GE F120 - outdated/a good idea? (JSF)
Alex Stoll
service, won't it be basically a 20-year old engine? That doesn't make
sense, to use a 20-year old engine in a state-of-the art new fighter (to me,
at least). I know the F119 is also as old, but it's being developed further
for the F-22 (isn't it?). 20 years is a long time in aviation.
--
Alex Stoll
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BSchiltz
cycle, new Rolls Royce fan,Philips FADEC from the Netherlands and other
classified goodies.
Perhaps GE and the armed services feel that the 'core' has much potential for
the future but maybe they should derive an engine from NASA's IHPTET program
instead. The Air Force Academy has a
YF-120 here in Colorado, I've seen it, Jesus what a monster much bigger than an
F-100
Alex Stoll
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Alex Stoll
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frog
Alex Stoll wrote:
>
> Really, no more variable cycle? Why not?
> --
> Alex Stoll
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> http://www.Alex.AlexStoll.cjb.net/
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> BSchiltz <bsch...@aol.com> wrote in message
> news:20001111005452...@ng-fw1.aol.com...
Ken Garlington
news:3A0E42...@wanadooacf.fr...
: And why a Philips FADEC??? [for 'new' F-120]
I don't know, but I can speculate. I believe that GE Aerospace made GE
engine controls until 1993, when it was acquired by Martin Marietta.
Lockheed Martin Control Systems was formed in 1995 as part of the
Lockheed-Martin Marietta merger. Although GE has continued to rely on them
for engine control systems support, they may have decided that it was time
to bring in more competition. The ability to support offsets may have also
been in their mind, although now that BAE SYSTEMS has purchased Control
Systems, that might be less of a factor in the future. (Frankly, I don't
know if buying from BAE SYSTEMS counts as an offset or not. I would guess
not, but who knows?)
mark
I didn't know that Philips makes FADECs.
Ken Garlington
: I didn't know that Philips makes FADECs.
I didn't, either. Here's the press release from their web site:
June 15, 1999
Philips joins the JSF F120 engine team
Philips Machinefabrieken announces that it has concluded an agreement with
the members of the Joint Strike Force F120 engine team (General Electric
(GE), Rolls-Royce (RR), and Allison Advanced Development Company (AADC))
under which it will form and lead a consortium of Dutch, Norwegian, and
Danish companies to join in the design, development, and manufacture of the
F120 propulsion system for the JSF Alternate Engine Program.
Philips Machinefabrieken is part of Royal Philips Electronics of the
Netherlands, and specializes in a wide range of production high-tech
machines and systems, and in the manufacture of aviation components.
"Given the participation of the Dutch, Danish and Norwegian governments in
the JSF Concept Demonstration Program in the U.S., Dutch industrial
participation with the JSF F120 team was a natural," said Jim McNerney,
president of GE Aircraft Engines, a business unit of General Electric Co.
"The proven technologies and performance within Philips and Dutch industry
and their healthy financial position and global reach will make them valued
team members."
Frans Bastiaanssen, CEO of Philips Machinefabrieken said: "Besides
significant growth opportunities in our global manufacturing network,
through this agreement we also get access to a wide range of advanced
technologies, which can find a wide application in other areas where Philips
Machinefabrieken is active such as the Semiconductor equipment industry."
The Philips Machinefabrieken consortium will be fully integrated into the
JSF-F120 team, and will develop world-class technologies to be applied to a
wide variety of F120 engine components. The consortium members will have the
opportunity to participate in other GE, Rolls Royce, and Allison programs.
Philips Machinefabrieken is the sole supplier of exhaust nozzle flaps and
seals for GE F110 fighter engines and is expanding its relationship into
other GE product lines. Philips Machinefabrieken also supplies the Inlet
Scrolls for the Allison 250 engine.
For further information please contact:
Philips Media Relations
Jeremy Cohen, tel: +31 20 5977213, email: Jeremy...@philips.com
Kurt R. Todoroff
last year. The F-120 appeared smaller than the F-100 (by my recollection). Of
course, I didn't pull out my measuring tape, just used my memory. I'd been out
of the TAC cockpit for 13 years.
Nevertheless, an impressive piece of work. Several of us Aero Propulsion major
types did a considerable amount of research on variable cycle gas
turbomachinery during our senior year Aero project (1978-1979). Two of us
wrote a 130 page paper on it. I pulled the paper out a few years ago and
looked at the striking similarities between it and the F-120.
