Forum: F-35 Design & Construction

Well I don't know much, but this tech has me concerned. What I really need are some nice homespun homilys that only Gums ( who has great engineering sense yet is also a warrior in the classic sense ) could deliver. If I had a few mil I would give it to Gums to get his input after he looked at it.

Anyway here is what gets me concerned. ( granted there are smart people working on this, but that by itself doesn't always count, as history has shown )

The Tech:

Becareful what you ask for you might get it- Since the cute little liftfan airshow in 2001 is over. Now the brainiacs have to figure out:

Weight-A real mission jet with avionics, weapons, fuel etc all piled in, ....does not an airshow make, Where the 2004 weight concerns reared their ugly head and we were all told it was being managed by the "concerned" officials. Well, if anything with add ons jets pork out and get heavier during their career with upgrades not lighter. This means the B must have almost zero growth room. You want to add something later? Good luck. Even when it goes into the external carry mode.... weapons pylons have significant weight. With the lift fan you have to consider that the fan can only turn so fast and put out so much power or heat-wear-lube issues will change from the original design. The weapons carry on this should be very interesting as it's claim of a 450mile range will be a real magic act when it goes to hang external stores. ( Most of what the Marines will need.......... Will not require stealth :::gasp::: )
Here is some other interesting reading:
Icing of the fan gizmo:
http://ir.goodrich.com/phoenix.zhtml?c= ... highlight=

And my favorite which should warm the hearts of all Sailors/Aviators when dealing with Navy environs ---- Corrosion.... ( some good reading )
http://www.dodsbir.net/sitis/archives_d ... mark=28810

As Harrier ops have shown us- Everything has to work like a toyota during the take-off or landing phase.

Operations-
-In a dirt base setup close to hostiles. How many of these things can be taken out by a mortar/rocket attack?
-What kind of "brownout" can occur that affects visual safety when landing and taking off? And how many of these things are we going to wreak in the first 5 years in training ops alone?
-What maintenance and how reliable will this thing be in a dirty setup? With a liftfan gizmo that has unknown abilities to tolerate a bare base setup.
-What logistics will be required to support this thing out in the wild?
-Based on that, will the dirty bare base ability hype... be just that? Where it will only end up on clean airfields or semi-clean like A-10?
-In the end will an A-10 doing what it does... be more useful?
-Salty- Where a Harrier has a footprint of 0.82 area, this will have one of 1.09. Will current amphibs...really....REALLY be able to support a hand full of these things better than a Harrier?
-Will the Harrier out perform the JSF-B in some areas of practical USMC methods currently used? i.e. -I just want to drop bombs with x sorties a day for CAS and not re-invent the wheel on a mission concept that is basically: Simple.

-At 60+ each ( probably more now ) million and climbing for the B model. I am not all to happy to see this thing spawn.

How much money would it cost to make a more reliable version of the Harrier motor instead.... and produce more Harriers... if the USMC is so in love with jump jets?

Note I didn't bring up the RN as while I love that organization, for me as a taxpayer, what they do is none of my concern.

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You bring up some excelent questions. I can only respond to a little of it. the range I can do. the F-35B was never advertised as VTOL but STOVL so that allows it to get airboerne with heavier loads, just like the USMC harriers do. Also this thing carries 13,000 lbs of gas, twice the harries gas load. That aught to get it to 450 miles from base, have time to fight, and fly home. As for the dust issue, I share your concern. The only nice thing about its hover that I know of is that the temperature beneath it is much lower than harrier so it will not melt/burn the ground beneath it. How does Harrier do with dust? Verry intelligent topic you bring up and it requires intelligent answers by intelligent people. Anyone else have something to add?

Let me try answering:

"As Harrier ops have shown us- Everything has to work like a toyota during the take-off or landing phase."

Incorrect. The high accident rates that all Harriers have periodically suffered are not primarily due to mechanical failure. In particular the RN flying Harriers off their small carriers have a take-off & landing record second to none. The harrier has an excellent mechanical reliability record but is very difficult to fly.

"In a dirt base setup close to hostiles. How many of these things can be taken out by a mortar/rocket attack?"

Same as any other aircraft or helo in similar circumstances. You are making invalid assumptions about the intended use of F-35B's if you think they'll spend their life operating out of clearings in the jungle.

"What kind of "brownout" can occur that affects visual safety when landing and taking off? And how many of these things are we going to wreak in the first 5 years in training ops alone?"

Accident rates are projected to be lower than aircraft currently in service. Mainly because of the advances in aircraft control. F-35 STOVL ops can be tried in the simulator today. With a few mins instruction, you could land one safely yourself.

