MigBuster 2,884 Posted June 15, 2017 At 10:32 on Thursday June 15, Gripen E took off on its maiden flight, flown by a Saab test pilot. The aircraft (designation 39-8) left from Saab’s airfield in Linköping, Sweden and flew over the eastern parts of Östergötland for 40 minutes. During the flight, the aircraft carried out a number of actions to demonstrate various test criteria including the retracting and extending of the landing gear. http://saab.com/air/gripen-fighter-system/gripen/gripen/evolution/first-flight/ 1 Share this post Link to post Share on other sites
+Erik 1,815 Posted June 15, 2017 Did the E get an engine upgrade? From the last data sheets I remember seeing it had a minimal TWR of .81 and a single fan with 15K trust on an empty weight of 19K lbs. (from memory don't shoot me) I would like to see the Gripen realize better performance data for the job they are asked to do. That was my only complaint of the lumbering beasts they once were akin to the Mig 21. Share this post Link to post Share on other sites
+Coupi 4,405 Posted June 15, 2017 (edited) Did the E get an engine upgrade? From the last data sheets I remember seeing it had a minimal TWR of .81 and a single fan with 15K trust on an empty weight of 19K lbs. (from memory don't shoot me) I would like to see the Gripen realize better performance data for the job they are asked to do. That was my only complaint of the lumbering beasts they once were akin to the Mig 21. Hello Erik, Gripen E should get the F414G turbofan engine rated at 22,000lb (98kN). It features a new high-pressure turbine and a new six-stage, high-pressure compressor. We have this interesting document. Edited June 15, 2017 by Coupi Share this post Link to post Share on other sites
MigBuster 2,884 Posted June 15, 2017 Hello Erik, Gripen E should get the F414G turbofan engine rated at 22,000lb (98kN). It features a new high-pressure turbine and a new six-stage, high-pressure compressor. We have this interesting document. Some of those figures are out of date.....SAAB now advertise: http://saab.com/globalassets/commercial/air/gripen-fighter-system/pdf-files-download-section/facts/gripen-e-fact-sheet--en.pdf 1 Share this post Link to post Share on other sites
MigBuster 2,884 Posted June 15, 2017 Did the E get an engine upgrade? From the last data sheets I remember seeing it had a minimal TWR of .81 and a single fan with 15K trust on an empty weight of 19K lbs. (from memory don't shoot me) I would like to see the Gripen realize better performance data for the job they are asked to do. That was my only complaint of the lumbering beasts they once were akin to the Mig 21. The original ones advertised around 15K lbs weight with 18K lbs Max thrust. For the E looks like: Max Sea Level Static thrust rating increased ~22% Weight increased ~19% Might have a tad better T/W over the older one at max thrust. Mil thrust not advertised but claims of Supercruise at unknown parameters. Share this post Link to post Share on other sites
+Erik 1,815 Posted June 16, 2017 Thanks! Yeah still interesting platform but with that MTOW and TWR it's not quite as nimble as I had hoped. Pilots have their own philosophy on engine power. LOTS is GOOD, MORE is BETTER, TOO MUCH is JUST ENOUGH. Words to live by. Share this post Link to post Share on other sites
Caesar 305 Posted June 16, 2017 Something to remember about T:W is that it isn't static. Even the advertized thrust is probably the engine sitting on a stand, vice installed in the aircraft. Installed thrust is almost always lower (sometimes by several thousand pounds) at zero airspeed. Of the same token, as speed increases, thrust increases (to an extent), while increased altitude causes available thrust to decrease. As such, installed thrust at 0 airspeed might yield a <1:1 T:W, but the engine might provide a >1:1 T:W for a region of the envelope as the aircraft starts moving. It may be able to maintain >1:1 at certain airspeeds as altitude increases, but inevitably will drop below as altitude continues up. A published example in the open-source is the TF-30 for the F-14A. Advertized max thrust is 20,800lbs/engine. Once it is installed in the aircraft, at 0 airspeed, it produces only 17,077lbs/engine. As airspeed increases, thrust increases, and the engine maxes thrust output at sea level at .9M with 28,000lbs/engine (56,000lbs total), before bowing back down as the ramps deploy to full to stop supersonic airflow from stalling the engine, before starting to increase again (different inlets have different effects). So, a combat-weighted F-14A (~53,000lbs) achieves a better than 1:1 T:W at sea level from a little before to a little after .9M. As altitude increases, that thrust "curve" decreases, so at, say, 10,000 feet, the F-14A cannot achieve a 1:1 T:W at any airspeed. For the Gripen, then, with the new engine, (and even with the old), there's probably a region of the envelope where the aircraft hits or exceeds 1:1, and regions where it does not. Share this post Link to post Share on other sites
MigBuster 2,884 Posted June 16, 2017 Thanks! Yeah still interesting platform but with that MTOW and TWR it's not quite as nimble as I had hoped. Pilots have their own philosophy on engine power. LOTS is GOOD, MORE is BETTER, TOO MUCH is JUST ENOUGH. Words to live by. Although it doesn't look great on paper there is no way to really tell without getting hold of the flight test data to give an actual idea on performance........the thrust figures can be misleading (as Ceasars post) and there is no way to account for drag............let alone any with extra drag & weight of stores. Typically where you add more thrust to the same airframe you always have more T/D if not T/W thus flight test data reflects performance increase in acceleration & climb...........however increasing thrust also increases fuel consumption so they have had to hit a compromise and many pilots prefer the legs if the thrust is adequate. Of course Caesar where is the universal measure for >1:1 T/W ?........even the MiG-21bis flight manual shows it put out 21,825 lbs thrust at MACH 1 from a Emergency Thrust rating of 15,652 lbs at zero speed. I think the 1:1 T/W must be public and related to static thrust.............considering the actual thrust charts are very hard to get hold of / are never published outside the OEM. Share this post Link to post Share on other sites
Caesar 305 Posted June 16, 2017 Typically the way I see it reported in the open source is static thrust against a given aircraft weight (i.e., the thrust rating of the engine on a stand, uninstalled, at 0 airspeed). This is misleading because of the dynamic nature of engine thrust. Sometimes some of the numbers are made public; for example, the F/A-18C (F404-GE-402) and F/A-18E (F414-GE-400) installed outputs were partially published in a GAO report during the whole "is the F/A-18E/F actually worth the money" debate of the early-mid 90s. Outputs around max sustained turning velocity (between .8 and 1.2M-1.6M depending on altitude) for altitudes of sea level, 5,000ft, 20,000ft and 40,000ft were published and should be pretty eye opening for folks who heretofore thought of thrust as static. What is the T:W of the F/A-18E at combat weight at 40,000 feet and .9M? 0.27:1! And yes, drag is another big performance inhibitor, not just in terms of max speed, but general fighter performance as well (sustained turning, acceleration, etc.). Share this post Link to post Share on other sites