B-70A Valkyrie Status?

[MKSheppard 4]

So when do we get to burn through enemy defenses at Mach 3.0 at 85,000 feet?

 

BTW:

 

Actually, the RCS of an aircraft is not a single number. The RCS is different for each "look-angle" (i.e.. direction from the threat radar). When graphed in polar coordinates, RCS appears as shown in Fig. 8.14. This is actual data for the B-70 supersonic bomber. As can be seen, RCS varies widely from different directions, by almost four orders of magnitude for this design.

 

We use the expression "spikes" to describe directions from which the RCS of an aircraft is very high. These are typically perpendicular to the leading and trailing edges of the wing, perpendicular to the flat side of the aircraft unless it is properly shaped and treated, and directly off the nose and tail due to the inlets, nozzles, radome, and other features. For the B-70. huge spikes are evident to the sides perpendicular to the big flat sides of the nacelle. However, with a cruising speed of Mach 3.0 at almost 80,000 ft {24,300 m}, it would be difficult to intercept a B-70 that was already flying past. Unfortunately, there are also substantial spikes just off the nose, perpendicular to the leading edges of the canards, which have fairly low sweep. These spikes would have warned defenders that a B-70 was coming. As shown, treatment with RAM was under serious consideration for operational B-70s. This would have reduced the nose-on signature by several orders of magnitude.

[+Jarhead1 27]

In two weeks!!

[Lexx_Luthor 57]

Is that RCS reduction, or increase? 100sqm is big, 100,000sqm is an aircraft carrier. I don't know much about this subject so lala...

 

That plume in the back, big IR signature especially in the clear cold dry air near space. However, I've read that the B-70 didn't use afterburner for Mach 3 cruise, just to accelerate to that speed where the wave riding offers *less* drag than found at lower speeds, for this design. The uneeded power of the burners could however be used to maintain Mach 3 in the event of multiple engine failure. That's what I read, but from only one source, and I have not confirmed that anywhere, and I kinda need to.

[MKSheppard 4]

Is that RCS reduction, or increase? 100sqm is big, 100,000sqm is an aircraft carrier. I don't know much about this subject so lala...

 

That plume in the back, big IR signature especially in the clear cold dry air near space.

 

Reduction.

 

As for IR Signature. Not as big as you might think:

 

From a book on the B-70:

 

Of course, the airframe itself was a thermal target because of the frictional heat generated during Mach-3 flight. As part of it's research, North American developed a "finish system" (i.e., paint) that provided a low emittance at wavelengths used by soviet infrared detecting devices, while radiating most of the excess heat from the surface of the airframe in wavelengths not normally under surveillance. The finish used a low emittance basecoat with an organic topcoat that was transparent to energy in the 1 to 6 micron range. The top coating was strangely opaque and highly emissive at wavelengths between 6 and 15 microns. This finish was relatively invisible to infrared detecting equipment, while still allowing the skin to radiate excess heat overboard to maintain its structural integrity.144

 

The first attempt at defining the finish system brought new meaning to the term "gold plated," literally. A gold substrate was applied by electro-deposition to the aircraft; where the gold was applied directly over titanium, it would be baked on at high temperatures under infrared lamps. This was followed by an overlay of Kel-F No. 800 resin coating, and the entire aircraft was baked under infrared lamps. The coating demonstrated some reduction in emittance from the treated test panels, leading North American to believe they were on the right track, but obviously better coatings would need to be found. The gold substrate was only 0.00002-inch thick, but given that there was 17,000 square feet of surface area on the B-70, it still would take 31.7 pounds of the precious metal to cover the entire aircraft. Even at the official $32 per troy ounce price in effect at the time, this equaled $12,173 per aircraft, per treatment. An additional 15 pounds of nickel plating was used in areas that could not be covered with gold, and 187 pounds of Kel-F No. 800 topcoat were used.

[Lexx_Luthor 57]

Very interesting, thanks. Any info on afterburner usage during cruise?

 

As for the radar, how is it reduction instead of increase? 100sqm is big, 100,000sqm is an aircraft carrier, or that's my thinking anyway.

[Lexx_Luthor 57]

This is *really* neat stuff. What book is this, and is it still available? There seems to be a footnote numbered 144. Does it explain how this works?

 

Book::

This finish was relatively invisible to infrared detecting equipment, while still allowing the skin to radiate excess heat overboard to maintain its structural integrity.144

[MKSheppard 4]

Book is "Valkyrie: North American's Mach 3 Superbomber" and yes it's still available