Forum: General F-35 Forum

At another forum that isn't mostly about airplanes at all, F-35 (among other things) came up as part of a conversation about politics and military expenses. One particular person made a series false claims that I was already familiar with about F-35, but also threw in a few I couldn't be completely sure what to say about.

One was "Several countries backing out of their JSF commitments are buying {F-18E}s". I've seen this claim that other countries were cancelling a few times before and know it was a lie then, but it's been a while and something could have changed since then, which I somehow missed despite reading here. Did I miss this?

"JSF will haul 18,000 pounds, even if its hardpoints individually are rated higher. Certain weapons systems require a higher point load than the average." I know that this is in fact the standard number given, but I've never understood why, and this situation just reminded me of it. The individual capacities of the hardpoints (on A and C) add up to 21300: 1300 on the four dedicated air-to-air stations and 20000 on the six heavy-duty ones. Why is the total less than the sum of its parts, and does this oddity happen to other fighters' reported payload numebrs as well?

When someone else asked about a fight between F-22 and F-35, he gave this list of F-22's advantages over F-35: "Supercruise, higher service ceiling, much more endurance, far more stealthy, far more maneuverable, and most importantly far better RADAR and EO systems." I presume EO means electro-optical, but I haven't seen anything on F-22's sensors other than active and passive radar, so what's going on there? And why would the plane with the shorter (as listed) combat radius have higher "endurance"?

Also, about prices: I know there are a bunch of different things that could be called a plane's price/cost (flyaway, weapons system, procurement, acquisition), and there's also the issue of including or excluding R&D along with production models, but when you see a number quoted, how do you know exactly which one it is, and how do you find a different one when you need it for apples-to-apples comparison (to avoid comparing one's flyaway cost to another's procurement cost or such)?

F-16.net Sponsor

I know he is wrong on the EO systems as I don't think the F-22 has any EO systems really. I also think the "far more endurance" comment is wrong. The endurance comment is wrong (though things like that are variable really depending on how you draw up the mission profile) but the F-35 carries more internal gas and should consume less with just one engine.

delvo wrote:

One was "Several countries backing out of their JSF commitments are buying {F-18E}s". I've seen this claim that other countries were cancelling a few times before and know it was a lie then, but it's been a while and something could have changed since then, which I somehow missed despite reading here. Did I miss this?

Rubbish! Easiest way to counter this BS is to ask them to list which countries they are referring to. Given the only Super Hornet operators are the USN and RAAF, both of which are still behind the F-35, they don't have far to go.

delvo wrote:

When someone else asked about a fight between F-22 and F-35, he gave this list of F-22's advantages over F-35: "Supercruise, higher service ceiling, much more endurance, far more stealthy, far more maneuverable, and most importantly far better RADAR and EO systems." I presume EO means electro-optical, but I haven't seen anything on F-22's sensors other than active and passive radar, so what's going on there? And why would the plane with the shorter (as listed) combat radius have higher "endurance"?

More crap. Again, I would simply ask him for proof of this and then smack down his so called facts.

delvo wrote:

Also, about prices: I know there are a bunch of different things that could be called a plane's price/cost (flyaway, weapons system, procurement, acquisition), and there's also the issue of including or excluding R&D along with production models, but when you see a number quoted, how do you know exactly which one it is, and how do you find a different one when you need it for apples-to-apples comparison (to avoid comparing one's flyaway cost to another's procurement cost or such)?

Best way to deal with price is once again to ask them to clarify exactly what price they are referring to (typically they won't even know there is a difference.) and then counter with what do they think the equivalent is for any other platform.

I have a very detailed piece explaining the various prices in detail if ever you want it.

delvo wrote:

"JSF will haul 18,000 pounds, even if its hardpoints individually are rated higher. Certain weapons systems require a higher point load than the average." I know that this is in fact the standard number given, but I've never understood why, and this situation just reminded me of it. The individual capacities of the hardpoints (on A and C) add up to 21300: 1300 on the four dedicated air-to-air stations and 20000 on the six heavy-duty ones. Why is the total less than the sum of its parts, and does this oddity happen to other fighters' reported payload numebrs as well?

Capacity of individual hardpoints is based on the heaviest loading (including weapons, pylons, and launchers) ever to be mounted there. The maximum total load capability is based on maximum gross takeoff weight. MGTOW is always less than the empty airplane plus crew, plus full fuel, plus maximum weapon load. So the maximum flyable weapon load is always less than the sum of the individual hardpoint capacities.

