How Effective is the F-35's VTOL?

I was looking through pictures of the F-35 and comparing it to the early visions of the prototype and stumbled upon an image of a JSF using VTOL. I then compared this to the earlier VTOL capabilities of the AV-8 Harrier. Some further reading revealed 3 variants, F-35s A, B, and C. The VSTOL-capable one is the F-35B. I was really wondering if anyone else had some facts and comparisons between the F-35B and current VTOL and STOL capablle aircraft. Opinions are cool too.



F-35 VTOL


Harrier VTOL

The F-35 is not VTOL capable in any variant, it is too heavy. It is instead a STOVL aircraft which is more easily achievable. Also the nozzle can only rotate while transitioning to and from the hover, it is not a manouvre control like on the Harrier so there is no TVC either, although the CTOL F-35A and C could be fitted with such a device.

[edit on 25-5-2006 by waynos]

I don't think the F-35 can do viffing (vectoring in forward flight) to the extent a harrier can, which is a shame.

Originally posted by Darkpr0
I was looking through pictures of the F-35 and comparing it to the early visions of the prototype and stumbled upon an image of a JSF using VTOL. I then compared this to the earlier VTOL capabilities of the AV-8 Harrier. Some further reading revealed 3 variants, F-35s A, B, and C. The VSTOL-capable one is the F-35B. I was really wondering if anyone else had some facts and comparisons between the F-35B and current VTOL and STOL capablle aircraft. Opinions are cool too.

Depends on what context you mean by 'effective'. The USN has a long history of accepting aircraft which were /drastically/ under spec so long as they carried a 'navair spoken here' label. That said, IMO, the type is neither operationally suitable nor operationally effective.

Suitable.
Because if the Marines get their way, they will lose their entire CVTOL force of Hornets AND Harriers to pay for a _much_ smaller (appr. 200-250) STOVL JSF. This will effectively mean that they are no longer the USN's RAG or Reserve Air Group as STOVL airframes cannot be integrated with big deck carriers on either the shooting or catching end without royally farking up the rest of the airwing cycle.

Effective.
Here too, the question is less 'how well?' than 'was it ever intended?' because, on a comparitive basis, the STOVL aircraft has always been a 450nm radius airframe while From The Sea, Forward takes the litoral bounds as /beginning/ some 400nm inland. And indeed both the F-35A and certainly the F-35C are 650-700nm airframes. Ignoring the farce of 'jeep carrier' airpower as a standalone asset (with all of 8-10 aircraft onboard and definite limits to how fast you cycle them with assault helos on-spot), if you cannot contribute to the new paradigm of Day 1, Raid 1, airpower, you are worthless.

That said, Aviation Week published a list of the weight savings which were being done to make the STOVL viable after the admission of it's being some 3,400-3,750lbs overweight. Among these was the removal of 'commonality' inherent to weapons bay sized for 2,000lbX12ft munitions. Which basically means all your standoff (JSOW) and building killer (GBU-31) munitions sets. Replacing them with 'lightweight CAS munitions'. Unfortunately, this is deceptive. Because an ITER-9 is around around 100lbs and a BRU-57 and 61 are about 200-250. While a typical weapons pylon is probably along the lines of another 200lbs. So, /before/ the paired GBU-38 or quaded GBU-39, you are looking at a good 500-750lbs. Add in the munitions, and you are back to 2,000+, easy. FOUR such pylon sets of external (faster to combat turn) munitions then comes up to about 8,000lb warload. And this won't fly or at least land, with any kind of margin.

Of course there are other indicators. Such as redesigning the wing lap-joints THREE TIMES. And then 'thinning the skins'. Before shifting more gas inboard to the spine. While deferring external loads qualification beyond basic fuel and AAM loads. Which sounds like they are trying to avoid loading the wings at all, something those nations which are going to use the jet as a conventional fighter will not be happy about and which in particular caused no end of problems with the early F-16 and 18 as structurally contributive wing stringers cracked along fastener lines and either had to be coldworked or replaced.

