The F-35 Thread

[Hummingbird]

I kinda agree, however, the F-35A was created to replace the F-16C/D, and if countries such as Belgium are replacing the F-16s by F-35As, what's the problem? Just because the F-35 is a bit slower?

 

The problem is likely when used in the interceptor role to safeguard national airspace, which is what Denmark is and will mostly be using its fighters for.

 

Our F-16's standing at the ready loaded for the interceptor role are real hotrods with just a centerline tank and 4x missiles, i.e. basically completely clean.

[Rangi]

Can you at least try and keep it F-35 relevant. If you want to have an aerodynamics w^nk, start a new thread.

[Darkbrotherhood7]

The problem is likely when used in the interceptor role to safeguard national airspace, which is what Denmark is and will mostly be using its fighters for.

 

Our F-16's standing at the ready loaded for the interceptor role are real hotrods with just a centerline tank and 4x missiles, i.e. basically completely clean.

 

Yeah, but what is the technical problem/concern that makes you believe the F-35A as an interceptor will not be as good as the F-16AM?

[Hummingbird]

Yeah, but what is the technical problem/concern that makes you believe the F-35A as an interceptor will not be as good as the F-16AM?

 

I fear it won't climb as well or be able to reach the same intercept speed as those basically clean F-16's, and then IF it comes to a scenario where the sensors don't live up to the task due to improvements in ECM tech and a good old WVR fight is necessary then I'm worried about the kinematic performance.

 

Now in summary does that mean we're going to be worse off capability wise with the F-35 when we get them as opposed to with the F-16? No, not by a long shot, it just means we likely should've went with an interim 4.5th gen aircraft until a more appropiate aircraft for our needs hit the market - i.e. I'm sure the Gripen could've served us well until that day for a fraction of the price it now costs us to acquire the F-35.

 

But we chose the F-35A so by now I'm just hoping it doesn't break our budget in the end.

[Hummingbird]

Can you at least try and keep it F-35 relevant. If you want to have an aerodynamics w^nk, start a new thread.

 

Exactly that was done, yet the mods decided to merge it with this thread.

[Tirak]

Exactly that was done, yet the mods decided to merge it with this thread.

 

The premise of your other thread was F-35 vs F-16, that's an F-35 thread. As long as you two are talking comparative aerodynamics with respect to the F-35, then there's no reason to have another thread about it, especially not with F-35 in the title.

[garrya]

garrya,

 

I sigh because you so often ignore what's being said and because you fixate on tiny phrases, pick them out, and then address them completely out of context.

 

But let me show you how high an ITR the F-16 can achieve at high speed despite its' CAT system in comparison to the F-15 which features no such system:

 

 

 

 

ITR @ Mach 0.8

F-16 = 19 deg/sec

F-15 = 19 deg/sec

 

Not a big difference is it? Infact pretty much nonexistant...

 

The differences you'll find are at lower speeds and even then they're so small it's not at all important, esp. considering the mind blowingly high STR of the F-16.

 

In short the CAT system is no limitation at high speeds other than making sure that the load limit isn't breached.

 

 

why do you take F-15 as an example ??

F-15 doesnot have Leading edge flap , while both F-16 and F-35 does , which mean both F-16 and F-35 can move their LEF to generate highest possible CL regardless of AoA

 

F-15 doesnot have vortex creating device while both F-16 and F-35 ( as shown in previous page )

 

F-15 is positive stable while both F-16 and F-35 are negative stable which means in WVR engagement the F-15 tail is down loaded, meaning the wing and fuselage must provide additional lift, that not the case for either F-16 or F-35.

 

F-15 CLmax is 1.2 AFAIK

 

So why dont you compare it to something more comparable ? Take for example Su-27 which have not only vortex creating device ( LERX ) but also LEF and it is negative stable too. Now if you look at Su-27 manual

At Mach 0.5 its max AoA is 24 => CL is 1.85

At Mach 0.6 its max AoA is 23 => CL is 1.7

At Mach 0.7 its max AoA is 22 => CL is 1.58

At Mach 0.8 its max AoA is 20 => CL is 1.45

On the other hand, when F-16 makes 9G turn regardless of speed , its max AoA is 15 degrees => CL is about 1

 

Lift = 1/2*V^2*reference wing area*air density *CL

 

