According to GE, up to 20% increase in power output. The planned result was a 31% reduced intercept time to climb.
27% reduced acceleration time at even very high altitudes to mach 1.6.
A 2% increase in sustained G forces (likely heavily improving specific excess power, though). Note the conditions are 10k meters and at a specific speed.
I was only remembering peak thrust, so I forgot that the GE-400 has more thrust drop at high speed. Yes, the ~20% increase is correct.
Your source is a review of F404 engines and their plans to continue improving them. It’s from January 1991, a year before the F404-GE-402 engines were fitted to the Hornet. Perhaps not representative of the actual 402 performance.
F404-GE-402 Enhanced Performance Engine (EPE).
F404-GE-402 EPE was defined in response to customer in-
terest in improved F/A-18 time-to-climb and combat performance and
will become the standard F/A-18 powerplant beginning in 1992. The
engine has so far been specified for U.S. Navy, Swiss, Kuwaiti, and Korean Hornets. The -402
model will be rated at 17,700 lb (79 kN) thrust at sea level
static conditions and will provide up to a 10-20 percent increase in installed thrust over the -400 model in key areas of the envelope, providing significant performance improvement
for the F/A-18 at key combat conditions as shown in Fig. 12.
Full-Scale Development is being executed under a unique
partnership arrangement between McDonnell Douglas,
GEAE, and the U.S. Navy whereby development costs, hardware, and engine/aircraft testing are shared by the three parties. The U.S. Navy is the U.S. Government authority for
specification requirements and production qualification.
We know this is true, because the actual -402 performance is higher than what is shown in that document. Unfortunately, while those newer documents are available on google… they are not permissible for sharing on the forum so we can’t really discuss exactly how much the -402 is superior to the RM12.
It is also the reason Gaijin thinks the RM12 should have higher thrust, since the temperature increase for the RM12 was 190 degrees (for very short duration), and the aforementioned document states +175 for the -402… in reality the -402 was improved to +200 degrees nominal among a variety of other further enhancements.
The GAO report does give us accurate installed thrust for mach 0.8 - 1.2 for the -402, to which the RM12 should be less but in-game it is more.
Except your source shows the RM12 as clearly better than the -402
Also, the GAO report you mention claims a figure of 17,754lbs uninstalled thrust for the 402 engines. It makes no mention of the RM12.
They sure do. SAAB clearly paid them to do so. Gripen must be the best!
The already in production RM12 has higher static thrust ratings than what was planned for the -402, that doesn’t mean it produces a better dynamic thrust curve.
Additionally, as I said, the -402 used the best improvements of the RM12 and made further enhancements. It’s simply a superior motor.
Correct, it states the same unclassified quote for static thrust for the -402 as that was the goal. I’ve already demonstrated that the -402 produces up to 20% more thrust than the -400, with a curve that puts the engine at nearly 20,000 lb-f depending on speed and altitude.
99% of public USAF / NAVAIR documentation was skewed. For example, AMRAAM sources claim “20+” miles range, or that it is 345+ pounds when in reality the AIM-120A missile is only 326 lbs according to newer information and has up to 60nm range depending on conditions.
There are of course a myriad of other examples where they state the thrust to weight of a fighter as less than 1:1 but the dynamic thrust is actually closer to 1.5:1 in conditions where that would truly matter. Building a strawman based on the idea that the RM12 is a superior engine solely due to a higher uninstalled static thrust ratings is… interesting to say the least.
So what im hearing is it can’t be better casue i say so
What you should be reading is that they are temperature limited, and we know the -402 has higher temperature limits and improved airflow internals. The higher flow fan on the RM12, according to GE, only provides an improvement in performance at very high altitudes when the fighter is traveling at slower airspeeds. The “top left” of the thrust by altitude and airspeed chart.
To spin this discussion that direction with the aforementioned strawman is to ignore this very important anecdote from the materials given. Again… an improvement in static uninstalled thrust due to the higher flow fan at standstill airspeeds will not net an improvement in dynamic installed thrust when the engine is temperature limited… and has a lower temp limit than the -402. This is explained in the document, as I mentioned. The plan was to produce the EPE (-402) prior to the introduction of the RM12, and it instead utilized common components and went on to have further enhancements made.
To further the point, the RM12 is only able to handle +190 degrees temperature increase over the F404-GE-400 for a very limited amount of time. The F404-GE-402 can handle a +200 degrees increase in temperature limit for the duration of its’ expected 2000 hour before overhaul limit.
To double back on the fact that the -402 exceeded the 17,700 lb-f uninstalled thrust goal… they originally thought it would only be possible to increase the temp limit by +175 degrees, and in the end increased it by +200 degrees. The thrust cap is directly restricted by temperature limitations.
We love going in circles don’t we
General Electric Aircraft Engines and Volvo Aero Corporation developed the
RM12 derivative engine from the F404 to power the JAS 39 Gripen for the Swedish Air
Force. The RM12 had a projected dry rating of 12,150 lb (54.04 kN), or 17,800 lb (79.18
kN) with a new Volvo/GE afterburner, which gives the all-altitude supersonic
performance even with fixed rectangular intakes. The RM12 (F404-400) is a two-shaft
augmented low-bypass ratio turbofan with a three-stage fan and a seven-stage
compressor, both incorporating variable stators and driven by single-stage turbines. The
afterburner, which boasts a fuel activated, variable-area nozzle is fully modulating form
minimum to maximum augmentation. GE to Volvo supplies 60 percent of engine
components, but Swedish design input has been such that many RM12 changes are
featured in the newest F404-402 engines. The RM12 is optimized for single-engine
mission with up to 10 percent increase in fan airflow, LI birdstrike resistance, improved
turbine materials and a combat performance rating. A new Full Authority Digital
Electronic Control (FADEC) is being incorporated in 2000. The RM12 delivers rapid
throttle response, unrestricted throttle movements and smooth afterburner light-offs. In
addition, the engine is highly reliable and has exceptionally high tolerance to inlet
distortion. South Africa has recently selected the RM12-powered JAS 39.
What is the source for that and when was it published? Seems they had a similar power goal for the RM12 to the GE-402 but as we know, the static uninstalled thrust is actually higher at over 18,000 lbf.
MODERNIZATION OF THE CZECH AIR FORCE
Naval Postgraduate school, Monterey, California, US NAVY
author : cpt. Vaclav Vlcek Army of the Czech Republic, Eng., Military Academy
While the naval postgraduate school usually has good well sourced information, that excerpt doesn’t seem to be well sourced. The references at the bottom are simply a number of websites but without specific pages in mind… such as just saying “boeing.com”. I’d like to know where they got the thrust ratings for the RM12 in this case because they also called it the -400 in parentheses.
^^^^
What I said isn’t my opinion, it is explicitly what is shown with the sources mentioned above. Please, stop trolling.
I’m simply stating that the quoted source from wasa has erroneous information and isn’t well sourced.
That is everything that you disagree with
It states the RM-12 is the F404-400 and has lower thrust figures for it than other available primary information. The source would support what I have been saying, but I’m telling you it’s not valid for the reasons above
So now, stop trolling.