This condition allows individual hardpoints to be loaded to their capacity, but not all hardpoints to be so loaded simultaneously.

Evidently, the F-35 MGTOW limits the total hardpoint load to 18,000 lb. I don't know about all other fighters, but the F-111 and F-16 are similarly restricted.

An example of flying maximum total hardpoint load occurred back around 1970, during F-111 flight test. The mental giants running that program decided it would look cool to have photos of the -111 flying around with 50 750lb bombs. So they loaded up all hardpoints (6 bombs on MER on 8 wing pylons, plus 2 in the weapon bay), put in a little fuel to reach MGTOW, and took off. Once around the pattern was all it could manage, landing in zone three afterburner.

bigjku wrote:

I know he is wrong on the EO systems as I don't think the F-22 has any EO systems really.

Could EO mean something unrelated to electro-optical sensors, though?

gtx wrote:

Easiest way to counter this BS... I would simply ask him for proof of this and then smack down his so called facts... counter with what do they think the equivalent is for any other platform...

I don't intend to go back to that thread and argue F-35's qualities there any further than I already have. I hit a few of the biggest slowest softballs he lobbed just to make the point that his sources weren't honest, and got him to back off from his rabid hyperbole about the plane to merely that it had to make some sacrifices in one area in order to meet goals in other areas, as all planes do. That's good enough in a thread that's actually about whether one of the major American political parties could benefit from changing its conventional position on military spending, and has other people in it who want to talk about that more than they want to see the thread get overwhelmed by our posts just going back and forth at each other on a tangent. Very Happy

I'm just asking about some stuff that came up there for my own enlightenment. (And some of it, like the total payload being less than the sum of the individual hardpoint payloads, has made me wonder for quite a while; this just reminded me of it and made a good place to lump it in with the rest.)

gtx wrote:

I have a very detailed piece explaining the various prices in detail if ever you want it.

I do. I know I've seen a couple of threads where plane pricing was discussed before, but didn't really look into them at the time, and now my curiosity's been poked.

johnwill wrote:

Capacity of individual hardpoints is based on the heaviest loading (including weapons, pylons, and launchers) ever to be mounted there. The maximum total load capability is based on maximum gross takeoff weight. MGTOW is always less than the empty airplane plus crew, plus full fuel, plus maximum weapon load. So the maximum flyable weapon load is always less than the sum of the individual hardpoint capacities.

The "always" part is what I don't get. If the limit is the total takeoff weight, that seems like you could keep it down to that by holding back on EITHER fuel OR weapons, but reporting a maximum payload with this reduction built in means declaring that it always has to be the weapons that get the reduction, never the fuel, as if the latter is impossible.

(I understand that this is academic because the weapons for the 1500/2500 hardpoints weigh around 1000 or 2000 anyway, but I'm trying to get the theory down.)

I just don't know how well an F-35 would do against an F-22 is even really pertinent save for an ally turning against us (in which case we embargo his a$$ and the debate becomes about how many F-35s can you store in a single hanger) or if there is another US Civil War. So its just an odd one to me. even if the F-22 completely destroys an F-35 the F-22 isn't coming back and its not being exported so i guess it would just be a fun aviation fact.

I too had someone tell me that countries were walking away from the F-35 and I asked "really? who?" (actually curious, hadn't heard that) and I got the response "oh actually no one has yet oops"

delvo wrote:

johnwill wrote:

Capacity of individual hardpoints is based on the heaviest loading (including weapons, pylons, and launchers) ever to be mounted there. The maximum total load capability is based on maximum gross takeoff weight. MGTOW is always less than the empty airplane plus crew, plus full fuel, plus maximum weapon load. So the maximum flyable weapon load is always less than the sum of the individual hardpoint capacities.

The "always" part is what I don't get. If the limit is the total takeoff weight, that seems like you could keep it down to that by holding back on EITHER fuel OR weapons, but reporting a maximum payload with this reduction built in means declaring that it always has to be the weapons that get the reduction, never the fuel, as if the latter is impossible.

(I understand that this is academic because the weapons for the 1500/2500 hardpoints weigh around 1000 or 2000 anyway, but I'm trying to get the theory down.)

