Mach 2, 60,000 foot B-1R

[Paul F Austin]

From this week's AvWeek. Boeing responded to an Air Force RFI against a
requirement for improved bombers by suggesting re-engining the B-1 fleet
with F-119 engines with the following characteristics: Mach 2 cruise, 3000
mile radius, 60,000 foot ceiling (with a couple of hours loiter).

Is this plausible? From others in this group, I though the B-1 was marginal
above 30,000 feet.

[Scott Ferrin]

On Tue, 1 Jun 2004 19:50:12 -0400, "Paul F Austin"
> wrote:

>From this week's AvWeek. Boeing responded to an Air Force RFI against a
>requirement for improved bombers by suggesting re-engining the B-1 fleet
>with F-119 engines with the following characteristics: Mach 2 cruise, 3000
>mile radius, 60,000 foot ceiling (with a couple of hours loiter).
>
>Is this plausible? From others in this group, I though the B-1 was marginal
>above 30,000 feet.


1. Different engines.

2. I think the Mach 2 figure was dash speed. I don't recall it
saying it could cruise that fast. One thing I was wondering is the
B-1 lost Mach 2 capability when they changed the inlets. Are they
going to change them again?

3. The B-1A could do Mach 2.2 at 60,000ft so the basic airframe is
capable of it. Comes down to the engines, intakes, weight. The
article raised more questions than it answered.


I also thought the aritcle talking about the F-22 chasing down Mach
0.6 cruise missiles a particularly desperate move. If they want to
sell the F-22s capabilities why don't they mention how it will enable
the US to maintain air supremacy over any battlefield anywhere? For
one thing if you're against an opponent you'd use F-22's against
they're not likley to be using Mach 0.6 cruise missiles. And if the
missiles are supersonic or the ballistic variety their scenario pretty
much falls apart. Why don't they mention the deterent value a
squadron or two of F-22's deployed to Taiwan in a crises would be? Oh
wait, that's not PC. The areas where the F-22 will really shine are
those where the F-15 might have a difficult time and that's against a
country with relatively large numbers of modern, high performance
aircraft. And that means China, India and East Asia in general. For
those who scoff at the idea of China ever being a threat you need to
take off the blinders. The whole China / Taiwan thing is going to
come to a head eventually and if we plan to stick to our word (fat
chance these days) then we had better be prepared.

[breyfogle]

The F119 engines make sufficient thrust to allow high altitude supersonic
cruise at a Mach somewhat less than Mach 2 while not requiring any
significant change to the current fixed inlets. The tradeoff is a
significant reduction in range.
<Scott Ferrin> wrote in message
...
> On Tue, 1 Jun 2004 19:50:12 -0400, "Paul F Austin"
> > wrote:
>
> >From this week's AvWeek. Boeing responded to an Air Force RFI against a
> >requirement for improved bombers by suggesting re-engining the B-1 fleet
> >with F-119 engines with the following characteristics: Mach 2 cruise,
3000
> >mile radius, 60,000 foot ceiling (with a couple of hours loiter).
> >
> >Is this plausible? From others in this group, I though the B-1 was
marginal
> >above 30,000 feet.
>
>
> 1. Different engines.
>
> 2. I think the Mach 2 figure was dash speed. I don't recall it
> saying it could cruise that fast. One thing I was wondering is the
> B-1 lost Mach 2 capability when they changed the inlets. Are they
> going to change them again?
>
> 3. The B-1A could do Mach 2.2 at 60,000ft so the basic airframe is
> capable of it. Comes down to the engines, intakes, weight. The
> article raised more questions than it answered.
>
>
> I also thought the aritcle talking about the F-22 chasing down Mach
> 0.6 cruise missiles a particularly desperate move. If they want to
> sell the F-22s capabilities why don't they mention how it will enable
> the US to maintain air supremacy over any battlefield anywhere? For
> one thing if you're against an opponent you'd use F-22's against
> they're not likley to be using Mach 0.6 cruise missiles. And if the
> missiles are supersonic or the ballistic variety their scenario pretty
> much falls apart. Why don't they mention the deterent value a
> squadron or two of F-22's deployed to Taiwan in a crises would be? Oh
> wait, that's not PC. The areas where the F-22 will really shine are
> those where the F-15 might have a difficult time and that's against a
> country with relatively large numbers of modern, high performance
> aircraft. And that means China, India and East Asia in general. For
> those who scoff at the idea of China ever being a threat you need to
> take off the blinders. The whole China / Taiwan thing is going to
> come to a head eventually and if we plan to stick to our word (fat
> chance these days) then we had better be prepared.

