The F-35 Thread

[probad]

Alright, I'm more interested in trying to reconcile the F-35's performance with theory. The report is now that the F-35 actually stacks up pretty well vs F-16/18 so I'm curious how you think that can be, even though it is in your opinion, missing some of the most important aerodynamic features of those aircraft?

[Hummingbird]

Further down the page is where you start running into trouble, when you start declaring characteristics of the F-35's wing and body design based on... well nothing.

 

Emphasis mine. The fact is, you don't know that, and stating it in the imperative form indicates you make the claim as a statement of fact, and that's where you run into trouble.

 

You need to consider what I'm saying as a whole and not just jump at short single phrases though.

 

In that phrase was refering to the blended wing body design and for what purpose the airframes seem to be optimized.

[Hummingbird]

Alright, I'm more interested in trying to reconcile the F-35's performance with theory. The report is now that the F-35 actually stacks up pretty well vs F-16/18 so I'm curious how you think that can be, even though it is in your opinion, missing some of the most important aerodynamic features of those aircraft?

 

The report mostly concerns initial pitch rate and high AoA authority, something we already sort of knew that the F-35 was going to possess based on already "leaked" information.

 

What we don't know is how well the F-35 will stack up against the other aircraft in terms of climb, STR and acceleration.

 

I'm really curious as to how well it would stack up to an F-16, Eurofighter or Gripen configured for a high speed emergency intercept. The reason for that being that our country needs a fast interceptor to protect our airspace.

[GGTharos]

Having seen some intercept profiles, the only thing here that would do it significantly better (IMHO, and on limited info) than an F-35 is the EF.

 

I would expect the 35 to out-perform the others actually, and you have the advantage of the incoming having problems cueing weapons on your jets.

 

Having said that, it doesn't mean it's the best fit.

[NineLine]

 

I'm really curious as to how well it would stack up to an F-16, Eurofighter or Gripen configured for a high speed emergency intercept. The reason for that being that our country needs a fast interceptor to protect our airspace.

 

 

Have they said the F-35 will be used in a Interceptor role?? I thought that was what the F-22 is supposed to handle...

[GGTharos]

For countries that don't employ multiple types of aircraft, that would be a role the F-35 would have to cover.

[NineLine]

For countries that don't employ multiple types of aircraft, that would be a role the F-35 would have to cover.

 

Your right, for whatever reason I was thinking HB was speaking from a US position, but most likely not talking about the US... oops...

[Tirak]

Have they said the F-35 will be used in a Interceptor role?? I thought that was what the F-22 is supposed to handle...

 

Based on his statement, I'm going to assume Hummingbird is Canadian, in which case, the F-35 will be the front line fighter for all roles.

 

With that in mind, Canada's fighter procurement needs to balance capability and cost. The F-35 is currently falling in price, with program estimates that the cost will be 80-85 million in the year 2020. The Eurofighter is much more expensive, lacks stealth, and lacks the advanced senor systems that the F-35 has. While the Eurofighter performs better in a dogfight, it does not choose the fight like the F-35 can. For high speed supersonic dash it beats the F-35 flat out, but that is required only for bomber interception.

 

The Gripen is... a mass of conflicting and shifting information and something I nolonger feel confident giving accurate information on for the time being. What SAAB claims and what the aircraft has demonstrated are wildly out of sync, and I would hesitate to push for it.

 

The Super Hornet suffers from many of the shortcomings of the Eurofighter, being non stealthy, and no DAS, but also has short legs, very limited weapons carrying capacity, and furthermore drasitic aerodynamic shortcomings the moment you place weapons on the plane due to an... odd pylon arrangement. A flat dash the F-18 can outrun an F-35 over distance, but again, it suffers from very poor range, and the moment you put wing tanks on it, the speed advantage disappears entirely. To add to this, the Super Hornet line needs to produce 12 aircraft a year to maintain an affordability point below the F-35, something that is only going to happen for another 2 years thanks to the Kuwait order., meaning if Canada doesn't buy them now then they'll be paying more for them than they would the F-35, and that once a line stops, price for replacement parts surges.

