Viper without drag?

[marcoacv]

This week I flew several hours with the Viper and noticed that it got a lot faster and faster. This includes it loaded with two tanks and six 120s. I mean it doesn’t stop accelerating, now it’s faster than the F15 in the same condition. I believe that this condition could be revised. Since in all technical sheets the F15 is superior in speed compared to the viper. Thank you.

[dundun92]

Have you compared this to the actual performance charts for the F-16, like in the HAF supplement as an example?

[SandMartin]

Have you compared this to the actual performance charts for the F-16, like in the HAF supplement as an example?

 

DCS F-16 have 1000knots (~1800kmh) at sea level. This does not need to be compared with charts to understand that this is crap.

Edited July 20, 2020 by SandMartin

[TLTeo]

DCS F-16 have 1000knots (~1800kmh) at sea level. This does not need to be compared with charts to understand that this is crap.

 

 

Post a track then

[Quid]

This week I flew several hours with the Viper and noticed that it got a lot faster and faster. This includes it loaded with two tanks and six 120s. I mean it doesn’t stop accelerating, now it’s faster than the F15 in the same condition. I believe that this condition could be revised. Since in all technical sheets the F15 is superior in speed compared to the viper. Thank you.

 

 

I just tested this. The F-15C with 2x wing tanks, 4x AIM-9x and 4x AIM-120s gets to 1.87M/1075KTAS/597KIAS at 35,000ft. The F-16C with 2x wing tanks, 6x AIM-120 gets to 1.55M/984KTAS/498KIAS at 35,000 feet. So, the F-15C is faster at altitude. Something I will say is that the F-16 reached its speed faster than the F-15, so it might accelerate more quickly, but it doesn't achieve as high a maximum speed.

 

 

DCS F-16 have 1000knots (~1800kmh) at sea level. This does not need to be compared with charts to understand that this is crap.

 

 

The F-16 doesn't go 1000 knots on the deck. I ran three sets of tests, one clean (wingtip rails only), one with 2x wing tanks and 6x AIM-120Cs, and one with 2x wing tanks, 2x AIM-9X, 2x AIM-120C, 6x Snakeye and a TPOD. 100% fuel was taken with full tanks in the tank configurations due to the need to reach VMax. In the clean config, by the time I was sustaining VMax, I was down to about 2500lbs. Velocities were taken at about 100ft -

 

Clean VMax: 1.38M/920KTAS/908KIAS (note: the numbers fluctuate on Tacview, the very highest reading was 1.39/921KTAS before dropping to 1.37/909KTAS)

AMRAAM/Tank VMax: 1.05M/696KTAS/690KIAS

Bombs etc. VMax: 0.97M/643KTAS/640KIAS

 

Just to see how well the plane would do at altitude, I flew with the bomb/missile loadout at 31,000 feet:

 

VMax: 0.99M/582KTAS/351KIAS.

 

So, with that loadout, it couldn't even break Mach 1 at above 30,000 feet.

 

 

With respect to clean performance, is that faster than what the jet is rated for? Yes. Could it physically fly that fast? Not sure, but the 800KIAS VMax was a safety/engine limit, not the physical limit of the jet. I cannot speak with any expertise as to what happens when you overspeed the jet that far, or if that's a realistic number. I do know a pair of F-14As hit ~1.4M on the deck, well above the 780KIAS/<1.2M limit with Sidewinder rails installed, so it might not be that far off, but that's just anecdotal.

[SandMartin]

 

 

With respect to clean performance, is that faster than what the jet is rated for? Yes. Could it physically fly that fast? Not sure, but the 800KIAS VMax was a safety/engine limit, not the physical limit of the jet. I cannot speak with any expertise as to what happens when you overspeed the jet that far, or if that's a realistic number. I do know a pair of F-14As hit ~1.4M on the deck, well above the 780KIAS/<1.2M limit with Sidewinder rails installed, so it might not be that far off, but that's just anecdotal.

 

 

Yes, but when in the same simulator the F-15 and MiG-29 give 800 knots at sea level but the F-16 gives 920 does it not seem to you nonsense?

 

You can also compare acceleration at speeds above 1M at f16 and mig29/f15.

 

Aren't you worried that these aircrafts are meet online?

Edited July 21, 2020 by SandMartin

[mastersetter]

Was it in Dan Hamptons book, where he says the viper is limited due to the bubble canopy. At high air speeds it was melting and deforming, i cant remember the speed exactly, around 600 knots and above..?