"What maintenance and how reliable will this thing be in a dirty setup? With a liftfan gizmo that has unknown abilities to tolerate a bare base setup."

Once again you appear to be making assumptions about operating envirnments that are not correct.

-What logistics will be required to support this thing out in the wild?

You mean in the jungle? Same logistics that would be required on a ship or at an airfield.

"Based on that, will the dirty bare base ability hype... be just that? Where it will only end up on clean airfields or semi-clean like A-10?"

There is no dirty base hype. The intended STOVL operating environment is regular airfields, ships and 2nd level airfields like your local GA field. There's no intention of operating these aircraft out of clearings in the jungle .

"In the end will an A-10 doing what it does... be more useful?"

Not for missions requiring operation in high threat areas where A-10's will be a liability. Or in areas where A-10's cannot operate at all. Like from the sea.

"Salty- Where a Harrier has a footprint of 0.82 area, this will have one of 1.09. Will current amphibs...really....REALLY be able to support a hand full of these things better than a Harrier?"

Yes because its not the aircraft's own footprint that matters but it's logistical footprint. Which for the F-35B is significantly smaller than the Harrier. USMC assets in service and being developed will be able to operate a lot more than a handfull of F-35's which is why so many are being purchased.

"Will the Harrier out perform the JSF-B in some areas of practical USMC methods currently used? i.e. -I just want to drop bombs with x sorties a day for CAS and not re-invent the wheel on a mission concept that is basically: Simple."

Yes. In some cases by an order of magnitude. The F-35B can carry more bombs, a lot further and a lot faster with a hugely greater ability to detect, target and destroy. BTW, if you are implying there's still a significant role for unguided bombs, there isn't.

"At 60+ each ( probably more now ) million and climbing for the B model. I am not all to happy to see this thing spawn. How much money would it cost to make a more reliable version of the Harrier motor instead.... and produce more Harriers... if the USMC is so in love with jump jets? "

Reliability of the Harrier motor is not the issue for the marines. the issue is that their aircraft are getting old and will soon run out of flying hours. They need a replacement. A replacement that can operate from their assets performing Marine missions against any enemy.

BTW, the F-35B full internal weapons & fuel i.e. max stealth, will have an ROA of just under 500 nm. With the addition of external payload and a couple of external combat tanks the ROA goes up to approx 600 nm. Both flying USMC mission profiles. Before you get too distainful of those numbers, go find a current Navy jet from any country that can match either.

thats why navy uses IFR to go 800 miles. Harrier has longer legs than a Hornet.

Additions to RonO's replies:

"What kind of "brownout" can occur that affects visual safety when landing and taking off? And how many of these things are we going to wreak in the first 5 years in training ops alone?"

Accident rates are projected to be lower than aircraft currently in service. Mainly because of the advances in aircraft control. F-35 STOVL ops can be tried in the simulator today. With a few mins instruction, you could land one safely yourself.

Harriers avoid brownout by maintaining a 20-30 knot forward velocity during landing. F-35B would operate in a similar manner. AM2 mat also serves to keep the dust down but must be secured properly to keep it from being blown away.

"What maintenance and how reliable will this thing be in a dirty setup? With a liftfan gizmo that has unknown abilities to tolerate a bare base setup."

Once again you appear to be making assumptions about operating envirnments that are not correct.

Only a code 1 jet would attempt to operate from a FOL. Broken jets would divert to a facility that can handle maintenance (has support equipment and spares on hand).

-What logistics will be required to support this thing out in the wild?

You mean in the jungle? Same logistics that would be required on a ship or at an airfield.

Inability to get fuel and weapons to the field is the biggest hindrance to FOL ops. You need adequate VERTREP or the ability to truck the stuff in. Fuel is brought in using bladders or bowsers. Small weapons are preferable because they can be loaded by hand (3 healthy lads on a GBU-39 or 4 with hernia bars on a MK 82-derived weapon). Anything over 500 lbs requires a jammer and seriously hinders turnaround time.

"Based on that, will the dirty bare base ability hype... be just that? Where it will only end up on clean airfields or semi-clean like A-10?"

There is no dirty base hype. The intended STOVL operating environment is regular airfields, ships and 2nd level airfields like your local GA field. There's no intention of operating these aircraft out of clearings in the jungle .

"In the end will an A-10 doing what it does... be more useful?"

Not for missions requiring operation in high threat areas where A-10's will be a liability. Or in areas where A-10's cannot operate at all. Like from the sea.

A-10 is a MANPADS magnet. If the A-10 is going slow and low enough to visually ID a target, then the enemy's MANPADS teams can track and engage the A-10. Bet your paycheck that A-10 will not provide effective CAS if they are busy dodging MANPADS.

