Heavyweight wingless research aircraft built to prove that a blunt, half-cone body could generate enough lift for a controlled atmospheric reentry and a precise unpowered runway landing — the aerodynamic path that later shaped the Space Shuttle.
The Northrop M2-F2 was the first of NASA’s heavyweight, entry-configuration lifting bodies — a metal evolution of Dryden’s plywood M2-F1 “flying bathtub.” The “M” stands for manned, the “F” for flight version. Shape came from Ames and Langley wind-tunnel work: a modified half-cone with a rounded bottom, flat upper surface, blunt nose, and twin vertical fins.
NASA awarded Northrop the contract in June 1964. The finished vehicle reached the Flight Research Center (now Armstrong) in June 1965. It was air-launched from a modified NB-52 mothership at about 45,000 ft — the same pylon used for the X-15 — then glided to Rogers Dry Lake. Although an XLR-11 rocket was later installed, every M2-F2 flight remained unpowered.
Data from the M2 series — together with the HL-10 and X-24 — convinced NASA that an unpowered horizontal landing was viable for a reusable orbital vehicle, and helped retire the idea of landing jets on the Space Shuttle orbiter.
| Length | 6.76 m (22 ft 2 in) |
|---|---|
| Span (effective) | 2.95 m (9 ft 8 in) |
| Height | 2.90 m (9 ft 6 in) |
| Planform / “wing” area | 14.9 m² (160 ft²) |
| Configuration | Half-cone lifting body · twin fins |
| Crew | 1 pilot |
|---|---|
| Length overall | 6.76 m (22 ft 2 in) |
| Span | 2.95 m (9 ft 8 in) |
| Height | 2.90 m (9 ft 6 in) |
| Planform area | 14.9 m² (160 ft²) |
| Empty weight | 2 096 kg (4 620 lb) |
| Gross weight | 2 722 kg (6 000 lb) |
| Max takeoff weight | 3 395 kg (7 485 lb) |
| Powerplant | 1 × Reaction Motors XLR-11 |
| Thrust (installed) | 35.6 kN (8 000 lbf) |
| Launch method | NB-52 pylon drop · ~Mach 0.6–0.8 |
| Max speed (glide) | Mach 0.707 / 750 km/h |
|---|---|
| Typical release | 13 716 m (45 000 ft) |
| Service ceiling (carried) | 14 000 m (45 900 ft) |
| Stall speed (approx.) | 200 km/h (124 mph) |
| First-flight landing | ~320 km/h |
| Glide ratio | ~2.5 : 1 to 3.0 : 1 |
| Range (spec table) | 15.9 km (8.6 nmi) |
| Thrust / weight | 1.3 (engine installed) |
| Flights as M2-F2 | 16 unpowered glides |
| Powered M2-F2 sorties | None — engine never fired in flight |
| Engine | Reaction Motors XLR-11 (Thiokol LR-11) |
|---|---|
| Type | Four-chamber liquid rocket |
| Thrust | 35.6 kN (8 000 lbf) combined |
| Propellants | LOX + 50% water / ethyl alcohol |
| Ignition | Hydrogen-peroxide starter |
| Vectoring | None — fixed engine, aero control |
| Design burn | ~120 s / ~200 gal propellant |
| Heritage | Surplus X-1 / X-15-class chambers |
The M2-F2 was designed as a rocket-powered follow-on to the unpowered M2-F1. After the 21 November 1966 glide, the vehicle was grounded 5.5 months while engineers led by Meryl DeGeer fitted the XLR-11 and worked stability issues seen on the B-52 drops.
Two checkout glides with the engine aboard — Flight 15 (Jerry Gentry, 2 May 1967) and Flight 16 (Bruce Peterson, 10 May 1967) — were intended to clear the vehicle for powered work up to about Mach 2. Flight 16 crashed. The rocket was never lit on an M2-F2 mission.
Captive carriage began 23 March 1966. Milton O. Thompson made the first free glide on 12 July 1966: dropped from 45,000 ft, peaked near 727 km/h, and landed at about 320 km/h on the packed clay of Rogers Dry Lake. Subsequent sorties mapped damper-on and damper-off handling, flap effectiveness, and the 360° overhead approach that would become a lifting-body signature.
