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<blockquote data-quote="TomS" data-source="post: 59912" data-attributes="member: 1484"><blockquote data-quote="TinWing">ATG has apparently been defunct since 2007.The HDI concept dates from 2004, and unsurprisingly, the website has long since gone offline.Has anyone retained any information?</blockquote>Recovered from Archive.org, this is the information on the HDI that was on the avtechgroup.org website as of May 2002:<blockquote>Homeland Defense InterceptorJavelin-HDI SpecificationsCruise Speed:&nbsp; &nbsp;&nbsp; Mach 0.92Top Speed:&nbsp; &nbsp;&nbsp; Mach 1.6Loiter Time:&nbsp; &nbsp;&nbsp; 3+ hours, air refueling capableRange:&nbsp; &nbsp;&nbsp; 1,500 nmRate of Climb:&nbsp; &nbsp;&nbsp; 36,000+ fpmCombat Ceiling:&nbsp; &nbsp;&nbsp; above 51,000 ftArmament:&nbsp; &nbsp;&nbsp; 2 Air-to-air missiles &amp; minigun (with tracers)Proposed Technical Approach: The Javelin Interceptor, or Homeland Defense Interceptor (HDI),&nbsp; is a derivative of the Javelin aircraft.&nbsp; The Javelin aircraft is currently undergoing development for FAR 23 certification. The Javelin would modified to meet the requirements of the Interceptor mission.&nbsp; The Javelin has already undergone extensive wind tunnel and computational fluid dynamics (CFD) development for low speed and transonic regimes. The second round of wind tunnel tests are being scheduled and construction of a full-scale mock-up has begun.&nbsp; In 2003, the first Javelin prototype will be assembled and flown. Operational Capability: The Javelin HDI will provide an inexpensive, low cost surveillance and interceptor aircraft to provide for homeland security against airborne terrorist threats. The&nbsp; HDI has a long loiter time, long range, high speed cruise, high altitude operations, and sophisticated data link capabilities for coordination with both airborne and ground based targeting assets. The&nbsp; HDI will relieve other more expensive to operate fighter/interceptor aircraft (such as F-16 &amp; F-15) to be used to defend against more comparable military adversaries. The&nbsp; HDI can provide combat air patrol (CAP), airborne interdiction, and surveillance against airborne assets that do not require the expensive and advanced tactical aircraft listed above.&nbsp; Rough Order of Magnitude Cost and Schedule: The&nbsp; HDI prototype could be available for evaluation as soon as 18-24 months from funding.&nbsp; The base unit cost of the HDI is estimated at $4.5M (US 2002 dollars) depending on engine and military equipment requirements. Airspace Sovereignty &amp; Threat BackgroundThe threat to US airspace sovereignty consists primarily of unconventional and asymmetric air attack methods by terrorists willing to commit suicide to achieve their objective. The US is well-equipped to defend against conventional military air threats.&nbsp; Conventional military attacks typically include warning through intelligence or other means.&nbsp; In contrast, terrorist cells are difficult to detect and infiltrate, are less predictable and therefore their attacks are difficult to prevent.Terrorist targets tend to be visible symbols of Western power or civilization.&nbsp; Target selection criteria include maximum number of casualties, symbolic impact as well as disruptive effectiveness.&nbsp; Examples include the White House, US Capitol, Pentagon, major sports event, theme park (Disney World), Empire State Building, Sears Tower, Washington Monument, any major airport terminal, port, nuclear plants, large hydroelectric dam, Wall Street or other similar location.Timing of an attack may coincide with Islamic religious holiday or other terrorist day of historic significance.&nbsp; Western holidays including New Years or July 4th may also have heightened risk.Means of attack include non-military aircraft resources that are either bought, stolen, hijacked or commandeered.&nbsp; Military components of the attack are furnished by supporting nations or groups and include training, equipment, firearms, agents and explosives.&nbsp; The primary delivery method is by airliners, business jets, certain larger turboprop or recip twins. These may be used with or without an additional bomb or agent to ‘enhance’ the attack on a target.