[Peter Kemp]

On Wed, 2 Jun 2004 13:42:25 GMT, "breyfogle" >
wrote:

>The F119 engines make sufficient thrust to allow high altitude supersonic
>cruise at a Mach somewhat less than Mach 2 while not requiring any
>significant change to the current fixed inlets. The tradeoff is a
>significant reduction in range.

I thought the requirement for adjustable inlets was to avoid the
supersonic shockwave impinging on the compressor and stalling the
engine. If so, then the thrust of the F-119 isn't oging to help at
all.

Peter Kemp

[breyfogle]

The F-101 produces enough thrust for Mach 1.2 to 1.25 and the shock is
stable somewhere in the inlet ducting. The F-119 should produce enough
extra thrust to increase the max Mach significantly. Sure, the shock front
moves aft as Mach increases and at some point the shock will reach the fan
and bad things happen. F-16's & F-18's reach 1.6 (1.8?) Mach with fixed
inlets.

"Peter Kemp" > wrote in message
...
> On Wed, 2 Jun 2004 13:42:25 GMT, "breyfogle" >
> wrote:
>
> >The F119 engines make sufficient thrust to allow high altitude supersonic
> >cruise at a Mach somewhat less than Mach 2 while not requiring any
> >significant change to the current fixed inlets. The tradeoff is a
> >significant reduction in range.
>
> I thought the requirement for adjustable inlets was to avoid the
> supersonic shockwave impinging on the compressor and stalling the
> engine. If so, then the thrust of the F-119 isn't oging to help at
> all.
>
> Peter Kemp

[Jim Yanik]

Why bother converting a B-1 into a supersonic reconnaissance plane,when
they could reactivate the SR-71's? What advantage would there be?

--
Jim Yanik
jyanik-at-kua.net

[Paul F Austin]

"Jim Yanik" wrote in
>
>
> Why bother converting a B-1 into a supersonic reconnaissance plane,when
> they could reactivate the SR-71's? What advantage would there be?

"R" is apparently from "Rengine" not "Reconnaissance". The article describes
responses to an Air Force RFI for improved bombers.

[Scott Ferrin]

On Wed, 2 Jun 2004 21:23:08 GMT, "breyfogle" >
wrote:

>The F-101 produces enough thrust for Mach 1.2 to 1.25 and the shock is
>stable somewhere in the inlet ducting.

It sounds like you're missing the point. The F101 has enough power to
take the B-1 to Mach 2.2 and had done so prior to the inlet redesign.
Since the inlet redesign it can't go there anymore. Period. More
thrust isn't going to get you a higher top speed. More thrust
(particularly dry thrust) will get you more speed for a given weight
but if the inlets weren't an issue they'd have been fixed from the
start or else a clean B-1B would still be able to hit Mach 2+. It
can't.



> The F-119 should produce enough
>extra thrust to increase the max Mach significantly.

If you are comparing dry thrust to dry thrust then sure.



> Sure, the shock front
>moves aft as Mach increases and at some point the shock will reach the fan
>and bad things happen. F-16's & F-18's reach 1.6 (1.8?) Mach with fixed
>inlets.

The B-1's speed is limited by the inlets, not the engines. True, the
F119 is optimized for higher speed than the F101 but the inlets will
still make a difference.






