and no protection: the forces are real, they grow brutally with speed, and G is a constant companion. The profile chases the two things every Mustang pilot report agrees on: silk below 250, iron above 350.
North American designed the original Mustang in 117 days in 1940 for a British purchasing commission that had asked for warmed-over P-40s. The airframe was brilliant; the Allison engine gave up above 15,000 feet. Marrying the airframe to the Merlin in 1942 created the escort fighter the Eighth Air Force was waiting for.
The D model of 1944 brought the bubble canopy and six guns, and Mustangs went on to fly in Korea and in air forces around the world into the 1980s. Hundreds survive on warbird circuits today, which is why credible pilot reports about its handling are still being written.
Each finding pairs our reading with the evidence it rests on. Fly the type and read something wrong? Every claim links straight to the corrections form.
The wartime AAF test is explicit: at both high and slow speeds the controls are very effective with moderate control forces, still highly effective slightly over 500 mph IAS. RAF dive tests found forces "large for small movement" at the same speeds — the primaries disagree in degree but agree the forces build with indicated airspeed.
RAF trials put it plainly: the ailerons feel lighter, especially over small movements, and stiffen only slightly at high speed; the elevators are considerably heavier. This is the reverse of the casual assumption that the Mustang's heaviness lives in roll.
NACA measured ≈2.5 lb/g at mid-CG and 250 mph, with the service bobweight adding 1–7.5 lb/g depending on fuselage-tank state; the era criterion wanted fighters under 6 lb/g. The often-repeated "25–30 lb/g" claim is irreconcilable with the primary measurement. The Mustang's felt heaviness is the q-load with speed, not the per-g gradient.
Trimming is almost constant when maneuvering — rudder and elevator trim with even slight power or airspeed changes, and every configuration change (gear, flaps) is nose-down.
The wartime test reports very little warning of the approaching power-off stall with a right-wing-drop tendency; accelerated stalls do warn with elevator then tail buffeting.
With the 85-gallon fuselage tank full, stick loads rapidly reverse in hard pulls and hands-off trim becomes practically impossible, returning to normal as the tank burns down. The force pipeline has no fuel-CG input, so the profile models the stable normal-CG feel — recorded so nobody "fixes" it toward the legend.
| Gate | Knots | Notes |
|---|---|---|
| VsoStall, landing configuration | 78 | Stall, flaps 40° + gear, ≈90 mph · AAF P-51D Pilot's Flight Operating Instructions (5 April 1944 scan) |
| VrRotation | 90 | Representative |
| VyBest rate of climb | 143 | Best climb ≈165 mph · AAF P-51D Pilot's Flight Operating Instructions (5 April 1944 scan) |
| VappApproach | 100 | 96–100 kt pattern normsRepresentative |
| VleMaximum gear extended | 148 | Gear extend/extended, 170 mph · AAF P-51D Pilot's Flight Operating Instructions (5 April 1944 scan) |
| VfeMaximum flaps extended | 143 | Full 50° flap, 165 mph; higher gates at lesser settings · AAF P-51D Pilot's Flight Operating Instructions (5 April 1944 scan) |
| VneNever exceed | 439 | Max permissible dive, 505 mph IAS · AAF P-51D Pilot's Flight Operating Instructions (5 April 1944 scan) |
The complete starter profile, in the same order and with the same names as the desktop Tuning page. Highlighted rows cite evidence. Hover a row to see its profile-JSON path.
The final overall output scale applied to everything the model produces, before the device cap.
▲ More: everything (spring, loads, effects) gets stronger together. ▼ Less: everything softens together.
Why here: 90%: a warbird runs closer to the device's full authority. This is the strongest overall output in the fleet, and it needs to be.
The base centring force that pulls the stick back to centre. Every other force stacks on it. Too low and the stick feels limp in normal flight; too high and it fights your hand and masks the smaller cues layered above it.
▲ More: firmer centring that resists your hand at all times. ▼ Less: a limper stick that leans on aerodynamic load alone.
Why here: 90%: a fighter stick centres hard. The Mustang's controls were praised for their centering and self-alignment.
