Armed Aerial Scout competition draws 7 hopefuls

AgustaWestland, AVX, Bell, Boeing, Eurocopter, MD and Sikorsky look to win US Army's AAS award for up to 368 new helicopters to replace Bell's OH58D Kiowa Warrior.

A bridge to somewhere

On Apr 30, 2013, the 1st OH­58F —featuring the CASUP modification—flew at Redstone Arsenal in Huntsville AL. The Army, in partnership with Bell Helicopter, plans to convert all Kiowa Warrior aircraft to the F model at about $5 million apiece.

Most of the development work was completed at Redstone. This fall, all of the systems integration and production work will be transferred to Corpus Christi Army Depot in Texas—a move that reduces overall program costs. The aircraft could enter low rate production in 2015 and be fielded to units by 2016.

The most noticeable external change in the OH58F is the removal of the cold-war-inspired mast-mounted sensor ball above the rotor system. A new nose-mounted Raytheon sensor pod includes improved optics, an infrared sensor, laser pointer and laser spot tracker.

The CASUP upgrade also includes a new digital cockpit that doubles the processing speed to the aircraft, gives it the ability to operate at Level II manned–unmanned operations (MUM-O) and reduces the empty weight by 160 lbs.

The US Army has a long history with the Kiowa. Ideally, it would like to operate 368 aircraft, but through battle damage and combat attrition this number has dropped to 329. A total of 42 aircraft are currently being refurbished through the combat replacement program at a rate of 1 aircraft per month.

Bell OH58 Block II

Bell OH58 Block II adds new 1000-shp Honeywell HTS900 turboshaft engine, rotors and transmission from the Bell 407 that would give it more speed and better hot-and-high capability than the current OH58D Kiowa Warrior (above).

Bell is confident that the OH58 series will operate in the scout configuration for at least the next 20 years. Based originally on the Bell 206, the OH58 series has flown over 820,000 combat hours and routinely achieves a mission capable rate of over 90%. The service has flown the OH58A, C, D and now F model.

In Oct 2012, Bell demonstrated the new Block II OH58 Kiowa Warrior to the Army. Block II aircraft are equipped with a 1000-shp Honeywell HTS900 turboshaft, the rotors and transmission from the Bell 407, and the tail from the Bell 427. Block II modifications should allow the helicopter to hover in 6K/95 conditions.

Bell has incorporated an incremental upgrade strategy for the OH­58. If acquired by the Army, the Block II standard would eventually be upgraded to the Block III model, which would be more powerful and have a new rotor system.

AVX Aircraft—OH58F AVX SLEP kit

AVX is a concept helicopter based on the Bell OH58F but with a new coaxial counter-rotating rotor system and aft-located dual ducted fans. AVX Program Mgr Steven Webster claims a 30-kt speed increase and 20% fuel reduction compared with the current OH58F.

Founded in 2005, AVX Aircraft has fielded an AAS solution which combines the Army's current OH58F upgrade with a SLEP kit that exceeds the capabilities of the remaining JROC performance gaps. According to AVX Program Mgr Steven Webster, "The AVX technology solution with the US Army CASUP upgrade [OH­58F] closes the capability gaps identified in the Jul 2009 JROC [recommendations]."

The AVX kit replaces the original OH58D/F rotor system and tail boom structure with coaxial counter-rotating rotors and aft-located dual ducted fans.

AVX's unique patented technology offers several advantages over conventional designs. Since the main rotors are needed only for lift, the aircraft is able to fly level, resulting in less drag than a conventional rotorcraft.

The rear fans act like propellers and provide 30–50% greater speed, fuel savings of 20–30% and improved directional control. Applied to the OH58F airframe, the AVX kit will increase speed by 30 kts and reduce fuel consumption by 20%.

In addition to increased performance and reduced costs, the AVX configuration increases safety by improving the OH58F's autorotation characteristics. It also has the potential to reduce brownout conditions in the landing configuration.

(A degraded visual environment [DVE] is a serious threat to rotorcraft safety.) Webster adds, "The AVX technology solution addresses the DVE challenge where the aft fans can be used to decelerate, eliminating the need to flare and thereby allowing a nose-down landing with better visual awareness."

AgustaWestland AW169 AAS

AgustaWestland AW169 AAS is an advanced twin-engine machine powered by 2 PW210A engines with FADEC rated at 1000 shp each. Top speed is 140 kts. It is a smaller and faster helicopter based on the successful AW139.

Another AAS contender, AgustaWestland, flew its AW139M technology demonstrator for the Army in Jun 2012. The company now proposes a new military variant—the AW169 AAS.

Unveiled at the 2013 Army Aviation Assn of America Annual Meeting in Fort Worth TX, the AW­169 AAS is an advanced twin-engine aircraft with the capability to meet all AAS mission requirements and providing a new-design, new-technology helicopter for the current and future battlefield.

The AW169 is a clean sheet design unveiled at the 2010 Farnborough Airshow. First flight followed in May 2012 with basic civil certification scheduled for 2014. Two advanced PW210A engines (rated at 1000 shp each) with FADEC and a highly efficient rotor system will allow the AW169 AAS to operate in challenging hot-and-high conditions. Top speed is listed as 140 kts.


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