F
@f-22
European 🇪🇺 tweeting in 🇩🇪🇬🇧🇨🇵 about aviation, politics, misc; AvGeek, Airframe Engineer; Exil-Saarländer
"Their results cannot be trusted if users have no knowledge of their internal workings..." "Computed results must in some way be judged or compared with expectations."
By the way, a third way of load introduction in the wing would be to have beam above and below each rib, which hold load pads and clamp the wing in between. Like that, you don't need two actuators (above & below), but one can push and pull from below. Usefull for shoulder mounted wings like A400M
Honest answer: I don't know. But from what I see, it is highly unlikely that these are bonded pads: 1) To avoid disbond or peel off, you typically have a much larger area to reduce the N/mm² loading. Check the grey blocks on the VTP front and rear spars in the pic below 2) If you look again at the
The challenging tasks are ultimately becoming the ones we are the most proud of. Looking forward to add another aircraft in prototype livery to my collection in the coming years.
And to add some drama: for us stress engineers, this test campaign is the "ultimate" moment of truth (pun intended). We have often worked for 4-6 years on the sizing of the aircraft, and only these tests give a final verification. And yes, such tests have failed in the past!
The load level is shown in the test room on a little clock in steps of 0.1 up to 1.5. Each time a step is reached, the test leaders check if any engineer reports a problem (e.g. strains too high, or defect strain gauge), before going to the next level. Once reaching 1.5, the load is held for a
Finally, this test was a maximum wing up-bending case that was done before the first flight. Typically, before first flight, you test only to a safety factor above 1.0, but below 1.5. The ultimate test with 1.5 and more test cases follow after the first flight.
Moments along the wing and fuselage as in the most severe conditions ever expected, times a safety factor of 1.5. To ensure that this is properly done, the load applied by each actuator is planned ahead for each test case and load level and measured in real time during the test.
Wing are represented by many small cables pulling at the wing covers, and some rods penetrate the upper fuselage to connect to so-called whiffle trees attached to the seat rails and cross-beams of the floor. With this, you try to generate the same total forces and
Mentioned the displacement transducer. They measure simply the displacement: how much does the wing deflect at its tip, how much at the pylon position, etc. For the displacement, the predictions should be in a band of +/-5%. So with each test case, you verify your models and if your models are fit
Gauge output tells us if the measured strains correspond to the predicted strains in our models and if a strain in the test is close to failure (then we might stop or pause the test to not damage anthing). This is what the people in the test room are doing. The straight lines that you see on the
well, the strain (=difference in length under load divided by original length) on the part. During the development, the structure is sized against maximum allowable strain values from a large database (generated by many many different small material coupon tests, see picture below). Thus, the strain
closes completely around the aircraft. Afterwards, you also see the installation of the load introduction elements and the immense amount of cables leading to the 12000 sensors distributed in the aircraft. These are mainly strain gauges but also displacement transducers. The strain gauges tell us -
to the actual product. These are e.g. dummy engine pylons, HTP or landing gears. In the following, you see the test rig itself, which is a huge metal construction that allows the installation of the actuators but also gives access for inspections after each test. The fully assembled test rig
located in the Jean-Luc Lagadère site of Airbus. Fun fact: the same hangar was later used to build the Beluga XL. While the MSN5000 is rolled in, you see already some interesting features: there are parts painted in bright red. The red colour indicates that these are test means which do not belong
Youtube schlägt mir - warum auch immer - einen Live Ausschnitt von Massive Attack vor. Und mein Hirn bildet bei dem Thumbnail sofort eine Assoziation... ihr seht das doch auch oder?
What’s the cultural reference you must frequently have to stop yourself from making at work, because no-one else would get it? Mine is “I wouldn't do that. It's a load bearing poster”.
It depends. The russian Su-57 does this, which is also somewhat of a heritage from legacy designs like Su-27. They have basically a wing plane and engines underneath. So the Su-57 weapons bay is in between. Others move it more in front of the main wing attachments. YF-23 seems to do both...
I think it is more about the duct running through it. Combine this with the (s-)shape required for stealth, and you have another large object running through the CG area which you can barely move around. Below, I added a picture of a F-35 frame. The inlet dominates, weapon bay left and right.
Another important point from my perspective - which I also have mentioned during FCAS discussions, in german, below - is that the weapon bay is key and if you have to store larger weapons in it, it becomes more and more complicated. bsky.app/profile/f-22...
Great article about the F-47 and new sightings. The interviewed Darold Cummings also gives a great insight into the dynamics during aircraft development. As a structures guy, I can relate 🤭