A small neutral zone around centre where the spring stays quiet, so tiny movements at rest don't chatter. Wider is calmer but looser; narrower is more precise but can twitch around centre.
▲ More: a calmer but looser centre with more free play. ▼ Less: a tighter centre that may chatter at rest.
Why here: Standard small play for a rod-and-cable fighter.
How much of the spring survives at a standstill, before airspeed can build any aerodynamic force. A high floor keeps the parked stick firm; a low floor gives the loose, cable-slack feel of a parked light aircraft.
▲ More: a firmer stick while parked and taxiing. ▼ Less: a floppier parked stick that only wakes up with airspeed.
Why here: Half strength parked: the stick is alive even before the tail comes up.
The sustained pitch load from elevator deflection and airspeed, balanced independently of roll. This is the main lever behind a type's pitch weight. It does not touch aileron, spring, trim, or buffet forces.
▲ More: heavier sustained pitch forces at speed. ▼ Less: a lighter elevator that takes less muscle to hold.
Elevators considerably heavier — the documented harmony.
The sustained roll load from aileron deflection and airspeed, balanced independently of pitch. Together with the elevator load it sets the control-harmony ratio reviewers talk about.
▲ More: heavier roll forces. ▼ Less: lighter, quicker-feeling ailerons.
Ailerons light and only slightly stiffening with speed.
A master scale over both sustained axis loads, applied before their independent balance. Profiles normally leave this alone and tune the two axis loads instead.
▲ More: both axes load up harder. ▼ Less: both axes lighten together.
Why here: 95%: the highest aerodynamic-load multiplier in the fleet. Combined with the 250 kt reference this is where the iron-above-350 feel comes from.
The indicated airspeed where aerodynamic load reaches its designed full level. It anchors the whole load curve to the aircraft's real speed range: a 172 loads up by 110 knots, a jet much later.
▲ More: loads arrive later; the stick stays light up to a higher speed. ▼ Less: loads arrive earlier and cruise feels heavier.
Why here: 250 kt: escort cruise. The load curve keeps building far beyond it, exactly as the type did.
How sharply stick load builds with airspeed. 1.0 is linear; about 2.0 matches real aerodynamics, where dynamic pressure grows with the square of speed, so controls are much lighter slow and firm up fast. Felt when holding the stick off centre, not at rest.
▲ More: lighter at low speed with a steeper rise toward cruise. ▼ Less: a more linear build that loads up earlier.
Raw hinge moment on a 439 kt envelope — the q-law is what makes 250 kt heavy while approach stays "moderate forces, very effective".
How much the centring itself stiffens with speed, on top of the deflection loads. Zero keeps centre feel constant; more makes the stick centre harder at cruise and looser in the pattern.
▲ More: a centre that hardens noticeably as you go faster. ▼ Less: constant centre feel at every speed.
Centering keeps firming above 90 kt (capped ≈1.40×) instead of flat-lining at approach speed.
A cap on each steady pitch or roll force before it reaches the device, guarding against slamming or saturating the hardware in strong maneuvers.
▲ More: stronger peak steady forces before clipping. ▼ Less: a gentler ceiling; hard maneuvers flatten out sooner.
Why here: 68%: high ceiling. A dive-recovery pull should genuinely resist.
For hydraulically-boosted or fly-by-wire types: how much of the raw aerodynamic load actually reaches the pilot's hand. 1.0 is a fully manual control run; lower values model the artificial-feel systems that isolate the pilot from true surface loads.
▲ More: more raw aerodynamic load reaching your hand. ▼ Less: more isolation, closer to pure artificial feel.
Why here: Inert for a manual control run.
How strongly elevator trim relieves held pitch force and shifts where the stick settles. At 100%, a properly trimmed aircraft needs no held pressure, the trim-away-the-load workflow of real flying.
▲ More: trim removes more of the held pitch force; at 100% full trim zeroes it. ▼ Less: you keep holding force even when trimmed.
Why here: 30%: constant retrimming with speed and power is Mustang flying; trim helps, it does not absolve.
The same relief for roll trim. Most GA types have no real aileron trim, so this stays at zero; types with roll trim get a matching value.
▲ More: roll trim removes more held roll force. ▼ Less: roll trim does less.
Why here: 12%: the type carries aileron trim and needs it with fuselage fuel burned.
Extra spring stiffness as positive G rises above 1G: the pull-up loads your arm as well as the wing. Too little and steep turns feel weightless; too much and maneuvering becomes tiring.
▲ More: pull-ups and steep turns stiffen the stick more per g. ▼ Less: g has less effect; maneuvering stays light.
The NACA-measured light gradient (2.5–4 lb/g class with the service bobweight): above the Extra's near-floor curve, far below the C172's trainer yoke. Speed, not g, carries the heaviness.
Extra centre deadband added at parked and taxi speeds, narrowing away as airflow builds. It keeps the stick calm on the ramp without costing precision in flight.
▲ More: a calmer, looser stick on the ground. ▼ Less: ground handling as precise as flight, and as twitchy.
Why here: Small: a fighter stays precise on the ground too.
How far through the travel the edge-of-throw spring boost begins. High values leave most of the range linear and put a firm wall only near full deflection.
▲ More: the end-of-travel wall starts later, leaving more linear throw. ▼ Less: the wall begins earlier in the travel.
Why here: Wall from 85%.
How strong that edge-of-travel boost is once triggered: a soft warning versus a hard stop near full throw.
▲ More: a harder stop near full deflection. ▼ Less: a softer edge you can push through.
Why here: 28%: firm limits; full deflection at speed was structurally forbidden in the real aircraft.
Rolling surface vibration from wheel speed and surface type: pavement, grass, or gravel under the gear.
▲ More: louder surface texture through the stick. ▼ Less: a smoother taxi.
Why here: 42%: narrow warbird gear on period surfaces transmits everything.
Short discrete bumps from expansion joints, ruts, and rough surface, punctuating the continuous rumble.
▲ More: sharper hits from joints and ruts. ▼ Less: softer ground detail.
Why here: 30%: grass-field texture.
Vibration under brake pressure while rolling. Invisible braking feels wrong; too much makes every stop feel like an anti-skid event.
▲ More: more shudder under braking. ▼ Less: quieter stops.
Why here: 40%: heel brakes you respect; a Mustang on its nose is a write-off.
The fore-aft pull on the pitch axis from acceleration on the ground. The takeoff surge draws the column aft; braking pushes it forward.
▲ More: a stronger fore-aft pull under acceleration and braking. ▼ Less: a subtler surge cue.
Why here: 24%: 1,490 hp of surge, and the tail coming up, deserve a firm cue.
Airframe shake approaching the stall and while the stall warning is active: how loudly this wing announces it is unhappy. Types with a crisp break get modest buffet and let the horn carry the warning.
▲ More: a louder pre-stall shake. ▼ Less: a quieter wing; the horn carries the warning.
The type's power-off stall warns little; a big synthetic buffet would contradict the documented character.
Airframe shake past the overspeed warning, the airframe's own protest at exceeding Vne/VMO.
▲ More: a harsher protest past the redline. ▼ Less: a gentler overspeed warning.
Why here: 60%: approaching placard limits in a Mustang was a structural event and it sounds like one through the stick.
Low-frequency airframe vibration with flaps extended into the airflow, in the speed window where they actually work the air.
▲ More: a rougher ride with flaps working the air. ▼ Less: smoother approach flap.
Why here: 30%: the big plain flaps shake honestly at approach speed.
Airframe drumming from retractable gear hanging in the airstream. Zero for fixed-gear types, where the airframe never changes shape.
▲ More: more drumming with the wheels hanging out. ▼ Less: cleaner gear-down flight.
Why here: 24%: legs in a fast slipstream.
Random shake from short-term G variation in rough air, so bumpy air is felt and not just seen.
▲ More: rough air hits the stick harder. ▼ Less: calmer chop.
Why here: 36%: wing loading between trainer and airliner; it punches through chop.
Continuous powerplant vibration following RPM between idle and full power, the ever-present reminder that something is burning fuel up front.
▲ More: more engine through the stick. ▼ Less: a quieter powerplant.
Why here: 30%: the highest engine presence in the fleet. Twelve cylinders of Merlin at 3,000 rpm are a physical experience, and the airframe never lets you forget them.
The one-shot kick when the wheels meet the runway, scaled by sink rate: a greaser whispers, a firm arrival thumps.
▲ More: a harder kick at touchdown. ▼ Less: softer arrivals.
Why here: 75%: a 10,000 lb tailwheel arrival lands with authority.
The short shudder of gear extension and retraction in motion. Zero for fixed-gear types.
▲ More: a stronger shudder while the gear cycles. ▼ Less: a subtler gear cue.
Why here: 50%: the wide gear coming up and down is a long, felt cycle.
Continuous vibration only while the sim reports the flap surfaces actually travelling. It follows real actuator motion and failures, not an estimated timer.
▲ More: more vibration while the flap surfaces travel. ▼ Less: quieter flap runs.
Why here: Hydraulic flaps in motion.
The small airframe settle when flap-surface travel completes, driven by the surface arriving, not the handle command.
▲ More: a firmer settle as flaps reach the notch. ▼ Less: a softer arrival.
Why here: A settle at each set point.
The short mechanical click on each flap-handle detent. The handle, not the surfaces.
▲ More: a sharper detent click. ▼ Less: a fainter click.
Why here: 30%: the cockpit lever is mechanical and definite.
The sustained pitch-force change from flap drag at airspeed. Extending flaps should change what your hand holds, not just make noise.
▲ More: a bigger stick-load change when the flaps come out. ▼ Less: less trim shift from flap.
Why here: Modest sustained change; the real trim change is flown out.
The trim-like load change from gear hanging in the airflow. Zero for fixed-gear types.
▲ More: a bigger load change from the gear. ▼ Less: less.
Why here: Slight rebalance with the wheels out.
Power-on pitch bias from propwash over the elevator: why adding power on a prop aircraft nudges the nose and the stick. Zero for jets.
▲ More: a stronger power-on pitch nudge. ▼ Less: power changes feel more neutral.
Why here: 24%: an 11-foot prop washing the tail. Power changes swing the nose and the stick tells you first, especially on the go-around.
Resistance proportional to the aircraft's pitch rotation rate. It settles the stick after abrupt pitch inputs; zero on both axes turns rate damping off.
▲ More: the stick settles harder against pitch rotation. ▼ Less: less resistance to quick pitch changes.
Why here: 9%: heavy surfaces settle firmly after inputs.
The roll-axis counterpart: damping against roll rate to stop post-input wobble.
▲ More: more resistance to roll rate. ▼ Less: a livelier roll axis.
Why here: Matching settle.
How hard the elevator falls forward at rest, the parked slump of an unpowered control run. Zero disables it.
▲ More: a heavier forward slump at rest. ▼ Less: a lighter parked lean.
Why here: The parked elevator lies against its stop; every warbird walkaround photo shows it.
Whether this feature is active in this profile.
Taildragger — the parked-stick forward-drop model doesn't apply.
The airspeed where the forward slump has fully faded, typically almost as soon as airflow builds on the takeoff roll.
▲ More: the slump lingers further into the takeoff roll. ▼ Less: it vanishes almost as soon as you roll.
Why here: Lifts as the tail comes alive on the roll.
How firmly the stick holds the autopilot's commanded position while following is active.
▲ More: a firmer hold on the AP's commanded position. ▼ Less: softer, easy to override.
Why here: Minimal hold.
Research retune from wartime primaries: light NACA-measured per-g gradient (the old firm curve was the legend, not the measurement), AFDU harmony, reduced stall buffet to the documented little-warning character.
Initial starter baseline.
If your time in the type says this page got something wrong, correct it here.
This page is built from cited references, and real time in the type beats a citation. Quote the claim that reads wrong and tell us what the actual aircraft does. Corrections go to the maintainer for review and feed the next revision of this research.
What the research could not pin down. If you fly the type, or can point at a source, a correction on any of these feeds the next revision directly.
Absolute magnitudes are bench-set; the only period feel-around-neutral statement is "not conscious of moving the control column".
Breakout force — no period measurement found.
Open conversation about flying and tuning the North American P-51D Mustang, in the community forum. Corrections above go privately to the maintainer; hangar talk is public.