>
>"Peter Kemp" > wrote in message
...
>> On Wed, 2 Jun 2004 13:42:25 GMT, "breyfogle" >
>> wrote:
>>
>> >The F119 engines make sufficient thrust to allow high altitude supersonic
>> >cruise at a Mach somewhat less than Mach 2 while not requiring any
>> >significant change to the current fixed inlets. The tradeoff is a
>> >significant reduction in range.
>>
>> I thought the requirement for adjustable inlets was to avoid the
>> supersonic shockwave impinging on the compressor and stalling the
>> engine. If so, then the thrust of the F-119 isn't oging to help at
>> all.
>>
>> Peter Kemp
>

[WaltBJ]

FWIW ISTR the Mne on the F102A was M 1.5 because of its simple
intakes. Again FWIW the only way you could fet anywhere near 1.5 was
in a dive . . .1.3 level was attainable, though.
Walt BJ

[[email protected]]

Since the standardized designation system is gone out the window now
anyway, I won't be surprised if the R is for recon, instead of calling
it an RB-1D(?). ISTR back in the early-mid '80s a B-1C was proposed as a
long range interceptor for Soviet bombers to be equipped with the F-14
radar & Phoenix missiles in the bays & be operated by ADC. That was in a
news blurb in AWST way back then.

[Paul F Austin]

> wrote
> Since the standardized designation system is gone out the window now
> anyway, I won't be surprised if the R is for recon, instead of calling
> it an RB-1D(?).

You might actually_read_the article in AvWeek.. The USAF is clearly in the
market for better bombers, not recce platforms.

[Jeb Hoge]

Scott Ferrin <> wrote in message >...
> On Wed, 2 Jun 2004 21:23:08 GMT, "breyfogle" >
> wrote:
>
> >The F-101 produces enough thrust for Mach 1.2 to 1.25 and the shock is
> >stable somewhere in the inlet ducting.
>
> It sounds like you're missing the point. The F101 has enough power to
> take the B-1 to Mach 2.2 and had done so prior to the inlet redesign.
> Since the inlet redesign it can't go there anymore. Period. More
> thrust isn't going to get you a higher top speed. More thrust
> (particularly dry thrust) will get you more speed for a given weight
> but if the inlets weren't an issue they'd have been fixed from the
> start or else a clean B-1B would still be able to hit Mach 2+. It
> can't.

*ponders* I wonder if there's any new "lessons learned" data from
F-22/35 development that might permit another inlet redesign on the
Bone. The AF might be able to both get the speed and stay stealthy
with a new, more sophisticated inlet design based on the technology
and experience they've gained in the past ten years or so.

[Bob McKellar]

Paul F Austin wrote:

> > wrote
> > Since the standardized designation system is gone out the window now
> > anyway, I won't be surprised if the R is for recon, instead of calling
> > it an RB-1D(?).
>
> You might actually_read_the article in AvWeek.. The USAF is clearly in the
> market for better bombers, not recce platforms.

But think of the fun when the fifth version ( fourth modification ) is
introduced.

Bob McKellar

[breyfogle]

One of the factors limiting installed thrust is the ability of the duct to
flow a maximum amount of air mass. I don't see any particular reason why a
different engine (optimized for a different Mach/Altitude) might not be able
to produce more thrust when installed in the same nacelle, flowing the same
mass of air. I'm not an engine person but seems like increasing the
compression ratio, changing the bypass ratio, increasing the turbine temp
and increasing the fuel flow might all increase the thrust level for a given
mass flow rate. Certainly, not every turbofan engine produces the same
thrust when flowing the same mass of air.