I'd love to run the F-120 on the test stand for a couple of hours and then run
it in an F-22 or F-23 for a couple of hours!
Kurt Todoroff
shar...@aol.com
Remove "DELETEME" from my address to reply
Eric Biedermann
Does anyone know of a URL I can look at to find some detailed information on
the F-120 (from the ATF competition, not JSF) that gives project
background, some specs (estimated or otherwise), pics, etc? I've already
tried GE Aircraft Engines' website and did not find much info. Thanks!
Regards,
Eric
"Kurt R. Todoroff" <shar...@aol.comDELETEME> wrote in message
news:20001112142649...@ng-md1.aol.com...
> I saw the F-120 in the USAFA Aero Lab when I visited for my 20 year
reunion
> last year. The F-120 appeared smaller than the F-100 (by my
recollection). Of
> course, I didn't pull out my measuring tape, just used my memory. I'd
been out
> of the TAC cockpit for 13 years.
>
> Nevertheless, an impressive piece of work. Several of us Aero Propulsion
major
> types did a considerable amount of research on variable cycle gas
> turbomachinery during our senior year Aero project (1978-1979). Two of us
> wrote a 130 page paper on it. I pulled the paper out a few years ago and
> looked at the striking similarities between it and the F-120.
>
> I'd love to run the F-120 on the test stand for a couple of hours and then
run
> it in an F-22 or F-23 for a couple of hours!
>
>
Alex Stoll
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Maury Markowitz
news:20001112142649...@ng-md1.aol.com...
major
> types did a considerable amount of research on variable cycle gas
> turbomachinery during our senior year Aero project (1978-1979). Two of us
> wrote a 130 page paper on it. I pulled the paper out a few years ago and
> looked at the striking similarities between it and the F-120.
Forgive my ignorance, but can someone outline what variable-cycle is? Or
point me in the right direction? I'm familiar with regenerators, is this
something similar? I didn't find anything on topic in Google.
Maury
Keith Willshaw
"Maury Markowitz" <maury@remove_this.sympatico.ca.invalid> wrote in message
news:ElTP5.89538$78.28...@news3.rdc1.on.home.com...
see http://www.nap.edu/html/tech_21st/pl3.htm
Keith
Maury Markowitz
news:8up11u$981$1...@sshuraaa-i-1.production.compuserve.com...
>
> see http://www.nap.edu/html/tech_21st/pl3.htm
Thanks!
Maury
nx1...@my-deja.com
"Eric Biedermann" <bied...@uiuc.edu> wrote:
> Hello,
>
> Does anyone know of a URL I can look at to find some detailed
information on
> the F-120 (from the ATF competition, not JSF) that gives project
> background, some specs (estimated or otherwise), pics, etc? I've
already
> tried GE Aircraft Engines' website and did not find much info.
Thanks!
>
> Regards,
>
> Eric
>
> news:20001112142649...@ng-md1.aol.com...
> reunion
> > last year. The F-120 appeared smaller than the F-100 (by my
> recollection). Of
> > course, I didn't pull out my measuring tape, just used my memory.
I'd
> been out
> > of the TAC cockpit for 13 years.
> >
Propulsion
> major
> > types did a considerable amount of research on variable cycle gas
> > turbomachinery during our senior year Aero project (1978-1979). Two
of us
> > wrote a 130 page paper on it. I pulled the paper out a few years
ago and
> > looked at the striking similarities between it and the F-120.
> >
and then
> run
> > it in an F-22 or F-23 for a couple of hours!
> >
> >
website it could provide a link to other possible F-120 websites. Or you
could email lockheed-martin tactical aircraft division and politely ask
them for any public brochures they might have on the F-120, or you could
ask around at aviation week and space technology magazine.
Sent via Deja.com http://www.deja.com/
Before you buy.
Ken Garlington
: You could start by looking at www.jast.mil, this is the JSF official
: website it could provide a link to other possible F-120 websites. Or you
: could email lockheed-martin tactical aircraft division and politely ask
: them for any public brochures they might have on the F-120, or you could
: ask around at aviation week and space technology magazine.
I don't believe Lockheed Martin Aeronautics (nee Tactical Aircraft Systems)
has any brochures or other public information specifically on the F120
engine. You'd be much better off contacting GE.
I should point out that the YF120 engine was used on both the YF-22 and
YF-23...
Maury Markowitz
news:8up11u$981$1...@sshuraaa-i-1.production.compuserve.com...
