Could it be those are from mission configuration data sheets rather than physics books? I’ve only seen this kind of notation as a kind of “mission-related shorthand” for stores really. Numbers you add up to get a drag value that dictates your technical and procedural requirements. Those aren’t true coefficients though. You can’t derive a force from a dimensionless coefficient without introducing the necessary dimension at some point.

Physics books in regard to general aerodynamics usually work with different properties and start a level deeper than that, the classic aerodynamic equation being Fd = 0.5*p*v²*Cd*A. Of course it actually gets a bit more complex for planes and wings with different kinds of drag acting upon the object and each other if you analyze things even closer than that and look at the single components.

The thing about the F-22 vs. F-15 debate is: Yes, the F-22 does not carry the drag penalty of the F-15’s external stores, but in turn the F-22’s weapon bay presents (or may present) a bigger face area that carries aerodynamic importance in itself. The question is whether the F-22’s better airflow offsets any possible face area penalties.

🙂

The CD includes everything and is independent of frontal area, and is at the same time it is misleading. It can only be compared for aircraft with comparable wing loading.

If you are actually interested in the force enacted upon the aircraft, then face area matters. Cd might be a nice indicator of how “sleek” a design is, but for the aerodynamic force and actually resulting drag you can’t just ignore face area.

It sounds easier than it is. And without some hard data from the wind tunnel to back it up, any CFD is just wasted effort.

It’s far from a wasted effort. There might still be an error margin of 10-15% for subsonic applications, but I think you are selling CFD short. Having a proper model, defining air throughput for intakes and turbine with a rough estimate of thermodynamic transfer of assumed materials should actually give pretty good ballpark figure. Even without thermodynamics, just a rough estimate of the forms’ airflow properties would be interesting enough.

Anyone have Cd and face area values around for both planes?

Wasn’t here someone around that used ANSYS for a living? What about plugging some HQ 3D models of both planes into it and getting at least an estimate on drag coefficient and face area for both?

All speculation is just speculation really.

They’re good enough that the F-22 can use it to que AIM-120s without ever firing up the APG-77.

How does the F-22 handle communication like mid-flight updates with the AIM-120 then?

And 1° accuracy at 50nm would work out to ~0.9nm tolerance if I’m not mistaken. What the supposed range of the -94 for a valid target solution for an AIM-120?

The additional thrust would certainly be good news for every Rafale pilot. Hope it happens.

Interesting that there is no statement on the Typhoon, which is EADS’s top-of-the-shelf product and would have been most interesting to have some data on.

It’d be also interesting how this simulation-based improvements could affect ordnance shape and the interaction between external loads and the airframe on planes without internal bay.

The whole point of it is that it homes in on the jammer – without needing to burn through the jamming!

No, the point is that after burn-through you can launch without having to support the missile with command guidance until its seeker can go active. Which means that as long as the post-burn-through target keeps the music on, the missile will home in on it while you do very comfortable notch or Split-S and are running home for tea and medals.

You still need to burn through.