Register here

Recent Posts

Pages: [1] 2 3 ... 10
Aerospace / Re: NPL Research Biplane Design
« Last post by Schneiderman on Yesterday at 11:20:25 pm »
I remember, many years ago, there was an article on Airspeed projects in 'Aeroplane Monthly',

December 1981
The Bar / German MK 101Z mid-air refuelling system?
« Last post by Pioneer on Yesterday at 09:33:13 pm »
G’day gents

Currently flicking through.Luftwaffe over America: The secret plans to bomb the United States in WWII, by Manfred Griehl.

In it, he States that the Luftwaffe had a mid-air refuelling system called the MK 101Z device. Does anyone have any details of this MK 101Z?
In the book, it states that the Luftwaffe tested the mid-air refuelling concept between a Junkers Ju 90 and a Ju 290 (if my memory serves me right)
Although the book alludes to the Luftwaffe favouring a Heinkel He 177 to He 177 concept.

Thank’s in advance!

Aerospace / Re: Chengdu J-20 news, pictures, analysis Part III
« Last post by Triton on Yesterday at 06:00:55 pm »
September 17, 2017

High speed taxiing of WS-10B powered J-20 2021, maiden flight in a few days via fyjs.

Aerospace / Re: Sikorsky S-97 Raider
« Last post by Triton on Yesterday at 05:20:03 pm »
"Lockheed Martin Reaffirms Support For Sikorsky’s Raider"
Second prototype will be completed to fulfill goals of high-speed helicopter program
Sep 14, 2017 James Drew and Graham Warwick | Aviation Week & Space Technology



Sikorsky was tantalizingly close to achieving its goal of exceeding 220 kt. with the S-97 Raider coaxial-rotor helicopter when the prototype made a hard landing on Aug. 2, after experiencing flight control problems. But Lockheed Martin, which acquired Sikorsky in 2015 when the industry-funded Raider program was well underway, has been quick to reiterate its commitment to the high-speed light tactical helicopter.

The incident at Sikorsky’s development flight center in West Palm Beach, Florida, came as the 6,000-lb. Raider was taxiing out to begin its 15th test flight, with the target of achieving 180 kt.—its highest speed yet. The goal of exceeding 220 kt. was planned for the next flight, its 16th. Achieving that objective will now have to wait until after the second prototype is completed and flown in 2018.

The fly-by-wire (FBW) Raider was taxiing to its takeoff position when the mishap occurred. The digital flight control system unexpectedly transitioned from simple ground mode to augmented flight mode before the aircraft became airborne. The crew lifted into a hover but, unable to stabilize the helicopter, quickly put it back on the ground, the Raider coming down heavily, upright and level on the runway. The two company test pilots powered down the engine and shut off the electrics before egressing. The Raider suffered substantial damage, but they escaped with minor injuries— the impact-absorbing landing gear, composite airframe and crew seats working as designed.

Investigation is ongoing with the National Transportation Safety Board (NTSB), but Sikorsky says its other fly-by-wire  helicopters—the CH-53K and CH-148 Cyclone—are not affected, as implementation of the Raider’s triplex-redundant control system is different. But any lessons learned from the investigation are being shared with the Sikorsky/Boeing team developing the SB-1 Defiant Joint Multi-Role demonstrator. Expected to fly by mid-2018, the 30,000-lb. SB-1 shares the same coaxial-rotor/pusher-propeller X2 configuration and a similar FBW control system.

The NTSB has issued only a brief preliminary report, but the suspected cause is a flight-control software issue relating to the “complex interaction between the ground, the landing gear, the flight control system and the pilot,” says Chris Van Buiten, vice president of Sikorsky Innovations. The failure has been reproduced in the S-97 flight simulator, and software changes are being made “to ensure it never happens again.”

Damage to the first prototype is a setback for an industry effort that has slowed significantly since its launch in 2010 as a $200 million follow-on to the Sikorsky-funded X2 Technology Demonstrator, which reached a speed of 262 kt. that year. The Raider first flew in May 2015 with the goal of achieving its key performance objectives by the middle of 2016. But changing customer plans, technical challenges and Sikorsky’s integration into Lockheed all slowed the pace.

The mishap was not related to the coaxial rigid-rotor X2 configuration, says Van Buiten, and Lockheed’s leadership has committed to return Raider to flight once the cause is fully established. Aircraft 1 will continue to support the investigation, so the second prototype, assembly of which had been halted, will be completed and flown in 2018. Changes made to the first prototype as a result of 20 hr. of flight tests and 100 hr. of ground runs will be incorporated into Aircraft 2 before it flies. 

After shakedown flights, the goal is to pick up where Aircraft 1 left off and continue expanding the flight envelope beyond 150 kt., out to the maximum speed goal. But more than that, Sikorsky is looking at arming the second Raider for mission demos. Once the S-97 finally achieves its 220-kt. target, the company aims to demonstrate complex maneuvers, including 3g turns, hovering nose-up and nose-down using the prop, as well as rapid level-attitude acceleration and deceleration.

