Aerospace Engineering: Military Missions, Design, and the Future
Motivation and Overview of Aerospace Engineering Missions
Speaker's Background and Motivation
The speaker, Ashton's dad, is an aerospace engineer with a career focused on understanding and designing air platforms for military missions.
His daughter, Ashton, graduated from the university and works as a rocket test engineer at Blue Origin.
He grew up in a military family, living at various Air Force Bases (Edwards, Travis, Wright-Patterson).
Recommendation: Visit the Air Force Museum at Wright-Patterson Air Force Base, considered the best airplane museum in the world, especially for military aircraft. It features four hangars and significant historical aircraft like the Memphis Belle, Bockscar (which dropped the Fat Man bomb), B-52s, B-2s, F-22s, various missiles, engines, and the rare (only one in existence after another crashed).
Core Motivation: A desire to be involved in operations, design, engineering, and understanding why things work, which is rooted in physics and math.
Dr. Theodore Von Kármán's Insight: As Chief Scientist of the Air Force during World War II, his 1947 report, "Toward New Horizons," emphasized that scientific results are inefficiently used by airmen without understanding, and scientists cannot produce useful results without understanding operations. This mutual understanding is a key theme of the talk.
Speaker's Career Progression:
C-5 pilot, instructor, flight examiner.
Attended Test Pilot School to combine operational experience with engineering education and judgment.
C-5 and C-17 external test pilot.
Pursued a Master's degree (University of Missouri, Rolla) in program engineering and engineering economics via distance learning, focusing on business case decisions in engineering.
Earned a Ph.D. (Texas A&M) in turbulence transition and flight research experiment design, applying advanced math/statistics to expensive flight data.
Served in the Air Force Research Laboratory (AFRL) in Aerospace Vehicles Division.
Deployed to Afghanistan for a year as an air advisor to the Afghan Air Force with a challenging mission of safety and sustainability efforts.
Worked in the Turbine Engine Division (internal, turbulent flow, chemistry, combustion).
Currently in High Speed Systems, focusing on hypersonics (speeds greater than ).
Hypersonics research involves accelerating from through transonic speeds up to and beyond ( to ), without typical reentry vehicle speeds where plasma sheaths significantly alter physics and communication.
Program Management: Manages technical programs to meet the triad of cost, schedule, and performance.
Emphasizes that altering one aspect (e.g., faster speed) affects the others (higher cost, potentially less performance).
Involved in professional organizations (AIAA Flight Test Technical Committee, Hypersonics Committee, Design-Build-Fly judge) and the Society of Experimental Test Pilots (over flight hours).
Personal Projects/Experiences Highlighted:
Flying a NASA F-18 for a Mars lander radar altimeter test, involving steep dives from to while pointing a pod straight down.
Flying a C-5, noting the spacious cockpit vs. an F-18 cockpit.
C-5M initial re-engineering test (new engines on an old aircraft), noting the huge test article.
C-17 mud characterization (testing slipperiness of mud on dirt fields).
F-16 senior project: Disrupting wake vortices (caused by a pod breaking off a ventral fin at ) using dual bimodal synthetic jet actuators to avoid needing a stiffer, heavier fin.
Dissertation work: Using an infrared camera to observe laminar-turbulent flow transition on an aluminum airfoil under controlled Reynolds numbers at .
Rules of Success (Humorous):
Keep the number of landings equal to the number of take-offs.
Never just fly in the same cockpit as someone greater than you.
After a good landing, you can walk away. After a great landing, the airplane can be used again.
Military Missions and Aerial Warfare
Air Force Mission Statement: "Fly, Fight, and Win in air and space and cyberspace."
The "fight" aspect is the reason for the extensive investment.
Budget: U.S. taxpayers provide approximately annually to the Air Force, with allocated to the AFRL for research.
Areas of Aerial Warfare:
Strike: Air-to-ground attack.
Air Superiority: Striking things in the air; ensuring freedom to operate in desired airspace (offensive and defensive).
Logistics: Carrying cargo, soldiers, or providing humanitarian aid and diplomatic support (e.g., presidential support like Marine One airlifted for overseas visits).