> see http://www.nap.edu/html/tech_21st/pl3.htm
Sadly the picture is rather unclear. From the discussion in the text, I
have tried to piece together what it means.
1) 20 - 30% of the compressor flow is currently used as cooling air for the
turbine stages
2) by using a variable opening, we can adjust this figure from a high value
like the above, to a low value, or zero
3) as a result we can recapture all of this "lost" flow during the times
when we don't need it as the temperatures are low, like during cruise where
a 30% flow improvement would be significant (30% fueld savings?)
Did I get it right?
Maury
Keith Willshaw
"Maury Markowitz" <maury@remove_this.sympatico.ca.invalid> wrote in message
Well I'm no expert but I dont think so.
My understanding is that the efficiency of jet engines is highly
dependent on their operating regimes.
At Subsonic speeds high bypass ratio fans are a distinct advantage
moving larges masses of air at lower velocity leads to lower
losses due to turbulent flow etc.
In supersonic flight these are less efficient since moving
large masses of air at low velocity limits the top speed in
comparison with moving a lesser mass at a higher velocity
At Mach 3+ the ideal is the ramjet with no compressor/fan
stage
Most current engines are optimised for one regime and
are at best a compromise for other states. They use
some variable geometry factors such as movable inlet
cones to try to compensate but the engine itself operates
in the same manner throughout all flight conditions.
It's my understanding that the idea of the variable cycle engine is
that one can vary engine parameters like bypass ratio to
produce better efficiency for more flight conditions
Keith
Maury Markowitz
> It's my understanding that the idea of the variable cycle engine is
> that one can vary engine parameters like bypass ratio to
> produce better efficiency for more flight conditions
I'm familar with some of the older designs like the W67 and the French
design, and with some of the newer 80's revivals - is this what the diagram
was trying to show? If so, it's a terrible diagram!
Maury
Keith Willshaw
"Maury Markowitz" <maury_m...@hotmail.com> wrote in message
news:9R2Q5.80001$x6.16...@news20.bellglobal.com...
Hey dont shoot me I just found the article I didnt write it :)
Keith
nx1...@my-deja.com
from being licensed produced what other changes did it have.
Maury Markowitz
> Wasn't the J-67 a licensed version of the Rolls-Royce Olympus?, aside
> from being licensed produced what other changes did it have.
They were adapting it to bleed air from the compressor IP stages into the
rear of the engine, just like the J58 - I think the original Olympus did
this too (to lower pressure during startup IIRC). The installation was the
interesting part, there was a large "valve" in the inlet ramp that could
divert the air (all?) around the engine and directly into the tailcone.
The plan was that at high speeds the valve would close and the engine
would essentially be turned off (idle? off?). The air flowing around the
engine in the bypass duct would then flow into the afterburner and be
burnt - thus forming a ramjet. As a result the plane it was licensed for,
the F-103, was supposed to have a cruise speed of around M3.7 or so.
There are parallels with the J58 here, but it's been a LONG time since I
last looked at that engine. It also takes ip air from the turbine, right?
But I'm still not sure I understand how this applies to the F-120. Looking
at the diagram it appears they are taking a feed off of the hp stages of the
compressor, then feeding that outside of the turbine. But the diagram is so
unclear I can't see exactly what it's doing, it _looks_ like it's bypassing
the combustors and exiting out the rear in the afterburner stage through a
outer jacket, but that seems odd - is it burning there?.
And then there's those plates in the diagram aft of the turbine outlet
cones, what are they? If they close off the turbine outlet and bleed the air
back into the AB area then the setup is very similar to some of the 1980's
French designs I saw (well at least I saw them in a French mag, Science et
Vie IIRC), and perhaps the W67 too, but I'm not sure.
Maury
Maury Markowitz
news:20001112142649...@ng-md1.aol.com...
major
> types did a considerable amount of research on variable cycle gas
> turbomachinery during our senior year Aero project (1978-1979). Two of us
> wrote a 130 page paper on it. I pulled the paper out a few years ago and
> looked at the striking similarities between it and the F-120.
Kurt, any chance for a quick primer here? I'm familiar with some of the
basics, could you flesh out the details of the vari-cycle on the F-120?
Maury
Kurt R. Todoroff
Just as some aircraft employ variable geometry wing sweep designs that permit
the pilot to tailor, even optimize, aircraft configuration in flight, the
Variable Cycle Engine (VCE) reconfigures itself in flight for the ambient
flight conditions. The previous terminology that we used twenty years ago was
"Variable Area Turbine" or VAT. This is the key to understanding VCE.
