Cruise/supercruise aircraft comparison

[some1]

Over the weekend I did a little speed test in DCS with various aircraft, measuring their highest top "cruise" speed. Instead of going full throttle and waiting for the fuel or map to run out, I tried to find the max continous setting in the manuals, or just backed the throttle a bit. It's not a very scientific test, and of course different airframes can have different optimal altitudes and power settings than I used, but I just wanted to test them in the same conditions and "sort them" in my head.

 

All tests were done with take off with 60% of fuel, climb to altitude and then accelerate. TAS is of course True Air Speed :)

 

For subsonic aircraft the test altitude was 24000 feet and the results are as follows:

 

• Spitfire Mk XI 325 TAS (12lb 2850RPM - max continuous power)
  
• FW-190D 345 TAS (1.42ata 3000RPM - max continuous power)
  
• P-51D 350 TAS (47" 2700RPM - max continuous power)
  
• Bf-109K 355 TAS (1.32ata 2400RPM - max continuous power)
  
• A-10C 355 TAS 0.58M (82% fan speed, slightly less than full throttle)
  
• L-39C 390 TAS 0.64M (103%N1, max continuous)
  
• Su-25 475 TAS 0.78M (98%N1, slightly less than full throttle)
  
• Su-25T 475 TAS 0.78M (98%N1, slightly less than full throttle)
  
• C-101EB 515 TAS 0.84M (95%N1, ITT continuous limit)
  
• MiG-15 545 TAS 0.9M (11200RPM, nominal power according to manual)
  
• Hawk 550 TAS 0.88M (98%N1)
  
• AV-8B 550 TAS 0.91M (96%N1)
  
• F-86F 565 TAS 0.93M (96%N1 - end of green arc on the tach)
  

 

For the supersonic aircraft I flew at 36000 feet and used full military power (no afterburner)

• AJS-37 can't maintain level flight without afterburner. Really?
  
• MiG-21 545 TAS 0.94M aprox., instruments very unreliable showed that I was going supersonic, lol
  
• M-2000C 550 TAS 0.96M
  
• MiG-29A 560 TAS 0.97M
  
• F-5E 570 TAS 0.99M
  
• Su-27 585 TAS 1.02M
  
• F-15C 605 TAS 1.07M
  
• F/A-18C 665 TAS 1.15M
  

 

As you can see, in DCS without external payload three aicraft (not counting derivatives Su-33 and J-11) can supercruise and the clear winner of this race is the Hornet.

 

All tests done on the latest DCS 2.5.3.22176, default weather preset.

Edited October 1, 2018 by some1

[Mr_sukebe]

Interesting results, particularly how almost all of the jets are mid 500s without afterburners.

Have to say that I’m surprised that the Mig21 and F5 don’t have more of an advantage over say the harrier, which looks like it has aerodynamics of a brick.

[QuiGon]

Interesting test, thanmks for sharing :thumbup:

I find the results of the F-5E and the F/A-18C pretty suprising.

[some1]

Interesting results, particularly how almost all of the jets are mid 500s without afterburners.

Have to say that I’m surprised that the Mig21 and F5 don’t have more of an advantage over say the harrier, which looks like it has aerodynamics of a brick.

 

 

There's a reason why Sound Barrier is called, well, a barrier ;)

 

Harrier has better power to weight ratio than most of the airplanes, remember that it has to be able to take off vertically with some usable payload. Also the tests at different altitudes are not really comparable 1:1 because sound speed changes with altitude (or temperature, to be exact). So the max TAS attainable at 36000 feet may be a little lower because the aircraft hits the sound barrier sooner.

Edited October 1, 2018 by some1

[Lithion]

I knew I once supercruised the Hornet after dropping payload, is that a sim thing or actually plausible? :D

[Wissam24]

Given that the Hornet can't supercruise, this is a pretty bad oversight on ED's part and needs fixing.

[Xordus]

Most modern fighters are capable of doing just above Mach 1 at MIL thrust at medium altitude. Level flight envelope charts for both the F-16CJ Block 50 and F/A-18C EPE confirm it.

 

Mach 1.02 in level flight at MIL thrust can be expected with 2xAIM-9, 2xAIM-7 and 60 percent fuel (33,700 pounds GW) between FL250 and FL350 at ISA conditions.

 

 

 

 

That's not really considered supercruise though. Barely exceeding mach 1 with the lightest armament possible only demonstrates that most modern fighters AREN'T capable of supercruise. It's really only the very latest jets (of the last decade or so) and older interceptors that truly demonstrate supercruise capability.

 

 

It's a pretty amazing feat.

[Rlaxoxo]

60% fuel

 

Su-27 and 33 carry a huge load of internal fuel way more then Hornet and stuff.

 

Little unfair

[some1]

Yes of course, but the OP is the one confusing transonic for "supercruise". I'm just pointing out that "modern" fighters (from 40 years ago) are capable of putting up (nearly) the numbers the OP quotes.

 

There is no single definition of supercruise, not even for transonic range. So if you like, replace supercruise with "achieve level flight above the speed of sound without reheat" everywhere in the text, I prefer the shorter word.

 

60% fuel

 

Su-27 and 33 carry a huge load of internal fuel way more then Hornet and stuff.

 

Little unfair

 

Lol, and what would be "fair"?

 

If you read my first post, I actually acknowledged that these are probably suboptimal conditions for most airframes and that this is not very scientific test. Besides, Su-27 can take the most fuel but it also used the most fuel to get to the altitude. And whatever criteria you choose, it will still be the heaviest of the bunch.

[Nealius]

60% fuel

 

Su-27 and 33 carry a huge load of internal fuel way more then Hornet and stuff.