Sikorsky will also install a weapons suite and other mission systems now being matured in the Raider systems integration laboratory. The weapons will include podded machine guns, Lockheed’s next-generation Hellfire—the Joint Air-to-Ground Missile—and BAE Systems’ Advanced Precision Kill Weapon System laser-guided rocket.

When Raider was launched with support from more than 30 suppliers, Sikorsky had its sights set firmly on the U.S. Army’s Advanced Aerial Scout (AAS) requirement to replace the Bell OH-58D Kiowa Warrior. But AAS was shelved in 2013, and the OH-58Ds have now retired, replaced with reroled Boeing AH-64E Apaches. The Army’s priority has shifted to the Future Vertical Lift (FVL) Medium program to replace the workhorse Sikorsky UH-60 Black Hawk—for which Sikorsky Boeing’s SB-1 is competing with Bell’s V-280 Valor tiltrotor.

Lockheed’s restated, post-crash commitment to Sikorsky’s Raider reflects the high-speed helicopter’s continued value, both in reducing risk for the SB-1 and in keeping options alive for a future FVL Light program to develop a true replacement for the OH-58D armed scout,  as well as the Army’s special-operations Boeing MH-6 Little Bird. “We remain bullish about the program,” says Van Buiten.

Aerospace / Re: JMR (Joint Multi-Role) & FVL (Future Vertical Lift) Programs
« Last post by Triton on Yesterday at 05:00:48 pm »
"V-280, SB>1 Are Vehicles to Lessons Learned"
by Dan Parsons, S.L. Fuller | September 13, 2017


As the industry readies its experimental vertical-lift aircraft for U.S. Army evaluation, aviation officials have made clear they do not consider the Future Vertical Lift (FVL) Joint Multi-Role Technology Demonstrators (JMR-TD) to be prototypes of future helicopters. “JMR-TD are not prototypes. They are an experiment of technologies,” said Maj. Gen. William Gayler, chief of the Army Aviation Center of Excellence (AACE) Gayler, at a recent Army aviation forum hosted by the Association of the U.S. Army. “It’s going to inform what the final requirements will be. It’s really important … it’s the relationship of the attributes that are important to us.

“Industry is certainly trying to provide an option, but what industry has right now is not a prototype,” Gayler told Defense Daily, an R&WI sister publication, at the event. “It is going to be very informative to the final solution. I think we have to have that. We’ve got to have industry leaning forward. If industry listens to concepts and how we will fight and what combination of attributes will be important to us, it will only help them in the future.”

Gayler also said that FVL will not necessarily consist of one rotorcraft design scaled up and/or down to perform different missions, because certain airframe designs may not scale in the same direction.

“It is absolutely possible for us to envision different aircraft,” Gayler said. “We’re looking for the capability and the relationship of those attributes that provides the best capability in its class. I can envision the introduction of capability of several different variants that look distinctly different.”

Whether the Army would be able to martial the funding necessary to pursue two separate rotorcraft development and acquisition programs at once remains to be seen, Gayler said.

Affordability and efficiency has been a theme in the Army’s pursuit of future aircraft. If the service is going to replace its entire fleet in a timely fashion, it will need to be calculated.

“If your fleet is 2,135-strong, it is going to take continuous production, at almost max production rates, 40 years to turn that fleet over,” said Brig. Gen. Thomas Todd, who moderated a panel on science and technology for future aviation operations. “So we have to ask ourselves, ‘Do we really want to continue to put ourselves in that box?’ In order to succeed, we would need to be strategic as we move forward in developing capability.”

That, he continued, could entail buying fewer aircraft. If so, the aircraft would need to be all the more efficient.

The two designs officially participating in the technology demonstrator are Bell Helicopter’s V-280 and the SB>1 Defiant, from a Sikorsky-Boeing team. Bell’s advanced tiltrotor is built on experience manufacturing the V-22 Osprey, and the Defiant’s coaxial-rotor technology has been developed by Sikorsky through its X-2 and S-97 experimental aircraft. All three manufacturers had seats on Todd’s panel. Bell’s VP of Advanced Tiltrotor Systems, Keith Flail, noted that the company has learned lessons about affordability from participating in the FVL program. Bell completed construction of its V-280 last week.

“Those kinds of things — really looking at affordability and what affordability means to the department and to the Army — is something we have really been able to wrap into this,” he said of the V-280’s development process. “I don’t think a lot of folks at the beginning of JMR really thought that we would get that kind of learning out of this. We can get a lot of learning about technology, but there’s learning that is applying across the entire lifecycle and across the entire acquisition process.”

Sikorsky’s VP of innovations, Chris Van Buiten, said that its FVL offering is set to make its first flight next year. One focus for Van Buiten and Sikorsky Innovations is autonomy. He said the technology could have applications for the Army, however far down the road that might be.

