Super Hornet strikes again ...

[tflash]

JSOW C-1 against ships.

 

http://www.sacbee.com/2012/08/21/4744000/raytheon-us-navy-begin-jsow-c.html

 

Another string on its bow. At this pace, by the time the F-35C can catch a wire, the Super Hornet will be able to do what? Fly underwater? Refuel an aircraft carrier? Visualize a stealth plane in 3D?

[marcos]

I'm not really seeing anything special or new in this except the mid-course update which is only new to bombs. Bomb will get shot out of the air by a ship with half decent defences anyway.

[joey45]

Better integration into JSF.

[Speed]

I know at least one thing that the F-35C will be able to do that the F/A-18E can never hope to match: cost 200+ million each!

 

Joking aside, I don't know how you expect the F/A-18E to be able to ever be stealthy, supercruise, have the incredible sensors suite and sensors fusion of the F-35, etc :thumbup:

[aaron886]

JSOW is hardly a bomb anymore, more like a small cruise missile...! FWIW, mid-course weapon updates are nothing new. It would however be impressive to see that feature introduced to the JDAM tailkit... JDAM as a live-tracking weapon? Scary.

[Pyroflash]

I would love to see a mid-course update JDAM, but I wonder if such a thing would replace LGB's or not.

 

Also, I didn't know that the F-35 had supercruise. I thought that was only the F-22A.

[aaron886]

Also, I didn't know that the F-35 had supercruise. I thought that was only the F-22A.

 

Always did.

[MudRat02]

F-35 can probably supercruise like most of the other jets out there that can (except the Raptor): without any external stores and at high altitude. There was a Mirage III prototype that could supercruise back in the 60's at around Mach 1.3 by memory, but once again with its usual combat loadout it wouldn't.

[Speed]

Also, I didn't know that the F-35 had supercruise. I thought that was only the F-22A.

 

Yea, maybe you're right.

[marcos]

Also, I didn't know that the F-35 had supercruise. I thought that was only the F-22A.

Over 30,000lbf of dry thrust, I don't see why not, even with internal weapons. Based on dry thrust-to-weight and low drag internal weapon stowage it's highly likely. Half decent cannon for strafing too.

 

The first Lightning was able to supercruise at Mach 1.22 back in 1954 - the first fighter to achieve such a feat. Later version could go even faster on dry thrust. It was also able to climb at 50,000ft/min and break the sound barrier in a vertical climb back in the '50s!

Edited August 23, 2012 by marcos

[aaron886]

The first Lightning

 

P-38.

[amalahama]

Over 30,000lbf of dry thrust, I don't see why not, even with internal weapons. Based on dry thrust-to-weight and low drag internal weapon stowage it's highly likely. Half decent cannon for strafing too.

 

The first Lightning was able to supercruise at Mach 1.22 back in 1954 - the first fighter to achieve such a feat. Later version could go even faster on dry thrust. It was also able to climb at 50,000ft/min and break the sound barrier in a vertical climb back in the '50s!

 

F-35 has a very small wing area, so wing load will be high for sure. That means lot of induced drag. And induced drag goes with the square of mass!

 

I really doubt F-35 has supercruise capability, it's not a matter of "how big" your engine is, it's also how good your aerodynamics are, and the shobby F-35 doesn't have the sharpness and styliness of an Eurofighter or Raptor, sorry.

 

Regards!

[Griffin]

Does the F-35 supercruise?

No, neither the F135 or F136 engines were designed to supercruise.

 

http://www.jsf.mil/contact/con_faqs.htm

 

Found via Wikipedia. :)

[marcos]

http://www.jsf.mil/contact/con_faqs.htm

 

Found via Wikipedia. :)

Neither were the Typhoon engines but they still do, anywhere up to Mach 1.5 depending on load.

[marcos]

F-35 has a very small wing area, so wing load will be high for sure. That means lot of induced drag. And induced drag goes with the square of mass!

