Good Climb Rate

[The AMRAAMer]

After take off when you're heading to the AO, what's a good, consistent, climb rate? Is there one value for all aircraft? If not, what's a good climb rate for the F15 and other fighters like it?

[draconus]

For F-15C: what nighthawk2174 says below - it's from the -1. For other aircraft it's different.

Edited May 13, 2019 by draconus

[nighthawk2174]

"If at MIL power, climb at 350 knots to 0.90 Mach, then maintain 0.90 Mach. If at MAX power, climb at 350 knots to 0.95 Mach. If Mach increases above 0.95 at 40° pitch attitude, hold 40° and allow the Mach to increase (Mach will rise only slightly before returning to 0.95). "

[The AMRAAMer]

"If at MIL power, climb at 350 knots to 0.90 Mach, then maintain 0.90 Mach. If at MAX power, climb at 350 knots to 0.95 Mach. If Mach increases above 0.95 at 40° pitch attitude, hold 40° and allow the Mach to increase (Mach will rise only slightly before returning to 0.95). "

 

Where can I find these values for other aircraft? If you have them on hand for the A10, F14 and F16 can you provide? Thank you

[Kazansky222]

"If at MIL power, climb at 350 knots to 0.90 Mach, then maintain 0.90 Mach. If at MAX power, climb at 350 knots to 0.95 Mach. If Mach increases above 0.95 at 40° pitch attitude, hold 40° and allow the Mach to increase (Mach will rise only slightly before returning to 0.95). "

 

Did you pull those from Mig-29 Manual? Is that Max rate or Cruise climb?

[bbrz]

Is that Max rate or Cruise climb?

Only if you are using less than MIL/MAX power it's a 'cruise' climb.

Since jet engines are using a lot of fuel at lower altitude you usually climb with max climb power in all jets.

The above speeds are for the F-15C.

 

350 is surprisingly low for a MAX power climb since e.g. the optimum climb speed for the F-5E in clean config is 590kts / M0.93.

Edited June 12, 2019 by bbrz

[GGTharos]

350Kts is the optimum climb speed for minimizing fuel-to-altitude IIRC.

Yours is minimizing time-to-altitude and is used in difference circumstances.

 

350 is surprisingly low for a MAX power climb since e.g. the optimum climb speed for the F-5E in clean config is 590kts / M0.93.

Edited June 12, 2019 by GGTharos

[bbrz]

350Kts is the optimum climb speed for minimizing fuel-to-altitude IIRC.

Yours is minimizing time-to-altitude and is used in difference circumstances.

Hm, I don't think so. The F-15 and the F-5E both have a single fixed climb speed schedule for MAX power, there are no other speeds/climb schedules available for different circumstances.

 

E.g. the F-4E and the Tornado are also much higher IAS, 595kias/M0.90.

The F-105 even needs 615/0.93 and the F104 a slightly lower 610/0.925.

 

What is surprising (for me) that the F-14A is a real Turkey with a climb Mach Number of 0.70 even in the clean case. That's a lot slower than every civil airliner!

[sLYFa]

there are no other speeds/climb schedules available for different circumstances.

 

I don't know about the F-15 specifically, but generally, there are always two climb schedules: Best rate of climb and best fuel economy. Military airplanes often have a third climb schedule for AB best rate of climb.

 

E.g. the F-4E and the Tornado are also much higher IAS, 595kias/M0.90.

The F-105 even needs 615/0.93 and the F104 a slightly lower 610/0.925.

That M 0.7 you quoted is the best fuel economy rate of climb for the Tomcat, while the values for the F-4/Tornado are likely for AB climb. There is also an AB max rate of climb schedule for the F-14 which also prescribes M 0.9.

 

What is surprising (for me) that the F-14A is a real Turkey with a climb Mach Number of 0.70 even in the clean case. That's a lot slower than every civil airliner!

No surprise at all. Unlike most other fighters, the Tomcat has a high aspect ratio and can climb more efficiently than other fighters. Hence its fuel conservation climb speed is about that of commercial airliners (A320 climbs at around M 0.7/0.8 once it gets high enough).

[bbrz]

I don't know about the F-15 specifically, but generally, there are always two climb schedules: Best rate of climb and best fuel economy. Military airplanes often have a third climb schedule for AB best rate of climb.

(A320 climbs at around M 0.7/0.8 once it gets high enough).

Can you point me to the additional climb schedules in the F-4, F-105 and Tornando flight manuals ? I didn't find any.

The (rather slow) A320 standard climb is .78 and with a high drag index the F-14 climbs at M.62, I could never fly that slow with a heavy 767!

 

I didn't find anything in the F-14A manual which mentions a 'best fuel economy rate of climb'. It simply 'climb speed schedule military power' which means max climb thrust and hence max ROC.

Couldn't find an AB climb schedule either in the manual.

Edited June 13, 2019 by bbrz

[sLYFa]

There is also a best roc schedule furhter down and an AB climb schedule in the mission planning section.