&nbsp; Ag planes could also be used for an attack disbursing chemical or biological agent.Air threats may, but need not originate within US airspace.&nbsp; While the terrorist will delay or conceal themselves as long as possible, they will eventually exhibit unusual or threat behavior that is detectable.&nbsp; Depending on how the target is situated relative to the attack, there is a period of time to detect and analyze the threat behavior.&nbsp; The type of defensive resources appropriate to specific targets or general target areas can then be deployed against the potential threat(s).A highly visible, integrated air defense acts as a deterrent and aids in aspects of assuring the public of air travel safety.&nbsp; Persistent surveillance through space-based systems or advanced ground-based radar systems can increase the time to react and therefore the probability of defeating an attack.&nbsp; Detection and reaction time is also reduced with forward interceptor deployment and airborne patrols.&nbsp; Depending on how the potential target is situated, most areas of interest can be satisfactorily protected by alert or airborne interceptor assets capable of quick alert, high intercept speeds and lethal force to confront or eliminate the threat within a very few minutes.&nbsp; Certain high value, highly vulnerable targets of national interest will also require ground-based, point defense.&nbsp; Therefore, key interceptor requirements include low cost, surveillance assisted, high speed intercept.&nbsp; Armor plating, EMP protection, counter-countermeasures, high-rate 9G agility and survivability factors such as self-sealing tanks are not needed.&nbsp;&nbsp; Javelin Interceptor DescriptionThe Javelin Interceptor, or “Homeland Defense Interceptor,” (HDI) will provide a high performance economic interceptor, CAP and surveillance platform for homeland security against airborne threats of various types, including airliners, business jets, turboprop, recip twins or other general aviation aircraft, helicopters and Ag planes.The HDI is an all metal, single-seat, high-speed light military jet, capable of all weather, day, night, VFR or IFR intercepts.&nbsp; A two-seat version of the HDI is available for training, SAR and utility requirements.The Mach 1.6 HDI will be equipped with air-to-air radar and FLIR or IRST, secure military radios, including JTIDS datalink, IFF, NVG, night spotlight, laser, 7.62 mm minigun with tracer rounds, and two short-range heat seeking missiles.Interceptor MTGW is 6,500 lbs.Two GE J-85 variants or upgraded Williams International FJ44 engines with afterburning will power the HDI providing 8,000 lbs thrust total.&nbsp; Static intercept mission MTGW thrust to weight ratio is greater than 1.0 to 1.0, providing exceptional performance. Base GE-J85 or FJ44 test engines can be available for the HDI within 18-24 months of funding.&nbsp; Full capability FJ44 test engines with afterburning could be available 24 months from funding.Base cost of the HDI is $4.5 million per ship depending on specified equipment.&nbsp; The F-16 base unit cost is $26.9 million.&nbsp; HDI fuel and related cost is approximately $700 per flight hour, in contrast to $3,600 per flight hour for the F-16.&nbsp; Further the HDI is highly supportable, utilizing commercial-off-the-shelf equipment, allowing minimal deployment expense when compared to an F-16. Phase 1 is concept study and prototype, approximately $20 million (ATG funding only-engine &amp; military systems are separate line items) and 20 months in duration.The HDI is a derivative of the civilian Javelin executive jet which will be certified to FAR Part 23, aerobatic category, and single pilot operations.&nbsp; The aircraft will be certified for day, night, VFR, IFR and flight into known icing conditions.&nbsp;Javelin HDI Technical SpecificationsOverall Length 35.5 ft.&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp; (10.82 m.)Overall Height 10.5 ft.&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp; (3.20 m.)Overall Width 20.0 ft.&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp; (6.10 m.)Wing&nbsp; &nbsp; Span 20.0 ft.&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp; (6.10 m.)&nbsp; &nbsp; Sweep (@ ¼ chord) 33.2 degrees&nbsp; &nbsp; Area 100.0 sq. ft.