The F-35 Thread

[SkateZilla]

Google Earth isnt exactly "realtime"

 

My Fathers van that we sold shortly after his passing is still sitting in our drivway on the Goog.

 

I didnt realize my yard was so green....

[cichlidfan]

I am well aware of that Skates. If GE had dated that image, I would have provided it.

 

The imagery of my house is from last April.

 

Btw, I was handling satellite imagery data sets, as part of my job, over 20 years ago. I have a pretty good handle on how it works.

Edited March 10, 2016 by cichlidfan

[Exorcet]

I don't really dig aerodynamics so can you please explain how this design with a duct in the LERX is generating additional lift?

 

I found this:

 

[ame]http://history.nasa.gov/monograph19.pdf[/ame]

 

PDF page 49 under Cruise Drag

 

I did not remember correctly. The slots were actually draggy on the YF-17 and filling them was recommended. The negative impact of this was minimal. I'm not sure what the impact of the remaining small slots are on the F/A-18. They might still help reduce adverse pressure gradient and delay vortex breakdown (which you can see on PDF page 52).

 

 

 

 

 

If we look at this like an airfoil it is how the leading edge is shaped which causes issues IMO. The first thing the air meets on the F-35 are two open intakes, on an airfoil this means a loss in lift. On the F-18 the air is instead first met by a sharp leading edge, flat on the bottom and curved on the top. The bottom airstream is then more smoothly redirected about halfway down the fuselage.

I wouldn't know what's going on up there exactly without CFD or flow visualization. I can see what you're saying and the inlets are not going to be the best leading edge, but as long as flow comes in roughly parallel to the inlet surfaces it should make a decent wing. The underside of the F-35 being fairly wide and flat means flow will want to go lengthwise rather than spanwise, which is a big efficiency gain. The flow is also already going to be directed by the nose to some degree, and if LM has done their job it's going to benefit the inlets as much as possible.

Edited March 10, 2016 by Exorcet

[garrya]

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.

Now it just a matter of subjective opinions , you may think F-18 fuselage look less boxy compare to F-35 , while me and others disagree . Unless anyone here can put the 3D model of them in a wind tunnel , i dont think it is actually a valid speculation to say which body is better optimized for lift

 

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.

I dont think F-35 have higher wing loading than F-18 when they are fueled to fly the same distance to be honest , the main reason for f-35 high wing load come from the huge amount of fuel that it carry.

and F-35 also have more powerful engine

 

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.

F-18E is even more draggy than F-18C and carry external fuel tank externally cause significant increase in drag and RCS too

[garrya]

Have they demonstrated any version of this? Are they going to soon? The answer to both is no.

 

Conformal fuel tanks are real and being used on aircraft, lasers are not. There is no comparison.

 

actually there are several version of air based laser already

http://defense-update.com/20080813_atl-c-130.html

http://beforeitsnews.com/alternative/2014/09/lockheed-martin-successfully-tests-new-air-based-laser-turret-3030678.html

[Hummingbird]

actually there are several version of air based laser already

http://defense-update.com/20080813_atl-c-130.html

http://beforeitsnews.com/alternative/2014/09/lockheed-martin-successfully-tests-new-air-based-laser-turret-3030678.html

 

I don't think they actually mounted any lasers there garrya, they've just tested the platform.

 

Furthermore those are rather large aircraft, not fighters. I don't think we will see lasers on fighters anytime soon as they require a lot of power to function, esp. if they are supposed to be powerful enough to shoot down stuff.

 

Either way it is not a valid comparison to conformal fuel tanks at all as they are by comparison very real, have been demonstrated and can be made available in no time.

 

Edited March 11, 2016 by Hummingbird

[Tirak]

I don't think they actually mounted any lasers there garrya, they've just tested the platform.

 

Furthermore those are rather large aircraft, not fighters. I don't think we will see lasers on fighters anytime soon as they require a lot of power to function, esp. if they are supposed to be powerful enough to shoot down stuff.

 

Either way it is not a valid comparison to conformal fuel tanks at all as they are by comparison very real, have been demonstrated and can be made available in no time.

 

 

1. Yes they have mounted and used those lasers. Furthermore, directly from that research, laser weaponry is being mounted on US Navy ships to operate in the point defense role.

 

2. I don't know if you know this, but the pic you linked is the Boeing Demonstrator aircraft. It is not in active service with the military of any nation. It is not a full production aircraft as no one has bought it. Allow me to reiterate this loud and clear since you have some difficulty understanding this.