“We want to put autonomy in the airplane to augment the group. Some call it ‘optimally piloted,’” Van Buiten said. “The crew is going to be there for most of the mission, but put a degree of autonomy to enable flight in degraded visual environments, high workload environments, enable manned/unmanned teaming by unloading the crew and letting the autonomy system take on a lot of the mission.”

Another focus for the company is intelligence. Van Buiten said Sikorsky is actively downloading gigs of data from its commercial fleet every night, and it’s then processed by “an increasingly capable supercomputer cluster.” This has led to increased availability and a decrease in maintenance.

“It’s very intense; it’s a whole new field,” he said of the technology. “And increasingly you’ll see it start to converge with the autonomy. All are enablers for Future Vertical Lift.”

The company has its Sikorsky Autonomy Research Aircraft (SARA), an autonomous S-76, on a certification path. Van Buiten also mentioned it is building autonomous capabilities onto a Black Hawk demonstrator, which he said the industry and public would “see a lot more of next year.”

Sikorsky’s S-97 Raider, a smaller version of the SB>1 Defiant it has pitched for the JMR-TD program, has been flying for more than a year. One of the two existing prototypes suffered a hard landing in August, but the company said the mishap will not hinder the progress of the program, which is meant to validate the coaxial-rotor design. The S-97 suffered “substantial damage,” according to a National Transportation Safety Board preliminary report on the Aug. 2 accident in Jupiter, Fla. The preliminary report was published Aug. 11 and shows that both pilots on board suffered minor injuries when the aircraft went down on a clear day while hovering. Sikorsky plans to get its second S-97 airborne in the near future, and resume flight testing.

Brig. Gen. Frank Tate, director of Army Aviation for the Army Deputy Chief of Staff, G-3/5/7, is closely watching both teams’ flight testing and is eager to continue working with industry to achieve FVL. However, he said he is focused on the capability certain technologies offer rather than the design of any specific aircraft.

“We continue to look forward and work with industry to do relatively low-cost tech demonstrators, then demonstrate the validity of leap-ahead technologies that take the physics of vertical lift to a whole other level that we need to get to, to get after the capability gaps we have discussed,” Tate said.

“Then you close in on your actual requirements and put that out to industry, now knowing what is … achievable and get to more rapidly an actual product on the street,” he added. “We are focused on how we do our requirements process so we can do that much faster and do it in a way that is smart, that will get us what we want, that is not so constraining that you possibly throw away things that are achievable more quickly and are still a giant leap ahead.”
Aerospace / Re: KFX Korean Indigenous Fighter programme
« Last post by Ogami musashi on Yesterday at 03:04:01 pm »
Hello DWG,

If i'm not mistaken, you say that the actual code doesn't contain the control allocation equation that you can find in Durham, Nixon and other sources. This what i don't really understand. How would you code the control allocation then (how much you need to move a control surface to reach the desired performance)?

As for the languages, i had in mind C,C++ and fortran that are pretty well adapted (and efficient) to matrix algebra. i said "most" because i guessed that you probably coded in ada and i don't know a single thing on that language :)
Aerospace / Re: NPL Research Biplane Design
« Last post by hesham on Yesterday at 02:50:03 pm »
Great Info my dear Robunos.
Aerospace / Re: NPL Research Biplane Design
« Last post by robunos on Yesterday at 02:33:49 pm »
I remember, many years ago, there was an article on Airspeed projects in 'Aeroplane Monthly', and the shape stuck in my mind. I still have that article, somewhere . . . it was easier to pull the Putnam.
Drifting OT, the monoplane AS.27 is so American looking, if it wasn't for the 'Airspeed' fin and rudder, one would think it was a Monocoupe, a Luscombe, or even a Cessna . . .

The Bar / R.I.P. Stanislav Yevgrafovich Petrov
« Last post by thefrecklepuny on Yesterday at 01:51:39 pm »
Yep, the man who is credited for averting nuclear war in 1983 has passed away.

As most of us know, Soviet computer systems reported half a dozen US Minuteman warheads heading for the USSR. For a good few minutes, Petrov was in placed a perilous position, report this as a US pre-emptive strike or not. Thankfully he did the latter and used his better judgement as he rightly surmised the Americans would not attack in such low numbers. The false alarm was apparently set off when satellites mistook the sun’s reflection off the tops of clouds for a US missile launch.

Little wonder things were jittery due to a Korean Airlines 747 being shot down over Soviet territory less than a month earlier and 'Able Archer '83' being conducted just a month later.

Petrov apparantly passed away on 19 May 2017 but his death was not reported at the time. He was 77.

Apologies if news of this posted already.

Aerospace / Re: NPL Research Biplane Design
« Last post by Schneiderman on Yesterday at 01:29:45 pm »
And here is the patent I knew had to be out there, GB450676, Henry Braid Irving 1934.
Pages: [1] 2 3 ... 10