On the SAAB Gripen
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I’m going to leave a runner of anything I feel needs attention. I’ve spoken with Ned and Gavin, this is more of a cork board.
The Gripen is the backbone of the scandinavian airforces, and the current fruit of their engineers, it is only right and fitting that the jet should get the same treatment as the theater itself, as it should be the heavy lifter in these scenarios.
All versions of the gripen A were outfitted with FLIR. All have a thrust reverser, to assist with the STOL ability, a loaded for bearing GRIPEN can be from dead stop to wheels up in 800M. According to the swedish press, the gripen can achieve mach one with no burner 300 ASL less than 10km from wheels up.
These are the qualities of this plane, advanced onboard EWS, low level low heat high acceleration (to avoid soviet era and russian IADS), an electronically gated fuel pump, that will allow a pilot as much freedom while calculating a homeplate reserve (the best way to do this in falcon is to restrict full burner fuel usage to no more than 4.0kgs a second at full burner.) The swedish ordered a modern lightweight turn fighter that has low maintenance and high reusability/ flight economy. the jet can respond defensively at high speeds and low altitudes to a variety of threat environments.
Low level low fuel consumption acceleration is the hallmark of this puppy.
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and an aesthetic suggestion : the canards should be at full deflection during take off, similarly to the aft of a tomcat durring catapult.
The Gripen takeoff is something to behold.
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The Gripen is the backbone of the scandinavian airforces.
Actually, only Sweden uses the Gripen in Scandinavia…
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Of all that, only thing you had to say was a one line correction?Oh Internet.
Which other modern fighter was developed by a Scandinavian state and is currently being exported? Eurofighter typhoons are being replaced with gripens in Austria as well.
The wording I used I believe represented my tone well, the gripen is on the main menu splash for a reason.
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Gripen does not have reverse thrust. Maybe you are confusing it with Viggen?
It certainly is a quality aircraft though, regardless of nitpicking! -
Unfortunately, the Gripen C and D that we are calling our two models are a bit short in many respects. I recognized that from the start and yes they are intended to be a center-piece for Nordic even though we have other models in the DB that are much better, definitely.
Please keep in mind that Nordic was done on a shoestring with the bulk of model building falling on one team member (ccc) and then us scrambling, for other stuff that could be used or might work by other generous folks like Tomkatz, Qawa, and Metalhead. There are a lot of a/c in Nordic that are rather low poly - definitely not the stuff of legends but they get the job done and fill a space until better things come along. The limitations of the models also dictate how much we can do with them. CCC and I both agree that developing low-poly models are really intended as placeholders for much better models that we anticipate the community will eventually develop for us or that can come from within the BMS Team proper. So, low poly models aren’t going to get “the works.” That is sort of a waste of time.
I did receive permission to use an excellent JAS-39C by Anders Lejczak but it remains in an unfinished state, waiting someone with the skills necessary to animate it. I can skin it and perhaps with some assistance from someone more knowledgeable about its functions than myself we can really tweak out the flight model to replicate the Gripen more closely.
Lastly, keep in mind there are going to be other limitations imposed by the simple fact this is an F-16 sim . . . not a Gripen sim. So, really what we are doing is trying to get an F-16 to look and act like a totally different a/c.
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@ude:
Gripen does not have reverse thrust. Maybe you are confusing it with Viggen?
It certainly is a quality aircraft though, regardless of nitpicking!read that it uses exhaust fans on touchdown to generate reverse thrust.
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Note from what I can tell by the model I have…but I could conjecture that it can aerobrake like a bat by flat-plating those canards…
…love that little airplane!
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Re: Gripen features. If folks can post up features missing from Gripen I can check to see how much of that is just a simple editing of flight model script. Those are pretty easy to do and can result in some improvements that don’t require upgrading a 3d model. I think thrust reverse should be possible - I can look at the Viggen and see how it is setup. Not sure about the canards, usually the linking up of airbrakes with the actuation of the stabilators/candards should be doable depending on switches. But, reworking the model might need ccc to revisit it.
Re: Phantom: might need to look at adjusting some FM data like I did with the Gripen to make it more stable. If the wings are doffed/switced for folding then it should be doable and needs something in the FM too.
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the biggest characteristic that should be modeled, from everything I’ve read are it’s main three flight dynamics, low altitude high acceleration, electronically gated fuel consumption, extremely short loaded for combat takeoffs (less than or no greater than 800m) and landings, In my opinion.
It should perform greatly and have amazing acceleration close to the deck, the airbrake, the energy retention and diffusion of the aircraft under 5000 SL should be a more subtle focus. I watched a gripen pilot come in for short final .5NM final, one hard right final turn, went from 3,500 to 400, airbrake full the entire maneuver, called final .2 from the threshold all this in one big corkscrew, on flare 10 feet IAS went from 200 to 140 in under 1 second. This was in a GRIPEN A simulator, the video is controlled. The jet was at a complete stop in under 300 meters.it is the most impressive STOL in a modern jet I have ever witnessed.The field was a randomly selected two lane highway, by one of the trainers, the threshold was an intersecting highway. There are more than likely, at this point, publicly released simulator videos of GRIPEN C’s in the wild, for your own reference. The video I reference had weapons and fuel details as well as deployments so it’s unavailable as of now.