 

I really doubt F-35 has supercruise capability, it's not a matter of "how big" your engine is, it's also how good your aerodynamics are, and the shobby F-35 doesn't have the sharpness and styliness of an Eurofighter or Raptor, sorry.

 

Regards!

The first lightning didn't exactly have massive wings either.

 

The induced drag coefficient only forms part of overall drag coefficient and is partially offset by the fact that smaller areas mean less drag, since Drag = 0.5*Cd*Density*V^2

 

I have done calculations for the F-22 and F-35 at Mach 1.0 at 11000m altitude (Density = 0.365kg/m^3), using k = 0.2 and Cdo = 0.015, where:

 

Cd = Cdo + (k*Cl^2)

 

Cl = (2*Weight)/(Density*Wing Area*V^2)

 

Drag = 0.5*Cd*Density*V^2

 

I have used 23,500lbf dry thrust per engine for the F-22 dry and calculated for the F-35 using 34,000lbf. The Raptor's Weight is 29300kg and the F-35's is 22,470kg.

 

The Thrust/Drag ratios at Mach 1.0 at 11000m were as follows:

 

F-22 - 5.964

 

F-35 - 6.133 (STOVL), 5.051 (Variant with 28,000lbf)

 

Now given that the F-22 can allegedly supercruise at Mach 1.8+, it seems clear that there is nothing to suggest that the F-35 can't supercruise. Of course these are only rudimentary calculations and the ability of the engine to produce thrust at a given speed is also important but given that the F135 is based on the F119 core, the similarities in thrust vs speed profile will be strong.

Edited August 23, 2012 by marcos

[amalahama]

The first lightning didn't exactly have massive wings either.

 

The induced drag coefficient only forms part of overall drag coefficient and is partially offset by the fact that smaller areas mean less drag, since Drag = 0.5*Cd*Density*V^2

 

I have done calculations for the F-22 and F-35 at Mach 1.0 at 11000m altitude (Density = 0.365kg/m^3), using k = 0.2 and Cdo = 0.015, where:

 

Cd = Cdo + (0.5*k*Cl^2)

 

Cl = (2*Weight)/(Density*Wing Area*V^2)

 

Drag = 0.5*Cd*Density*V^2

 

I have used 23,500lbf dry thrust per engine for the F-22 dry and calculated for the F-35 using 34,000lbf. The Raptor's Weight is 29300kg and the F-35's is 22,470kg.

 

The Thrust/Drag ratios at Mach 1.0 at 11000m were as follows:

 

F-22 - 2.515

 

F-35 - 2.594 (STOVL), 2.137 (Variant with 28,000lbf)

 

Now given that the F-22 can allegedly supercruise at Mach 1.8+, it seems clear that there is nothing to suggest that the F-35 can't supercruise. Of course these are only rudimentary calculations and the ability of the engine to produce thrust at a given speed is also important but given that the F135 is based on the F119 core, the similarities in thrust vs speed profile will be strong.

 

Your calculation is wrong because, to begin with, your drag units are not consistent. You miss Reference Area there.

 

Anyway, Cd is defined as:

 

Cd=Cd0 + k*CL^2 (there is no 1/2 in the eq)

 

There is no huge differences on Cd0 for "well designed" fighters. However, considering same speed and height, CL is proportional to wing load, therefore for fighters with high wing load in cruise (that's it, heavy with small wing), drag raise very quickly. Aerodynamic polars are quadratic, I'm sure you know...

 

And F-35A has a tiny wing, however it's even heavier than an Eurofighter.

 

So though F-35 would have had a nice T/W ratio (which it doesn't), you cant miss the point that its small wing provide lot of drag, more than equivalent standard european fighters (which all enjoy of large delta wing prepared for supersonic).

 

And talking about parasite drag, don't miss either that F-35 is larger because has to carry stores inside, so "washed" area is larger, and also that frontal area is quite large if you compare with wing span, because his relatively-high-bypass engine is very big.

