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• #2602
USAF use F 18 non?
Non. F/A-18 is a US Navy aircraft.
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• #2603
People call them canards, but they're apparently* foreplanes.
*I couldn't give a toss either way, but some argue that canard refers to a configuration where the forward surfaces provide lift rather than just control.
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• #2604
F/A-18 is a US Navy aircraft.
(and USMC)
The F-15 isn’t going anywhere soon. They’re still extremely capable (the F-15E in particular), and the USAF wasn’t allowed to buy enough F-22s to replace their F-15Cs.
Still being produced, and there’s been a semi-stealthy variant proposed with RAM and internal weapons carriage.
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• #2605
Yes curio.
I mean the F 18 is a newer airframe.
Carrier based or not seems odd to limit to just the Navy.
It actually looks as tho the F 15 will outlast the F 18 wtf.
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• #2606
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• #2607
but that's a canard
[smoulders in Robert Mitchum]
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• #2608
canard refers to a configuration where the forward surfaces provide lift rather than just control.
Hard to see how they could control without producing lift.
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• #2609
The F-15 still outperforms even the Super Hornet. All that extra weight for the sake of being carrier-capable compromises it in pretty much every other way.
That's the reason the French fell out with the Eurofighter consortium and did their own thing with the Rafale.
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• #2610
I could have a guess at the distinction...
A wing is designed to produce lift by virtue of the difference in pressure on each side.
A control surface simply takes advantage of the reaction to the air hitting it at an angle.
Presumably the Eurofighter's foreplanes fall into the latter. The Piaggio Avanti seems to be a common example of a true canard aircraft, the difference is pretty obvious...
Edit: I guess another difference is that in level flight, the Eurofighter's foreplanes aren't doing anything significant. Looking at the Avanti, without those things at the front it would immediately fall out of the sky.
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• #2611
A wing is designed to produce lifting force by virtue of the difference in pressure on each side.
A control surface is designed to produce manoeuvring force by virtue of the difference in pressure on each side
FTFY
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• #2612
Indeed. The point of a control surface is that they generally increase or decrease the overall amount of lift of the aerofoil they are attached to (or comprise, in the case of the Typhoon’s foreplane, or a stabilator etc.) by modifying the aerofoil profile/angle of attack.
I’m not aware of any control surfaces that aren’t an aerofoil shape, but even if it was just about reaction due to a surface hitting the air at an angle, that would still be about creating a pressure differential between the lower and upper surfaces.
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• #2613
I'll give you the benefit of the doubt and assume you're being pedantic, but here's a picture anyway...
Top one will produce a force if it's rotated relative to the oncoming air. Presumably at the expense of significant drag. Any difference in pressure is a consequence.
Bottom one will generate lift at a neutral angle to the airflow, with minimal drag. Difference in pressure is deliberate.
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• #2614
I’m not aware of any control surfaces that aren’t an aerofoil shape
There are spoilers with no curvature, and the effect on the aerofoil to which they are attached is not one of changing camber or AoA
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• #2615
Top one will produce a difference in pressure if it's rotated relative to the oncoming air. Any force is a consequence
Again, FTFY
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• #2616
The symmetrical aerofoil produces no lift at neutral AoA, but it produces lift in the same way as the cambered one does at a positive AoA. It’s not about air molecules smashing into the lower surface (just use a flat plate in that case), it’s lift due to pressure differential.
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• #2617
Quite correct, I should have said ‘control surfaces that don’t modify the shape of an aerofoil’.
You could probably argue that a spoiler does modify the camber/AoA of an aerofoil, analogous to the way a split flap does. At least, I say you could, but it’s 24 years since I last studied aeronautics and I’ve forgotten most of it, so my degree of confidence about what does and doesn’t modify an aerofoil’s camber/AoA is not high.
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• #2618
ARTHUR: Oh, yes. About that. Um, I wanted to ask you something, Skipper. Mum was telling me this morning that planes fly because they’ve got wings.
DOUGLAS: Is there anything that woman doesn’t know?
ARTHUR: But she didn’t really explain – why do wings lift us up?
DOUGLAS: Ah, well. Essentially …
MARTIN: Uh, Douglas, he asked me. Listen carefully, Arthur. The wing is curved on top but flat on the bottom. When it meets the air, it splits it in two. The air that goes over the top has further to go, so it has to go faster to keep up with the air underneath. That reduces the pressure above the wing, giving us lift.
ARTHUR: Ah, fantastic! Thanks, Skipper! I totally get it now.
MARTIN: You’re welcome.
ARTHUR: Except … why does it have to?
MARTIN: Why does what what?
ARTHUR: Why does the air on the top have to keep up with the air on the bottom? Why don’t they just split up?
(Everyone stops walking. There’s a long pause.)
DOUGLAS: … For the sake of the kids?...
DOUGLAS (talking over him): Arthur, you were asking why the air over the wing has to keep up with the air underneath.
ARTHUR: Ooh, yes. Do you know?
DOUGLAS: Indeed I do. Attend: the air is not passing over the wing; the wing is passing through the air, so the curved upper side stretches the air forced over it apart, reducing pressure, producing lift. The lift pushes up; the weight pushes down – so as long as the lift is more than the weight, up we go. And that, my friend, is how an aeroplane flies.
ARTHUR: Got it! Right, yes! Cracking! I completely get it now.
DOUGLAS: Good. You see, it’s actually quite easy to grasp when it’s explained properly by someone who understands …
ARTHUR: So that’s why planes can’t fly upside down.
DOUGLAS: Er, yes they can.
ARTHUR: Can they?
DOUGLAS: Well, of course they can. Haven’t you seen the Red Arrows?
ARTHUR: But … doesn’t that mean the curved side of the wing is on the bottom, so the lift is pushing down as well as the weight? How does that work? -
• #2619
You could probably argue that a spoiler does modify the camber/AoA of an aerofoil
Some types do, I was thinking about the vertical spoilers found on, for example, sailplanes.
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• #2620
just use a flat plate
Even tilting a barn door creates lift by raising pressure on one side and lowering it on the other 🙂
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• #2621
Well, yes. But the Typhoon’s foreplane isn’t a flat plate because it wouldn’t be terribly efficient, and it also doesn’t produce lift due to a ‘reaction to the air hitting it at an angle’ as stated above. Nor do control surfaces generally.
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• #2622
My understanding of why they are known as forplanes on Typhoon is they both rotate in the same direction during operation, whereas the canards on a Rafale rotate indepenantly.
Happy to be corrected as was only a verbal description I was given, albeit by numerous different people during my apprenticeship.
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• #2623
Ooof. Could it actually be the French want to use a French word? 😊
Quack!!
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• #2624
Coin!!
FTFY!
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• #2625
Bon Appetite !?
The latest variant is in the process of being delivered, they say it will stay until 2040 but the way these things go I'd expect Eagles to be in service in 2050