 

THERE IS NO F-18 HORNET IN THE INVENTORY OF ANY NATION'S MILITARY THAT USES CONFORMAL FUEL TANKS.

 

 

[SkateZilla]

1. Yes they have mounted and used those lasers. Furthermore, directly from that research, laser weaponry is being mounted on US Navy ships to operate in the point defense role.

 

2. I don't know if you know this, but the pic you linked is the Boeing Demonstrator aircraft. It is not in active service with the military of any nation. It is not a full production aircraft as no one has bought it. Allow me to reiterate this loud and clear since you have some difficulty understanding this.

 

THERE IS NO F-18 HORNET IN THE INVENTORY OF ANY NATION'S MILITARY THAT USES CONFORMAL FUEL TANKS.

 

 

 

 

 

Super Hornet Block III uses CFT and IRST Centerline Pod.

 

Both of which have already been Approved by DoD

Edited March 11, 2016 by SkateZilla

[Hummingbird]

1. Yes they have mounted and used those lasers. Furthermore, directly from that research, laser weaponry is being mounted on US Navy ships to operate in the point defense role.

 

2. I don't know if you know this, but the pic you linked is the Boeing Demonstrator aircraft. It is not in active service with the military of any nation. It is not a full production aircraft as no one has bought it. Allow me to reiterate this loud and clear since you have some difficulty understanding this.

 

THERE IS NO F-18 HORNET IN THE INVENTORY OF ANY NATION'S MILITARY THAT USES CONFORMAL FUEL TANKS.

 

 

 

You have trouble reading I see...

 

Lasers will not be mounted on fighters in the forseeable future, conformal fuel tanks will. Furthermore the CFT's offered by Boeing are also an option for foreign buyers, i.o.w. they are a ready & available design.

 

F-18's armed with lasers is a ridiculous comparison, I'm sorry but it is.

[Tirak]

Super Hornet Block III uses CFT and IRST Centerline Pod.

 

Both of which have already been Approved by DoD

 

The only Hornets that I know of on the DoD's purchase list, was just under 20 Growlers, which was part of the unfunded mandate. Boeing's been talking about the "Ultra Hornet" for years, got any figures or sources indicating the Navy is actually buying them?

 

@Hummingbird: Frankly it's the same comparison. The F-18 in service today does not have CFTs. The F-35 in service today does not have lasers. CFTs have been demonstrated on experimental testing aircraft. Lasers have been demonstrated on experimental testing aircraft. Neither are pertinent to a comparison of the F-18 and F-35 since neither of them are actually used by a military fielding the aircraft.

[SkateZilla]

The Navy Approved Productoon of the IRST21 Centerline Pod in January 2015., 1st Delivery was 6 Units back in Like March 2015.

 

They arent Buying New F-18E/F, they are upgrading the current fleet.

Edited March 11, 2016 by SkateZilla

[garrya]

The Navy Approved Productoon of the IRST21 Centerline Pod in January 2015., 1st Delivery was 6 Units back in Like March 2015.

 

They arent Buying New F-18E/F, they are upgrading the current fleet.

 

i dont think they approved of buying CFT for F-18

[SkateZilla]

Block III:

Conformal Fuel Tanks, EPE,EWP, IRST, Single Display Cockpit Panel, MWS,

 

CFTs Would Reduce Drag, Increase Range, and Increase Bring Back, Free Up Pylons for Additional Stores if Needed.

 

However, No CFT's have been officially purchased, and the Proto's weight twice as much as the production tanks would, so they wont be buying the proto's either.

 

the CFT's do cause Tran-sonic distortion...

[Tirak]

Block III:

Conformal Fuel Tanks, EPE,EWP, IRST, Single Display Cockpit Panel, MWS,

 

CFTs Would Reduce Drag, Increase Range, and Increase Bring Back, Free Up Pylons for Additional Stores if Needed.

 

However, No CFT's have been officially purchased, and the Proto's weight twice as much as the production tanks would, so they wont be buying the proto's either.

 

the CFT's do cause Tran-sonic distortion...

 

So No Block III "Ultra" Hornet, no CFTs. Got it.

[SkateZilla]

Navy will be getting IRST and EPE,

 

the IRST will allow Longer Range AIM-9X Deployment, which would also be immune to enemy jamming.

