Jun 22, 2010

Aerosoft vs IRIS F-16 for FSX: Head-to-Head Fly Off

AEROSOFT VS. IRIS F-16 FOR FSX:  Head-to-Head Fly Off

Professional pilots, aviation enthusiasts, RC modelers and flight-simmers alike all have some form of admiration for the General Dynamics F-16 "Fighting Falcon" or as it's pilots nicknamed it, the "Viper".  Almost everyone drools over it's ultra-sleek fuselage shape and those familiar with it's performance remain in awe of it's uber-tight turning radius and it's unique and completely visually-obstruction-free bubble canopy, something never before seen in any aircraft prior to it's launch.

So it should be no surprise that the flight-sim community has been graced with no less than two premium F-16 add-ons for Microsoft Flight Simulator X (FSX as it's more commonly known), one from Aerosoft and yet another from IRIS Simulations.  At first blush the two models appear to be quite similar (other than the obvious single vs. tandem-seat configurations) but in fact the two birds differ quite a bit from each other in various ways, and this review will cover all that I've had time to test.


Aerosoft chose to model the single-seat version, that being the F-16 A, AM and C models from both the US and it's allies.  IRIS models the F-16 D two-seat version, again both US and allied countries being represented.  Both companies provide "clean" and load-out variants with external stores ranging from missiles, FLIR pods, externals tanks, bombs smoke generators (for the various demo teams) and of course accurate representations of the liveries from the various squadrons and teams that use the aircraft.  Below are some of my favorite livery schemes from both versions but not at all the complete list.  (see pics below)


Both Aerosoft and IRIS do a great job of accurately modeling the aircraft shape, size, panel and line locations and livery markings down to minute details.  However they both also make some not-so-obvious errors that should have been caught prior to product launch and below is the list of niggles:

-  The Aerosoft intake and exhaust internals are too bright (see pics below).  There's no way in the real world that you can see all the way back into the inlet and see the fan blades of the main compressor or, see into the back of the exhaust nozzle up to the rear turbine blades while looking from the outside.  You'd either need to have stuck your head inside these areas and let your eyes adjust to the light or, have used some very bright lights to light up what is otherwise a very dark place.  IRIS on the other hand got this right and both the inlet and exhaust areas "fade to black" as you look directly inside.  Interestingly IRIS made the same "too bright inside" error on their F-14 but obviously learned from this mistake prior to launching the F-16.

-  The Aerosoft landing gear leaves something to be desired as both the physical modeling and the rolling-wheel animations look far less polished than the IRIS which again, takes the lead on small-detail visuals.

-  The size of the exhaust nozzle or "turkey feathers" is too long on the IRIS; the Aerosoft size is just a tad too small.  Somewhere in between is the correct size - but Aerosoft's is closer to reality.

-  The animation of that same exhaust nozzle is another story entirely:  IRIS has correctly replicated the smooth and somewhat delayed motion of the nozzle during throttle operation, most especially during landing gear operation where the nozzle opens-up fully ONLY after the gear is extended.  By contrast the Aerosoft nozzle is directly tied to the throttle lever; move the throttle forward and back and the nozzle opening moves in direct proportion to the throttle position with zero delay.  Zip the throttle back and forth super-fast and the nozzle opens and closes with the same speed.  This is completely inaccurate as the hydraulic system in the real aircraft would not only not be able to keep pace but the engine management computer which regulates the nozzle opening would wait for the engine to either spool up or down before making a nozzle adjustment.  IRIS nailed this one properly whereas Aerosoft either ignored it completely or simply didn't understand how that system is setup on the real aircraft.

-  When airborne the rear flaps will lower in the Aerosoft when the airspeed drops below 200 knots; the IRIS will only drop flaps when you lower the gear or, select a manual flap override in the cockpit.  Since I'm not an F-16 pilot I'm not sure which is more realistic but considering IRIS has replicated systems more accurately I'll assume they got this portion correct.