[bies]

IRL down low F-16, especially Big Mouth GE Engine, is faster than any Eagle variant. It's due to the drag in very thick air and cambered leading edge of F-15's wing, kind of permanently inclined at a small angle leading edge flaps. Their drag at higher altitude (and AoA) is irrelevant but at very low alt they are punnishing. Since F-15 was design to operate at medium to high altitude lighter stiffer wing without leading edge flap but permanent camber had been selected.

 

 

 

 

The wing root is a 6 percent thick symmetric airfoil. The wing decreases in thickness towards the tip, which is a 3 percent highly cambered airfoil. The F-15 wing has conical camber outboard of he 20 percent semi-span location.

 

Up high fighter variants F-15 A and C are faster than F-16. Especially when non reguleted air intake of F-16 became inefficient, contrary to F-15's regulated intakes.

 

https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19890009868.pdf

Edited July 21, 2020 by bies

[GGTharos]

With respect to clean performance, is that faster than what the jet is rated for? Yes. Could it physically fly that fast? Not sure, but the 800KIAS VMax was a safety/engine limit, not the physical limit of the jet. I cannot speak with any expertise as to what happens when you overspeed the jet that far,

 

Your vertical stab might disintegrate (or any other part of the aircraft), causing an unrecoverable high-speed yaw moment which results in not being good for your health.

 

The airspeed limitations are not random and cannot guarantee structural integrity when passing them. Yes, you probably have an engineer's margin above those speeds but I suspect it won't be quite as high as in other things.

[Dee-Jay]

F-16 airspeed limitation is an engine limitation. Not an air-frame limitation.

[Hummingbird]

Was it in Dan Hamptons book, where he says the viper is limited due to the bubble canopy. At high air speeds it was melting and deforming, i cant remember the speed exactly, around 600 knots and above..?

 

I read the same a long time ago, and heard similar about the F35, i.e. canopy being limiting factor. No idea wether it's true or not on operational jets. I tend to think it's more about shockwave formations around the air intake(s).

[cofcorpse]

DCS F-16 have 1000knots (~1800kmh) at sea level. This does not need to be compared with charts to understand that this is crap.

 

Could you provide a track? I tried at normal conditions and didn't managed to achieve such speed.

[kingsnake11]

Just because you may have a lot of excess power, doesn't mean that you can use it simply to see how fast you're going without consequences. All aircraft have redline markings on the VI. It's 800Iknts for the 16 in DCS and it was the same for the CF-104G. You could go faster at really low level in the 104 but you would start having structural heat problems and likely cause yourself real problems. Unlike the F-16, the 104 wasn't thrust limited at high mach. At M1.2 and high altitude you could really feel the acceleration when you pushed into full AB. Even in a clean f-16 in DCS, I can barely get it past the Mach at very low altitudes.

 

The other limiting factor at high speed in real life is that you would run out of fuel real quick. Doing some ballpark math with an example; While a mig 29 could possibly get to 800 Iknots at 300 feet AGL he wouldn't be able to sustain it for long. He would be burning around 90 lbs of fuel for each nautical mile of performance(45lbs per engine)... with an internal load ( tanks would just add a lot of drag and weight so that the max speed couldn't be reached) of around 8000 lbs or so of gas, that would translate to a distance of 90 NM before running out of gas.. at 800knts it would take you 90/800 x 60 or roughly 7 minutes to run out of gas at that speed.... so just because it says you can do it on the Airspeed Indicator, doesn't mean you can actually do it in real life without dire consequences. When they talk about max airspeed for any aircraft..wow it can do mach 2.2!... what's left out is that it may do that only at altitude and they always leave out how long.

 

You can achieve max speed in a dive and then zoom or stay low...but the realities of fuel burn are still there. As an aside, if you ever thought of owning your own Mig-29, it would cost you probably $2K in fuel at todays prices for each showy full afterburner takeoff.

[Quid]

Yes, but when in the same simulator the F-15 and MiG-29 give 800 knots at sea level but the F-16 gives 920 does it not seem to you nonsense?

 

Not necessarily. On the deck, thrust-to-drag is more significant than thrust-to-weight for maximum speed. An F-111 is rated for the same speed on the deck as the F-15C in spite of its worse T/W ratio. A clean F-16 is a slick little bastard and it wouldn't surprise me if it was capable of getting as fast as it does in-game on the deck. What I will say is that doing so without any repercussions is where there is an argument. While looking into this further, I ran into some data at F-16.net, including an F-16A which was lost during an eggregious overspeed (1.5M at 2500ft - the pilot was diving to hit that high a speed) that caused the engine to warp and explode. The accident was on 12 February 1986/F-16A 78-0055, the pilot was lost after ejecting - further fidelity about the engine explosion was in the forums.