<Scott Ferrin> wrote in message
...
> On Wed, 2 Jun 2004 21:23:08 GMT, "breyfogle" >
> wrote:
>
> >The F-101 produces enough thrust for Mach 1.2 to 1.25 and the shock is
> >stable somewhere in the inlet ducting.
>
> It sounds like you're missing the point. The F101 has enough power to
> take the B-1 to Mach 2.2 and had done so prior to the inlet redesign.
> Since the inlet redesign it can't go there anymore. Period. More
> thrust isn't going to get you a higher top speed. More thrust
> (particularly dry thrust) will get you more speed for a given weight
> but if the inlets weren't an issue they'd have been fixed from the
> start or else a clean B-1B would still be able to hit Mach 2+. It
> can't.
>
>
>
> > The F-119 should produce enough
> >extra thrust to increase the max Mach significantly.
>
> If you are comparing dry thrust to dry thrust then sure.
>
>
>
> > Sure, the shock front
> >moves aft as Mach increases and at some point the shock will reach the
fan
> >and bad things happen. F-16's & F-18's reach 1.6 (1.8?) Mach with fixed
> >inlets.
>
> The B-1's speed is limited by the inlets, not the engines. True, the
> F119 is optimized for higher speed than the F101 but the inlets will
> still make a difference.
>
>
>
>
>
>
> >
> >"Peter Kemp" > wrote in message
> ...
> >> On Wed, 2 Jun 2004 13:42:25 GMT, "breyfogle" >
> >> wrote:
> >>
> >> >The F119 engines make sufficient thrust to allow high altitude
supersonic
> >> >cruise at a Mach somewhat less than Mach 2 while not requiring any
> >> >significant change to the current fixed inlets. The tradeoff is a
> >> >significant reduction in range.
> >>
> >> I thought the requirement for adjustable inlets was to avoid the
> >> supersonic shockwave impinging on the compressor and stalling the
> >> engine. If so, then the thrust of the F-119 isn't oging to help at
> >> all.
> >>
> >> Peter Kemp
> >
>

[Keith Willshaw]

"breyfogle" > wrote in message
...
> One of the factors limiting installed thrust is the ability of the duct to
> flow a maximum amount of air mass. I don't see any particular reason why
a
> different engine (optimized for a different Mach/Altitude) might not be
able
> to produce more thrust when installed in the same nacelle, flowing the
same
> mass of air. I'm not an engine person but seems like increasing the
> compression ratio, changing the bypass ratio, increasing the turbine temp
> and increasing the fuel flow might all increase the thrust level for a
given
> mass flow rate. Certainly, not every turbofan engine produces the same
> thrust when flowing the same mass of air.
>

The problem is that the flow regime for subsonic flight is entirely
different than for supersonic flight.

The bottom line is that turbofan engines cant cope with
supersonic flow so above Mach 1 you need to slow
the flow. Trouble is this makes it inefficient at subsonic
speeds. To get round this some aircraft use variable inlet
geometries but this conflicts with stealth requirements.

The B-1A had the variable geometry required for supersonic
flight, the B-1B does not. You'd need to redesign the entire
inlet system to provide high supersonic performance.

Keith

[[email protected]]

If I subscribed to AvWeek, I _would_ read the article.

[Paul F Austin]

> wrote in message
...
> If I subscribed to AvWeek, I _would_ read the article.
>
Most University libraries and large city libraries carry it. It's worth
while.

[Paul F Austin]

"Keith Willshaw" > wrote in message
...
>
> "breyfogle" > wrote in message
> ...
> > One of the factors limiting installed thrust is the ability of the duct
to
> > flow a maximum amount of air mass. I don't see any particular reason
why
> a
> > different engine (optimized for a different Mach/Altitude) might not be
> able
> > to produce more thrust when installed in the same nacelle, flowing the
> same
> > mass of air. I'm not an engine person but seems like increasing the
> > compression ratio, changing the bypass ratio, increasing the turbine
temp
> > and increasing the fuel flow might all increase the thrust level for a
> given
> > mass flow rate. Certainly, not every turbofan engine produces the same
> > thrust when flowing the same mass of air.
> >
>
> The problem is that the flow regime for subsonic flight is entirely
> different than for supersonic flight.
>
> The bottom line is that turbofan engines cant cope with
> supersonic flow so above Mach 1 you need to slow
> the flow. Trouble is this makes it inefficient at subsonic
> speeds. To get round this some aircraft use variable inlet
> geometries but this conflicts with stealth requirements.
>
> The B-1A had the variable geometry required for supersonic
> flight, the B-1B does not. You'd need to redesign the entire
> inlet system to provide high supersonic performance.

