US Air Force shares new images of B-21 Raider nuclear stealth bomber

originally posted by: YouSir

originally posted by: Zaphod58
a reply to: YouSir

You’re also assuming the coating is applied. If it’s a ground, or static test airframe it won’t have a coating, while being a completed aircraft. If it’s a flight test aircraft it isn’t necessary to have its coating applied until some time before it actually flies. Once the coating is applied most of that will be covered.

Ummm...look...you already covered that in your previous post...

Was it really necessary to reiterate it...?

This isn't a points game...it's a discussion...where you might know that it's a never to be flown prototype...a layman might not...I merely commented on its unfinished appearance...which you clarified...

Twice...

My second point...not addressed to you...was about aerodynamics and why riveted fighter and other planes moved from exposed head rivets to the flush mount ones currently in use...Again...thanks to Howard Hughs...

Is there anything else you'd care to add...?

YouSir

A slight addition to Zaphod's answer about parasite drag: The relative importance of parasite drag increases fairly rapidly with the speed of the aircraft. In the early days of aviation aircraft didn't fly fast enough that it was that much of a factor. Howard Hughes' H-1 racer was designed to fly at somewhere in the vicinity of Mach 0.5, and he was looking for every last MPH.

To this day, many aluminum helicopters don't fly fast enough to justify flush rivets.

With composite construction however, (glass, Kevlar, Carbon Fiber) you get a smooth skin at no extra charge.

I would imagine it appears very triangle like from below. At night... with 3 lights on.

And what is that bird in the image near the nose landing gear? Hawk, falcon, eagle all heave this fan like tail, a swallow has a double tail... what bird looks like that silhouette?

Like a hybrid logo, something between a bird and a bomber.

Rivets usually get "Aerosmoothing" done during assembly. All lap and butt joints get sealers that fill in things as well. Reduces drag but adds weight, all part of the design engineering. Very impressive looking craft.

I did that kind of work at Boeing years ago. Am still working as an aerospace painter.

a reply to: Mahogany

It’s a nod to the old Northrop Flight Test logo.

imgur.com...

That thing looks cool as ice either way. I bet that coating has something to do with it's invisibility to radar. Just an uneducated guess.

Something odd stands out to me. With all the triangular shaped "UAP's" being reported (having seen something triangular in the sky myself) does anyone think it's a coincidence that the last two bombers have been that triangular shape? Put a few lights on the bottom, and make it hover, and that looks like a UFO to me. Almost seems like they have gotten some help with their technology and aeronautics, or the weird triangle flying objects are their's as well.

Really cool aircraft though. Great post ⭐.

a reply to: AOx6179

Flying wings have an inherently reduced RCS. So you’re basically starting to build a stealth bomber with an already reduced RCS from the start. Then it’s just a matter of adding stealthy features like buried engines and exhaust, and RAM coating. One of the things that makes stealth fighters more detectable is the fact that they have vertical tails. There’s an air current that comes off the top of the fin that creates an eddy that can be detected somewhat by low frequency radar. A flying wing with no vertical fin doesn’t have that problem.

originally posted by: Zaphod58
a reply to: AOx6179

Flying wings have an inherently reduced RCS. So you’re basically starting to build a stealth bomber with an already reduced RCS from the start. Then it’s just a matter of adding stealthy features like buried engines and exhaust, and RAM coating. One of the things that makes stealth fighters more detectable is the fact that they have vertical tails. There’s an air current that comes off the top of the fin that creates an eddy that can be detected somewhat by low frequency radar. A flying wing with no vertical fin doesn’t have that problem.

Makes sense.

That's one reason why the SR-71 became obsolete then, since it had the two wings on the tail?
I just thought it stood out being triangular, and all these UAP sightings of triangular shaped objects in the sky. I wandered in thought a bit on this one.

I am surprised with the white as well.

a reply to: AOx6179

No, the SR-71 just flat outran everything thrown at it. It just got too expensive to maintain as it got older. It required special fuel, and triethylborane to ignite the fuel because the flashpoint was so high.

originally posted by: Zaphod58
a reply to: AOx6179

No, the SR-71 just flat outran everything thrown at it. It just got too expensive to maintain as it got older. It required special fuel, and triethylborane to ignite the fuel because the flashpoint was so high.

That one was my favorite. Sounds like it was just too bada** to keep in the skies.