Of course, you are right about off-loading fuel to increase weapon load and stay within MGTOW. It's possible, but usually not practical, as in the F-111 war story. Such heavy loads cause excess drag and weight, reducing range beyond that caused by reduced fuel. I have no operational experience, but just observation tells me normal weapon loads are somewhere around half the maximum capacity.

So, what gets reported as a plane's "payload" is actually its "payload at 100% fuel" instead of what it really could carry? That's a very strange way to report numbers, especially when outsiders (people who don't know about that oddity) can be expected to repeat the numbers as if they meant what they sound like they mean. For example, Wikipedia says F-35A has six "external pylons on wings with a capacity of 15,000 lb" but then adds the internal bays "for a total weapons payload of 18,000 lb", which would leave the internal bays only 1500 apiece. Aside from making the math not really work, that makes carrying anything over 18000 pounds sound impossible, rather than merely not usually what they'll do in real life.

And even Lock-Mart's own page on the thing just says "weapons payload: 18,000 pounds", which has the same effect: making it sound like going over that amount is impossible. They're the thing's designers, makers, and sellers, which doesn't give them much reason to say its limit is something less than what it actually can carry. This makes me suspect there's a technical reason I'm missing why it really is impossible. (And if it isn't, then are other fighters' payloads also underreported like this? Is this an industry standard? I can't tell without seeing those convenient "hardpoint maps" for the others.)

It's probably also important to note that, for legacy aircraft, a portion of their "maximum payload" has to be devoted to carrying external fuel tanks for the fuel that is already included in the F-35's internal load.
And, while the F-35 is not meant to be superior to the F-22 in a dogfight, it does have a number of tricks for that environment that the F-22 doesn't. I don't think the F-22 has a superior radar, either.

PS: Considering fuel and MTOW doesn't even solve the problem, it just makes it even odder. Searching for "F-35 fuel capacity", I get several sources saying it's 15000 pounds. But the difference between MTOW and empty weight, which should be the amount of stuff the plane can carry, is 40700, and that fuel capacity plus a "total payload" of 18000 pounds only adds up to 33000, leaving a 7700-pound gap (a difference of over half of the reported fuel capacity or a third of the payload). Even putting back in the "lost payload", bringing that total up to 21300, still only has the plane carrying 36300, which still leaves a gap of 4400 pounds. (That's a difference of almost a third of the reported fuel capacity or a fourth of the payload.)

Is MTOW being overreported by 6.7%-12.6%?

This also happens with other planes. For example, F-18F:
Empty weight: 32081
Fuel capacity: 13550
Payload: 17750
Total: 63381
MTOW: 66000
MTOW-total: 2619

Not only is there a gap again, but it's nowhere near the size of the F-35's gap, so now there's also a gap between the gaps.

I know we haven't accounted for the pilot and suit yet, but they can't weigh this much, or be this variable in weight.

Does "empty weight" include oil, hydraulic fluid, and consumables?

count_to_10 wrote:

It's probably also important to note that, for legacy aircraft, a portion of their "maximum payload" has to be devoted to carrying external fuel tanks for the fuel that is already included in the F-35's internal load.

On payload and range, this guy also said some stuff about Lightning's combat radius having been based on a lighter load so the numbers aren't really comparable.

count_to_10 wrote:

And, while the F-35 is not meant to be superior to the F-22 in a dogfight, it does have a number of tricks for that environment that the F-22 doesn't. I don't think the F-22 has a superior radar, either.

The radar is older but it's also bigger and more powerful, so I don't mind giving him that. My main objection to what he said there would be all the uses of the word "far". But my only real question here was about what "EO" could be, since I already knew about Raptors' speed, ceiling, stealth, and "supermaneuverability".

On the 'costs' comparison issue, that's definitely a beast and very difficult one at that with respect to comparing the F-35 with apples-to-apples (vs other platforms such as the affordable, mature F-18EF, eg). Note there will be retro-work required for today's LRIP F-35s, on top of the unexpectedly massive unit WSC costs. But in short, if the F-35 Program were killed at around 185 jets, the APUC cost for the F-35A variant alone would likely be more costly per jet than the F-22's after all the necessary incremental upgrades to eventual follow on block 4/5 were completed!

count_to_10 wrote:

Does "empty weight" include oil, hydraulic fluid, and consumables?

There are several "empty weight" specs, but those you mention could be considered included in "basic empty weight" - if your "consumables" describes something required by the aircraft to fly.

Forum: General F-35 Forum

A few questions from a debate at another site