&nbsp; &nbsp; &nbsp; &nbsp;&nbsp; (9.29 sq. m.)&nbsp; &nbsp; Aspect Ratio 4&nbsp; &nbsp; Mean Aerodynamic Chord (MAC) 5.91 ft.&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp; (0.49 m.)&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; Taper 0.15Horizontal Tail&nbsp; &nbsp; Span 14.0 ft.&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp; (4.27 m.)&nbsp; &nbsp; Sweep (@ ¼ chord) 37.0 degrees&nbsp; &nbsp; Area 35.0 sq. f.t.&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; (3.25 sq. m.)&nbsp; &nbsp; Aspect Ratio 5.80&nbsp; &nbsp; Mean Aerodynamic Chord (MAC) 2.72 ft&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp; (0.83 m)Vertical Tail&nbsp; &nbsp; Span 5.3&nbsp; ft.&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; (1.62 m)&nbsp; &nbsp; Sweep (@ ¼ chord) 41.0 degrees&nbsp; &nbsp; Area 42.6 sq. ft.&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp; (5.11 sq. m.)&nbsp; &nbsp; Cant 25.0 degreesWeights&nbsp; &nbsp; Maximum Ramp weight 6,500 lbs.&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; Empty Weight 2,950 lbs.&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; Maximum Fuel 3,300 lbs.&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; (490 gal.)&nbsp; &nbsp; &nbsp; &nbsp; Pilot&nbsp; 200 lbs.&nbsp; &nbsp; &nbsp; &nbsp; Missiles &amp; System (2 @ 12.5 lbs ea)&nbsp; &nbsp;&nbsp; 50 lbs.Options &nbsp; &nbsp; Centerline hard-point weight limit&nbsp;&nbsp; 500 lbs.&nbsp; &nbsp; &nbsp; &nbsp; 7.62 mm Minigun &amp; Ammunition&nbsp; &nbsp; &nbsp;&nbsp; 50 lbs.The performance data provided below assume maximum take off weight (MTOW) and a standard day (ISA), sea level dry runway.&nbsp; &nbsp; &nbsp; Parameter&nbsp; &nbsp; &nbsp; &nbsp; FAR Part 23Take Off Distance&nbsp; &nbsp; 1,500 ft&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; Typical V2 Speeds (at MTOW) 125 kts&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; Landing Distance (at MTOW) less than 5,000 ftTypical Approach/Landing Speeds (at MTOW) 143 kts/110 kts (231 km/hr/194 km/hr)Stall Speed (landing config. at MTOW) 110 KCAS&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp; (176 km/hr)Rate of Climb, Two Engine 36,000+ fpm&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp; (10,976+ mpm)Combat Ceiling above 51,000&nbsp; ft&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp; (15,545 m)Cruising Speeds&nbsp; &nbsp; Normal Speed 0.92M / 528 kts / 608 mph / 976 kph&nbsp; &nbsp; Supersonic Dash 1.6 MachFerry Range 1,500 nm/1,700 sm/2,778 km Endurance&nbsp; &nbsp;&nbsp; High Altitude Loiter 3+ hours (air refueling capable)</blockquote>This strikes me as a fairly naive design.&nbsp; Based on their weight, the two air-to-air missiles have to be Stingers, but an actual Air-to-Air Stinger Launcher with two missiles weighs 100 pounds, not the 50 pounds cited here.&nbsp; And two Stingers would probably fail to reliably down an airliner.&nbsp; Likewise, the actual weight of a 7.62mm minigun installation would be several times the weight given -- a bare M134 weighs about 42 pounds, leaving only eight for mounting, ammunition, feed systems, etc.</blockquote>

[QUOTE="TomS, post: 59912, member: 1484"] [quote="TinWing"] ATG has apparently been defunct since 2007. The HDI concept dates from 2004, and unsurprisingly, the website has long since gone offline. Has anyone retained any information? [/quote] Recovered from Archive.org, this is the information on the HDI that was on the avtechgroup.org website as of May 2002: [quote][b]Homeland Defense Interceptor[/b] Javelin-HDI Specifications Cruise Speed: Mach 0.92 Top Speed: Mach 1.6 Loiter Time: 3+ hours, air refueling capable Range: 1,500 nm Rate of Climb: 36,000+ fpm Combat Ceiling: above 51,000 ft Armament: 2 Air-to-air missiles & minigun (with tracers) Proposed Technical Approach: The Javelin Interceptor, or Homeland Defense Interceptor (HDI), is a derivative of the Javelin aircraft. The Javelin aircraft is currently undergoing development for FAR 23 certification. The Javelin would modified to meet the requirements of the Interceptor mission. The Javelin has already undergone extensive wind tunnel and computational fluid dynamics (CFD) development for low speed and transonic regimes. The second round of wind tunnel tests are being scheduled and construction