-  There are 2 things that make the F-16 visually interesting in flight:  The long vapor-streaks that emanate from just in front of the wing strakes which are a signature characteristic of the F-16 that hug the side of the fuselage during high-G maneuvers and, the smoke trail coming from the engine exhaust during mid-to-high throttle settings.  Aerosoft did a superb job of replicating both of these external characteristics; IRIS didn't do either.  For IRIS to completely ignore the vapor-streaks considering how much attention was spent on systems is very disappointing especially since it's such a noticeable trait of the F-16.  I can't help but wonder if IRIS just never noticed, purposely ignored it or forgot and found out too late before making the release.  (Update:  After emailing the IRIS designer for their F-16 the way the a/c was created meant that vapor trails was something that had to be left-off for some reason relative to how the model was built).

-  External lighting is yet another mixed-bag:  While they both realistically replicate the single white strobe on the top the vertical stab and both flashing and steady fuselage lights the Aerosoft goes a step farther - in the wrong direction.  When you turn on the interior cockpit lights (which by the way also turns on the flood lights at the same time) it also activates an external "livery flood" light on the tail projected by two points on the upper empennage (tail section).  While it sounds incredulous that a fighter would have flood lights on it's tail they actually do exist on the F-16 - but only on certain models, not all of them, and the Aerosoft doesn't allow for them NOT to be turned on when the interior lights are also on.  There are also smaller white lights on the top of the fuselage that Aerosoft modeled which get turned on as well but these aren't as pointless as the livery lights.  IRIS on the other hand didn't replicate the livery flood lights nor the added white marker lights but did do everything else including both upper and lower landing/taxi lights which unlike the Aerosoft are switchable and properly modeled.

-  External coloring is also a mixed bag.  Some variants of the Aerosoft seem to have missed color accuracy whereas the IRIS seems closer to real-world.  This is especially noticeable in the "Thunderbirds" livery included in both packages, IRIS getting the nudge for more color accuracy.

-  One last external visual niggle on the IRIS:  When the aircraft is on the ground and completely still, even powered off, it will wobble from side to side like a drunken sailor when you move the stick side-to-side.  I've seen freeware aircraft do this but for a premium payware plane to do this is totally unacceptable.  This same wobbly-kneed behavior also makes for less than straight rollouts on touchdown and uneasy ground handling.  The Aerosoft doesn't exhibit this wobbly-kneed bug.


These two areas are something where the Aerosoft and IRIS part company quite distinctly when it comes to accuracy:

The Aerosoft provides a very simplified cockpit with not-so-realistic looking gauges and switches and not many of the real aircraft system are replicated, most especially when it comes to lighting controls as mentioned above.  The HUD shape and display information isn't always easy to read either.  Cockpit internal lighting is horrible as there's no way to only light up internal panels alone, the damned flood lights are directly tied to the internal switches and no way to separate their operation.

IRIS on the other hand has in fact replicated every system that FSX limitations would allow.  On top of that gauges and switches are much more realistic both in their appearance and operation.  Unlike the Aerosoft, IRIS offers near-full control over lighting, both internal and external, engine and flap operations, radios and even weapons controls.  The overall appearance of the entire cockpit is amazingly life-like making gauge markings very easy to read, especially the HUD displays which in comparison to the Aerosoft are amazingly crisp and readable.  The internal lights operate exactly as they should, with gauge lights and flood lighting being separate allowing for much easier reading during night ops or daylight when shadows cover switch groups.

The fuel gauge is completely useless in the Aerosoft whereas the IRIS actually shows fuel on-board and as you burn it off it winds down accordingly.

Overall Aerosoft's modeling of systems is poor and comparatively lazy and in fact they mention the supposed limitations in their documentation, saying that what wasn't simulated wasn't possible to do in FSX.  Obviously that's completely wrong since IRIS did an amazing job of systems simulation.


You'd expect these two F-16 offerings would fly similarly but they don't and in fact behave very differently when compared head-to-head.