Add to this a 12-15 percent reduction in 'carrier margins around the boat' and you start to see a trend towards using the machine in the 'same ol' way' as the Harrier itself was. With nominally 70-80% internal fuel and a large number of ROCKETS (which can be parent stationed and which multiple the number of passes by salvo count) as a baseline beachead softener. Of course this is INSANE because the value of the platform (113 million and climbing) as well as the reality that STOM or Ship To Objective Maneuver operations should be taking the LHA/LHD _well_ over the horizon, even before troops 'ignore the surfzone!' to go deep inland. i.e. Speed of transit, depth of radius and safety while in a sophisticated IADS environment factors all must be increased exponentially in order for an F-35B as a _stealth_ followon to the Harrier to have any real meaning.

Mechanically, the powered lift system has a lot going for it. Because, unlike the F404 on the the Harrier, you are not stuck with a limited number of compressor stages and a tiny gerbil-core set of turbines turning a MONSTER fan. Whose coldflow thrust is lost during STOVL (requiring a large quantity of cooling water) and whose inefficiency during cruise eats up radius. By literally 'decoupling' the vertical lift component from the up and away segment of flight, all that weighted inertia on the front end (compression) is lost. While, assuming the softclutch and spinup system continues to be reliable, the SDLF itself is larger and thus more powerful (with less hot velocity) than say the lift-only engine pairing on the Yak-38.
My principle questions then being:

1. Can one man do it all?
Ans: It depends. Rowing the boat is now more or less an autopilot procedure. Shooting the ducks is simple ONCE ACQUIRED. But unless you have a raft of UAVs to do the volume sanitization with a lot more loiter than the JSF can bring to the pointy end of the radius, you cannot ignore the effects of searching and sorting on the single-crew as a defacto self-FAC'ing asset. The Marines have limited UAV access and none with the operational depth and station time of even an MQ-1. So the Row+Shoot+_Spot_ factor is being ignored 'for the convenience of the Corps flying club'. The JSF is not likely to gain a second seat, due to the way the airframe structural box is already so badly compromised with cutouts for bay doors and the like and the STOVL version is even less so because of the weight issue.

Mod Edit: BB Code.

[edit on 6/6/2006 by Mirthful Me]

2. Why Pay For Supersonics?
The majority of even BVR air combat is now done below the Mach. As netcentric AAW and in particular LRAAM from LO assets (who cares who illuminates because you STILL never see it coming) further modify this, the need for a speed edge, forcing a merge will decrease even further. Add to this the reality of only-2 AMRAAM and a micro-airwing deckload and supersonics are not worth the effort. Which is where the F135's legacy inheritance from the F-119 begins to bite you because even cruise SFC is NOT that great. And particularly for a >250nm 'CAS' jet, there is also limited justification for 14,000lb fuel load in a 30,000lb empty weight airframe. If you are generating 18,000lbs forward and (up to) 26,000lbs aft, but paying a MONSTROUS TSFC increase over even the F100/110 series to get there, you are making a mistake for a payload of

ch1466,
your posts regarding real world elements of deployability, capability and cost of airframes that have been feilded and ones that are in development are very well thought out. they are grounded in reality rather than a loose and subjective critera of what makes a great plane, such as, "the F-22 is the best plane in the world because it's the prettiest."
in your opnion what has been the most successful aircraft to have entered service since WWII?
as for the F-35, i whole heartedly agree that the program is way to costly and does little to signifigantly advance the capability of the U.S. warmachine.

Originally posted by 140th CES
in your opnion what has been the most successful aircraft to have entered service since WWII?

This may not be directed at me, but opinion-the F-15. Many sorties and not a single loss. Well, at least not to the US anyway.

Originally posted by 140th CES
Such as, "the F-22 is the best plane in the world because it's the prettiest"

F-22 isn't the best because the prettiest is the Su-37

Couldn't resist bashing the Raptor.

don't want to change the spirit of the original topic, but F-15, good choice.
how many kills was that saudi F-15 driver credited for during the early air campaign during gulf war I?
back on topic, F-35. already too heavy and the transmission gearing for the "VTOL" feature, to delicate for the high tempo operations of actual combat.

