6
$\begingroup$

I know that radar cross section (RCS) tests were performed on geometric models of both the YF-22 and the YF-23 prototypes submitted for the Advanced Tactical Fighter (ATF) competition, but were the same tests performed on the actual YF-22 and YF-23 prototypes when they were in flight?

Both designs had the correct shaping to their outer machine lines in order to minimize radar cross-section, but there is a noticeable difference between those prototypes and, say, the production F-22 in terms of very small details i.e. RAM inlays, putties, tapes around doors, etc. A similar phenomenon was observed with the X-35 JSF when compared with the F-35 Lightning II development aircraft. That makes me wonder if such an RCS test was part of the ATF competition.

Improve this question
$\endgroup$
5
  • $\begingroup$ I wonder how useful that would be, since the measurement would be further off from the final product than simulation and ground testing. $\endgroup$
    – user3528438
    Commented Oct 26, 2017 at 19:30
  • $\begingroup$ Probably not, I would guess. A numerical model would probably more closely predict the F-22's RCS than the pre-production, pre-EMD YF-22/23. I'm fairly certain they tested scaled models on the pole before the YF-22 even flew in 1991(?). And they did later (1999) verify the F-22's RCS with a 'full-scale replica built to production tolerances'. If YF-22 pole testing did happen, Ben Rich might've mentioned it in Skunk Works, but I don't recall. $\endgroup$
    – Hephaestus Aetnaean
    Commented Oct 26, 2017 at 22:35
  • $\begingroup$ Also, here's the YF-23 DEM/VAL presentation by Paul Metz and Jim Sandberg. It's been too long since I've watched it to recall whether they touched on pole testing. $\endgroup$
    – Hephaestus Aetnaean
    Commented Oct 26, 2017 at 22:36
  • $\begingroup$ Yes. But not in flight. There are no means of accurately plotting the RCS of an airplane in flight; only one direction can be measured, and it won't even be consistent. $\endgroup$
    – Therac
    Commented Dec 12, 2023 at 7:11
  • $\begingroup$ Some of the RCS pole models are now on display at the gates to the Pima Air Museum in Tucson AZ. The production aircraft are painted with radar absorbent coatings and have special treatments around gaps. There are many other similar subtle details that probably weren't done to 100% for the YF fly-off. The aircraft were very much prototypes and under development. Notice how much smaller the 22's vertical tails got between YF and F. You can expect that a lot of the RCS details had not been fully developed, technology was evolving very rapidly at that time. $\endgroup$
    – Rob McDonald
    Commented Dec 12, 2023 at 23:26

1 Answer 1

Reset to default
1
$\begingroup$

Low radar cross section (RCS) was a principal 1986 requirement for the Advanced Tactical Fighter (ATF) selection program that selected the YF-22 and YF-23 prototypes for a fly-off competition.

I am certain that both prototypes, or at least accurate models, were pole-tested during the evaluation period. Remember, this was in 1986, when computer modeling of RCS was in its very early stages of development. This testing was probably done at either the Area 51 RCS test range, or Lockheed's Helendale RCS test range.

For more first hand information about the YF-23, see this YouTube video.

Improve this answer
$\endgroup$

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .