Civil tiltrotor resumes flight test

[Lee]

After a two year delay, the BA-609 has resumed test flights...


"Bell/Agusta test pilots reaching milestones on BA609 flights
Fort Worth Star Telegram 06/16/05
author: Bob Cox
Copyright 2005

Test pilots for Bell/Agusta Aerospace Co. have begun the long process of flight tests on the BA609 aircraft, the long-awaited tilt-rotor aircraft that Bell Helicopter hopes will find a lucrative niche in commercial aviation.

The plan, a Bell official said Wednesday, is to finish the tests and have the BA609 certified for delivery to customers by late 2008.

Test pilots achieved a significant milestone during a test flight Monday at Arlington Municipal Airport, when pilots rotated the aircraft's twin engine-nacelles from 90 degrees, or vertical, to 60 degrees for increased forward flight speed and efficiency. The landing gear was retracted for the first time.

"Everything worked just like it was supposed to," said Don Barbour, a senior executive of Bell/Agusta, the joint venture of Fort Worth-based Bell and Italy's AgustaWestland.

Barbour is part of the Bell/Agusta contingent at the Paris Air Show this week.

During the next couple of weeks, he said, test officials plan to lower the nacelles to the 0 degree mark, parallel to the fuselage, for full forward flight capability.

The flight tests are being conducted at Bell's XworkX research and development facility at the Arlington airport.

"We're trying to go forward a little bit further each time," Barbour said.

Like its larger predecessor, the V-22 Osprey military transport, the BA609 can take off and land vertically like a helicopter and fly with the greater speed and range of an airplane.

The V-22 is undergoing an extensive round of tests that could lead to a Pentagon decision later this year to increase production.

The goal for the BA609 is 275 knots cruise speed, or nearly twice that of a conventional helicopter.

Bell/Agusta hopes the BA609, which will be able to carry six to nine passengers, will garner sales from customers who now use airplanes and helicopters.

The BA609 has been under development since 1998. The program has suffered at times from lack of development funds and attention, as Bell focused on resolving problems with the V-22.

A number of BA609 test flights were performed in March 2003, with the nacelles at or near 90 degrees for vertical flight.

Follow-up tests were to have occurred later in 2003 or 2004, but Barbour said the initial tests showed numerous changes needed to be made to the aircraft and the flight control software.

Barbour said the test program is event-driven, designed to meet specific objectives rather than a time schedule.

Most of the prospective customers who originally signed up to buy the BA609 are still waiting patiently, Barbour said, because they want the capabilities of the aircraft"

[poadeleted3]

Given the absolutely dismal record of the V-22, there's no chance I'd set foot on one of Bell's tilt rotors until they have a lot more years of trouble free service.

[Henning]

Originally Posted by Joe Williams

Given the absolutely dismal record of the V-22, there's no chance I'd set foot on one of Bell's tilt rotors until they have a lot more years of trouble free service.

I would, heck, I'd sign up for test pilot. This set of aircraft isn't Bell's first foray into the tilt rotor design, I had books when I was a kid with pictures of them. Most of the accidents that occurred were operational accidents rather than equipment failures, and the record isn't all that dismal if taken in the light of other military projects.

[Lee]

Originally Posted by Henning

I would, heck, I'd sign up for test pilot. This set of aircraft isn't Bell's first foray into the tilt rotor design, I had books when I was a kid with pictures of them. Most of the accidents that occurred were operational accidents rather than equipment failures, and the record isn't all that dismal if taken in the light of other military projects.

I would too. The V-22 has gotten a bad rap in the press, but I wouldn't call it's record dismal. Things are going very well with the program right now and the Marines are starting to rack up lots of flight hours. The 609 isn't nearly as complex as the V-22 and the operational requirements are much more benign.

[iGismo]

I think the tilt rotor concept and the V-22 Osprey can probably be as safe as any other helicopter, but it seems to require far more piloting skill than most.

The coaxial rotor helicopter OTOH, appears to solve much of the same problem (retreating blade stall) while retaining a more "helicopter like" operation. Here's Sikorsky's latest which I expect to be competition for the tilt-rotor:

http://www.gizmag.com/go/4117/

[Lee]

Originally Posted by lancefisher

I think the tilt rotor concept and the V-22 Osprey can probably be as safe as any other helicopter, but it seems to require far more piloting skill than most.

The coaxial rotor helicopter OTOH, appears to solve much of the same problem (retreating blade stall) while retaining a more "helicopter like" operation. Here's Sikorsky's latest which I expect to be competition for the tilt-rotor:

http://www.4lots.com/index.asp?PageA...WPROD&ProdID=8

I don't think it requires more skill, just more comprehensive training that includes fixed wing and vertical flight regimes.

And lance the link you posted is for a toolbox.

[poadeleted3]

Originally Posted by Nav8tor

I don't think it requires more skill, just more comprehensive training that includes fixed wing and vertical flight regimes.

And lance the link you posted is for a toolbox.

Hmmm, it took me to a portable power supply. But, I will guarantee that product does not suffer from retreating blade stall

[Dave Krall CFII SEL SES]

Originally Posted by Joe Williams

Given the absolutely dismal record of the V-22, there's no chance I'd set foot on one of Bell's tilt rotors until they have a lot more years of trouble free service.