Edit: Apparently, the best roc section is only present in the -B manual. But from an aerodynamic point of view, there is always best roc climb and best fuel economy climb, no matter if its a cessna or a B747.

Edited June 13, 2019 by sLYFa

[bbrz]

.. there is always best roc climb and best fuel economy climb, no matter if its a cessna or a B747.

That's new to me. Especially on a jet which uses a lot more fuel at lower altitudes. So the max ROC results in the best fuel economy as well or am I wrong?

Not aware that there are different climb tables e.g. in a C152.

[sLYFa]

So the max ROC results in the best fuel economy as well or am I wrong?

Not aware that there are different climb tables e.g. in a C152.

 

Probably yes but not neccessarily. It depends on the indivdual aircraft. For the F-14, there appears to be some difference. I remember the Tu-154 also had two climb schedules, one for economy and one for fastest climb.

 

In GA aircraft, the tables often boil down to a single value.

There is also a max climb angle speed, but its probably not that relevant for fighters.

Edited June 13, 2019 by sLYFa

[bbrz]

There is also a max climb angle speed, but its probably not that relevant for fighters.

On many airliners, e.g. the DC-9 Vx and Vy are basically identical and hence Vx is not used. That's why there's on jets usually only a single optimum climb speed.

Again, for the F-14A, the F-15 etc. there's apparently also only one single optimum climb speed.

 

Since the Tu-154 isn't exactly a fuel efficient airplane I can imagine that there's a separate 'econ' climb ;)

Edited June 13, 2019 by bbrz

[Vatikus]

in mil jets manuals... military power climb is tabulated for fuel efficiency, while max AB climb is minimum time.

[bbrz]

in mil jets manuals... military power climb is tabulated for fuel efficiency, while max AB climb is minimum time.

Well that's obvious ;) The original discussion was, why the F-15 uses the same, rather low IAS for mil and AB climb, while there's usually a big difference for most other planes.

[GGTharos]

What you mean is that there are no other schedules that you have seen.

 

Hm, I don't think so. The F-15 and the F-5E both have a single fixed climb speed schedule for MAX power, there are no other speeds/climb schedules available for different circumstances.

[bbrz]

What you mean is that there are no other schedules that you have seen.

I doubt that any pilot would use speed schedules that aren't written in the -1 / flight manuals.

[GGTharos]

You mean you don't believe there are schedules that you haven't seen :)

 

The -1 gives you pretty much most of the basics. They're basics.

[bbrz]

You mean you don't believe there are schedules that you haven't seen :)

The -1 gives you pretty much most of the basics. They're basics.

This has nothing to do with what I believe. Most likely test pilots have done quite a few other climb tests, but I'm not aware of other 'secret' performance manuals e.g. F-15 pilots get?

Why would MCD and/or the USAF hide optimum performance data from their manuals, or not include them in the -1?

 

Thinking of it, since it's (now) Boeing in case of the F-15, it might be the same case as with MCAS. It's there but they are not going to tell you or mention it in the -1 ;)

Edited June 13, 2019 by bbrz

[GGTharos]

This has nothing to do with what I believe. Most likely test pilots have done quite a few other climb tests, but I'm not aware of other 'secret' performance manuals e.g. F-15 pilots get?

 

That's ok, I am. There's an entire volume of flight data that I'd love to get my hands on, but they're not just climb schedules. Others are profiles created by squadrons for specific purpose that you'll just not see published anywhere. If you want an example, you can reference the streak eagle profile design.

 

Why would MCD and/or the USAF hide optimum performance data from their manuals, or not include them in the -1?

 

Ask them. I mean, it's not like I can provide you with the answer to that particular question.

[bbrz]

Ask them. I mean, it's not like I can provide you with the answer to that particular question.

Ah, ok. I see....

[Vatikus]

Well that's obvious ;) The original discussion was, why the F-15 uses the same, rather low IAS for mil and AB climb, while there's usually a big difference for most other planes.

it is important to notice that 350 is until you intercept 0.95 mach then you fly mach number. That being said there are for sure (based on the existance for other planes) tactical manuals for specific climb programs which are not public.

[bbrz]

it is important to notice that 350 is until you intercept 0.95 mach then you fly mach number. That being said there are for sure (based on the existance for other planes) tactical manuals for specific climb programs which are not public.

The crossover altitude in this case is already FL330....

I don't think that there are specific climb programs, since there's only one optimum speed at which you can achieve the highest ROC. Flying a high performance jet isn't that complicated ;)

 

In case of the Streak Eagle I agree with specific climb programs, but that's a completely different case.

[Vatikus]

I don't think that there are specific climb programs, since there's only one optimum speed at which you can achieve the highest ROC. Flying a high performance jet isn't that complicated ;)

But they are and they are not a straight climb either... operationally you want to be at some desired speed at the time of the intercept thus programs involve accelerations in your climb profile. Also available Ps changes with G, and you need G to maneuver, which again influences how to climb for minimum time.

You can say that -1 manual have general profile (whatever it was desired) but you also have tactical minimum time climbs...