Some of the previous persons who posted to this newsgroup were correct in their
assertion that aircraft and engines are optimized for a particular design
point. Therefore flight at any other point is not optimized, and thus, a
performance penalty is realized (thrust and fuel flow, and even reliability).
The VAT employs a variable geometry turbine inlet nozzle which controls the gas
flow parameters through the engine according to the ambient flight conditions.
(The turbine inlet nozzle is located aft of the combustor and forward of the
turbine.) A FAT, or "Fixed Area Turbine" employs a fixed geometry turbine
inlet nozzle. Being "Fixed Area" constrains the engine performance during "off
design" flight conditions. The FAT nozzle is very analogous to the fixed area
nozzle of non-afterburning engines, while the VAT nozzle is very analogous to
the variable area fully articulated nozzle of afterburning engines. In fact,
they serve the same purpose: to control the mass flow, temperature, and
pressure characteristics of the gas flow through the engine. At this point, if
you are mentally visualizing an orifice inside the engine (between the
combustor and the turbine) that increases and decreases in size according to
flight conditions (like the aperature in a camera), thus controlling the gas
flow (air and fuel) through the engine, then you are correct.
The advent of the Digital Electronic Engine Controller (DEEC) made the VAT or
VCE practical. The older hydro-mechanical engine controllers were limited to
monitoring and controlling very few engine and flight parameters. Today's
DEECs can monitor and control all of the engine parameters, and do so much
faster than the hydro-mechanical controllers. As such, the engine is less
susceptable to surge, stall, overspeeds, overtemps, etc. In fact, the DEEC can
run the engine much closer to the surge line than the hydro-mechanical units
could, which translates into greater thrust and lower fuel consumption and
greater reliability (especially at high angles of attack and low airspeed
conditions) through all flight regimes. The added task of monitoring and
controlling VCE parameters is no big deal for a DEEC (providing of course that
the software is written to include VCE algorithms). While we didn't address
the issue of engine controllers in our paper, I seriously doubt that those old
hydro-mechanical engine controllers could have managed a VCE sufficiently well
to maximize the inherent benefits of Variable Cycle. Given two identical VCE
engines, one with a hydro-mechanical controller and the other with the DEEC,
the second will outperform the first.
The obvious drawbacks to VCE are the additional moving parts that are required
to make this work, especially those that articulate within the environment of
the hot gas flow, and there associated weight. However, we have observed gas
turbomachinery reliability improve by an order of magnitude in twenty years.
(I'm making a reference to my personal experience with our early TF30s and
F100s.) Additionally, I did not experience nor did I know of a single TF30
nozzle failure in 1400 hours and 7 years of flying. The nozzle is exposed to
extremely high temperatures and G loading (i.e. bending) during articulation.
The USAF chose the F119 engine because it was a lower risk proposition. I
disagreed with their position based on empirical data and technical merit.
However, I fully agreed with their position based on the political risk. The
535 moronic pedants in congress can and do twist reality and history to suite
whatever agenda is politically popular and expedient for the moment. (Note
that CONgress is the opposite of PROgress.) (I apologize for stepping on my
soapbox for this brief moment.)
So, Maury, did I pass the test of "Quick Primer" or was the explanation not
quick enough?
> Kurt, any chance for a quick primer here? I'm familiar with some of the
>basics, could you flesh out the details of the vari-cycle on the F-120?
>
Maury Markowitz
> So, Maury, did I pass the test of "Quick Primer" or was the explanation
not
> quick enough?
Yeah, but...
So basically the description you give here is that there's another "choke
point" inside the engine behind the flame cans but in front of the turbine
inlet face. This brings up a few questions for me:
1) you don't mention materials in your primer, but it would seem to me that
this is as important as FADEC design due to the placement?
2) the diagram in question does not seem to illustrate such a choke, and
instead referrs to a hp-stage bleed from the compressor. Comments?
The URL for the diagram is http://www.nap.edu/html/tech_21st/pl3.htm, do a
find for "Figure 3.6 shows".
Maury
Kurt R. Todoroff
Materials technology is a sine quo non in gas turbomachinery.
I visited the web site in your message, however, it was not available. I
visited the web site from another posting and viewed the diagram in question.
It had insufficient resolution and clarity for me to discern any information on
the engine's operation.
> Yeah, but...
