The team is confident the tiltrotor can safely refuel F/A-18s midair after conducting the first proximity test between the two last week.
A Hornet flew within 30 ft. of the MV-22’s drogue chute in a lateral offset position during an Aug. 29 flight trail, says Chad Sparks, advanced derivatives manager for Bell/Boeing. This was the fourth in a series of tests paid for by Bell/Boeing as the team examines alternative missions for the V-22.
The U.S. Marine Corps is the primary customer for the aircraft with a program of 360 aircraft, with the U.S. Air Force also buying 50 of the aircraft to replace its retired MH-53s. The team opted to sponsor the trials in hopes of capturing interest from one of its existing customers and to also whet the appetite of the Navy as it looks at alternatives to replace the aging C-2 Greyhound Carrier Onboard Delivery (COD) platform with 48 or more aircraft. The team is clearly trying to send the message that the Osprey will be a multi-mission option.
Whether that influences the shape of the competition remains to be proven. But, the cost of the Osprey has not dipped below $60 million as once hoped by the team and customers alike. The target price is $70 million in the next multiyear buy of Ospreys, in part owing to reduced production rate funded by the Pentagon. The team has a bevy of international prospects, but each is for only a handful of aircraft. So, the biggest tender yet to get remains capturing the interest of the U.S. Navy.
The team is hoping the U.S. Navy or Marine Corps will provide funding for additional testing to include contact between the refueler and receiver and, eventually, passage of fuel between the two, says Ken Karika, business development manager for the Bell/Boeing team.
The industry team had looked at the concept of using the V-22 as an aerial refueler for years but the effort gained steam – and funding from corporate partners – at the beginning of the year, Sparks says. Prior to last week’s flight, the company validated the ability to extend and retract the refueling hose and drogue, a Cobham model also used by the Marine Corps’ KC-130 fleet. Also prior to the proximity flight, the team collected data on the behavior of the Hornet in the MV-22’s wake. “Pilots didn’t report any significant wake turbulence,” Sparks said, noting the feedback validated expectations based on prior modeling and earlier input from the pilot of a Cessna surrogate used to study the MV-22’s wake.
During the Aug. 29 test, the two aircraft were traveling at 210 kt. The high-speed version of the hose/drogue refueling system is designed to be deployed at 185 kt. and function at up to 250 kt., Sparks says.
For that test, the V-22 was functioning in airplane mode. Sparks says the company prioritized testing for the Hornet specifically to address concerns that the Pentagon could need more refuelers for high-speed receivers. The Osprey could be used – like the KC-130 – as a refueler for rotary wing aircraft, as well.
A preliminary test is slated for next week, Sparks says. Officials will extend and retract the hose and conduct low-speed proximity tests with no contact between the refueler and receiver.
Rotary wing refueling will require a separate drogue used specifically by helicopters and Sparks says the target is to operate around 105 kt.,with the aircraft in helicopter mode operating with a partially converted nacelle.
The refueling system makes use of onboard tanks as well as a roll-on/roll-off bladder, Sparks says. The hose extends 90 ft., about 80 ft. from the end of the ramp of the MV-22. The operator must open the ramp to extend the refueling hose; once extended, the ramp is then raised back up with the top ramp door left open, Sparks says.
Depending on mission profile, the system can offload up to 12,000 lb. of fuel, Karika says.
The prototype design, used for last week’s test, included a refueling system operator station near the ramp, but Karika says this can be placed where the customer requires.
The aerial refueling concept grew out of technical work done for Marine operators to use the Osprey as a ground-based refueler for helicopters and vehicles. That concept was fielded in 2007 to support operations in Iraq.
Editor's note: This post was changed to correct the designation of the receiver aircraft Sept. 4.