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Lewis,
One of the main drawbacks to the Gripen is lack of detailed performance data. So, some of this might require some extensive tweaking and testing of the existing flight model. BMS makes use of a secondary AFM (accurate flight model) which includes some additional parameters - but ultimately this would require systematic testing and tweaking over the entire fight envelope since adjusting one parameter may adversely affect another and thus one might find themselves chasing the solution around never quite capturing the extremes of performance. To some extent I think we may even try to consider some “cheats” to simulate the performance given the available parameters.
The landing simulation you have described seems consistent with the Swedes concept of using dispersed locations . . . small re-arm/refuel/maintenance stations integrated into the common road network. STOL seems like a necessary flight characteristic and makes being able to deny the Swedes runways nearly impossible.
I am not familiar with the electronically gated fuel consumption. What exactly does this do? Does this make the Gripen a super fuel efficient flyer? I believe the Falcon flight model controls fuel flow in a rather basic manner using a fuel consumption “factor” . . . so having an idea of fuel rate in lbs/min to adjust from would be use and that perhaps will bring the actual fuel consumption closer to reality. What I did was looked up the engine for the Gripen - which i think is a slightly modified F-18 engine . . . with a slightly improved fuel consumption rate that is what I used but if the Swedes have developed some additional software to better manage fuel consumption I just need to know what that translates into real fuel consumption in non-afterburner rates lbs/min. You can check the current fuel rate for yourself using BMS Editor . . . clicking on the vehicle record it will list the value - you can then determine if I have a good fuel consumption rate or it needs some adjustment.
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yes my friend, I agree with the philosophy you are taking, it seems to be the best approach with the limited ecology of solutions available. I’m not good rooting around in those files, but from what I can surmise, the gripen will not suck more than 4.0 kg/s in any instance, that means yes, it is very fuel efficient, and the engine works best at lower altitudes, between the 100 to 3500 ASL the thing should basically be a rocketship. the gripen is fully supercruise capable, even the a version, even with external stores,which is impressive in and of itself.damn.this is because the aero design is one of the LOWEST DRAG RATIOS IN MANS AVIATION HISTORY. of note, originally estimated at 10/1 flight to maintenance hours, the gripen has actually posted an unprecedented 3.5 man hrs to every 1 hr of flight time, not that that matters to the sim. original estimate was 2,500 american per hr, it’s actually worked out to be 1,113.50 american as of now. costs the same as an f-16 d blk 60
on takeoff, full loaded rotation speed is 149. full dry power loaded will give you 12,000 lbs around 54 kilo-newtons and wet will get you around 18,250lbs or about 81.00 kN. long takeoff average 18 seconds from roll to wheels up fully loaded, 3 tanks and 2 gbu 24s. with no stores full load internal the gripen can be wheels up and climbing at an optimal speed of 340 MPH ground reference and achieve 3000 ASL in 12 seconds from roll. DAMN.
this is key on the brakes logic " a differential braking system engages only after the nose wheel makes contact, and deflects the canards , as well as all control surfaces including the airbrake to maximum drag as well as deflecting the nose down to an auto hold of -5 degrees" this means the jet will stop very quickly. the braking logic allows the pilot to apply full brakes before actually extending the gear, which allows some feel and preparation for the STOL profile.all the gripen pilots love it. I would say, snuff the idea of the blowback effect, it’s basically used as a landing cushion, and focus on the drag effect once on the ground.
This is all first party data from SAAB
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I believe currently fielded Gripen are equipped with a variant of the F404 engine similar to early Hornets…but from what I can Google there was a demonstrator that was equipped with a variant of the F414, found in the Super Hornet…which ought to give it some real kick, if future versions are fitted.
Should think the fantastic STOL performance is mostly due to the canard configuration and the aircraft’s small size and light weight…would like to own one - I think it would fit in my garage…
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the variant of the engine used is not just a single output hornet engine, it was re-engineered from the floor up to give more stability and more thrust in a single engine compact airframe, which included shortening it, and taking weight off, among other things.
