BF-02 Supersonic

Production milestones, roll-outs, test flights, service introduction and other milestones.
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SpudmanWP

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Unread post30 Jun 2010, 16:51

Somewhere I saw a quote from a USAF general that says something like "The number of times the F-15 went above Mach 1.2 in combat can be counted on one hand".

Subsonic/transonic performance is much more important than supersonic most of the time.
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apg77

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Unread post01 Jul 2010, 03:09

SpudmanWP wrote:It represents the time to go from speed X to speed Y, hence "less is more".

This is why the CTOL version has a smaller number than the CV, it accelerates better than the CV and STOVL.


I am doubt about it.

so far as I know, the are some data as below:
1- F-16C's transonic acceleration is much better than F/A-18C.
2- F-35A's transonic acceleration is similar with F-35B. they have similar aerodynamics and engines, but F-35B is heavier.
3--F-35C 's transonic acceleration is worse with F-35A/B, for its bigger wings.

so in the chart ,
less is worse.
F-16C is not compared with F/A-18C.
F-35A is only compared with F-16C,
F-35B/C are only with F/A-18C.

SnakeHandler wrote:I don't know why everyone is so obsessed with top speed and supercruise. Time spent above .95 should be minimized and above 1.2(ish) is wasted on me anyway. For my money, I want a jet that can get fast quickly and efficiently but it doesn't need to stay there. Just one reporter's opinion.


I agree with you, high speed is not very important.

SpudmanWP wrote:Somewhere I saw a quote from a USAF general that says something like "The number of times the F-15 went above Mach 1.2 in combat can be counted on one hand".

Subsonic/transonic performance is much more important than supersonic most of the time.


transonic is important , but it seems that F-35's transonic performance is not as good as F-16.
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munny

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Unread post01 Jul 2010, 03:37

I'm a bit dubious about that acceleration graph too. Less might actually be LESS acceleration. The F-35C is a heavier aircraft and probably higher drag than the B.

It would mean the F-18C has a much lower acceleration than the F-16C which might be true due to its TWR being lower and larger, draggier airframe.
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Unread post01 Jul 2010, 04:18

http://www.livescience.com/technology/0 ... -jets.html
via:
http://www.f-16.net/f-16_forum_viewtopic-t-12412.html

"The F-35 will be able match most of the same high AOA manoeuvres as the Raptor, although it will not be able to do so as quickly as the more powerful jet in some cases. Turning at the higher Gs and higher speed portions of the flight envelope, the F-35 will "almost exactly match a clean Block 50 F-16 and comes very close to the Raptor", Beesley said.

...the four current test pilots for F-35 have been most impressed by the aircraft's thrust and acceleration. In the subsonic flight regime, the F-35 very nearly matches the performance of its' larger, more powerful cousin, the F-22 Raptor, Beesley explained. The "subsonic acceleration is about as good as a clean Block 50 F-16 or a Raptor- which is about as good as you can get." Beesley said.

The outstanding handling, acceleration, and the maximum speed of the aircraft is useable in a combat configuration unlike in legacy fighters. Beesley said that recently he flew an F-35 test flight with a full internal load of two 2000 lbs JDAMs, and two AIM-120 missiles. The aircraft "felt like it had a few thousand pounds of extra fuel" but otherwise Beesley said there was practically no degradation in the aircrafts' performance."

Probably a waste of time to quote someone who has flown the aircraft I guess...

"While supersonically the F-35 is limited to a seemingly unimpressive Mach 1.6 in level flight, Davis explains that the JSF is optimized for exceptional subsonic to supersonic acceleration. Transonic acceleration is much more relevant to a fighter pilot than the absolute max speed of the jet, Davis said. Davis, who was previously the program manager for the F-15 Eagle, explains that while the Eagle is a Mach 2 class fighter, it has rarely exceed the threshold of Mach 1.2 to Mach 1.3 during it's entire 30 year life span. Additionally, the time the aircraft has spent in the supersonic flight regime can be measured in minutes rather than hours- most of the supersonic flights were in fact during specialized flights such as Functional Check Flights (FCF)."
A4G Skyhawk: www.faaaa.asn.au/spazsinbad-a4g/ & www.youtube.com/channel/UCwqC_s6gcCVvG7NOge3qfAQ/videos?view_as=subscriber
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apg77

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Unread post01 Jul 2010, 04:55

I have read this article before,I also think that high speed is not inportant.
this article shows that F-35's subsonic performance is very good.
let's wait the transonic test result, F-35 is still a good plane enen this result is not good.

There are two types of F/A-18C ,each equiped with F404-GE-400 or F-404-GE-402 engines. The F404-GE-402 can improve its transonic acceleration.
Which type does this chart mentioned?
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SpudmanWP

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Unread post01 Jul 2010, 07:20

apg77 wrote:
SpudmanWP wrote:It represents the time to go from speed X to speed Y, hence "less is more".

This is why the CTOL version has a smaller number than the CV, it accelerates better than the CV and STOVL.