>
> So basically the description you give here is that there's another "choke
>point" inside the engine behind the flame cans but in front of the turbine
>inlet face. This brings up a few questions for me:
>
>1) you don't mention materials in your primer, but it would seem to me that
>this is as important as FADEC design due to the placement?
>
>2) the diagram in question does not seem to illustrate such a choke, and
>instead referrs to a hp-stage bleed from the compressor. Comments?
>
Maury Markowitz
> Materials technology is a sine quo non in gas turbomachinery.
Yeah, goes without mentioning I suppose.
> I visited the web site in your message, however, it was not available.
Oh, I must have cut the URL incorrectly. My appologies.
> It had insufficient resolution and clarity for me to discern any
information on
> the engine's operation.
Yeah, that was my conclusion too. It says it's from GE, so I wrote to them
for futher details of the original source.
Maury
Kurt R. Todoroff
Upon my return from my 20 year USAFA reunion last year, I sent email to GE with
several questions about the F120, since I had a wonderful discussion with the
Major in the Aero Lab who showed the engine to me. GE provided a very polite
response that stated that the nature of my questions, and the F120 in
particular were classified, therefore they could not answer my questions. Fair
enough. Good luck with your attempt.
I recall reading the Aviation Week & Space Technology articles on the first
flights of the YF-22 and YF-23. The F120 powered YF-23 flew so fast on its
first flight, that the USAF immediately classifed the speed. AW&ST reported
that the F120 powered YF-23 was the fastest of the four aircraft.
> Yeah, that was my conclusion too. It says it's from GE, so I wrote to
>them
>for futher details of the original source.
Maury Markowitz
> Upon my return from my 20 year USAFA reunion last year, I sent email to GE
with
> several questions about the F120, since I had a wonderful discussion with
the
> Major in the Aero Lab who showed the engine to me. GE provided a very
polite
> response that stated that the nature of my questions, and the F120 in
> particular were classified, therefore they could not answer my questions.
Fair
> enough. Good luck with your attempt.
Well as a Canuck I figure I can pretty much forget it then!
> I recall reading the Aviation Week & Space Technology articles on the
first
> flights of the YF-22 and YF-23. The F120 powered YF-23 flew so fast on
its
> first flight, that the USAF immediately classifed the speed. AW&ST
reported
> that the F120 powered YF-23 was the fastest of the four aircraft.
Thanks for the ref, I'll hunt it down.
Maury
Gregory Shaff
alpha capability than the YF-22. the 23 did not have negative alpha
capability from what I understand and that could be seen as the hot trailing
edge extends beyond that of the exhaust nozzle. This would also affect
recovery from very low speed, high theta pushovers. If the pilot were to go
into a 70 theta climb (just for example) and push hard over at 150 KCAS or
less, departure would be a definite possibility as there would be no
vectoring in that direction. On the other hand, in the YF-22 (and now the
F-22) when the pilot wishes to perform this manuever for whatever reason,
the vectoring would assist in departure resistance. But being a former
Northrop Grumman engineer, my heart lies with the YF-23. A pilot probably
wouldn't need these manuevers due to the inherent low RCS of the 23. I
would suspect (I have no knowledge of the RCS data) the YF-23 was stealthier
than the YF-22. Just look at the shape. The 22's tails are huge visual
targets and the nozzles are hidden in no way from beneath where the SAM is
looking. For those in the Southern California area, one of the YF-23s is
parked on the ramp at the West end of the Hawthorne airport on the 105
freeway. That's where Northrop Grumman does a lot of work.
Maury Markowitz wrote in message ...
>"Kurt R. Todoroff" <shar...@aol.comDELETEME> wrote in message
>news:20001115200445...@ng-cs1.aol.com...
>> Upon my return from my 20 year USAFA reunion last year, I sent email to
GE
>with
>> several questions about the F120, since I had a wonderful discussion with
>the
>> Major in the Aero Lab who showed the engine to me. GE provided a very
>polite
>> response that stated that the nature of my questions, and the F120 in
>> particular were classified, therefore they could not answer my questions.
>Fair
>> enough. Good luck with your attempt.
>
> Well as a Canuck I figure I can pretty much forget it then!
>
>> I recall reading the Aviation Week & Space Technology articles on the
>first
>> flights of the YF-22 and YF-23. The F120 powered YF-23 flew so fast on
>its
>> first flight, that the USAF immediately classifed the speed. AW&ST
>reported
>> that the F120 powered YF-23 was the fastest of the four aircraft.
>