Take for example when speed is mach 0.5 ( about 164 meters/sec) => CL is 1.85

air density at sea level is about 1.2kg/m3

Su-27 wing area is about 62m2

so total amount of lift is 1.85 * 1/2 * 1.2 * 164.8^2 * 62 = 1879085N

Su-27 empty weight is 16380 kg, max internal fuel is 9400 kg, Su-27 with 50% fuel will weight about 21080 kg

max G it can pull based on lift generated is 1879085/9.81/21080 =about 9G

that is more than 30 degree/second ITR

On the other hand ,in the same condition ( sea level , mach 0.5) an F-16C with drag index =0 will have maximum instantaneous G of 7G and ITR = 24 degrees/second. More than 5 degrees/seconds different in turn rate, all from much higher CL achieved at higher AoA.

 

Now on to the issue of AoA vs Structure integrity , even at Mach 0.7 , Su-27 can still maintain AoA of 22 degrees , and as a result it is able to achieve much higher CL than F-16, there is no reason to believe that F-35 structure is much weaker than Su-27 or even weaker at all, so more than 15 degrees AoA at dogfight speed is completely flexible.

 

And if F-14 can still dogfight with F-16 even though its main advantage concentrated around Mach 0.55-0.6 then there is no reason why F-35 couldnt. Especially consider that F-35 has a massively powerful engine that will allow it to regain speed very quick after a hard turn and it also has impressive yaw rate of over 28 degrees/second

Edited November 17, 2016 by garrya

[garrya]

Interesting charts Darkbrother, thanks.

 

It's clear when looking at the F-15 for reference that they're using an F-16 with wing bags for the comparison though as the F-16's STR is higher than that of the F-15 under most conditions. Albeit again pilot opinions as always differ wildly.

 

.

 

It is with jettison external fuel tanks

Thirty-one experienced pilots currently flying the F-35A were asked to rate the energy and maneuvering characteristics of their previous fourth-generation fighters in a combat configuration throughout the dogfighting maneuver envelope in a combat configuration after jettisoning their external stores. They were then asked to rate the performance of the F-35A using the same scale, with fuel and internal munition loads associated with a combat loadout[24] under their current G and CLAW restrictions.[25] The F-35A compared well to the four other fighters (F-15C, F-15E, F-16C, and A-10) in most every regime.

Higher sustain turn rate of F-15 could be due to high altitude or different fuel load

Edited November 17, 2016 by garrya

[SkateZilla]

Lol..

[Basher54321]

I fear it won't climb as well or be able to reach the same intercept speed as those basically clean F-16's, and then IF it comes to a scenario where the sensors don't live up to the task due to improvements in ECM tech and a good old WVR fight is necessary then I'm worried about the kinematic performance.

 

Now in summary does that mean we're going to be worse off capability wise with the F-35 when we get them as opposed to with the F-16? No, not by a long shot, it just means we likely should've went with an interim 4.5th gen aircraft until a more appropriate aircraft for our needs hit the market - i.e. I'm sure the Gripen could've served us well until that day for a fraction of the price it now costs us to acquire the F-35.

 

But we chose the F-35A so by now I'm just hoping it doesn't break our budget in the end.

 

The only valid concern is cost really and more likely running cost rather than unit cost which represents amazing value for the F-35 due to economies of scale. I imagine back in 1980 people saying the F-16A couldn't do M2 at 60,000ft or carry 750 rounds of 20mm like the F-104G but I would have taken the F-16 any day.

 

The Danish haven't been too keen to upgrade their F-16s have they - and they only recently upgraded the ancient PW-200s for the higher thrust 220s and it would appear they use the (7?) old Block 10s for QRA that can only be upgraded to an older MLU tape and cannot actually carry TGPs or AIM-120. So when you say clean they are literally in the same config as Israeli Block 5/10 jets were in 1982!

 

I am surprised they are considering the F-35 and the RDAF should consider themselves lucky considering it is night and day in capability over any current 4th or 4.5Gen.

Edited November 17, 2016 by Basher54321

[Hummingbird]

Basher,

 

I can't remember the exact block of F-16 the RDAF operates, but they operate with both AIM-120, AIM-9X & TGP.

 

[Hummingbird]

It is with jettison external fuel tanks

 

Says who? Based on the STR comparison it certainly isn't.