I am doubt about it.

so far as I know, the are some data as below:
1- F-16C's transonic acceleration is much better than F/A-18C.
2- F-35A's transonic acceleration is similar with F-35B. they have similar aerodynamics and engines, but F-35B is heavier.
3--F-35C 's transonic acceleration is worse with F-35A/B, for its bigger wings.

so in the chart ,
less is worse.
F-16C is not compared with F/A-18C.
F-35A is only compared with F-16C,
F-35B/C are only with F/A-18C.


You need to take a class on chart reading ;)

Here is the same chart that has been annotated for ease of reading.

Image

Just like in golf, lower is better. The F-16 is lower than the F-18 and the F-35 B/C are also lower than the F-18. As you can see, the F-35 has the lowest number than of all the jets on the list, just as we would expect.
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apg77

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Unread post01 Jul 2010, 07:46

SpudmanWP wrote:You need to take a class on chart reading ;)

Here is the same chart that has been annotated for ease of reading.


You misunderstood what I said.

these info are getted from other source, not from this chart.
but this chart should include them.
1- F-16C's transonic acceleration is much better than F/A-18C.
2- F-35A's transonic acceleration is similar with F-35B. they have similar aerodynamics and engines, but F-35B is heavier.
3--F-35C 's transonic acceleration is worse with F-35A/B, for its bigger wings.

You can devide the chart into 2 parts.
The same length in left and right part have different value.

In this chart, because F-35B's length is longer than F-35C and F-35B'a transonic acceleration is better than F-35C, can conclude that longer is better.
because F--35A's length is shorter than F-35B and F-35B'a transonic acceleration is worse than F-35C, can conclude that length in upper part and down part have different value.
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SpudmanWP

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Unread post01 Jul 2010, 08:10

Who says the F-35B has better Trans Accel than the F-35C?
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wrightwing

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Unread post01 Jul 2010, 12:49

apg77 wrote:
SpudmanWP wrote:It represents the time to go from speed X to speed Y, hence "less is more".

This is why the CTOL version has a smaller number than the CV, it accelerates better than the CV and STOVL.


I am doubt about it.

so far as I know, the are some data as below:
1- F-16C's transonic acceleration is much better than F/A-18C.
2- F-35A's transonic acceleration is similar with F-35B. they have similar aerodynamics and engines, but F-35B is heavier.
3--F-35C 's transonic acceleration is worse with F-35A/B, for its bigger wings.

so in the chart ,
less is worse.
F-16C is not compared with F/A-18C.
F-35A is only compared with F-16C,
F-35B/C are only with F/A-18C.


That chart is pretty clear. The A, B, and C models will out accelerate an F-16 or F-18, the A, B, C models have better instantaneous and sustained turn rates than the F-16 or F-18. THAT is the take away.
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Unread post01 Jul 2010, 13:00

apg77 wrote:
You misunderstood what I said.

these info are getted from other source, not from this chart.
but this chart should include them.
1- F-16C's transonic acceleration is much better than F/A-18C.
2- F-35A's transonic acceleration is similar with F-35B. they have similar aerodynamics and engines, but F-35B is heavier.
3--F-35C 's transonic acceleration is worse with F-35A/B, for its bigger wings.

you can devide the chart into 2 parts.
the same length in left and right part have differnct value.


We understand what you're saying. What we're saying is that you're wrong.
If you look at that chart, the F-16 is quicker than the F-18, but all 3 models of the F-35 are quicker than either the F-16 or F-18. It doesn't matter if you look at the chart the way Lockheed Martin originally had it, or if you cut it into 2 parts like you did. The F-35 in all variants is the quicker aircraft. That chart does show that the F-35A is the quickest model, and then C, then the B.
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apg77

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Unread post01 Jul 2010, 13:38

wrightwing wrote:
We understand what you're saying. What we're saying is that you're wrong.


I think that you are wrong.
let's wait test results.
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johnwill

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Unread post01 Jul 2010, 19:39

And ALL these charts are so much Madison Avenue advertising agency crap until fuel state, weapon load, speed, and altitude are provided.
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Unread post01 Jul 2010, 20:05

apg77 wrote:
wrightwing wrote:
We understand what you're saying. What we're saying is that you're wrong.


I think that you are wrong.
let's wait test results.


What's your source, or is it just a hunch? The manufacturer is the one making this claim(and they build 4 of the 5 aircraft in question).
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apg77

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Unread post02 Jul 2010, 06:14

Ultimate Fighter: Lockheed Martin F-35 Joint Strike Fighter
Bill Sweetman

However, the F-35C is likely to be slower in acceleration then the F-35A, particularly at transonic speeds, because of its larger wing.
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SpudmanWP

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Unread post02 Jul 2010, 06:31

That is exactly what the chart I posted says.

From quickest to slowest (in the chart anyways):

1. F-35A (Baseline time to go from X to Y = 1)
2. F-35C (X to Y = 1.20)
3. F-35B (X to Y = 1.50)
4. F-16C (X to Y = 1.64)
5. F/A-18C (X to Y = 1.69)
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