That's certainly possible and even for a fixed inlet. If the inlet is
optimized for M2, then off design point operation may suffer somewhat but
Boeing is suggesting a supercruiser bomber in any case.

[Steve R.]

"Bob McKellar" > wrote in message
...
>
> But think of the fun when the fifth version ( fourth modification ) is
> introduced.
>
> Bob McKellar
>


B-1RD? ;o)
Steve R.

[Alan Minyard]

On Wed, 2 Jun 2004 23:50:43 +0000 (UTC), Jim Yanik > wrote:

>
>
>Why bother converting a B-1 into a supersonic reconnaissance plane,when
>they could reactivate the SR-71's? What advantage would there be?

SRs are *very* expensive to operate and maintain. The savings achieved
by using the B-1 would soon pay for themselves.

Al Minyard

[Jim Yanik]

Alan Minyard > wrote in
:

> On Wed, 2 Jun 2004 23:50:43 +0000 (UTC), Jim Yanik >
> wrote:
>
>>
>>
>>Why bother converting a B-1 into a supersonic reconnaissance
>>plane,when they could reactivate the SR-71's? What advantage would
>>there be?
>
> SRs are *very* expensive to operate and maintain. The savings achieved
> by using the B-1 would soon pay for themselves.
>
> Al Minyard
>

At a shorter range and slower speed,and more vulnerability,not to mention
re-engineering costs that would be better spent.

--
Jim Yanik
jyanik-at-kua.net

[Michael Kelly]

I've seen two proposals to this effect, makes for some interesting
reading... It is plausible, but the real question is if the money for
upgrades would be better spent on systems other than the engines. FWIW
reengining does bring interesting new capabilities.

Michael Kelly
Bone Maintainer

Paul F Austin wrote:
> From this week's AvWeek. Boeing responded to an Air Force RFI against a
> requirement for improved bombers by suggesting re-engining the B-1 fleet
> with F-119 engines with the following characteristics: Mach 2 cruise, 3000
> mile radius, 60,000 foot ceiling (with a couple of hours loiter).
>
> Is this plausible? From others in this group, I though the B-1 was marginal
> above 30,000 feet.
>
>

[Michael Kelly]

Scott Ferrin wrote:
> 3. The B-1A could do Mach 2.2 at 60,000ft so the basic airframe is
> capable of it. Comes down to the engines, intakes, weight. The
> article raised more questions than it answered.

Weight, fixed inlets and RCS vanes. Unfortunately, everything I've seen
on this is not for public consumption :(

Michael Kelly
Bone Maintainer

[Michael Kelly]

breyfogle wrote:

> The F-101 produces enough thrust for Mach 1.2 to 1.25 and the shock is
> stable somewhere in the inlet ducting. The F-119 should produce enough
> extra thrust to increase the max Mach significantly. Sure, the shock front
> moves aft as Mach increases and at some point the shock will reach the fan
> and bad things happen. F-16's & F-18's reach 1.6 (1.8?) Mach with fixed
> inlets.

Know some pilots who swear they've gone 1.4, but only for very short
times. The biggest limiting factor are those two big RCS vanes in each
inlet.

Michael Kelly
Bone Maintainer

[Michael Kelly]

Bob McKellar wrote:

> But think of the fun when the fifth version ( fourth modification ) is
> introduced.

Heck, we're already at the Block E configuration which entains quite a
few changes to the systems.

Michael Kelly
Bone Maintainer


>
> Bob McKellar
>