F-35's max speed conundrum

Something about the F-35's max speed that doesn't make much sense. There's been much complaining about how F-35 is limited to only Mach 1.6 and blah blah blah, but according to the official F-35 documents, the max speed is stated to be around 1200 mph. That speed is close to Mach 1.6 at sea level, but at 30k feet, that's closer to Mach 1.8. Since I don't think F-35, let along any fighter except for maybe MiG-31, will be doing Mach 1.6 at low level, so something doesn't seem right here.

That kind of thing can happen when you are talking about classified information. When only bits and pieces are available for public release -- and those pieces potentially being understated minimums -- not everything will appear consistent. The 1.6 Mach might be the constraint at 15,000 ft, like the other stats seem to be.

Add this factoid to your enigma wrapped in a puzzle wrapped in plastic from fast facts July 2013:

"Speed (full internal weapons load) Mach 1.6 (~1,200 mph)"

https://www.f35.com/assets/uploads/down ... ly2013.pdf

The numbers circulating in public is that the A is limited to KCAS=700 AND MACH=1.6.

IOW at 100ft max KCAS is 700 and M1.06; at 30.000 ft KCAS_max is 683 and M 1.6.

Just remember the Air inlets of F-35. It lacks chock ramp shields and spill vents/doors afaik.
Perhaps this makes more high speed limitation and not so much wave drag or skin heating limitations.

Another thing to consider, is that the F-35 was going to be tested beyond M1.6, so that's not necessarily its absolute limit. It may just be the limit for day to day usage, just like the 50 deg AoA limit is well under the max safe limit (it was tested to over 70 deg AoA).

There we go again...Marine fliers say:
(http://www.flightglobal.com/blogs/the-dewline/2013/08/f-35b-sea-trials-aboard-the-uss-wasp/)

"An interesting factoid, one of the USMC test pilots mentioned this little tidbit—they have to use a modified Rutowski profile in order to get the F-35B and C up to Mach 1.6. Basically, you do one push over, unload the jet and accelerate, get up to 1.2, turn and repeat until you hit 1.4 Mach, turn and repeat till you hit Mach 1.6. It just barely gets there and barely has any gas left over afterwards."

(it's still unclear though, whether this is being done in or out of JSF's proverbial 'combat load')
Anyway, as it turns out the JSF is M1.6 limited not because evil US services refuse to pay for envelope expansion beyond, but because it's a chubby, flying swissknife with little if any envelope beyond...not exactly a surprise, considering design constrains.

Thx a ton cola.
And thanks to USMC for not being a total shutface about the F-35 program.
Hardly surprising. Hense my teasing the F-35 being "Jabba the Hut" kind of jet.
But Seriously, as cola says the confinment of the F-35 program threesome requirement and shape(which to this day hurts my head..why?) is debateble. Like the SH, you can't change wave drag and overall kinematic performance once the design is frozen.

If this is something we can all agree on, then it will be further fruitfull to descuss which speed the F-35 can expect to Reach With external payload.
Why does the wing pylons on F-35 seems so big in size?
Smaller wing or..is this New set of pylons that can be jetison from the hardpoint stations?

cola wrote:There we go again...Marine fliers say:
(http://www.flightglobal.com/blogs/the-dewline/2013/08/f-35b-sea-trials-aboard-the-uss-wasp/)

"An interesting factoid, one of the USMC test pilots mentioned this little tidbit—they have to use a modified Rutowski profile in order to get the F-35B and C up to Mach 1.6. Basically, you do one push over, unload the jet and accelerate, get up to 1.2, turn and repeat until you hit 1.4 Mach, turn and repeat till you hit Mach 1.6. It just barely gets there and barely has any gas left over afterwards."

(it's still unclear though, whether this is being done in or out of JSF's proverbial 'combat load')
Anyway, as it turns out the JSF is M1.6 limited not because evil US services refuse to pay for envelope expansion beyond, but because it's a chubby, flying swissknife with little if any envelope beyond...not exactly a surprise, considering design constrains.

Wow thats quite the editorial there.

Thx a ton cola.
And thanks to USMC for not being a total shutface about the F-35 program.

Oh your welcome, I know you really mean to say "thanks to whoever said that, its what I wanted to hear" it sure made cola happy too.

Its strange because I have heard other opinions that don't say that at all and from Marines as well. Maybe this is worth some analysis?

I'm curious to see exactly what he was talking about and the circumstances in which he was referring. For example, if this is at sea level.I also find it odd that he says:

get up to 1.2, turn and repeat until you hit 1.4 Mach, turn and repeat till you hit [b]Mach 1.6.