[The Black Swan]

Says who? Based on the STR comparison it certainly isn't.

 

Read the second quote in his post.

[Darkbrotherhood7]

Basher,

 

I can't remember the exact block of F-16 the RDAF operates, but they operate with both AIM-120, AIM-9X & TGP.

 

It's an F-16AM Block 20 MLU AFAIK.

Edited November 17, 2016 by Darkbrotherhood7

[Basher54321]

Basher,

 

I can't remember the exact block of F-16 the RDAF operates, but they operate with both AIM-120, AIM-9X & TGP.

 

 

That photo is one of the 30 or so Block 15s - they are supposedly at MLU Tape 6.5 and they are the ones used for international operations - but apparently there are 7 old Block 10s stuck at Tape 4.3 used for QRA only that cannot carry AIM-120 & TGPs.

 

Block 20 is often used for an MLU but the airframes were originally manufactured as Block 1, 5 10, 15 and 15 OCU across the EPAF nations.

 

The RDAF had 44 F-16AM/BM MLU (Block 10 & 15) in service as of June 2016 according to scandinavian mag FlyMag

[Hummingbird]

why do you take F-15 as an example ??

F-15 doesnot have Leading edge flap , while both F-16 and F-35 does , which mean both F-16 and F-35 can move their LEF to generate highest possible CL regardless of AoA

 

F-15 doesnot have vortex creating device while both F-16 and F-35 ( as shown in previous page )

 

F-15 is positive stable while both F-16 and F-35 are negative stable which means in WVR engagement the F-15 tail is down loaded, meaning the wing and fuselage must provide additional lift, that not the case for either F-16 or F-35.

 

F-15 CLmax is 1.2 AFAIK

 

So why dont you compare it to something more comparable ? Take for example Su-27 which have not only vortex creating device ( LERX ) but also LEF and it is negative stable too. Now if you look at Su-27 manual

At Mach 0.5 its max AoA is 24 => CL is 1.85

At Mach 0.6 its max AoA is 23 => CL is 1.7

At Mach 0.7 its max AoA is 22 => CL is 1.58

At Mach 0.8 its max AoA is 20 => CL is 1.45

On the other hand, when F-16 makes 9G turn regardless of speed , its max AoA is 15 degrees => CL is about 1

 

Lift = 1/2*V^2*reference wing area*air density *CL

 

Take for example when speed is mach 0.5 ( about 164 meters/sec) => CL is 1.85

air density at sea level is about 1.2kg/m3

Su-27 wing area is about 62m2

so total amount of lift is 1.85 * 1/2 * 1.2 * 164.8^2 * 62 = 1879085N

Su-27 empty weight is 16380 kg, max internal fuel is 9400 kg, Su-27 with 50% fuel will weight about 21080 kg

max G it can pull based on lift generated is 1879085/9.81/21080 =about 9G

that is more than 30 degree/second ITR

On the other hand ,in the same condition ( sea level , mach 0.5) an F-16C with drag index =0 will have maximum instantaneous G of 7G and ITR = 24 degrees/second. More than 5 degrees/seconds different in turn rate, all from much higher CL achieved at higher AoA.

 

Now on to the issue of AoA vs Structure integrity , even at Mach 0.7 , Su-27 can still maintain AoA of 22 degrees , and as a result it is able to achieve much higher CL than F-16, there is no reason to believe that F-35 structure is much weaker than Su-27 or even weaker at all, so more than 15 degrees AoA at dogfight speed is completely flexible.

 

And if F-14 can still dogfight with F-16 even though its main advantage concentrated around Mach 0.55-0.6 then there is no reason why F-35 couldnt. Especially consider that F-35 has a massively powerful engine that will allow it to regain speed very quick after a hard turn and it also has impressive yaw rate of over 28 degrees/second

 

Hehe, first of all clmax isn't uniform at the same AoA across all speed ranges, secondly your simple math exercise fails to even consider the lift generated by the fuselage, which is over half of the total lift in the case of the Su-27 with its massive and highly optimized true lifting body design heavily influenced by the F-14.

 

As a result the Su-27 features a lift loading lower than that of most fighters, esp. at low speeds, which is what provides it with such amazing low speed agility. It would make a mockery of the F-35 in a classic dogfight.

 

In other words it's a pretty poor comparison with both the F-16 & F-35.