The solution is to operate outside MANPAS range, and this requires datalinked information from the ground units in contact with the enemy. F-35B has that datalink and can put JDAMs within a couple meters of those coordinates a few seconds after the call. This, sir, is effective CAS.

That said, a CAS is not as effective as GMLRS due to potential timing and availability issues. The Marines' need for GMLRS is more critical than any CAS jet.

"Salty- Where a Harrier has a footprint of 0.82 area, this will have one of 1.09. Will current amphibs...really....REALLY be able to support a hand full of these things better than a Harrier?"

Yes because its not the aircraft's own footprint that matters but it's logistical footprint. Which for the F-35B is significantly smaller than the Harrier. USMC assets in service and being developed will be able to operate a lot more than a handfull of F-35's which is why so many are being purchased.

You can also expect a lower break rate for F-35B. If it doesn't break as often, then it isn't down for maintenance. This provides a force multiplier over the Harrier and generates more sorties.

"Will the Harrier out perform the JSF-B in some areas of practical USMC methods currently used? i.e. -I just want to drop bombs with x sorties a day for CAS and not re-invent the wheel on a mission concept that is basically: Simple."

Yes. In some cases by an order of magnitude. The F-35B can carry more bombs, a lot further and a lot faster with a hugely greater ability to detect, target and destroy. BTW, if you are implying there's still a significant role for unguided bombs, there isn't.

"At 60+ each ( probably more now ) million and climbing for the B model. I am not all to happy to see this thing spawn. How much money would it cost to make a more reliable version of the Harrier motor instead.... and produce more Harriers... if the USMC is so in love with jump jets? "

Reliability of the Harrier motor is not the issue for the marines. the issue is that their aircraft are getting old and will soon run out of flying hours. They need a replacement. A replacement that can operate from their assets performing Marine missions against any enemy.

It's not just reliability issues but added capability due to datalinks, ESM and advanced weapons that cannot be retrofitted to Harrier economically.

BTW, the F-35B full internal weapons & fuel i.e. max stealth, will have an ROA of just under 500 nm. With the addition of external payload and a couple of external combat tanks the ROA goes up to approx 600 nm. Both flying USMC mission profiles. Before you get too distainful of those numbers, go find a current Navy jet from any country that can match either.

Thanks guys. Great reading.

One of the problems I heard about thd harriers was that they would ingest their own exhaust and this would cause bad things to happen and the engine to shut down (vertical landing only). The lift fan makes this... well impossible. It's basically like you have two sources in basic fluid flow. The create something of a wall between them based on the strength. The stream tube going into the engines when at rest will look something kinda like a funnel (there's a more complex shape, but its really hard to describe). Anyway, the inlet shape should help with the ingestion problem.

Also, I believe the Harrier could only do a vertical take off with half weapons load and maybe half fuel (whatever it is, it's a reduced amount). Another thing to consider, you can launch the B models a lot faster than any carrier jet. This is because of the tiny takeoff roll it has to do. Now, I'm not exactly sure of if the Marines have formalized carriers like this, but it could be a huge help. Ok, I'm not sure why I'm writing all this its beginning to ramble so before I put my foot any farther into my mouth, I'll shut up.

LordOfBunnies wrote:

One of the problems I heard about thd harriers was that they would ingest their own exhaust and this would cause bad things to happen and the engine to shut down (vertical landing only). The lift fan makes this... well impossible. It's basically like you have two sources in basic fluid flow. The create something of a wall between them based on the strength. The stream tube going into the engines when at rest will look something kinda like a funnel (there's a more complex shape, but its really hard to describe). Anyway, the inlet shape should help with the ingestion problem.

That is why Marines are trained to keep a 20-30 kt forward speed during landing. It stops hot gas ingestion and keeps rocks out of the fan.

LordOfBunnies wrote:

Also, I believe the Harrier could only do a vertical take off with half weapons load and maybe half fuel (whatever it is, it's a reduced amount). Another thing to consider, you can launch the B models a lot faster than any carrier jet. This is because of the tiny takeoff roll it has to do. Now, I'm not exactly sure of if the Marines have formalized carriers like this, but it could be a huge help. Ok, I'm not sure why I'm writing all this its beginning to ramble so before I put my foot any farther into my mouth, I'll shut up.

LHAs and LHDs are the key assets for transporting Marines and their kit to the beach. CH-53s (and V-22s) doing troop transport and VERTREP will be the primary tasking. As such, the ability to generate CAS sorties is way down the list of things to do. CAS will come from the CVNs and USAF until the Marine beachhead and Harrier/F-35B FOLs are well established.

