Faceting for stealth shown in open literature before F-117 unveiling

[overscan (PaulMM)]

Found in an AIAA paper on advanced engine technology from 1981.... looks like faceting to me?

 

[overscan (PaulMM)]

The first mention I recall of faceting was in Bill Sweetman's "Stealth Aircraft" around 1986/87 ish?

 

[Antonio]

Very interesting, thanks Paul.

I have some conceptual drawings from Bill Gunston from the same decade and he always show smooth designs with a "Northrop look". I didn't discovered faceting until I saw the first F-117 pic.

 

[Orionblamblam]

Yes, that's facetting ("mulptiple coplanar surfaces"). What's the paper?

 

[flateric]

AIAA-81-1506
Combat Survivability with
Advanced Aircraft Propulsion
Development

L.W. Throndson, Naval
Weapons Center,
China Lake, CA

Thanks for great finding, Overscan!

 

[overscan (PaulMM)]

I wonder if that sketch inspired Italeri's MiG-37 Ferret-E?

 

[flateric]

Remembering these well-known faceted pieces of wood that were presented to firsts F-117 pilots as memorabilia to mask all the cross reference between faceting LO technology and actual airfrimes, i wonder how Mr. Throndson was faceted after this obvious leak.

 

[flateric]

I bet I've seen recently Varieze-based RPV(?) with significant faceting of forward fuselage from the mid-80s, but still can't find image in my 2Tb of stuff...

 

[LowObservable]

Wow... that paper being on the loose must have given people nasty moments, although fortunately most of the facets are pointed in exactly the wrong direction.

The Long-Eze thing was the Scaled Composites Model 144 aka California Microwave CM-44, IIRC...

 

[flateric]

-

 

[AeroFranz]

Isn't the Long EZ made out of fiberglass and foam core (at least the original ones)? you should be able to see right through it with radar and get reflections off the internal reflective components (me thinks). Furthermore, I think the prop and other non-aligned parts of the airframe would swamp whatever benefit you could get with faceting just the nose.
So what's with the curious shape of the nose? was it something related to the purpose of the testbed? ???

 

[archipeppe]

I wonder if that sketch inspired Italeri's MiG-37 Ferret-E?

I asked to myself the same thing....

It really looks like the "Ferret-E" model (I received it as gift for my birthday, long long ago back in the glamorous 80s).

 

[RayBee27]

Isn't the Long EZ made out of fiberglass and foam core (at least the original ones)? you should be able to see right through it with radar and get reflections off the internal reflective components (me thinks). Furthermore, I think the prop and other non-aligned parts of the airframe would swamp whatever benefit you could get with faceting just the nose.
So what's with the curious shape of the nose? was it something related to the purpose of the testbed? ???

Could it be a window for a camera?

 

[Stargazer2006]

The California Microwave CM-30 led to the CM-44 (Scaled Composites 144) and finally the CM-46, which can be seen here:
http://www.secretprojects.co.uk/forum/index.php/topic,11288.0

 

[firepilot]

There was a book, I believe called "Stealth" that had a blue cover on it that was published in the 86ish timeframe I believe. While the other books had mainly stuck to the curved surfaces idea, this one had stated that it believed the (F-117A) was faceted, and not curved.

 

[Ian33]

I always wondered what the reaction was when the faceted Lampryidae airframe was seen in MBB hangers during prototyping.

 

[overscan (PaulMM)]

There was a book, I believe called "Stealth" that had a blue cover on it that was published in the 86ish timeframe I believe. While the other books had mainly stuck to the curved surfaces idea, this one had stated that it believed the (F-117A) was faceted, and not curved.

Yes, this was by Bill Sweetman and was the first time I read about faceting, as I posted earlier in the topic. The picture I posted was however from an unclassified article from 5 years previous to that.

Interestingly L.W. Throndson was previously at Rockwell - this faceted concept having some conceptual commonality to the Rockwell "Surprise Fighter" design.

http://www.secretprojects.co.uk/forum/index.php/topic,4475.0/highlight,rockwell+surprise.html

 

[firepilot]

Thanks, I could not remember who wrote it, and it had been a long time since I have seen a copy of it.

 

[overscan (PaulMM)]

Lampyridae type faceted stealth configuration was shown at a 1986 AGARD conference on fighter design.


Source:


http://www.dtic.mil/dtic/tr/fulltext/u2/a192214.pdf

 

[chuck4]

According to the designer of lampyridae, any physicist during the past 100 years could have worked the basic principles of facet stealth. The trick is to apply it to something that could fly.

 

[famvburg]

ISTR hearing about a book by a Soviet designer, maybe from the '60s, regarding stealth and I think it discussed faceting. also, not that I have ever heard it referred to faceted surfaces, but the fictional Firefox from the movie has a faceted nose section, and the movie was made in '81 and released in '82. I guess you could also say the fictional Blue Thunder helo from the movie used faceted surfaces and it was released in '83.

 

[Sundog]

ISTR hearing about a book by a Soviet designer, maybe from the '60s, regarding stealth and I think it discussed faceting. also, not that I have ever heard it referred to faceted surfaces, but the fictional Firefox from the movie has a faceted nose section, and the movie was made in '81 and released in '82. I guess you could also say the fictional Blue Thunder helo from the movie used faceted surfaces and it was released in '83.

With regards to Firefox, I believe the design of the movie aircraft was aided by engineers from Northrop explaining some features such an aircraft might have, IIRC. As for Blue Thunder, I don't think the panels had anything to do with stealth and everything to do with making a relatively low cost movie helo.

 

[famvburg]

According to at least one magazine article, input from Lockheed engineers.

 

[AeroFranz]

faceting on attack helos is to reduce glint - at least that was the reason given for the AH-1 switch from curved to flat in later models.

 

[famvburg]

Also, probably, since it was using technology related to the Apache and the Apache had flat surfaces.

 

[flateric]

CRACKS IN THE BLACK DIKE -SECRECY, THE MEDIA, AND THE F-117A
JIM CUNNINGHAM
http://www.airpower.maxwell.af.mil/airchronicles/apj/apj91/fal91/cunn.htm

 

[shedofdread]

Sorry - I can't cite a reference for this but I seem to recall reading somewhere that the Germans faceted the tops of periscopes in an attempt to defeat Allied radar. Anyone else remember this?