 

I think, if anything, the aircraft might physically be able to reach a speed like that, but what is nonsense about it is that the plane suffers no ill effect as a result. If it can be modeled, engine damage, airframe damage, or both as a result of overspeeding would be ideal. Just because a plane can overspeed to 1.38M on the deck does not mean it should, or that it won't come apart underneath you if you're dumb enough to push it that hard.

 

 

You can also compare acceleration at speeds above 1M at f16 and mig29/f15.

 

 

I'm not sure why this would be an issue. The F-16C with the big mouth and 110 engine ought to accelerate very quickly assuming it has a light/clean loadout.

 

 

 

Aren't you worried that these aircrafts are meet online?

 

 

Not at all, and why should you be? If one jet is faster than another on the deck, then it is an advantage to that jet. Should an F-5 keep up with an AJS-37? No. That's not unfair, that's a realistic performance difference between the two. The playing field is uneven because it is. But, like I said above, being able to do so without any repercussions is what generates the disparity in my mind.

[Syndrome]

The F-16 with bags on at sea level with a full tank isn't even breaking 599 knots. After dumping stores a few patches back I would get to 700+. Now I'm only hitting 639. I then tried having a clean wing, no pylons, and 1% infinite fuel. Starting at 650 knots, it took 2 minutes to hit 900 knots, and couldn't break it.

 

What sim is the OP playing? Because it's not DCS. If anything the drag has increased.

[GGTharos]

You might be able to reach it from a dive.

[Dee-Jay]

You might be able to reach it from a dive.

 

Sure it is possible in dive. But airframe won't really suffer from overspeed (except maybe abnormal structural fatigue in long term) ... But engine (mainly compressor) will suffer.

[SandMartin]

Not necessarily. On the deck, thrust-to-drag is more significant than thrust-to-weight for maximum speed. An F-111 is rated for the same speed on the deck as the F-15C in spite of its worse T/W ratio. A clean F-16 is a slick little bastard and it wouldn't surprise me if it was capable of getting as fast as it does in-game on the deck. What I will say is that doing so without any repercussions is where there is an argument. While looking into this further, I ran into some data at F-16.net, including an F-16A which was lost during an eggregious overspeed (1.5M at 2500ft - the pilot was diving to hit that high a speed) that caused the engine to warp and explode. The accident was on 12 February 1986/F-16A 78-0055, the pilot was lost after ejecting - further fidelity about the engine explosion was in the forums.

 

I think, if anything, the aircraft might physically be able to reach a speed like that, but what is nonsense about it is that the plane suffers no ill effect as a result. If it can be modeled, engine damage, airframe damage, or both as a result of overspeeding would be ideal. Just because a plane can overspeed to 1.38M on the deck does not mean it should, or that it won't come apart underneath you if you're dumb enough to push it that hard.

 

 

 

 

 

I'm not sure why this would be an issue. The F-16C with the big mouth and 110 engine ought to accelerate very quickly assuming it has a light/clean loadout.

 

 

 

 

 

 

Not at all, and why should you be? If one jet is faster than another on the deck, then it is an advantage to that jet. Should an F-5 keep up with an AJS-37? No. That's not unfair, that's a realistic performance difference between the two. The playing field is uneven because it is. But, like I said above, being able to do so without any repercussions is what generates the disparity in my mind.

 

Check this

https://forums.eagle.ru/showpost.php?p=702921&postcount=3

 

(google translate will be help)

 

"acceleration characteristics of F-16CJ and MiG-29 aircraft without external stores, in full afterburner, at an altitude of 1000 meters, in the range of 370 ... 1200 km / h are equal. (within the data reading error)"

Edited July 22, 2020 by SandMartin

[Quid]

Check this

https://forums.eagle.ru/showpost.php?p=702921&postcount=3

 

(google translate will be help)

 

"acceleration characteristics of F-16CJ and MiG-29 aircraft without external stores, in full afterburner, at an altitude of 1000 meters, in the range of 370 ... 1200 km / h are equal. (within the data reading error)"

 

 

That's the wrong motor (PW-229, not the GE-129). If you have those charts, check them yourself, but the -129 is faster than the -229. If the -229 powered F-16CJ accelerates roughly the same as the MiG-29, then the DCS F-16CJ, which has the -129 motor in it, correctly out-accelerates the MiG-29 at the altitudes highlighted in that post.