F-35 unrestricted climb

[F-22Raptor]

Wow!

I thought F-35's can't climb?

 

[KAL-EL]

Forget about just not being able to climb. I thought the F-35 was practically a piece of junk in general.

Well, that's what I've read on PDF anyway. So I assumed it was true in the real world too

 

[maximuswarrior]

LOL if only climbing was enough to be certified a good fighter...

 

[CriticalThought]

Wow!

I thought F-35's can't climb?

Instead of trying to hide an average climb rate behind clouds, take a look at what an excellent climb rate looks like:

Watch from 7:35

 

[Penguin]

Rate of climb: Measured at sea level, rate of climb indicates how quickly an aircraft can reach a given altitude.

(Max) Rate of climb:
F-35A: Classified
Typhoon: 62,000ft/min = 315 m/s
Rafale: 60,000ft/min = 305 m/s
JAS-39E/F: 50,000ft/min = 254 m/s
F/A-1E/F/G: 44,882ft/min =228 m/s
http://gripen4canada.blogspot.nl/p/how-the.html

F-16: 50,000 ft/min = 254 m/s
https://en.wikipedia.org/wiki/Gener...ng_Falcon#Specifications_.28F-16C_Block_50.29

JF-17: 249 m/s
http://forum.keypublishing.com/show...he-2-spot-behind-Gripen&p=2033587#post2033587
JF-17: 175 m/s
https://tribune.com.pk/story/554668/countries-express-interest-in-pak-chinas-jf-17-thunder/

FC-1: 34,450 ft/min = 175 m/s
https://www.aircraftcompare.com/helicopter-airplane/Chengdu-FC-1-Fierce-Dragon/400

 

[CriticalThought]

Rate of climb: Measured at sea level, rate of climb indicates how quickly an aircraft can reach a given altitude.

(Max) Rate of climb:
F-35A: Classified
Typhoon: 62,000ft/min = 315 m/s
Rafale: 60,000ft/min = 305 m/s
JAS-39E/F: 50,000ft/min = 254 m/s
F/A-1E/F/G: 44,882ft/min =228 m/s
http://gripen4canada.blogspot.nl/p/how-the.html

F-16: 50,000 ft/min = 254 m/s
https://en.wikipedia.org/wiki/Gener...ng_Falcon#Specifications_.28F-16C_Block_50.29

FC-1: 34,450 ft/min = 175 m/s
https://www.aircraftcompare.com/helicopter-airplane/Chengdu-FC-1-Fierce-Dragon/400
JF-17: 175 m/s
https://tribune.com.pk/story/554668/countries-express-interest-in-pak-chinas-jf-17-thunder/
JF-17: 249 m/s
http://forum.keypublishing.com/show...he-2-spot-behind-Gripen&p=2033587#post2033587

None of these numbers is actually authentic as far as Thunder's climb rate is concerned. Using seat of pants calculation, assuming weight of 9100 kg, thrust of 98 kN, and ignoring air resistance, I compute Thunder's climb rate to be 281 ft/s.

Since,

F = m a

98000 N = 9100 a

=> a = 10.769 m/s^2

Net acceleration (ignoring air resistance) = 10.769 - 9.8 = 0.969 m/s^2

Starting from sea level (r = 0) and stationary condition (velocity is 0)

S = (1/2) a t^2

50000 ft = 15240 m

15240 = (1/2) 0.969 t^2

=> t = 177.33 s

50000 ft / 177.33 s = 281.95 ft/s

 

[Penguin]

None of these numbers is actually authentic as far as Thunder's climb rate is concerned. Using seat of pants calculation, assuming weight of 9100 kg, thrust of 98 kN, and ignoring air resistance, I compute Thunder's climb rate to be 281 ft/s.

Since,

F = m a

98000 N = 9100 a

=> a = 10.769 m/s^2

Net acceleration (ignoring air resistance) = 10.769 - 9.8 = 0.969 m/s^2

Starting from sea level (r = 0) and stationary condition (velocity is 0)

S = (1/2) a t^2

50000 ft = 15240 m

15240 = (1/2) 0.969 t^2

=> t = 177.33 s

50000 ft / 177.33 s = 281.95 ft/s

Then show me an authoritative source that says so. Also, while you are at it, why don't you do a similar calculation for the F-35A/B/C? That could actually be usefull.

By the way, 281.95 ft/s is 86 m/s. What are you calculating?

The footage shows take off followed by near vertical climb.

 

[CriticalThought]

Then show me an authoritative source that says so. Also, while you are at it, why don't you do a similar calculation for the F-35A/B/C? That could actually be usefull.

By the way, 281.95 ft/s is 86 m/s. Are you calculating initial climb rate (as opposed to max climb rate)?

Average climb rate.