[Donut]

Have they said the F-35 will be used in a Interceptor role?? I thought that was what the F-22 is supposed to handle...

 

Wouldn't the F-35C have to fill that role for the U.S. Navy? While we are speaking of roles, will there be F-35's that are designated as tankers like we see now with the Super Hornet?

[Tirak]

Wouldn't the F-35C have to fill that role for the U.S. Navy? While we are speaking of roles, will there be F-35's that are designated as tankers like we see now with the Super Hornet?

 

The Navy is looking at using the V-22 for its tanker needs going forward if I recall correctly.

[NineLine]

Based on his statement, I'm going to assume Hummingbird is Canadian, in which case, the F-35 will be the front line fighter for all roles.

 

I dont think he is Canadian, but I agree, I jumped to a conclusion there. That said... isnt Stealth supposed to be a big deal for interceptors, being able to intercept outside visual range and before they can see you.

[Hummingbird]

I was talking about Denmark guys, I'm Danish. Hence why I often compare the F-35 with the F-16 :)

[Emu]

Right in the document you found - LOAL capability typically implies data-link as well as other electronics like INS/GPS. Having said that, data-link not strictly necessary but not having it can easily reduce Pk.

I can't find evidence of it having a datalink anyway but it still managed LOAL fine in tests. CAMM does have a datalink though.

 

http://www.yourindustrynews.com/raaf+has+successfully+fired+asraam+at+a+target+located+behind+the+wing-line+of+the+%E2%80%98shooter%E2%80%99+aircraft_26109.html

http://defense-update.com/newscast/0309/asraam_loal_test_130309.html

 

This engagement simulated a "chase down" situation by an enemy fighter and successfully demonstrated the potential for an all-round self protection capability with the ASRAAM. The missile was fired at a target located behind the wing-line of the ‘shooter’ aircraft, flying at low level and typical fighter speed, at a target located behind the fighter at a range in excess of 5km. The result was a direct hit on the target. This capability is inherent on all platforms that provide pre-launch 'over the shoulder' designation information such as F/A-18, Eurofighter Typhoon and F-35 JSF.

 

Acceleration is not determined by rocket diameter - you can use it as a rule of thumb I guess, but that's not right. Even with ASRAAM you will get two different accelerations (boost-sustain grain).

Anyway, thanks for finding that document - it looks official (is it? :) ), and it says the things I'm interested in, ie: 'More propellant' which is the important part for making a big difference in range, and 'Lifting body' which is itself important.

Thanks, the document is internet archived from MBDA's site, they changed the site recently. So yes, it's official.

 

Definitely not. Reduction of drag requires a boat-tail, and ASRAAM has 'more' boat-trail than AIM-9X, which is part of why I keep saying it's a cleaner missile :)

I thought TVC did augment lift, therefore reducing drag in high speed turns. Isn't that why the F-22 uses it?

 

There was also a proposal to change the rocket motor (and possibly the missile airframe) - the AIM-9X Block III modification, to extend range. But it was cancelled, and it is expected that AIM-9X Block II can achieve a BVR-ish range with the help of lofting profiles. It won't get there as fast as an ASRAAM and won't go as far though given the above data.

 

I expect the Block III type program to be re-started when someone gets the budget back on track, but you never know.

Maybe an IIR option will be added to CUDA?

 

The interesting thing is that CAMM is supposedly a new variant based on ASRAAM for land, sea and air based anti-air, so we may see an air-launched derivative with even better range than ASRAAM, hence I wondered what was meant by 'ASRAAM New Build'.