 

Little unfair

 

And all the aircraft have different engines, different thrust/weight ratios, different aerodynamics, etc. What's your point? If it's that there's no apples-to-apples comparison, well that's impossible to avoid when comparing different aircraft.

[Mars Exulte]

Yeah, none of that seems terribly out of place, as others commented barely breaking the barrier doesn't really count. The only one that strikes as a possible issue is the F-18. M1.15 seems a little high, but still within the realm of possibility.

[some1]

The biggest surprise for me is actually that Viggen can't even maintain level flight at this altitude.

It should have 70kN dry thrust, that's as much as MiG-21 has on afterburner. And it's lighter than the Hornet in the test.

[Quadg]

isn't the service ceiling of a su-25 23000ft?

[swatstar98]

isn't the service ceiling of a su-25 23000ft?

Yes, it is!

[some1]

If you refer to that wikipedia article, then better check the "article talk" page.

There's been a lot of controversy relating this topic since the downing of Malaysian 777. IIRC Russia claimed it was Ukrainian Su-25 that shot down the airliner, and suddenly the stats on the Wikipedia were adjusted to show that Su-25 could actually intercept the Boeing at cruise altitude. And then all hell broke loose.

 

But if you ask me, compared to other aircraft, 23000ft service ceiling for empty aircraft is way too low, just looking at the thrust-to-weight ratio and the conventional design. Unless the engines magically loose thrust at high alt.

[Mars Exulte]

Yeah, 1940s aircraft were flying 20k+, I'd be very surprised if a Frogfoot couldn't fly higher than that, there's no reason it couldn't. It's lighter and faster than an A-10 and IT has no problem flying that high.

 

About the Viggen, I don't know. The attack version we have is specifically optimised for treetop flight. It's possible the engine just loses thrust at higher altitude. Probable, even. All supersonic aircraft are not created equal or designed for tge same flight regime. Case in point, the wings and canards are oversized and draggy compared to say a Eurofighter or even Su-35, which hurts it at high altitude at speed, but provides lift for hard maneuvering at low levels.

Edited October 1, 2018 by zhukov032186

[Quadg]

don't bring up that incident. we will become casualties of maskirovka if we discuss it:)

 

safer to use a number from 2004? no?

and janes is a good source.

 

I think the issue is conventional air intake not providing the engine enough air at high altitude.

because its optimised for the opposite. it does not need complex moving ones. like on migs.

[Bogey Jammer]

The F/A-18 ? that fast ?? :shocking:

What does it sacrifice to get so much power available ?

[some1]

About the Viggen, I don't know. The attack version we have is specifically optimised for treetop flight. It's possible the engine just loses thrust at higher altitude. Probable, even. All supersonic aircraft are not created equal or designed for tge same flight regime. Case in point, the wings and canards are oversized and draggy compared to say a Eurofighter or even Su-35, which hurts it at high altitude at speed, but provides lift for hard maneuvering at low levels.

 

Well, I looked in the Viggen subforum and the aircraft seems to have some long standing bugs with high altitude performance:

https://forums.eagle.ru/showthread.php?t=199853

https://forums.eagle.ru/showthread.php?t=181927

 

It was never a a stellar performer, but it shouldn't be that bad. All in all, they made an interceptor out of it without changing aerodynamics other than extending the fuselage to make space for slightly more powerful engine.

 

I think the issue is conventional air intake not providing the engine enough air at high altitude.

because its optimised for the opposite. it does not need complex moving ones. like on migs.

 

Nah, the moving intakes are needed for very high speeds around Mach 2, to block the air and slow it down before it hits the engine. Even supersonic aircraft like F-16 or Hornet don't have those as they are not required to go Mach 2+.

Edited October 1, 2018 by some1

[NineLine]

Based on SME feedback, it is correct that the Hornet is capable of this. Even with a centerline tank and wingtip AIM-9s.

 

Even the dev team thought it was a bug at first until thoroughly researched, and it was found to be correct. Another testament to the ED PFM.

Edited October 1, 2018 by NineLine

[Quadg]

Nah, the moving intakes are needed for very high speeds around Mach 2, to block the air and slow it down before it hits the engine. Even supersonic aircraft like F-16 or Hornet don't have those as they are not required to go Mach 2+.

 

the mig 15 is subsonic and has a moving nose cone air intake.

for a higher service ceiling.

[probad]

the mig 15 is subsonic and has a moving nose cone air intake.

dog what are you smoking???

[NineLine]

A testimate to a PFM that is wrong, according to the -210 performance manual. But whatever.

 

I'd post the level flight envelope chart, but you changed to rules to disallow it.

 

We have that, plus men that have many hours in the real thing. I think we are good, thanks.

[mkellytx]

Given that the Hornet can't supercruise, this is a pretty bad oversight on ED's part and needs fixing.

 

Hardly, a clean C with the up rated F404's is well known to go supersonic clean. Back in the day, Fighter Tactics Academy and Rec.Aviation.Military talked about this extensively, including first person accounts of it. Since it was still transonic and not the 1.5M of the Raptor, RAM referred to it as "spif-cruising". Block 50/52's clean are also able to cruise greater than Mach clean.

[Mars Exulte]

the mig 15 is subsonic and has a moving nose cone air intake.

for a higher service ceiling.

 

The MiG-15 does not have a nose cone, much less a movable one. Easily verified by looking at ANY photo, you will notice a distinct lack of conelike structures anywhere on the aircraft, especially the nose. It has a large gaping intake with a divider to flow air around the cockpit and back to the engine.

 

The MiG-21 has a moving nose/shock cone, it is also supersonic. The cone has nothing to do with 'service ceiling'. It serves tge same purpose as variable intakes on any other aircraft.