 

Also you would've been better off by simply showing the Su-27's EM chart...

Edited November 17, 2016 by Hummingbird

[Ktulu2]

Dimensions, video footage etc..

 

For example one thing that immediately struck me watching the F-35A flying in formation at low speeds with F-16's following a chase plane was how high an AoA the F-35 needed to maintain just to stay airborne. This in itself indicates a high lift loading.

 

While lift is proportional to AoA, the coefficient that determines the effect of AoA on lift (CM or C alpha) depends to a reasonable amount on the wing type (even on basic NACA 00XX wings) , so that's not only the wing loading's effect and you can only get rough ideas by visual analysis. (This is especially true on non-100% symetric wings, like many fighters, AND is the case of the F-35 (NACA 64-206))

And than, you have to consider the fact the F-35 could have 100% internal, while the F-16s were in internal too (at least, in the pics i've seen) so that trows off the WL estimation by A LOT. I've seen pics where the -35 has the same AoA as vipers.

Edited November 18, 2016 by Ktulu2

[mvsgas]

Basher54321,

F-16.net has a list of all RDAF F-16, here you can see the active, stored, destroyed, etc F-16. AFAIK, all active F-16 in the RDAF are consider block 20, but to what tape and what capabilities they posses is on a aircraft to aircraft bases. I am not disputing what you said nor contradicting it, just trying to provide a good source/reference link for everyone in the conversion to see.

 

http://www.f-16.net/aircraft-database/F-16/serials-and-inventory/airforce/RDAF/1/

[mvsgas]

 

The photo/picture looks fake considering it does not have the normal RDAF E-#### (normally found on single seat A/AM models in the RDAF)on the side of the aircraft.

I see a similar picture used on an news article referring to the E-070 (83-1070) which was originally a block 15Q converted to block 20 but I can not tell if the photo is related.

Edited November 18, 2016 by mvsgas

[Hummingbird]

That photo is one of the 30 or so Block 15s - they are supposedly at MLU Tape 6.5 and they are the ones used for international operations - but apparently there are 7 old Block 10s stuck at Tape 4.3 used for QRA only that cannot carry AIM-120 & TGPs.

 

Block 20 is often used for an MLU but the airframes were originally manufactured as Block 1, 5 10, 15 and 15 OCU across the EPAF nations.

 

The RDAF had 44 F-16AM/BM MLU (Block 10 & 15) in service as of June 2016 according to scandinavian mag FlyMag

 

If that's so it's a mystery to me why we ever chose the F-35 if we earlier haven't even been willing to upgrade our QRA aircraft to the same std. as the rest of our fleet. But ofcourse this shouldn't come as a surprise considering how our politicians treat the military :disgust:

 

Here's a couple of them, and indeed they're carrying only AIM-9's, and not even X's:

[Hummingbird]

The photo/picture looks fake considering it does not have the normal RDAF E-#### (normally found on single seat A/AM models in the RDAF)on the side of the aircraft.

I see a similar picture used on an news article referring to the E-070 (83-1070) which was originally a block 15Q converted to block 20 but I can not tell if the photo is related.

 

I think it's just the light hitting at an angle, but here are a few more pictures:

 

Edited November 18, 2016 by Hummingbird

[mvsgas]

If that's so it's a mystery to me why we ever chose the F-35 if we earlier haven't even been willing to upgrade our QRA aircraft to the same std. as the rest of our fleet. But ofcourse this shouldn't come as a surprise considering how our politicians treat the military :disgust:

 

Here's a couple of them, and indeed they're carrying only AIM-9's, and not even X's:

 

I think all of those are retired, stored or Scrapped.

Edited November 18, 2016 by mvsgas

[Rangi]

I think all of those are retired, stored or Scrapped.

 

And they are definitely not F-35s......

[mvsgas]

And they are definitely not F-35s......

 

:doh: They are not?! Wow, I really got it wrong, did not know that, thanks.:smartass:

[Hummingbird]

Rangi,

 

I am as annoyed by the merging of threads as you are, but there needs to be a place where we can discuss the F-35 in comparison with other aircraft, and if this isn't the place then where? The moderators merge every such thread with this one, thus if you're you're looking for a "F-35 news only" thread then maybe you'll have luck by creating one that the mods don't auto merge with this one - if not then we're kind forced to do it here.