Do we all believe that the F-35 must keep turning to continue to accelerate? It sure sounds to me like he is referring to a test cycle where they are running the aircraft up after turning and then repeating that again and again... unless we believe the F-35 has to turn at mach 1.4 before it can accelerate to mach 1.6?

That sure sounds like a test profile to me, especially when its a Marine pilot doing sea trials, in DT II when the headline is "F-35B sea trials" the second part of the quote conveniently left out was:

The kinematics are basically F/A-18C-like, though that was apparently exactly what was expected.

- See more at: http://www.flightglobal.com/blogs/the-d ... LMDOt.dpuf

I've never heard of an F-18 having to do such turns to get to its top speed...

So let me get this straight. An F-35B did a STOVL takeoff, (amount of fuel on board unknown) flew 3 seperate super sonic passes slowing down and turning each time, at an unknown altitude, for testing and then was low on fuel? I'm shocked I tell you, Shocked!



I bet you two feel kind of stupid.

XanderCrews wrote:

cola wrote:There we go again...Marine fliers say:
(http://www.flightglobal.com/blogs/the-dewline/2013/08/f-35b-sea-trials-aboard-the-uss-wasp/)

"An interesting factoid, one of the USMC test pilots mentioned this little tidbit—they have to use a modified Rutowski profile in order to get the F-35B and C up to Mach 1.6. Basically, you do one push over, unload the jet and accelerate, get up to 1.2, turn and repeat until you hit 1.4 Mach, turn and repeat till you hit Mach 1.6. It just barely gets there and barely has any gas left over afterwards."

(it's still unclear though, whether this is being done in or out of JSF's proverbial 'combat load')
Anyway, as it turns out the JSF is M1.6 limited not because evil US services refuse to pay for envelope expansion beyond, but because it's a chubby, flying swissknife with little if any envelope beyond...not exactly a surprise, considering design constrains.

Wow thats quite the editorial there.

Thx a ton cola.
And thanks to USMC for not being a total shutface about the F-35 program.

Oh your welcome, I know you really mean to say "thanks to whoever said that, its what I wanted to hear" it sure made cola happy too.

Its strange because I have heard other opinions that don't say that at all and from Marines as well. Maybe this is worth some analysis?

I'm curious to see exactly what he was talking about and the circumstances in which he was referring. For example, if this is at sea level.I also find it odd that he says:

get up to 1.2, turn and repeat until you hit 1.4 Mach, turn and repeat till you hit [b]Mach 1.6.

Do we all believe that the F-35 must keep turning to continue to accelerate? It sure sounds to me like he is referring to a test cycle where they are running the aircraft up after turning and then repeating that again and again... unless we believe the F-35 has to turn at mach 1.4 before it can accelerate to mach 1.6?

That sure sounds like a test profile to me, especially when its a Marine pilot doing sea trials, in DT II when the headline is "F-35B sea trials" the second part of the quote conveniently left out was:

The kinematics are basically F/A-18C-like, though that was apparently exactly what was expected.

- See more at: http://www.flightglobal.com/blogs/the-d ... LMDOt.dpuf

I've never heard of an F-18 having to do such turns to get to its top speed...

So let me get this straight. An F-35B did a STOVL takeoff, (amount of fuel on board unknown) flew 3 seperate super sonic passes slowing down and turning each time, at an unknown altitude, for testing and then was low on fuel? I'm shocked I tell you, Shocked!



I bet you two feel kind of stupid.

I'm confused.. first i'm feeling glad, but then stupid. I do not think it can be both at the same time.
And b.t.w. we are buying the F-35A Version remember.. so why should i feel glad.. i should rather feel stupid in the first Place then.

Ok, enough of this jabbing nonsens.

The Article state the B and C Version.
The Article states they turned a few times and unloaded some weapons or ordinance.
Gee, i'll bet something like that will never happen in real operationel service. No it means not fly in a straight heading and back agin..
Beside, turnin at those speed is pretty reative, doesn't mean they bleed Maximum energy turn does it?
What is the airspeed after one of those turns? how long distance or time does the F-35 B and C need to get up to Mach 1.6 really?
More importantly, at which altitude?

It sounds like they test fly in a Box route from take off to landing.
Sounds like pretty fair to me.

In this context, "unload" means to take the aircraft into a 0 g give so that the wings are no longer providing lift and the induced drag is zero. The "turning" part is odd, because that could imply that they were having to get up to max speed inside of a smallish geographical box.