Yes. Practical, NO! Harrier made be getting old, but it's a better machine than the F-35. Harrier was design by Sir Sydney Camm to be dead simple, and it longevity and combat record proves it worked. Boeing followed that trend and developed the only real combat capable JSF competitor. The Lockheed F-35, however, uses a system that, many years ago, was shown would work, but was not practical. Why?
1. Increased complexity of adding the shaft, fan and clutch will make it a maintainence nightmare and more battle damage prone.
2. Instead of concentrating the system into one area, it is more spread out, making it more likely it will be hit during combat.
3. With the fan off, it's dead weight and eats up a lot of space. Again, not what you want in a combat aircraft.
The Ryan XV-5 is an excellent example of a similar design being tried before and canned because it would be no good on the battlefield.
The STOVL F-35 ranks as one of the worst aircraft built by the Skunk Works.
And you can quote me on that.

[edit on 2-6-2006 by TSR2005]

[edit on 2-6-2006 by TSR2005]

The STOVL F-35 ranks as one of the worst aircraft built by the Skunk Works.

I think the MAIN problem was that the F-35 is a...(shudder)...multirole. The big thing that makes the AV-8 better is the fact that it was MADE to have VTOL/STOVL capabilities, that was what it was meant to demonstrate. And it does it well, no doubt about it. The F-35 was intended to be an affordable aircraft with the capability to handle any need fairly well. But it isn't the best at anything. At least the F-15 was a dad-blasted spectacular multirole. The F-35 has become too ambitious to be affordable, and doesn't do anything that makes people go "wow!".

So you can see it's not a bad aircraft, it's just trying to be good at too much. At least it's not as ugly as earlier visions of the JSF. Nasty...

TSR2005,

>>
Yes. Practical, NO! Harrier made be getting old, but it's a better machine than the F-35.
>>

The Harrier is a pilot killer, in all versions. Without fail. It has the highest crash rate per 100,000hrs of any jet now in inventory.

>>
Harrier was design by Sir Sydney Camm to be dead simple, and it longevity and combat record proves it worked.
>>

The Harrier never faced a true threat which could challenge it in a way that forced combat to a conclusion. It cannot suppress because it doesn't have HARM capability. It cannot maintain BVR dominance because it doesn't have the speed or the wingloading or (for the majority of it's career) the MRM to play the high fight.

>>
Boeing followed that trend and developed the only real combat capable JSF competitor.
>>

To an extent, I agree with this. But not because of the direct-lift STOVL. That feature bloated up the design to the point where aesthetics (yes, Fighter Pilots /are/ that crass and stuck up about 'what they drive') guaranteed it would lose, if it didn't trounce the F-35 in all areas. Well, the fact of the matter is that it WAS better than the Lunchmeat design in up and away flight. However; the compromise on fan-size for STOVL made it a bit of a fuel pig and it simply didn't have the lift margin to beat a _zero mission systems equipped_ mini-Raptor.

If the X-35'A' had crashed and they had been forced to use the X-35C (with the bigger wing and tails at least /partly/ representing the absent production weight), the X-32 would have won, hands down.

As is, the Marines and the USN, both the nominal reason why we 'had to have' a LO-goes-to-sea capability, have now both halved their buys, leaving the USAF stuck with the majority purchase of a platform LEAST suited it's needs.

>>
The Lockheed F-35, however, uses a system that, many years ago, was shown would work, but was not practical. Why?
1. Increased complexity of adding the shaft, fan and clutch will make it a maintainence nightmare and more battle damage prone.
2. Instead of concentrating the system into one area, it is more spread out, making it more likely it will be hit during combat.
3. With the fan off, it's dead weight and eats up a lot of space. Again, not what you want in a combat aircraft.
>>

I myself prefer lift + lift-cruise. Because I believe in the reliability of simple turbines and know for a fact that a lot of the 'dead weight' argument is pure bollocks. Of course the big problem here is that the Russians already did it and we all know 'we can't have that'.

That said, there is absolutely NO excuse for bringing ANY fighter much more than 20nm out from an (active IADS) D1/R1 interdiction target. Or 10nm from a 'CAS' followon/OOTW type threat. You don't want to choke the airspace over the target area. You don't want a blackhawk down scenario with stealth technology wreckage buried in potentially urban collaterals. You don't NEED to obey a bomb-blast delay separator on munitions TOFs for SALH. And in the case of the JSF specifically, you don't want to put the jet's rear quarter over any more look-back or lateralized threat aperture chains than you can. Even the best stealth is not perfect and the F-35 is far from being the best stealth out there.

Once you obey the basics of COE (defined by the 'better bullet theory' of MUNITIONS standoff), the number of threats which can hit you goes way down. And so too does the importance of airframe hardening and survivability factoring on lethal area.

Even so, there is no arguing that the ability to put two cold posts worth of 18-22Klbst on each end of the teeter-totter is a 'nice thing' for STOVL because it lets you put the engine at the back where it should be and fuel+weapons on a believable wing area where /they/ should be.

If they had kept to the premise of ASTOVL and CALF which was namely: SIMPLE and LIGHTWEIGHT (a 20,000lb airframe with four internal missiles or six small bombs), the JSF + SDLF proposal would be a superb system. It just wouldn't be able to fly out 650-700nm, perform 3 max-G turns and come home. Because that is not what manned CAS is about.

>>
The Ryan XV-5 is an excellent example of a similar design being tried before and canned because it would be no good on the battlefield.
The STOVL F-35 ranks as one of the worst aircraft built by the Skunk Works.
>>

The JSF is three planes sharing one name. Beyond that, it is a dinosaur in a ten years (tops) before the KT boundary of laser and maser type weapons. Most importantly, with the kinds of technologies involved, it represents an attempt to achieve everything every service wants by combining the resources of all three. Despite this, the JSF program will never break even without a huge number of allied purchases and they will only buy if we guarantee their costs by overinflating our own inventory purchases while giving away the store in terms of technology base leveraging.

At a time when the oil currency fiat is ending and the economic lead is about to change forever to slave labour states the U.S. cannot afford such huge numbers of fighters 'just to give pilots a job'.

PARTICULARLY when small IAMs and glide kits have basically allowed ONE fighter the ability to stand in for FOUR others.

What matters more is the ability to in fact CONDENSE our fighter inventory to a single service exponent which doles out squadrons to individual theater commanders base on the basing modes they have available too them.

Something which is _utterly impossible_ for the F-35 because, despite being nominally a 'joint' system, it does not have a COMMON ability to land 'wherever'.

Nor can the numbers of jets we are building for particularly the Navy (170) and Marines (240) win a war without USAF support. Small bombs or no, 10-20 aircraft in a theater on two decks is just shy of spit-in-wind worthless for the kinds of 'deep attack' targets that stealth supposedly justifies attacking.

So to make sure I get the gist of this-STOVL F-35 sucks because it doesn't fulfill what the need is in the US?

I'll buy that.

'Pure Bollocks'? Refresh my memory, did McDonnell Dougals win the JSF contract? Is the 'Forger' still in service? Did VAK 191 get put into production? Or the 'Balzac', for that matter? What was the failing of these machines? Oh, yes, that's right...they had dead weight and wasted space. True, the F-35 has a fan and not a jet, but it's still the same principal and when it's not in use,...well, that just means less fuel, or electronics, or whatever useful things could go there. It's useless and just sits there, and the rest of the plane has to drag it around. And in case no one noticed, that fan is not small, nor is it featherweight. In fact, it's worse than having a pure jet since the damaging the shaft and/or fan could damage the engine, making the whole aircraft more vulnerable to battle damage.

As far as crash rates go, your talking about training, NOT the design of the aircraft. No airforce has ever gotten away with having a poorly designed aircraft for over 30 years. From the beginning, Harrier was well designed, but more challenging to fly. I said dead simple and I meant it. Camm wanted little to no automation with the system. For what started as a new and manual method of control, it worked quite well. And since there has yet to be another VTOL fighter in service for that long, who's to say that the figure you quoted isn't a LOW figure? There's nothing really to compare it to. From the start, it was not the normal combat aircraft. That's a point too many people keep missing.