Thanks for the input. I did not know that.

a reply to: AOx6179

They would have to use the TEB to ignite the afterburners in flight, so every time they'd have to light them, they'd have to use TEB. They had enough for 16 injections of it in flight.

a reply to: AOx6179

I was thinking the same thing.

I've been obsessed with the Triangles since I first heard about sightings in the 80s and when they first debuted the Lockheed Bomber I was so jazzed.

This style always brings me back to the Mythical TR3B and Aurora and I would love to see one in person some day....but not on the receiving end of a payload!

That said...she sure is Purdy.

a reply to: GENERAL EYES

Neither are real though.

a reply to: Zaphod58

A girl can dream.

originally posted by: Zaphod58
a reply to: GENERAL EYES

Neither are real though.

She did say "mythical".

Least she didnt say Tr3b :-P

originally posted by: 1947boomer

originally posted by: YouSir

originally posted by: Zaphod58
a reply to: YouSir

You’re also assuming the coating is applied. If it’s a ground, or static test airframe it won’t have a coating, while being a completed aircraft. If it’s a flight test aircraft it isn’t necessary to have its coating applied until some time before it actually flies. Once the coating is applied most of that will be covered.

Ummm...look...you already covered that in your previous post...

Was it really necessary to reiterate it...?

This isn't a points game...it's a discussion...where you might know that it's a never to be flown prototype...a layman might not...I merely commented on its unfinished appearance...which you clarified...

Twice...

My second point...not addressed to you...was about aerodynamics and why riveted fighter and other planes moved from exposed head rivets to the flush mount ones currently in use...Again...thanks to Howard Hughs...

Is there anything else you'd care to add...?

YouSir

A slight addition to Zaphod's answer about parasite drag: The relative importance of parasite drag increases fairly rapidly with the speed of the aircraft. In the early days of aviation aircraft didn't fly fast enough that it was that much of a factor. Howard Hughes' H-1 racer was designed to fly at somewhere in the vicinity of Mach 0.5, and he was looking for every last MPH.

To this day, many aluminum helicopters don't fly fast enough to justify flush rivets.

With composite construction however, (glass, Kevlar, Carbon Fiber) you get a smooth skin at no extra charge.

Ummm...I know...I deal with the same issue of parasitic drag in the marine industry...My comments were from personal experience using composite materials in repair...layup and finish coatings...I naturally assumed the same issues might affect aircraft in the airstream as hulls in a hydrodynamic and hydraulic pressure setting...

Thank you for the clarification...



YouSir

a reply to: YouSir

When you say "composite materials", can you clarify which ones?

Thanks in advance

originally posted by: Oldcarpy2
a reply to: YouSir

When you say "composite materials", can you clarify which ones?

Thanks in advance

Ummm…a matrix of mat…woven roving…biaxial or cross woven cloth in either fiberglass…carbon fiber…or aramid fiber…over an initial layer of gel coat...(in composite boat construction)…either used separately or an admixture in a vacuum bagged epoxy impregnated environment…usually but not always in conjunction with a mold to form the shape of the structure…

The vacuum bag not only removes gases/voids from the resin/hardener…it also removes excess epoxy from the fibers so that a uniform and much stronger…lighter structure is achieved…

It all depends on what the purpose of use of the structure is designed for that determines the materials used…




YouSir

a reply to: YouSir

Thanks. So that makes you an expert on aircraft stealth tech?

I believe that Zaphod et al are probably a bit more knowledgeable about such things.

originally posted by: Oldcarpy2
a reply to: YouSir

Thanks. So that makes you an expert on aircraft stealth tech?

Ummm....How on earth did you extrapolate any claims of expertise in stealth craft tech...by making an observation on the obviously unfinished appearance of the B-21...?

I made an observation...Zaphod...provided clarification on why it has an unfinished appearance...because it's unfinished...

I do have experience using much the same techniques in composite construction used in aircraft...for much the same reasons...although in completely different environments...however the reasons for using composite materials in both settings remains the same...

Greater strength to weight...reduction of parasitic drag on the hull form...ability to withstand hydrodynamic and aerodynamic pressures while retaining structural integrity...

These principles are specific to multiple disciplines across multiple industries...and not inherently specific to only one.

If that's not good enough for you...then by all means...have a nice day...

I've tried to be congenial to you...I'll not make that mistake again...



YouSir