Reconnaissance: Gathering data/intelligence. The first U.S. military air warfare mission used hydrogen balloons for reconnaissance during the Civil War to gain "high ground" tactical advantage. The ultimate high ground is space.
Aircraft Designations (US Military System):
C: Cargo/Airlifter (e.g., C-5, C-17, C-130)
KC: Tanker/Cargo (e.g., KC-10, KC-46, KC-135)
B: Bomber (e.g., B-1, B-2, B-52)
F: Fighter (e.g., F-16, F-22, F-35)
R: Reconnaissance (often with another letter, e.g., RQ-4)
T: Trainer (e.g., T-37, T-1, T-38)
X: Test/Research (e.g., X-15, X-29)
M: Special Operations (e.g., MC-130)
E: Command and Control/Electronic Warfare (e.g., E-3 AWACS, EC-130)
L: Laser (e.g., YAL-1 Airborne Laser, retired due to cost despite effectiveness)
U: Utility (e.g., U-2)
A: Attack (e.g., A-10)
H: Search and Rescue (e.g., HC-130)
L (prefix): Cold Weather (e.g., LC-130 for snow runways in Antarctica)
V (prefix): VIP Transport (e.g., VC-25A, Air Force One)
W (prefix): Weather (e.g., WC-130 for hurricane hunting)
Q: Unmanned (drones)
V (suffix): Vertical Takeoff/Landing (e.g., F-35B)
Weapon Designations:
A: Air-launched (AIM-9, AIM-120)
G: Ground strike (e.g., from a silo or mobile launcher)
Payloads: The Reason for Design and Expenditure
Definition: A payload is "what you pay for"—the reason for building expensive systems.
Four Primary Payloads in Military Missions:
Weapons: For strike and air superiority.
Guns: Large caliber weapons like the A-10's GAU-8 Avenger (pictured against a Volkswagen for scale) designed to kill tanks, or the howitzer on an AC-130.
Bombs: e.g., MOAB (Massive Ordnance Air Blast), a penetrator bomb designed to destroy hardened targets, delivered by a B-2 bomber; JDAMs (GPS-guided bombs). Often maintained by dedicated ammo troops.
Missiles: Air-to-air (AIM-9, AIM-120 AMRAAM), ground attack (Hellfire), cruise missiles (often conventional, some nuclear capable), hypersonic glide vehicles.
Nuclear Triad: The U.S. maintains a balance of power through:
Air-launched weapons (B-52s, bombers).
Ground-launched weapons (Minuteman ICBMs from silos, each capable of independent targeting).
Sea-launched weapons (submarines, always on patrol, survivable).
Fighter Weapon Loadouts: Modern fighters like the F/A-18 and F-16 carry extensive weapon loads (AMRAAMs, AIM-9s, AGM-88 HARMs) on multiple missile stations. Stealth fighters (F-22, F-35) carry weapons internally to maintain low observability, requiring "loyal wingman" drones for external loadouts.
Sensors: Crucial for targeting and battle awareness.
Fighter Radars: Often determine the frontal area and shape of a fighter (e.g., F-22). The A-10 is an exception, built around its gun.
AWACS: The E-3 AWACS carries a massive revolving radar dome, providing an overhead battle picture beyond the Earth's curvature.
Defensive Sensors: Pods with lasers to shoot down incoming Surface-to-Air Missiles (SAMs).
U-2 Dragon Lady: A high-altitude, single-engine glider designed as a "flying sensor platform" with interchangeable nose, dorsal, and back sensors.
RQ-4 Global Hawk: Unmanned reconnaissance aircraft with extremely long endurance () and huge wings, often equipped with a parabolic antenna for satellite data downlink.
Troops and Supplies: For logistics and humanitarian missions.
Strategic Brigade Airdrop: C-17s drop paratroopers behind enemy lines, offering a solution to static warfare like WWI trenches.
Cargo: C-5s and C-17s transport tanks, trucks, supplies, and even specialized boats (e.g., Mark V Special Operations Craft).
Humanitarian Airlift: Examples include C-208s for medevac in Afghanistan, C-17s transporting mobile nursing homes after floods, and evacuating people from Kabul. Also, delivering generators (size of semi-trucks) to Guam after typhoons.