 

I don't doubt F-35 will be a wonderful attack aircraft, but I really doubt it can do any harm to pure-fighter designs, specially in dogfighters; hell even in BVR a Su-35 can enjoy better kinematic properties, launching its ordinance faster and higher than F-35 can.

 

Regards!

Edited August 23, 2012 by amalahama

[Pilotasso]

Where you guys getting the info the F-35 can supercruise? (MACH 1.5, not 1.0).

[marcos]

Your calculation is wrong because, to begin with, your drag units are not consistent. You miss Reference Area there.

No I use the wing area as a rough estimate for reference area. This is common practice when estimating the performance of enemy aircraft, where figures aren't readily available.

 

Anyway, Cd is defined as:

 

Cd=Cd0 + k*CL^2 (there is no 1/2 in the eq)

Wrote it down wrong but did the calculation right. Stick in the figures and see.;)

 

 

There is no huge differences on Cd0 for "well designed" fighters. However, considering same speed and height, CL is proportional to wing load, therefore for fighters with high wing load in cruise (that's it, heavy with small wing), drag raise very quickly. Aerodynamic polars are quadratic, I'm sure you know...

Actually wing loading is not terribly significant during cruise and climb because the aircraft is only loaded at 1.0g. It increases Cl and kCl^2 but the smaller wing area also reduces the reference area in the overall drag calculation and the kCl^2 term in level cruise is small relative to Cdo. During high-g turns it is far more significant because Cl increases greatly.

 

And F-35A has a tiny wing, however it's even heavier than an Eurofighter.

It also has more thrust than the Typhoon and, as mentioned, Cl has little impact during level cruise. Do a 9g turn however and the Typhoon's drag is increased far less than the F-35 or F-22's or any other aircraft bar the Rafale and the now defunct YF-23 with it's massive 88m^2 wing area and sub F-22 weight.

 

 

So though F-35 would have had a nice T/W ratio (which it doesn't), you cant miss the point that its small wing provide lot of drag, more than equivalent standard european fighters (which all enjoy of large delta wing prepared for supersonic).

As mentioned the wing loading has little impact during level flight since kCl^2 is small relative to Cdo when loaded at 1g and smaller wings also lower the drag reference area used. You have to be careful when assessing T/W ratio since some of the figures are clearly wrong given that the F-35 has performed loaded VTOL during testing. I suspect some of the figures come from the same place that suggest the F-35's engines are not designed to supercruise despite being based on the F119's core, which is designed for supercruise. Did the engineers take a core that can supercruise and decide to make it not supercruise? Seems unlikely.

 

And talking about parasite drag, don't miss either that F-35 is larger because has to carry stores inside, so "washed" area is larger, and also that frontal area is quite large if you compare with wing span, because his relatively-high-bypass engine is very big.

The F-22 also carries stores internally and the bays are about the same size plus the F-22 weighs 7-9tons more depending where you look.

 

I don't doubt F-35 will be a wonderful attack aircraft, but I really doubt it can do any harm to pure-fighter designs, specially in dogfighters; hell even in BVR a Su-35 can enjoy better kinematic properties, launching its ordinance faster and higher than F-35 can.

 

Regards!

I think you're right. Wing loading will have a bigger impact on drag during high-g manoeuvres relative to the Typhoon/F-22/Rafale but when you compare wing loading, based on empty weights, with that of a MiG-35 or Su-35, you can see that they are very close, so it will still be a very competent dog-fighter with some very handy reverse thrust and hover tactics.

Edited August 23, 2012 by marcos

[amalahama]

...

 

Well OK but again also you have to be careful with the figures you are using. For example, I've seen you have used "Loaded Weight" from wiki, but we don't know what "loaded weight" means (full fuel? AA configuration? or clean?) so I've used empty+full fuel and I've calculated both wing load in that situation

 

F-22=357.5 Kg/m2

F-35A=507.7 Kg/m2 !!!!

 

+42% over F-22 Wing load!. Now, taken the same empty+full fuel weight and advertised full mil thrust, T/W for both are:

 

F-22=0.745

F-35A=0.5765!