| Flt | Date | Pilot | Mach | km/h | Alt m | Time | Comments |
|---|---|---|---|---|---|---|---|
| #1 | 1966-07-12 | Thompson | 0.646 | 727 | 13 716 | 03:37 | First M2-F2 flight. Unpowered glide. ~320 km/h landing. |
| #2 | 1966-07-19 | Thompson | 0.598 | 634 | 13 716 | 04:05 | Lateral stability, longitudinal trim, landing characteristics. |
| #3 | 1966-08-12 | Thompson | 0.619 | 692 | 13 716 | 04:38 | Increasing Mach, minimum damper requirements, S&C. |
| #4 | 1966-08-24 | Thompson | 0.676 | 718 | 13 716 | 04:01 | Damper needs, L/D, elevon response, flap effectiveness. |
| #5 | 1966-09-02 | Thompson | 0.707 | 750 | 13 716 | 03:46 | 360° overhead approach. Damper-off handling. Fastest M2-F2 Mach. |
| #6 | 1966-09-15 | Peterson | 0.705 | 750 | 13 716 | 03:30 | Pilot checkout. |
| #7 | 1966-09-20 | Sorlie | 0.635 | 678 | 13 716 | 03:31 | Pilot checkout. |
| #8 | 1966-09-22 | Peterson | 0.661 | 702 | 13 716 | 03:53 | Longitudinal and lateral S&C with dampers. |
| #9 | 1966-09-28 | Sorlie | 0.672 | 713 | 13 716 | 03:53 | Complete checkout; extend envelope. |
| #10 | 1966-10-05 | Sorlie | 0.615 | 692 | 13 716 | 03:45 | S&C with dampers on and off. |
| #11 | 1966-10-12 | Gentry | 0.662 | 702 | 13 716 | 03:54 | Pilot checkout. |
| #12 | 1966-10-26 | Gentry | 0.605 | 642 | 13 716 | 03:47 | S&C at 7° and 11° AoA; upper-flap effectiveness. |
| #13 | 1966-11-14 | Gentry | 0.681 | 716 | 13 716 | 04:21 | Stability, control, and performance. |
| #14 | 1966-11-21 | Gentry | 0.695 | 735 | 13 716 | 03:50 | Last glide before XLR-11 installation layover. |
| #15 | 1967-05-02 | Gentry | 0.623 | 661 | 13 716 | 03:51 | Post-engine-install checkout glide. |
| #16 | 1967-05-10 | Peterson | 0.612 | 649 | 13 716 | 03:43 | PIO on approach. Gear not locked. Cartwheel crash on lakebed. |
| Primary cause | Pilot-induced oscillation at low AoA preflare |
|---|---|
| Airframe factors | Insufficient fin authority · roll-spiral coupling |
| Contributors | Offset landing area · helicopter distraction |
| Immediate action | Program hold · HL-10 temporarily grounded |
| Fix | Third central fin + SAS → M2-F3 |
| Cultural note | Crash film used in The Six Million Dollar Man |
Homebuilt plywood-and-steel “flying bathtub.” Towed by Pontiac and later C-47. Proved the half-cone could be flown by a pilot before NASA spent metal-airframe money.
1963–1966 · lightweightFirst heavyweight Ames shape. Twin fins, aluminium semi-monocoque, B-52 launch, XLR-11 bay. Sixteen glides. Destroyed in landing crash; airframe salvaged.
1966–1967 · unpoweredThird vertical fin, RCS roll jets, refined SAS. 27 flights 1970–1972 including powered runs to Mach 1.6 / 71,500 ft. Preserved at the National Air and Space Museum.
1970–1972 · poweredNegative-camber “horizontal landing” body. Best-handling of the original heavyweights; program altitude and speed records. Bruce Peterson also made its first flight.
37 flightsAir Force SV-5 / X-24 line flown in parallel at Edwards. X-24A later informed X-38 crew-return studies. Often photographed with M2-F3 and HL-10 on the lakebed.
joint programUnpowered runway landing of a low-L/D reentry vehicle is the operational payoff. Sierra Space Dream Chaser inherits the lifting-body idea via HL-20 / HL-10 geometry.
legacy
Unlike the M2-F1’s tube-and-plywood shell, the M2-F2 used an aluminium-alloy semi-monocoque: skin panels over stringers and bulkheads, sized for rocket loads and B-52 pylon carriage. A fiberglass nose set the blunt entry contour and served as a thermal/shape cap rather than a full heat shield — this was an atmospheric research vehicle, not an orbital reentry article.
Outboard vertical fins supplied what little directional stability the half-cone possessed. After Flight 16 those fins, the canopy, and the main gear were among the wreckage. Reconstruction added a central fin on the upper surface, moved mass forward, and improved cockpit visibility — the difference between M2-F2 and M2-F3 in every three-view.
Not a mass-fraction pie — the M2-F2 was a unique research article. Bars indicate where the airframe’s identity lived: aluminium structure, composite nose fairing, and a large internal rocket bay that flew as dead weight on every M2-F2 glide.
Allen and Eggers show a blunt lifting body can reach L/D ~1.5. NASA FRC proposes cheap flight test instead of capsules-only reentry.
Wooden M2-F1 validates the shape. June 1964: Northrop hired to build the heavyweight M2-F2 (and HL-10).
Vehicle arrives at Edwards. Ames 40×80 tunnel work continues; 100 tunnel hours logged in two weeks that August.
Carried aloft on the B-52 without release. Systems and pylon compatibility.
Drop from 45,000 ft. The heavyweight Ames shape flies.
PIO, offset lakebed, six cartwheels. Program halted. Footage later opens The Six Million Dollar Man.
Third fin, SAS, RCS. ~$700,000. First M2-F3 glide 2 June 1970, Bill Dana.
27 M2-F3 flights to Mach 1.6 / 71,500 ft. Final flight 20 December 1972. Airframe preserved at NASM.
| Primary question | Can a wingless body land on a runway? |
|---|---|
| Design philosophy | Shape-as-wing · low L/D · precise flare |
| Not optimized for | Cruise · endurance · combat |
| Immediate successor | M2-F3 (same article, third fin) |
| Program payoff | Shuttle unpowered landing confidence |
Low-cost plywood article. Tow tests before any heavyweight metal was cut.
Aluminium, B-52 launch, rocket bay, research instrumentation. Answer: yes, until the landing.
Center fin and SAS. Then open the envelope with the XLR-11 and hand the data to Shuttle.