[Pilotasso]

The F-35 is currently falling in price, with program estimates that the cost will be 80-85 million in the year 2020. The Eurofighter is much more expensive, lacks stealth, and lacks the advanced senor systems that the F-35 has. While the Eurofighter performs better in a dogfight, it does not choose the fight like the F-35 can. For high speed supersonic dash it beats the F-35 flat out, but that is required only for bomber interception.

 

 

The Super Hornet suffers from many of the shortcomings of the Eurofighter, being non stealthy, and no DAS, but also has short legs, very limited weapons carrying capacity, and furthermore drasitic aerodynamic shortcomings the moment you place weapons on the plane due to an... odd pylon arrangement. A flat dash the F-18 can outrun an F-35 over distance, but again, it suffers from very poor range, and the moment you put wing tanks on it, the speed advantage disappears entirely. To add to this, the Super Hornet line needs to produce 12 aircraft a year to maintain an affordability point below the F-35, something that is only going to happen for another 2 years thanks to the Kuwait order., meaning if Canada doesn't buy them now then they'll be paying more for them than they would the F-35, and that once a line stops, price for replacement parts surges.

 

I disagree with the above excerpt from your post.

 

The Eurofighter and superhornet both have advanced radars, the EF in particular will have an AESA unit, likely before the F-35 shows up in significant numbers.

 

EF approaches the AA problem from a different angle, instead of stealth it will shoot at a distance beyond the reach of its opposition using meteors with the corresponding variance in tactics that implies (and SH).

 

The SH in particular has likely the 3rd lowest RCS value of any fighter under the F-22 right now.

 

There is a large amount of imagination put forth in your post by saying SH and EF are crap. They are world class fighters and are in service today.

 

If any capability can be doubted in any of the 3 planes, it is the interceptor role for the F-35. I have said this before many times. The fleets that will adopt the F-35 as their single fleet type will always be tempted to let their partner nations take over that role with other types (likely SH and EF) rather than doing it themselves.

 

Its just enjoying some of the generational gap advantages for now, and that wont last for long (compared to its projected service life).

[Tirak]

The Eurofighter and superhornet both have advanced radars, the EF in particular will have an AESA unit, likely before the F-35 shows up in significant numbers.

 

True, except both the Super Hornet and Eurofighter will not have DAS, or an integrated targeting pod. Therefore, both aircraft do not have as good sensors as the F-35.

 

EF approaches the AA problem from a different angle, instead of stealth it will shoot at a distance beyond the reach of its opposition using meteors with the corresponding variance in tactics that implies (and SH).

 

Again, very true, for the Eurofighter, however extreme range shots have a lower chance of actually hitting the target, and increasing range of missile technology is much easier than coming up with an airborne radar capable of locking a stealth aircraft to take advantage of that range capability. Additionally, the F-35 will also have Meteor, meaning at best, this puts them on parity, but in reality, the F-35 maintains a BVR advantage, though still being at a disadvantage in WVR combat.

 

The SH in particular has likely the 3rd lowest RCS value of any fighter under the F-22 right now.

 

While stealth is certainly not a binary concept, saying that the Super Hornets 'low rcs value' is of any real advantage in a fight between two technologically advanced nations is a laughable claim.

 

There is a large amount of imagination put forth in your post by saying SH and EF are crap. They are world class fighters and are in service today.

 

At no point do I say this, I merely point out the advantages that a stealth aircraft with the most advanced sensor fusion on a fighter has.

 

If any capability can be doubted in any of the 3 planes, it is the interceptor role for the F-35. I have said this before many times. The fleets that will adopt the F-35 as their single fleet type will always be tempted to let their partner nations take over that role with other types (likely SH and EF) rather than doing it themselves.

 

Its just enjoying some of the generational gap advantages for now, and that wont last for long (compared to its projected service life).

 

Time will tell :smilewink:

[RAZBAM_ELMO]

Yeah us Canucks are still using gen4 lagacies......f16s would be called like beavers or chickadees some small annoying ferocious animal

 

Sent from my SM-G900W8 using Tapatalk

[GGTharos]

I can't find evidence of it having a datalink anyway but it still managed LOAL fine in tests. CAMM does have a datalink though.