 

[Penguin]

Average climb rate.

Well, why don't you do a comparison calculation for the jets mentioned?

Gripen´s climb rate is said to be 254 m/s (though it doesn’t say at which altitude and speed)

This source below gives the following figures: “Less than 2 minutes from brake release to 10 km (33,000 ft), approx. 3 minutes to 14 km (46,000 ft)”.
http://www.fighter-planes.com/info/jas39.htm

That means a minimum average climb rate of 83 m/s (between brake release to 10000), and a minimum average climb rate of aprox. 78 m/s (between brake release until it reaches 14000).

This puts JF-17 and Gripen quite close, which is what the data posted earlier also showed (at least the key publising forum post).

 

[CriticalThought]

Well, why don't you do a comparison calculation for the jets mentioned?

Isn't everything about F-35 super-classified?

 

[mkg00179504]

I have seen F35 flying demonstration on jones beach. I was there specifically for blue angles but man this thing is so loud and pretty maneuverable too. The tight turns were really good.

 

[Penguin]

Isn't everything about F-35 super-classified?

Your kN seems high.

Anyway, what data do you need for your calculation?

• Loaded weight: 22,426 kg
• Thrust:
  • Dry: 125 kN
    
  • Wet:191 kN

https://en.wikipedia.org/wiki/Lockheed_Martin_F-35_Lightning_II#Specifications_.28F-35A.29

 

[CriticalThought]

Your kN seems high.

Anyway, what data do you need for your calculation?

• Loaded weight: 22,426 kg
• Thrust:
  • Dry: 125 kN
    
  • Wet:191 kN

https://en.wikipedia.org/wiki/Lockheed_Martin_F-35_Lightning_II#Specifications_.28F-35A.29

I computed the average vertical climb rate. The max climb rate would take into account aerodynamic lift.

With the data provided, F-35 will not be able to perform a vertical climb even because T/W is too low.

Also, all of this depends on the load the aircraft is carrying. Since they all belong to different weight classes, the fair comparison would be to fix a proportionate weight between empty and Max take off weight. Even then, some would argue for their fighter it is not a realistic combat load.

Coming back to the video, just try getting a feel for the climb rates in the two videos. You ll feel the difference.

 

[Penguin]

I computed the average vertical climb rate. The max climb rate would take into account aerodynamic lift.

With the data provided, F-35 will not be able to perform a vertical climb even because T/W is too low.

Also, all of this depends on the load the aircraft is carrying. Since they all belong to different weight classes, the fair comparison would be to fix a proportionate weight between empty and Max take off weight. Even then, some would argue for their fighter it is not a realistic combat load.

Coming back to the video, just try getting a feel for the climb rates in the two videos. You ll feel the difference.

But we can see it climbs quite nicely....
I've use the same assumptions you have as to T/W.
Could something be off with your calculation?

General Characteristics
Primary Function: Multirole fighter
Prime Contractor: Lockheed Martin
Power Plant: One Pratt & Whitney F135-PW-100 turbofan engine
Thrust: 43,000 pounds
Wingspan: 35 feet (10.7 meters)
Length: 51 feet (15.7 meters)
Height: 14 feet (4.38 meters)
Maximum Takeoff Weight: 70,000 pound class
Fuel Capacity: Internal: 18,498 pounds
Payload: 18,000 pounds (8,160 kilograms)
Speed: Mach 1.6 (~1,200 mph)
Range: More than 1,350 miles with internal fuel (1,200+ nautical miles), unlimited with aerial refueling
Ceiling: Above 50,000 feet (15 kilometers)
Armament: Internal and external capability. Munitions carried vary based on mission requirements.
Crew: One
http://www.af.mil/About-Us/Fact-She...-ii-conventional-takeoff-and-landing-variant/

 

[Sinnerman108]

None of these numbers is actually authentic as far as Thunder's climb rate is concerned. Using seat of pants calculation, assuming weight of 9100 kg, thrust of 98 kN, and ignoring air resistance, I compute Thunder's climb rate to be 281 ft/s.

Since,

F = m a

98000 N = 9100 a

=> a = 10.769 m/s^2

Net acceleration (ignoring air resistance) = 10.769 - 9.8 = 0.969 m/s^2

Starting from sea level (r = 0) and stationary condition (velocity is 0)

S = (1/2) a t^2

50000 ft = 15240 m

15240 = (1/2) 0.969 t^2

=> t = 177.33 s

50000 ft / 177.33 s = 281.95 ft/s

Naive !

Lift is a function of wing area.
The Larger the wing the more the thrust; and also larger the drag.
Thus Engine thrust becomes a part of the equation;
However looking at the angle of climb,
only a component of thrust contributes to vertical climb.

In your calculations the aircraft is behaving like a rocket doing a vertical climb.