An issue with a/c that rely on signature management and in particular their cross section shape is it drives significant cost into there manufacture it also means changing the shape and any aperture is extremely difficult particularly increasing them in size. So any future upgrades needs to fit into a shape defined very early in the a/c’s design. A/c that do not wish to place signature management so high as a design driver has much more freedom
shark bait wrote:Correct. Build a new air frame, uprate an existing engine, and use existing sensors in an open system to be incremented over time. I posted a slide from the USAF on page 37 that repeats this message.
I would agree they are obvious learning from Saab on this as this was the core of the gripen upgrade. But the system has to be true open architecture many systems claim they are but when you scratch the surface they really aren’t. In particular US ITAR restriction are a complete pain.
On the main points of your argument shark bait I would agree and have for some time thought the same. On engines you could have an engine option of an ej200 or f414 for example should you wish but this would need to be agreed very early and a common set of interfaces for both power plants. The one thing this future jet needs to ensure is the power plants have sufficent power and thrust growth for the life of the product ej200 has this in spades.
On podded systems I think this is key they are much easier to upgrade and allow smaller companies and countries to contribute a high tech solution without the need to invest in designing there own aircraft. The best example on current aircraft is as mentioned the litening pod. How do you this going fwd well as an example in the civil world you can certify an aircraft to fly with or without its wingtip fairing for example.
So how about clearing a series of “pods” or external fuel tanks. So say removable wing tips for das or side radars, Also design an aerodynamic shape with a specified weight and c of g that can be the bases for either fuel, senors of any type, or a series of weapons and clear it early in the flight test program. There is significantly less effort required to certify the pods if shape/weight/ and C of G remain constant . Everybody who then wanted a new sensor or weapon in the aircraft knows what they need to design it around. If the pod held future weapons, like with paveway 4 if they’re clever in the design then new variants can be integrated with much less pain. (Think tornado Hindenburg tanks and raptor)
Lastly and it moves into thru life maintenance, I’ve never been on civil program that at its heart hasn’t attempted to push service intervals to there max and limit aircraft down time, as well as incorporating features that mean your maintenance people need less training, it can be as simple as not using locking wire on a nut or having self lubricating bearing so they don’t need greased, right up to replacing hydraulic systems with electrical ones, to the design of some of the structural members it doesn’t seem to placed as high up the requirement list on military programs as it should. But it all needs considered and designed in for the start.
The ultimate starting point is does your combat force need to be entirely low observable and while I don’t think it does it’s a debate that I’m sure will be at the heart of the problem team tempest will have to answer