IRIS has supposedly modeled the "fly-by-wire" system in the F-16 to a higher degree than the Aerosoft however they did create one big bug which is the rudder.  In-flight with gear-up you have zero control over rudder inputs and the plane flies as if you have "autorudder" turned on in FSX, even if you don't.  That means that crisp aileron-type rolls are impossible, making barrel-rolls how the plane actually performs.  Even slow, smooth movements in either direction, left or right of the stick will engage rudder-type movement from the aircraft creating far too much yaw.  You only have rudder authority when the gear is down.  That can't be how the real aircraft performs and I'm inclined to think it has something to do with the "wobbly-knee" bug mentioned earlier.

The Aerosoft's rudder actuation is more realistic; if you push the stick to the side for an aileron roll that's what you get.  If you kick in hard rudder the plane will yaw deep and roll, just as you would expect it to. 

On the other hand, the IRIS tends to keep it's nose where you pointed it which would indicate that indeed their fly-by-wire simulation is more accurate.  The Aerosoft by contrast is a bit more lazy and while in a turn will actually drop the wing further during the turn forcing you to make a reverse-aileron correction to keep the bank angle where you had it originally.

The IRIS accelerates and decelerates far too fast to be realistic; you can punch up 400 knots and bleed it off in a heartbeat especially in a clean configuration much faster than the Aerosoft.  If the real F-16 performed as well as the IRIS neither the F-18 nor the F-22 could catch up to it!  I'm inclined to think that the Aerosoft is closer to real-world in this category as throttle-to-speed ramps take a great deal longer.

Both aircraft seem to replicate takeoff and landing speeds accurately; fully loaded with external stores you won't rotate until about 220 knots and an ideal landing speed with the same configuration and load-out is around 170 knots.  Much less for both with a clean configuration and bingo fuel.

The IRIS takes systems replication to a whole new sense of realism in this aircraft; you need to pay attention to the FTIT (fan turbine inlet temp) gauge in the cockpit.  If you redline this parameter too long (and your warning gauge will alert you to an ENG problem) you'll permanently damage the engine and it will die without the ability to re-start it - until you reset your FSX flight.  That means you'll be looking for an airport to hopefully make a dead-stick landing!  You can easily redline the FTIT by flying at low altitudes at airspeeds above 700 knots with power at or above 100% (afterburners don't need to be engaged).  At higher altitudes as the outside air temp drops - above 10,000ft - you won't have to worry about this.  But if you get a full head of steam way up top and make a nosedive whilst in the middle of some aggressive ACM you'd better pay attention to the FTIT needle and keep it out of the red otherwise you're dead meat.


Internally both the Aerosoft and IRIS are near identical; startup-and shutdown sounds are similar however the roll-up wind noise against the bubble canopy ramps up and down much more noticeably in the IRIS.  The Aerosoft is using some of the FSX default sounds for the front intake, one of those sounds being affiliated with the Learjet, and sometimes it can be annoying to hear an engine whine you know doesn't belong to the F-16.

The only niggle with Aerosoft internal sounds is that during rollout or high-speed taxi the landing gear makes rattles and squeaks, like an old shopping cart.  I can guarantee you that if the real aircraft made sounds like that the maintenance crews would pull it out of service and have the landing gear overhauled, so there's no way that's an accurate reproduction of gear noise.  The IRIS has a low-frequency grumble that you'd expect to hear from ground rolls.

Externally however it's a completely different story and yet another area these two models part company.  The IRIS uses a synthesized sound pack for engine sounds in which you can clearly hear the points where the sound file loops on itself.  While different from the default F-18 sound pack it's not very realistic sounding at all and is one of the most annoying features of the IRIS sound.  Especially when the afterburners kick-in (or engine re-heat if you're British) the IRIS external engine noise kicks in a whole new level of synthesized screech.  What's interesting is that in the real aircraft there's almost no perceptible change in engine frequency or amplitude from full military power and full AB, so IRIS got this one wrong.

