The author added up the total contracts including for: non-recurring sustainment and logistics support, special tooling and test equipment, ALIS equipment, spares, ancillary support equipment, training equipment and on and on, then divided by the number of aircraft in the lots.

So…

(1) Is the cost of buying an aircraft in your world recurring or non-recurring?
(2) Do aircraft operate in a bubble or do they require supporting equipment?

But, the more pertinent point is not that the JPO figures are wrong, or that the defense aerospace ones are not right either. It is that the JPO has been caught lying. Again.

How can this department be trusted to even count the f__king moon never mind engender trust amongst (1)the people who are paying for the aircraft (that is the tax payers, both within the US and within customer countries in case you are wondering), (2)potential foreign defense decision makers and (3)the people who will have to depend on the thing to work in a war.

http://www.defense-aerospace.com/articles-view/feature/5/159230/the-myth-of-declining-f_35-prices.html

The average unit cost of the F-35 Joint Strike Fighter continues to rise, despite claims by the program’s Joint Program Office and the prime contractor, Lockheed Martin, that they are decreasing with each annual production lot.

The program office bases its claim of lower costs on just a few of the many contracts it awards for each lot, and disregards the others. When announcing the main LRIP Lot 6 and Lot 7 contracts on Sept 27, 2013, for example, the JPO stated that:

”This award increases the value of the aircraft and associated production efforts on the LRIP 6 contract to $4.4 billion ($3.7 billion awarded …[in]…December 2012 ….and $0.7 billion awarded today) ….for production of 36 aircraft, with average aircraft unit cost approximately 2.5 percent lower than LRIP 5 aircraft.”

In fact, the real LRIP Lot 6 unit cost ($ 230.3 million) is fully 19.6% higher than the Lot 5 unit cost ($192.6 million) according to our analysis of DoD contract data.

JPO’s claim of lower Lot 6 unit prices is based on the two contracts identified above whereas, in fact, it awarded 27 Lot 6 contracts between Feb 9, 2012 and 0ct 9, 2014. The total value of these contracts is $8,292.6 million (see Table 1), almost double the $4,400 million cited by JPO.

Dividing the $8,292.6 million value of all the Lot 6 contracts by the number of Lot 6 aircraft (36) produces an average unit cost of $230.3 million, which is almost double the unit costs announced by JPO: $103 million to $120 million, depending on the version. (These figures were corrected from “$98 million to $116 million” as mistakenly stated in the story as initially posted.)

It should be noted that these contracts do not include the cost of the aircraft’s engine ($15 to $25 million depending on the variant) which is contracted separately. Once engine costs are added, Lot 6 unit cost increases to about $250 million.

JPO has offered no explanation for having counted only two of the 28 contracts it awarded for Lot 6. Half of these contacts were awarded before JPO announced its unit cost estimate on Sept 27, 2013, and should have been counted; another 13 were awarded after that date, and so could not be counted.

Because of these two procedural quirks, JPO’s unit costs are — unsurprisingly – wide off the mark. JPO did not respond to a request for comment.

Surprise, surpise, sur-f__king-prise.

Wait till the koolaid suppers line up to defend the indefensible.

However, for the F-35 due to the crucial design of the forebody for DSI interaction, this resulted in the unusual phenomenon of the inlet lip and wing LE vortices being pulled ‘inwards’ – hence the solution wasn’t so straight forward:

Vortices parallel at the forebody then diverging at the usual 10-20 degree angle. Not being pulled in.

Not the same aircraft. Hence not the same problems. There are a load of reasons for the vortex shed from the intake lip behaving differently – forebody/nose shape, detail contouring of the lip, shape of the intake side surface, shape of the canopy and the fuselage aft of the canopy, even right back to integration of the engine nozzle into the airframe.

Notwithstanding the issues of yaw control by moving them closer to the centre of mass, the limited options for a solution makes the arbitrary changes to the shape, surface area and location of the ‘J-31’s’ vertical stabilisers (albeit on a model) seem all the more ridiculous.