One has to have a sense of adventure to test pilot at any level. It's a blast. I don't know the exact figures but, the prototypes and early models of so many new aircraft models have gone down that I've lost count, but can name many that have gone on to become certificated, one way or another.

[Lee]

Originally Posted by lancefisher

Here's Sikorsky's latest which I expect to be competition for the tilt-rotor:

Did you mean to post this link?

http://www.sikorsky.com/details/0,30...TI2088,00.html

[Dave Krall CFII SEL SES]

Originally Posted by Nav8tor

Did you mean to post this link?

http://www.sikorsky.com/details/0,30...TI2088,00.html

The X2 could work as is, but the pusher prop should be on the underside, with seats that pitch through 90 degrees so that speeds just under Mach 1 would be attainable. Otherwise, it will be just a much faster and more useful successor to the "Carter Copter" an auto-gyro machine more effectively employed at blowing Corvette engines than exceeding Mu.

[Lee]

Originally Posted by Dave Krall CFII

The X2 could work as is, but the pusher prop should be on the underside, with seats that pitch through 90 degrees so that speeds just under Mach 1 would be attainable. Otherwise, it will be just a much faster and more useful successor to the "Carter Copter" an auto-gyro machine more effectively employed at blowing Corvette engines than exceeding Mu.

I'm having difficulty visualizing the concept. How would putting the prop on the bottom make such a high speed possible?

[Dave Krall CFII SEL SES]

Originally Posted by Nav8tor

I'm having difficulty visualizing the concept. How would putting the prop on the bottom make such a high speed possible?

Actually, it would be just as well or even better to leave that prop off completely. Props were made to eat air head on like airplanes, not sidewise, to be efficient for speed.

[Dave Krall CFII SEL SES]

Originally Posted by Steve

Lockheed built a few high speed helicopter prototypes for the Army.

This one is parked in front of the Army Aviation Museum at Ft. (Mother) Rucker.



I think the top speed was around 210 kts.

And the choppers won't go too awful much faster than that until that big fan on the top gets pointed in the forward direction, at which point they can go up to just under Mach I.

[iGismo]

Originally Posted by Nav8tor

I don't think it requires more skill, just more comprehensive training that includes fixed wing and vertical flight regimes.

Seems to me that training would generate more skills in the pilots. And AFaIK the only issue with the increased training/skill level is the cost of obtaining it and maintaining it. I certainly didn't mean to imply that pilots can't be trained to operate a tilt rotor safely.

And lance the link you posted is for a toolbox.

Oops, actually that was a power supply that I posted in another thread where Ken I. suggested bringing a generator on a long flight to power a laptop.

Here's the link I meant to post:
http://www.gizmag.com/go/4117/

I also fixed the earlier post.

[iGismo]

Originally Posted by Nav8tor

Did you mean to post this link?

http://www.sikorsky.com/details/0,30...TI2088,00.html

That would do. It was indeed the X2 I was referring to.

[Lee]

Originally Posted by lancefisher

Seems to me that training would generate more skills in the pilots. ..

Point taken. By skills I thought you meant talent which I consider to be more of a natural ability. There's no question though that competent tiltrotor pilots will require more training (and thus additional skills) than fixed wing or helicopter pilots.

[Lee]

Originally Posted by lancefisher

That would do. It was indeed the X2 I was referring to.

That's an interesting concept, but probably 20 years behind the tiltrotor in terms of maturity.

[iGismo]

Originally Posted by Nav8tor

That's an interesting concept, but probably 20 years behind the tiltrotor in terms of maturity.

Just the swashplate linkages must be unusual since the 90 degree phase lead is in opposite directions. In addition to that I suspect that something special has to be done to decrease the AOA on the retreating blades as the forward speed increases. In order to eliminate the retreating blade stall, the loading of each of the two disks would have to be rather imbalanced, with only the sum of the two providing symmetrical lift.

[iGismo]

Originally Posted by Nav8tor

I'm having difficulty visualizing the concept. How would putting the prop on the bottom make such a high speed possible?

I think Dave is picturing a ship where the whole fuselage including cockpit pitches from vertical to forward when switching from VTOL mode to highspeed forward flight.

[Dave Krall CFII SEL SES]

Originally Posted by lancefisher

I think Dave is picturing a ship where the whole fuselage including cockpit pitches from vertical to forward when switching from VTOL mode to highspeed forward flight.

You are correct. The swiveling of the whole cockpit inside the airframe would be just to permit best visibility during VTOL and in cruise. It was really the only shortcoming of the high speed and functional "POGO".

BTW:
Carter Copter didn't appear blow another Corvette engine, but recently rolled, pitched, & crashed in the trees at 70 mph after claiming and supposedly reaching the "mythical" Mu barrier at the non-too-impressive speed of 170 mph, probably achieved mainly by the massive thrust of the rear prop/engine combo.

I'm not an aerodynamic engineer, but I read something about it once and again, so good enough, and continue to maintain that the dragging along of the verticle prop in horizontal flight is an exceedingly poor approach when compared to either tilt rotor, tilt fuselage, or folding verticle blade/rear prop approaches when the high end forward speeds such as 3-500 knots are sought.