of a full-scale mock-up has begun. In 2003, the first Javelin prototype will be assembled and flown. Operational Capability: The Javelin HDI will provide an inexpensive, low cost surveillance and interceptor aircraft to provide for homeland security against airborne terrorist threats. The HDI has a long loiter time, long range, high speed cruise, high altitude operations, and sophisticated data link capabilities for coordination with both airborne and ground based targeting assets. The HDI will relieve other more expensive to operate fighter/interceptor aircraft (such as F-16 & F-15) to be used to defend against more comparable military adversaries. The HDI can provide combat air patrol (CAP), airborne interdiction, and surveillance against airborne assets that do not require the expensive and advanced tactical aircraft listed above. Rough Order of Magnitude Cost and Schedule: The HDI prototype could be available for evaluation as soon as 18-24 months from funding. The base unit cost of the HDI is estimated at $4.5M (US 2002 dollars) depending on engine and military equipment requirements. [b] Airspace Sovereignty & Threat Background[/b] The threat to US airspace sovereignty consists primarily of unconventional and asymmetric air attack methods by terrorists willing to commit suicide to achieve their objective. The US is well-equipped to defend against conventional military air threats. Conventional military attacks typically include warning through intelligence or other means. In contrast, terrorist cells are difficult to detect and infiltrate, are less predictable and therefore their attacks are difficult to prevent. Terrorist targets tend to be visible symbols of Western power or civilization. Target selection criteria include maximum number of casualties, symbolic impact as well as disruptive effectiveness. Examples include the White House, US Capitol, Pentagon, major sports event, theme park (Disney World), Empire State Building, Sears Tower, Washington Monument, any major airport terminal, port, nuclear plants, large hydroelectric dam, Wall Street or other similar location. Timing of an attack may coincide with Islamic religious holiday or other terrorist day of historic significance. Western holidays including New Years or July 4th may also have heightened risk. Means of attack include non-military aircraft resources that are either bought, stolen, hijacked or commandeered. Military components of the attack are furnished by supporting nations or groups and include training, equipment, firearms, agents and explosives. The primary delivery method is by airliners, business jets, certain larger turboprop or recip twins. These may be used with or without an additional bomb or agent to ‘enhance’ the attack on a target. Ag planes could also be used for an attack disbursing chemical or biological agent. Air threats may, but need not originate within US airspace. While the terrorist will delay or conceal themselves as long as possible, they will eventually exhibit unusual or threat behavior that is detectable. Depending on how the target is situated relative to the attack, there is a period of time to detect and analyze the threat behavior. The type of defensive resources appropriate to specific targets or general target areas can then be deployed against the potential threat(s). A highly visible, integrated air defense acts as a deterrent and aids in aspects of assuring the public of air travel safety. Persistent surveillance through space-based systems or advanced ground-based radar systems can increase the time to react and therefore the probability of defeating an attack. Detection and reaction time is also reduced with forward interceptor deployment and airborne patrols. Depending on how the potential target is situated, most areas of interest can be satisfactorily protected by alert or airborne interceptor assets capable of quick alert, high intercept speeds and lethal force to confront or eliminate the threat within a very few minutes. Certain high value, highly vulnerable targets of national interest will also require ground-based, point defense. Therefore, key interceptor requirements include low cost, surveillance assisted, high speed intercept. Armor plating, EMP protection, counter-countermeasures, high-rate 