I would guess the supersonic test corridor is along the water feature as shown in this map from:

"Atlantic Test Range (ATR), consisting of land, air, and sea ranges in the Chesapeake Bay area, is the Navy’s principal location for the research, development, test, and evaluation of Naval aircraft. The range’s restricted airspace is a critical national asset that allows for training missions and the concurrent testing of multiple new aircraft, including unmanned aerial systems. This restricted airspace, as well as Naval Air Station (NAS) Patuxent River (ATR’s host installation) and Outlying Field (OLF) Webster, encompasses a vast ecologically sensitive area, including Maryland’s Eastern Shore of the Chesapeake.

With the inherent risk in test flights, as well as the noise from aircraft (including supersonic operations), the Navy is working to limit incompatible development underneath the test range airspace and installation flight routes."

http://www.repi.mil/Documents/FactSheet ... ojects.pdf (3.2Mb)

haavarla wrote:

XanderCrews wrote:

cola wrote:There we go again...Marine fliers say:
(http://www.flightglobal.com/blogs/the-dewline/2013/08/f-35b-sea-trials-aboard-the-uss-wasp/)

"An interesting factoid, one of the USMC test pilots mentioned this little tidbit—they have to use a modified Rutowski profile in order to get the F-35B and C up to Mach 1.6. Basically, you do one push over, unload the jet and accelerate, get up to 1.2, turn and repeat until you hit 1.4 Mach, turn and repeat till you hit Mach 1.6. It just barely gets there and barely has any gas left over afterwards."

(it's still unclear though, whether this is being done in or out of JSF's proverbial 'combat load')
Anyway, as it turns out the JSF is M1.6 limited not because evil US services refuse to pay for envelope expansion beyond, but because it's a chubby, flying swissknife with little if any envelope beyond...not exactly a surprise, considering design constrains.

Wow thats quite the editorial there.

Thx a ton cola.
And thanks to USMC for not being a total shutface about the F-35 program.

Oh your welcome, I know you really mean to say "thanks to whoever said that, its what I wanted to hear" it sure made cola happy too.

Its strange because I have heard other opinions that don't say that at all and from Marines as well. Maybe this is worth some analysis?

I'm curious to see exactly what he was talking about and the circumstances in which he was referring. For example, if this is at sea level.I also find it odd that he says:

get up to 1.2, turn and repeat until you hit 1.4 Mach, turn and repeat till you hit [b]Mach 1.6.

Do we all believe that the F-35 must keep turning to continue to accelerate? It sure sounds to me like he is referring to a test cycle where they are running the aircraft up after turning and then repeating that again and again... unless we believe the F-35 has to turn at mach 1.4 before it can accelerate to mach 1.6?

That sure sounds like a test profile to me, especially when its a Marine pilot doing sea trials, in DT II when the headline is "F-35B sea trials" the second part of the quote conveniently left out was:

The kinematics are basically F/A-18C-like, though that was apparently exactly what was expected.

- See more at: http://www.flightglobal.com/blogs/the-d ... LMDOt.dpuf

I've never heard of an F-18 having to do such turns to get to its top speed...

So let me get this straight. An F-35B did a STOVL takeoff, (amount of fuel on board unknown) flew 3 seperate super sonic passes slowing down and turning each time, at an unknown altitude, for testing and then was low on fuel? I'm shocked I tell you, Shocked!



I bet you two feel kind of stupid.

I'm confused.. first i'm feeling glad, but then stupid. I do not think it can be both at the same time.
And b.t.w. we are buying the F-35A Version remember.. so why should i feel glad.. i should rather feel stupid in the first Place then.

Ok, enough of this jabbing nonsens.

The Article state the B and C Version.
The Article states they turned a few times and unloaded some weapons or ordinance.
Gee, i'll bet something like that will never happen in real operationel service. No it means not fly in a straight heading and back agin..
Beside, turnin at those speed is pretty reative, doesn't mean they bleed Maximum energy turn does it?
What is the airspeed after one of those turns? how long distance or time does the F-35 B and C need to get up to Mach 1.6 really?
More importantly, at which altitude?

It sounds like they test fly in a Box route from take off to landing.
Sounds like pretty fair to me.

Let's quote the unload ordnance vs unload the wing mistake to preserve haavarla's credibility for posterity.

shingen wrote:
Let's quote the unload ordnance vs unload the wing mistake to preserve haavarla's credibility for posterity.

Agreed

That testing range is right over the shipping channel. That would have been fun to be on a cruise ship going through there while they were doing supersonic tests.