The A-10 Thunderbolt IIby Andy Ko

February 11, 2000

http://www.geocities.com/CapeCanaveral/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

– 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

http://skyraider.org/skyassn/otherpics/mignard/602sos/602sos.htm

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-8B, $23.7 Million

http://www.af.mil/news/factsheets/A_10_OA_10_Thunderbolt_II.html

Graphics from Dana Bell, “A-10 Warthog in detail & Scale”,

DimensionsWing span 57ft 6inLength overall 53ft 4inHeight overall 14ft 8in

WeightsOperating empty 24959lbsBasic design weight 30384lbsInternal fuel 10700lbsMax external load 16000lbs

Take-off weightsMaximum 50000lbsCAS mission 47094lbsAnti-armour mission 42071lbsFerry 49774lbs

Never-exceed speed 450ktsMax level speed at sea level, clean 381ktsCombat speed at 5000ft with six 380ktsMk82 bombsCruising speed at sea level 300ktsSea-level rate of climb at design weight 6000ft/minService ceiling 45000ft

Anti-armour configuration, 30min combat, 252nm40nm penetration and exitCAS configuration, 1.88hr single-engine 250nmloiter at 5000ft, 10min combatFerry range, 50kt headwinds, 2240nm 20 min reserve

Performance

Combat radii

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 = 8ft 11.32in

• 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

– TF34-GE-100 (6.2 BPR)

– 9065 lbs. Static thrust– Turbofan vs. Turboprop vs. Turbojet?

– Placement• Nozzles are canted 9º upward

• Landing Gear– Forward retracting

– Exposed wheels when retracted

http://www.a-10.org/photos/photos6.html

http://www.a-10.org/photos/photos5.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• 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/photos7.html

http://www.a-10.org/photos/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 30mm 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