 

I'm referring to the history of LOAL launches used without m-link ... the results were poor. :)

 

Thanks, the document is internet archived from MBDA's site, they changed the site recently. So yes, it's official.

 

Good deal :)

 

I thought TVC did augment lift, therefore reducing drag in high speed turns. Isn't that why the F-22 uses it?

 

Ah ok, I think I see what you mean: This is used to reduce trim drag and is (AFAIK) most useful during cruise, allowing the aircraft to deflect the horizontal stabilizers less. Regarding high-speed turns, I'm not sure it's used at all unless it's at supersonic speeds ... but the physics of those turns are a little different AFAIK.

 

In a missile, TVC is typically used to reduce Rmin in the initial turn.

 

Maybe an IIR option will be added to CUDA?

 

The interesting thing is that CAMM is supposedly a new variant based on ASRAAM for land, sea and air based anti-air, so we may see an air-launched derivative with even better range than ASRAAM, hence I wondered what was meant by 'ASRAAM New Build'.

 

I think CUDA is just a thing on paper right now, but we will see :)

[Hummingbird]

Wasn't there a Lockheed report some years back that put the F-35A's sustained load factor at ~4.9 G's at Mach 0.8 at 15 kft? This whilst armed with two AMRAAMs internally.

 

If this is at all indicative of the current iterations' performance then that would mean its STR is little better if at all than that of an F-4 Phantom.

[garrya]

How is are pictures from that angle ever going to show you the actual shape?

 

How about some shots from this angle to make you understand:

If you still can't see the difference then I can't really help you.

It make no different at all , F-18 has bigger lerx as stated earlier , however their body is equally boxy , in fact F-18E is arguably has more boxy body

another advantages of F-35 is it's negative stability design while F-18E isnt

 

There's nothing particularly more draggy about the F-18's wing other than the fact that its longer, so I'm not sure what you're talking about here. With pylons of course it becomes more draggy, but the same applies to the F-35.

If you believe it has more lift then it will also has more drag , there no way around it

 

 

Thing is that in certain roles those bags will be dropped upon contact, or not carried from the start at all. It is in these roles that the F-35 will likely struggle by comparison, at least in traditional WVR combat.

For example if F-35 on 100% fuel can reach combat distance equal F-18 with 3 bags , let say they meet somewhere 600 km from their base , if the F-18 dropped it's fuel tanks and left with 100% internal fuel , the F-35 will be left with much smaller percentages of internal fuel ( may be around 50-60% ) , and that gonna changes it's T/W and wing loading significantly

[garrya]

Wasn't there a Lockheed report some years back that put the F-35A's sustained load factor at ~4.9 G's at Mach 0.8 at 15 kft? This whilst armed with two AMRAAMs internally.

 

If this is at all indicative of the current iterations' performance then that would mean its STR is little better if at all than that of an F-4 Phantom.

 

F-16C Block 50, Altittude = 15000 feet, Speed = M0,8:

 

weight = 22000lbs = 218 kg fuel (6% of total internal fuel capacity) => sustained 6,3Gs with Drag index = 0.

weight =26000lbs = 2032 kg fuel (63%) => sustained 5,3Gs with DI=0, 5,1Gs with DI=0, 5,2Gs with Drag index = 21.

weight = 28500lbs = 3227 kg fuel (100%) ==> sustained 4,8Gs with DI =0, 4,4Gs with DI=50, 4,6Gs with Drag index = 21.

there was no information about how much fuel or weapon the F-35 carry It will definately include two AAMs (as B variant has no gun, there is no point in giving it a "key performance figure" unarmed. Quite possibly, it will include 4 AAMs.Logically, KPP of F-35 will at least involve 50% fuel, and judging how other KPP is given to other aircraft, it is quite possibly 60%, to include reserve fuel into equation.