Why? Because you don’t understand the reasons?

If you move them forward, you may loose some moment arm, but you also may gain aerodynamic effectivity at moderate AoA by removing them from the shadow of the wing. But lose it at v. high AoA.

If you decide to increase the sweep angle of LE and TE, you can look to align more of the tailplane to the region not masked by the wing/horizontal tailplane at high AoA. You also get the added benefit of moving the moment arm back. But the drawback of increased stresses on much of the structure.

Of course, any change to authority of the control surfaces enables a resizing of said control surfaces.

Obviously, the most efficient wing design @ supersonic speeds would be an iteration of the delta- like the F-22, T-50 and J-20.

Strictly speaking; all the above, including F-35 and J-31 are iterations of the delta. None being an actual delta at all.

The 3 versions of the F-35 have had sustained G limitations and transonic acceleration times increased as a direct result of differences in the trapezoidal wing designs. All 3 suffer from severe transonic roll-off & buffet @ different portions of the flight envelope.

But we aren’t talking about the F-35.

Little matters like tail volume ratio, wing t/c, wing a/c, wing aeroflexure and forebody separation characteristics contribute to stability margin over the AoA range as well as maneuverability.

The J-21’s marginally higher aspect ratio and thinner airfoil is not going to mitigate these inherent problems associated with the trapezoidal wing at both transonic and supersonic flight regimes.

The F-22 has a trapezoidal wing. So has the PAK-FA and the J-20.

Yes they most certainly did. But did they do so without significant structural changes to the fuselage forebody and inclusion of VGs? – They most certainly did not!

In the wind tunnel, yes they did.

But LM had the benefit of the data collated with the NASA YF-17 program.

These include a fuselage forebody that is anathema to the transonic-area rule (like the F-35),

Look again. This time include the volume effect of the cockpit.

Its not perfect, but it does follow the guideline loosely.

the higher aspect ratio will not mitigate the lower lift of the thin airfoil and the efficiency of the airfoil that is optimised for supersonic performance will be undone by wave drag.

The wing produces more than enough lift at supersonic speeds. All wings do. Lift is not an issue, Cd0 is.

The thinner aerofoil will help reduce Cd0. But will hurt transonic (and maybe even supersonic) turn performance – LE and TE devices can offset this though.

What appears to be arbitrary redesign and relocation of the vertical stabilisers in the new model @ Zhuhai, is like some afterthought.

LM investigated numerous vertical tail positions for the F-22 both fore/aft and inboard/outboard, eventually settling to where they are today. VLO, stability, control and buffeting all played a part in selection.

So anybody taking bets on how many years there would be between program start and the French leaving to go design their own fighter this time?

The Rafale is more suited to the needs of its users than Eurofighter.The French were right.

If the EF had carrier borne capability, the 2 RN carriers would have been CATOBAR from the get-go. There would have been no money wasted on flipping and flopping and there would have been no compromise of sphere of influence.

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But, getting to the core of the issue. It really is all about interface definitions.

Define (and reserve) interfaces for now and future use for each sub-system; reserve interfaces for future undefined systems. That includes the bus types, the language, the power requirements, volume, cooling etc. Designate different iterations of each sub-system which are scalable and modular.

Software modules can then be built and scaled as appropriate.

That means airframe designers have a range of “commercial” off-the-shelf units to pick from. Benefits being:

– It removes much of the development cost of an individual aircraft.
– It reduces the risks of subsystem.
– It eases the incorporation of latest technology into an existing aircraft.
– It reduces the design/development time of any new aircraft.
– It allows quicker and cheaper customisation of airframes to the tasks they will perform.

The only people that wouldn’t benefit would be the shareholders of military hardware companies. But its not the role of the defence forces or the politicians to preserve their profit margins.

SAC designed their J-31 by standing on their shoulders.

Have you ever worked on the detail design of an aircraft? For sizing or check?