Unusual Cargo: C-5s have been used to air-drop ballistic missiles for testing, demonstrating the capability to launch ICBMs from anywhere a C-5 can fly, adding complexity to adversary targeting solutions and bolstering the nuclear triad.
Aircraft Design Principles and Examples
Bombers: Designed to carry a large payload of bombs over long distances.
B-52 Stratofortress: Features rotary launchers for efficient bomb deployment.
B-1 Lancer: Designed for low-altitude penetration, utilizing parachutes on bombs to allow the aircraft to escape shrapnel after a low-level drop.
B-2 Spirit: A stealth bomber; U.S. is the only operator. It's expensive (approx. per aircraft), with only currently operational (two crashed: one in Guam due to ice on static ports, another at Whiteman AFB due to hydraulic failure).
Stealth Design: Achieved by reflecting radar signatures away from the source dish (e.g., using angles, as radar comes in at and reflects at to the source, to redirect it elsewhere). Materials also absorb radar energy. Heat signatures are minimized by cooling exhaust.
Countermeasures to Stealth: Bi-static radar (placing receivers in multiple locations to catch deflected signals), infrared detection, satellite imagery.
B-21 Raider: The next-generation stealth bomber, replacing the B-2.
F-117 Nighthawk (Stealth Fighter) vs. B-2 Spirit: Both designed for stealth, but the F-117 (1970s) used flat panels due to limited computational power, while the B-2 (later generation) used continuous curves made possible by advanced supercomputers.
Engineer's Role: Focus on first principles (e.g., how radar works) and the computational tools needed to solve design problems, understanding their limitations to interpret results with engineering judgment.
Adversary Bombers: Tu-160 "Blackjack" (Russia), Tu-95 "Bear" (Russia, propeller-driven), H-6 (China). Similar solutions to similar design problems (small fuselage for parasite drag, large wings for efficiency).
Fighters: Designed for air combat, speed, and maneuverability.
A-10 Warthog/Thunderbolt II: Built around its gun. Designed for "low and slow" ground attack with thick straight wings. Engines are mounted externally and far apart for survivability against ground fire. The pilot sits in an armored titanium "bathtub" for protection. Twin tails provide redundancy (e.g., Captain Kim Campbell's A-10 surviving hydraulic damage).
F-22 Raptor: The world's best air superiority fighter. Features thrust vectoring (nozzles that can redirect engine thrust) for extreme maneuverability and large engines for supersonic flight without afterburners, greatly reducing fuel consumption.
F-35 Lightning II: Multi-role stealth fighter.
F-35A: Air Force variant.
F-35B: Marine Corps variant with a lift fan for Short Takeoff/Vertical Landing (STOVL).
Collaborative Combat Aircraft (CCA) / Loyal Wingman (e.g., XQ-58A Valkyrie, YF-Q-44A Anvil): Drones designed to fly with stealth fighters to carry external weapons (since external weapons compromise stealth) or additional sensors, enhancing mass and capability.
Other Fighters: F-15 (E-model, two engines), Eurofighter Typhoon (single engine, chin-mounted inlet), F/A-18 Hornet/Super Hornet (G-model "Growler" for electronic warfare with dedicated second naval flight officer), F-16 Falcon (lightweight fighter, often with conformal fuel tanks).
Adversary Fighters: J-20 (China), Su-35/Su-37 (Russia).
Internal Packing Challenges: Modern fighters are extremely cramped inside, filled with weapons, fuel, and electronics, leading to significant heat management problems. Solutions include using bleed air or fuel as a heat sink, sometimes requiring "soft cryogenics" to cool fuel.
F-22 Internal Weapons Bays: Can carry six AMRAAMs and two AIM-9s, which pop out from the stealth platform before launch.
Airlift/Mobility Platforms:
C-5 Galaxy: The largest U.S. military transport, capable of carrying massive loads.
C-17 Globemaster III: Capable of landing on dirt/mud fields. Can perform "strategic brigade airdrop" with six-ship formations using data links for spacing.
Helicopters: E.g., multiple-rotor aircraft for heavy lift (carrying Jeeps).
C-130 Hercules: Highly versatile, configurable for various missions:
LC-130: Cold weather operations (skis) to land on snow/ice.