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one of the coolest things I’ve read about that SAAB disclosed is the auto combat modes for both creating rear aspect shots, and fighting with the gun in close. I won’t expound on that here, but they are really cool technologies, something that would be sweet to have in an actual GRIPEN dedicated simulation, maybe someday over the rainbow. Worth a read.
another cool little thing, it has a engine swapping mount, so, if there is a russian invasion and the flight line needs to be pumping out aircraft constantly, well guess what, don’t brake for cool down, drop that hot engine on the ramp and a team of 3 men can mount a new one in less than 10 minutes due to the modular housing.
a big reason you cannot apply hornet logic to the gripen in terms of engine is the weight and drag ratios of the aircraft are vastly different. you’re comparing the thrust to weight ratio of a porsche and an s 10 because they are both mid engine in a sense. The gripen has the lowest operational drag co efficient of any modern airplane, classified or no, as well as sporting one of the lowest for bare weights, smallest masses, etc etc etc. It’s a thrust to weight ratio kingpin, not a hornet, noweher even close, the hornet maritime structural and even the gear may as well JUST be an entire gripen, damn near. the volvo rm12 is simply based on the 404-400, it isn’t one. In fact the PIO problems in the POC phase were the main reason for that being redeveloped basically from brick one. all they kept was the access and the license. they redesigned the intake baffle pump exchange compressor post etc etc etc, at that point it’s just like someone asking how hard is it to put a new processor motherboard and chipset into a pc, just buy a new one, it’s cheaper…it’s basically an entirely different engine, this whole thought process influences the modular dropout as well.
another thing I’ve noticed is the loadout currently, I’m going to list what SAAB says it has developed and what the swedes has disclosed as being trained up and systems operational.
agm 65 whole series rb75 swedish callsign RB stands for “Robot” sweden has insured the gripen can fire all versions, but has only purchased the tv versions, in limited supply. br75a’s were developed post purchase, the range has been increased to around 6 kms. another mainstay of many training loadouts seen on the gripen is the bofors rockets. pods of six and the gripen has been seen carrying four at once. the bk90 mlojnir is similar to a JSOW. the mainstay of the gripen is the ansti ship rbs15f anti ship 15 mile range over the horizon, flies low profile then pops up in autonomous search much like a harpoon around a pre designated INS point. amraam ability up to four stand off ps05 standard doppler (so around 60 mile detection) TWS can track 4 and maintain bugs on 10 in the current gripen variant. it has all the standard paveway intervals, 500 1000, 2000. the iris T is on all versions as of today. it has enternal ECM but it is pretty sub par, most gripens on a lo lo lo or a sead or strike mission would be fitted with the ericcson ecm pod on the centerline.
something to take into account, pilots of gripens wear a one of a kind interfaced g suit that has multiple layers and is full body, and has been proven to reduce most g force loads felt by the pilot by almost 65%, meaning 9 gs feels more like 5. That should be taken into account for the redout and blackout rates when you fly the gripen. i’ve been reading about this system for the last 2 hours. This jet is really intriguing, the SAAB minds did something special here. They are really impressive.
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the variant of the engine used is not just a single output hornet engine, it was re-engineered from the floor up to give more stability and more thrust in a single engine compact airframe, which included shortening it, and taking weight off, among other things.
…sort of. The base engine was/is similar to the Hornet’s F404 “EPE” and a bit hopped up from there…maybe. Actually, it was developed from the engine that was supposed to go into the F-20 (which I still have a nice “F-5G” color glossy brochure for around…someplace). As was the EPE, if I recall…I forget. It was a very long time ago in another lifetime, when I was working for GE…I don’t think they shortened it any, but they did turn up the wick. But I do remember being shocked when they killed the F-20 for engine export then went and let GE license out the derivative for Gripen.
Here’s some really great Gripen renders to scroll through…including the bottom side -
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if anyone has the skill, I can name the function and closest “good enough” function for everything in this bad boy. I have actual saab diagrams for the sitck and the cockpit functions available to me.
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…sort of. The base engine was/is similar to the Hornet’s F404 “EPE” and a bit hopped up from there…maybe. Actually, it was developed from the engine that was supposed to go into the F-20 (which I still have a nice “F-5G” color glossy brochure for around…someplace). As was the EPE, if I recall…I forget. It was a very long time ago in another lifetime, when I was working for GE…I don’t think they shortened it any, but they did turn up the wick. But I do remember being shocked when they killed the F-20 for engine export then went and let GE license out the derivative for Gripen.
Here’s some really great Gripen renders to scroll through…including the bottom side -
i’ll say this stevie, I can tell there are certain things and philosophies we differ in, there is one that we don’t, it’s that god awful embargo…while I understand it was a necessary evil, it killed more than just that, it killed communication, we have three of the same aircraft and a bunch of things in the wild that shouldn’t be, a bunch of things that aren’t that should because of it. the f-20 lives on in the places it was cannibalized. That was truly the end of the real military reform movement, the real end.
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they took about 7 inches of the length, but this ends up being the modular assembly, its more important that these parts weigh less. the way the intake and fuel pump are gated is the biggest difference in the actual manufacturing of the engine, in performance terms the biggest difference is that this engine was short geared in a sense for a light weight fighter not a big maritime lady of the navy and it’s performance at low altitudes to fit the requirement of the contract was the biggest area of tuning from the literature I’ve digested.
I mean guys listen, the empty hornet weighs 23,000 lbs, I don’t know if you realize that a loaded gripen on average weighs 17000lbs with two tanks.