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JSF B vs C

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vegita1220

User
Ok so the B is the VTOL Marine version, and the C is the Carrier modified version. Supposedly, C gives better range, low-speed handling, takeoff weight, etc. but is slightly larger.

Out of sheer curiosity...
are the B VTOL models going to be flying off carriers as the VMFA's still do? Or will they be limited to their amphib assault ships like the Tarawa class? If they stay on the big deck carriers, will they land conventionally or hook? If they're gonna VTOL on and off, why doesn't the Navy just go with the B as well? I assume it's b/c of other performance aspects of the C model...
It just seems a little...odd.
 
B

Brodie143

Registered User
B's are amphib only. C's are carrier only. I am not completely sure but I doubt the B has the arresting geat and landing gear required for carrier take offs and landings. B's eat up to much gas for Navy needs, ie can't carry as many big bombs and still have the same range and perfromance. B's should only replace the Harriers guys not the Hornets. VMFAs will stay with hornets for many years and then get old Super Hornets from the Navy after that.
 
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Rainman

*********
pilot
Well. ..I'm gonna shoot my mouth off on this one (mostly cause I've been drinkin).. alright. . well. . the Marines have no plans to buy SuperHornets in the next 10 years. ..so squash that one.

yeah. .B's will replace Harriers. . potentially some Hornet squadrons. .hard to say (no decision as of yet). . originally. .the MC was getting all Bravos. . then with the new carrier integration plan it was determined that we needed squadrons of Charlies as well for carrier work .. most jets have tailhooks but aren't designated for carrier traps/launch. .. so there's that. .. To my knowledge Navy has no plans to buy Bravos at this time. . ... ..Pool and a pond. . .pond would be good for you.
 
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kimphil

Registered User
I'm going to tread into territory that I know dangerously little about (like that's stopped me before).
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Because of the lift fan placed in the B model for SVTOL, it will have a shorter range (the A and C model replaces the lift fan with an extra fuel tank). The B model will also have no internal gun, instead relying on an external gun pod. The C model will have larger wings and a reinforced airframe and tailhook for carrier operations. But all versions should have approximately the same performance characteristics (with the B having a shorter unrefueled range).

I also read something interesting in a book at Barnes & Noble called Lockheed Stealth about the JSF. If I got this right, the JSF will have one of the most sophisticated radars in the fleet. Its radar could potentially allow any JSF to do double duty as an Electronic Warfare plane. (watch out EA-6B!)

Why doesn't the Navy use the B model? Probably politics. It would be hard for the Navy to justify big, expensive supercarriers if all their planes (and helos) could do short take-offs and vertical landings.

However, in defense of the Navy, carriers and arrested landings work. There's no compromise on the performance of the plane, or risking the development of unprecedented technology (ie the vertical lift fan) in their planes. So there! I want no flames from the Navy!
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Mongol General: ...Conan, what is best in life?
Conan: To crush your enemies, see them driven before you, and to hear the lamentation of the women!
Mongol General: That is good.
 
PU Grad

PU Grad

MAC flight user
pilot
See, the VTOL takes quite a bit more fuel than a conventional/catapult take-off. The other fun part is that for a VTOL the plane can't be loaded to the gills with fuel and weapons. (The fan just isn't strong enough to lift the same amount of weight that the Bravo could lift in a conventional take-off.)

This means that it is either going to have to skimp on weapons or fuel or maybe a combination of both. If it is skimping on the fuel than a tanker would be required in the air just to refuel the planes as they reach altitude. This would limit the number of combat planes the carrier would carry and add more tankers. Most of the capabilities of the VTOL is used in a manner halfway during the flight (in dangerous territories where only a small area to land can be found) and then when the plane is low on fuel landing back at base.

For this reason the Navy won't replace Hornets with the Bravo Configuration.


I know I have not posted much but this is the kind of training I am receiving (Engineer).

Kobyra

Edit: I seem to be using Engrish, it has been a long week.
 
K

kimphil

Registered User
No offense kobyra, but you don't know what you're talking about. You're correct about the performance sacrifices a VTOL plane would have to make. But the Marine Corps (and the Royal Navy) don't use VTOL planes. They use STOVL (got to get my acronyms right, got it wrong in my previous post). The "STO" for short take-off. With a short take-off (approximately 500 ft) the JSF B (as well as the Harrier) can go into combat with a full load of fuel and weapons, and it doesn't need a catapult to take-off. It can then return from its mission and land vertically.

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Mongol General: ...Conan, what is best in life?
Conan: To crush your enemies, see them driven before you, and to hear the lamentation of the women!
Mongol General: That is good.
 
JayManC

JayManC

Registered User
you guys are forgetting one major factor in the decision for the navy not to move to stovl jets.....CVX the next generation carriers... which OBTW are hideous (ive seen some of the specs) but that would be a major determinant of STOVL, more or less the navy wants range, theyd rathe rnot have to sit right off shore and get bombarded while conducting air ops/strike ops so that being said, conventional carrier launch/recovery is quite the selling point, which was on reason the F-22 didnt make it to the fleet

<insert something witty here:>
 
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kimphil

Registered User
If the Navy wants range it can dump the pilot and use UCAVs!
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Mongol General: ...Conan, what is best in life?
Conan: To crush your enemies, see them driven before you, and to hear the lamentation of the women!
Mongol General: That is good.
 