HC-130: Search and Rescue.
AC-130: Gunship (with large artillery).
WC-130: Weather reconnaissance/hurricane hunting.
eVTOL (Electric Vertical Takeoff and Landing): e.g., Joby S3, potential for air taxis in urban environments.
E-2 Hawkeye: Carrier-borne early warning aircraft.
VC-25A (Air Force One): VIP transport for diplomatic missions (President, Vice President), often a modified Boeing 747.
H-3 (Marine One): Presidential helicopter.
Tankers: KC-10, KC-46, KC-135 combine tanker and airlift capabilities.
Reconnaissance Aircraft:
SR-71 Blackbird: Mach 3 reconnaissance aircraft, made of titanium, designed to operate at extreme temperatures and speeds. Daughter's second favorite airplane.
RQ-4 Global Hawk: Unmanned, high-altitude, long-endurance (HALE) platform, essentially a massive glider with a parabolic antenna for satellite communication.
Special Operations/Command & Control: MC-130 (special ops), EC-130 (electronic warfare and command/control with large antennas).
Trainers: T-37, T-1, T-38.
Test and Research ("X"-Planes)
X-15: The last reusable hypersonic aircraft (), representing the first peak of hypersonic research.
Quiet Supersonic Transport: X-plane designed to shape sonic boom to be undetectable on the ground, enabling overland supersonic flight.
X-29: Forward-swept wing aircraft, explored aeroelastic challenges despite theoretical aerodynamic advantages.
Variable Stability Simulator: An F-16 modified to handle like any desired aircraft, allowing test pilots to evaluate flight characteristics safely (e.g., simulating an F-104).
XV-70 Valkyrie: Mach 3 bomber. Only one remains at the Air Force Museum (another crashed during a photoshoot after an F-104 got caught in its wingtip vortex).
Hypersonic Test Vehicles:
X-51 WaveRider: Scramjet demonstrator achieving with hydrocarbon fuel (booster gets it to then scramjet ignites).
X-43 Hyper-X: Scramjet demonstrator achieving with hydrogen fuel.
Crucial Insight: The payload for test and research aircraft is data. This data, though expensive to collect, is invaluable for future designs.
Acquisition Life Cycle and Cost Implications
Life Cycle Stages: Planning, design, construction (production), operation, end-of-life.
Cost Drivers: Decisions made very early in the planning and design phases have profound and lasting cost consequences, with the majority of actual costs occurring during the operational phase.
Example: B-52s designed in the are projected to fly for , meaning early design decisions continue to dictate costs for a century.
Program Management Triad: Managers balance cost, schedule, and performance.
Changes to one aspect (e.g., demanding higher performance) will inevitably impact the others (e.g., higher cost and longer schedule).
Future of Aviation and Collaboration
Impact of AI on Aviation:
Pilot Roles: While commercial pilots will likely remain (perhaps with one pilot monitoring AI), combat aviation might see pilots phased out in the next generation.
Data Analysis: AI is excellent for processing vast amounts of data, establishing rule sets, and reducing the "toil" of analysis. This is particularly valuable for expensive hypersonic flight data.
Design: AI can generate initial designs or concepts (e.g., generating an image of a hypersonic aircraft).
Commercial Hypersonic Transport: While theoretically possible, its high cost makes widespread commercial viability a long-term prospect. Rocket cargo (exoatmospheric travel) might be a more near-term option for rapid transport.
Collaboration Between Soldiers and Scientists:
Dr. Von Kármán's principle in practice: The speaker's AFRL division consists of 8 ext{%} military personnel and 92 ext{%} civilians (of whom 60-65 ext{%} hold PhDs).
Roles: Military personnel interpret mission sets for civilian scientists/engineers; civilians provide deep subject matter expertise. This collaboration helps "burn down technical risk" by informing research programs to better understand uncertainties.
Military vs. Commercial Flying Career:
Military: Perceived as more challenging with varied missions, offering more opportunities for test pilot roles.
Commercial: Equal expertise required, but different demands. A personal decision to stay military was based on family lifestyle, allowing weekends and holidays at home, compared to the typically junior-level commercial pilot schedule requiring work on those days.