As far as combat capabilities go, Harrier has a proven record of effectiveness for it's age. It wasn't supposed to last this long, but it did. Of course it can't use HARM. That's not what it was designed for. Not all aircraft are meant to fulfill the surpession role, and the last time I check, it's not the primary role for the JSF either, so that point is not relevent. I not talking about roles, I pointing out the flaws of the STOVL version. I have no problem with the conventional versions. They will make excellent replacements for the Airforce, Navy, RAF and others who purchase it. That part Lockheed got right. But the STOVL should have been more practically design. More like what Boeing designed.

Boeing was never meant to win the JSF contract in the first place despite the fact they had a better design, and I'll tell you why. Boeing has a second income: commercial aircraft. Lockheed does not. If Boeing won the JSF contract, Lockheed would have to try and survive on only the F-22, which was scaled back over the years. Except what ever Black Projects they have, they really wouldn't have any business and would likely be out of work. As a major defence company, though, it would seem better to have them win and keep them in business. That way, Boeing doen't own everything. I concluded that when they announce the two finalist would be Boeing and Lockheed. It wasn't too hard to figure out and I really hoped Lockheed would've change the design.

From a conventional aircraft standpoint, the F-35 will be a welcome addition to air forces around the world, providing a great leap in capability, even in the US. It is well designed and has the potential to serve for many years to come in a variety of roles.
The STOVL version is primarily based on methods that, in the past, have been proven workable, but not effective, for either military or commercial use. Though one of the first to use a seperate fan for extra lift, the layout is the same as having a lift jet in the same location, and is a seperate system from the main powerplant. As has been proven, the most effective and reliable method of creating a usable STOVL is to keep the system a single unit, removing subsystems that could fail and render the other systems useless. Though a seperate jet adds addition thrust, it becomes useless in normal flight and adds more maintainence complications, especially making sure ALL systems work, rather than being able to consolidate efforts on one system. With the fan, additional problems that will arise will be transmission and clutch work, fan maintainence, and checking the transmission shaft. The added complications of the layout are not worth the risk, especially in combat.

When the Harrier came to the US, the Marines put their best, most experienced pilots in it, and had a 0 accident rate. After some time passed, they tried putting helicopter pilots in it, thinking that since it hovered and flew like a helicopter they would have an easy time with it, and could learn to fly it like a plane with no problems. Guess what happened. Accident rate skyrocketed. As your first flight in the Harrier is your solo, you don't have anyone to get you out of trouble.

[edit on 6/5/2006 by Zaphod58]

Seeing that the F-35's VTOL version can hover for more then 90 seconds which is the limit for the Harrier its already better in my book. The Harrier pushes its engines way too hard when in hover and when its water coolant tanks run dry in 90 seconds you will fry the engines out.

I konw that Harrier can hover without semidiameter, who can prove F-35 can do same?

Originally posted by ShadowXIX
Seeing that the F-35's VTOL version can hover for more then 90 seconds which is the limit for the Harrier its already better in my book. The Harrier pushes its engines way too hard when in hover and when its water coolant tanks run dry in 90 seconds you will fry the engines out.

Frankly, so what? Under what circumstances would you want to hover for a minute and a half? Would it be while you wait for your 'shoot me' banner to unfurl beneath you?

The Harrier (and the F-35B) are not intended to just sit there in the sky, the vertical lift element is solely a function of getting on and off the ground (well, back onto it anyway in the case of the JSF) which is easily attainable well within 90 seconds. So why is a 90 second limit a defect?

So i'm sittin here and wonderin with all this talk about only one of the 3 versions and the fact that my countries military wont even buy the b version but probably the a or c. So my question then comes to does anyone have any problems that they can see in this platform ie. is it way overpriced(which anyone answer it will be pure speculation) Or what use do they use the extra or gained space in these versions ie fuel armament electronics etc.

This thing is way overpriced IMHO. STOVL capability does not make up for the space you would be giving up for such a capability which has little or no usefulness in combat.