BTW, Purdue, School of Aero & Astro, 1978, here.

DJ, the marines published material show that they are viewing future F-35B's operations in rather a different fashion than you indicate and if you look at the new amphibs under development you can see that reflected in the much higher importance given to F-35 operation. There is clear recognition that the marines will need organic air support regardless of whether a carrier group is present or if the air force can cover from HNS. Also given some of the logistical problems you articulated earlier and the greater stand off capability of the F-35B compared with the Harrier, FOB's are much less likely and in many scenarios do not appear at all. To be blunt, F-35 can do more from further away and is a lot easier to support onboard than detached. So there's a lot less incentive for FOB's.

cheers

Elp, I wouldn't be worried about the engineering aspects of the F-35 in any way, shape, or form (except for the lack of gun on the B and C models, that worries me). What you should, and do, worry about is the cost. If the thing go through another revolution in the aerospace spiral of death, it will officially be holy **** expensive. I don't think development is done yet so I don't think a true cost per plane can yet be determined. We all understand your concern, but at this point there's certain things we can't do. One of them is just sort of drop everything in Iraq. We did some things and its a bit FUBAR right now. We can't drop it, even if we should, it will become our worst nightmare. Imagine stripping someone bare and throwing them into Siberia. Now we're helping them to find what they need to survive. Anyway, whatever. I'd love for us to be out of their, but at this point its far more dangerous to us in the state it's in than what it could be.

It seems the F-35 got hit worse by the spiral of death than the F-22. I don't really want to get into policy discussions, I'm woefully underarmed. Though, the our armed forces seem to adapt wonderfully to use what they are given. With not as great planes in Vietnam, they eventually got pretty good kill ratios (F-4 wasn't great, but through training pilots became much better using it too its fullest (that's not meant as an insult)). Eventually the F-16 Block 60's won't be able to "go downtown" as others like the F-35 will be able to farther in the future. I know about the other things the F-35 is killing, but at this point the money is invested. Low rate production may allow some of the other programs. Sorry, I'm rambling a bit... ok a lot. Anyway, don't worry about the engineering aspects of the F-35 is pretty much what I wanted to say.

Both the B and C are to carry conformal gun pods. Does that address your concern?

And JSF has not suffered the kind of program inflation we've seen on F-22. It might but right now it hasn't.

The main worry for me with JSF is the weight issue, (putting tech` transfer aside) especially on the "B" model. I know it was given a haircut but there are still concerns over it`s weight reported in the "popular" press.

Even if the weight issue becomes a non-issue on early production blocks, planes don`t get lighter, they only get fatter the more they mature, ie new weapons/uprated engines, wings, etc....

As an example, the Lightning F-2 was arguably the best mark as far as handling was concerned, compared to the F-6 which was much heavier, with greater range/fuel. Ok the Lightning NEEDED more fuel but you see what I am getting at....

You are dead right. Weight growth is the achilles heel of all STOVL to date. Helo's too.

I worry about the shedload of new software that has still to be written.

This article is about the F-135, which runs 190F hotter than desired.
http://www.aviationnow.com/avnow/news/c ... 2906p2.xml

IMO the F-35B should be cancelled, equip the F-35C with a 3D thrust vectoring nozzle and apply ESTOL technology to it.
ESTOL experiments are done in the X-31 VECTOR program, it proved that the landing speed can be decreased by 31% and the landing run decreased by approx 78%. During landing the stress in the airframe and the arresting gear is less than a conventional no flare carrier landing.
Add to this: less development costs and risks, TVC will increase manouvrability and range and the F-35C is a better performing plane.
Disadvantage: you will need to modify the 40,000 ton Wasp / Iwo Jima class LHAs with catapults and arresting gear.

Question, in a British aviation magazine it was stated that the STOVL requirements for the F-35B were influencing the performance negatively of the other versions, is this true?

RonO, what do mean with 'program inflation' on the F-22?

Designing a single aircraft for the needs of the Air Force, Marines & Navy means that to some degree all 3 services have to accept compromise. Having said that I don't know why anyone would say the STOVL requirement has impacted the overall design any more than say the Navy requirement to fly from carriers. I've not seen an article that makes that claim. Was it from Air Forces Monthly by any chance? There's a writer for that magazine that is so anti-JSF, he prints totally biassed, one sided material full of distortions and & half truths that cannot be relied upon.

I meant the huge price increases that the F-22 program has gone through. It's cost more and more for fewer and fewer aircraft. Not cool.

Forum: F-35 Design & Construction

B Model Engineering