The A10 Thunderbolt II by Andy Ko February

The A-10 Thunderbolt II by Andy Ko February 11, 2000 http: //www. geocities. com/Cape. Canaveral/Hall/5777/A-10. html

History • Lessons learned from Korea and Vietnam War – Need for close air support – Model the A-1 Skyraider • AX Program – June 1966 • USAF send RFP to 21 companies • Parallel Paid Study Contract http: //skyraider. org/skyassn/otherpics/mignard/602 sos. htm – 1970 - Requirements finalized, bidding starts • Northtrop & Fairchild Republic selected for fly-off – 1972 - Fly-off begins – Jan 1973 - Fairchild’s A-10 announced to be the winner

Requirements • Speed: 350 -400 kts. • 250 nm. operational radius with: – 9500 lbs external stores and internal ammunition • Field Length = 4000 ft. at Max TOGW • Simplicity – Only proven/off-the-shelf technology – Exception: High BPR turbofans • Survivability – Redundancy • Cheap – $3. 02 Million (F-16 , F-18, Harrier) • F-16, $9. 5 - $12. 8 Million • F-18, $24 Million • AV-8 B, $23. 7 Million http: //www. af. mil/news/factsheets/A_10_OA_10_Thunderbolt_II. html

Dimensions Wing span Length overall Height overall Weights Operating empty Basic design weight Internal fuel Max external load Performance 57 ft 6 in 53 ft 4 in 14 ft 8 in 24959 lbs 30384 lbs 10700 lbs 16000 lbs Take-off weights Maximum CAS mission Anti-armour mission Ferry Graphics from Dana Bell, “A-10 Warthog in detail & Scale”, 50000 lbs 47094 lbs 42071 lbs 49774 lbs Never-exceed speed Max level speed at sea level, clean Combat speed at 5000 ft with six Mk 82 bombs Cruising speed at sea level Sea-level rate of climb at design weight Service ceiling Combat radii Anti-armour configuration, 30 min combat, 40 nm penetration and exit CAS configuration, 1. 88 hr single-engine loiter at 5000 ft, 10 min combat Ferry range, 50 kt headwinds, 20 min reserve 450 kts 381 kts 380 kts 300 kts 6000 ft/min 45000 ft 252 nm 250 nm 2240 nm

Configuration • Cantilever Low wing • Airfoils – NACA 6716 on centerline, NACA 6713 at tip – Provides low wing loading (92. 14 lb/sq ft) • Wide Chords – Mean wing chord = 8 ft 11. 32 in • 2 segment, 3 position Fowler flaps – No leading edge devices • Wide span ailerons – Dual upper and lower surfaces for airbrakes – SAS (Stability Augmentation System) • H-Tail – No deep stall – Spin resistance Graphics from Dana Bell, “A-10 Warthog in detail & Scale”,

Configuration (Cont’d) • Little Sweep – Mach number no greater than 0. 68 • Aspect Ratio = 6. 54 • Taper ratio = 0. 65 • Engines – – TF 34 -GE-100 (6. 2 BPR) 9065 lbs. Static thrust Turbofan vs. Turboprop vs. Turbojet? Placement http: //www. a-10. org/photos 5. html • Nozzles are canted 9º upward • Landing Gear – Forward retracting – Exposed wheels when retracted http: //www. a-10. org/photos 6. html

Improvements / Fixes • Stall problem – Initially a fixed slat was installed, later changed to a movable slat – Stall strip added to the leading edge – Wing root modified with a fillet – Forward projecting strakes • Drag improvements – Increased wing-span by 30 in. – Hoerner wingtips http: //www. a-10. org/photos 7. html • Induced drag • Aileron effectiveness – Canopy and windscreen shapes refined – Pylons shortened and streamlined – Reduced landing gear pod cross section http: //www. a-10. org/photos. html

Comparison with other Attack Aircraft * With combat load ** With external fuel tanks (tanks retained)

Survivability and Lethality • Redundant control system – 2 hydraulic controls (separated) and 1 cable manual reversion – H-tail provides 2 separated control surfaces • Redundant structure • Titanium bathtub for pilot – 1. 5 in thick bulletproof canopy • Weapon loads – GAU-8/A Avenger 30 mm seven barrel gun • 1350 rounds at 2100 or 4200 rounds/min – 11 store pylons with max external load of 16000 lbs Smithsonian Air & Space Magazine, March 1999, pg 27