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farkle84

New Member
dump the pilot, then we are would all be out of a job or looking to go into another one. dont say that on this website. jk
 
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kimphil

Registered User
Sorry!
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Mongol General: ...Conan, what is best in life?
Conan: To crush your enemies, see them driven before you, and to hear the lamentation of the women!
Mongol General: That is good.
 
PU Grad

PU Grad

MAC flight user
pilot
"They use STOVL (got to get my acronyms right, got it wrong in my previous post). The "STO" for short take-off. With a short take-off (approximately 500 ft) the JSF B (as well as the Harrier) can go into combat with a full load of fuel and weapons, and it doesn't need a catapult to take-off. It can then return from its mission and land vertically."

Yes they use STOVL, but those aircraft are also able to VTOL. The longer take-off distance that can be used the larger the gross take-off weight. Basically the plane isn't using the full advantage of the airfoil to generate lift and the lift fan can't fully replace that lift. If you look at the gross take-off weight of the aircraft vs. the take-off distance it will look like this

Gross Weight = GW
Max Gross Weight = MGW
VTOL Gross Weight = VGW
distance = d

GW = (MGW) - (MGW - VGW)* e^(-d)

Not quite but it gives the general idea.


Just a random question when did I say that the Bravo could use a catapult or arresting wires to take-off or land, respectively.

I did make a comparison of an aircraft that uses Vertical take-off to a conventional take-off, I added in the catapult take-off for comparison to similar aircraft since the B can't do it, and since the catapult take-off is anything but conventional.

Kobyra

P.S. If you would like to debate this further I can. I like to subscribe to the KISS method while talking on forums. I do not have all of the specs on the JSF with me right now, they tend to be a bit classified. But I am sure I can show you some unclassified information for you that was publish in Aviation Week a couple of years back while the Lockheed and the Boeing versions were being compaired.
 
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kimphil

Registered User
Can't...resist...debating!
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Yes, the Harrier and F-35B (USMC JSF) can VTOL. That's great for airshows and impressing congressmen, but completely useless and unnecessary for combat. STOVL is the more practical solution.

I'm going to skip all the engineering geek-talk and concede that the Marine Corps version may have to make compromises in fuel/weapons that the AF and Navy versions won't. Will that render the USMC version less useful than the other versions? I seriously doubt that. When all is said and done, I'm going to assume that our mad rocket scientists will give all versions of the JSF comparable performance.

Just a random question, if a plane can operate from a ship with little, if any compromises to its range and potential missions without the use of a catapult or arresting wires, then why would we need supercarriers?

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Mongol General: ...Conan, what is best in life?
Conan: To crush your enemies, see them driven before you, and to hear the lamentation of the women!
Mongol General: That is good.
 
V

vegita1220

User
Oh goodie...I stirred up controversy.

Now to shoot my mouth off and get shot down by the real aviators here.

Kimphil...Please don't mention UCAVs...I'm not even close to flight school yet, and I wanna get in a cockpit before the damned computers take over.
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Now...more seriously, the C supposedly provides the BEST performance of the three. It has a significantly larger wing area, which is supposed to improve low speed handling, while also increasing the range by I believe 15%.

I brought up the Bravo on CVN thing b/c I know the Marines supposedly are not buying any Charlies...although that may not be the case. Maybe the Navy and Marines will trade a few. :)
But I figure the Bravo should have no prob operating off carriers, if helicopters can as well.
And the Bravo does compromise, supposedly. As mentioned, no internal gun, much decreased range. On the other hand, I'm sure Harrier pilots will be glad to have a plane which does the same while also giving them a better fighting chance against enemy a/c's.
 
K

kimphil

Registered User
Speculating about the future of naval aviation is fun! What do I see in my crystal ball? I see UCAVs! But let's not talk about that.
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There's no argument that a C model will have greater range than a B model. We can all agree on that.

The dispute centers on whether STOVL (not VTOL) further compromises the fuel/weapons load of the B model to such a degree that the Navy (and Marine Corps) would prefer the C model for CV operations. Since we don't know the precise performance of the B v. C, we can only speculate.

kobyra contends that the lift-fan of the B model can't generate enough lift in a short take-off to allow it to have the comparable gross weight of the C model. I'll concede that. However, if the B model could take off with, for example, 90 percent of the gross weight of the C, that might be more than adequate for most missions.

The point of contention is, how much does the B model sacrifice in terms of unrefueled range/payload v. the C model? And is this sacrifice enough to outweigh the advantages of the B v. C model? My guess, there's not much sacrifice, so there isn't a significant advantage to the C model.

However, I'm sure there are political motivations to having C models operate from CVs, so I'd have to agree with Rainman -- I see a future where the Marines would operate C models. (Did I mention I also see dead people?)
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Picture this scenario -- The USMC replaces all its Harriers and Hornets with the B model JSF. Imagine the B model operating alongside the Navy's C model on CVs, performing the same missions. Then imagine the same B model operating from smaller amphibious carriers (ie cheaper) doing the same missions. Some smart congressman (or Defense Secretary) figures that the Navy doesn't need supercarriers to do its job. That would be bad for the Navy.

Then again, if the Navy flew B models as well as the Marine Corps, those same "smart" people might try to take away the Marine Corps tactical air and give it to the Navy. That would be bad for the Marines.

However, kobyra could also be right and the Marines may conclude that B model makes too many compromises v. the C model to work effectively on CVs, and procure the C model too. In any case, we'll find out in a few years.



------------------------------------------------------------------------

Mongol General: ...Conan, what is best in life?
Conan: To crush your enemies, see them driven before you, and to hear the lamentation of the women!
Mongol General: That is good.
 
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