The F-35 - Inventing the JSF with Dr. Paul Bevilaqua

[basher54321]

The F-35 - Inventing the Joint Strike Fighter with Dr. Paul Bevilaqua


https://www.youtube.com/watch?v=McwqjUoNhAE

[ricnunes]

Thanks for sharing the video

[mor10]

Thanks for sharing. Enjoyed that a lot!

[spad_s.xiii]

I saw that on Twitter and a lot of people commented on the preferred canard configuration and why they abandoned that. Also why the F-22 got its tail configuration. But I thought that was common "knowledge"(true or not) and not a big revelation. Anyway, interesting to hear it from him also.

He doesn't seem to be a big fan of all the functionalities in the HMD. I guess it costed the project a lot of money and time. But it's cool and you must also make the marketing people happy.

Besides many interesting details I think it is a very informative talk about general aircraft design process for non-professionals and not just for F-35, even if all aircraft designs have their specific problems and solutions. Making complicated technology and science interesting for people outside your field and at the same time not too basic is difficult.

[disconnectedradical]

What's interesting, is that Paul Bevilaqua stated that the reason for the JAST/JSF design moving from canard-delta to the current wing-tail, is because of maneuvering requirements, particularly post-stall similar to the F-22. This lines up with the Lockheed Martin publication for AIAA in 2018 about the F-35 air vehicle design, which stated that the design changed from canard-delta to wing-tail because of maneuver requirements particularly for the USN CATOBAR variant, which needs additional lift and control authority at slow speeds.

I always heard from various people that if the JSF had just been USMC/USAF with only an F-35A and F-35B, then perhaps the design would likely have been a canard delta. Although, that's maybe up in the air because General Dynamics, which took over a big part of the JSF design when they got acquired by Lockheed in 1993, was prejudiced against canards.

[quicksilver]

A good article on the already much-examined X-35 vs X-32 subject —

https://www.msn.com/en-us/news/technolo ... r-AA1Pqp9d

Although not stated in this article, in addition to shortcomings in meeting the precise handling requirements for CV launch and recovery, the delta planforms would also have been the most problematic for the generation of ‘jet-induced lift loss’ (ie ‘suck down’) for the STOVL designs.

[disconnectedradical]

A good article on the already much-examined X-35 vs X-32 subject —

https://www.msn.com/en-us/news/technolo ... r-AA1Pqp9d

Although not stated in this article, in addition to shortcomings in meeting the precise handling requirements for CV launch and recovery, the delta planforms would also have been the most problematic for the generation of ‘jet-induced lift loss’ (ie ‘suck down’) for the STOVL designs.

Interesting, what is the reason for that? I thought lift loss is mainly due to hot gas ingestion, which is more result of the STOVL propulsion system, i.e. lift fan vs lift engine vs direct lift, rather than the wing arrangement.

The article mentions the X-32 having problems with lift loss, but that seems to be result of the propulsion system rather than it having a delta wing.

[quicksilver]

Here’s a very technical discussion of jet-induced lift loss (also from Bevilaqua).

http://aero-comlab.stanford.edu/jameson ... qua_v2.pdf

In short, as the jet gets closer to the landing surface, the jet fountains under the the aircraft create a pressure differential that results in a loss of lift. It actually takes more thrust to land than to hover due to this loss of lift nearing the landing surface. In the Harrier, you’d start to notice the effect below 10-12’. The strakes and LIDS fence, mitigated the effect until the WOD was more than ~15kt. You should notice that F-35B uses the partial opening of the weapons bay doors for the same intent.

[hornetfinn]

I
He doesn't seem to be a big fan of all the functionalities in the HMD. I guess it costed the project a lot of money and time. But it's cool and you must also make the marketing people happy.

From what I've seen and heard, it seems that some pilots love the HMD and others could easily settle for HUD. For sure they did this bit early and technology wasn't quite there yet at the beginning but now it seems very robust and mature system. I do think HMD does give a lot of advantages especially with Block 4 capabilities (sensors and software). For example being able to see target boxes and missile warning boxes well outside the HUD FoV must improve SA a lot. I would also bet that night landing on a carrier or road base must be much easier to do with HMD providing full wide FoV night vision all around.