9G agility and survivability factors such as self-sealing tanks are not needed. [b] Javelin Interceptor Description[/b] The Javelin Interceptor, or “Homeland Defense Interceptor,” (HDI) will provide a high performance economic interceptor, CAP and surveillance platform for homeland security against airborne threats of various types, including airliners, business jets, turboprop, recip twins or other general aviation aircraft, helicopters and Ag planes. The HDI is an all metal, single-seat, high-speed light military jet, capable of all weather, day, night, VFR or IFR intercepts. A two-seat version of the HDI is available for training, SAR and utility requirements. The Mach 1.6 HDI will be equipped with air-to-air radar and FLIR or IRST, secure military radios, including JTIDS datalink, IFF, NVG, night spotlight, laser, 7.62 mm minigun with tracer rounds, and two short-range heat seeking missiles. Interceptor MTGW is 6,500 lbs. Two GE J-85 variants or upgraded Williams International FJ44 engines with afterburning will power the HDI providing 8,000 lbs thrust total. Static intercept mission MTGW thrust to weight ratio is greater than 1.0 to 1.0, providing exceptional performance. Base GE-J85 or FJ44 test engines can be available for the HDI within 18-24 months of funding. Full capability FJ44 test engines with afterburning could be available 24 months from funding. Base cost of the HDI is $4.5 million per ship depending on specified equipment. The F-16 base unit cost is $26.9 million. HDI fuel and related cost is approximately $700 per flight hour, in contrast to $3,600 per flight hour for the F-16. Further the HDI is highly supportable, utilizing commercial-off-the-shelf equipment, allowing minimal deployment expense when compared to an F-16. Phase 1 is concept study and prototype, approximately $20 million (ATG funding only-engine & military systems are separate line items) and 20 months in duration. The HDI is a derivative of the civilian Javelin executive jet which will be certified to FAR Part 23, aerobatic category, and single pilot operations. The aircraft will be certified for day, night, VFR, IFR and flight into known icing conditions. [b]Javelin HDI Technical Specifications[/b] Overall Length 35.5 ft. (10.82 m.) Overall Height 10.5 ft. (3.20 m.) Overall Width 20.0 ft. (6.10 m.) Wing Span 20.0 ft. (6.10 m.) Sweep (@ ¼ chord) 33.2 degrees Area 100.0 sq. ft. (9.29 sq. m.) Aspect Ratio 4 Mean Aerodynamic Chord (MAC) 5.91 ft. (0.49 m.) Taper 0.15 Horizontal Tail Span 14.0 ft. (4.27 m.) Sweep (@ ¼ chord) 37.0 degrees Area 35.0 sq. f.t. (3.25 sq. m.) Aspect Ratio 5.80 Mean Aerodynamic Chord (MAC) 2.72 ft (0.83 m) Vertical Tail Span 5.3 ft. (1.62 m) Sweep (@ ¼ chord) 41.0 degrees Area 42.6 sq. ft. (5.11 sq. m.) Cant 25.0 degrees Weights Maximum Ramp weight 6,500 lbs. Empty Weight 2,950 lbs. Maximum Fuel 3,300 lbs. (490 gal.) Pilot 200 lbs. Missiles & System (2 @ 12.5 lbs ea) 50 lbs. Options Centerline hard-point weight limit 500 lbs. 7.62 mm Minigun & Ammunition 50 lbs. The performance data provided below assume maximum take off weight (MTOW) and a standard day (ISA), sea level dry runway. Parameter FAR Part 23 Take Off Distance 1,500 ft Typical V2 Speeds (at MTOW) 125 kts Landing Distance (at MTOW) less than 5,000 ft Typical Approach/Landing Speeds (at MTOW) 143 kts/110 kts (231 km/hr/194 km/hr) Stall Speed (landing config. at MTOW) 110 KCAS (176 km/hr) Rate of Climb, Two Engine 36,000+ fpm (10,976+ mpm) Combat Ceiling above 51,000 ft (15,545 m) Cruising Speeds Normal Speed 0.92M / 528 kts / 608 mph / 976 kph Supersonic Dash 1.6 Mach Ferry Range 1,500 nm/1,700 sm/2,778 km Endurance High Altitude Loiter 3+ hours (air refueling capable) [/quote] This strikes me as a fairly naive design. Based on their weight, the two air-to-air missiles have to be Stingers, but an actual Air-to-Air Stinger Launcher with two missiles weighs 100 pounds, not the 50 pounds cited here. And two Stingers would probably fail to reliably down an airliner. Likewise, the actual weight of a 7.62mm minigun installation would be several times the weight given -- a bare M134 weighs about 42 pounds, leaving only eight for mounting, ammunition, feed systems, etc. [/QUOTE]

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