Boeing Looks To First Silent Eagle Flight

Avation Week and Space Technology ^ | 1/16/2010 | Amy Butler

[ErnstStavroBlofeld]

With radar-cross-section (RCS) trials for Boeing’s Silent Eagle semi-stealthy F-15 prototype complete, company officials are now focusing on South Korea as a possible first customer.

The RCS testing took place during a two-week period last August and September, although Boeing has only just acknowledged it because of proprietary issues, says Mark Bass, vice president of F-15 programs.

The company is eyeing South Korea’s forthcoming F-X3 competition for 60 fighters as the first sales opportunity for the Silent Eagle. The South Korean parliament’s recent hesitancy about investing in all-stealth aircraft “validates our approach” with the aircraft, says Bass. The company is considering potential international co-development partners for a Silent Eagle conformal fuel tank, although no announcements have been made.

Boeing is developing the variant for international customers that already operate F-15s and are seeking additional aircraft. The system is a possible alternative for nations interested in the Lockheed Martin F-35 Joint Strike Fighter. The Silent Eagle is not as stealthy as the JSF, but it could provide flexibility for countries trying to stretch their defense dollars.

In the early days of an air campaign, the Silent Eagle can be outfitted with weapon bays suitable for carrying air-to-air and air-to-ground weapons that would be tucked inside conformal fuel tanks, thus reducing the aircraft’s front-quadrant RCS. The aircraft could then be reconfigured in hours to handle the F-15’s characteristic heavy load of weapons once early threats are removed and sustainment operations begin.

The RCS tests on F-15E1, an Air Force test asset leased to Boeing, took place at the company’s anechoic chamber in St. Louis. Various coatings were evaluated and a final candidate has been selected and applied to the appropriate portions of the airframe. Testing produced the desired results, he said. Bass declined to provide details on the coating or the precise

[Tallguy]

I wonder how stable the Horten’s would have been in flight? Northrop did a lot of work with flying wings & had a heckuva time solving those problems in an era long before fly-by-wire.

[mad_as_he$$]

I have heard that it was a bear but the size made it controllable.

I have seen a series about the B-2 where the guys from Northrup got special permission to go see Jack basically on his death bed to tell him the “wing could fly”. As i remember the prototypes (old ones) were lost due to uncontrollable yaw issues.

[Oztrich Boy]

As i remember the prototypes (old ones) were lost due to uncontrollable yaw issues

Although there was yaw, the losses were unrelated to that.

Both the original prop powered XB-35s survived to be scrapped.

Of the three YB-35s converted to YB-49s, one suffered structural failure in flight, and one was lost in taxi trials, the last being scrapped.

[mad_as_he$$]

Thanks. Could not remember exactly. I saw an interview with one of the test pilots who flew one across country for some fly by of DC (I think) so he made it anyway. One comment he made was that they would yaw back and forth the whole time in the air.

[Screaming_Gerbil]

Horten Ho 229

"Hitler's Stealth Fighter" Re-created

[Rebelbase]

“And yet the F-22 line has been canceled. The Eagle is 40 years old from the drawing board.”

Sheesh. How else are the Chicoms supposed to acheive parity with us?

[GonzoGOP]

Northrop did a lot of work with flying wings & had a heckuva time solving those problems in an era long before fly-by-wire.

Remember the Horton was a fighter so a little bit of yaw wasn't as big of an issue. When bombing with iron bombs from 30,000 feet a half a degree of oscillation (and that is about all it was) can make the run useless. In a fighter pulling G's in a turn it is barely noticeable compared to the other factors.

[Tallguy]

I take your point. I wouldn’t think that the Horten was designed for a turning fight, however. More along the lines of a high-speed, blow-thru attack.

I also wonder if low-radar observability was really what the designer was after or weather it was a by-product associated with an attempt to minimize drag while optimizing speed.

[GonzoGOP]

I take your point. I wouldn’t think that the Horten was designed for a turning fight, however. More along the lines of a high-speed, blow-thru attack.

A flying wing naturally has very low wing loading. And the center of mass and center of gravity are very close. The problem is getting them to go straight line, they turn turn beautifully. Their are rumors that the B-2 can out turn some fighters. Not that anyone would risk an aircraft that expensive in a dogfight. Also a flying wing distributes the G-forces more evenly than a traditional tube and wing structure. It's harder to pull the wings off when the whole aircraft is the wing.

I also wonder if low-radar observability was really what the designer was after or weather it was a by-product associated with an attempt to minimize drag while optimizing speed. It was an accident caused by the inherent stealth of a flying wing design and the fact that due to metal shortages it was made largely out of plywood. Rivet lines are great radar reflectors and the wood actually absorbs radar waves.

[tradergem]

Thanks for the cool pics.

I've read a lot about Jack Northrop's work on his flying

wings and I think the USAF could have had an effective

aluminum skined version by the late 1950’s if it wasn't so

politically unacceptable to the top brass in the USAF at

the time.

There were two major complaints about the Northrop YB-49’s

that the brass used as an excuse to stop development of the

planes.

1) The bombadiers found it almost impossilbe to hold a

steady course on target because of the hyper sensitivity of

the rudders under manual control which caused excessive

yawing back and forth left to right.

2) The bombays had been designed for conventional bombs of

the day and were not big enough for the new nuclear bombs.

Both of these problems could have been overcome by

inclusion of a autopilot to dampen the excess yaw and

enlarging the bombays.

But the real problem was that most of the top brass just

didn't like the way the flying wing looked. It didn't look

like what they thought a bomber should look like.

Instead they went with the Convair B-36 which in my opinion

was not a very successful design.

[Oztrich Boy]

But the real problem was that most of the top brass just didn't like the way the flying wing looked. It didn't look like what they thought a bomber should look like. Instead they went with the Convair B-36 which in my opinion was not a very successful design.

Yes the B-35 would have matched the performance of the B-36 with a 30% smaller aircraft on the original specification , which was carrying 10,000 lbs to Nazi Germany from Continental US.

But that job was never needed, and what was needed post war was carrying short fat special stores to Russia.

Those would never fit in the B-35, while the B-36 , designed to carry two 42,000 conventional bombs, could carry short fat fission bombs designed for the B-29/50, and even long fat superbombs that were thought needed in c.1950 with ease (It was the only plane that the Mks 14,17,24 would fit)

enlarging the bombays.

Unfortunately they were in the wings, and it was going to be impossible to make them any deeper, so the suggestion was to carry the bomb semi-externaly, which would have severely shorted the range, which had been already taken a hit by turning it into the jet B-49.

Even so, the only bomb that would sort of fit was the Mk15, a puny 2 megatons, when the B-47 could carry the 10 Megaton Mk21/36.

It would be the late 50s before the USAF had a bomb that would fit inside the B-49, and by that time the B-58, which had three times the speed, 50% more altitude, and the same range, was available.

The Northrop Flying Wing was always the wrong plane for the time (except that of the alternate history universe of Newton Leroy Gincrich's novel 1945).

[myknowledge]

F-15SE Silent Eagle - the best machine from St. Louis, MO.