 

EPE will give Additional thrust and better burn.

[Hummingbird]

@Hummingbird: Frankly it's the same comparison. The F-18 in service today does not have CFTs. The F-35 in service today does not have lasers. CFTs have been demonstrated on experimental testing aircraft. Lasers have been demonstrated on experimental testing aircraft. Neither are pertinent to a comparison of the F-18 and F-35 since neither of them are actually used by a military fielding the aircraft.

 

Lasers have not been tested nor even suggested for the F-18 or F-35 now have they? There's the difference: One is a realistic and proven feature that the aircraft is ready to operate with, the other is fantasy.

 

Conformal fuel tanks are atm in use on both the F-16 and F-15 and they are ready for use with the F-18, meanwhile no fighter in the world carries a laser and there are no plans for any fighter carrying one in the foreseeable future either.

[Tirak]

Lasers have not been tested nor even suggested for the F-18 or F-35 now have they? There's the difference: One is a realistic and proven feature that the aircraft is ready to operate with, the other is fantasy.

 

Conformal fuel tanks are atm in use on both the F-16 and F-15 and they are ready for use with the F-18, meanwhile no fighter in the world carries a laser and there are no plans for any fighter carrying one in the foreseeable future either.

 

Lasers have been proposed for the F-35 and Darpa is already working on integration.

 

CFTs are not used on the F-18s, I don't care about potentialities, they are flat out not used on them. Period. Any discussion of including them in a comparison against the F-35 is as disingenuous as me attempting to assert Lasers as a viable weapon for the F-35. Hyperbole? A bit, but hyperbole makes a hell of a point.

[Dudikoff]

By re-directing a portion of Intake Air both up and over the body of the fuselage, and across the bottom, the fuselage becomes a lift surface.

 

I can understand the bottom part, but I don't understand how directing the air up and through these small ducts actually increases lift rather than decreasing it?

 

I think in the case of the YF-17 there were instability issues without the duct. Basically the LERX was too big/not shaped properly and air couldn't smoothly flow along the top. I'm not sure if I'm remembering this correctly though and I'll need to look it up.

 

That makes more sense, I'll check the PDF you posted, thanks for the info.

[garrya]

Navy will be getting IRST and EPE,

 

the IRST will allow Longer Range AIM-9X Deployment, which would also be immune to enemy jamming.

 

EPE will give Additional thrust and better burn.

 

as far as i know, they only getting the IRST21 pod and that it, no plan to buy EPE engine , even if they decided to buy new engine, the EDE would be more likely to get the contract

[garrya]

Conformal fuel tanks are atm in use on both the F-16 and F-15 and they are ready for use with the F-18, meanwhile no fighter in the world carries a laser and there are no plans for any fighter carrying one in the foreseeable future either.

 

while it true that CFTs on F-18 is easier to make than Laser on F-35, at the moment F-35 program have much higher priority compare to F-18, most of the upgrade would be centered around it, i believe that it will even get the Advent engine before F-18 get their engine upgrades

[SkateZilla]

All I want is friggen 35s with friggen laser beams attached to their heads... lol

[Hummingbird]

All I want is friggen 35s with friggen laser beams attached to their heads... lol

 

*Pew pew!*

 

[Hummingbird]

I found this:

 

http://history.nasa.gov/monograph19.pdf

 

PDF page 49 under Cruise Drag

 

I did not remember correctly. The slots were actually draggy on the YF-17 and filling them was recommended. The negative impact of this was minimal. I'm not sure what the impact of the remaining small slots are on the F/A-18. They might still help reduce adverse pressure gradient and delay vortex breakdown (which you can see on PDF page 52).

 

Yes for the F/A-18 the large forward slots on the YF-17's LERX were removed, which is understandable, the small duct at the back wasn't however as it probably proved critical to body lift and perhaps reenergizing the LERX vortex. In addition to this the LERX on the F/A-18 were slightly enlarged.

 

YF-17:

Edited March 14, 2016 by Hummingbird

[SkateZilla]

So many differences between thenYF17 and F18A, lol

[Hummingbird]

So many differences between thenYF17 and F18A, lol

 

Yes there were quite a few changes made, incl.:

 

- New horizontal stabilizer planform

- Enlarged LERX

- Removal of foward gaps in LERX

- Refinement of nacelle bypass duct & splitter

- Dog-tooth wing

- reshaped fuselage nose section