 

Tada! Here you can see how F-35 lay far behind F-22 performance.

 

Actually wing loading is not terribly significant during cruise and climb because the aircraft is only loaded at 1.0g. It increases Cl and kCl^2 but the smaller wing area also reduces the reference area in the overall drag calculation and the kCl^2 term in level cruise is small relative to Cdo. During high-g turns it is far more significant because Cl increases greatly.

 

Cruise drag it doesn't have anything to do with g's, but with Alfa. And depending on how big your wing is, and how heavy your plane is, alfa will be more or less. And again, Cd goes with the square of AoA.

 

Regards!

Edited August 23, 2012 by amalahama

[Pilotasso]

wingloading doesnt tell you the whole story, Compare F-15 VS F16, The F-16 is more agile at low to medium altitudes and it has higher wing loading, the situation is reversed at high altitudes.

 

When a plane has a high wing load it also means usually they have smaller wings, and that entails less direct drag for forward motion, at higher altitude, its the other way around, AOA induced drag overcomes profile drag due to thinner air.

[marcos]

Well OK but again also you have to be careful with the figures you are using. For example, I've seen you have used "Loaded Weight" from wiki, but we don't know what "loaded weight" means (full fuel? AA configuration? or clean?) so I've used empty+full fuel and I've calculated both wing load in that situation

 

F-22=357.5 Kg/m2

F-35A=507.7 Kg/m2 !!!!

 

+42% over F-22 Wing load!. Now, taken the same empty+full fuel weight and advertised full mil thrust, T/W for both are:

 

F-22=0.745

F-35A=0.5765!

 

Tada! Here you can see how F-35 lay far behind F-22 performance.

 

 

 

Cruise drag it doesn't have anything to do with g's, but with Alfa. And depending on how big your wing is, and how heavy your plane is, alfa will be more or less. And again, Cd goes with the square of AoA.

 

Regards!

Those are some very incomplete calculations with respect to drag. I used the 49,000lb weight for my calcs but I believe that that wiki page has been changed several times and that ~44,000lb was the original figure, just as 34,000lbf is the actual dry thrust:

 

http://www.airvectors.net/avf35.html

http://www.kerryplowright.com/aircraft/F35_Joint_Strike_fighter.htm

http://myyellowcity.blogspot.co.uk/2011/01/india-usf-35-lightning-ii-jet.html

 

You can't just work out wing loading and T/W and assume that tells you the full story. Follow my calculations through after converting everything the SI units (Newtons, kg, metres/s) and you will see things as they actually are rather than part of the picture.

 

Drag reference area:

 

F-22 - 78.13m^2

F-35 - 42.7m^2

 

Tada F-22 has an 1.83 times larger drag reference area and the F-35 only has a 1.40 times larger wing loading. Yes that gets squared to 1.96 but kCl^2 is less than Cdo so forms less than a half of Cd which gets times by the 1.83.

 

It's not too unreasonable to think that the F-35 can supercruise given that it uses the same engine core as the F-22 with revised components to increase mass-flow rate AND given that the first fighter to supercruise first flew 58 years ago and was called Lightning I. Supercruise is not new, it's just that the F-22 can do it faster than most.

Edited August 23, 2012 by marcos

[amalahama]

Ok, I agree with your calculation marcos, yet I bet at last absolute drag from F-22 and F-35 are not as different as their drag reference area. Being F-35 wing area almost half F-22 wing area, but weighing just 30% less (talking about empty mass here), cruise AoA must be higher, and in high transonic regime drag polar gets even steeper than quadratic progression. But it's fine, I give in.

 

But still you have to face three facts: First we haven't talked about wave drag yet, and it has an strong dependency on AoA; T/W ratio lay below F-22 and finally F-135 bypass ratio is slightly higher than F-119 (I remember having read this somewhere, but I can't recall how big it is), which lead to worse performance at high speed (because high bypass ratio turbofan squeeze each fuel drop in subsonic, but performs badly in supersonic)

 

So yet I'm quite doubtful about F-35 supercruise capability, it's not just a matter of engine being prepared for that, you also stated that old aircraft like Lighting could do it in the 60's, but Lighting performance was far better than F-35 (don't ask for range, though)

 

Regards!