The Aerosoft by contrast uses a sampled sound pack taken from the actual aircraft (or so their marketing says) and all engine noises are very realistic.  In fact, the first time I heard the engine from the rear as you ramp up to full power from idle, boy howdy... I got goosebumps!  It sounds as if the air molecules are being ripped and torn apart as the engine bellows out it's powerful sound-print as only a military jet engine can do.  Oh yeah... firewall the throttle on this baby you're belching out a warning the world can hear!

At some point I'll find a way to post samples of those sound clips here on the Blogger platform but for now you'll have to take my word for it:  The Aerosoft external sound pack will give you goosebumps!


This one also is markedly different.  The Aerosoft with a 3D cockpit turned on takes a heavy toll on frame rates.  The IRIS doesn't affect frame-rates any more than a default FSX aircraft which is surprising considering how many systems are replicated and how gorgeous the cockpit interior is.


The detail in pilot is quite different in these two models:  The Aerosoft pilot is constantly moving his head around from side to side and, when you kick in the rudder his head follows rudder movement; this may also explain why their model takes a hit on frame rates for this constant animation. The IRIS keeps the flight crew static (non-moving) however they change their head position from time to time randomly and do not follow rudder movements.  I've not figured out how or what controls their random head positions and IRIS has not responded to an email about this.

CONCLUSION:  A TIE (Almost) !!

Overall the IRIS is modeled more individual items correctly, and especially with a/c systems they really outdid themselves when compared to the lazy-man's version of systems in the Aerosoft.  BUT, IRIS missed the mark on some very key and highly noticeable traits of the F-16 both in visuals and handling in which Aerosoft gave a virtual smack-down to it's rival.  And because both these companies missed the mark enough times they both tend to equal each other out in overall standing head-to-head.  I'd give both of these models a solid 8 out of 10, for different reasons.

However, if you were going to somehow combine the best of both and make the ultimate, most accurate F-16 simulation for FSX here's what it would look like:

External visuals:  Take your pick; they both did superb jobs of fine details
External Animations (vapor trails, smoke):  Aerosoft
Internal Sounds:  IRIS.
External Sounds:  Aerosoft  (oooh, yeah!)
Exhaust Nozzle Animation:  IRIS
Exhaust Nozzle visual size:  Aerosoft
Flight Model:  IRIS (assuming fixing the rudder issue)
Aircraft Systems:  IRIS
Lighting:  IRIS
Ground Handling:  Aerosoft
Frame Rates:  IRIS

Truth is, I end up flying both of these models about the same amount.  I get annoyed with hearing the grossly inaccurate external sounds or dealing with the lack of rudder control in the IRIS and I'll switch to the Aerosoft.  But the Aerosoft will lose favor when I take a hit on frame-rates in multiplayer or when the external lighting at night makes me cray or that the less than accurate cockpit lighting just feels too goofy.  Neither one is perfect and they both exhibit traits that show it.

One last thought about these two differences:  Aerosoft seems to be on an update path for their model; version 1.21 was tested.  IRIS on the other hand does not seem to offer updates for their models as I've never seen an update posted anywhere on their site (their support directs you to their forum which is loosely put together at best).  So while Aerosoft might fix the bugs in their model in the future it seems once IRIS releases a model that's it, they're off onto something else and consider their releases "final".  Too bad since they're closer to a perfect model than Aerosoft in certain key areas.

On the whole you can't go wrong with either of these models.  I would suggest however that if you go with the Aerosoft that you turn off "3D cockpit" in FSX preferences as this will help greatly in multiplayer scenarios.

Maybe someday a very creative and knowledgable code-monkey will find a way to merge these two aircraft - or at least learn from their mistakes - and produce the worlds perfect F-16 for FSX.  I'd pay money for that!

And if you ever want to be my wingman, just look me up on FSX multiplayer.  You'll most likely see me logged in as either "lenzdude" or "Viper602".

Tailwinds to all.

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