I assume F-35's specific range is consistent with its wing area and thrust increase, ballpark around 50%.

Then, there are 4 possibilities;

 

Possibility #1: F-35 achieved 4,6Gs with 60% fuel and 2 AAMs. This translates to same maneuverability, but fuel for longer range than F-16 with full internal fuel. For same range, F-35 needs less fuel, less weight. This translates to better maneuverability.

Possibility #2: F-35 achieved 4,6Gs with 50% fuel and 2 AAMs. With this fuel, F-35 can match range of F-16 with only 88% internal fuel. This means, F-35 is slightly inferior to F-16 (by 0,1Gs).

Possibility #3: F-35 achieved 4,6Gs with 50% fuel and 4 AAMs. Then you would have to subtract some 304 kg from fuel of F-16 , and add 8 to drag index, to compare it with equal grounds to F-35's KPP. Then F-35 will have better maneuverability for same range.

Possibility #4: F-35 achieved 4,6Gs with 60% fuel and 4 AAMs. Then, this translates to better maneuverability with fuel for better range. Translates to A LOT better maneuverability when fueled for same range.

Edited March 9, 2016 by garrya

[NineLine]

Wasn't there a Lockheed report some years back that put the F-35A's sustained load factor at ~4.9 G's at Mach 0.8 at 15 kft? This whilst armed with two AMRAAMs internally.

 

If this is at all indicative of the current iterations' performance then that would mean its STR is little better if at all than that of an F-4 Phantom.

 

Sounds like an imaginary report to me ;)

[Cunctator]

Wouldn't the F-35C have to fill that role for the U.S. Navy? While we are speaking of roles, will there be F-35's that are designated as tankers like we see now with the Super Hornet?

 

The Navy is looking at using the V-22 for its tanker needs going forward if I recall correctly.

 

The Navy has just started to develop an UAV tanker to free up its fighters from that duty. The Carrier-Based Aerial-Refueling System (CBARS).

Edited March 9, 2016 by Cunctator

[Sweep]

Sounds like an imaginary report to me ;)

 

I've heard that figure thrown around before.

 

The M=0.8 and the aircraft load are the assumptions, IIRC...

[Hummingbird]

It make no different at all , F-18 has bigger lerx as stated earlier , however their body is equally boxy , in fact F-18E is arguably has more boxy body

 

That's not what I see. The F-35's entire fuselage is boxy, by comparison at least large parts of the F-18's fuselage seem to be better optimized for lift.

 

If you believe it has more lift then it will also has more drag , there no way around it

 

That's not what we were talking about, we were talking about parasitic drag.

 

But since you want to talk about lift induced drag an aircraft with a lower W/L won't have to generate the same CL and therefore Cdi to achieve the same load factor, i.e. it will be less draggy in turns.

 

For example if F-35 on 100% fuel can reach combat distance equal F-18 with 3 bags , let say they meet somewhere 600 km from their base , if the F-18 dropped it's fuel tanks and left with 100% internal fuel , the F-35 will be left with much smaller percentages of internal fuel ( may be around 50-60% ) , and that gonna changes it's T/W and wing loading significantly

 

Depends on what model of F-18 we're talking about, the F/A-18E features a large enough internal fuel capacity that for most missions it usually only needs a single centerline fuel tank.

 

Internal fuel capacities:

F-35A = 18,498 lbs

F/A-18E = 14,400 lbs

F/A-18C = 10,860 lbs

 

With one std. 480 gal centerline fuel tank the F/A-18E carries an additional 3,276 lbs of fuel bringing its total up to 17,676 lbs.

[probad]

That's not what I see. The F-35's entire fuselage is boxy, by comparison at least large parts of the F-18's fuselage seem to be better optimized for lift.

 

Can you elaborate on how this works? I must be blind because for the life me I cannot see all that lift going on!