Edited August 23, 2012 by amalahama

[aaron886]

Lighting performance was far better than F-35 (don't ask for range, though)

 

Don't make unsubstantiated claims... they ruin a discussion. You have no idea what the pertinent performance figures of the F-35 are. :(

[marcos]

Ok, I agree with your calculation marcos, yet I bet at last absolute drag from F-22 and F-35 are not as different as their drag reference area. Being F-35 wing area almost half F-22 wing area, but weighing just 30% less (talking about empty mass here), cruise AoA must be higher, and in high transonic regime drag polar gets even steeper than quadratic progression. But it's fine, I give in.

Well work both percentages in the same direction. The wing area is 45% less and the empty weight is 32.5% less (13300kg vs 19700kg).

 

But still you have to face three facts: First we haven't talked about wave drag yet, and it has an strong dependency on AoA; T/W ratio lay below F-22 and finally F-135 bypass ratio is slightly higher than F-119 (I remember having read this somewhere, but I can't recall how big it is), which lead to worse performance at high speed (because high bypass ratio turbofan squeeze each fuel drop in subsonic, but performs badly in supersonic)

The value of Cdo is increasing for both aircraft in the transonic regime but the value of k remains steady until Mach 1.2 where it increases for both aircraft. Wave drag is proportional to the length of the wing. The longer the wing the longer the shock wave. It also increases with the square of the thickness/chord ratio. Wing sweep and good, steadily changing thickness/chord profiles help reduce it. As a general rule wave drag is minimised by ensuring that the variation in the cross-sectional area of the aircraft along the line of flight in the plane perpendicular to flight varies by as little as possible, in as smooth a fashion as possible. Only one component of the wave drag coefficient is dependent on lift, the other, supersonic volume dependent wave drag, is not, therefore we again have some drag contributors dependent on lift and some that are not and the ones that are dependent are again offset by the lower drag reference area of the F-35 during steady 1.0g flight. But, in this case, volume dependent wave drag will be a larger contribution for the aircraft with the larger volume.

 

So yet I'm quite doubtful about F-35 supercruise capability, it's not just a matter of engine being prepared for that, you also stated that old aircraft like Lighting could do it in the 60's, but Lighting performance was far better than F-35 (don't ask for range, though)

 

Regards!

Old aircarft like the Lightning did it in 1954 and hit Mach 2+ when F-86s and F-84s were still pratting about in the skies at subsonic speeds. It was so fast for the era that the first Soviet bomber it intercepted was relieved to see it because the closure speed had lead them to believe it was a SAM and it was made by a washing machine manufacturer. As regards range, an ex-pilot believed he could empty one inside an hour but at 1400+mph that's a long way. Add it to your DCS wishlist!!!

 

I have no doubt about the F-35's supercruise ability whatsoever. I'm prepared to bet money on it. I don't even know why people think supercruise is special these days.

Edited August 23, 2012 by marcos

[tflash]

Very interesting read, thanks, I should change the subject of the thread :=)

 

Coming back to my original post as an intermezzo, I think the new thing is that a second Hornet takes over the in-flight command of the JSOW. That offers some nice tactical possibilities.

 

We should also understand that while the Super Hornet, building on 4th generation technology, matures at an amazing pace and now sports an incredible long list of combat tested weapons. It also has a very performant data bus and strong networked communications. When the F-35C will start to be operational around 2016, it will not at all be with a complete suite of weapons, most probably with only a couple of A2G weapons.

 

I guess F-35 will only very slowly expand its mission portfolio, look at the F-22. That means an F-35 being able to do most Super Hornet missions is something for the late 2020's. By then Super Hornet will have had a midlife update and certainly have better integrated avionics than today. It will of course never be a stealth aircraft.